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Principles and Practice of 
 Crowning Teeth 
 
 A practical, systematic and modern treatise upon the requirements and technique of artificial 
 crown work, including some incidental reference to bridgework. 
 
 WITH 459 ILLUSTRATIONS. 
 
 By 
 
 HART J. GOSLEE, D.D.S. 
 
 Chicago. III. 
 
 JProfessor Prosthetic Dentistry and Crown and Bridgework, Chicago College of Dental Surgery ; 
 Dental Surgeon to the Attending Staff, Cook County Hospital; Foreign Associate Member 
 Society of Dentists of Norway; Member International Dental Federation; National Den- 
 tal Association; Institute of Dental Pedagogics; Illinois State Dental Society; Chicago 
 Dental Society; Odontographic Society of Chicago: Honorary Member South Dakota 
 Dental Society; Corresponding Member St. Louis Dental Society, etc., etc. 
 
 New York : 
 
 THE CONSOLIDATED DENTAL MFG. CO. 
 
 London : 
 
 CLAUDIUS ASH & SONS (LIMITED). 
 
 1903. 
 

 Copyright, 1903, by Hart J. Goslee. 
 Entered at Stationers' Hall, London. 
 
TO MY FRIEXDS 
 
 TRU.MAX W. BROPHY, LL.D., -M.D., D.D.S. 
 
 AND 
 
 RODRIGUES OTTOLEXGUI, M.D.S.. 
 
 In recugnition of their personal and professional attainments, and as a small 
 
 evidence of appreciation of their friendship, and of gratitude 
 
 for their counsel and assistance 
 
 THIS BOOK IS RESPECTFULLY INSCRIBED 
 BY THE AUTHOR. 
 
Preface. 
 
 The development of the specialty of crown and bridgework, and par- 
 ticularly of the methods of crowning teeth, has been so rapid that it has 
 probably been difficult, if not indeed quite impossible, for the average prac- 
 titioner to keep apace with the numerous modifications of, and improve- 
 ments in, the various methods of procedure which have been constantly 
 presented and advocated in the evolution of this specialty from a some- 
 what chaotic, and at best unsystematic beginning, to its present acknow- 
 ledged position as a distinct and highly artistic and practical department 
 of dental prosthesis. 
 
 It is therefore believed that there is a need at the present time for 
 a strictly modern text and reference book, embracing a tangible, syste- 
 matic and practical classification of the subject, supplemented with ade- 
 quate illustrations. 
 
 In assuming to supply such a possible need an effort has been made 
 to present the subject matter in a practical and concise form, and in a 
 more or less systematic and sequential order ; as well as to avoid, in so 
 far as possible, any consideration of methods which may have proven, or 
 which are deemed, to be impracticable ; or those which may have been 
 abandoned, or have become obsolete. 
 
 Special care has been given to the presentation of the various methods 
 which are practiced, and which are recognized as possessing merit and 
 practicability. This is deemed warrantable, and indeed essential, for the 
 reason that in the successful practice of a specialty in which a very high 
 order of art and mechanics is demanded, and which involves more or less 
 permanent application as a part of the human economy, where the con- 
 ditions presenting are so greatly diversified, there is no one best method. 
 Some procedures will be found more applicable to one case than to 
 another, and to be more practical and successful in some hands than in 
 others. 
 
 Personal equation and good judgment will dictate and enter largely 
 into, the application of the most practical method to be pursued in each 
 case, and this will usually have as much bearing upon the success and 
 serviceability of the operation contemplated, as will the degree of skill 
 which may be exhibited in the execution of the details of construction. 
 
The various methods and techni(|ue of modern procedures are pre- 
 sented and commented upon fr.jm an original and unl^ased viewpoint. 
 This is done with the belief that their respective application and practic- 
 ability will thus probably be more logically elucidated; and that their 
 merits will be less likely to be overestimated, than if they were presented 
 in the language of the original advocate, because of the enthusiasm which 
 would thus naturally tincture the claims made for them. 
 
 In so far as possible every effort has also been made to acknowledge 
 and give due credit as to the origin of the many valuable and ingenious 
 ideas and suggestions which have aided so much in the development of 
 this class of work, and in placing this specialty upon a somewhat sound, 
 systematic and practical basis ; as well as to those which have served to 
 facilitate and expedite the procedure and to relieve the patient of any 
 unwarranted or unnecessary discomfiture incident to the operation. 
 
 Where several similar methods of detail are mentioned in connection 
 with a single mode of procedure, they are invariably placed in the order 
 of their preference, unless otherwise emphasized in the text. 
 
 All reference to the therapeutic, or surgical technique possibly indi- 
 cated in the treatment of pathological conditions involving the roots of 
 teeth, or surrounding tissues, has been purposely avoided, in the belief 
 that such matter more properly belongs to works on therapeutics per se, 
 rather than to a book which is designed only as a practical, and compre- 
 hensive elucidation of the principles, practice and technique of modern 
 methods of crowning teeth. 
 
 Hart J. Goslee. 
 Chicago, 111., April 30th. 1903. 
 
Principles and Practice of Crowning Ceetb. 
 
 fiistory and Development of grown morK. 
 
 CHAPTER I. 
 
 Primitive Application of Crowns. First Application of Porcelain Crowns. The 
 
 Use of English Tube-Teeth for Crowns. The Foster Crown. The Mack 
 
 Crown. The Shell or Telescope Crown. The Gates-Bonwill Crown. The 
 
 Howland-Perry Crown. The Richmond Crown. The Biittner Crown. 
 
 The How Crown. The Weston Crown. The Logan Crown. The 
 
 Brown Crown. The Webb Crown. Application of Porcelain to 
 
 Crown Work. Various Modifications of These Principles. 
 
 While dental literature as early as the beginning of the eighteenth 
 centtiry records instances of the application of pivot teeth to roots, the 
 practical introduction of artificial substitutes for the natural crowns of 
 teeth lost through accident, or by the process of caries, and the ultimate 
 development of crown and bridgework is purely the product of the last 
 half of the nineteenth century, and must be placed to the credit of Ameri- 
 can dentistry. 
 
 As the profession itself has from humble environments grown and 
 broadened into a scientific calling with marvelous rapidity, so also has 
 the specialty of crown and bridgework, the evolution of the application 
 and construction of which forms an interesting chapter in any history of 
 the conception, progress and advancement of all that pertains to dental 
 art and prosthesis. 
 
 Besides opening new fields for higher artistic conceptions, it has 
 also materially aflected the general advancement of the profession, for 
 at one time it seemed propitious and apparently inevitable that the lattef 
 
should become divided into the separate branches of operative and me- 
 chanical dentistry, and that it would be the exception rather than the rule 
 for the average person to attain a degree of proficiency in both branches so 
 dissimilar to one another. 
 
 This specialty, however, then just budding into general favor by the 
 recognition of its possibilities, and so equally dividing the labor involved 
 between the mind and the hand, the chair and the laboratory, soon 
 proved the fallacy of such thoughts, and resulted in reuniting these 
 branches, thus greatly encouraging the unprecedented advance which 
 the profession has since made. 
 
 To crown and bridgework also can be attributed much of this 
 progress, for no field in art or mechanics offers greater opportunity for the 
 display of individual skill and artistic attainments. 
 
 The employment of these talents in any line cultivates the finer in- 
 stincts, promotes a higher sense of appreciation of nature, and draws a 
 
 Ficj.l. Fiq.2. 
 
 fine line of distinction between the tradesman or artisan and the true 
 artist; and, in the province of dentistry, enables one to more nearly imi- 
 tate, and often improve upon, the normal or abnormal conditions which 
 lend so much to the appearance and comfort of those who might other- 
 wise be prematurely disfigured or permanently subjected to discomfiture. 
 
 From available records the first application of 
 Primitive Jlpplicatlon "pivot teeth" is described in Fauchard's work, pub- 
 Of 0rowits, lished in 1728, in which mention is made of a crown 
 
 fastened to the root with a pivot, and which con- 
 sisted of a crown carved out of bone or ivory, or one of a natural tooth, 
 mounted upon the root with a roughened pivot of silver or gold. The 
 interior of the root was first filled with lead, into the center of which a 
 hole was aftervvard drilled for the reception of the pivot, the other end of 
 which had been previously cemented in a hole in the crown. Fig. i. 
 
 In the work of de Chemant, published in 1816, 
 nearly one hundred years later, much reference is 
 made to the use of "mineral paste," and a brief de- 
 scription is given of "a single tooth with pivot," ac- 
 companied with a crude illustration, which indicates 
 that it was intended as a crown to be attached to a root. Fisr. 2. 
 
 first Application 
 
 of 
 Porcelain Crowns, 
 
While other designs of "mineral" teeth were subsequently recordec 
 in French literature, in which country porcelain was first apphed, it was 
 not until about 1S40 that much effort was made toward the preservation 
 of broken-down roots, or much thought given to the problem of restor- 
 ing lost crowns of teeth, the prevailing and common practice having 
 been to extract them and insert plates ; or, in some instances, to grind 
 them down even with the tissues and retain them for the purpose of 
 preventing alveolar absorption. 
 
 About this time more progressive and esthetic 
 €ndli$b ideas were conceived which resulted in the intro- 
 
 tUbC C««tl). duction and first practical application in this country 
 
 of artificial crowns, in the form of the English tube- 
 teeth, designed and previously used for plate work ; they were ground to 
 fit the root and mounted with pivots of hickory wood. This was con- 
 ceded to be a marked step in advance — a revelation indeed — and proved 
 
 r/7.4. 
 
 the formative period of that class of work which was destined to develop 
 into such an important specialty. But the theory of the wooden pivot 
 serving as a means of anchorage by virtue of the expansion incident to 
 the absorption of moisture soon proved impracticable, because of the in- 
 adequate stability, and not infrequent occurrence of fractured roots as a 
 result of the swelling of the wood, as well as the necessary presence of 
 moisture which induced decay. Fig. 3. 
 
 Some modifications of this method are recorded whereby effort was 
 made to overcome the objectionable features and permit of the removal 
 of the crown in order to facilitate the treatment of the roots, which devel- 
 oped into a necessity as the result of sealing them up without proper 
 aseptic considerations. 
 
 The most prominent of these were the crown attachment patented in 
 1844 by Dr. J. S. Dodge, which consisted of mounting a wooden tube 
 into the root and attaching a metal dowel to the crown with plastics, which 
 fitted closely into the cylinder of wood, yet rendered its removal easy; 
 and the design of Dr. F. H. Clark, patented in 1849 and comprising the 
 insertion of a metal tube in the root which was anchored securely with a 
 
4 
 
 large-headed screw-pivot, perforated through the center to allow accu- 
 mulated gases to escape. To the projecting or free end the crown was 
 attached. 
 
 Because of the tendency of these crowns to 
 Cl)c loosen in their attachment to the pivot, and the ob- 
 
 fOStcr €rown. jections to wooden pivots, the Foster crown was pat- 
 tented in 1855, and while constructed upon almost 
 the same lines as one designed some five years preceding it, by Dr. 
 Henry Lawrence, it enjoyed quite an extensive use for a number of years 
 under the former name. It possessed almost a flat base, with a perfora- 
 tion in the body of the porcelain so shaped as to form a seat for the ac- 
 commodation of the enlarged head of a screw-pivot, by which means it 
 was anchored securely to the root. Fig. 4. 
 
 Fic^ 
 
 5, 
 
 F!j. 6. 
 
 While in the former styles the dowel was first 
 Cl)i JIlacR Crown. attached to the crown and then subsequently to the 
 root, the design of Dr. C. H. Mack, patented in 
 1872, is recorded as the first instance where the dowel was attached firmly 
 in the root before the crown was fixed in place upon it. The crown was 
 constructed with a countersunk cavity in the body of the porcelain which, 
 being filled with plastics, anchored it securely when mounted. Fig. 5. 
 
 The difficulty experienced in adapting any of 
 CbC Shell the former styles to the posterior teeth in a practical 
 
 or or permanent manner, and the desirability of restor- 
 
 Celescopt Crown. ing and preserving their normal functions, ulti- 
 mately led to the invention of the gold shell or tele- 
 scope crown, patented by Dr. J. B. Beers in 1873. though probably first 
 suggested by Dr. W. N. Morrison some few years previously. 
 
 This crown proved a great step in the line of progress and develop- 
 ment, because the construction did not require the sacrificing of tooth 
 
structure to the extent necessary for porcelain crowns, and made pos- 
 silile the better and more serviceable reproduction of natural tooth forms. 
 The seam of union between crown and root was for the first time carried 
 under or within the free margin of the gum and apparently made the 
 operation a more permanent success than had theretofore seemed pos- 
 sible. Fig. 6. 
 
 The success and practicability of this style of crown has resulted in 
 the subsequent invention from time to time of innumerable systems and 
 methods of construction, all of which while varying in detail accomplish 
 practically the same end; and, while it has done much to prove the ad- 
 visability of encompassing the end of the root with a band, and to a great 
 extent made possible the ultimate success of permanent stationary 
 bridgework, its virtues have been most grossly abused in their applica- 
 tion to anterior teeth, and through their production in ready-made form-, 
 the use of which, in justice to the artistic possibilities within the reach of 
 the modern dentist, cannot be too vigorously condemned. 
 
 Ficj . 7. 
 
 Ficj. 8. 
 
 As the result of the more or less successful ex- 
 
 Cbc periment with the Foster and Mack crowns, an im- 
 
 GatCS-Bonwill CroU'll. provement subsequently appeared in a tooth that 
 
 became known as the Gates-Bonwill crown, a patent 
 
 having been issued to Dr. W. H. Gates in 1875, and to Dr. W. G. A. 
 
 Bonwill in 1881, covering practically the same ideas. 
 
 This crown was of porcelain, constructed with a concave instead of 
 a flat base, and having a triangular perforation through the body of the 
 porcelain, afiforded a better and more secure means of attachment to the 
 root, to which it was secured by means of a metal dowel which was 
 threaded and screwed into the canal, after which the crown was anchored 
 with amalgam. Fig. 7. 
 
 Shortly after this the Rowland crown, subse- 
 
 CbC 1)0Wland- quently modified by Dr. S. G. Perry, and styled the 
 
 PCffy 0rOWIt. Howland-Perry crown, was suggested. This was 
 
 very similar to the preceding ones, but differed, like 
 
 the Mack crown, in that the accommodation for the dowel was confined 
 
 to a cavity in the body of the porcelain, instead of passing entirely 
 
 through it. This followed the then developing tendency toward the 
 
esthetic, by the preservation of the continuity of the exposed surfaces of 
 porcelain, not disclosing the end of the metal dowel or the mounting 
 material. Fig. 8, 
 
 This design was patented by Dr. C. M. Rich- 
 
 tftC mond in 1880, and consisted of a cap encompassing 
 
 KiCbltlOnd €rOWn. the end of the root, to which a facing similar to the 
 
 ordinary plate tooth was attached by soldering. This 
 
 was the first practical application of a band to a root for anterior crowns 
 
 with porcelain facings. 
 
 As originally designed, it consisted of a band, to which was soldered 
 a floor, forming a cap. To this was then attached a facing hollowed out 
 between the pins so as to accommodate a threaded dowel which, passing 
 
 Fiq .10. 
 
 •through the cap, was then screwed into a tube previously mounted in the 
 ■canal, thus attaching the crown to the root. Fig. 9. 
 
 While it was then for some time a matter of doubt and conjecture 
 as to the advisability of banding the anterior teeth, and as to whether it 
 was an objectionable or an advantageous procedure, the original prin- 
 ciple was soon abandoned because of the intricate and unstable manner 
 of attachment, and the apparent uselessness of a separate dowel, but the 
 modifications and improvements resulting from this suggestion are now 
 conceded to be the best means of securing permanence in the operation, 
 .and are the accepted practice of today. 
 
 During the early agitation of the feasibility of 
 the banding. Dr. H. W. Biittner invented a metal and 
 
 Biittnef 0rown. porcelain crown with a band wherein the method 
 employed in attaching it to the root would possess 
 the advantages of a band, and at the same time preclude its possible irri- 
 tating influences. 
 
This was accomplished by trephining the periphery of the end of 
 the root to form suitable accommodation for the band, with instruments 
 specially devised for the purpose, but the idea never met with universal 
 favor, and it was soon abandoned. Fig. lo. 
 
 A crown devised by Dr. W. S. How in 1883 
 thi Bow Crown. consisted of a thin facing with four pins and a slotted 
 back for the reception of the "screw-post," whicli 
 was anchored to the facing by bending the pins over it after it was backed 
 up, and the desired contour was then built up with solder. The extreme 
 thinness and consequent weakness of the porcelain rendered its usefulness 
 limited. Fig. 11. 
 
 F'(f .11. 
 
 Fiq.lS. 
 
 Fiq.13. 
 
 Another similar form was invented by Dr. 
 
 tbC Henry Weston in 1883 and subsequently modified. 
 
 Uleston Crown. The first design comprised a means of attaching the 
 
 dowel to the facing, which is best described by the 
 
 illustration, after which it was attached to the root. Fig. 12. 
 
 In the modification the dowel was first securely fixed in the root and 
 then the crown which was constructed with a view of being much 
 stronger, was held in contact with the root, and anchored by packing 
 through an opening for the purpose, on the lingual surface. Fig. 13. 
 
 It will be observed that up to this time the various steps in the de- 
 velopment of the work consisted of a crown and dowel as two separate 
 parts, but here a deviation in the principle was made for the purpose of 
 securing additional strength, in which the dowel became an integral part 
 of the crown by being baked in the body of the porcelain. 
 
 This crown, the first to be so constructed, was 
 
 Z\it Cogan Crown, the invention of Dr. M. L. Logan, patented in 1885, 
 
 and made with a large body of porcelain having a 
 
 concave countersunk base to facilitate adaptation to root, and a dowel 
 
 shaped more in line with scientific principles. More nearly approaching 
 
the requirements in conformation than any of its predecessors, it soon 
 became very popular, eventually supplanting all other designs of similar 
 nature, and for years has had an extensive use and appHcation. Fig. 14. 
 
 Another design was shortly afterward evolved 
 
 tbe Brown (Krown. and introduced by Dr. E. Parmley Brown, and while 
 
 of the same type, it possessed a base convex, instead 
 
 of concave, with a view of affording by means of its construction, the 
 
 greatest possible strength at the seam of union between crown and 
 
 dowel, and crown and root. 
 
 Its adaptation to the root after cutting it down properly was made 
 by using a bur which produced a concavity, to accommodate the con- 
 vexity of the base of the crown ; but the increased strength of the crown 
 being secured at the expense of the root, soon resulted in its abandon- 
 ment. Fig. 15. 
 
 Fiq.14.. 
 
 ^iQ . 15. 
 
 f^'cj . 16. 
 
 The difficulty of grinding one surface to closely 
 Cbe mcbb €fOWn. approximate another, and the conceded advantages 
 of a close union between crown and root, soon stim- 
 ulated a desire to secure better adaptation, and resulted in the sugges- 
 tion of a plate and dowel crown probably first used by Dr. M. H. Webb. 
 
 This was constructed by swaging or burnishing a metal plate to 
 the end of the root, then perforating it to admit of inserting into the 
 canal a dowel, which was soldered to the plate, to which the facing was 
 then attached. The possibilities of adaptation and its advantages have 
 become so recognized that many still so construct their crowns, and 
 they are frequently indicated. Fig. 16. 
 
 Soon, however, the advancement of the profession along those lines 
 leading to the achievement of the very highest conceptions of art, indi- 
 cated a tendency to observe the maxim "true art is to conceal art," and 
 created a desire for something that might supersede the use and display 
 of gold, something more nearly resembling and harmonizing with nature, 
 yet, still serving the same purposes. Even in this the inventive genius 
 of the profession was not long in again asserting itself, and soon after- 
 ward came the application of vitrified porcelain. 
 
The first suggestions were perhaps made Ijy Ur. C. H. Land, and were 
 eagerly studied and enthusiastically applied with varying degrees of success 
 and failure. Dentures of platinum and porcelain had been constructed and 
 worn successfully for years, hence it was readily believed that crowns 
 and bridges of the same must also of necessity be equally successful. 
 In this, however, many were doomed to disappointment, and because 
 of inadequate knowledge of the requirements, too much confidence, and 
 the over-zealous enthusiasm of early advocates, its use and practicability 
 soon became questionable, and was eventually discontinued by the great 
 majority. 
 
 There were those, however, who, still admiring its esthetic beauties, 
 and having faith in its possibilities, sought to ascertain the causes 
 of failures, and the reasons for success, with the result that its more 
 recent and modern application has approached and made possible the 
 very highest degree of perfection in dental art and prosthesis. Yet it is 
 not universally applicable, and will never supersede the use of gold. 
 The success of each must always depend in a great measure upon the 
 sound reasoning, good judgment and skilful execution and discrim- 
 ination with which they are respectively applied. 
 
 It will be observed that, from the very beginning, the innate and 
 intuitive desire for the practical and esthetic development of this work 
 to more perfectly meet the demands and requirements of the times, has 
 resulted in the presentation of many varied principles and methods, among 
 which may be also included the jacket crowns; the application of por- 
 celain facings to shell or telescope crowns; the Logan crown with the 
 addition of a band; the various modifications of the porcelain crown 
 with separate dowel, such as the Davis crown, the intradental band 
 and similar designs, and a galaxy of other varying and ingenious 
 ideas. Yet they are in the main but modifications of the original prin- 
 ciples enumerated, and, while aiding materially in the evolution, and 
 showing the trend of the development and progress of crown work from 
 its inception, their individual description would be redundant and 
 unnecessary. v 
 
 Those of practical value, use and application at the present time can 
 be treated to better advantage elsewhere than in a breif resume of the 
 development and history of this work, which is intended only to show 
 the perseverance and ingenuity of our predecessors, and the various 
 steps in making possible the success of modern crown work, for which 
 their efforts were primarily responsible. 
 
metals, jFfiioys and Solders. 
 
 CHAPTER II. 
 
 Symbol and Fusing Point of Metals Used. Noble and Base Metals. Chemical and 
 
 Physical Properties : Chemical Action, Color, Odor and Taste, Fusibility, 
 
 Malleability, Ductility, Tenacity. Physical Processes : Soldering, 
 
 Welding, Annealing, Tempering, Alloying, Troy Weight. 
 
 Consideration of the Metals : Gold, Karat, Platinum, Iridium. Alloys : Alloys of 
 
 Gold, Coin Gold, Gold and Platinum, Platinized Gold. Solders : Platinum 
 
 Solder, Gold Solders, Compounding Solders, Brass, Dorrance's Alloy, 
 
 Silver Solder, German Silver, Fusible Alloys, Soft Solder, 
 
 Refining Gold, Etc. 
 
 One of the first essential duties incident to the successful execu- 
 tion of any Hne of work in art or mechanics is a thorough practical 
 knowledge of the materials used; hence, in the construction and appli- 
 cation of crown and bridge work, wherein the use and manipulation 
 of the metals and their combinations forms such an important feature, 
 it is materially necessary that the dentist should be acquainted with 
 their characteristics, physical properties and methods of manipulation. 
 
 This is imperative only that he may the better understand their 
 appHcation, for it no longer becomes necessary for him to be an expert 
 metallurgist, to refine or alloy, prepare or roll his plate material, or to 
 combine and make his solders, alloys, etc., since the manufacturers and 
 supply houses now furnish them in all grades desired; yet a practical 
 knowledge of the methods and detail of manipulating them serves to 
 cultivate and make possible their more skilful application. 
 
 Of the fifty-two metallic elements known to, and so classified in 
 chemistry, but a few of them in their metallic form are used in the me- 
 
II 
 
 chanics and arts pertaining to dentistry; hence, in this connection it is 
 only necessary to refer to or consider those the physical properties 
 and characteristics of which are of common use and application for 
 practical purposes, and which are contained in the following table: 
 
 Name. 
 
 1. Gold. 
 
 2. Platinum. 
 
 3. Iridium. 
 
 4. Copper. 
 
 5. Silver. 
 
 6. Zinc. 
 
 7. Lead. 
 
 8. Tin. 
 
 9. Bismuth. 
 
 10. Cadmium. 
 
 11. Antimony. 
 
 12. Aluminum. 
 
 13. Iron. 
 
 14. Nickel. 
 
 Metallurgy divides the metals into two groups 
 noble and Base known as the noble and the base, so classified 
 metals. because of their affinity for and property of com- 
 
 bining with oxygen. 
 The former, having less affinity, do not so readily combine with it 
 by absorption from the atmosphere, and are more easily separated from 
 its combination when subjected to heat; while the latter, having a greater 
 affinity, and absorbing it more readily, are separated with much more 
 difficulty because their compounds are not decomposed by heat alone. 
 
 Noble Metals. Base Metals. 
 
 Gold. Copper. Cadmium. 
 
 Silver. Tin. Antimony. 
 
 Platinum. Zinc. Aluminum. 
 
 Iridium. Lead. Iron. 
 
 Bismuth. Nickel. 
 
 •mbol. 
 
 Fusing 
 
 Poin^ 
 
 
 Fah. 
 
 Cent. 
 
 Au. 
 
 2016 
 
 1 102 
 
 Pt. 
 
 3632 
 
 2000 
 
 L. 
 
 More refract 
 
 ory than Pt 
 
 Cu. 
 
 1996 
 
 1091 
 
 Ag. 
 
 1873 
 
 1023 
 
 Zn. 
 
 773 
 
 412 
 
 Pb. 
 
 617 
 
 326 
 
 Sn. 
 
 442 
 
 228 
 
 Bi. 
 
 507 
 
 264 
 
 Cd. 
 
 442 
 
 228 
 
 Sb. 
 
 842 
 
 450 
 
 Al. 
 
 1292 
 
 700 
 
 Fe. 
 
 3000 
 
 1600 
 
 Ni. 
 
 3000 
 
 1600 
 
 €U$$ific<itioii. 
 
 
 
12 
 
 CDcmicdl ana PDvsical Properties. 
 
 While all metals possess distinct individual properties characteristic 
 ' of themselves, it becomes necessary for us to consider only those of such 
 practical importance as render them useful and applicable to our pur- 
 poses. 
 
 While all metals are more or less susceptible 
 Cbemical BCtiOn. to the action of the secretions of the mouth, gold 
 and platinum are the least so, and of these two 
 platinum always withstands this influence and retains its color much 
 better than gold, which is due mainly to the fact that platinum is com- 
 monly used in the pure state, and gold in the alloyed state. 
 
 Each metal possesses a characteristic color, 
 Color. varying from the grayish-white of silver and plat- 
 
 inum to the muddy blue of lead; and from the rich 
 bright yellow gold to the dark red of copper; each of which is always 
 modified more or less by alloying. 
 
 Gold and platinum, however, possess a metallic luster and colors 
 which are in contrast more pleasing to the eye, and more in harmony 
 with surroundings, and which are the least susceptible to change by the 
 chemical action of the secretions. 
 
 Odor and taste are possessed by most metals 
 Odor attd taste* to such an infinitesimal extent that it is almost un- 
 necessary to mention them. Copper and zinc, 
 however, have the most definite metallic odor and taste, but as this is 
 apparent only when they are subjected to a temperature higher than 
 that of the body, and they are used only for the purpose of alloying, the 
 characteristic is of no especial importance. 
 
 All metals are capable of being reduced to a 
 TU$ibiHty* liquid state under the influence of heat, but the 
 
 melting point or degree of fusibility differs greatly, 
 and, like the color, is modified by alloying. The practical infusibility 
 of platinum of any thickness greatly facilitates some classes of work, 
 and the controlling at will of the fusing point of gold by alloying makes 
 the assemblage of innumerable parts and the art of soldering a com- 
 paratively easy and simple matter. 
 
 Malleability is the inherent property of a metal 
 malleability. which admits of its being hammered or rolled into 
 
 thin sheets without destroying the continuity of its 
 surface, and permits of its easy manipulation and adaptation. 
 
 Ductility is the property which admits of being 
 Ductility* drawn out into...lengths of a small diameter, such as 
 
 wire. 
 
13 
 
 Tenacity is the property of molecular resistance 
 
 tenacity. I-*^ tension, upon which depends the strength of the 
 
 metal. 
 
 In studying the accompanying table, it will be noted that gold, 
 
 while ranking first of tlie five principal metals most commonly used, 
 
 in malleability and ductility, ranks last in tenacity, but this, of course, 
 
 refers to pure gold, the tensile strength of which is greatly increased 
 
 by alloying with copper, silver or platinum. 
 
 Malleability. Ductility. Tenacity. 
 
 Rank I. Gold. Gold. Iron. 
 
 " II. Silver. Silver. Copper. 
 
 " III. Copper. Platinum. Platinum. 
 
 " IV. Platinum. Iron. Silver. 
 
 " V. Iron. Copper. Gold. 
 
 E^»)VS!CciS Processes. 
 
 The physical processes which mostly concern the dentist in the 
 manipulation of the metals to accomplish the necessary and desired 
 physical changes are those of soldering, welding, annealing, tempering, 
 and alloying, and a clear conception of each is of infinite importance 
 in their use. 
 
 Soldering is the process of uniting surfaces of 
 metal by fusion or superficial alloying. 
 
 Welding is the process of uniting surfaces of 
 melding. metal by molecular attraction under heat and pres- 
 
 sure. 
 
 Annealing is the process of softening or secur- 
 
 Unncaling. ing increased malleability, and as all metals expand 
 
 under the influence of heat, they in turn become 
 
 softened because of the separation of the molecules produced by this 
 
 expansion. 
 
 To accomplish this, they should be slowly heated to a cherry-red 
 and allowed to cool gradually, though plunging gold into water or 
 alcohol does not interfere with, and the latter seems to even increase, 
 its softness, while aluminum, fusing at a cherry-red heat, is best annealed 
 by coating each surface with oil, then igniting same and allowing it to 
 burn off. 
 
 Tempering is the process of hardening. In 
 tempering. gold, platinum, silver, copper, etc., it obtains as the 
 
 result of manipulation and consecutive working, due 
 to a molecular condensation ; while in iron containing carbon (steel) sud- 
 den thermal changes from various degrees of heat produce hardness in 
 
14 
 
 proportion to the quantity of carbon present, and the manner and 
 method of cooUng; while in some alloys the reverse condition obtains. 
 The accompanying table is indicative of the heat and color neces- 
 sary in tempering the various kinds of instruments used. (Essig: Am 
 Textbook, Pros. Dent., pp. 131.) 
 
 Temperature. 
 
 Color. 
 
 Use. 
 
 430 to 450 
 
 Fah. 
 
 Light yellow. 
 
 Enamel chisels. 
 
 470 Fah. 
 
 
 Med. 
 
 Excavators. 
 
 490 Fah. 
 
 
 Brown " 
 
 Pluggers. 
 
 510 Fah. 
 
 
 purple. 
 
 Saws, etc. 
 
 520 Fah. 
 
 
 Purple. 
 
 Wood-cutting tools. 
 
 530 to 570 
 
 Fah. 
 
 Blue. 
 
 Clamps, etc., when elas- 
 ticity is desired. 
 
 As alloys are a combination of two or more 
 mioying. metals, alloying is, of course, the process of com- 
 
 bining metals, and is of material significance be- 
 cause so few are now used in their pure state. Most metals enter freely 
 into combination with others, the alloy resulting frequently possessing 
 characteristics entirely different from those of any one of the component 
 parts. 
 
 They always fuse lower than the highest fusing, and often lower 
 than the most easily fusible, and in compounding them the least fusible 
 should usually be melted first in a clean crucible, and the others added 
 in relation to and in accordance with their fusibility, after first carefully 
 weighing out the proper proportions. 
 
 Alloys of gold, copper and silver can be melted and incorporated 
 almost simultaneously with comparative ease, while those containing 
 platinum or zinc are more difhcult. The former is usually added by 
 feeding it into the molten mass in thin, ribbon or foil form, while the 
 latter is best incorporated in the shape of brass or some other alloy of 
 known formula, because of the rapid volatilization of the rnetal. When 
 zinc is to be added in the pure state, the proper quantity should be 
 weighed, broken into small pieces and each piece coated with a film of 
 paraffin or wax, then quickly carried into the molten mass with pliers. 
 
 In this work it is necessary that one should be familiar with the 
 table of weight used for the purpose. 
 
 Troy Weight. 
 
 24 grains (gr.) = i pennyweight (dwt.). 
 
 20 pennyweights (dwt.) = i ounce (oz.). 
 12 ounces (oz.) =1 pound (lb.). 
 
15 
 
 Scale, 
 lb. oz. clwt. gr. 
 I == 12 = 240 ^^ 5760 
 
 I = 20 := 480 
 I = 24 
 
 Consideration of tbc metals. 
 
 The color, malleability, compatibility, slight 
 Gold. susceptibility to the chemical influences of the 
 
 secretions, and other qualities possessed by gold 
 make it easily the nearest approach to the ideal for universal use, and 
 while the higher artistic and esthetic tendency should always be to 
 avoid its conspicuous display in the mouth as much as possible, its 
 sphere of usefulness is unlimited. 
 
 Owing to its extreme softness in the pure or unalloyed state, how- 
 ever, it must be combined with other metals which will impart, to a 
 desired degree, the stiffness and strength necessary to withstand the 
 stress and wear imposed, without appreciably afifecting its other quali- 
 ties, and the ease with which it may be thus alloyed greatly enhances 
 its value. 
 
 In prosthetics the use of gold in the pure form is necessarily lim- 
 ited, being usually confined to work where a perfect adaptation is in- 
 dicated, such as backings for porcelain facings, individual bands, etc., 
 where it is to be afterward reinforced, and also as a solder for platinum 
 work. 
 
 In alloying gold the term karat is applied to 
 Hafat. the degree of fineness, and designates the propor- 
 
 tion of pure gold to the ratio of 24 parts. Thus 
 24 K. is virgin pure, while 18 K. is composed of 18 parts of gold and 6 
 of alloy. 
 
 Platinum is rapidly accjuiring aii extensive 
 Platinum. sphere of usefulness in dental art, and because of 
 
 its many admirable physical properties is second 
 only to gold. Those of malleability and practical infusibility render its 
 manipulation more or less easy, and have made possible the success of 
 porcelain work in the various phases of its present application; and it 
 withstands the chemical action of the secretions so much better than 
 gold as to rank first in compatibility with the tissues, which take most 
 kindly to it. It is also used extensively in alloying gold to which it im- 
 parts special properties. 
 
The use of iridium, the physical properties 
 
 Tridiunt. of which resemble, but are more refractory than 
 
 platinum, is confined to alloying with the latter, 
 
 the combination forming a tougher, harder metal, such as is indicated 
 
 in post material for dowel crowns and other instances requiring more 
 
 than ordinary strength. 
 
 For the purpose of reducing the fineness and 
 JTIIoys Of Gold. increasing the strength of gold, copper and silver 
 are mainly used as the alloy, usually in the propor- 
 tion of two parts of copper to one of silver. The former imparts hardness 
 and elasticity, and the latter pliability and strength, together with a 
 preservation of the original color which copper alone would change, 
 except where the desired fineness of the gold after alloying would not 
 admit of sufficient proportions of same to possess the requisite 
 strength, when platinum is added in small proportions to secure this 
 result. 
 
 For crown and bridge work, where strength and good color should 
 be combined and are prerequisites, the gold most generally used to the 
 best advantage is of about 22 K. fineness, which is necessary to resist 
 or secure immunity from the chemical action of the secretions, retain 
 its color and luster and withstand the stress; and is used in plate vary- 
 ing from 28 to 30 U. S. Standard Gauge. 
 
 The following are three common formulae used for this purpose: 
 
 21.6 K. No. 3. 21.6 K. 
 
 90 parts. Coin gold, 50 parts. 
 
 5 " Pure " 45 " 
 
 5 " " silver, 5 " 
 
 No. I. 22 K. 
 
 No. 2. 
 
 Pure gold, 22 dwt. 
 
 Pure gold. 
 
 " copper, I 
 
 " copper. 
 
 silver, 18 gr. 
 
 " silver, 
 
 Platinum, 6 gr. 
 
 
 
 The United 
 
 Coin Gold. 10, 
 
 was for man 
 
 plate which was used exclusively, but which is not 
 employed so extensively now because of the extreme hardness of gold 
 alloyed with copper alone, and of the objectionable reddish color, which 
 is not so pleasing to the eye, especially when contrasted by proximity 
 with the bright yellow of a pure gold filling. It may be used to good 
 advantage, however, in combination with pure gold and silver in proper 
 proportions, because of the definite knowledge of the proportion of 
 copper contained. 
 
Gold and platinum alloy is indicated wherever 
 
 Gold additional strength and springy elasticity are desired, 
 
 and PIcltinutn. such as clasps, and for stiffening the work over jjarts 
 
 which will be subjected to more than ordinary 
 
 stress, which property the addition of platinum, one part in 24, imparts 
 
 to the alloy. The following formula is used for the purpose: 
 
 Pure gold, 
 
 20 parts 
 
 Pure copper. 
 
 2 " 
 
 Pure silver, 
 
 I part. 
 
 Platinum, 
 
 I " 
 
 Platinized gold is a form of plate made by fusing 
 Platinized Gold. pure gold over one surface of platinum, which upon 
 being passed through the rollers then ])resents a 
 smooth, unbroken surface of each metal. It is much used in gold 
 work where infusibility seems desirable, and the presentation of a sur- 
 face of gold preferable to that of platinum. It is also frequently useful 
 as a backing for porcelain facings because of the advantage of control- 
 ling or preserving the color by placing next to the porcelain whichever 
 surface may cause the least, or produce the most desirable, change. 
 
 Solders. 
 
 The advent of porcelain work and the use of 
 
 Platinum Solder. high fusing "bodies" has created a demand for 
 
 a solder more infusible than pure gold, which was 
 
 previously used for the purpose, in order that joints so made would 
 
 not be affected by the high degree of heat necessary to fuse or vitrify 
 
 the body. 
 
 If there is absolute contact of the parts to be united, pure gold can 
 be successfully used, because if thoroughly and sufficiently fused, it be- 
 comes an integral part of the platinum by alloying with it; but in ex- 
 tensive work platinum solders are an advantage because of overcoming 
 the possibility of a change in the relation of the parts, caused by the 
 shrinkage of the porcelain, which is considerable. 
 
 Such solders are now prepared for the purpose, ranging from 10 
 to 40 per cent of platinum in combination with gold, but less than 20 
 per cent is of no advantage, and more than 25 per cent is unnecessary. 
 They may be easily compounded by thoroughly fusing the gold and then 
 feeding into the molten mass the desired proportion of platinum in foil 
 or ribbon form, after which it should be hammered out and remelted 
 several times to insure a thorough admixture. 
 
i8 
 
 Gold solders are alloys of gold so compounded 
 Gold Sold^fS* as to fuse slightly lower than plate of the same fine- 
 
 ness or karat; should be composed of the same 
 metals to preserve a close resemblance in color, and differ only in the 
 incorporation of a metal which will reduce the fusing point and impart 
 flowing properties. Thus a 20 K. solder, for instance, should fuse read- 
 ily on plate of the same K., otherwise it would not be a solder in the 
 sense of the meaning. 
 
 Zinc is mostly used for the purpose of reducing the fusibility and 
 imparting the requisite flowing properties, but should not be in pro- 
 portion more than i^ to 2 parts in 24; because if in greater quantity 
 the alloy would be rendered brittle, the strength thus diminished, and 
 the susceptibility to chemical influences when exposed to the action of 
 the secretions increased. Solder 01 a lower K. than is absolutely neces- 
 sary should never be used, because the lower the K., the greater the 
 affinity for oxidation and the susceptibility to chemical action; and in 
 consequence the seam of union and the surface exposed are always 
 rendered more or less conspicuous; hence it is desirable to begin with as 
 high a karat as possible, so that subsequent solderings may be made 
 with those of a degree of fineness which will aid in precluding this ten- 
 denc}^ And as the grades which are prepared for our use invariably 
 run lower than the karat stamp upon them, those of so-called 16 and 
 14 karat have but a very limited sphere of usefulness. 
 
 The following formulae give the average composition of the vari- 
 ous grades of dental solders: 
 
 22 K. Solder. 
 
 
 18 K. 
 
 SoId( 
 
 sr. 
 
 
 
 Pure gold, 22 
 
 dwt. 
 
 Pure gold, 
 
 
 18 dwt. 
 
 
 
 Brass, 2 
 
 (( 
 
 " silver. 
 
 
 3 " 
 
 
 
 Coin Solder. 
 
 
 " copper, 
 
 
 I " 
 
 
 
 Coin gold, 5 
 
 dwt. 
 
 Brass, 
 
 
 2 " 
 
 
 
 Brass, i 
 
 <( 
 
 16 K. 
 
 Sold. 
 
 sr. 
 
 
 
 20 K. Solder. 
 
 
 Pure gold, 
 
 
 II dwt.. 
 
 12 
 
 gr- 
 
 Pure gold, 20 
 
 dwt. 
 
 " silver, 
 
 
 3 " 
 
 
 
 Dorrance's alloy, 4 
 
 (( 
 
 " copper, 
 " zinc. 
 
 
 I " 
 
 12 
 12 
 
 gr. 
 gr. 
 
 14 K. Solder. 
 Pure gold, 14 dwt. 
 
 " silver, 5 " 
 
 " copper, 3 " 12 gr. 
 
 " zinc, I " 12 gr. 
 
19 
 
 As most of the scrap gold must or necessity 
 Compoundlnfl Solders, be of uniform karat or degree of fineness for the 
 reasons previously mentioned, and because of the 
 ease of securing the various karats of plate and solder by the dentist, 
 it is scarcely necessary to observe or be familiar with the method of 
 ascertaining and computing the fineness of gold to any extent, but as 
 it may often be desirable to compound solders it is well to know the 
 method of reducing scrap to the various karats used. 
 
 The following simple rule will enable anyone to reduce a given 
 quality of scrap to any desired fineness of solder. 
 
 Multiply the weight of gold Dy the karat and 
 
 Rule. divide by the desired karat. The difference between 
 
 the answer after dividing, and the original quantity 
 
 of gold, is the quantity of alloy necessary to be added. 
 
 c«,«.«i. Reduce 4 dwt., 3 gr., 22 K. gold to 18 K. 
 
 example. ^ , 
 
 solder. 
 
 4 dwt. + 3 gr. (original quantity) = gr. 99. 
 
 99 X 22 (origmal karat) = 2178. 
 
 2178 -^ 18 (desired karat) = 121. 
 
 121 — 99 (dif. bet. result and orig. quantity) = 22. 
 
 Ans.: 22 gr. of alloy should be added. 
 For this purpose the alloy should of course contain copper, silver 
 and zinc, and may be secured in the most convenient form in the shape 
 of known formulae, such as brass, Dorrance's alloy, or silver solder. 
 
 Brass is composed of copper and zinc m 
 Brass. proportions suitable for the purpose intended, us- 
 
 ually varying from equal parts of each to 70 of cop- 
 per and 30 of zinc, and owing to its close resemblance to gold in physical 
 properties and characteristics is much used in various lines of work. 
 When used as an alloy for gold in compounding solders, its definite 
 formula should of course be ascertained, and that composed of copper 
 50, zinc 50, is the best for the purpose. 
 
 Dorrance's alloy, suggested by Dr. W. H. Dor- 
 Dorrance'S fliloy. ranee, is used extensively in reducing gold to solders, 
 being a combination of the three principal metals 
 used, in good proportions, with copper in the preponderance. The fol- 
 lowing is the formula: 
 
 Copper, 6 parts. 
 Silver, 2 " 
 Zinc, 4 " 
 
20 
 
 Silver solder is an allov of copper, silver and zinc, 
 
 SilPCr Solder. with silver in the greatest proportion, and is much 
 
 used in the making of gold solders, as the alloy, as 
 
 well as being an economical hard solder for various lines of work where 
 
 brass and German silver are used. A common formula is : 
 
 Silver, 6 parts. 
 C;opper, 3 " 
 Zinc, I part. 
 
 German silver is used to some extent in tempo- 
 German $WvtT, rary work of all kinds, such as dowels for temporary 
 crowns and bands for matrices, etc. It is com- 
 posed of copper and zinc, with the addition of nickel, which mcreases 
 the fusing point and gives a harder, tougher alloy. 
 The following formula is much used: 
 
 Copper, 50 parts. 
 Zinc, 30 " 
 Nickel, 20 " 
 
 Fusible alloys are those in which the lower fusing 
 fusible Jinoys. metals are combined, such as lead, tin, bismuth, 
 antimony, and cadmium, and arc intended for use 
 m making dies and counterdies for swaging in crown-work, and for the 
 purpose ot obtaining models direct from plaster impressions, or from 
 the mouldine compounds suggested by Dr. George W. Mellotte, and 
 composed of potter's clay and glycerine. The extreme fusibility of 
 these alloys depends to a great extent upon the proportion of bismuth 
 incorporated, and varies accordinglv. The following are formulae of 
 the various known alloys of this nature: 
 
 Wood's Alloy. Newton's Alloy. 
 
 Bismuth, 8 
 
 Lead, 5 
 
 Tin, 3 
 
 Fusing point, 200° F. 
 
 Hodgen's Alloy. • 
 Bismuth, 8 
 
 Lead, 5 
 
 , Tin, 3 
 
 Antimony, 2 
 
 Fusing point, 224° F. 
 
 Bismuth, 
 
 
 5 
 
 
 Lead, 
 
 
 4 
 
 
 Tin, 
 
 
 2 
 
 
 Cadmium, 
 
 
 I 
 
 
 Fusing point. 
 
 140° 
 
 F. 
 
 Rose's Alloy. 
 Bismuth, 8 
 Lead, 8 
 Tin, 3 
 Fusing point, 174° 
 
 F. 
 
21 
 
 Mellotte's Alloy. Ordinary Formula. 
 
 Bismuth, 8 Lead, i 
 
 Tin, S '^^"' ^ 
 
 Lead, 3 Bismuth, 2 
 
 Fusing pomt, 200"^ F. 
 
 R. C. Brophy's Alloy. Grouse's Alloy. 
 
 Bismuth, 3 Bismuth, 8 
 
 Lead, 2^ Lead, 5 
 
 Tin, 2V2 Tin, 5 
 
 Fusing point, 240° F. Cadmium, i 
 
 Fusing point, 190^ F. 
 
 Molyneaux's Alloy. 
 Lead, 3 
 
 Tin, 2 
 
 Cadmium, 2 
 
 Bismuth, 5 
 
 Fusing point, 140° F. 
 
 The lower fusing of these various well-known alloys may be cast 
 directly into plaster, gutta percha or modeling compound impressions, 
 without waiting for them to dry out, and Dr. Grant Molyneaux recom- 
 mends that such impressions should be dipped in water just before 
 pouring with his alloy to secure the best results. 
 
 While there is probably but a very limited use 
 
 Soft $Old«r, for soft solder, it may sometimes be indicated in 
 
 temporary work. The ordinary tinner's solder is 
 composed of equal parts of tin and lead, though any of the fusible alloys 
 will answer the purpose equally as well. 
 
 It frequently occurs that the accumulation of 
 
 Refining Gold. scrap gold in the laboratory may become so con- 
 taminated with base metals, from contact and from 
 the file, that it could not well be used over again by melting and rolling 
 into plate, which convenience sometimes requires, without being first 
 subjected to some simple process of refining. 
 
 When the scrap is composed mostly of a known degree of fineness, 
 this may be quite easily accomplished without resorting to the chemical 
 process, by what is known as the roasting method. 
 
 This consists of placing the scrap in a clean crucible with plenty 
 of borax, and applying heat until a perfect fusion is reached, when 
 small pieces of potassium nitrate (saltpetre) should be consecutively 
 added. 
 
This oxidizing agent furnishes usually sufficient oxygen to oxidize 
 all base metals, which oxides are absorbed by the borax, and if kept 
 up long enough will result in so materially refining the gold as to per- 
 mit of its being annealed, rolled to the desired thickness and used over 
 again. 
 
 Recovering ana Refiniitd Ulaste Goll 
 
 While it is very probable that the average dentist will have neither 
 the time, inclination nor facilities for recovering the waste gold which 
 daily finds lodgment in, or becomes attached to, sweepings, rugs, carpets, 
 disks, strips, etc., yet the method usually employed in obtaining and re- 
 fining it may be of some general interest. 
 
 The sweepmgs and such various articles as may contain gold are 
 first placed in a suitable vessel, and subjected to a degree of heat in a blast 
 furnace which will reduce them to ashes and residue, after which this 
 latter is then Unely pozvdcrcd. 
 
 The gold, together with its impurities, can now be separated from 
 most of the ash, carbon, sand, etc., by a mechanical process of ivashiiig, 
 in which, because of the high specific gravity of the metallic masses, the 
 latter will seek the lowest point, allowing the residue to remain on 
 top. 
 
 The gold may now be extracted from the remaining mixture of 
 heavy material by the following method : Treat with nitro-hydrochloric 
 acid (aqua regia), heat gently, agitate occasionally, and then allow the 
 mixture to stand for a few hours. 
 
 The solution is now evaporated until all free acid has been expelled, 
 when it is allowed to cool, and alcohol and potassium chloride are added, 
 which precipitates any platinum that may be present. 
 
 The gold may now be precipitated from the filtered solution by add- 
 ing ferrous sulphate, c.p., or heating it with a solution of oxalic acid, 
 when the precipitate, a fine brown powder, should be washed with dis- 
 tilled water, placed in a graphite crucible and thoroughly fused with 
 potassium nitrate (saltpetre), or borax, as previously indicated. 
 
 The molten metal may be then poured from the crucible into a pre- 
 viously warmed and oiled mould, when an ingot of pure gold is obtained, 
 which may be alloyed, if desired, and rolled out to suitable thickness 
 for use.* 
 
 *The foregoing is intended only as the essence of dental metallurgy, tinctured with practical 
 application in its relation to crown and bridge work. I have quoted freely from Mitchell's Dental 
 Chemistry, Hodgen's Dental Metallurgy, and the American Textbook of Prosthetic Dentistry. 
 edited by Dr. C. J. Essig, and am indebted to Dr. J. P. Buckley, of Chicago, for suggestions 
 and assistance. 
 
Soldering. 
 
 CHAPTER III. 
 
 Essential Requirements: Cleanliness; Acid Bath. Flux; Borax; Method of Usinj 
 Parr's Fluxed Wax, Liquid Soldering Fluids. Apposition; Requirements 
 and Method of Obtaining. Uniform Heat; Application and Require- 
 ments. Difficulties Encountered: "Balling Up," Shrinkage, Base 
 Metals, Gravity, Fracturing Porcelain Facings, Soldering Block 
 Teeth. Manipulation: Soldering Without Investment. Flame 
 Blow-pipes. Soldering With Investment, Gold Solder- 
 ing, Pure Gold Soldering, Platinum Soldering, Oxy- 
 Hydrogen Blow-pipe, Cooling After Soldering, 
 To Prevent Unsoldering. Sweating Process. 
 Autogenous Soldering. Soft Soldering. 
 
 In its application to dentistry soldering has rapidly assumed the 
 significance of an art of much greater importance than ever attained 
 by those presupposed past masters — the gold and silversmiths. This is 
 readily proven by the ease with which the process is now executed in 
 the consecutive union of a multiplicity of parts and the building or 
 restoration of contour, as compared with the work along similar lines 
 confined to their province. 
 
 The ease and dexterity with which such results may now be ob- 
 tained by the more skilful, however, compared with the expressions of 
 •doubt and even dread manifested by others, followed by such discourag- 
 ing failures as the burning or fusing of the parts, or the fracturing of 
 porcelain facings, leads to the very natural conclusion that in sucli 
 instances the lesson has not been properly learned, and that the subject 
 merits and demands more thoughtful consideration and study, and more 
 persevering application than is usually accorded. 
 
 To this end the dentist cannot too closely apply himself in the effort 
 to become sufficiently skilled as to render the procedure one of simplicity 
 and ease, together with reducing to a minimum, or eliminating, all attend- 
 ing dangers of and liability to, accident, which in this, the physical 
 
24 
 
 process of uniting surfaces of metal by fusion or superficial alloying, 
 will invariably follow a comprehensive knowledge of the fundamental 
 requirements, and a close observation of all of the essentials concomitant 
 with success. 
 
 €$$enti(il K^^uirements. 
 
 These important considerations are cleanliness, flux, apposition, 
 and uniform heat, and unless clearly understood from a practical stand- 
 point, the process involved, while perhaps sometimes successfully ac- 
 complished, is necessarily followed in a more or less perfunctory manner, 
 in which case the operator becomes simply an automaton. 
 
 The thorough removal of all oxidation and de- 
 
 0kaniin($$. posits of foreign nature from the surfaces to be 
 
 united is highly necessary in order that the solder 
 
 may become thoroughly attached or incorporated, so that the element of 
 
 strength may be insured in the union. This may be secured by scraping 
 
 or filing the surfaces, or by treating them with an acid solution. 
 
 For this purpose sulphuric or hydrochloric acid, 
 J\i\A Ball). diluted with an equal proportion of water, is used, 
 
 into which the parts are immersed for a few 
 moments to dissolve and remove all foreign substances. 
 
 Sulphuric acid is preferable, and for large work 
 Sand Ball). should be contained in a porcelain evaporating dish 
 
 of proper dimensions, as heat materially increases 
 its cleansing properties. The dish should then be placed in a shallow 
 sheet iron bowl partially filled with sand and placed upon a tripod over 
 an alcohol or Bunsen flame, by which means the parts may be boiled, if 
 necessary. As the fumes thus given off are more or less injurious when 
 inhaled, some provision must be made for carrying them away, which 
 may be quite easily accomplished by attaching a hood to a gas pipe and 
 permitting the latter to pass through a hole in the window at some acces- 
 sible point (Fig. 17). 
 
 For small work a much more convenient method is to freshly mix 
 the solution each time by pouring info a small quantity of acid an equal 
 proportion of warm water, when the chemical reaction will generate heat 
 enough to thoroughly clean the parts, after which it may be thrown out. 
 For metal work only, where no porcelain is used, this solution may 
 be saved by placing it in a large-mouthed bottle and used indefinitely 
 and effectively when cold by first heating the parts to be cleaned and 
 then plunging them into the acid. 
 
25 
 
 After removing- the work from the bath, it must always be thor- 
 joughly washed in clean water to so dilute the acid as to remove all traces- 
 
 Fiq.l7. 
 
 of it before heating in the flame, because if this is not carefully done, and 
 any traces of acid should remain, the formation of the salts of the baser 
 metals which is facilitated by the heat will at once preclude the possibil- 
 ity of soldering until again treated with acid and this precaution observed. 
 
 Tlux. 
 
 As the affinity for absorbing oxygen from the atmosphere, which- 
 nearly all metals possess, is increased by heat, the application of it inci- 
 dent to the process of soldering causes the exposed surfaces to become 
 rapidly oxidized, in consequence of which it is necessary to preclude the 
 possibility of such tendency and preserve the cleanliness of the parts in 
 order that the solder may not be prevented from readily fusing and be- 
 coming alloyed. 
 
 Substances are used for this purpose which, when fused over such; 
 surfaces, keep them clean and free of oxidization, and aid in the fusing and 
 alloying. It is equally necessary that the solder as well as the surfaces of 
 metal be thus treated, because, being a lower grade alloy, it is more easily 
 oxidized. When not so treated the neglect may not infrequently be the 
 cause of much obstinacy in fusing, demanding a greater degree of heat 
 than otherwise necessary. 
 
26 
 
 ^. Borax is most generally used for this purpose 
 
 B0f4X* ^n<i meets the requirements in every respect, but 
 
 the common practice of using it in dry powdered 
 form, in far greater quantities than necessary, is to be most vigorously 
 condemned, because when first heated it expands to such extent as to not 
 infrequently split the investment and change the relation of the parts; 
 may even flake or deface the porcelain if it should come in contact with it 
 by fusing upon it; always displaces the solder, and usually results in the 
 presentation of a pitted surface. 
 
 To prevent this and secure the best results, it should be mixed with 
 clean water to the consistency of a thin paste, and applied, before heating 
 the parts, with a small camel's hair brush, which admits of its application 
 to the particular surfaces in the proper and necessary quantity. 
 
 Owing to the tendency to crystallize, however, it is difficult to pre- 
 serve such consistency, but this may be facilitated by preparing and 
 
 Fiq.l8. 
 
 keeping it in a glass-covered dish, where it may be also kept clean and 
 free from dirt, which is eminently desirable. (Fig. i8.) 
 
 This is a hard wax, containing an admixture of 
 PaiT*$ TlUXCd max. borax, which is much used, and is a convenient 
 form of flux, as the wax burns out, leaving the 
 borax deposited upon the surfaces in small proportions. 
 
 Liquid soldering fluid is now being extensively 
 
 CidUid used in dentistry, and has been by jewelers for a num- 
 
 Soldcriltfl fluid. ber of 3'ears, and is the best, cleanest, most desirable 
 
 and convenient flux for our purpose. It is a saturated 
 
 solution of equal parts of borax and boric acid in water, and can be more 
 
 easily and readily applied with a camel's hair brush or small piece of 
 
 wood in proper quantity to a better advantage than any other. 
 
 In all instances, however, the flux should be applied before heating 
 the object to be soldered, in order that it may be placed in or carried to 
 every portion and- surface of the metal upon which the solder should 
 flow iri securing union. This is not always possible if applied to the 
 heated case, in which instances powdered borax is preferable. 
 
2.7 
 
 To facilitate the union between the parts, the edges or surfaces 
 should always be in absolute contact, or as nearly so as possible, so that 
 there may be strength in the joint, and no impediment offered to the 
 solder in flowing freely over the surfaces to be united. 
 
 In case the proper relation necessary to be sustained will not admit 
 of contact, it should then be secured by filling in between such edges or 
 surfaces, thus bridging them over with small pieces of the metal of 
 which the work is being constructed. This is usually best accomplished 
 with gold or platuium wire or plate, or some of the foil or crystal golds, 
 the latter being preferable because of their thickness, which should be 
 fitted or packed into place before the case is heated. 
 
 UNiform 1)eat 
 
 The application and proper manipulation of heat In securing the best 
 results is an important feature, but because of the under-valuation or 
 over-estimation of the requirements is frequently the means of much 
 discouraging and unnecessary labor, yet when properly applied with the 
 former prerequisites observed, the entire procedure is infinitely simple. 
 
 In this connection it must be remembered that, as the process con- 
 stitutes the alloying of the parts, the surfaces to be united must be freely 
 exposed, and then brought to a degree of heat exceeding, or at least 
 equal to, the fusing point of the solder before union can obtain. 
 
 DiffictiUies ENCOHNterca. 
 
 If this degree of uniformity is not scrupulously observed, and the 
 heat be directed upon the solder before the parts are equally and suf- 
 ficiently heated to permit of alloying, the aggravating annoyance of "ball- 
 ing up^' is invariably the result. 
 
 This tendency of the solder to assume globular 
 
 ^'Balling Up." form w^ith more or less obstinate persistency is 
 due only to the difference between the size of the 
 object to be soldered and the relative degree of heat required by it, 
 ag compared with the small quantity of solder used and its consequently 
 greater fusibility. If much time be thus consumed the baser alloy con- 
 tained in the latter may be burned out, the loss or depletion of which will 
 increase the fusibihty and decrease the flowing properties to such extent, 
 perhaps, as not infrequently to cause the melting of the parts. 
 
28 
 
 As this is obvious, and since the affinity of one metal for combining 
 with another is increased by heat, it is only necessary to first raise the 
 temperature of the higher fusing parts equal or near to the melting 
 point of the most fusible, when very little further heat well directed upon 
 both simultaneously will result in perfect union with little or no effort, 
 and as the solder will follow the heat or flow in the direction of the great- 
 est degree of temperature, it can be controlled accordingly. 
 
 As the shrinkage of solder increases in proper- 
 SbrinRage. tion to the quantity of baser alloy incorporated, and 
 
 manifests itself to such an appreciable extent in gold 
 work, it is imperative to use the utmost precautions toward preventing 
 the possible change in the relation of the parts which might thus ensue, 
 and which may not infrequently result in jeopardizing the fit and adap- 
 tation. 
 
 To preclude this possibility it is necessary to observe the require- 
 ments of apposition and contact very closely, and in more or less exten- 
 sive work it may be further prevented by soldermg each piece separately 
 first, so that in the final assemblage of the parts as little solder may be 
 used and carried to the fluid state as is immediately required to secure 
 union and strength. Thus very large cases should be soldered in sections. 
 and afterward united. 
 
 Perhaps paramount among the difficulties most: 
 
 Tractnrlnd of frequently experienced is the checking or fracturing 
 
 Porcelain TacingS. of porcelain facings, but this, while seemingly and/ 
 apparently unavoidable, is in nearly all instances 
 due to the most' flagrant negligence, in so far as soldering is concerned. 
 
 In this connection it is necessary to consider the fact that a porce- 
 lain facing constitutes and presents two distinct substances, the mineral 
 and the metal — the porcelain and the pins — each of which possesses phy- 
 sical properties which are affected very differently by the heat to which 
 they are subjected. 
 
 The mineral, absorbing heat very slowly and gradually, retains it 
 for a considerable length of time, while the metal absorbs it readily, and 
 gives it off or cools with equal rapidity ; consequently, in the process of 
 soldering, the utmost care must be exercised in applying the heat so 
 gradually and uniformly from the very outset that the porcelain, which 
 is a friable material, will receive it either preceding or at least simultane- 
 ously with the platmum pins, in order that the expansion which takes 
 place in each may occur evenly and uniformly. It is invariably this uneven 
 expansion, wherein that of Ih^^ porcelain is not sufficient to accommodate 
 that of the pins, which causes the fractures occurring across the surface of 
 the facing, always radiating from the pins. To various other reasons^ 
 
29 
 
 however, may sometimes be attributed this difficulty, but the percentage 
 is very small as compared with that of uneven expansion. 
 
 Such other cases may be from impingement due to the shrinkage of 
 the solder and augmented by too close proximity of parts with each other 
 to accommodate this shrinkage; from overhanging edges of backings, 
 vv'hich in contracting necessarily impinge upon the edges of the facings, 
 causing innumerable small checks along such edges; to perforating the 
 backings with openings much too large for the reception of the pins, 
 thus permitting the solder to run in between backing and facing; or to 
 carelessness in bending the pins (to retain the backings), in such manner 
 as to produce a constant strain on the porcelain immediately surrounding 
 their attachment. As a proof that it is either uneven expansion or 
 faulty adaptation of the backing, it is noticeable that facings seldom if 
 ever check in porcelain work where they are subjected to even a much 
 higher degree of heat. 
 
 Where there has been extensive resorption of 
 Soldering tissue it will sometimes be desirable to use what are 
 
 Block known as gum blocks. Because of the curve of these 
 
 €C(tb. blocks there would be more or less liability of frac- 
 
 ture, even in skilful hands were a single backing to 
 be used for the whole block. By a very simple method, however, blocks 
 of three and even four or more teeth may be safely utilized, thus avoiding 
 the unsightliness an<l uncleanliness of joints which would result from 
 vising single gum teeth. This absence of joints is especially desirable 
 when restoring the anterior upper teeth, and in replacing the four in- 
 cisors a most artistic result may often be attained with a single gum 
 block; In using these blocks each tooth in the block should be backed 
 separately, the backings being so placed that they would not absolutely 
 touch. In adapting the blocks to the piece to which they are to be attached, 
 care should be employed to so fit them that the minimum of solder will be 
 required to effect union. There will be no danger of cracking the block 
 during this last procedure, because the base to which attachment is made 
 sliould afford ample resistance to the slight shrinkage of the solder at the 
 bases of the separate backings. 
 
 Another not unusual occurrence during the 
 
 Base IttrtalS. process of soldering is the appearance of small holes 
 
 or perforations on the surface of the metal. These 
 are usually due to the presence of some of the baser metals, which may 
 become attached by contact with the dies in swaging; from a file contain- 
 ing same, or from the work bench, and can only be avoided by always 
 carefully treating the piece to an acid bath immediately preceding each 
 application of heat. 
 
:30 
 
 ■: " In extensive work it is always desirable to 
 
 Gf^Vity* observe the laws of gravity as much as possible, for 
 
 while it is true that the solder will follow the heat, 
 and its flowing may be so controlled in a measure, when used in con- 
 siderable proportion its weight will naturally cause it to seek the lowest 
 point ; hence it frequently becomes necessary, especially in large cases 
 for the anterior part of the mouth, where the curvature is greater, to 
 change the position of the case as the soldering progresses in order to 
 retain the mass in the desired location when in the fluid state. 
 
 manipiilation. 
 
 Closely following a consideration of the requirements and difficul- 
 ties encountered in this work is the importance of practical manipulation 
 in its various phases, the proper execution of which renders the proce- 
 dure easy and simple. 
 
 In soldering bands, caps, and cusps, where no 
 
 Soldering investnient is necessary to sustain the relation of the 
 
 mitbOUt Tnvcsttntnt* parts, the work is more easily accomplished because 
 
 of the greater opportunities for securing uniformity 
 
 of heat, and can usually be done in the flame of an alcohol lamp or Bunsen 
 
 burner with ease; but the manner of holding the object in the flame, and 
 
 the material of which the instruments for the purpose are made bear 
 
 materially upon the dexterity and simplicity with which the procedure 
 
 may be accomplished. 
 
 "^ As dififerent parts of the flame vary in the degree 
 
 TIatne. of intensity of heat, it is of importance that the object 
 
 be held in a proper relation to the same in order that 
 the soldering may be more easily accomplished. The flame consists of 
 an outer sheath varying in color from a dark blue at the base to a yellow* 
 ish white at the point, which envelops a central cone of light bluish eolor> 
 at the summit of which the greatest degree of heat is present (Fig. 19). 
 
 Fine-pointed pliers should invariably be used and the object should 
 be held at a point as remote from the surface to be soldered as possible, 
 so that the pliers will not absorb the heat. Because of this tendency, 
 steel instruments should seldom be used, while those made of nickel, or 
 its alloy, or of steel with fine platinum points answer the purpose much 
 better because they absorb so little heat that they may be held comfort- 
 ably in the hand. 
 
 In soldering platinum with pure gold the use of flux is not impera- 
 tive, for the reason that both metals are pure and devoid of alloy, which 
 
31 
 
 greatly diminishes their susceptibiUty to oxidation, and the ordinary 
 mouth blowpipe (Fig. 20) is all that is necessary; while platinum solder 
 up to twenty-five per cent, can be successfully used with the "combina- 
 tion^' blowpipe and bellows (or compressed air) (Fig. 21), or may be 
 
 equally well done with the gasoline blowpipe, a successful and convenient 
 style of which includes a burner and is manufactured by Dr. R. C. Brophy^ 
 of Chicago, 111. (Fig. 22), or small pieces of platinum work where the 
 contact and relation can be sustained by proper adjustment, and where 
 
 riq.20, 
 
 no investment is .necessary, can very often be soldered in the electric 
 furnace with much convenience. 
 
 Where the case is necessarily invested the 
 Soldering process is usually considered as a somewhat more 
 
 Ulitb Investment.. difficult and arduous task, which for very , good 
 reasons it unfortunately often proves to be, the prin- 
 cipal one of which is a failure to properly and adequately heat the entire 
 case before attempting to solder. 
 
It should first always be placed upon a Bunsen or gasoline burner 
 and allowed to remain sufficiently long to become gradually and thor- 
 oughly heated, which may be hastened, if necessary, by applying and di- 
 
 Ficj.22. 
 
 recting the heat with the "brush" flame from the blowpipe, to the under 
 ;surface in conjunction with the burner. Then, when it shall have reached 
 a temperature indicated by a red heat, the solder should be consecutively 
 
33 
 
 applied in fairly good sized pieces, which, with the burner from beneath 
 to preserve a uniform heat, and a "pointed" flame from the blowpipe 
 directed upon the parts, will easily and quickly accomplish the object 
 sought without useless expenditure of effort or energy. 
 
 The fusing and flowing of the solder in the desired location and 
 direction may occasionally be facilitated by the use of a fine pointed steel 
 instrument when in^the partially fused op plastic state, after which only 
 heat sufficient to solidify the mass until a smooth surface obtains should 
 be applied. 
 
 In fusing gold solder of any grade the require- 
 GoW Soldering. ments in the degree of heat so far as the blow- 
 pipe itself is concerned are generally greatly over- 
 estimated. If the case is first properly heated, the combination 
 blowpipe controlled by the mouth easily furnishes all that is necessary. 
 and is preferable and safer, as the danger attending the burning of the 
 parts is always increased by the use of the bellows, because the control 
 is not so perfect. 
 
 To blow a continuous flame with the mouth blowpipe is a valuable 
 accomplishment and can be acquired with practice by nearly any one. 
 
 In platinum work, where the danger of burning 
 Pure is eliminated, and the requirements of heat are 
 
 Gold Soldering. increased by the use of pure gold as solder, the bel- 
 lows will, of course, be found convenient and useful, 
 though even then the skilful manipulation of the mouth blowpipe will 
 accomplish the work. However it may be obtained, heat enough to 
 thoroughly fuse the gold until it becomes alloyed zcith the platinum, so 
 as to occupy no apparent space except that in the immediate joint, is 
 .absolutely essential to successful results in this work. 
 
 In small cases where a laige investment is not 
 
 Platinum indicated, platinum, solders up to twenty-five per 
 
 Soldering. cent, may be fused with the bellows or compressed 
 
 air, but the necessary degree of heat to thoroughly 
 
 and easily fuse them can, of course, be best obtained from the oxy-hydro- 
 
 gen flame, which is indicated always in extensive work. 
 
 The use of an oxy-hydrogen blowpipe is regarded 
 Oxy-1)ydrogcn by many as being somewhat complex and expensive. 
 Blowpipe. but is in reality most simple and comparatively inex- 
 
 pensive. In manipulating one the illuminating gas 
 should be turned on first and ignited, and then the nitrous oxide valve 
 opened very slowly and gradually, until perfect combustion is obtained. 
 The case should be first thoroughly heated with the brush part of the 
 flame, after which it is necessary to bring the point of the central cone in 
 
34 
 
 contact with the surfaces to be united, as this is the heat-producing por- 
 tion. The soldering may then be accomplished with ease. 
 
 The extreme heat and incandescence, however, is very trying to the 
 eyes, and a pair of smoked glasses will be found most conducive to 
 success and comfort. Fig. 23 illustrates a simple and inexpensive ap- 
 paratus for this work, manufactured by L. J. Mason & Co., of Chicago, 
 Illinois. 
 
 When the soldering has been completed, the 
 pooling After case should remain over the flame for a few mo- 
 
 SOldcring. ments to prevent too rapid cooling and the conse- 
 
 quent sudden contraction or shrinkage, after which 
 the flame may be turned off and the case allowed to stand until cool enough 
 
 nq.23. : 
 
 to handle, when it may be then removed from the investment, cleaned in 
 acid, and finished. 
 
 In cases where an investment is not indicated 
 
 Co Present it is frequently desirable "to observe some precau- 
 
 (Insoldcring. tions to avoid the unsoldering or re-fusing of parts 
 
 previously united, which is usually accomplished by 
 
 the mere presence of the investment itself when such is used. This may 
 
 always be very easily prevented by coating or treating such surfaces with 
 
 crocus (ferric hydrate), or a liquid solution of whiting, or plumbago, in 
 
 water or alcohol. . 
 
 The not infrequent occurrence or presence of 
 
 Sweating small perforations in the surface of the work makes 
 
 Process, it often necessary to resort to some me?ins of filling 
 
 themi in. This is best accomplished usually by what 
 
 is known, as the sweating process, which simply implies bridging them 
 
 over. with sojder. 
 
 This may apply to cases requiring investment or not, and the pro- 
 
35 
 
 cedure in either instance indicated is to first thoroughly clean the parts 
 and then fit or burnish into the openin.g a piece of pure gold plate or foil 
 of suitable dimensions, which may be held in place by holding the work 
 in a favorable position to sustain it, or attaching it by the fusion of the 
 flux. A piece of solder somewhat larger than the perforation should then 
 be placed in position, covering same, and likewise held in place, and then 
 heat uniformly applied until the solder becomes firmly attached without 
 complete fusion. In small perforations solder alone will acconiplish this 
 end, without the use of a support of pure gold or other metal. 
 
 Autogenous soldering is the process of uniting 
 JIUtoaenous Soldering, surfaces by immediate inter-fusion, without the use 
 
 of a lower grade alloy, and while it has no decided 
 advantages, excepting that a joint so made is not increased in stiffness or 
 thickness, and the appearance of a seam of solder is avoided, it is quite 
 easily accomplished in uniting bands and attaching solid cusps to them, in 
 the execution of which the surfaces must be perfectly approximated, re- 
 tained closely in contact, properly fluxed, and held in t^ie flame until union 
 is accomplished by superficial fusion. By a little practice one may become 
 quite skilful, and joints so made usually possess every element of 
 strength. 
 
 While soft soldering is not to be generally com- 
 Soft Soldering. mended, it is sometimes indicated in emergency 
 
 cases, where some strength in the union of the parts 
 is required, as in temporary crowns, etc. For such purposes a solder 
 composed of equal parts of tin and lead, or any of the fusible alloys, may 
 be used, either with a soldering iron or bv placing them upon an asbestos 
 pad and directing the flame of the burner upon them until the solder 
 fuses. A convenient flux for this Avork is made by gradually adding 
 pure zinc to hydrochloric acid until the chemical action subsides or the 
 acid refuses to take up more, thus making a solution of zinc chloride, 
 when it may be filtered and is ready for use. .■ ' "'i 
 
Investing ana Investment nidterials. 
 
 CHAPTER IV. 
 
 Object of Investing. Requirements of Material. Materials Used. Physical Prop- 
 erties. Models. Requirements of an Investment. Preparing Case for 
 Investment. Hard Wax. Adhesive Wax. Investing. Small Cases. 
 Extensive Cases. Precautions. Removing Wax. Prepa- 
 ration of Investment. Drying and Heating, Pre- 
 pared Compounds. 
 
 One of the most important features to be observed in connection 
 with the process of soldering is the proper investment of the case, the 
 object of which is to sustain the relation of the parts and preserve a uni- 
 formity of temperature during and succeeding the application of heat. 
 
 By investing the parts the uneven or too rapid 
 
 Object heating or cooling of porcelain facings and the con- 
 
 Of Tnvesting. sequent attending dangers are obviated, and any 
 
 possible change in the individual relation of the parts 
 
 while being united or assembled is entirely overcome. 
 
 A suitable compound for such purposes should 
 
 KcquireincntS possess the essential properties of crystallization, in- 
 
 OT materiaU fusibility, free conductivity and strength, and should 
 
 neither shrink nor expand appreciably during the 
 
 lieating process. 
 
 Many substances may be used in combination 
 materials Used. with plaster of paris, which is necessarily the basis 
 because of imparting the property of crystallization, 
 and which must be incorporated to the extent of at least 50 per cent. 
 
57 
 
 The remaining- proportion may be then composed of such materials 
 as will, by virtue of their characteristics and physical properties, meet such 
 requirements. The following are serviceable : 
 
 Powdered Silex, Pulverized Pipe Clay, 
 
 Fine Asbestos, Powdered Fire Brick, 
 
 Beach Sand, Magnesium Sulphate, 
 
 Marble Dust. Pumice Stone. 
 
 A combination of any of these ingredients in varying proportions 
 with the proper quantity of plaster will usually possess the necessary 
 qualities, excepting pumice stone, which, because of its low fusibility and 
 inherent tendency to expand, should never be used, and asbestos in large 
 proportions, which, while serving to hold the mass together, when mixed, 
 is objectionable because of its extreme low conductivity. 
 
 The property of free conductivity is important 
 
 Physical Properties, because this materially lessens the time consumed in 
 
 heating the case, by absorbing and distributing the 
 
 heat more rapidly and evenly, and by thus retaining it the better the 
 
 soldering is facilitated, and the liability of checking porcelain facings 
 
 diminished. 
 
 A tendency on the part of any compound to expand and crack open 
 vv^hen subjected to the influence of heat usually indicates that the texture 
 is too fine to admit of the rapid evaporation of th^ moisture, and as 
 possible displacement of the' parts and checking of facings is thereby 
 promoted, the use of such material is objectionable and unsafe. 
 
 By the addition of a coarser ingredient to the compound, however, 
 this fault may be overcome, and a small quantity of fine shredded asbestos 
 will also frequently eliminate the objection in a measure, without greatly^ 
 reducing the property of conducting heat. 
 
 While, generally speaking, all models should h& 
 models. made of plaster alone, because of thus possessing- 
 
 greater strength, smoother surfaces and more accu- 
 rate and definite outlines, while offering no impediment to successful 
 soldering when properly prepared, there may be frequent indications for 
 making them of investment material. 
 
 In such instances a material which will shrink or expand appreciably 
 is decidedly objectionable, and the characteristics of that used for sucH 
 purposes must be of known quantity, for the reason that a degree of in- 
 accuracy in the relation of the parts and their proper adaptation 
 may result. 
 
 Where such a model seems indicated and desirable, and especially for 
 the purpose of the final assemblage of the parts in extensive cases, a. 
 
-38 
 
 smooth, well-defined surface may be secured by first pouring a small 
 quantity of thin, well-mixed plaster into the impression, then inverting 
 the cup until all surplus runs out, leaving only a thin surface coating, 
 when by being immediately filled with the investment material, a model 
 is obtained possessing a veneer of plaster. 
 
 As the object of investing is to hold the parts in 
 
 Requirements their proper relation and afford protection to the 
 
 Of an Investment. facings, it is but necessary that the investment should 
 
 be only large enough to accomplish this end. 
 
 Any surplus in excess of merely meeting such a requirement increases 
 
 the heat necessary and adds to the labor involved in the process of solder- 
 ing, without any possible advantage. 
 
 In assembling the individual parts on the model, 
 Preparing Base for some means should be observed which will tempo- 
 Tnvestment. rarily sustain their accurate relation until they are 
 
 safely transferred to the investment. In this partic- 
 ular it is necessary that they should be so securely united as to prevent 
 any possible displacement during the process of removing from the model, 
 and the subsequent imbedding into the investment material, with a sub- 
 stance sufficiently tough and strong to withstand such procedure. 
 
 This is usually accomplished by using a hard or adhesive wax as a 
 medium of cementation, which in large cases may be further sup- 
 plemented by covering the facings and crowns from the buccal or labial 
 
39 
 
 surfaces with a thin layer of plaster or investment compound previous to 
 removing from the articulator. (Fig. 24.) 
 
 In interrupted bridges or where some adaptation of bars or rests to 
 a proper relation with the natural teeth is indicated, it may often be done 
 to better advantage after the case is invested than when on the model. In 
 such instances by extending or continuing the wax over these teeth so as 
 to secure an impression of them before detaching and investing, their ac- 
 curate reproduction may be secured in the investment. 
 
 For the purpose of thus securely cementing the 
 Uard lUax, parts a hard wax composed of from two to four 
 
 parts of resin and one of wax is reliable and much 
 used. The combination forms a stifif, brittle substance, which for con- 
 venience should be rolled out into sticks of suitable size and length. These 
 may be kept indefinitely by coating the surfaces with whiting or plaster 
 to keep them from adhering to each other. Parr's fluxed wax may also 
 be used for the purpose. 
 
 As the extreme brittleness of hard wax is some- 
 JldbCSiVC max. times objectionable, a less brittle and more adhesive 
 compound may often be found preferable. The fol- 
 lowing formula gives an adhesive wax possessing excellent qualities : 
 White bee's wax, 8 oz. ; pulverized white resin, 1^2 oz. ; gum dammar, 
 i^ oz. Melt in order named. 
 
 When the various parts are securely and firmly 
 Tltoesting. united, the wax should then be carried over a con- 
 
 siderable surface of the abutment crowns and caps, 
 including every portion of the work not to be subsequently covered by 
 investment material. This procedure serves to keep such surfaces clean 
 and free of dirt, and leaves them fully exposed in the investment, by guid- 
 ing the flowing of same over only those parts which should be protected. 
 
 In all cases, ranging from a single crown up to 
 $|na11 Cases. four or five teeth, the abutment crowns and caps 
 should be detached from the model, previous tc 
 cementing the parts, in such manner as to preserve their definite outline 
 and relation. Upon being again replaced in their proper position all of 
 the individual parts may be assembled and cemented together, when the 
 whole can then be easily removed and invested. This eliminates the de- 
 struction and investing of the model and preserves it for future use in 
 case of desire or necessity. 
 
 In larger cases, however, it is not usually good 
 €xtcn$iV( Cases, policy to follow this procedure, because of the in- 
 creased liability of an inaccurate replacement of the 
 abutment caps and crowns, especially if there be more than two. In such 
 instances it is always safest and best after assembling and cementing the 
 
40 
 
 parts firmly to first remove the model from the articulator, and then trim 
 away all surplus plaster until only enough remains to sustain the relation. 
 (Fig. 25.) This, then, precludes the possibility of any disarrangement 
 or displacement of the parts, and the remaining plaster is of no signifi- 
 cance if entirely submerged and completely covered with the invest- 
 ment material. 
 
 The investmicnt compound should be mixed of 
 
 Pf(C3UtiOn$. a moderately thin and plastic consistency, so that 
 
 when the proper quantity is poured upon a piece of 
 
 paper it will offer no resistance in pressing the case down into place, 
 
 until it is properly submerged and sufficiently covered. If too stiff there 
 
 would be danger of a change in the relation of the parts. 
 
 To make sure of a close adaptation of the material to the facings 
 and other parts, and to hold them securely when invested, all surplus 
 wax and dirt should be carefully removed and the case dipped in water 
 just previous to bringing it in contact with the investment material. 
 
 Fic].25. 
 
 The interior of all crowns and caps unless previously well -filled with 
 plaster should then be first thoroughly packed with the investment ma- 
 terial by using a small piece of wood or fine-pointed spatula; because if 
 not perfectly filled the presence of air spaces, into which the heat be- 
 comes concentrated during the process of soldering, will materially in- 
 crease the liability of burning or fusing the parts, an accident which for 
 this reason not infrequently occurs. 
 
 After the investment has become thoroughly 
 
 K^tnovind Ultax. hardened and the surplus trimmed away, the -wax 
 
 should be slightly warmed by passing over the flame 
 
 and removed as well as possible with a small knife-blade or other pointed 
 
 instrument, being careful not to loosen or dislodge the parts in so doing. 
 
 Hot water may be then poured upon it, but the case should never 
 be boiled, for the reason that such procedure disintegrates the com- 
 pound, interferes with its perfect crystallization, and requires more time 
 in drying out and heating up than would otherwise be necessary. 
 
 Choloroform, being a solvent of wax, is also used to remove remain- 
 ing particles, but this is -entirely unnecessary, because the wax will be ab- 
 sorbed by the investment and ultimately burned out entirely during the 
 heating process. 
 
41 
 
 As soon as the wax has been sufficiently re- 
 Prcparation moved, the investment should be trimmed down 
 
 Of Tnpesttwent. until no larger than is absolutely required, thus 
 leaving all surfaces upon which the solder is to be- 
 come attached freely exposed, so as to offer no impediment to the heat- 
 ing of the case. No danger will accrue from this free exposure of the 
 
 Fiq.26. 
 
 parts if the porcelain facings are covered and the interior of crowns and 
 caps well filled, and the labor involved in the process of soldering will 
 be materially lessened. 
 
 The investment tor a suigle crown sliould be cut away from the 
 approximal sides on a line with the backing and cap. (Fig. 26. j Where 
 this is not observed and the investment remains banked up on these sides, 
 
 Fia.27, 
 
 the crown is imbedded into a depression, and the soldering is made much 
 more difficult because the flame and heat from the blow-pipe is thus de- 
 flected from the parts. 
 
 This applies as well to more extensive work, and should always be 
 closely observed. The proper exposure of the metal parts and the neces- 
 sary trimming away of the investment for larger cases is illustrated in. 
 Fig. 27. 
 
 When the preparation has been completed and 
 Drying and locating, all particles of debris removed, the parts should then 
 be fluxed, and the case placed upon the burner until 
 it grarlually becomes sufficiently heated to proceed with the soldering. 
 
42 
 
 Many devices are provided for holding the case in the flame, but the 
 simplest, most useful and economical method is to put it upon a piece 
 of the ordinary metal lathing used in plastering, which is made of iron 
 and is more or less durable, and then place this upon the spider over the 
 flame. (Fig. 28.) 
 
 Several preparations possessing the required 
 Prepared Compounds, qualities to a greater or less extent can be easily pro- 
 cured, among which may be included Dr. R. C. 
 
 Ficj23. 
 
 Brophy's "Imperial Investment Material," the investment compound 
 made by the Consolidated Dental Manufacturing Company ; "Sump,'' 
 prepared by the S. S. White Dental Manufacturing Company, and 
 "Teague's Compound," all of which are of special merit and can be 
 highly recommended. 
 
 w Jj/ 
 
Requirements and 
 Cecbnique of €rown Construction. 
 
Indications and Requirements. 
 
 CHAPTER V. 
 
 Indications: Extensive Caries. Accidental Causes. Discoloration. Malformalion . 
 Malposition. Requirements : Physiological Relations. Anatomical Relations. 
 Stress. Articulation and Occlusion. Approximal Contact. Mechani- 
 cal Relations. Method of .Attachment. Dowels. Telescoping. 
 Fit. Strength. Esthetic Relations. 
 
 Before one is properly prepared to consider the manipulative proce- 
 dure incident to the detail of construction of artificial crowns, a clear 
 conception and a thorough understanding of :he indications for. and re- 
 quirements of such substitutes for the natural crowns of teeth as are 
 generally applicable today are essentially necessary. 
 
 It does not matter particularly in what line of art or mechanics one 
 confines his efforts, to meet with success in the direction chosen requires, 
 first of all, the necessit}' of formulating in the mind, or picturing in the 
 mental eye, the result of the contemplated effort in the finished state, 
 before even commencing the detail of its construction. 
 
 To thus conceive the possible result before the execution, in a work 
 where art and mechanics are so closely related to nature, greatly 
 enhances the possibilities by cultivating the possession of those lucid and 
 perceptive ideas which are so essential to success if success is dependent 
 upon the attainment of special skill, as it should be. 
 
 And yet while dentistry offers no greater opportunities for the ac- 
 quirement and display of the highest artistic talent than in the field of 
 crown-work, such prerequisites alone will not always insure success, but 
 must be supplemented by a degree of accuracy, facility and delicacy in 
 instrumentation which will at once inspire the confidence of the patient. 
 
 Thus will he be the better qualified to obtain results more accurately 
 restoring the normal functions and more closely approaching a reproduc- 
 tion of nature ; and to perform them for the most nervous, sensitive 
 patients with more gratifying success to all concerned. 
 
40 
 
 In this field, as in many others, those methods which are quickest 
 and best are not necessarily synonymous, and so it often becomes a matter 
 of judgment and discrimination as to the employment of the particular 
 method most applicable to the case at hand, in which the operator must be 
 governed only by the most scrupulous and conscientious efforts. 
 
 While there may frequently be several methods of procedure that, 
 at the first conclusion, seem apparently applicable, there is usually one in 
 particular which upon closer observation will best meet all of the 
 requirements. 
 
 TnaicatiOHS. 
 
 The employment of artificial crowns is indicated in extensive loss of 
 
 tooth structure from the ravages of caries, or accidental causes, and not 
 
 infrequently because of discoloration, malformation and malposition, as 
 
 a means of substitution for the correction and restoration of impaired 
 
 function, and relief from disfigurement. There should always be enough 
 
 tooth structure remaining, however, to insure sufficient anchorage. 
 
 By far tl:c most general indication is in those 
 
 ■ -^ , . „ , instances where the natural tooth structure has suf- 
 
 exJcnsiDc Carles. , , . . t,, i x .1 r • 
 
 lerea such irreparable loss from the process of caries 
 
 as to make restoration by filling, with any assiirance of permanency in 
 
 the operation, either inadvisable or impossible. 
 
 In those cases, however, where it seems a matter of conjecture as to 
 the advisability of filling or crowning, unless for esthetic reasons, the 
 preference should be given to filling, if such procedure may seem to offer 
 an}^ certainty of a reasonable degree of success and permanency. 
 
 In frequent instances the remaining walls of badly broken down 
 teeth may be protected and usefulness restored for many years by the 
 insertion of a post into the canal, and the building of a filling around it, 
 and such a course is often indicated for the reason that the crowning 
 operation may then be deferred and become a subsequent and possibly 
 remote necessity, which would perhaps add to the aggregate longevity 
 of the root. 
 
 Moreover, the presence of a well-adapted filling is no doubt more 
 conducive to the preservation of the normal condition of the surrounding 
 tissues, than the most skilfully adapted crown. 
 
 The loss of a portion or all of the natural tooth 
 
 JfCCidcntal Causes, crown in the anterior region, as the result of a fall or 
 
 blow, or from overstrained masticatory action upon 
 
 hard substances in the posterior region, is by no means uncommon, and 
 
 usually calls for immediate relief in their reproduction and restoration. 
 
Discoloration. 
 
 47 
 
 The presence of a l^adly discolored tooth in the 
 anterior j^art of the nnjuth, which persistently refuses 
 to succumb to repeated efforts at bleaching-, may 
 
 Fiq. 29. 
 
 often indicate an artificial substitute as the only means of cfifectually and 
 permanently remedying its C(jnspicuous and objectionable a])pearance. 
 
 In such conditions of faulty enamel formation 
 
 malformation. as the so-called "'peg'" laterals (Fig. 29) anfl the 
 
 pitted enamel structure, as is frequently found to 
 
 exist in the first permanent molars and the anterior teeth (Fig. 30), the 
 
 Fiq. 3 I. 
 
 application of an artificial crown may often be indicated as the best means 
 of restoring usefulness and affording relief from disfigurement. 
 
 There are frequent instances of simple irregu- 
 
 inalposition. larity of the anterior teeth, where the age of the 
 
 patient, together with the presen*^" of caries or other 
 
conditions may not seem to warrant their correction by the process of 
 regulating. Often the desired effect may be obtained by sacrificing the 
 natural crowns and substituting artificial ones as the most simple and artis- 
 tic means of correcting the deformity. (Fig. 31.) 
 
 Keduiremcnts. 
 
 The success of crown-work in the various phases of its application, 
 and the degree of permanence in the operation, combined with the esthetic 
 results obtained, depends upon a close observation of the requirements 
 from a physiological, anatomical, mechanical and esthetic standpoint. 
 
 When it has been determined that a crown is 
 PbysiOlOSical indicated or seems to be the most advisable proce- 
 
 Rcl4tion$. dure, it is first necessary to ascertain the condition of 
 
 vitality of the immediate and surrounding tissues. 
 If pathological conditions exist, every effort should be made to locate 
 and remove the cause, and the usual remedial or medicinal agencies should 
 be applied until the tooth or root assumes as healthy and normal a condi- 
 tion as possible before proceeding further with the operation. 
 
 This particularly includes the thorough disinfection of the remaining 
 tooth structure, and the removal of all that may prove irritating to the 
 peridental membrane. The precaution is necessary because the presence 
 of an artificial crown should not afford any more reason or opportunity 
 for the deleterious action of disease-producing agencies than when the 
 tooth was in a normal healthy condition ; indeed, it should even further 
 fortify it against attack. 
 
 In regard to anatomical relations we are gov- 
 Jlnatontical erned by the position of the root and the artificial 
 
 Kclations. crown supported by it in their relation to the adja- 
 
 cent and antagonizing teeth, which includes the con- 
 sideration of stress, occlusion and approximal contact. 
 
 The roots of teeth carrying crowns are sub- 
 $trc$$^ jected to the influence of stress in different direc- 
 
 tions, according to their location in the arch, which 
 fact demands that the construction and application of artificial crowns 
 should be made with a view of affording a degree of resistance sufficient 
 to secure the greatest integrity of both. 
 
 As the line of the greatest natural resistance is in the vertical direc- 
 tion, every provision should be made tending to prevent undue and un- 
 natural stress, which might ultimately cause displacement, trouble, or 
 possible loss of the root. 
 
 In the anterior teeth the general tendency of the stress imposed is to 
 
49 
 
 force them outward and forward, which may and sliould always be re- 
 lieved as much as possible by the proper preparation of the root, the 
 restoration of approximal contact, and the method employed for the 
 attachment of the crown. 
 
 In the bicuspids the stress is received in both vertical and lateral 
 directions, which demands a firm seating to accommodate the former and 
 a strong method of anchorage to overcome the latter. 
 
 The molars are least susceptible to displacement for the reason that 
 lateral stress is limited in proportion to the degree of the normal accuracy 
 of occlusion ; and as the greatest stress is in the direct or vertical line, 
 the essential requirement is a good firm seating, sup[)lemente(l by accurate 
 ■occlusion. 
 
 The degree of usefulness and longevity of the 
 
 Jlrticulation and artificial substitute depends greatly upon such forma- 
 
 OcclUSion. lion of the articulating surfaces, and in the posterior 
 
 region the arrangement of cusps and sulci in their 
 
 relation to the antagonizing teeth, as will restore their normal functions. 
 
 The arrangement should provide for correct position not only when the 
 
 teeth are in direct occlusion, but also in their articulation or the act of 
 
 bringing them into occlusion. 
 
 The evils of faulty and imperfect occlusion are often apparent, and 
 result frecjuently in marked manifestations of virulent peridental and 
 neurotic troubles. 
 
 The restoration of approximal contact is of the 
 HPtM'OXitnal Contact, greatest importance, and is made so because of the 
 necessity for protecting the tissues in the interproxi- 
 mal spaces from the serious results of irritation. 
 
 These tissues promptly rebel against the slightest irritating influences 
 to such extent as to demand the most stringent efforts toward tb.eir pro- 
 tection and preservation. 
 
 Due thought should be bestowed upon the 
 mechanical method of attachment, fit and strength of artificial 
 
 KslatiOi)$. crowns, all of which are so necessary and add so 
 
 materially to the durability and degree of perma- 
 nency in the work from a mechanical standpoint. 
 
 Two general methods of attachment are em- 
 IDctbOd of flttachmcnt. ployed, each or either of which may be indicated by 
 the style of crown required, and the amount of tooth 
 structure to which the attachment may be made. 
 
 In roots which are even with or approximating 
 
 Dowels. the gingival line, attachment must necessarily be made 
 
 by inserting a dowel in the direction of their longi- 
 
50 
 
 tiulinai axis to a depth, where possible, equal to the leno:th of the crown 
 from cervix to incisal or occlusal edge. 
 
 Such a mechanical fixation, whether the dowel be previously attached 
 to crown or root, practically precludes the loosening of the parts from 
 strain, at the line of junction, overcoming,' leverage at that point by 
 distributing it throughout the length of root, and forms a most secure 
 means of anchorage. 
 
 Where enough of the root is freely exposed to 
 
 tCkSCOpittS. afford a firm grasp of the crown, the attachment may 
 
 be securely made by telescoping, in which the 
 
 strength at the line of junction naturally increases in proportion to the 
 
 surface of tooth structure covered by the crown. 
 
 Tl:e relation existing between the crown and 
 iWdaptaJlOlt— Tit. root is of the greatest possible importance, because 
 the ratio of subsequent failure or trouble ari ing from 
 the progress of caries, or from gingival or peridental irritation, is de- 
 creased in proportion to the degree of accuracy in the adaptation. 
 
 The crown should be seated firmly upon the root, and if no band is 
 used the adaptation should be close enough to make a joint as flush and 
 impervious as possible, so that the end of the root may be thus pro- 
 tected. 
 
 When a band is used, it should pass under or within the free margin 
 of the gum a uniform distance on all surfaces of the tooth and only far 
 enough to cover and protect the seam of union, which should be in such 
 close proximity to the root as to preserve its continuity and make a smooth 
 line of junctiori between the two. 
 
 The durability of this work depends to a very 
 Strength. large extent upon its inherent strength, which it 
 
 should always possess to a degree sufficient to per- 
 manently withstand the stress of mastication, even though it be gained 
 at the sacrifice of more or less artistic results when occasion requires. 
 Any tendency toward undue economy usually proves disastrous. 
 
 These considerations embrace the field which 
 
 esthetic KelatlOlt*. gives the greatest possible scope to the individuality 
 
 and artistic temperament of the operator, and while 
 
 it is true that art can never entirely and completely take the place of 
 
 nature, the aphorism is less applicable to this special line of work, perhaps, 
 
 than to any other department of dentistry or of art. 
 
 To secure the highest artistic results, the artificial crown should pre- 
 serve the gingival outline, and the symmetrical alignment of the teeth ; 
 should be proportionate in length with the adjacent teeth, and if of porce- 
 lain should closely match them in color, and should correspond favorably 
 
in general form and characteristics with its fellow member (^f the opposite 
 side of the arch. 
 
 As a rule, where porcelain is used no metal should be exposed to 
 view from any surface, unless purposely done to more closelv match the 
 adjacent teeth or the corresponding tooth. 
 
 In instances where the remaining natural teeth are freely filled witli 
 gold, the artificial substitute should often carry fillings which will enable 
 it to more closely resemble and harmonize with them, thus making detec- 
 tion more improbable, which legitimate deception is a true evidence of 
 artistic endeavor. 
 
Cbe Preparation of Roots. 
 
 CHAPTER VI. 
 
 rreliminary Requirements: Therapeutics. Feasibility of Devitalization: Physio 
 logical Considerations; Mechanical Considerations. Treatment of Hypertrophy, 
 Free Exposure of the Root. Classification. Preparation for Shell or Tele- 
 scope Crown: Requirements; Restoration of Continuity; Diminution of 
 Coronal Proportions ; Paralleling Converging or Diverging Teeth ; Opera- 
 tive Procedure. Preparation for Shell or Telescope Crown with Porce- 
 lain Facing: Requirements. Preparation for Band and Dowel Crown; 
 Requirements; Operative Procedure; Excising Incisors and Cus- 
 pids; Excising Bicuspids and Molars; Removal of Enamel: Use 
 of Enamel Cleavers ; Peripheral Trimming ; Shaping Basal Sur- 
 face. Preparation for Dowel Crown without Band : Require- 
 ments; Operative Procedure; Inseparable Dowels; Separ- 
 able Dowels ; Protection of Unsupported Walls. 
 Preparation of Canals: Requirements; Operative 
 Procedure. Treatment of Perforated Roots. Treat- 
 ment of Fractured Roots : Posterior Teeth ; 
 Anterior Teeth, Prognosis. 
 
 Paramount among the obstacles in the pathway of success, perma- 
 nenc}^ and comfort in crown and bridge work is the perfunctory, unskilfut 
 and profoundly indifferent methods so often employed in the procedure 
 incident to the treatment and preparation of roots. 
 
 In the entire subject there is probably no one distinctive feature oi 
 such intrinsic importance as the practical, scientific and skilful prepara- 
 tion of the remaining crowns and roots of teeth, for the reception of arti- 
 ficial crowns. 
 
 While the proper and necessary operative procedure may be arduous, 
 and replete with attendmg difficulties, the physiological and mechanical 
 requirements are equally exacting, and demand the same degree of care, 
 precision and accurac}' that would be essential to the preparation of the 
 foundation for any superstructure designed as a permanent evidence of 
 skill and usefulness. 
 
 Alore particularly is this true in our efforts, because the field of labor 
 is confined to living sensitive tissues which are so responsive to unnatiu'al 
 conditions that any apparent negligence must sooner or later manifest 
 itself, not alone in evidences of failure, but also in the serious discomfit- 
 ures accompanying the various stages of irritation. 
 
53 
 
 These usually present in the nature of gingival inflammation, and 
 peridental and alveolar absorption, to which conditions may be attributed a 
 very large percentage of the troubles arising, and the absolute loss of many 
 teeth. The common and exciting cause of such prevalent and some- , 
 times discouraging results can invariably be traced to faulty and miperfect 
 adaptation of the artificial crown, which in turn reverts, primarily, to 
 inadequate and unskilful preparation of the rcjot supporting it. 
 
 As clinical experience proves most conckisively that comfort and 
 permanency depend upon a conservation or re])roduction of the natural 
 conditions, such liabilities decrease of course in proportion to the degree 
 of accuracy observed in the operative procedure. 
 
 And as a degree of accuracy may only be obtained by an apprecia- 
 tion of the significance and importance of the requirements, a broad com- 
 prehension of the underlying mechanical principles, and a thorough, con- 
 scientious execution of the details is necessary. 
 
 To facilitate this the consideration of the subject must necessarily be 
 in accordance with a more or less scientific and systematic arrangement, 
 in the order of the practical application of the principles and technique 
 involved. 
 
 Prelitninarv Requirements. 
 
 When it has been determined that an artificial crown is indicated, the 
 first essential features to be observed should always include a considera- 
 tion of those requirements constituting the preliminary operative proce- 
 dure incident to placing the roots in the most favorable condition possible 
 for the subsequent permanent attachment of the crown. 
 
 The very first detail is obviously that of the 
 
 CberapeutiCS. therapeutic treatment necessary in securing an 
 
 aseptic condition of the root, including pulp canals 
 and surrounding tissues. 
 
 This should invariably precede the removal or destruction of any of 
 the remaining walls, because of the facility which their retention affords 
 for the application of the rubber dam, which is essentially desirable and 
 advantageous in rendering the field immune from secretions while med- 
 icinal applications are being made. 
 
 After the removal of all disintegrated structure, the usual remedial 
 agencies indicated by the requirements and the existing conditions should 
 be consecutively applied, until thorongh asepsis of sufficient potency to 
 preclude any possibility of subsequent disease or disintegration is obtained. 
 
 When this has been successfully accomplished, the pulp canals 
 should be thoroughly filled throughout their entire length, irrespective 
 
54 
 
 of the style of crown indicated, and the root filHng then temporarily cov- 
 ered and protected with cement to exclude the deteriorating influences 
 of moisture during its hardening and crystallization. 
 
 Teasibilitv of Devitalization. 
 
 The problem of the feasibility of sacrificing the vitality of pulps ii. 
 teeth which are to be subsequently crowned is one of great importance, 
 and is a portion of the operative procedure incident to the preparation of 
 such teeth, which requires the most conscientious and conservative con- 
 sideration. 
 
 For many years no special thought was given to this feature, and 
 such teeth as seemed to indicate restoration by crowning were treated 
 much in the same manner as though fillings were to be inserted. 
 
 The frequency of subsequent troublesome manifestations, however, 
 including the ultimate death of pulps with t'.ic attending consequences 
 of such pathological conditions as virulent peridental inflammations and 
 alveolar abscesses, have since caused the subject to be more carefully con- 
 sidered, until it is now most generally conceded to be a safer precaution, 
 in a great majority of cases, to destroy such pulps as a prophylactic proce- 
 dure as v.ell as to facilitate the necessary mechanical preparation, when 
 the crown is to entirely cover the end of the root. 
 
 It is now a more or less generally acknowledged 
 
 PbysiOlOglcal belief of the most eminent authorities that the pulp 
 
 Considerations. j^ purely a formative organ, and that its physiological 
 function terminates with complete development of the tooth ; that it is 
 not necessary to its vitality, stability and longevity after maturity, pro- 
 viding that the pulp cavity is perfectly filled ; thus there seems to be no 
 good reason for its preservation, taking into account the modern aseptic 
 means of removing it and treating and filling the canals. 
 
 Especially is this true where a crown is indicated, because the abnormal 
 encasing of the tooth so as to practically isolate it must at least diminish 
 the external influences of secretions and temperature upon the nerve and 
 blood supply of the pulp ; and because usually such teeth have already 
 been subjected to the irritating and devastating influences of caries, each 
 of which seems but to invite and pave the way for ultimate destructive 
 processes. 
 
 Other deleterious influences may come from the irritating action of 
 the cements used in mounting, or from the effects of the shock, or over- 
 stimulation induced by the necessary mechanical preparation, either of 
 which may often prove important factors in rendering such teeth sus- 
 ceptible to a "slow but often complete and unnoticed destruction." 
 
55 
 
 All things considered, the prophylactic measure seems the conserv- 
 ative one, and as modern scientific root treatment offers no palpable ex- 
 cuse for subsequent pathological conditions, it seems that the orthodox 
 dogma of preservation is inapplicable to a great majority of cases, 
 where experience and judgment teach us the demand for a perhai)S more 
 "radical" but manifestly safer procedure. 
 
 The contraindication for such treatment would be in the mouths of 
 patients under sixteen years of age, where in all pro1)ability complete devel- 
 opment of the tooth had not yet been attained. In such instances, however, 
 it would be as unwise to j^ass the crown entirely beneath the gum as it 
 would be to destroy the vitality of the pulp, unless both w ere necessary. 
 And after fifty years of age the necessity for such treatment is often 
 g'reatly diminished because of the physiological phenomena of the gradual 
 atrophy of the pulp, and the formation of secondary dentine, which so 
 lessens the sensitiveness of the structure as to admit freely of the neces- 
 sary preparation, while reducing the probability of the ultimate occur- 
 rence of pathological conditions to a minimum. 
 
 Occasional exceptions may also be warranted in those cases of ab- 
 normal development, faulty enamel formation, extensive abrasion as a 
 result of attrition, and where the absence of adjacent and occluding teeth 
 makes necessary but little, if any, preparation, but such indications can 
 only be governed by experience and judgment. 
 
 Because these considerations apply more par- 
 
 mccbanical ticularly to the posterior teeth,' where the shell or 
 
 (Considerations. telescope crown is indicated, and where the removal 
 
 of a considerable portion of the remaining tooth 
 
 structure becomes an absolute requirement, the destruction, of the pulp is 
 
 usually imperative as a means of making possible and facilitating the 
 
 necessary preparation in the diminution of the cbronal proportions of the 
 
 natural crown. 
 
 ^^'hen the vitality is preserved, this procedure, always exacting, is 
 ordinarily so difficult that it must be either perfunctorily and negligently 
 performed, or else the patient must be made to tolerate an exceedingly 
 and often excruciatingly painful operation. 
 
 Frequent evidences of flagrant indifference and negligence are so 
 manifest as to prove conclusively that in a large majority of cases the vig- 
 orous efforts necessary to secure the best and most successful results may 
 only be obtained under the most favorable conditions. 
 
 Creatment of l)ypertropl)y. 
 
 In instances where an exuberant growth or hypertrophy of pulp or 
 gum tissue is present, or may have almost entirely covered the end of the 
 
56 
 
 root, some difficulty may be experienced in applying the dam and pur- 
 suing the necessar}^ course of treatment. 
 
 Both may be greatly facilitated, however, by the immediate excision 
 and removal of such tissue at the first sitting, and, if the continuity of the 
 root be destroyed by disintegration, or if its length will not admit of the 
 application of the clamp and rubber dam, a temporary restoration can be 
 easily effected by adjusting a band of German silver closely encircling 
 the circumference of the root, as soon as the suppression of the hemor- 
 rhage, by the use of styptics, will permit. 
 
 Such a band, if properly and carefully fitted to the neck of the root,, 
 and trimmed so as to have no sharp or irregular edges, and not to in- 
 terfere with the occlusion, will at once admit of the application of the dam 
 by adjusting the clamp over it, and may remain in place and be worn with 
 comfort until the necessary treatment and final filling of the canals has 
 been accomplished. 
 
 If filled flush to the edge with temporary stopping at the end of each 
 treatment, it further serves to hermetically seal the dressing within the 
 root, and to compress the tissues so as to afiford a free exposure of the 
 periphery. 
 
 Tree Exposure of tbe Root 
 
 During the process of treatment in all badly broken down roots some 
 means should alzvays be employed to compress the tissues in such manner 
 as to freely expose the end, which greatly facilitates the fitting of the 
 band, or the adjustment of the crown, and materially lessens the usual 
 discomfiture attending the operation. 
 
 When the use of a temporary band is not indicated, or seems unneces- 
 sary, the same advantages may be gained by packing temporary stopping 
 into and over the end of the root, and under the free margin of the gum. 
 
 If the root is too shallow to anchor it securely, it may be so retained 
 by packing tightly against the adjacent teeth, or held firmly by ligatures 
 attached to them, or by inserting a small sharp tack through it and into 
 the tooth structure. 
 
 In instances where the accumulation of gases demand some vent, a 
 perforation may be made through the stopping at a convenient point. 
 
 Care should also be exercised to prevent undue pressure, which, if 
 existing for an indefinite time, might possibly cause injury to peridental 
 membrane or surrounding tissues, as a result of protracted lack of cir- 
 culation. 
 
57 
 
 Classification. 
 
 The principles involved in the necessary preparation of roots are 
 governed, of course, by the particular style of crown indicated, and, while 
 crown work is divided into tzvo general classes, according to the method 
 of attachment employed, a variation in the essential details of their indi- 
 vidual construction requires that each class be subdivided, and that the 
 subject be considered in four general classes. 
 
 In order to meet the requirements occasioned by this variation, each 
 class will be considered separately, and are as follows : 
 
 Preparation for shell or tele- 
 scope crown. 
 
 Preparation for shell or telescope 
 crown with porcelain facing. 
 
 Preparation for band and dowel 
 crown. 
 
 Preparation for dowel crown 
 without band. 
 
 Preparation for Shell or telescope Crown. 
 
 The detail of procedure indicated by the require- 
 RCdUircmcntS. ments for a shell or telescope crown, because of be- 
 ing generally confined to the posterior teeth, is 
 usually the most difficult, and should be closely observed. 
 
 In those instances where the ravages of exten- 
 RCStOftltion Of sive decay have caused the destruction of the remain- 
 €ontinuity. ing walls of the natural crown, so as to carry the 
 
 cervical border at some point within or beyond the 
 free margin of the gum, some means of permanent restoration of the con- 
 tinuity of the root is usually advisable. 
 
 This prevents the possible fracturing of unsupported walls during 
 their preparation ; adds materially to the integrity of the root ; greatly 
 facilitates the fitting of the band, and overcomes the probability of sub- 
 sequent disintegration arising from an imperfect adaptation of the band 
 to the margins of deep cervical pockets. 
 
 Such restoration can usually be best accomplished with amalgam, the 
 use of which affords a better opportunity for securing a close adaptatior* 
 between it and the margins of the root, with the assurances of a greater 
 degree of permanency. 
 
 Where the edge of the band, however, can be fitted closely to the 
 root at all points around its entire circumference, with a reasonable de- 
 gree of certainty, and where the walls are weak, the use of cement for 
 this purpose is preferable, because of the additional support rendered by 
 its adhesive qualities, and because any further destruction of the tooth 
 
58 
 
 structure for the purpose of securing retention is unnecessary ; but when 
 tlie. extreine depth of the marginal edge (Fig. 32) makes a close adapta- 
 tion of the band either impossible or doubtful, amalgam should be used. 
 
 In using amalgam adequate retention must be secured in the pulp 
 cliamber, or root canals if necessary. A thin circular matrix of German 
 silver, g. 34-36, should then be adapted, and so shaped as to make the 
 restoration of suitable form to save further preparation. After adjusting 
 tlais, its inner surface should be coated with vaseline, oil, or any lubricat- 
 
 Fic^.32. 
 
 ing substance, to prevent adherence of the amalgam, and insure its easy 
 removal after crystallization. To admit of and facilitate this the amal- 
 gam should never extend as high as the edge of the band, and a subsequent 
 sitting is usually necessary. (Fig. 33.) 
 
 In roots where the entire crown has been destroyed, it is usually 
 necessary to rebuild and restore a portion of it, in order to better and 
 more securely sustain the artificial crown, by obtaining greater integrity 
 between it and the root at the line of junction. This may be easily ac- 
 
 complished by adjusting the matrix, and firmly inserting a screw-post 
 into the most accessible canal, additionally fortified with cement (Fig. 
 34), and then building up with amalgam to the desired length and shape. 
 
 The diminution of the natural crown, or its re- 
 Diminution of maining walls, in a manner favorable to the require- 
 
 i^OfOnal Proportions, ments, is frequently a very difficult procedure be- 
 cause of the usual inequality, in teeth of normal pro- 
 portions, between the diameters of the crown and the cervix. 
 
59 
 
 This requires and necessitates the removal of considerable tooth 
 structure in order that the circumference may be reduced at every point 
 qcclusally, and at the uniform expense of each surface, at least equal to 
 the exact dimensions at the cervix. 
 
 While it is, of course, desirable to leave as much as possible of the 
 riemaining coronal portions, it will be observed from the illustrations 
 ("Fig. 35) that approximately about one-sixteenth of the structure from 
 the axial walls, and the occlusal one-fourth must be removed. 
 
 Such a requirement is not a hypothesis, but a physical and mechan- 
 ical problem which must necessarily be closely observed, in order that it 
 may be made possible for the band to approximate a close adaptation to 
 the normally constricted neck ; and to admit of a reproduction of the 
 occlusal surface in the artificial crown possessing sufficient thickness to 
 withstand the influences of constant attrition. 
 
 To further increase the opportunities for securing a closer continuity 
 between crown and root, the remaining walls should not merely be parallel. 
 
 Fia.35. 
 
 but should be slightly inverted, so that the band may fit more closely as it 
 is pressed rootwise, and thus prevent its edge from being forced into the 
 gum tissue, instead of under or within the frise margin. 
 
 This requirement is indisputably essential when the crown is intended 
 to approach or pass beneath the gum, if comfort and perm.anency are to 
 
6o 
 
 be obtained from the operation, and is one of the strongest arguments in 
 favor of the devitalization of the pulp. 
 
 Owing to the general tendency of teeth to gravi- 
 
 Paralkling, tate or tip toward the unoccupied area in interrupted^ 
 
 Gonocrfllns or arches (Fig. 36), in their preparation for bridgework 
 
 DiOCrging C<etb. it is essential to observe that the surfaces of eachi 
 
 individual root presenting toward each other, are 
 
 made absolutely perpendicular, as illustrated in Fig. 37. 
 
 Such a condition will frequently be found, and no matter how per- 
 
 ^y. 
 
 36. 
 
 ^,37. 
 
 fectly each individual root should be prepared, the presentation of per- 
 pendicular lines is necessary to admit of the adjustment of the bridge^ 
 after completion. 
 
 Operative Procedure. 
 
 As this portion of the operation is particularly trying to the patient,, 
 as well as the operator, a good assortment of stones, disks and burs, kept 
 sharp, even-edged, and mounted true, is essential, and all unnecessary 
 grinding should invariably be avoided. 
 
 When any of the walls of the tooth remain or approximate their full 
 length, the first detail should be to undermine the enamel to the desired 
 point by cutting away the dentine with a sharp bur. Such walls may 
 then be easily broken down with the excising forceps, and much unneces- ■ 
 
6i 
 
 sary grinding thus avoided. The surface of the occlusal end should 
 be ground smooth with a thick-edge stone. The buccal and lingual walls 
 may be reduced with a thin-edge stone of suitable diameter, in which 
 it is essentially necessary to keep the revolving stone moving upward and 
 downward against the surface of the tooth, to prevent the formation of a 
 shoulder or ridge at any point, and to assure a uniform reduction. 
 
 After these walls have been adequately reduced, the trimming of the 
 approximal walls, usually the most difficult, is next in order. When they 
 
 Ficj.3 8. 
 
 remain high enough to afford considerable support to the enamel, grind- 
 ing must still be resorted to, as the cleavers will be found practically use- 
 less in detaching and removing it unless it is more or less disintegrated. 
 
 For such purposes a thin-edge stone or diamond disk of suitable 
 diameter may be used, by beginning . from the occlusal end, at a point 
 about one-sixteenth of an inch from the periphery, and cutting through 
 on a slight angle until the interproximal space is reached. 
 
 f/a.3 9. 
 
 A small cross-cut fissure bur inserted into the interproximal space at 
 right angles to the teeth, and brought occlusally with considerable pres- 
 sure against the root, may often serve as a valuable supplement to the 
 stone, or sometimes answer the purpose itself, if sufficient care be exer- 
 cised to prevent mutilating the adjacent teeth, which may often be pro- 
 tected with a band matrix. 
 
 When adjacent teeth are absent, the procedure is less difficult, and 
 may be accomplished with a blunt safe-edge stone, as illustrated in 
 
62 
 
 Fig. 38, or a stone possessing the shape of an inverted cone. The latter is 
 'very often found most useful in reducing the surfaces of molars. 
 
 If the remaining walls are short, and the enamel is somewhat disin- 
 tegrated, the cleavers may be found very useful. 
 
 When sufficient diminution of the structure has been secured, the 
 sharp corners should be nicely rounded with burs and sandpaper disks, 
 and the necessary preparation is then completed. 
 
 The degree of accuracy thus obtained will be denoted by the freedom 
 and facility with which the measurement wire may be detached from the 
 root after being twisted taut, and the buccal and occlusal aspects should 
 present, as indicated in Fig. 39. 
 
 Ficj. ao. 
 
 Preparations for Sbell or telescope Crown witb Porcelain Tacing. 
 
 While the same general principles apply to the 
 K((tUiremcnt$. necessary preparation for a shell or telescope crown 
 with porcelain facing, and the same detail of proce- 
 dure is indicated, a variation is required. 
 
 This variation comprises grinding down the buccal wall sufficiently 
 to accommodate the presence of the facing, as the area to be occupied by 
 it must, of course, be gained at the expense of the remaining root. 
 (Fig. 40.) 
 
 This should never be done, however, until after all other require- 
 ments, as before outlined, have been observed, and it may be done to 
 even better advantage after the band has been fitted. 
 
 Preparation for Band ana Dowel £rown. 
 
 The requirements of root preparation for 9. 
 
 K^dUiretiKlttS. band and dowel crown are similar in peripheral 
 
 features to the requirements for a shell or telescope 
 
63 
 
 crown, but differ in that all of the remaining natural crown must, of 
 course, be sacrificed to more nearly approximate the gum line. 
 
 This is necessary because the line of junction between crown and* 
 root is made at this point in order to accommodate the artistic and) 
 esthetic presence of a porcelain facing. 
 
 Operative Procedure. 
 
 In the operative procedure incident to removing the remaining por- 
 tions of the natural crown, as much of it as possible should be cut away 
 and broken down to a certain point, in order to avoid all unnecessary 
 grinding. 
 
 Fi 
 
 'T 
 
 Fia. 0-2. 
 
 In, the incisors and cuspids this. may be quickly 
 
 excising Tticiscrs and easily accomplished by first tindermining the 
 
 and Cuspids. remaining enamel with a bur, and then cutting 
 
 grooves through it at a point which, when the crown 
 
 is excised, will leave a projecting end of the root about one-sixteenth of 
 
 an inch beyond the gum line. (Fig. 41.) . 
 
 Care should be exercised in cutting the grooves entirely through the 
 enamel, so as to relieve or reduce the shock, .and. prevent a fracture rootr 
 wise. The beaks of the excising forceps may then be placed/in th,' 
 grooves, and the crown easily and safely removed. ... ;• 
 
 In removing the remaining portion of ,tl>e 
 Excising Bicuspids crowns of bicuspids and molars, the grooves and exr 
 and ItlOlars. cising forceps possess the same advantages. 
 
 In their use, however, any remaining continuity 
 between buccal and lingual walls must also be first attacked with a bur to 
 -destroy their integrity. (Fig. 42.) This, in conjunction v/ith grooves, 
 .will facilitate their excision without shock or danger of fracture. 
 
64 
 
 The remaining ledge of enamel upon this pro- 
 
 K^tnoval Of €namcK jecting end of the root, which has been purposely 
 
 retained, for the time, must then be removed in order 
 
 tOfbring the greatest diameter beneath the gum, where the line of junction 
 
 between band and root is to be made. This can be best accomplished by 
 
 the use of enamel cleavers designed for the purpose. 
 
 The use of enamel cleavers of any design may 
 4I$C Of CttantCl or may not be of a desired degree of effectiveness; 
 aUWitS, according to the manner in which they are manipu- 
 
 lated, and the easy and expeditious removal of 
 enamel depends entirely upon their proper manipulation. 
 
 The edge of the cutting blade of the instrument must be placed above 
 ihe enamel and held at the proper angle in its relation to the surface of 
 
 Ficj.43, 
 
 Flxj.Q-^. 
 
 the root; and a fulcrum must be established to facilitate the application 
 and exertion of the necessary force to secure the destruction of what is 
 usually a very dense attachment. 
 
 The adjacent teeth, when present, will serve as a means of estab- 
 lishing such a fulcrum ; and in their absence the same may often be se- 
 •cured by placing a smooth piece of soft wood or rubber, of sufficient 
 thickness, against the incisal or occlusal ends of remaining teeth, or the 
 :gums, against which the thumb may rest as a means of affording oppor- 
 tunity for securing purchase and leverage. 
 
 While various styles of instruments have been suggested for this 
 purpose, those designed by Dr. C. S. Case (Fig. 43) will be found admir- 
 ahly* adapted to upper anterior roots ; and those designed by Dr. A. G. 
 
65 
 
 Johnson (Fig. 44) are especially useful for posterior and lower roots, 
 though adapted for universal use. The manner of holding them in the 
 hand and securing purchase upon adjacent teeth is illustrated in Fig. 45. 
 
 After all enamel has been removed, the pe- 
 PCfiphCral Crlltimlllfl* riphcry of the root should be made smooth and to 
 present a perpendicular line, as indicated before and 
 after in Fig. 46. This can be easily accomplished with a small fissure 
 bur; or, a set of trimmers suggested by Dr. J. H. Prothero (Fig. 47), or 
 the "Root Reducer," manufactured by the S. S. White Co. (Fig. 48), 
 both of which are designed for this purpose, and may be found useful. 
 
 Fia. 0.6. 
 
 Before considering the final shaping of the end 
 Shaping Basal or basal surface of such roots, it may be well to em- 
 
 Surface. phasize that they have been purposely left projecting 
 
 somewhat beyond the gum, as indicated, until the 
 peripheral preparation is complete, because of thus materially facilitating 
 the removal of enamel, and the subsequent taking of the measurement and 
 fitting of the band, and for the reason that this freely exposed and project- 
 ing surplus end serves to retain the wire until an accurate measurement 
 may be secured, and to conform the hand to the proper shape and guide it 
 to place in fitting. 
 
 The fitting of the band is thus made practically free from discom- 
 fiture to the patient, and easy for the operator, and after it has been fitted 
 and trimmed to the desired width, the root should then be cut down to 
 the proper form of base. 
 
 The shape given the basal surface of the root is of much importance, 
 and particularly in the upper anterior teeth, where the requirements make 
 it desirable to leave the lingual edge somewhat longer than the labial in 
 
66 
 
 order to afford greater mechanical resistance to the stress naturally im- 
 ■ posed, and to carry the labial edge a trifle beneath the gum, so that the 
 band or cap may be invisible, and the neck of the porcelain facing placed 
 in close proximity to the gum line. 
 
 Compliance with these mechanical and esthetic requirements results. 
 of course, in beveHng the end of the root, as indicated in Fig. 49 (which 
 
 /ii fr^'Mi 
 
 // , 
 
 ^^^"f^Y^ 
 
 f/a.SO. 
 
 Ficj.Sf. 
 
 is the common practice), or in shaping it on a slight and gradual inclined 
 plane, as illustrated in Fig. 50. The latter is the best and preferable 
 ■preparation, because of affording greater opportunities for the adapta-* 
 tion of the cap and facing without causing undue prominence at the neck 
 (a common fault with artificial crowns), and with a minimum of grinding 
 of the facing, and a maximum of strength in the crown. 
 
 ,;'«Wl\i\l 
 
 ncj,5p. 
 
 This can be best accomplished with a flat-edge carborundum or 
 "vulcan" carborundum stone (Fig. 51), kept wet when using (the latter 
 having the advantage of wearing true) , until the gum line is reached, 
 when the Ottolengui root- facers (Fig. 52) are most useful in cutting it 
 beneath the gum on the labial or buccal edges, without lacerating Mie 
 tissues. These should be of the "safe-sided" variety, and are : made iin 
 
67 
 
 three sizes, to accommodate the size of root and the space between adja- 
 cent teeth, and should be used with extreme care, as they cut rapidly. 
 
 In the preparation of bicuspid and molar roots, where the stress is 
 direct, it is usually desirable to leave the basal surface almost fiat, as in- 
 dicated in Fig. 53. This allows more opportunity for securing strength 
 in the finished crown, and adds to the possibilities for its closer adapta- 
 tion and for an observance of the more artistic and esthetic requirements. 
 
 In no instance, however, should this final preparation be made 
 until the hand has been fitted. 
 
 Preparation for Dowel Crown without Band. 
 
 In the preparation of roots for the dowel crown without band, the 
 same procedure applies to the removal of the remaining natural crown, 
 as indicated in the preparation for this style of crown with a band. 
 
 After the remaining portions of the natural 
 R((SUircmcnt$. crown have been sacrificed, however, the essential 
 features differ somewhat in the shape given to the 
 basal surface, and in that the removal of enamel, or any peripheral prep- 
 aration, is, of course, entirely unnecessary. 
 
 Operative Procedure. 
 
 As the permanency and success of such crowns depend, to a great 
 extent, upon the degree of accuracy secured in the adaptation to the root, 
 its end must be so shaped as to render the opportunities for a close adapta- 
 tion most favorable. 
 
 In the preparation for that style of crown in 
 
 Tnseparable Dowels, which the dowel is an integral part (as the Logan 
 
 crown), the form given to the basal surface should 
 
 be exactly as indicated before, in Fig. 50, and the procedure is identical, 
 
 excepting the removal of enamel. 
 
 This preparation becomes necessary because the presence of an im- 
 movable dowel makes the grinding of the crown to adaptation with the 
 root somewhat difficult at best, but which is facilitated, of coiu'se, by hav- 
 ing the root present as smooth a surface as possible. The labial surface 
 may then be brought in contact with the gum margin, which is desirable 
 for esthetic reasons, while the line of junction upon the lingual surface 
 will be in accord with prophylactic measures in being rendered self- 
 cleansing by exposure to the secretions and movements of the tongue. ' 
 
68 
 
 The difficulty in adapting such crowns because 
 Separabk DCWdS. of the interference of the dowel in grinding, consti- 
 tutes the advantages possessed and afforded by those 
 with separate dowels, such as the Davis crown. 
 
 Where it is intended to construct the crown with 
 Plate and D0W(1« plate and dowel as separate parts, to be subsequently 
 attached with solder, and where the close adaptation 
 of the plate may be secured by swaging or burnishing, the lingual por- 
 tion should also be beveled almost to the gum line. (Fig. 54.) 
 
 By thus saddling the end of the root, greater mechanical resistance 
 
 is offered to the displacement of the crown, while the prophylactic require- 
 ments are secured in a better adaptation of the surface, and a closer ap- 
 proximation of the edge of the plate to the periphery of the root. 
 
 In roots which present a concave base as the re- 
 
 ProUCtlon Of suit of extensive decay, the walls should first be 
 Unsupported malls, ground down until smooth, and as dense as the mar- 
 ginal outlines noted will admit, and then supported 
 with a suitable material. 
 
 When the continuity remains unbroken, cement will best answer the 
 purpose, but if some restoration seems necessary, the use of amalgam is 
 usually indicated for the reasons mentioned. 
 
 As mechanical retention is frequently impossible, in these roots, 
 some difficulty may be experienced in anchoring it where its use is indi- 
 cated, but this may be accomplished by first thoroughly roughening or 
 serrating the dentine with a wheel-bur, and then flowing over it a thin 
 coating of cement and immediately packing the amalgam to place. 
 
 The cement thus aids materially in securely anchoring the amalgam, 
 and a more permanent restoration is often afforded. 
 
 In very extensive decay these walls may sometimes be better sup- 
 
69 
 
 ported by forming the base of the crown itself to closely fit them, so as to 
 offer the necessary protection when mounted with cement. 
 
 Preparation of €anal$. 
 
 The preparation of the canal for the reception of the dowel should 
 always be the last procedure, and is of special significance since the dowel 
 plays such an important part in the retention and stability of this style of 
 crown. 
 
 The necessary preparation consists in enlarging' 
 
 Ke(|Uireincnt$. them sufficiently to receive a dowel proportionate in 
 sise zvith the diameter and probable length of the 
 root, and consistent zvith the requirements of the crozcn. Any further 
 enlargement and destruction of tooth structure is injudicious and unneces- 
 sary. 
 
 One dowel is sufficient to support any crown, providing that it may 
 extend into the root a depth equal to the length of the crown (Fig. 55), 
 
 which is a mechanical requirement, and possess strength enough to with- 
 stand the stress. 
 
 In upper first bicuspid and in molar roots, however, if the probable 
 length or constriction of the root precludes this, two may be used. 
 
 After first so determining the size of dowel indi- 
 
 OpttMiVi Procedure, cated, or to be used, in the individual case, the canal 
 
 should then be enlarged to receive it. A twist drill 
 
 or sharp round bur approximating the same diameter as the dowel should 
 
 then be selected, and the canal reamed out to adequate proportions. 
 
 In most instances it is desirable to extend the opening into the canal 
 somewhat lingually. in order to permit the dowel to pass through the 
 cap at a point which will carry its projecting and surplus end out of the 
 way, so as not to interfere with the adjustment of the neck of the facing 
 to proper relation. 
 
 Considerable care should be exercised, especially in bicuspid and 
 
JO 
 
 constricted roots, to avoid drilling through the sides of the root, as such 
 perforations usually cause much trouble, and may often result in the loss 
 of the root. 
 
 For this reason the round bur is considered the best and safest means 
 of enlarging canals, because if of a proper size, and carefully guarded, 
 as it approaches the periphery an immediate response will be manifested 
 from its approaching proximity to the peridental membrane, in ample 
 time to cause cessation of drilling and prevent perforation of root. 
 
 Creatttient of Perforated Koots. 
 
 The presentation of perforations through the root, whether from 
 accidental causes or as the result of caries, is usually a most aggravating 
 state of affairs, and calls for much painstaking effort to again place such 
 a root in condition to remain permanently comfortable. 
 
 A hermetical and non-irritating seal is required, for which purpose 
 soft gold foil, tin foil, cement, white paraffin and gutta percha are 
 generally used. 
 
 While all possess some good qualities, the use of chemically pure tin 
 foil is most universally successful. 
 
 When these cases present, all septic and inflamed conditions of im- 
 mediate and surrounding tissues should first be relieved by the proper 
 medicinal applications. A small cone of chemically pure tin foil, about 
 No. 4 thickness, should then be rolled, and inserted into canal, until one 
 end is passed through the perforation. With a smooth, blunt, root canal 
 plugger, the remaining portion of the cone should be gently packed 
 against the walls over and surrounding the perforation, and then small 
 pellets of slightly moistened cotton should be packed into the canal to 
 burnish the tin to close adaptation. 
 
 Upon the removal of the cotton the tin may be protected and held in 
 place by covering with chloro-percha and filling the root with cement. 
 
 When such treatment becomes necessary before filling the canals, 
 their location may be preserved to admit of same by the insertion of a 
 broach into each, the subsequent removal of which will leave them still 
 accessible for further treatment and final filling, through the open- 
 ings thus made. 
 
 The use of tin is preferable to other materials, because it is easily 
 adapted, even in the presence of moisture, and is absolutely non-irritating, 
 and offers a still greater advantage in the hermetical sealing afforded by 
 the subsequent formation of the oxide, which chemical action is induced 
 by contact with the moisture of the tissues. 
 
Crcatmcnt of TractureJ Roots. 
 
 The not infrequent presentation of fractured roots, and the difficul- 
 ties usually encountered in their treatment, require a definite knowledge 
 of the various means employed to restore and preserve their usefulness, 
 and a delicacy and dexterity of manipulation in the procedure. 
 
 In the posterior teeth these conditions usually 
 Posterior Ccctb> result from overstrained or undue masticatory force 
 upon such teeth as may have been weakened by the 
 presence of extensive decay, or very large fillings, involving the approx- 
 imal and occlusal surfaces, and causing a longitudinal fracture of the re- 
 maining crown and root. 
 
 Such fractures usually extend from mesial to distal surfaces, separat- 
 ing the buccal from the lingual cusps, and may often be successfully 
 treated and permanent usefulness restored by crowning the root. 
 
 When such a course seems indicated, the first procedure should be the 
 
 Ficj. 56. 
 
 thorough removal of all loose particles, by freely washing and flooding the 
 tooth with tepid water, until a perfect and close approximation of the 
 parts may be secured. 
 
 This approximation should then be securely retained, temporarily, 
 until permanent fixation may be obtained by mechanical means. 
 This may be accomplished by using well annealed German silver, or or^ 
 dinary silver suture wire, from 23 to 26 g., which should be passed around 
 the circumference of the tooth at the neck, and the ends then twisted 
 tightly together. 
 
 The German silver wire is preferable because of admitting of greater 
 strain without breaking, and if therapeutic treatment is necessary it 
 may then proceed until the tooth and adjacent tissues are placed in favor- 
 able condition. 
 
 The mechanical procedure then necessary to firmly and permanently 
 anchor the parts is governed by the extent of structure possessed by each 
 independent portion. • 
 
72 
 
 If enough remains of each portion, they may be securely attached by 
 cutting dovetail grooves in each, and then flowing a thin layer of cement 
 over the entire interior surface, thus utilizing its adhesive properties, and 
 then filling with amalgam. (Fig. 56.) 
 
 When the latter has become thoroughly craystallized, the wire may 
 be removed, and the tooth carefully shaped for the reception of the crown. 
 When insufficient structure in one of the parts precludes this procedure, 
 the desired result may be accomplished by first wiring securely, and then 
 adjusting the rubber dam and completely filling the tooth with thin 
 cement. 
 
 If the presence of moisture is prevented, the adhesive properties of 
 the cement, in conjunction with the wire around the neck, will usually 
 retain the parts until the tooth has been shaped, if care be exercised. In 
 this particular, the stone should ahuays revolve toward the fracture in 
 order to prevent displacement. 
 
 Fiq. 51. 
 
 The wire may then be removed, and the crown fitted and mounted. 
 
 Such fractures in the anterior teeth usually oc- 
 
 flntcrlor CCCtb. cur as the result of a blow or other accident ; or from 
 
 the stress of mastication upon an artificial crown 
 
 offering no protection against such strain and perhaps mounted upon a 
 
 root already weakened by too ext^isive or injudicious enlarging of the 
 
 canal for the reception of the dowel. 
 
 When the fracture does not extend b€;yond the border of the alveolus 
 to any appreciable extent, it is usually best to remove the loose portion, 
 compress the tissues with gutta percha, and restore with amalgam. Or" 
 if the necessary retention is not possible, the base of the crown may be 
 closely adapted to the root, and the restoration made with the crown. 
 
 When the fracture extends beyond the alveolus, however, it is usually 
 desirable to secure fixation and retain the loosened portion, in order to 
 prevent the resorption following its loss. 
 
 This may be accomplished by cementing and wiring until sufficient 
 preparation can be made to admit of the adjustment of the crown. 
 
7Z 
 
 If each portion possesses sufficient structure, additional strength may 
 often be secured in their fixation by the use of an uitradoilal band. 
 
 Where the length and thickness of the fractured part may seem ta 
 indicate such a procedure, the parts should first be tightly wired, as sug- 
 gested, and then a circular groove trephined a consistent depth through 
 the thickest part of each, into which a band may be subsequently fitted 
 (Fjg- 57) ; by the use of a very simple outfit suggested by Dr. B. J. 
 Cigrand. When the band has been adjusted to the groove and ground 
 smooth with the basal surface of the root, a firm secure fixation of the 
 parts is insured, and the wire may then be removed and the crown ad- 
 justed. 
 
 While some little suppuration and trouble may 
 ProanoslS. be subsequently present as a result of reuniting frac- 
 
 tured roots, it should give no unnecessary appre- 
 hension because if properly treated, and absolute immobility has been 
 secured, it is usually of but temporary nature, and many roots so treated 
 seem permanendy restored to usefulness, indicating a very favorable 
 prognosis. 
 
€De Sbell or telescope grown. 
 
 CHAPTER VII. 
 
 Indications, Contraindications, Requirements : Telescoping Portion, Occlusal 
 End, Methods : Sectional Method, Procedure ; Measurement, Bands ; Width, 
 Length, Soldering, Fitting, Contouring, Occluding Bite, Impression. Articulators. 
 Processes for Cusp Formation, Carved Cusp and Special Die Methods. Procedure ; 
 Swaged Cusps, Mould, Dies, Swaging, Adjusting Cusps, Soldering Cusp, Finishing. 
 Solid Cast Cusps. Cusp Formation without Models. Use of Ash's Crown Swaging 
 Device. Die and Die-Plate Methods; Individual Dies, Die-Plates; Application, Ad- 
 justing With Models. Adjusting Without Models. Hollingsworth System ; Appli- 
 cation. Millett's System, Application. Lowry System ; Application. Baird System ; 
 Application. Seamless Method: Advantages. Disadvantages; Time, Strength, 
 Adaptation. Detail of Construction; Primary Band, Bite and Impression, Prepar- 
 ing Model, Casting Flasks, Dies, Forming Blanks, Swaging, Adapting and Re-en- 
 forcing. Reverse Process: Advantages, Disadvantages, Procedure; Original 
 Model, Mould, Swaging-Model, Blanks, Swaging, Methods, Scott's Method, Finish- 
 ing. Application to Separated Molar Roots ; Procedure, Bands, Cusps. Applica- 
 tion to Individual Roots. Cantilever Bridges. Application of Amalgam : With 
 Band, Without Band. Application to the Anterior Teeth : Indications, Procedure ; 
 Adaptation to the Mouth. Adaptation to Models. Carving and Swaging. Die- 
 plate Methods; Lowry and Millett Systems; Hollingsworth and Baird Systems. 
 Seamless Method : Reproductions. Dowels. Ready-made Forms. Removing and 
 Repairing; Crown Slitting Forceps. Preserving Continuity of Bands. Repairing. 
 
 Brief reference has already been made to the history and usefulness 
 of the gold shell or telescope crown, and to this style of crown as having 
 been one of the early achievements in the preservation of badly decayed 
 teeth or roots, and the restoration to their former functional activity. 
 
 Regardless of the progress and development of crown work in gen- 
 eral, however, and irrespective of the esthetic and hygienic advantages 
 of porcelain work, this style of crown is still, and probably always will be, 
 one of the very best means and methods of subserving the requirements. 
 Indeed, when their application is indicated, and when the adaptation and 
 construction, by whatever method chosen, is practically and skilfully 
 executed, no other one method of procedure seems to offer so great an 
 opportunity for the serviceable and permanent reproduction of the 
 normal condition. 
 
75 
 
 As a natural consequence, and because of the time-proven value of a 
 method affording such opportunities and possessing the possible quali- 
 ties of strength and indestructibility to so great an extent, many roots have 
 been permanently saved and made useful that would otherwise have beai 
 lost; bridge-work, both fixed and removable in character, has devel- 
 oped and become practical ; and yet the esthetic and artistic possibilities of 
 modern prosthesis have been most flagrantly abused by injudicious use, 
 and indiscriminate application. 
 
 If dentistry is to become universally acknowledged as a profession 
 embracing a field of dignified and scientific pursuit, and if dental pros- 
 thesis is ever to be accorded the recognition and distinction of an art, to 
 which the scope of its possibilities entitle it, the somewhat common prac- 
 tice of placing gold crowns on teeth, within the range of vision in the 
 mouth, violating all traditions of art, must be considered as degrading, 
 and should be most vigorously condemned. 
 
 No matter how skilfully the operation may be made, or how perfect 
 the result obtained, such evidences of artificial handiwork whenever prom- 
 inently conspicuous are an ofifense to art, culture and refinement. 
 
 As a result of the appreciation by the laity of more artistic endeavor, 
 and their education at the hands of those conscientious enough to exercise 
 their dtity, the request for such work is now so limited, and so few will 
 even tolerate them, that the pernicious practice is of necessity confined 
 mostly to either unscrupulous charlatans, or to those who wilfully cater to 
 a perverted taste and a barbaric vanity. 
 
 As many teeth requiring artificial crowns, how- 
 Tndications. ever, are beyond the range of vision, gold crowns 
 
 may often be used without objection, and to the best 
 possible advantage. 
 
 Their application is indicated, principally in restoring the roots of 
 molars, and occasionally of second bicuspids, but rarely anterior to them. - 
 
 In cases of close occlusion, where the cusps of the opposing teeth 
 when brought into direct occlusion afford but little, if any opportunity for 
 securing sufficient strength with any style of porcelain crown ; and on 
 roots so short, disintegrated and weakened as to require support and resto- 
 ration with amalgam, especially in the mouths of men where their pres- 
 ence may not be conspicuous because of the beard, their application to the 
 first bicuspids may be sometimes permissible; also in the preparation of 
 bicuspids which are to serve as abutments for bridgework, where it seems 
 advisable to allow the natural crown to remain as long as possible, in 
 order to afford greater integrity in the attachment of the artificial crown, 
 and thus secure increased mechanical resistance to the stress imposed 
 upon the bridge. 
 
76 
 
 - - Anterior to the molars, however, and particu- 
 
 Contraindications. larly in the mouths of women, their appHcation is 
 usually contraindicated in view of the more artistic 
 means available. Any exceptions should be based only upon a conscien- 
 tious consideration of the existing conditions and practical requirements 
 of the case ; and their application to the incisors and cuspids, in any event, 
 should be regarded as an unpardonable offense. 
 
 KeQUirentetits. 
 
 The requirements for this style of crown do not dift'er essentially 
 from those of crown work in general, as previously outlined. Whenever 
 and wherever employed, they should be constructed of a material thick 
 and heavy enough to possess adequate strength when finished, and suffi- 
 ciently high in karat to withstand the chemical action of the secretions. 
 
 The band or that portion which telescopes the 
 tClC$CCping Portion, end of the root should fit closely around the entire 
 circumference ; pass a short, but tmiform, distance 
 beneath the gingival border of the gum, and possess a smooth rounding 
 edge so as to offer no possible irritating influence to the tissues surround- 
 ing it. It should also be contoured to typical form, restore the points of 
 contact, and preserve a proportionate and symmetrical alignment, with 
 the adjacent teeth. 
 
 The cusps forming the occlusal end should 
 j^ Occlusal €nd. mimic or approach a typical reproduction of the indi- 
 vidual tooth ; restore the normal occlusion by contact 
 with opposing teeth at several points, and offer no interference to the lat- 
 eral motion of the jaw in the various movements of articulation. 
 
 They should also be deep and sharp enough to aid in the act of mas- 
 tication, and of sufficient thickness to withstand constant and continued 
 attrition. 
 
 A very common fault with a large majority of these crowns is the- 
 presentation of a more or less smooth and uninterrupted masticating sur- 
 face. Such a condition precludes the proper mastication of food, and 
 minimizes the possibilities of service and usefulness, which may be easily, 
 obtained, and which qualities such substitutes for the natural condition 
 should always possess. 
 
 methoas. 
 
 The general usefulness of this style of crown has resulted in the 
 presentation from time to time of an innumerable variety of methods and 
 systems for their construction. - 
 
 The degree of skill possessed by, and the personal preference of oper-- 
 
77 
 
 ators enter into the use of all of them to such an extent as to have so far 
 prevented the adoption of any particular one as a universal system. 
 
 Two general methods of construction are employed — the Sectional 
 and the Seamless, and each has many diversified processes. 
 
 The sectional method, wherein the band and 
 Sectional method, cusp are made separately and subsequently united, is 
 the most commonly used. This procedure seems to 
 afiford more absolute accuracy in securing adaptation ; even better oppor- 
 tunities for the reproduction of the necessary contour ; consumes less time, 
 and admits of the use of a heavier gauge of gold throughout the construc- 
 tion of the crown. These important advantages cause it to be readily 
 accepted as the most universally successful method. 
 
 The joint made in the union of band and cusp offers no objectionable 
 features, and in no way interferes with artistic possibilities, if the edges 
 
 FJq.68. 
 
 of each are closely and perfectly approximated, and the union made with 
 a solder closely resembling the gold in color, and sufficiently high in karat 
 to withstand the chemical action of the secretions without subsequent 
 discoloration. 
 
 In the procedure incident to the mechanical con- 
 
 Proccdurc. struction of a crown possessing a band by any 
 
 method, the first detail is obviously that of securing a 
 
 true measurement of the diameter of the root to serve as a positive guide 
 
 in obtaining a band of accurate dimensions. 
 
 For this purpose wire, thin, narrow copper 
 measurement. strips, and waxed floss are used. Bessemer steel 
 wire, about No. 32, is preferable, however, because of 
 being easier to adjust and handle, and more reliable. 
 
. 78 
 
 It should be cut in suitable length, made in circular form, some- 
 what larger than the root, and the ends then securely attached in a small 
 Centimeter, avoiding any unnecessary surplus. 
 
 While many varieties of dentimeters have been suggested, a small 
 jeweler's slide pin-vise affords the quickest, easiest and most secure ad- 
 justment, with less danger of cutting the wire when twisting. 
 
 The loop of wire should be then placed over the root, passed just 
 freely beneath the gingival border of the gum, and twisted taut, being 
 careful in the meantime to conform and adapt it to all concavities of the 
 root. Fig. 58. 
 
 In very short roots, it may become necessary to hold it under the 
 gum with a suitable instrument, to prevent displacement while twisting; 
 and, while it is usually most convenient to have the twist upon the buccal 
 
 Fiq,60, 
 
 or labial surfaces, in second and third molars it may sometimes be found 
 more convenient to twist from the lingual surface. 
 
 After securing the correct measurement of the diameter of the root 
 the wire should be cut in two at a point farthest away from the twisted 
 portions, and each end of the former loop then carefully straightened out 
 until smooth, continuous with one another, and at right angles with the 
 dentimeter. Fig. 59. 
 
 When two or more crowns are being constructed for the same mouth 
 at the same time, especially when the roots are nearly of a size, each 
 measurement should possess some characteristic to distinguish it from the 
 other, by which means any confusion in the subsequent fitting of the 
 band may be avoided. This may be easily accomplished by so bending or 
 shaping the surplus ends as to differentiate between them, and have each 
 designate the root which it represents. 
 
79 
 
 Bands. 
 
 As the strength possessed by the crown, in its 
 attachment to the root, increases in proportion to the 
 thickness of the gold of which the band is made, so 
 long as it is not too heavy to be easily manipulated and accurately adapted, 
 and as gold stretches easily, and its thickness is necessarily diminished by 
 the subsequent process of finishing and polishing, 28 gauge (B. & S.) 
 plate, about 22 karat in fineness, should be used for bands. A gold for 
 this purpose is especially prepared by the Consolidated Dental Alfg. Co. 
 which is alloyed slightly with platinum, and possesses the advantages of 
 strength and toughness as well as being non-oxidizable, by which name it 
 is designated. 
 
 The desired width of the band should be noted 
 with the eye, or, if necessary, measured with a piece 
 of cardboard trimmed to the correct width, or with a 
 small compass. Fig. 60. 
 
 In cutting the gold the cervical edge, or that 
 which is to be fitted to the root, should be the exact 
 length of the measurement ware ; but the variation or 
 
 mm. 
 
 Eengtl). 
 
 Ficj.BL 
 
 Flq. 62. 
 
 inequality between the diameter of the root, in proportion to the dimen- 
 sions of the space to be filled by the crown, to obtain the most artistic re- 
 sults, often requires that one end of the band be cut on such an angle as to 
 make a difiference between the circumference of its cervical and occlusal 
 edges when soldered. Fig. 61. 
 
 While perfectly straight edges will often afford sufficient opportunity 
 for the necessary shaping and contouring of the occlusal end, it is fre- 
 quently desirable and sometimes necessary to have this edge of slightly 
 larger proportions, especially in bicuspids, in order to more perfectly and 
 artistically meet the requirements of contact and alignment. 
 
 Where the root is proportionately larger than the space to be filled, 
 however, the converse of the proposition may be indicated, in order to 
 secure and preserve an alignment of the occlusal surfaces. In such in- 
 
8o 
 
 stances the edges should be cut straight, in order to facilitate the adapta- 
 tion to the root, after which the circumference of the occlusal edge may 
 be adequately reduced. 
 
 When the band has been properly cut it should 
 SOldcrinS* be annealed, the edges filed smooth, so as to approxi- 
 
 mate evenly when brought into contact, and then 
 -given circular form. Perfect contact of the edges is essential to insure fit 
 and facilitate soldering, and may be sustained by first overlapping and 
 then bringing them back into direct contact. (Fig. 62.) This procedure 
 condenses the molecules sufficiently to overcome the expansion, when 
 Jieated, that would otherwise cause a separation, and is preferable to wir- 
 
 ing the outside circumference of the band 
 because the solder not infrequently pene- 
 trates the joint and attaches the wire to the 
 gold, which necessitates its being ground 
 off afterwards. 
 
 When the edges have been thus approxi- 
 mated, the band should be grasped with 
 fine-pointed pliers at a point as remote 
 from the joint as possible, so that they may 
 absorb but little heat. (Fig. 63.) Flux 
 should be applied, carried to the flame and 
 fused, and a very small piece of solder then 
 fluxed and placed immediately over the 
 joint. 
 
 In soldering, it should be held in the 
 flame so that each edge will be uniformly 
 heated, because if either should receive a preponderance of heat 
 the solder would become attached to it, and the addition of a second 
 rp'iece may be necessary. Any more solder than is required to make the 
 joint is objectional because of the additional stift'ness imparted to the 
 band. 
 
 As it is desirable to begin with a high grade of solder to prevent sub- 
 sequent re-fusing, and to admit of finishing with as high a karat as pos- 
 sible, all bands should usually be united with 22 karat solder, though 
 20 karat will answer the purpose. 
 
 .63 
 
8] 
 
 For convenience and comfort, the pliers used to hold the work in the 
 flame should possess a long handle and thin tapering points. (Fig. 64.) 
 The addition of platinum points, which may be easily attached with any 
 hard solder, increases their usefulness, as such pliers absorb less heat, 
 retain their shape more permanently, and offer more re- 
 sistance to the attachment of solder. 
 
 The fitting of the band may be 
 Titting. made accurate, easy and devoid of dis- 
 
 comfiture, in proportion to the relation 
 it bears to the shape of the root and to the outline of its sur- 
 rounding tissue, before any attempt is made to adjust it. 
 The detail of requirements in this connection apply to any 
 style of crown with a band, and are. 
 
 First — To conform the band to the general shape and 
 outline of the root. 
 
 Second — To trim the edge which is to pass beneath the 
 tissue to closely follozv the cervical curvature of the process, 
 and gingival festoon of the gum, so that it will come in con- 
 tact ez'enly and uniformly at all points, before the final 
 necessary pressure is applied. 
 
 Third — To round and smooth the edge so that no irri- 
 tating influence will be offered in forcing it beneath the gum. 
 
 I'ourth — For the purpose of convenience and of avoid- 
 ing any confusion in adjusting and readjusting; because the 
 usual convexity of roots at this point facilitates the adapta- 
 tion of the stiffened portion of the band, and because of 
 placing the soldered joint where it will be least conspicuous 
 in case of subsequent discoloration, as well as being most 
 easily accessible for reinforcement in the assemblage of 
 bridgework, the joint in the band should al-jcays be placed 
 at the center of the lingual surface of the root. 
 
 A neglect of any of these most essential features adds 
 materially to the difficulties experienced in, and the possible 
 discomfitures resultant frorn, the operation. In observing 
 them the band should be gently placed over the projecting 
 end of the root, and shaped with pliers until it is made to 
 conform to its general outline, and any existing concavities 
 or inequalities. Its surfaces should be made perpendicular, 
 and the edge then carefully trimmed with curved pointed 
 shears until it meets the gum line evenly at all points ; and 
 then nicely rounded from the outer surface with a fine half- 
 round file, until blunt but smooth. This minimizes the pos- 
 
 Efg.e4- 
 
82 
 
 sibilities of irritation, without obtaining any apreciable thinness of 
 the gold which would be objectionable because of increasing the 
 liabilities of stretching and irritation. 
 
 When these requirements have been complied with, the band should 
 be placed upon the root, and gently pressed to place until the edge passes 
 just freely beneath the tissue. For this purpose a small piece of wood of 
 convenient size, with f^at, smooth surfaces, is most useful ; and if properly 
 used greatly facilitates the operation, and obviates the driving of a band 
 into place, which is entirely unnecessary, and even brutal. 
 
 In instances where a recession of the gingival border of the gum may 
 have exposed the root beyond the normal outline at some point, such as h 
 not infrequently found to present in the mesio-buccal and lingual roots of 
 upper molars, an extension to the band may be indicated in preference to 
 sacrificing it upon other surfaces sufficiently to admit of thus approaching 
 the gum at this point. This may be best accomplished by first fitting the 
 
 band accurately without regard to this extension, after which a small 
 piece of pure gold plate may be soldered to the outer surface of the band, 
 and then trimmed until this denuded portion of the root is covered. When 
 the necessary burnishing has been completed, the adaptation may be sus- 
 tained by re-enforcing the extension with a high grade of solder. 
 
 When the cervical adaptation has been completed, the occlusal edge 
 should be trimmed to afford accommodation for the adjustment of a cusp 
 of uniform and sufficient depth, and then filed smooth and contoured. 
 
 The entire artistic effect of the finished crown, 
 
 0ontourin9« as well as the prerequisites of contact and alignment, 
 
 depends in a great measure upon the form and shape 
 given to the occlusal end of the band, which can be best observed at this 
 time. 
 
 By contouring is meant the reproduction of the natural form and 
 outline of the tooth, and while this may be accomplished with solder. 
 
83 
 
 after the cusps have been united, much time, energy and m.aterial can be 
 saved, and far more artistic results obtained, by properly shaping the 
 band itself. 
 
 Artistic results in this connection, however, arc made possiljle only 
 by a thorough knowledge of the angles, characteristics and general forms 
 of the natural teeth, the outlines of which should be reproduced in this 
 edge of the band. This may be done irrespective of the necessary shape of 
 the cervical edge in its adaptation to the root, and without change of it. 
 
 Fiq,6G. 
 
 For contouring purposes various styles and designs of pliers are 
 used, but as the shaping should be done upon the edge of the band, before 
 the cusp is attached, all of the necessary and artistic results may be easily 
 accomplished with pliers, the beaks of which are straight, tapering, and 
 come closely together, with rounded edges. A design of the author's for 
 this purpose and for universal use in crown work is illustrated in Fig. 65, 
 and, while some of the numerous other designs may be found occasionally 
 useful, these will meet the general requirements, when properly used. 
 
84 
 
 The rounded edges and one smooth beak prevent defacing the gold, while 
 the flat surfaces and one serrated beak, and the tapering form for stretch- 
 ing, adds to their general usefulness. 
 
 The average and typical requirements, and the results possible from 
 a knowledge of the form and outline of the teeth, and a skilful manipula- 
 tion of the pliers, are indicated before and after contouring the band in 
 Fig. 66. 
 
 In instances where the diameter of the root after its preparation is 
 larger than the proportionate dimensions of the occlusal surface, to se- 
 cure a symmetrical alignment with the adjacent teeth it may become 
 necessary to reduce the circumference of the occlusal edge of the band. 
 This may be quite easily accomplished by cutting numerous slits around 
 the approximal and lingual surfaces of the occlusal edge, and then draw- 
 ing the points in and overlapping them until the circumference is suffi- 
 ciently reduced. (Fig. 67.) These places may be afterwards filled in 
 
 nq.67. 
 
 with solder until a smooth uninterrupted surface presents. Although the 
 pliers previously mentioned may be used successfully, a very convenient 
 form especially adapted to this purpose, and generally useful in reducing 
 the size of either end of the band, when occasion requires, is illustrated 
 in Fig. 68. 
 
 After securing the proper and desired contour, this edge should be 
 filed smooth and even, the band then finally adjusted to the root, and 
 the occluding bite and impression taken. 
 
 The interior of the band should be filled even 
 
 OcciUditlS Bite. with the edge with wax previous to taking the 
 occluding bite. This facilitates the removal of the 
 latter from the mouth and its final adjustment to the model. 
 
 The occluding bite should always be taken separately from the im- 
 pression, and should precede it, because the imprint of the band is neces- 
 sary to admit of its adjustment to the model with the band in place. Wax 
 
85 
 
 is preferable for this purpose, because of the ease with which the relation 
 and a good imprint of the teeth may be secured, and of its more easy and 
 accurate adjustment to the model. 
 
 In obtaining it enough wax should be used to secure the imprint of at 
 least two teeth on each side of the crown, whenever possible, and in the 
 procedure it should be definitely ascertained that the teeth are in direct 
 and proper occlusion. 
 
 The patient should then be instructed to firmly close the jaw, 
 and press the wax against the lingual surfaces of the teeth with the 
 tongue, when by compressing it closely to the buccal surfaces with the 
 fingers a correct and well-defined bite is readily obtained. 
 
 The impression should alzi'ays be taken with 
 
 Impression. plaster, and, corresponding with the bite, should in- 
 
 clude two or more adjacent teeth, when present, on 
 each side of the crown. This is necessary in order to prove and govern 
 
 7. €8. 
 
 the occlusion when mounted upon the articulator. The use of plaster is- 
 essential^ for this purpose, because of the difficulty of, and uncertainty in, 
 readjusting the band to its accurate position in the impression, when any 
 m.aterial is used which draws perceptibly in removing from the mouth.. 
 This may be done with a degree of absolute certainty when plaster 
 is used. 
 
 Partial impression trays of convenient size for this purpose are iMus- 
 trated in Fig. 69, two being adapted for the right an^ left sides, and 
 one for universal use ; the latter, of course, is the most generally' use- 
 ful. Because of the natural shape of the teeth, it will usuallv be found 
 necessary to break the impression in removing it from the mouth, which 
 is not objectionable if the parts are afterward accurately replaced. A 
 
convenient tray, recently designed by Dr. E. L. Townsend to facilitate 
 such- procedure, includes a separable base composed of two smaller trays 
 with the dividing line in the center. Upon the removal of the outer tray 
 these remain in place, when they may be easily divided by the insertion of 
 
 the blade of a small penknife, which separates the impression in two lateral 
 halves. (Fig. 70. ) 
 
 When the parts are accurately readjusted and their relation securely 
 sustained with melted wax, the impression should be then varnished, filled, 
 separated, the bite adjusted, and then mounted securely upon the ar- 
 ticulator. For the purpose of facilitating the separation of the modc-1 
 
87 
 
 from the impression, the latter 
 should be first coated with a thin 
 solution of shellac in alcohol, and 
 followed, after drying, with a coat- 
 ing of very thin sandarac, in alco- 
 hol. The former causes a line of 
 demarcation of inestimable value in 
 separating, and the latter gives a 
 smooth, hard surface to the model. 
 Because of 
 Jlrtkulators. the desirability 
 of obtaining a 
 degree of accuracy in articulation 
 as well as occlusion, a reproduction 
 of the lateral movements of the jaw, 
 such as are made possible by the use 
 of an anatomical articulator, is al- 
 most as essential in crown work 
 as it is in the construction of ar- 
 tificial dentures. 
 For single crowns, however, such requirements, while always desir- 
 able are not so essentially necessary, and in the absence of a design more 
 con;eniently adequate for the purpose, the ordinary crown articula- 
 tor may answer. (Fig. 71.) 
 
 r/q. 70. 
 
 Fij. 71. 
 
 Procmcs for €ttsp Tormation. 
 
 Of the various methods and systems for securing suitable cusp forms 
 that will typify the natural teeth, and meet the requirements of articula- 
 
tion and occlusion, but one general line of procedure offers absolute 
 certainty and accuracy in all cases. 
 
 The importance of true occlusion, as has been previously empha- 
 sized, will be readily apparent, and is generally conceded, and yet through- 
 out the entire evolution of methods for procuring it, a system of stereo- 
 typed typical dies has predominated. As the conditions presenting vary 
 in proportion to the degree of the normal accuracy of occlusion, position 
 of the root, and its relation to adjacent teeth, and the length and shape of 
 band and depth of cusp required, the fallacy of expecting a ready-made 
 form to closely fit and approximate the edge of a properly contoured 
 band, and then articulate and occlude accurately with the opposing teeth, 
 is manifest. 
 
 Carved Cusp and Special Die methods. 
 
 If these mechanical and artistic requirements are to be observed, the 
 prerequisites of certainty and accuracy can be best obtained by forming 
 
 the cusp directly from an imprint of the opposing teeth, and in its proper 
 relation to the band, as was originally suggested in primitive form by Dr. 
 Norman W. Kingsley. While the detail of such a procedure may probably 
 consume a little more time than some methods, time is not the only factor 
 to be considered, except perhaps by dental laboratories; and the results 
 will usually justify such an expenditure. 
 
 When the models have been securely mounted 
 Procedure upon the articulator (Fig. 72), all surfaces of the 
 
 plaster in close proximity to the band should be var- 
 nished with a thin coating of collodion, sandarac or silex. The band 
 
89 
 
 rihould now be filled with thin, well mixed plaster, into which the occusal 
 surfaces of the opposing teeth are then imprinted by firmly closing the 
 articulator. (Fig. y2>-) The reproduction of adjacent teeth in the model 
 serves to sustain and prove the proper occlusion. When this has become 
 sufficiently crystallized, the articulator should be opened, and the band, 
 with its plaster contents, detached from the model in such manner as to 
 preserve its definite outline and relation. The surplus plaster around the 
 
 F/<f. 73. 
 
 outer edge of the band should be removed with the sharp blade of a 
 small penknife, which leaves the remaining contents somewhat crude and 
 inartistic in outline, but accurate in occlusion. (Fig. 74.) An artistic 
 effect, in proportion to the degree of skill possessed by the operator, may 
 be obtained, by inserting the grooves and pits of the typical outline 
 
 ^y. 74. 
 
 Fiq. 75. 
 
 of the tooth, which may be done without perceptible change to the occlu- 
 sion. In fact, the latter is thus improved because of the formation and 
 separation of the cusps. (Fig. 75.) 
 
 While modeling compound, mouldine and wax are sometimes em- 
 ployed for the formation of cusps, the use of any of them is not so reliable 
 as plaster, because of the tendency to flake in carving, or of the suscer^ti- 
 bility to change form in the subsequent process of securing the mould for 
 
90 
 
 the die, or for casting. In the process of carving, it is not ahogether 
 necessary that the correct anatomical outhne of the tooth should be repro- 
 duced, but only to typify it sufficiently to designate the tooth it represents. 
 This may be easily accomplished by inserting the grooves deep enough to 
 separate the cusps, and typical enough in outline to distinguish the right 
 from the left, and the upper from the lozvcr. (Fig. 76.) 
 
 In the reproduction of the plaster cusp in gold, two methods of pro- 
 cedure are employed, by means of which plate gold may be conformed by 
 swaging between dies, or a solid cusp produced by casting. 
 
 Because of the possibilities for securing a more 
 
 Swaged €USPS. distinct and definite reproduction of the outline; of 
 
 the time saved in adjusting and adapting the cusp to 
 
 the band, and of securing adequate thickness of cusp by subsequent re- 
 
 III! j| ipkii 
 
 RIGHT LEFT rvlCHT 
 
 F/a.76. 
 
 LEFT 
 
 7 
 
 enforcement with solder, the swaged method is usually preferable. 
 For this procedure the plaster cusp should be trimmed away uniformly 
 around its peripheral border, until the edge of the band is exposed. This 
 reduction in size allows for the thickness of gold forming the cusp, and 
 renders possible a perfect approximation of the edges of cusp and band. 
 If not observed, the cusp will be as much larger than the band as its 
 thickness, which will require the use of solder in securing a smooth sur- 
 face in its subsequent attachment. 
 
 A moulding ring (Fig. yy) should be filled 
 mould. even and flush to its edges with mouldine, into the 
 
 center of one surface of which the plaster cusp, after 
 being dusted with lycopodium or soapstone, should be firmly imprinteJ 
 just deep enough to secure the outline of the exposed edge of the band. 
 The mouldine should be packed closely against the band around its 
 circumference, and the band and plaster cusp removed from the 
 
mould. This should be dusted with lycopodium and the dies secured. 
 
 The most useful and coixvenient system of dies 
 
 Dk$. may be secured by placing a casting cup (Fig. 78), 
 
 which has a small perforation through the center of 
 
 the base, over the mould, and casting a cusp-button of pure tin or Watt's 
 
 metal (Fig. 79). After cooling, the button should be detached from the 
 
 cup with a small knife-blade, and placed upon a smooth surface of mould- 
 
 /"/c?.77. 
 
 f/g. 80. 
 
 Fftj.ai. 
 
 FiQ.82. 
 
 me, in the moulding ring, then dusted freely with lycopodium, and the 
 rubber ring adjusted for the purpose of securing the counter-die (Fig. 80), 
 which is poured with fusible alloy. 
 
 A higher fusing metal than any of the fusible alloys is necessary for 
 casting the cusp-button m order to preclude the probability of melting it 
 in securing the counter-die. 
 
92 
 
 In the process of forming the cusp with these dies (Fig. 8i), the 
 swaging should be done in the counter-die by the use of an ingot of lead, 
 or a large buckshot, until closely adapted, after which the surplus gold 
 should be cut away and the cusp-button used for the final sv/aging only, to 
 bring out the finer lines. These cusp-buttons may be preserved and found 
 useful wherever occasion admits of the use of ordinary and typical dies, 
 such, for instance, as the absence of occluding and adjacent teeth. 
 
 Another method somewhat more simple is to secure the mould as 
 indicated, and then adjust the rubber ring and pour the die of fusible 
 alloy. The surface is then dusted with lycopodium or coated with a solu- 
 tion of whiting in alcohol, the rubber ring readjusted, and a counter-die 
 of the same metal and dimensions secured. (Fig. 82.) 
 
 While this will answer the purpose, if the swaging is done in similar 
 manner, the tendency of stretching and probability of tearing the gold 
 
 will be increased, especially if the cusp is very deep, because of the diffi- 
 culty of swaging and conforming gold, or any metal, to any given or de- 
 sired shape between two surfaces of like and equal resistance, in which, 
 respect lies the advantage of the former method. 
 
 In the process of swaging, the surfaces of the dies 
 Swagiltd, should be oiled to facilitate the procedure, and pre- 
 
 vent sticking. A convenient method of preventing 
 the defacing of the gold is to stretch a piece of rubber dam over it before 
 driving into the counter die. This also avoids any coating of the die metal 
 from adhering to the surface o^ the gold. The chances of tearing the gold 
 may be reduced to a minimum by first swaging a few layers of heavy 
 tinfoil covered by the rubber dam. This slightly compresses the metals 
 and affords space for the gold between the two surfaces of the dies, 
 and it should first be carefully worked down into the counter die with 
 
93 
 
 a small blunt-pointed piece of wood. The gold 
 used should be of the same karat and color as the 
 band, and of 28 gauge thickness, as it is to be 
 subjected to considerable stretching. It should 
 be cut somewhat larger than the diameter of the 
 cusp to be formed, and frequently annealed dur- 
 ing the process ; and a round or disk-shaped piece 
 of plate will yield more readily to the desired 
 conformation between the dies, with, less ten- 
 dency to overlap at the angles; and all unneces- 
 sary surplus should be removed before the final 
 swaging. Steady and uniform pressure, such as 
 would result from the use of a press of adequate 
 power, would be productive of better results, in 
 the absence of which a heavy hammer and direct 
 blow will answer. 
 
 When the swaging has 
 Jfdjusiing Cusp. been completed, the edge of 
 cusp should be carefully 
 trimmed down to the line marking its point of 
 contact with the band, which should be outlined 
 in the gold. This point can be approached with 
 small curved crown shears, but the final trimming 
 should be done with a fine flat-surface gold file, 
 and may be best and more uniformly accom- 
 plished by holding the file steady and carrying 
 the cusp backward and forward over its surface. 
 The plaster cusp should then be removed from 
 the band, and the latter adjusted to place on the 
 articulator. After filling the interior of the band 
 with wax to sustain the cusp, it should be con- 
 secutively trimmed and tried to place until the 
 edges approximate evenly, and the desired 
 occlusion is obtained and proven by the firm 
 closure of the articulator. (Fig. 83.) 
 
 The necessary re-en- 
 Somerlltfl Cusp. forcement of the cusp to 
 fortify it against constant 
 and continued attrition may be done with 
 solder simultaneously wath its attachment to 
 the band, although no objection is offered to 
 filling the cusp with solder previous to its 
 
 ■ 
 
 
94 ■ 
 
 subsequent attachment if done with the same karat that would be 
 indicated and used in the joint. During" the process of solder- 
 ing, the relation between cusp and band should be securely sus- 
 tained. This can be best accomplished by the use of automatic pliers de- 
 signed for the purpose as indicated in Fig. 84, the use of wire being objec- 
 tionable for the same reasons previously mentioned in connection with 
 soldering the band. 
 
 The parts should be treated to the acid bath, freely washed with water, 
 and adjusted in the pliers. Flux should then be applied to the joint and 
 fused, and the parts united with 22 or 20 karat solder. The necessary 
 re-enforcement may be obtained with 18 karat solder. In case of a 
 perforation of the gold as a result of swaging, the same should be first 
 
 Fi<j.85, 
 
 filled with foil, when no trouble will be experienced in covering it over 
 or filling it in with solder. 
 
 When the soldering has been completed, the 
 
 Tinisbins. crown should be again treated to the acid bath to 
 
 dissolve remaining borax, then dressed down with 
 
 carborundum stones and disks in the engine, and finally polished on the 
 
 lathe. 
 
 While no special or particular advantage is af- 
 Solid Cast €u$D$. forded by the formation of a solid or cast cusp, 
 excepting that the presentation of a faulty or inaccu- 
 rate occlusion may be remedied by grinding freely without exposing the 
 solder, yet many prefer to pursue this method. When such procedure 
 seems desirable, the plaster cusp, after carving, should be left Hush and 
 continuous with the outside edge of the band. 
 
 The moulding ring should be filled with mouldine, and the mould of 
 the cusp secured on a line with the edge of the band. This should then 
 
95 
 
 be placed over the Bunsen burner and allowed to remain until the mould- 
 ine becomes hard. Asbestos of adequate thickness to accommodate the 
 depth of the cusp may also be used for the mould by saturating it with 
 water until a suitable imprint of the plaster cusp can be made in it, after 
 which it should be dried in the same manner. Scrap gold of sufficient 
 quantity, sparingly fiuxed, should be fused in the mould, and, when 
 molten, may be easily cast by quickly pressing it into the matrix with a 
 smooth surface of carbon or steel large enough to cover the entire area of 
 the cusp. (Fig. 85.) The principal objection offered to this method is 
 the time ordinarily required to trim and file the surface until a perfect 
 approximation with the band, and the necessary requirements of occlu- 
 sion are obtained. 
 
 €u$p Tormation without models. 
 
 The same detail of procedure is applicable to the formation of cusps 
 without the use of models or articulator. The results, however, while 
 perhaps occasionally as artistic, are not so accurate, because no guide for 
 
 obtaining the correct length of cusps is present, and no opportunity is 
 afforded for proving the articulation and occlusion in the final adjust- 
 ment and attachment of the cusps to the band, unless it be done directly 
 in the mouth. 
 
 When the employment of such a procedure may seem mdicated, of 
 when it may be desirable or necessary to complete the crown at a single 
 sitting, the band in position on the root may be filled with a sufficient 
 quantity of plaster, in the plastic state, or with modeling compound, and 
 the teeth closed directly into it. After thoroughly hardening it should be 
 removed, the surplus trimmed away even with the band, and the desired 
 and typical shape and form then given it by carving, as is consecutively 
 illustrated in Fig. 86, when the dies or mould may be obtained in the 
 manner outlined, and the crown finished, as indicated. 
 
 Jlsb's Crown Swaging Dei^ice. 
 
 Ash's crown swaging device, which consists of a cylinder and 
 plunger, and a soft rubber or hydraulic pad, will be found quite useful 
 
96 
 
 for swaged cusps, because of eliminating the necessity for the use of any 
 counter-die, or of swaging between two surfaces of metal, and, by pre- 
 venting any rebound, displacement or defacing of the gold during the 
 process. , 
 
 In its use the mould from which the die is secured must be obtained 
 in a moulding ring of suitable dimensions, to render it of a size corre- 
 sponding to the interior diameter of the cylinder. These are included in 
 an outfit suggested by Dr. E. G. Christiansen, of Dremmen, Norway, 
 and manufactured by C. Ash & Sons. 
 
 Ficj.QT, 
 
 When the die has been secured with fusible alloy it should be placed 
 in the cylinder, the gold annealed and placed in position, and the soft 
 rubber or hydraulic pad then inserted. 
 
 The plunger is then adjusted, and, upon being driven into the cylin- 
 der, results in the swaging being easily and quickly accomplished, with- 
 out danger of tearing or defacing the gold. 
 
 If the cusp-button method of dies has been employed, and the button 
 afterward used only to bring out the finer and more definite lines, the 
 swaging may be done in the counter die in the same manner 
 
 (Fig- 87)- 
 
97 
 
 Die and Die Plate Itletboils. 
 
 The advent of the die and the die-plate systems was, primarily, the 
 outcome of a desire for ohtaining more natural and artistic results in the 
 process of cusp-formation than was then possible by pursuing the primitive 
 method. Originally, efiforts in this line were confined to soldering a flat 
 surface of gold to the band, and then building the cusps at various points 
 upon this surface with small globules of scrap gold, or pieces of triangu- 
 lar platino-iridium wire, attached with solder ; or with solder alone, and 
 subsequently grinding to the desired form and occlusion. 
 
 While many of these somewhat crude, inaccurate and inartistic 
 efforts were successful from the standpoint of serviceabilitv and useful- 
 ness, the introduction of dies soon followed. These were designed to 
 serve as a means of securing more artistic results, and as a time-saving 
 procedure. 
 
 The first productions in this 
 Tndit>idual Dies. line were individual dies, ob- 
 tained directly from the natural 
 teeth. For this purpose suitable extracted teeth were 
 selected, and mounted in a base of plaster. This was 
 then trimmed to favorable shape for securing a mould 
 in sand, from which a casting was made of zinc. 
 
 Plate gold was then swaged to conform with tl 
 outlines of the natural cusps by driving the die into 
 smooth surface of lead, or an old discarded counter-di 
 
 This method was productive of so great a degre 
 of improvement over the former procedure as to sut 
 sequently induce the supply-houses to manufactuit 
 these dies in sets of various numbers, and made of 
 brass in order to be more permanent and indestructible 
 (Fig. 88). 
 
 Because of the immediate necessity for a suita- 
 
 Dle-PlafC$. ble counter-die, and of the advantage of combining 
 
 a larger variety of cusp-forms into more convenient 
 
 and compact order, the introduction of the die-plate was a natural 
 
 sequence. 
 
 These comprise various numbers of cusp-moulds in a brass or steel 
 castmg. In their use the swaging is easily and quickly accomplished by 
 driving the disk of gold into the mould selected to best approach the re- 
 quirements, with an ingot of lead or alloy of lead and tin. Ingots for the 
 purpose may be previously cast in any quantity, and of adequate and con- 
 venient sizes by the use of a hub-mould designed for, and usually accom- 
 panying, the die-plate (Fig. 89). Ordinary buckshot, however, are easy 
 
 Fi 
 
 '1 
 
98 
 
 to procure, and, if of suitable size, will answer the purpose nicely. The 
 steel plates may also be thus employed, or may be used to produce solid 
 cusps by driving an ingot of scrap gold into the mould selected. 
 
 While these plates are still in common use their value and range 
 of application increases in proportion to the number and variety of cusp- 
 forms contained, and their limitations, of course, decrease in inverse 
 ratio. 
 
 In their use the mould should be selected which 
 
 Jlt)p]ication. best represents the individual tooth to be crowned^ 
 
 and meets or approaches the size of the band. The 
 
 requirements of occlusion must be secured in the fitting and adjustment 
 
 of the cusps to the band, which can only be observed, of course, after 
 
 swaging the cusps. 
 
 With cusps formed by any die-plate system or 
 
 JldjUStins method the best and most accurate relation can be 
 
 Witl) models* secured with models mounted upon the articulator. 
 
 Opportunity is thus afiforded for trimming the band 
 
 Fi<j.d9. 
 
 or the cusps, until their approximation admits of a favorable occlusion, 
 which can be noted upon the lingual as well as the buccal surfaces. 
 
 More perfect occlusion may often be obtained by depressing the 
 cusps with a blunt instrument, or piece of wood ; or, if necessary, by 
 building up, wherever indicated, with a high grade of solder. Small 
 globules of scrap gold or pieces of gold or platinum wire facilitate such 
 procedure by affording a guide as to the desired formation and location, 
 and by requiring the control of less solder in their attachment. 
 
 When the requirements of occlusion have been thus observed, an 
 effort should be made to closely approximate the edges of cusps and 
 band. This may be done by adjusting the one to the other with pliers,, 
 if care be exercised so as not to distort the shape of the band and destroy- 
 its contact and alignment. Any necessary filling in or subsequent con- 
 touring may be done with solder in the final attachment. Where a con- 
 siderable space exists between the two portions, the process of soldering 
 is facilitated by burnishing a piece of thin pure gold plate, or packing^ 
 foil gold into such spaces. 
 
99 
 
 In emergencies, or where it may seem desirable 
 HdjUSdng to complete the crown without models, and secure 
 
 Without models. the adjustment in the mouth, the fitting may be 
 facilitated by filling the interior of the band with 
 wax to temporarily sustain the cusps during the process. When the 
 parts have been approximated, a more perfect occlusion may often be 
 obtained by tacking the cusps to the band at one point with a very small 
 bit of solder, and then replacing the crown and having the opposing 
 teeth closed firmly into it, after which the soldering may be completed, 
 and the necessary reinforcement given. If the requirements are particu- 
 larly difficult, the process may be further facilitated by swaging the cusps 
 of 30 gauge pure gold. This is so much more yielding and will offer so 
 little resistance to the closure of the teeth into firm occlusion, as to insure 
 moderately accurate results, but such cusps should be attached with a 
 very high grade of solder, as the extreme softness of the gold will soon 
 result in its exposure. This procedure is equally applicable, of course, to 
 the adjustment of cusps formed by any system or method employed. 
 
 1)ollin9$wortb System. 
 
 Ihe great variation in the size, shape and depth of cusps necessary 
 to meet or approach the requirements of this style of crown construction, 
 and the previous absence of any system, or definite detail in the work, 
 resulted in the introduction of the HoUingsworth System, devised by Dr. 
 J. G. HoUingsworth. 
 
 This was the first system embracing a detailed line of procedure in 
 the construction of gold crowns, and because of including a large variety 
 and selection of typical forms, of its simplicity, and of being so great an 
 improvement over former methods, it is much used. 
 
 It comprises about two hundred typical occlusal forms in the shape 
 of cusp-buttons, and a good selection of moulds of the buccal surfaces of 
 bicuspids and molars, and of the labial and lingual surfaces of the anterior 
 teeth. 
 
 Those for the buccal surfaces of bicuspids and molars are designed 
 for the purpose of securing a more artistic shape in these surfaces of the 
 band by swaging, or for gold reproductions of the entire tooth. For the 
 former purpose, however, such procedure by any system is unnecessary, 
 because of the time consumed, and of the possibilities for otherwise, and 
 more quickly securing a proper and equally artistic shape. While such 
 moulds may often be found useful for obtaining all gold dummies for 
 bridge construction, those for the anterior teeth are practically useless, 
 because of the limited indications for the application of such crowns. 
 
 The variety, form and convenient shape of the cusp-buttons, how- 
 
lOO 
 
 ever, affords for them a more or less extensive range of application and 
 usefulness. They are made of a metal which is moderately indestructible, 
 and are used only for the purpose of forming- the die for the subsequent 
 conformation of the gold by swaging, or for securing the mould in asbes- 
 tos for the purpose of obtaining solid cast cusps, as previously indicated. 
 
 The convenient size of the cusp-buttons possesses the advantage of 
 facilitating the selection of the one most favorable to meet the require- 
 ments, which may be accomplished by trying to place upon the band, on 
 the articulator, or in the mouth. 
 
 Aside from the forms, the system consists of a steel moulding plate 
 and suitable rubber moulding rings. 
 
 When the cusp-button which best represents the 
 
 Jlpplication. tooth, and meets the requirements of occlusion and 
 
 approximation with the edge of band, has been 
 selected, it should be deposited upon the moulding plate, and the rubber 
 ring placed around it. Fusible alloy should be then melted and poured 
 into the ring. In pouring, it should be directed immediately upon the 
 center of the cusp-button,'*"in order to prevent an imperfect die, or one 
 not entirely surrounded with metal. 
 
 When the fusible alloy has crystallized, it should be cooled by dip- 
 ping into water, and the rubber ring then detached. The cusp-button 
 may be then easily separated by gently tapping, and replaced in the tray, 
 and the die is ready for the swaging of the gold. This is accomplished 
 in the manner indicated, by the use of a buckshot, or ingot of lead, driven 
 to place with a swaging hammer, after which the surplus may be trimmed 
 away, and the cusps finally adjusted to proper relation with the band and 
 occlusion, and then soldered. 
 
 The use of these cusp-buttons offers the additional advantage of 
 affording opportunity for modifying or improving the occlusion when 
 indicated, by building the cusps up with mouldine at the desired points, 
 and to the desired depth, before pouring the die. Also, in cases where 
 the band may be so short as to require a deeper cusp, this may l^e easily 
 secured by raising the cusp-button on the moulding plate with a base of 
 mouldine of sufficient thickness to make up the deficiency in depth, and 
 trimmed to closely follow the outline, before pouring the die. 
 
 m\mr% system. 
 
 One of the most modern inventions in die-plates, and processes of 
 swaging, and one possessing some new and good features, has been re- 
 cently introduced in Millett's System. 
 
 This consists of a large die-plate comprising about four hundred 
 raised moulds of cusp-forms, and buccal and labial surfaces, sy=<-emati- 
 
lOI 
 
 cally arranged in sizes, and for each side of the mouth, and the necessary 
 apparatus for swaging. 
 
 While the forms are similar in size and shape to those of the Hol- 
 lingsworth System, the die-plate offers a greater range of application in 
 a larger variety for selection, and the advantage of each one being an 
 integral part of the plate, which overcomes the possibility of the disar- 
 rangement or loss of any of them. 
 
 This, together with the method of securing the die, and the process 
 of swaging, without doubt affords greater simplicity and quicker results, 
 but the important feature of not being able to adjust the cusp-forms to 
 position on the band, as an aid in their proper selection, is a disadvantage. 
 
 The apparatus for swaging includes a cylinder and plunger, and a 
 bed-plate and soft rubber block, which are similar to Ash's crown swag- 
 ing outfit. 
 
 The bed-plate is designed for the purpose of 
 
 Jlpplication. holding a sufficient quantity of ordinary sealmg- 
 
 wax to secure a die of any of the individual moulds, 
 and fits accurately in the cylinder. 
 
 The sealing-wax contained in the bed-plate is softened by passing 
 through a flame, and then pressed firmly over the form selected to be 
 duplicated in gold, and which is calculated to be the nearest approach to 
 the requirements. 
 
 This gives an accurate impression of the form, in the wax, which, 
 after chilling in cold water, is sufficiently hard to answer the purpose of 
 a die. 
 
 This is placed in the cylinder, the gold annealed and placed on top 
 of it, the soft rubber block inserted, the plunger placed over all, and the 
 swaging accomplished by driving the plunger into the cylmder with a 
 moderately heavy swaging hammer. 
 
 In cases where a deeper cusp-form is desired, or necessary, a rim of 
 warm sealing-wax may be moulded around the edge of the imprint until 
 sufficient increase of depth is obtained, before swaging. Where a more 
 shallow reproduction is indicated, the sealing-wax may be trimmed or 
 pared down accordingly ; or, if the summits of one or more of the indi- 
 vidual points or cusps need to be made more pronounced, the die may be 
 deepened at such points with a sharp bur or suitably shaped cutting in- 
 strument. 
 
 Cowry System. 
 
 This system, devised by Dr. H. S. Lowry, departs from other methods 
 where moulds are used, and, like the original die-plates, comprises the 
 actual dies to be used in the process of swaging. 
 
102 
 
 The improvement lies in the more extensive selection, and the sup- 
 plemental trial caps which represent the exact size and formation of the 
 dies. 
 
 The dies are individual in character, made of a practically indestruc- 
 tible metal, and each one is numbered. The trial caps are numbered cor- 
 responding with the dies of which they are counterparts, and are pro- 
 vided with a projecting stem, which facilities holding and handling 
 them in their adjustment to the band, in the process of selecting the one 
 best suited to the requirements. 
 
 The system includes a moderately good selection of about sixty dies 
 of cusp-forms ; and a smaller number of the buccal surfaces of bicuspids 
 and molars, and the labial surfaces of the anterior teeth, with correspond- 
 ing complement dies, together with a "stamper" for swaging, and solder- 
 ing pliers for general use. 
 
 The trial caps are adjusted to position on the 
 
 JTpplication, band, until a selection is made, of the one which best 
 
 meets the requirements. The number of this is 
 noted, and the corresponding die selected. The surface of the die should 
 then be slightly oiled, and the gold cut, annealed, and placed over it, and 
 then adjusted to position in the "stamper." A buckshot or piece of lead 
 of suitable proportions should then be placed upon the gold, and the 
 plunger of the "stamper" brought in contact. 
 
 The plunger is held quite securely in any position by means of fric- 
 tional contact, which facilitates the swaging in preventing the rebounding 
 of the die, or the slipping or moving of the gold or lead during the pro- 
 cess of driving it down by the use of a swaging hammer. 
 
 A special die, containing two depressions of different sizes, is pro- 
 vided for improving the occlusion when indicated, by lengthening or 
 deepening the cusps at any desired point. After the cusps have been 
 swaged, the point to be raised or deepened should be placed over the hole, 
 and further swaged to the necessary extent by the use of a blunt piece of 
 wood of suitable size. 
 
 Baird System. 
 
 Another recent device in this line is the system and method designed 
 by Dr. W. H. Baird. 
 
 This consists of a heavy pair of swaging pliers, with parallel jaws, 
 one of which is grooved to admit of slides which support the dies. 
 
 The dies are raised and individual in character, made of a compara- 
 tively indestructible inetal, and include about two hundred and fifty mod- 
 erately good forms. These comprise a good selection of cusp-forms, and 
 
103 
 
 a proportionate number of the buccal surfaces of bicuspids and molars, 
 and the labial and lingual surfaces of the anterior teeth. 
 
 When the selection of the form calculated to 
 
 Application. best meet the requirements has been made, it is then 
 
 placed in position on the slide, and the latter ad- 
 justed to the grooves in the pliers. 
 
 The gold is then annealed, placed upon the die, and covered with a 
 pad of soft rubber, or piece of sheet lead of adequate thickness f about 3-16 
 of an inch), and dimensions, to serve as a counter-die. The pliers are 
 then closed and held together with sufficient firmness to prevent any re- 
 bound during the process of swaging, which is accomplished with a 
 hammer. 
 
 The flat base to each die precludes any opportunity for accurately 
 adjusting to the band, in making the selection; and the system affords 
 no provision for altering the cusp reproductions to more perfectly meet 
 the requirements of occlusion, depending upon the varietv and general 
 application of the dies for this ]:)urpose. 
 
 Seamless Itletbod. 
 
 The seamless method comprises forming the entire crown with one 
 piece of gold, by swaging, and, while many systems for this particular 
 style of construction have been devised, and are used, a close observation 
 of the relative advantages and disadvantages as compared with the sec- 
 tional method fails to afford any real or practical evidences of special 
 merit in this process. 
 
 It is claimed by those using and advocating this method that a closer 
 reproduction of the natural tooth form is possible, and that greater oppor- 
 tunities for more pronounced contouring are afforded, from which asser- 
 tions it is deduced that more artistic results may be obtained. 
 
 As such results from any metJwd of procedure, however, are equally 
 dependent upon the skill, ability and conscientious efforts of the operator, 
 and, as the presence of a joint between cusp and band is in no way objec- 
 tionable if the prerequisites previously mentioned have been observed, any 
 actual or practical foundation for such a claim is scarcely apparent. 
 
 If it were still necessary to depend upon a limited selection of cusp 
 forms, which were difficult to adapt to the average properly contoured 
 band without the use of considerable solder and much filling in, some ad- 
 vantage might be possessed by a method which would afford a smooth 
 continuous crown, but, in view of the possibilities already outlined in this 
 connection, the real value of the seamless method will doubtless always 
 remain more appreciable to the "dental laboratories," and others commer- 
 cially interested, than to the average practitioner of ordinary skill. 
 
I04 
 
 A summary of the possible advantages of this 
 
 Jfdvantases. method presents but two special features : First, the 
 
 opportunities for obtaining contour, and, second, the 
 absence of a joint or seam of solder at any point. 
 
 The first feature needs no consideration, because, as has been pre- 
 viously asserted, the possibilities of, and opportunities for, contouring, 
 are not entirely dependent upon the process employed, and in no way ex- 
 ceed those offered by the sectional method in so far as the actual require- 
 ments are concerned. 
 
 In considering the second feature, the absence of a joint or seam of 
 solder may be proclaimed as an advantage in three instances of detail. 
 First, in eliminating the possibilities of the subsequent discoloration of the 
 solder in the joint, when subjected to the action of the secretions. Second, 
 in the construction of a platinum crown which is to serve as an abutment 
 for porcelain bridgework. Third, in the construction of a gold crown for 
 the bicuspids where a porcelain facing is to be subsequently in- 
 serted. 
 
 In the Urst instance, if the edges to be united are closely -fitted and 
 approximated, the quantity of solder in the joint is so infinitesimal that 
 if a high grade of similar color be used, and the crown then well finished 
 and polished, no opportunity will be offered for any subsequent discolo- 
 ration ; hence, no special advantage is apparent. 
 
 In the second instance the same advantage may be readily obtained 
 by permanently overlapping the edges of the band in making the joint, 
 and closely approximating the edges of cusp and band, and then using- 
 platinum solder in their union. This will preclude the re-fusing or un- 
 soldering of the parts in the furnace daring the process of fusing the 
 porcelain ; and the additional thickness of platinum which may be used 
 when the sectional method is employed adds materially to the necessary 
 strength which such a crown must possess in that particular portion of it 
 zvhich surrounds the root. 
 
 In the third instance the advantage is perhaps least imaginary, but if 
 the joints of the sectional crown intended for such a purpose are made as 
 has been indicated, the subsequent attachment of the facing with a lower 
 grade of solder may be done without danger of re-fusing them. This may 
 be also further prevented, if any doubt exists, by previously coating the 
 solder in such joints with a solution of whiting in water or alcohol before 
 attaching the facing. 
 
 The features of this style of construction which 
 
 Di$(ldvantildC$. are of a more or less pronounced disadvantage, in a 
 general way, lie in a consideration of the essentials of 
 time, strength and accuracy of adaptation. 
 
I05 
 
 The detail being more circuitous, a greater 
 
 Z\mt, length of time is necessarily consumed in the process. 
 
 If better results by this method than by any other 
 
 were possible, this should not necessarily be a consideration, but it Ijecomes 
 
 a matter of much concern when equally good results may be obtained by 
 
 another method in less time. 
 
 The fact that a much thinner gauge of metal 
 Strength. must be used to begin with, and that it must then be 
 
 subjected to considerable stretching, is conspicuously 
 a disadvantage, because of the extreme thinness and consequent weak- 
 ness of the finished crown. While sufficient re-enforcement of the occlusal 
 portion rnay be afterward made, the band, where equal and uniform 
 strength is usually required, must remain inherently weak, or be stiffened 
 at the expense either of the root or of the contour. 
 
 As a degree of accuracy must be insurefl in the 
 JIdaptation. process, the adaptation to the root of a primary or 
 
 temporary band is necessary. This, however, in one 
 particular is a disadvantage, because, irrespective of however accurate it 
 may be, each subsequent reproduction of a given form is less accurate than 
 the original, unless they may be stamped in indestructible and unyielding 
 dies, which equalities are not possessed by fusible alloys, such as are used 
 for the dies in this work. 
 
 Detail of €on$tnictiOH. 
 
 While there are many and varied methods of detail for the construc- 
 tion of seamless crowns, but one general line of procedure will be found 
 to give results which are sufficiently reliable to insure an approach to the 
 necessary degree of accuracy. 
 
 This constitutes taking a measurement of the root, after its prepara- 
 tion, and making and fitting a primary band, the exact shape and con- 
 formation of which is then subsequently reproduced in the finished crown. 
 
 The primary band may be made, preferably, of 
 Primary Band. 32 gauge copper, cut to ordinary width, the exact 
 length of the measurement, with straight edges, and 
 soldered as usual. Or a seamless band may be made by selecting the 
 drawing punch over which the circular measurement will fit most closely,- 
 and then drawing a blank down to this same size. By then punching out 
 the top, a seamless band results, which approximates the size of the root 
 as closely as the measurement fitted the punch. Those preferring the latter 
 usually have a selection of these blanks already drawn to various sizes, 
 which is an economy of time. 
 
 When the band has been made, it should be trimmed and fitted to the 
 
io6 
 
 root with the same degree of care and precision as though it were intended 
 for permanent use. It should then be cut away upon the buccal and lingual 
 surfaces until but a narrow rim remains, allowing the approximal surfaces 
 to remain sufificiently wide to be closely adapted to the adjacent teeth. 
 (Fig. 90.) By so shaping it, a perfect restoration of the contact points 
 may be made, and increased opportunity is afforded for forming, shaping, 
 modifying or exaggerating the buccal and lingual surfaces as may be 
 desired. 
 
 I When the fitting and trimming has been com- 
 
 BWC and Tm^jresslOlt. pleted, the bite and impression should be taken. 
 While this is often done at one and the same time, 
 with wax or modeling compound, a separate bite in wax, and impression, 
 in plaster is preferable, and safer, because of the uncertainty of replacing 
 the band in its exact and proper position in the former materials. 
 
 When these have been secured, and the band accurately replaced in 
 position in the impression, the model should be obtained, the bite adjusted 
 
 fiq. 90. 
 
 Ficj.91. 
 
 to it, and both securely mounted upon the articulator. After separating, 
 the surfaces of the adjacent and occluding teeth should be varnished and 
 the band and space filled with thin, well-mixed plaster, and the articulator 
 firmly closed. 
 
 This portion of the procedure and the subsequent carving and shap- 
 ing of the plaster is almost identical with the detail previously outlined in 
 carving cusps, and all of the necessai / artistic work must, of course, be 
 done at this stage, because the permanent crown will be a close reproduc- 
 tion of this model. 
 
 The only difference in the detail is that the form and alignment of 
 buccal and lingual surfaces is obtained by shaping the plaster, instead of 
 contouring the wider band, and that it should be done zvithouf detaching 
 the band from the model, and also that the plaster should be left flush, 
 even and continuous with the band, instead of being trimmed to expose 
 its edge as for a swaged cusp. 
 
i07 
 
 When the necessary carving has been completed, 
 Prcparlnfl models, the model should be detached from the articulator, 
 and trimmed down until only enough remains to form 
 a base for the crown, as indicated in Fig. 91. 
 
 This plaster base is then trimmed, so as to be favorable for, and 
 facilitate handling during the process of securing the die, and to give 
 
 (Half Size) 
 
 adequate depth or body to the latter. The plaster base immediately ad- 
 jacent to the cervical portion of the band should be cut away sufficiently 
 to expose the full thickness of the edge, which thus stands out in the die 
 and indicates the outline, after swaging, to which the finished crown 
 should be trimmed. (Fig. 92.) 
 
 Various designs of casting flasks have been de- 
 Castiltd TIaskS. vised for the purpose of serving as a matrix in se- 
 curing the dies with fusible alloy. Much similarity 
 of principle exists between them all, and the one which is a part of the 
 
 Seamless Crown Outfit, manufactured by the Consolidated Dental Manu- 
 facturing Company (Fig. 93), is simple and conveniently adequate for 
 such purposes; though those designed by Dr. W. H. Trueman (Fig. 
 94a) (which must be held in a vise while swaging), and the Berry Dental 
 Manufacturing Company (Fig. 94b), will be found to favorably meet 
 the requirements. 
 
io8 
 
 In securing the die, the plaster model containing 
 
 Dies. the crown should be thoroughly dried^ to prevent 
 
 any bubbling of the metal, dusted with lycopodium, 
 
 and then placed on a smooth level surface of steel or mouldine, so as to 
 
 rest firmly and sustain a perpendicular position and the casting flask 
 
 placed over and around it. 
 
 A piece of thin cardboard should be adjusted to the grooves in each 
 side of the flask, and trimmed to follozv the outline oi the model (Fig. 95) . 
 These are intended to facilitate the subsequent separation of the die into 
 two lateral halves, but should not come in contact with the model at any 
 point. 
 
 The flask should then be filled with fusible alloy, poured when in the 
 
 Fj<^.95 
 
 plastic state, in order to insure a smooth, well-defined casting, and to 
 facilitate the separation of the crown from it. 
 
 Another method is to first fill the flask with the molten alloy, after, 
 adjusting the cardboard, and then firmly force the model into the center 
 of the metal just before the process of crystallization takes place, holding 
 it in position until it has thoroughly hardened. Tf done just at the right' 
 moment, this method is productive of good results, but the procedure is 
 somewhat more uncertain than the former. 
 
 After chilling the metal with cold water, it should be removed from 
 the flask and the cardboard detached. By inserting a chisel into one of 
 the grooves thus formed, and striking it a moderate blow, the die may be 
 easily separated into two parts. (Fig. 96.) The model is now removed 
 from the die, and the parts may be readjusted to proper relation, and re- 
 placed in the flask, which possesses a guiding notch to insure proper read- 
 
I09 
 
 JLislnient, and which liolds them securely together during the process of 
 swagii^g the crown. 
 
 The seamless l^lank, or cartridge, which is to he 
 Terming Blanks. conformed to the desired outline of the permanent 
 
 crown, hy swaging, should now be formed. 
 For this purposes all of the ''Systems" or "Outfits" contain or include 
 
 Ficj.96. 
 
 a steel plate with perforations, the diameters of which range consecutively 
 from the largest to the smallest useful sizes, with a set of steel punches 
 correspondingly graded. 
 
 A disk of 22 karat gold, not thicker than 30, or thinner than 32 gauge, 
 should be procured. These are prepared by the supply houses in various 
 sizes. The two sizes most convenient for molars and bicuspids are illus- 
 
 //•y.97. 
 
 trated in Fig. 97 and may be symmetrically cut from plate by using an 
 accompanying copper disk, or the end of a drawing punch as a guide. 
 These disks are formed into the blank by driving them through the 
 holes in the plate with the drawing punches, beginning with the largest 
 size and passing through each consecutive perforation until the blank is 
 reduced to a size which will admit of its being gently forced into the die. 
 
no 
 
 If a seamless primary band has been used, the size of the drawing 
 punch last used in its formation will, of course, indicate the size of the 
 blank required for the crown, and the size or number should be desig- 
 nated or remembered. 
 
 The gold should be annealed often during the process to prevent 
 tearing, and slightly oiling the end of the punches and the interior of the 
 perforations will be found advantageous in facilitating the drawing and 
 preventing the blank from sticking to the former. 
 
 The drawing press designed for this purpose by Dr. W. M. Sharp 
 may be found useful. It can be securely fastened to the bench and the 
 blank is formed by means of a screwpress instead of driving, which re- 
 
 sults in its being drawn more evenly and uniformly than by intermittent 
 blows. 
 
 When the blank has been formed to the desired 
 
 Swaging* size, it should be cleaned in the acid bath, and then 
 
 annealed. The surface of the die should be oiled 
 
 and the blank gently forced well down into place with a blunt piece of 
 
 soft wood of suitable size, and a small hammer. 
 
 Any excessive surplus of band may be previously trimmed away to 
 facilitate swaging, but care should be exercised not to trim too much. 
 
 The interior of the blank should be filled with a substance which will 
 spread readily and evenly when pressure is applied, but which may be 
 easily removed at any time during the process. 
 
 Oiled birdshot, cornmeal, pumice stone, small cubes of modeling com- 
 pound, base-plate gutta percha cut into small pieces, pledgets of moistened 
 cotton, or cotton previously saturated with melted wax, stiff putty mixed 
 with soapstone and tin foil rolled into small globules are used. 
 
 The swaging is then accomplished by driving a blunt piece of wood, 
 or the end of a drawing punch a few sizes smaller, into the blank thus 
 
Ill 
 
 filled. If necessary, the gold may be removed and annealed several times, 
 though once after starting and during the process is all that is usually 
 required. 
 
 When the swaging has been completed, the sur- 
 
 Jldaptina plus should be trimmed away to closely follow the 
 
 and Rc-Cnforclttfl, cervical outline indicated in the band, and the crown 
 
 sUglifly heated and subjected to the acid bath, when 
 
 it may be re-enforced with a high karat of solder or a lower karat uf 
 
 plate gold, rolled lliui, and finished. 
 
 If the finished crown should be too large, it may be reduced with 
 pliers before re-enforcing, or if iiiucli too large as a result of compressing 
 the walls of the die during the process of swaging, it may be first cut in 
 two lateral halves, left in the die, and another crown swaged inside of it ; or 
 if too small, which is rarely the case, it nia_\' be stretched sufficiently with 
 pliers. Where some expanding or compressing of the bulbous portion may 
 be indicated in order to improve the contact with adjacent teeth, the rotary 
 point contouring pliers designed bv Dr. C. W. Miller will be found useful 
 (Fig. 98). 
 
 While many of the various "systems" provide means for securing 
 the model from a selection of typical forms of approximate sizes, from 
 which the dies are made ; and for securing the outline of the occlusal sur- 
 face by subsequently swaging in a typical die-plate, or other similar man- 
 ner, the possible results obtained from such methods do not merit con- 
 sideration because of being but little, if any, more accurate than ordinary 
 readv-made crowns. 
 
 J(ivtr$t Process. 
 
 In the preceding process it v\ill be noted that in the detail of swag- 
 ing, the blank is conformed to the outline of a mould or die of the orig- 
 inal model, by expanding or stretching it. This is termed the "inside- 
 out" method, and, while it is perhaps most generally used, the extrem.e 
 thinness of the finished crown, augmented by the necessity of begin- 
 ning with so thin a gauge, verv consistently occasions the objectionable 
 features already intimated in this connection. 
 
 As a means of overcoming such objections, and obtaining increased 
 thickness and strength, the rez'erse or "outside-in" process of swaging 
 has been devised. 
 
 In this method the blank is conformed by being compressed over a 
 metal reproduction of the original model, instead of being expanded to 
 meet the walls of. a mould of it. 
 
112 
 
 While the process of swaging is perhaps more 
 
 JldcantagC$« difficult to accomplish, the results are advantageous 
 
 in being productive of a heavier and more uniform 
 
 thickness of gold in the finished crown, and of greatly diminishing, if 
 
 not entirely overcoming, the probability of tearing it. 
 
 The result obtained by swaging the gold over 
 Disadvantages. the outside dimensions of a metal reproduction of 
 the original and desired form, would seem to be ob- 
 jectionable in that the crown so conformed must be somewhat larger 
 than the model. This, together with the tendency of the gold to over- 
 lap and knuckle here and there, during the swaging, are logical disad- 
 vantages, unless means are observed for overcoming them. 
 
 While the overlapping and knuckling may be easily avoided by care- 
 ful manipulation of the gold during the process, the difference in size 
 occasioned by the thickness of gold can be overcome only by using force 
 
 Fiq 99 
 
 FicflOO 
 
 enough in swaging to so compress the die by the impact as to compen- 
 sate for this thickness, or, by removing the primary band just previous 
 to reproducing the metal model. 
 
 In view of the characteristics of the lower melting fusible alloys 
 which are necessarily used, and of the thinness of the gold after being 
 drawn down to the recjuired size blank, it is possible that fairly accurate 
 results may be obtained by depending upon the compression of the metal 
 model from the force and impact of swaging; yet as this is more or 
 less uncertain, the removal of the band is the preferable procedure and 
 will afford the most positive and accurate results. 
 
 As the variation between this and the preceding 
 Procedure. method pertains only to the manner of securing the 
 
 dies, and to the process of swaging, the procedure 
 up to the point of obtaining the model is identical with that already out- 
 lined. 
 
"3 
 
 When the crown lias Ijeen removed from the artic- 
 
 Origlnai mcd«l. ulator, and its plastor base trimmed to the required 
 
 form as previously indicated in Fig. 92, it should 
 
 then be reproduced in fusible alloy, instead of obtaining metal dies of 
 
 it in the form of a mould. 
 
 If the band is to be removed from the model, the plaster base should 
 be trimmed away sufficiently deep so as to leave a distinct cervical out- 
 line to guide in trimming the crown after swaging. The removal of the 
 band niav be easily accomplished b> cutting through it at the 
 narrowest and most convenient point, with a fine saw or file, after 
 which the entire plaster outline should be nicely smoothed down, and 
 then varnished. 
 
 The mould is obtained in the same manner 
 mould. formerl}- pursued in securing the dies, excepting 
 
 that it is made of plaster in- 
 stead of metal. The varnished model should be 
 adjusted to the casting flask, or similar device, 
 with pieces of cardboard /;; situ, Fig. 95, and thin 
 plaster then poured upon it. After crystallization 
 this may be broken open, the model'removed, and 
 , Ihe parts replaced and adjusted to the flask. 
 
 When the plaster has be- 
 Swaging model. come sufficiently dry, this 
 should be filled with fusible 
 alloy which melts at, or below, the temperature 
 •of boiling water. The metal model thus resulting. 
 Fig. 99, is identical with the original model, and 
 over this the blank of gold is conformed by vari- f/q 101 
 
 ■ous processes of swaging. 
 
 After drawing the blank to a size which will fit 
 Blanks. snugly over the swaging model, or securing the 
 
 same from the supply houses in ready-made form, it 
 should be first thoroughly annealed, as any subsequent annealing is pre- 
 vented after the swaging has been started, because of the necessity for 
 the destruction of the swaging model, by melting it. to admit of the re- 
 moval of the blank. 
 
 In conforming the blank to the outlines of the 
 Swaging. swaging model, considerable care must be exercised 
 
 to prevent knuckling and overlapping of gold by any 
 method employed. This can only be accomplished by frequently remov- 
 ing the crown and working out such places with a small riveting ham- 
 jner. Fig. 100. 
 
114 
 
 While several systems and devices have been 
 
 niCtbOdS. designed for the purpose of swaging crowns by this 
 
 process, the cylinder and plunger are the essential 
 
 features of the most useful ones, and even hydraulic pressure may be very 
 
 serviceably employed. 
 
 Ash's crown swaging device can be made to answer the purpose by 
 boring out the end of the plunger until it presents the form of a cone 
 equal in depth to that of the average crown, and a similar apparatus es- 
 pecially designed to meet such requirements constitutes a portion of the 
 seamless crown outfit manufactured by Mr. J. W. Place, of New York 
 City. The cone shape plunger is necessary in order to distribute the im- 
 pact evenly over the entire surface of the crown. 
 
 fjrr 102 
 
 In the use of such devices the blank should first be fitted over the 
 swaging model and gradually worked down to place with the riveting 
 hammer. This should be placed in the center of the cylinder and oiled 
 1:)ird-shot or. preferably, stiff putty freely mixed Avith lycopodium or soap- 
 stone, then packed closely around and over it until entirely submerged. 
 The plunger should now be inserted and gradually driven to place, re- 
 moving the crown frequently and working out the overlaps, until the 
 swaging is completed. 
 
 The apparatus designed by Dr. W. P. Scott, of 
 Scott's method. Chicago, which consists of an inverted cone shaped 
 cylinder, and straight flat-surface plunger, \\ith other 
 necessary accoutrements, is among the most complete, simple and mod- 
 ern inventions for this work, though it is similar to. and used much in 
 same manner as the Berry and Adam son outfits. 
 
 In the use of this system the blank is fitted to the swaging model 
 as indicated, and the occlusal surface first swaged by driving the same 
 into a surface of lead. After this portion of the crown is adequately 
 swaged, it is then placed in a matrix afforded between the two surfaces 
 of lead which are formed in a mould accompanying the outfit, and the 
 
whole then dropped into the cyHnder. The base and top of tlie latter 
 are adjusted, and the plunger inserted, (Fig. loi,) which upon being 
 driven deeper into the cylinder so compresses the lead matrix, and the 
 gold blank, as to closely conform it to the outlines of the swaging model, 
 with a minimum tendency to tear or overlap, and with a maximum and 
 uniform increase in the thickness of the gold. The lead matrix before 
 and after swaging, together with the crown in position in the latter, are 
 illustrated in Fig. 102. 
 
 When the swaging has been adequately accom- 
 TiniSbiltfl. plished by the method selected, very little finishing 
 
 is usually required. The crown should be polished 
 before detaching it from the metal model, after which the latter should 
 be melted by placing in boiling zvafer, and any adhering or remaining 
 particles removed by the acid bath. The surplus gold at the cervical por- 
 tion should then be carefully trimmed away to follow the outline indi- 
 cated, when the necessary reinforcement and final polishing may be 
 given. 
 
 Ficf.104-. 
 
 Jlpplicdtioii to Separatca molar Roots. 
 
 The presentation of cases where molar roots have become separated 
 at the bifurcation as the result of extensive disintegration of the crown, 
 and with each individual root remaining Urm in its attachment, is not an 
 infrequent or unusual occurrence. 
 
 In such instances the application of a crown will not only often 
 restore the roots to the former usefulness and supply the serviceability of 
 the original tooth for many years, but will also frequently preclude the 
 Impaired occlusion of the adjacent teeth which their natural gravitation 
 or tipping, as the result of the loss of such roots, would occasion. 
 
 This latter phase places a degree of importance upon the permanent 
 retention of these roots, which, particularly in early life, and especially on 
 fi,rst molars, makes such a procedure of inestimable value, and causes it to 
 be almost universally indicated wherever such a condition is found in 
 otherwise unbroken or well-filled arches, with the roots remaining rea- 
 sonablv firm. 
 
ii6 
 
 In the treatment of these cases the individual 
 
 Procedure. roots should be carefully prepared by observing the 
 
 therapeutic and mechanical requirements, and each 
 
 then built up separately with amalgam (anchored with a post, or by other 
 
 mechanical retention) until they afford favorable shape for the permanent 
 
 attachment of a band. (Fig. 103.) 
 
 Separate bands should be fitted to each, their 
 Bands. occlusal ends trimmed to allow for the cusp, and 
 
 contoured to approximate each other, and restore 
 contact with adjacent teeth. 
 
 nq.105. 
 
 The usual bite in wax. and impression in plaster should be secured, 
 and the case finally mounted upon the articulator. After separatmg, and 
 detaching the bands from the model in such manner as to preserve their 
 outline and admit of accurate replacement, they should be readjusted to 
 the model and united secureh' together with hard wax ; then they may 
 be removed and the ciTT'/ra/. one-half imbedded in investment material. 
 Their relation may now be permanently sustained by filling in between 
 
 Ficj. 
 
 106. 
 
 them With 22 karat solder, which union, involving the occlusal ends only, 
 will leave a free, clean interproximal space. (Fig. 104.) 
 
 The united bands may now be replaced upon the 
 
 Cusps. model and the cusps formed in the usual manner, as 
 
 though for the single band of an ordinary crown. 
 
 In attaching them, however, care must be exercised to prevent re-fusing 
 
 the solder with which the bands were previously luiited, and, thus cliang- 
 
ing or destroying the relation between them. The use of a lower grade 
 solder will ordinarily preclude this, but to further facilitate it the cusps 
 should be filled with solder after obtaining their proper adaptation, and 
 previous to attaching them to the bands. Very little danger will then 
 exist, and any may be entirely overcome by the use of a solution of 
 whiting and alcohol, which precaution it is well to observe. 
 
 Jipplication to Tndiv^idudl Roots. 
 
 Where but a single root remains or possesses sufficient strength, and 
 particularly in the lower jaw, it may often be retained and made service- 
 able for a number of years by the application of a crown. Also, in 
 instances where such a root may be unusually strong, and the space 
 formerly occupied by the normal tooth has become lessened or partially 
 closed as a result of the loss of the other root and the gra^•itation of the 
 adjacent teeth, it is often practical to extend the occlusal portion of the 
 crown until it rests against the adjacent tooth, and thus affords a con- 
 tinuous masticating surface. (Fig. 105.) The contact point between 
 such a crown and the natural tooth, however, should be only sufficient to 
 prevent tipping of the root from the stress of mastication, and for prophy- 
 lactic reasons should rest close to the occlusal surface and be smooth 
 and well rounded. 
 
 Cantilever Bridges. 
 
 A small intervening space between two artificial crowns may be 
 bridged over until an unbroken masticating surface presents, by applying 
 these same principles, as Avas originally suggested by Dr. J. N. Farrar. 
 (Fig. 106.) Such a procedure would be most practical, however, in cases 
 where a very small space existed, as one sufficiently large to accommodate 
 a dummy could usually be best filled by constructing an assembled bridge. 
 
 Jlpplicatioit of :Httial9atn. 
 
 Amalgam is sometimes employed in the restoration of badly broken 
 down molar roots by crowning, and, while good results in the line of expe- 
 ditious operations combined with a moderate degree of preservation and 
 permanency are probably possible, any method possessing only the advan- 
 tages of time and cost of production, and requiring less skill and effort 
 than a manifestly better and more artistic one, should very naturally 
 occupy the limited sphere of application and usefulness accorded to this. 
 
 In conditions and environments, however, which seem to indicate the 
 application of such methods, it is possible to obtain fairly good results in 
 the restoration of the crowns of second and third molars, where the occlu- 
 sion is very close^ by either of the following procedures : 
 
ii8 
 
 Where a permanent band may seem indicated as 
 
 mitb Band. a means of supporting the remaining- walls of the 
 
 root, and to aid in the retention of the amalgam, it 
 
 should be made of gold, carefully fitted and adapted, and then polished 
 
 and cemented to place. 
 
 Provisions should then be made for securely retaining the amalgam. 
 This may be accomplished either by means of a post, cemented into one 
 of the canals, or by cutting a mechanically retaining cavity if sufficient 
 tooth structure remains. 
 
 Very plastic amalgam should then be packed thoroughly to place, 
 and built up to the desired cusp formation, until a favorable occlusion is 
 obtained. 
 
 After crystallization, and preferably at a subsequent sitting, the 
 amalgam cusps should be well finished and polished ; and, while the gold 
 band will have assumed the same color by the superficial absorption of 
 mercury, its original color may be brought back by polishing, if desired. 
 
 If a permanent band is not desired, or seemingly 
 
 UlitbOUt Band. unnecessary, the entire crown may be made with the 
 amalgam. In this procedure a temporary band of 
 thin German silver, 32 to 34 gauge, should be made and adapted to the 
 root, as indicated. This is used only as a matrix for aid in adapting and 
 contouring the amalgam, and may be easily removed from the latter, after 
 its crystallization, by cutting, after which the amalgam crown may be 
 finished and polished. The easy removal of the band may be further 
 facilitated by coating its inner surface with vaseline or oil before inserting 
 the amalgam, which will prevent superficial amalgamation with it. 
 
 Where extensive destruction mav preclude sufficiently adequate reten- 
 tion for the amalgam, it may be first tightly packed to the surface of the 
 tooth and matrix, and around the projecting end of a aowel temporarily 
 adjusted to the canal if the use of the same seems indicated, 
 without any provisions for its retention. After crystallization 
 "both may be removed, the band separated, and the crown then 
 finished and polished, and finally mounted with cement, after serrating or 
 roughening the surfaces of crown and root. Such operations, however, 
 are of doubtful permanency as compared with those wherein a permanent 
 band is employed. 
 
 Jlpplicdtion t« tDe JInterior Cectb. 
 
 While it is difficult to conceive of a practice more flagrantly inartistic 
 than the application of gold crowns to anterior teeth or roots, as has been 
 previously observed, they are, nevertheless, occasionally employed. 
 
119 
 
 In view of the opportunities for more artistic endeavors, and the in- 
 creasing appreciation of and demand for the same, this class of gold crown 
 is now the exceptional expedient rather than the common practice. 
 and would douhtless soon hecome entirely (jhsolete were it not for a 
 iimitcd class of cases in which the requirements and environments seem to 
 justify such a procedure. 
 
 Their application in any event, including even these exceptional con- 
 ditions, should he made with an honesty of purpose, and a sense of profes- 
 sional duty, paramount to a mere catering to the perverted, unrefined 
 vanity of the vainglorious. 
 
 The class of cases in which their application is 
 
 Tn^ications. practicable and warrantable is confined to the mouths 
 
 of men past middle age, where they are partially or 
 entirely hidden by the beard. In such instances the use of gold crowns 
 may be indicated in tzvo general classes of cases : 
 
 First, where, from a more or less powerful masticating action, and by 
 
 f/cjf. J 07. 
 
 years of constant and continued attrition, the remaining teeth have become 
 so worn down as to require restoration with an absolutely indestructible 
 material. Second, in crowning the cuspid teeth, when they are to serve 
 as abutments for bridgework, and where it is desirable, and perhaps neces- 
 sary from a mechanical standpoint, to allow as much as possible of the 
 natural crown to remain in order to secure the additional strength thus 
 imparted to the attachment between crown and root ; and where the prac- 
 tical invisibility of the work may not reqtiire any special effort toward 
 securing the more artistic effects afforded by other means. 
 
 The first class of cases are not uncommon or infrequent, and usually 
 present a more or less perplexing problem. If an adequate number of 
 the posterior teeth remain, and occlude with teeth in the opposing jaw, a 
 more artistic result may often be obtained by crowning the posterior 
 teeth in such a manner as to open the bite sufficiently to accommodate 
 crowns having porcelain facings on the anterior teeth, with reasonable 
 
120 
 
 assurances of permanency and usefulness. But in the event of the loss or 
 absence of properly occluding posterior teeth, all, or the greater portion, 
 of the work of mastication may be thrown upon the remaining anterior 
 teeth, and thus preclude the use of porcelain and occasion the necessity 
 for gold, unless the posterior teeth be first supplied by artificial dentures. 
 
 Fig. 107 illustrates a case where the bite was opened by placing 
 crowns upon the posterior teeth, with cusps sufficiently thick to withstand 
 the work of mastication, and which thus admitted the application of porce- 
 lain-faced crowns to the anterior teeth. Fig. 108 illustrates a case where 
 the absence of the posterior teeth indicated the use of gold on the remain- 
 ing anterior teeth, and where the crowns were further fortified against 
 the stress of mastication by tipping each with 26 gauge clasp-metal. The 
 
 use of the clasp-metal is especially indicated where both upper and lower 
 teeth are crowned and the crowns occlude with one another. 
 
 In the application of these crowns, several 
 Proc^(3ure. methods are employed. The requirements of root 
 
 preparation, as have been outlined in general, include 
 securing the greatest diameter at the cervix by reducing the coronal pro- 
 portions, and further sacrificing the approximal, labial, lingual and incisal 
 surfaces until the remaining structure will admit of properly shaping and 
 contouring the crown, when the measurement should be taken as hereto- 
 fore indicated. A band of 28 or 29 gauge, 22 karat gold should then be 
 cut the exact length of the straightened measurement wire, and somewhat 
 zvidcr than the required length of the crown. 
 
 ■ As the correct adaptation can be most accurately 
 
 Adaptation to the obtained by fitting directly upon the root, and but 
 
 motltb« little time is thus consumed, the use of models is 
 
 unnecessary. ' 
 
 The band should be soldered, trimmed to meet the gum line evenly 
 
i2r 
 
 (Fig. 109, a.), and tlien forced to place n\)(ju the njot. \\ lien the cer- 
 vical adaptation has been completed, the lingual portion of the band 
 should l)e cut away, following the original curvature and outline of the 
 tooth. (Fig. 109, b.) The labial surface may now be contoured with 
 the pliers until it assumes i^n^iK-r sliai)C and alignment, and restores con- 
 tact with adjacent teeth, in which the artistic results possible are, of 
 course, in proportion to the degree of skill displayed. 
 
 The incisal end should now be trimmed to the proper length and 
 shape, with an allowance for the thickness of the lingual plate to be sub- 
 sequently attached, and of the clasp-metal also, should its use be desirable 
 or necessary. 
 
 A piece of gold. s<jmewhat larger tlian neces.sary, 28 to 30 gauge, 22 
 karat, should be adapted to the lingual portion of the band, held in 
 contact with pliers or wire, and soldered from the inside. fFig. 109, c.) 
 
 Fiq.lOQ. 
 
 Adequate re-enforcement of the incisal end should be obtained by 
 filling in sufficiently with solder, or by attaching a piece of clasp-metal, 
 previously cut to the exact size and shape, along the edge. 
 
 The surplus should be cut away, and the crown subjected to the acid 
 bath ; then finished and polished. 
 
 When it may become necessary, or seem desir- 
 
 Jldaptation able, to construct the crown upon models, thus con- 
 
 tfr models. fining the work to the laboratory, a narrow primary 
 
 band of copper or German silver, 32 gauge, should 
 
 be fitted to the root, and an impression, including the adjacent teeth, then 
 
 taken in plaster. 
 
 When this has been secured, the band should be adjusted accurately 
 to place, and the model obtained with fusible alloy, which is preferable to 
 plaster, being more indestructible. 
 
 With a sharp chisel or bur the outside surface of the band on the 
 model should be first freely exposed, when it may be cut in two and de- 
 tached. This will leave the adjacent teeth and the correct cervical outline 
 of the root definitely exposed in the model, and the crown can then be 
 constructed upon it in the manner inflicated, with reasonable accuracy. 
 
122 
 
 Those who may experience some difficulty in 
 
 (Carving and Swaging, shaping and contouring the labial surface with pliers 
 
 in an artistic manner, may be able to obtain better 
 
 results by carving and swaging both labial and lingual surfaces, though 
 
 this method seems unnecessarily circuitous. 
 
 To accomplish this the primary band should be fitted, the impression 
 taken, and a model secured in plaster. The band should be carefully 
 detached from the model and the latter varnished. With the band again 
 -adjusted to position, the intended crown may be formed with plaster, 
 which, after hardening, may be carved to the desired form. By the use of 
 :mouldine separate dies may now be secured of the labial and lingual sur- 
 iaces, with the line of junction at the center of the approximal and incisal 
 surfaces. (Fig. no, a.) 
 
 (' Each surface should be swaged separately ; the surplus trimmed 
 away ; the edges passed over a flat smooth file until they approximate 
 
 Ficj. I/O. 
 
 FiqJIL 
 
 evenly (Fig. no, b.), and the two finally soldered, with sufficient incisal 
 re-enforcement. 
 
 In this procedure the degree of accuracy obtained in the finished 
 crown will depend much upon first drawing or designatmg a definite line 
 between the two lateral halves of the plaster crown ; then securing an 
 imprint of each surface in the mouldine, having a vv^ell defined edge evenly 
 approximating this line, and finally trimming away the surplus gold, 
 after swaging, with care and precision before uniting the two with solder. 
 
 The accuracy and indestructibility of the metal model, however, sup- 
 plemented by the definite reproduction of the diameter and cervical out- 
 line of the root, which is afforded by the primary band, aids materially in 
 securing the desired result. 
 
 The various die-plate systems supplying a se- 
 Di^Plate methods, lection of dies of the labial and lingual surfaces may 
 often be employed to good advantage, with perhaps 
 increased artistic effect, and a reasonable degree of accuracy, though they 
 give a more typical reproduction of tooth-form than is usually necessary 
 -or required, except possibly for the cuspid teeth, as considered in the 
 second class of indications. 
 
123 
 
 The dies for this purpose contained in the Lowry 
 Cowry and ^"^1 AHllett systems include only the labial surfaces, 
 
 IHillCtt Systems. and may be used in accordance with their application 
 as formerly outlined. In their use the measurement 
 is taken and a band cut the proper length and width. The die is selected 
 which approximates the individual requirements of the 
 case, and the immediate center of the band is then con- 
 formed by swaging; after which it is trimmed, as indi- 
 cated in Fig. Ill, made in circular form and soldered. It 
 is now fitted and adapted to the root, trimmed to assume 
 the proper lingual curvature, and to admit of the attach- 
 ment of the lingual plate, as previously shown in Fig. 109. 
 
 The Hollingsworth and Baird 
 I^OllindSWOrtb and systems include separate dies of both 
 BaIrd Systems. the labial and Ungual surfaces 
 mounted on a single base, and may 
 be used in similar manner, in accordance with their ap- 
 plication, as previously outlined. 
 
 When the die which most closely approaches the 
 requirements for side, size and form has- been selected, 
 the gold should be swaged, and both sides of the crown 
 then trimmed until properly approximated. They should 
 then be wired together, fluxed, and soldered from the in- 
 side. (Fig. 112.) While it may now be possible to so trim and shape the 
 cervical end as to secure a fairly good adaptation to the root, a more ac- 
 curate result may be obtained by adapting a narrow band of gold to the 
 root and then fitting the crown oz'er it, and subsequently attaching them 
 with solder, when the incisal end may be adequately re-enforced and the 
 crown finished and polished. 
 
 The application of the seamless method to the 
 Seamless method, restoration of anterior roots is identical in detail to 
 the procedure previously indicated in tlie construction 
 of bicuspid and molar crowns. As the lingual outline of the adjacent 
 teeth, however, will often serve as a guide, the taking of a "bite" becomes 
 necessary only when the opposing teeth may be irregular, or where an 
 incisal or "end to end" occlusion is required. 
 
 The primary band should be made and fitted in the manner outlined, 
 and the impression secured in plaster. When the model has been obtained, 
 _ the crown should be formed and carved, and the dies made in accordance 
 with, and the swaging accomplished by, the process selected. 
 
 Seamless crowns are also especially useful for bicuspids where porce- 
 lain facings are to be attached. 
 
124 
 
 In applying this method to the construction of 
 Reproductions. cuspid crowns where the entire natural crown re- 
 mains, accurate reproductions of the tooth may be 
 quite easily made. To accomplish this, the natural crown must first be 
 trimmed sufficiently on the approximal sides to admit of an accurate ad- 
 justment of a band to the cervix, and, if necessary, upon the incisal, labial 
 and lingual surfaces, to admit of securing the proper length, alignment 
 and occlusion. A narrozv primary band should then be fitted to the neck 
 of the tooth, and the impression and subsequently the model secured in 
 plaster. The plaster tooth should now be cut from the model in the man- 
 ner indicated in Fig. 91, and the dies or swaging model secured as the 
 selection of processes may require. When the swaging has been com- 
 pleted, the crown will be a close reproduction of the tooth and will fit it 
 accurately. Sufficient incisal re-enforcement to prevent wearing through,, 
 however, must always be made, even at the expense of grinding the nat- 
 ural crown, if necessary. 
 
 This procedure is sometimes employed without using the primary 
 band, but is, of course, less accurate, as the band indicates the proper rela- 
 tion to the root under and within the free margin of the gum, which other- 
 wise can only be approximated by trimming the model at this point. 
 
 In those cases where the natural crowns are sa 
 Dowels. badly worn or broken down as to afford inadequate 
 
 attachment for the crown, the use of a dowel may 
 become necessary as a means of supplementing the telescope attachment, 
 and thus offering increased integrity. Their application may be made by 
 first fitting them to the canal, and then allowing a projecting end to extend 
 into the crown as far as its incisal edge will admit. After thus ascer- 
 taining the proper length, the dowel should be previously cemented to 
 place in the root, and the crown subsequently attached. 
 
 Jlpplication to Deciduous CeetD. 
 
 In some fortunately rare and exceptional instances, where the ex- 
 tremely poor character of the deciduous teeth precludes their temporary 
 preservation by other means, and demands the employment of some heroic, 
 or, perhaps, radical procedure to prevent their premature loss, the appli- 
 cation of gold crowns may be indicated as the most simple, expedient and 
 available means of preserving them until the time for the eruption of their 
 permanent successors. 
 
 In such cases little or no preparation would of course be possible, or 
 necessary, and good results may often be accomplished by covering the 
 little crowns of such teeth with caps made of pure gold. 
 
T25 
 
 In the procedure a wire measurement of the cervical circumference 
 should be taken, and then an impression in z^'a.v, from which a plaster 
 model may be secured, which will afford sufficient accuracy for the 
 purpose. 
 
 Pure gold about 34 gauge should be then cut the length of the meas- 
 urement, made in circular form and soldered, and then fitted and shaped as 
 accurately as possible on the model. 
 
 It should then be finally soldered, with but little reinforcement, and 
 finished and polished. 
 
 The tooth should then be thoroughly disinfected, and the crown 
 mounted with cement, and carefully burnished to a close adaptation w'ith 
 the neck of the tooth. 
 
 By this means this class of teeth ma}' be saved until the proper time 
 for their loss with the utmost expedience, and without unduly taxing the 
 patients of such tender years. 
 
 Ready-made Terms. 
 
 As a woful acknowledgment and conclusive evidence of the lack of 
 skill possessed by some, and of the ever-ready willingness of the supply- 
 houses and commercial dentists to cater to and supply the demand, a large 
 variety of ready-made seamless crowns, in gold and aluminum, are pro- 
 curable ad libitum. 
 
 They are made of moderately topical form, in a gradation of sizes, of 
 22 karat, 30 gauge gold, and about 26 or 28 gauge aluminum, and in their 
 use a measurement of the root is taken and a crown selected which ap- 
 proximates the same diameter. The cervix is then trimmed until a closure 
 of the occluding teeth, with it in position, is possible, wdien it is fitted to 
 the root with pliers, and, if of gold, re-enforced with solder and mounted. 
 
 The most accurate method of fitting a ready-made gold crown to a 
 root is to cut a slit in each approximal surface, lap the edges, place the 
 crown on the natural root and contract its cervical circumference by en- 
 circling the crov/n with annealed German-silver or copper wire and twdst- 
 ing the wire till the band is in good contact with the root. Adaptation is 
 further perfected by burnishing, after which the slits are united with 
 solder. 
 
 That such crowns may be correctly adapted to all the requirements 
 of all environments is doubtless a claim which no conscientious skil- 
 ful operator would make, because, while their individual formation is 
 fairly typical of the natural teeth, it is difficult to conceive of securing a 
 ready-made form which can be adapted to the requirements of cervical 
 adaptation, approximal restoration, occlusion and alignment, all combined. 
 Indeed, these requirements are often difficult to obtain in a crown 
 
[26 
 
 which is made for the individual case, and at the expense of every degree 
 of energy, skill and handicraft possessed by, and at the command of, the 
 operator. 
 
 The progress of dentistry, and the artistic possibilities pertaining to 
 it, have only been achieved by the development of a superior skill which 
 cannot be acquired by the adoption of such indifferent methods. 
 
 Rcmovittd and Repairiitd* 
 
 As a result of pathological disturbances arising beneath them, or 
 for the purpose of substitution or replacement, it not infrequently becomes 
 necessary to remove a gold crown from its attachment to the root. 
 
 In the presence of conditions demanding therapeutic treatment, it is 
 sometimes possible to cut through the occlusal surface of the crown on a 
 line with the pulp chamber, with a sharp, spear-point drill or round bur, 
 and then enlarge the opening until adequate access to the canals is se- 
 cured. The necessary treatment may then be made through this opening. 
 
 Ficj, 113, 
 
 upon the completion of which the pulp chamber and crown may be filled 
 with cement, and a gold filling, anchored in the cement, subsequently m- 
 serted until the opening is imperviously closed. 
 
 While such a procedure may be productive of successful results in 
 £ome instances, particularly in bicuspids or single-rooted teeth, it should 
 not be regarded as a saje one in most cases, because the presence of the 
 crown only adds to the difficulties to be encountered in an operation which 
 is usually trying enough under the most favorable circumstances, and with 
 every advantage of access and light. 
 
 For this reason the removal of the crown is almost invariably indi- 
 cated as a means of affording greater convenience and increased oppor- 
 tunities for success, and may be easily accomplished in two ways. 
 
 Where it is not necessary to preserve the con- 
 0roWtt Slitting tinuity of the band for subsequent replacement of 
 forceps. the crown, and in emergency cases where its imme- 
 
 diate removal is indicated or demanded as a means of 
 affording relief, the crown slitting forceps may be used to good advan- 
 
127 
 
 tage. Those designed by the S. S. White and the Consohdated Dental 
 Manufacturing Companies, the appHcation of which latter is shown in 
 Fig. 113, are especially useful in securing the easy and expeditious de- 
 tachment of the crown from the root. 
 
 In their use the flat beak should rest firmly upon the crown, and the 
 sharpened one caught just under the edge of the band, when a slight 
 compression of the handles will quickly separate it. The band may then 
 be pried away from the root with a smooth flat burnisher until a pointed 
 instrument can be slipped in between cusp and root and the crown lifted 
 off, which may also be often done with the forceps alone. 
 
 When the same crown is to be replaced, it may 
 
 Preserving be desirable to remove it without destroying the con- 
 
 Gontinuity ©f Band, tinuity and shape of the band, thus distorting 
 
 its adaptation. This may be easily accomplished by 
 
 drilling through it with a round bur at a convenient point, as close to the 
 
 occlusal surface as the probable thickness of the cusp will admit (Fig. 
 
 Ficf.ll4. 
 
 114), and then burring out as much of the cement between cusp and root 
 as possible by a lateral movement of the bur. A stiff, blunt-pointed in- 
 strument, similar to an old hand-plugger, should now be inserted into 
 the' opening, until its end rests about on the center of the root, thus secur- 
 ing a leverage by the establishment of a fulcrum, when the crown may be 
 lifted off with but little effort. 
 
 While a crown removed with the slitting forceps 
 Repairing may be easily repaired, as no material is destroyed, 
 
 it is doubtful if the edges so cut can be again brought 
 into proper relation and contact without requiring a readaptation to the 
 root in case of replacement. Aside from this, the two procedures may be 
 interchangeable and can be used as convenience and requirements may 
 seem to indicate. 
 
 In either event, when repair is necessary, all remaining cement should 
 be first removed with a bur, and the crown then thoroughly cleaned in 
 acid, when the perforations may be filled with foil gold, and, together 
 with other openings, then finally closed with 18 karat solder. 
 
tbc Sbell or telescope grovpn in Combination witb Porcelain. 
 
 VIII. 
 
 Indications. Application to Anterior Teeth : Jacket Crowns ; Malformed Teeth, 
 Extensive Abrasion, Procedure; Band, Facing, Backing, Soldering. Appli- 
 cation to Irregularities. Application of Facings to Bicuspid Crowns : 
 Procedure; Preparing Crown for Reception of Porcelain, 
 Adapting Facing, Adapting Backing, Soldering Backing, 
 Soldering Facing. Variation of Method. Applica- 
 tion of Saddle-back Teeth to Bicuspid and 
 Molar Crowns: Procedure. Dowels. 
 
 The application of porcelain facings to crown construction, wherein 
 the shell or telescope principle of attachment to root is employed, involves 
 several varied methods and processes, many of which are often indicated 
 in special classes of cases, and may be productive of practical and artistic 
 results. 
 
 While the modern application of the ceramic art doubtless offers far 
 greater opportunities for more aesthetic and hygienic achievements in this 
 line of work, the essential requirements of strength as applied to the 
 method of attachment to the root, as well as to the completed crown, are 
 factors not infrequently contraindicating its use. These, together with the 
 absence of facilities, or the lack of experience and skill, may often indicate 
 the combination of gold and porcelain as a means of obtaining increased 
 strength, and of securing, or more closely approaching, the desired artistic 
 and aesthetic result. 
 
 The application of this style of crown construc- 
 Tndications. tion is especially indicated in that class of cases where 
 
 it seems desirable, or becomes necessary to utilize a 
 portion of the remaining natural crown for the attachment of the artificial 
 substitute, by telescoping it instead of sacrificing it to the gum line and 
 employing a dowel ; and where the presentation of porcelain is essential 
 to the artistic requirements. 
 
 Those conditions in which these combined requirements are par- 
 ticularly applicable, and the preferable and most practical methods of 
 subserving them, will be considered in their respective classification. 
 
129 
 
 jRpplicdtiott to jFInterior Ceetb. 
 
 The application of this style of crown to the six anterior teeth, upper 
 or lower, is frequently indicated, but should be made only in the absence 
 of a better method, and in accordance with the judgment and discretion 
 of experience, because the practicability of the principles involved has been 
 much abused by the indiscriminate and too extensive use of the design 
 known as the jacket crown. 
 
 The so-called jacket crown is often a most use- 
 33Ck(t €rown$. ful style of construction, but is particularly so in the 
 restoration of malformed crowns of teeth, as pre- 
 viously indicated in Fig. 29, and in conditions of extensive abrasion. 
 As the proportions of the remaining natural crown, however, are ordi- 
 narily retained at the expense of the strength of the artificial substitute, 
 because of the limited amount of space, the requirements of occlusion and 
 alignment must be, or be made, favorable to the reception of a crown 
 possessing sufficient strength to withstand the stress. For this reason 
 the use of gold in combination with porcelain facings usually affords 
 greater strength than all-porcelain work. 
 
 In the restoration of the crowns of malformed 
 malformed Cceth. teeth the use of the jacket crown is particularly ap- 
 plicable because of the usual favorable shape and 
 formation of the natural crown ; and for the reason that it is often de- 
 sirable to preserve the vitality of the pulp in such teeth, because of the 
 probable unfavorable length and imperfect development of the root, which 
 might often preclude securing adequate mechanical attachment of a dowel 
 ■crown. 
 
 In such conditions the destruction of the natural crown would, of 
 course, be of doubtful advantage, and sometimes even unwarrantable ; and 
 the preservation of the vitality of the pulp presents a favorable prognosis 
 because usually so little mechanical preparation would become necessary 
 that no great shock or irritation would be induced, and the dentine is 
 not deprived of the protection of its coat of enamel. 
 
 This style of crown is also frequently indicated 
 €xtCn$iV( Jlbrasi^n. as a means of arresting the destructive influences of 
 abrasion, and restoring the natural crown in a useful 
 and aesthetic manner. If the occlusion in such cases is, or may be made, 
 favorable for, and the requirements indicate the use of, porcelain facings, 
 the preservation of the remaining natural crown may afford the advantage 
 of a more accurate and perfect reproduction of the occlusal surfaces, and 
 at the same time adequate stability to the attachment of the crown. 
 
 The advisability of destroying the vitality of the pulp in these cases 
 is much a matter of judgment, but is not always essentially a prophylactic 
 
I30 
 
 measure, because such conditions are not usually found in early life- 
 Hence, as a result of the combined influences of age and continued at- 
 trition, the pulps have usually receded, and the canals are not infrequentljr 
 found to be partially or entirely obliterated. The degree of s'ensitiveness 
 manifested during the necessary mechanical preparation will serve as a 
 guide, however, in indicating the requirements in this connection. 
 
 The first procedure constitutes the preparation 
 Procedure. of the remaining natural crown until its periphery 
 
 presents a favorable shape for the accurate adapta- 
 tion of a band, and the labial, lingual and incisal surfaces are sufficiently 
 reduced to afford accommodation for a facing, and admit of a favorable- 
 occlusion. (Fig. 115, a.) 
 
 A band of about 30-gauge 22-karat gold should 
 Band, then be fitted to the root, passing just freely beneath 
 
 the gum. After completing the adaptation of the cer- 
 vical end, the labial portion should be cut away on a gradual slope, closely 
 following this surface of the remaining crown, until the facing may be car- 
 ried to the gum line. The lingual portion of the occlusal end should then 
 be trimmed until it ofifers no interference to the occlusion, after which the 
 interior of the band, in position on the root, should be filled even to its 
 edge with wax, and the bite and impression secured. 
 
 When the model has been obtained and mounted 
 Tacing. upon the articulator, a facing of the thin neck va- 
 
 riety of mould (Fig. 115, b.) should be selected and 
 ground to place, with a slight allowance for the thickness of the backing. 
 
 Pure gold, 34 to 36-gauge, should be closely 
 B(ICbin9. adapted to the entire lingual surface of the facing, 
 
 so as to join or come in direct contact with the band 
 along its labial and cervical edge when adjusted to position (Fig. 115, c). 
 When the backing has been properly burnished and trimmed, and anchored 
 to the facing by bending the pins, the band should be detached from the 
 model, then replaced in position and the proper relation between it and 
 the facing sustained with adhesive wax. The joint between the band and- 
 
'3' 
 
 backing should also be filled with melted wax as a means of keeping it 
 clean and facilitating the subsequent union of the two with solder. 
 
 \\'hen invested, the wax should be removed and 
 
 Soldering. a small cap of 22-karat or pure gold closely fitted to 
 
 the interior edge of the band. The case should now 
 
 be fluxed, heated and soldered, with as much re-enforcement and contour 
 
 as the occlusion will permit. (Fig. 115, d.) 
 
 In cases where a broad, flat contact surface for the opposing teeth 
 may be required, successive layers of clasp metal may be attached with 
 solder until a favorable occlusion is secured. In this event the incisal 
 end of the thin pure gold backing must be also adequately re-enforced 
 wath solder, though a better method of backing for such cases will be 
 subsequently considered. 
 
 It will be noted that the adaptation of the crown to the projecting 
 conical end of the natural tooth is not close, but a closer conformation is 
 usually unnecessary if the cervical edge fits, as the increased quantity of 
 cement thus used in mounting adds materially to the strength of the 
 attachment. 
 
 If, for any reason, a more perfect adaptation may seem indicated, or 
 desirable, it may be easily secured by burnishing or swaging a cone of 
 pure gold, 34 to 36 gauge, or platinum foil, i-iooo in thickness, to the 
 tooth in the mouth, after the band has been fitted and trimmed ; then 
 adjusting first the cone and then the band to position, removing them 
 ill situ, with their relation sustained wdth wax, and investing and solder- 
 ing them, when the crow^n may be completed as indicated. 
 
 Such a procedure is seldom required or even warrantable, how-ever, 
 because so little cement could be used in mounting that a more or less 
 weak attachment would necessarily result. While the simple telescoping" 
 cone is sometimes used without the band, the latter is essentially advan- 
 tageous as a means of securing sufficient strength at the cervical end 
 and adequate adaptation to the root beneath the gum. 
 
 When the crown has been finished and polished, the remaining natu- 
 ral tooth should be roughened or slightly serrated with a thin edge stone, 
 or sharp bur, before mounting, as such a procedure ofifers a mechanical 
 supplement to the adhesive properties of the cement, which affords in- 
 creased strength in the attachment. 
 
 Jlpplicatiott to Trregularities. 
 
 The jacket crown may also be found occasionally useful in the treat- 
 ment of irregularities, where the character and position of the teeth, and 
 the age of the patient, may not warrant the usual procedure for their cor- 
 rection. 
 
132 
 
 The method advocated by Dr. George Evans is illustrated in Fig. 
 1 16, and consists of constructing a gold crown for the malposed tooth, 
 and then attaching a facing to it by means of a heavy round wire, so 
 adjusted as to carry the facing in its proper relation to the adjacent teeth, 
 and to be free of the occlusion. 
 
 The more or less conspicuous appearance of the gold crown, even 
 
 Fic].ll6. 
 
 though partially hidden by the facing, is an objectionable feature, how- 
 ever, and equally useful and more artistic results could be usually ob- 
 tained by sacrificing the natural crown and adapting a dowel crown to 
 support the facing in its proper position. 
 
 Jlpplication of Taciiids to Bicuspid €rown$. 
 
 As a means of eliminating the objectionable and conspicuous display 
 of gold in crowning the bicuspid^, the application of porcelain facings to 
 gold crowns is frequently indicated, and, if skilfully executed, approaches 
 the more artistic results achieved in the use of porcelain work, or dowel 
 crowns. 
 
 While various methods are advocated and employed, a slight modi- 
 fication of the one suggested by Dr. Hollingsworth meets the requirements 
 in the most practical, artistic and expeditious manner. 
 
 In the procedure the gold crown should be first 
 
 Procedure. constructed by any of the various methods in which 
 
 the swaged cusp is used, but the band and cusps 
 
 should be soldered with 22-karat solder, and no re-enforcement of the 
 
 cusp made at the time of uniting it to the band. 
 
 When thus completed, and roughly finished, the root should receive 
 further and proper preparation for the accommodation of the porcelain 
 facing. This constitutes sacrificing the buccal surface on a gradual slope 
 to the lingual, at an angle sufficient to admit of the presence of the facing 
 when placed in position on the crown, as previously illustrated in Fig. 40. 
 
133 
 
 The crown should now be adjusted to the root 
 
 Preparing Crown and the outline of the exposed area, to be occupied 
 
 for Reception by the facing, marked in the gold with a sharp-pointed 
 
 Of Porcelain. instrument, and subsequently cut out with a fine saw, 
 
 as indicated in Fig. 117, a. 
 After filing the edge smooth and even, with the convex surface of 
 a fine half-round gold file, a thin cuspid facing of proper size and color 
 should be selected and ground to place. 
 
 F/a.//7. 
 
 While the grinding may be done on models, 
 Hdapting facing. when necessity or occasion requires, the most accu- 
 rate results can be accomplished by filling the in- 
 terior with wax, when in position on the root, and completing the adapta- 
 tion in the mouth. In grinding to the necessary alignment, and approxi- 
 mation with the edge of band, care should be exercised to avoid sharp 
 angles and an}^ unnecessary weakening of the pins. 
 
 When the desired adaptation has been completed, 
 Hdapting Backing, a sufficient allowance for the thickness of the backing 
 should be made by further grinding the facing or 
 the band, or both ; and the facing then backed up with pure gold, about 
 34 gauge. In the adaptation of the backing a small surplus should be 
 allowed to project beyond the facing at all points (Fig. 117, b), and care 
 must be exercised to avoid overlapping it, to accomplish which it may 
 sometimes be necessary to cut out a small V-shaped piece at each occlusal 
 angle. 
 
 The facing and backing should now be placed in 
 Soldering Backing, position on the crown, and a sharp instrument passed 
 around the buccal edge of the crown, marking the 
 proper relation between it and the backing (Fig. 117, c), after which it 
 should be detached, and the backing soldered to the crown from the 
 outside with 20-karat solder, using enough to form a smooth joint, which 
 may finish down flush with the porcelain when the surplus is removed ; 
 
T34 
 
 and the necessary re-inforcement of the cusps should be made at this 
 time. 
 
 The proper relation between the parts may be most easily and securely 
 
 Fiq.llB. 
 
 sustained while soldering- by the use of pliers similar 
 'in design to those previously recommended for attach- 
 ing cusps, or the ordinary nickel automatic soldering 
 tweezers may be used by bending one end at right angles, 
 as indicated in Fig. ii8. 
 
 When the soldering has been completed, the fac- 
 ing should be adjusted to position and the surplus 
 trimmed down until a smooth edge presents between 
 crown and facing, being careful to az'oid any over- 
 hanging edges of metal upon porcelain. 
 
 While the permanent reten- 
 SOldcring Tacins. tion of the facing may be secured 
 by bending the pins down against 
 the backing, on the inside of the crown, greater 
 strength will be obtained by soldering, on account of 
 the extreme thinness of the backing. This may be 
 quite easily accomplished by first bending the pins 
 down close upon the backing, and then wrapping the 
 crown with one thickness of asbestos paper, with the 
 occlusal end folded together, and the whole held in place by wiring. 
 The backing and pins should then be fluxed, preferably with liquid flux, 
 and a sufficient quantity of i8-karat solder also fluxed, and placed in 
 position. This should now be carried to the flame, with the porcelain 
 downward, and gradually brought to the point of greatest heat (Fig. 
 119), when a small flame from the blow-pipe may be directed upon 
 the facing until the solder fuses, which can be readily observed from the 
 open cervical end. 
 
 While this or any other style of investment is not altogether neces- 
 sary, if extreme care be exercised in subjecting the crown to the heat, the 
 
 Fiq.119. 
 
^35 
 
 use of asbestos paper possesses the advantage of absorbing but little, if 
 -any, heat, and of precluding the possibility of fracturing the facing, bv 
 ■distributing it evenly. 
 
 When the soldering has been completed, the crown should be treated 
 to the acid bath, and then finally polished (Fig. 117, d), and mounted. 
 
 If an undue prominence of the root interferes with its proper adjust- 
 ment, it may become necessary to sacrifice more from the buccal surface, 
 but the lingual surface should alvva}s be allowed to remain as long as 
 possible, in order to afford the greatest degree of strength to the at- 
 tachment. 
 
 Another process or method productive of prac- 
 Uariation Of method, tically the same results, but entailing a different pro- 
 cedure, is employed by many. This constitutes first 
 making the band, and fitting it to the root, and then cutting out the buccal 
 surface to accommodate the facing as indicated in Fig. 120, a. 
 
 F/C7./20. 
 
 The usual bite and impression should now be taken and the models 
 secured and mounted upon the articulator. A cuspid facing of suitable 
 size and color is then ground to place until the proper alignment, and a 
 perfect joint with the cervical and approximal edges of the band, are 
 secured. After backing the facing with 30-gauge 22-karat gold, and 
 bending the pins (Fig. 129, b), the band should be detached from the 
 model, the facing placed in position upon it, and their relation sustained 
 with a nnniite quantity of fluxed wax. Asbestos paper should now be 
 wrapped around the parts and w'^-ed, as indicated, and the joint between 
 the two filled with 20-karat solder (Fig. 120, c). 
 
 This portion of the crown should now be readjusted to the models, 
 and the cusps formed to fit the band and facing, and meet the require- 
 ments of occlusion, after which they should be filled with i8-karat solder. 
 
 In attaching the cusps to the band and facing they should be first 
 Tetaiued in proper relation by the use of a small quantity of fluxed wax. 
 Asbestos paper should now be wrapped around the crown with the oc- 
 clusal end knuckled in close to the cusps, and then wired securely to place 
 
136 
 
 by twisting- the wire very taut around the approximal, occlusal and cer- 
 vical surfaces, to sustain the relation of the cusps, as well as having an • 
 additional piece of wire pass around the center of the crown to hold the 
 paper together. 
 
 With the surplus ends of the wire projecting from the cervical end 
 of the crown, it may be carried to the flame, cusps dozvnward, and so held 
 until the solder, already in the cusps, has re-fused and united with 
 the band. 
 
 If insufficient solder has been placed in the cusps to accomplish union 
 in such manner, more may be added at this time, and, as in the previously 
 mentioned method, if any danger of re-fusing or unsoldering joints, 
 already made, seems probable, the same can be overcome and prevented 
 by first coating them with a solution of whiting in alcohol or water, or 
 other similar means. 
 
 After soldering, the crown should be allow^ed to cool slowly and 
 gradually, and then may be removed from the investment, finished and 
 polished (Fig. 120, d). 
 
 While such crowns may be invested in ordinary investment material, 
 the soldering can be accomplished with equal facility and accuracy, and 
 much more easily, in this manner. 
 
 Jlpplication of Saadlc-back Cectb to BiCHspia and molar €rown$. 
 
 The application of the saddle-back tooth to the construction of bi- 
 cuspid and molar crowns is sometimes practicable as a means of admitting 
 of the shell or telescope principle of attachment, and of affording an ar- 
 tistic and aesthetic result, because of presenting an occlusal surface of 
 porcelain. 
 
 The element of strength possessed by such a crown, however, depends 
 much upon the extent of space, and the force of the masticating stress,. 
 in the individual case, as the Ungual cusps are weak points, unless suf- 
 ficient space exists so as to require but little, if any, grinding, and adequate 
 opportunity is offered for protecting and supporting them. 
 
 In the procedure incident to the construction of 
 PfCCCdur^, such a crown, the band should be made and fitted 
 
 in the same manner pursued for an all gold crown, 
 and the bite and impression then taken. 
 
 The root should be afterward trimmed to accommodate the presence 
 of the porcelain. 
 
 When the models are mounted upon the articulator, a saddle-back 
 tooth (Fig. 121, A), the occlusal surface of which approximates the size 
 and proportions of the band, should be selected. In no instance should 
 the porcelain be much smaller than the diameter of the band, but in the; 
 
^i7 
 
 event of its being too large it may, of course, be ground to proper pro- 
 portions. 
 
 The band should now be detached from the model and cut away with 
 curved-pointed shears to admit of the proper adjustment of the porcelain 
 (Fig. 121, b). 
 
 The porcelain should then be carefully ground until it meets the re- 
 quirements of alignment and occlusion, comes in contact with the remain- 
 ing cervical edge of the band, and fits into the interior of the lingual and 
 occlusal portion. 
 
 It should now be backed up with pure gold, about 34 gauge, securelv 
 attached by bending the pins (Fig. 121, c), and then placed in position 
 on the band, and the proper relation sustained with melted wax. 
 
 After filling the interior with soft wax to keep it clean, the crown 
 should then be invested by submerging it in a slight coverino- of invest- 
 ment material, leaving only the wax exposed. 
 
 Upon removing the wax the interior of the crown will be exposed, 
 when flux can be applied and sufficient solder placed over the pins and 
 around the joint. The case should then be gradually heated to a red 
 heat, when a small flame from the blow-pipe, directed into the crown, will 
 quickly accomplish the soldering. 
 
 When removed from the investment and subjected to the acid bath, 
 the band should be burnished up closely to the porcelain, and the crown 
 finished and polished (Fig. 121, d). 
 
 In the application of crowns constructed by these 
 DomI$. latter methods, the shortness of the root may some- 
 
 times indicate the use of a dowel as a means of 
 supplementing the band and affording a stronger attachment to the root. 
 When this is required, or seems desirable, it should be first fitted to the 
 canal and a projecting end extended into the lingual portion of the crown 
 as far as its proper adjustment will admit. The dowel should then be 
 cemented to place in the root, and the crown separately and subsequently- 
 mounted. 
 
tbe Band and Dowel grown. 
 
 CHAPTER IX. 
 
 Indications. Requirements: Mechanical, Esthetic; Cervical Curvature, Alignment, 
 Color and Harmony, Oil Colors, Manufacturers' Products. Dental Labora- 
 tories. Method of Construction : Procedure ; Bands, Soldering, Fitting. Form- 
 ing Cap. Dovv^els. Bite. Impression. Adaptation of Facing; Cervical End, 
 Incisal or Occlusal End. Backing of Facing ; Adaptation. Re-enforcement. 
 Soldering, Finislung. Variation in Method. Use of Platinum. Investing. 
 Soldering. Finishing. Application of Partial Bands : Comparative Advantages. 
 Indications, Procedure. Application of Riveted Facings : Procedure, Riveting. 
 Application of Detachable and Replaceable Facings: Advantages Claimed, Ad- 
 vantages Considered, Advantages Obtainable, Various Designs; Mason's Facing; 
 Application. Roach's Facing; Application. Dwight's Facing ; Application. Bry- 
 ant's Method : Applicttion ; Box Method, Tube Method. Davis Crown. Applica- 
 tion to Bicuspids and Molars: Indications; Bicuspids, Molars. Procedure; 
 Re-enforced Cap, Use of Tvi^o Dowels, Bite and Impression. Use of Flatback 
 Facing, Facing, Cusps, Adaptation, Approximal Restoration, Investing, Solder- 
 ing. Use of Saddle-Back Teeth : Procedure. Use of Vulcanite Teeth. Ap- 
 plication of Removable Crowns. Application to Irregularities: Indications; 
 Malposition, Construction, Extension for Support of Facing, Hygienic Con- 
 siderations. Diminution of Normal Space ; Separation of Teeth ; Application 
 of the Intradental Band : William's Method, Application ; Cigrand's Method, 
 Application. Repairing : Replacement of Facings ; Usual Method, Procedure. 
 Brewer's Method; Application. Underwood's and Mitchell's Method; Applica- 
 tion. Dwight's Method; Application. Bryant's Method; Application. Replac- 
 ing Bicuspid and Molar Facings. Replacement of Facing and Backing; Proce- 
 dure. Removing: Use of Excising Forceps, Separating Cap and Dowel; Ac- 
 curacy in Model Making, Improved Articulators. 
 
 The usefulness and seviceability of the band and dowel crown in the 
 various phases of its present application and construction account for its 
 extensive employment, and warrant giving special emphasis to the detail 
 of the respective methods advocated. 
 
 While the primitive application of a band as applied particularly to 
 the construction of anterior crowns, and combined with a dowel and porce- 
 lain tooth or facing, was probably first suggested by Dr. C. 
 M. Richmond, the present methods of construction, and the facil- 
 
139 
 
 ities for accomplishing the requirements, have so modified the original 
 design as to cause its complete abandonment, and the adoption of a proce- 
 dure more practical, artistic and expeditious. 
 
 As there have been innumerable processes proposed, onl\- the more 
 jn-acticable of those now in use will receive attention. 
 
 Tndications. 
 
 Because of the necessary use of porcelain for esthetic reasons, and 
 of the additional strength and stability in the attachment afforded by the 
 presence of a band, together with the hermetical sealing of the root and 
 the safeguard against fracture, this style of construction is indicated in, 
 and universally applicable to, the restoration of the ten anterior teeth, 
 and not infrequently the first molars. Within the sphere of its applica- 
 tion it occupies the same degree of general utility, and offers the same 
 assurances of favorable permanency as does the gold crown in the 
 restoration of posterior teeth. 
 
 As the application is confined to the range of vision, the requirements 
 in connection with the construction of such crowns may be properly classi- 
 fied as mechanical and esthetic, and yet in all efforts calculated to be pro- 
 ductive of a high degree of permanency and artistic endeavor the two 
 cannot well be disassociated. 
 
 Whilst it is now generally conceded that the 
 
 mechanical. addition of a band to dowel crowns affords the pre- 
 
 viously mentioned advantages, it is also readily 
 acknowledged that the mechanical adaptation, or relation, of the same to 
 the end of the root must be uniformly deep, and close enough to the per- 
 iphery to preserve the continuity of surface between root and crown at 
 the line of junction beneath and within the free margin of the gum, so 
 that no irritating influence may result. At the same time, it is almost 
 equally essential that the band should be sufficiently narrow to 
 be entirely invisible, and thus admit of bringing the porcelain into close 
 proximity with the gingival margin ; and yet strong enough to retain its 
 given shape and form during the process of fitting and adapting, and 
 when subsequently subjected to the stress of mastication. 
 
 The importance of properly trimming the end of the root to begin 
 with, has already been sufficiently emphasized, and is particularly appar- 
 ent in the shaping of anterior roots, because of their even more conical 
 shape. If this is neglected in the slightest degree, the cervical edge of 
 the band must form a shoulder between it and the surface of the root, 
 which, though hidden by the gum, affords opportunity for the lodgment 
 
140 
 
 and accumulation of food deposits, the subsequent decomposition of which 
 is productive of a decidedly unhygienic condition, and much consequent 
 discomfort. While nature may aid the indifferent, careless or negligent 
 operator for a time, by covering over the evidences of such efforts — and 
 in this connection the tissues surrounding roots supporting artificial 
 crowns cover a multitude of sins — the result is inevitable ; hence, no band 
 at all were better than one zvhich does not fit. 
 
 In the esthetic restoration of the crowns of ante- 
 €$thCtiC$. rior teeth, success, with all it implies, is codependent 
 
 upon the ability to observe the minutest details in an 
 endeavor to simulate nature, and that degree of enthusiasm and ambition 
 which prompts a thorough and efficient execution of the artistic require- 
 ments involved. 
 
 These embrace a consideration of the details of Cervical Curvature, 
 Alignment, Color and Harmony. 
 
 In order that the natural cervical curvature of 
 
 Cervical Curoature. the gum tissue should remain normal, and that no 
 
 metal should be visible in the finished crown, it is 
 
 essential that its adaptation should be made with this requirement in view. 
 
 Ficj.122. 
 
 A common fault of this kind, the disregard of which materially in- 
 creases the artificial appearance of the work, as compared with the correct 
 and artistic outline, is illustrated in Fig. 122. 
 
 The feature of alignment with adjacent teeth is 
 Jllisnmcnt. most important, and particularly as applied to the 
 
 cervical half of the crown. A common fault with 
 many crowns, otherwise artistic, is an undue prominence at the neck,, 
 which is caused by not cutting the labial portion of the root short enough, 
 or by the selection of a facing too thick or bulbous at this point, and the 
 failure to properly reduce it, by grinding, before the completion of the 
 crown. 
 
 A proper and equally symmetrical alignment of the incisal end should 
 also be observed, and, while the occlusion may govern to some extent, it 
 is often permissible to grind interfering opposing teeth slightly to admit 
 of securing this. In this connection considerable trimming and shaping 
 
141 
 
 of the ends and uneven and irregular edges of natural teeth may often be 
 done to their improvement and benefit, and entirely without harmful or 
 injurious results, if done carefully and judiciously, such surfaces being 
 afterward polished smooth with fine disks. 
 
 As nothing in nature is more apparent than the 
 Color and I)armony. universal expressions of harmony, it is, of course, 
 essential in simulating it that every effort should be 
 expended, and every facilitity employed, to obtain this in the con- 
 struction of artificial crowns, that they may more closely resemble the re- 
 maining natural teeth. 
 
 The selection of a tooth or facing of the proper 
 
 Color. color, with due allowances for any change which may 
 
 be occasioned by the presence of a metal backing, or 
 
 other means of diminishing its translucency, is often a difficult and very 
 
 exacting" problem, and those who are so unfortunate as not to be endowed 
 
 with an accurate and artistic eye will often be seriously handicapped. 
 
 The color should be selected with these possible changes in view, and, 
 particularly in the restoration of the six anterior teeth, should usually 
 match the natural tooth corresponding to the one being crozvned (if pres- 
 ent), as a variation in the color of natural teeth in the same mouth is 
 marked, to which special attention has been given in a splendid contribu- 
 tion by Dr. E. C. Royce, of Chicago. If some variation seems unavoid- 
 able, a slightly darker shade is usually preferable to a lighter one, and 
 efifects a less conspicuous and in consequence more artistic result. 
 
 The use of the high-fusing oil colors, introduced 
 Oil Colors. by Mr. Robert Brewster, of Chicago, or a lower- 
 
 fusing variety made by C. Ash & Sons, makes it pos- 
 sible to obtain almost any desired variation of shade in a single facing, as 
 well as to more perfectly and artistically imitate the characteristics of the 
 remaining natural teeth. These are prepared in several basal or primary 
 colors, and in obtaining color and shadow effects are to be thinly mixed and 
 painted on the lingual surface of the facing, immediately after the grinding 
 has been completed, then placed in the furnace and fused, after which, 
 when the desired result has been obtained, the crown is constructed as 
 intended. 
 
 In reproducing pits, grooves, erosion, tobacco stains, etc., the colors 
 are to be painted upon the labial surface, after properly grinding, and then 
 fired before backing. 
 
 Harmony in shape, form and characteristics is 
 I)armony. scarcely second in importance to color, and at least 
 
 in salient features should be closely observed, as the 
 artistic possibilities increase in proportion thereto. 
 
142 
 
 The shape and general form of the porcelain tooth or facing should 
 be the same as the corresponding natural tooth (if present) ; the length 
 from cervical to incisal edges should be the same as the adjacent teeth; 
 the angles and incisal edge should be characteristic of the remaining teeth, 
 and in the event of the presence of numerous and conspicuous gold fillings 
 the artificial crown should be similarly treated. 
 
 In complying with such requirements too much 
 manufacturers' should not be expected of the manufacturers and 
 PifOdUCfS. supply houses, as it would be impossible for their best 
 
 efforts to be productive of results which could rea- 
 sonably be expected to be universally adaptable to all cases. Their prod- 
 ucts represent only the efiforts of the artisan in catering to the general 
 demand, and the successful operator only can and must become the artist. 
 A selection which approaches the requirements should be made, and 
 then ground and shaped as the characteristics of the case may indicate. In 
 
 f/c^. 123. 
 
 nearly all makes of porcelain teeth this can be done with impunity if the 
 surfaces so ground are afterwards repolished with fine disks, and the re- 
 sult is even more natural than the highly glazed surface. 
 
 It is this particular feature that should impel 
 Dental CaboratcriCS. the progressive, conscientious dentist to acquire such 
 skill as may enable him to execute his own work, for 
 the practice of relegating this class of work to dental laboratories, where, 
 in the majority of them, the motto observed in making bands is to have 
 them large enough to admit of easy and ready adjustment; where cusp- 
 forms are made by the office boy, by the score ; where the color is but a 
 chance; where accompanying instructions that the bite is normal will 
 suffice, and where time and revenue are necessarily the only serious con- 
 siderations, should be condemned as materially retarding the progress and 
 advancement of an artistic ,eld of professional effort. 
 
'43 
 
 metDoa of Construction. 
 
 In a consideration of the method of constructing this style of crown, 
 the consecutive stages of which are illustrated in Fig. 123, sjxjcial empha- 
 sis must again he given to the essentials of root preparation, and particu- 
 larly to the feature of allowing the end to project about one-sixteenth of 
 an inch from the gum until the peripheral trimming has been accom- 
 plished, the measurement taken, and the band fitted. 
 
 The importance of this procedure has already been sufficiently empha- 
 sized, and cannot be overestimated, as a neglect to observe or a disregard 
 of it will adfl materially to the difficulties encountered, and to the degree 
 of inaccuracy and discomfiture resulting. 
 
 f/(7./24. 
 
 When the remaining natural crown has been 
 Procedure. cut to the desired extent, and the projecting end 
 
 of the root properly trimmed, the measurement 
 should be taken in the manner already indicated. 
 
 A band should now be cut the exact length of 
 
 Bands. the measurement, about one-eighth of an inch wide, 
 
 and of 22 karat gold, 28 or 29 gauge in thickness. 
 
 The edges should be filed straight and smooth, 
 
 Soldering. and the band annealed and made into circular form. 
 
 By first overlapping and then abutting the ends, their 
 
 contact may be sustained when heated, as already described, and the joint 
 
 should be soldered from the inside with a minute bit of 22 or 20 karat 
 
 solder. 
 
 The first procedure incident to fitting the band 
 
 fitting. should be to give it a general shape approximating 
 
 that of the root, and then to trim the cervical edge to 
 
 closely follow the curvature of the gum, with the joint at the center of the 
 
 lingual surface. Curved pointed plate shears, or the crown shears espe- 
 
144 
 
 cially designed for such trimming (Fig. 124) may be used for this 
 pVirpose. 
 
 When thus trimmed so as to come in uniform contact with the gum 
 when loosely and temporarily adjusted to the end of the root, the edge 
 should be filed smooth with the convev surface of a fine half-round file 
 (Grobet, 4 to 5 inch, No. 5), and then nicely rounded, always avoiding a 
 thin feather-edge for the reasons mentioned. 
 
 The band should now be placed upon the projecting end of the root, 
 and then forced gently to position with a small piece of wood, until it 
 passes just freely beneath the gum. (Fig. 125, A.) 
 
 While the topical application of solutions of cocaine, carbolic acid, 
 etc., are frequently relied upon as a means of obtunding the pain, the use 
 of any therapeutic agent is seldom necessary where the band fits a pro- 
 jecting end of a properly prepared root, as this serves to first conform it to 
 
 ncf.125. 
 
 the proper shape, and then guide it to place, thus causing little, if any, dis- 
 comfort, A very great percentage of cases where any acute pain is occa- 
 sioned can usually be attributed to forcing the band into the tissue, instead 
 of its closely following the outlines of the root, and passing under and 
 within the free margin of the gum, without unnecessarily impinging upon 
 the periosteum or peridental membrane. 
 
 When the cervical end has been properly adapted, the band should be 
 removed and trimmed until the labial surface is as narroiv as pos- 
 sible to meet the requirements, but gradually sloping until it is somewhat 
 wider upon the lingual. 
 
 It should now be readjusted to the root and forced well to place until 
 it is Entirely invisible from the labial aspect. The root should then be 
 ground down until its basal surface follows the outlines indicated and 
 approximates the edge of the band. (Fig. 125, B.) 
 
145 
 
 While this relation may be obtained by grinding the root down with 
 the band in position, it is usually best to remove the band during the pro- 
 cedure, for the reason that it may become loosened from the vibration, and 
 slip downward unobserved, thus endangering the distortion of its shape ; 
 or, of being ground too narrow to be useful ; and the heat produced by 
 the friction is also an objection to grinding and shaping a band in the 
 mouth. 
 
 When thus properly trimmed, it should be removed with a small hook- 
 instrument, and the floor then attached. 
 
 The floor to the band, in the attachment of which 
 
 Tormins Cap. the cap is formed, should be thiji enough to be easily 
 
 adapted to contact with the edge of the band, and 
 admit of bringing the neck of the porcelain facing into close proximitv 
 with the gum. 
 
 Ficj.126. 
 
 For this purpose, platinum, about 34 gauge, is preferable, as afford- 
 ing the desired thinness without danger of being fused in the subsequent 
 final soldering of the parts ; although pure gold, or even gold of 22 karat, 
 of the same gauge, may be used. 
 
 Any special degree of strength in the floor itself becomes unnecessary 
 ui gold z^'oi'k, because of the quantity of solder which will be subse- 
 quently used in uniting cap and facing, and properly contouring the lin- 
 gual surface. 
 
 In soldering the floor to the band, a liberal surplus of the metal (gold 
 or platinum) should be used, and will facilitate the procedure. The band 
 should be placed in the center of this, without any special effort to secure 
 a perfect adaptation at this time, the parts then fluxed and attached at one 
 point of contact by the partial fusion of a small bit of 20 karat solder 
 
146 
 
 placed outside of the band. This will anneal the floor metal so that it may 
 readily be burnished to a perfect contact with the edge of the band ; and 
 absolute contact around the entire circumference is essential, as an opening 
 or space filled only with solder may be again opened by the re-fusing of 
 the solder in the final assemblage of the crown. In securing this contact, 
 however, care should be exercised to prevent changing the shape and form, 
 of the band. 
 
 After applying flnx, one corner of the floor should be grasped with 
 fine-pointed soldering pliers, and again carried to the flame, until the com- 
 plete fusion of the solder formerly used unites the' parts around the 
 entire joint. (Fig. 126.) It will seldom be found necessary to make a 
 second application of solder, for the quantity required, where good contact 
 exists, is almost infinitesimal. 
 
 After the soldering has been completed, the surplus of floor metal 
 should be trimmed close to the band, and the joint then finished down 
 smooth, with stones and disks. 
 
 When adjusted to position on the root, the cap should rest firmly upon 
 its seat, and any tendency to rock should be relieved. Rocking usually 
 indicates a high point on the extreme approximal edge, the removal of 
 which will overcome the difficulty. 
 
 Dowels. 
 
 The cap should now be removed, and the canal prepared for the re- 
 ception of the dowel, the requirements of which have been already out- 
 lined. 
 
 As the dowel assumes the greater portion of the strain to which the 
 crown will be subjected, the alloy of platinum and iridium is generally 
 used, because of its toughness and strength; and the round, square and 
 triangular wire, in sizes varying from 14 to 18 gauge, according to that 
 indicated by the proportions of the root, are prepared for the purpose. 
 
 The so-called "platinoid" and other German silver alloys are also 
 prepared and used for this purpose, but the only advantage possessed by 
 them is that of economy, and this is gained at the expense of stiffness,, 
 strength and permanent integrity. 
 
 If there is any preference as to the form of wire used, it is in favor of 
 the round, because of its being easier to remove from the canal after 
 mounting, in case of necessity ; and of its being perhaps also easier to per- 
 forate the floor of the cap in such manner as to secure a close contact 
 between it and the dowel at the line of junction, which facilitates and adds 
 strength to their union, and prevents the solder from flowing in upon the 
 under side of the cap. For this reason, should a square dowels seem 
 desirable, round wire, of heavier gauge may be used, and that part which 
 
H7 
 
 enters the canal filed square after fitlin<>- to the hole in the Hoor hut hefore 
 soldering. 
 
 The advantages claimed for the square and triangular forms are that 
 a wire drawn with sharp angles possesses greater strength and resistance 
 than a round one ; and that any possihle rotation of the crown on conical 
 roots, after mounting, is precluded. If the wire used is of adequate size to 
 meet the requirements, the round form possesses sufficient strength, how- 
 ever, and there can he no rotation, if the crown is well adapted and the 
 mounting is secure. 
 
 • In fitting to the canal a length should be cut which will afford some 
 surplus, and one end then slightly tapered. When thr dowel has been 
 properly prepared and adapted, the cap should be placed in position and 
 a large round or oval burnisher used to outline the opening of the canal, 
 in the floor. A small perforation through the center of this outline should 
 now be made with a sharp pointed instrument, or bur, and the dowel then 
 grasped -firmly with pliers and the tapered end forced through the floor 
 and into the canal until in proper position, which insures a close contact 
 between dowel and floor. 
 
 When properly adjusted, the relation should be at once permanently 
 sustained by soldering, to accomplish which base-plate gutta percha, tem- 
 porary stopping, or adhesive wax, should be warmed and packed around 
 the projecting end of the dowel, and over the surface of the cap. WHien 
 this is cool, which may be hastened by a spray of cold water, they should 
 be carefully detached from the root, and the interior of the cap filled with 
 plaster or investment material, until the dowel is covered. (Fig. 127.) 
 The use of any more investment material than absolutely necessary only 
 adds to the difficulty of soldering, and it is essential that it should be 
 packed down into the cap well to prevent burning the band. After this 
 investment has crystallized, the removal of the temporary medium, by 
 warming over the flame, will admit of securely attaching the parts with 
 solder by the use of the small mouth blowpipe. 
 
 In the event of accidentally making too large a perforation through 
 the floor, an additional piece of the metal of smaller dimensions may be 
 properly perforated and burnished down over the surface before removing 
 
148 
 
 and investing the cap and dowel, and subsequently attached at the time of 
 soldering. 
 
 The cap should be cleaned in. the acid bath after removing from the 
 investment, and then adjusted to position on the root and the bite and 
 impression taken. 
 
 In the construction of anterior crowns, the tak- 
 
 "BltC." ing of a "bite" usually becomes necessary only, when 
 
 some abnormality of occlusion, or irregularity of the 
 
 opposing teeth, presents. Otherwise the lingual contour of the adjacent 
 
 teeth as represented in the model will indicate the outlines to be followed 
 
 by this portion of the crown. 
 
 When a bite is necessary, it should be taken in wax, preceding the 
 impression, and should be secured in accordance with the requirements of 
 the impression, and in the manner previously outlined. 
 
 The impression should then be taken in plaster 
 
 Tmprcssion. for the reasons already stated, and should always in- 
 
 clude teeth on each side of the one being crowned, 
 and the corresponding toothy when present. 
 
 If the projecting surplus end of the dowel is slightly bent, the cap 
 will be removed with the impression, but in the event of its remaining upon 
 the root, it should be detached and adjusted accurately to position, and 
 securely sustained, if necessary, with a little melted wax. The interior of 
 the cap and the surface of the dovel should now he covered with a slight 
 film of melted zvax to facilitate and admit of its ready removal from the 
 model, and the impression then varnished and filled. 
 
 When the model has been obtained, the bite, if one has been taken, 
 should be adjusted, and the case mounted upon the articulator. The cap 
 may now be easily detached by grasping the end of the dowel with pliers, 
 and the wax then removed from its interior, which will admit of its ready 
 and accurate readjustment, thus facilitating the investment of the crown, 
 and permitting the preservation of the model. 
 
 In cases where the remaining natural teeth are quite loose, or support 
 artificial crowns of doubtful stability, the use of small particles of wax 
 packed into the interproximal spaces, and into all undercuts, will be found 
 to be advantageous to the removal of the impression, and to the comfort 
 of the patient. 
 
 Jldaptation of Tacinds. 
 
 Previous to the selection and adaptation of the facing, the surplus end 
 of the dowel should be cut ofif with excising forceps or cutting pliers, leav- 
 ing it as long as possible so as not to interfere with the adjustment of the 
 facing to its proper position. 
 
149 
 
 As the floor is very thin, however, some Httle surplus should always 
 be allowed to remain, in order to add strength to the attachment of the 
 dowel. 
 
 A long pin facing should now be selected and ground to a perfect 
 joint with the cap, along its cervical curvature, and then to meet the 
 requirements of length, contact and characteristics. 
 
 When this required and proper adaptation of the 
 
 Cerokal end, cervical end, to the cap, is secured, the inner surface 
 
 of the facing should be thinned down somewhat until 
 
 sufficient space exists to afford opportunity for securing a close joint 
 
 between the backing and the cap, with solder. 
 
 Ficj.l26 
 
 The incisal or occlusal end should now be bev- 
 eled about half-way to the pins, in order that it may 
 present a smooth, sharp angle, instead of the usual 
 rounding edge. (Fig. 128.) This becomes neces- 
 sary as a means of affording a definite edge to which the backing may be 
 subsequently finished. 
 
 Tnclsal or 
 Occlusal end. 
 
 The use of the clamp designed by Dr. A. Brom Allen, of Chicago 
 (Fig. 129) will be found convenient for holding porcelain facings while 
 grinding. 
 
 BacRitid of Tactiid. 
 
 The backing of porcelain facings becomes necessary in metal work 
 as a means of supporting them, by affording a surface which will admit of 
 their subsequent attachment with solder. 
 
 The requirements in this connection embrace two essential features : 
 First, the backing must be closely adapted to the porcelain, and, second, it 
 must be sufficiently strong, rigid and unyielding, to protect the porcelain 
 from the strain of mastication 
 
 While numerous methods are employed, the following will be found 
 
ISO 
 
 to be productive of the most certain and accurate results, though possibly 
 somewhat less expeditious than the more simple methods usually observed. 
 
 Pure gold, about 34 gauge, cut somewhat larger than the facing, and 
 to extend from cervical to incisal or occlusal edges, should be perforated 
 for the ready reception of the pins, annealed, and carefully burnished to 
 a perfect adaptation. 
 
 As it is desirable that the perforations should be properly placed, so 
 as to admit of the free and easy adjustment of the porcelain to position, 
 and to preclude any strain upon the pins in adapting the backing, it should 
 first be observed that the pins are straight and parallel with each other, and 
 that this surface of the porcelain is clean and free of wax. 
 
 As a means of ascertaining the exact position of 
 
 Adaptation. the pins, the gold should be laid on a smooth surface 
 
 and the facing placed over it, pins downward, and 
 
 sufficient pressure applied with the thumb to make a slight indentation. 
 
 Ficj.130. 
 
 Or, a thin film of melted wax may be previously placed on the surface to 
 facilitate this, though this is unnecessary because of the softness and 
 thinness of the pure gold. 
 
 The perforations may now be made with a punch designed for the 
 purpose, or with a sharp pointed instrument of proper size. The use of 
 the latter possesses the advantage of throwing up a small furrow of metal 
 around the holes, and is preferable. 
 
 After annealing and burnishing the gold to a perfect adaptation, the 
 surplus should be trimmed away to closely follow the porcelain on all sur- 
 faces except the incisal or occlusal, where a slight projecting edge should 
 be allowed to remain. 
 
 While the requirement of adaptation has now been complied with in 
 the best and easiest possible manner, that of strength is yet to be observed. 
 
 As the strain upon a facing is generally applied 
 Rt-cnf orcein cut. directly upon the end, and then diverted to the point 
 of resistance afforded by the pins, it is necessary that 
 a uniform re-enforcement extending over this area should be made. 
 
 To best obtain this, and thus combine the requirements of adaptation 
 and strength, a second piece of gold, preferably about 22 karat, 29 or 30 
 
i'^l 
 
 ■gauge, slioLild be perforated, hurnished to place, and trimmed to extend 
 from the pins to the incisal or occlusal end only, with a corresponding sur- 
 plus at the latter point. 
 
 The two backings should now be adjusted to po- 
 Solderlnfl. sition on the facing and reburnished, then removed, 
 
 placed together with the holes approximating each 
 other, which is facilitated by the furrow of metal produced by being 
 punched with a sharp instrument, and theq attached with 20 or 18 karat 
 solder. Small pieces of the latter should be consecutively applied to the 
 joint between the two, presenting toward the cervical end, until the inter- 
 vening space is completely filled, which may be easil}- and quickly accom- 
 plished by grasping the backings with the soldering pliers, as indicated in 
 Fig- I30> the use of which securely sustains their relation, and precludes 
 any distortion of shape. 
 
 The use of an excess of flux should be avoided, and care must be ex- 
 ercised to prevent the solder from filling the perforations, or flowin<y 
 through to the under side of the backing, and thus destroying the adapta"^ 
 tion. The latter may be easily avoided by coating this surface with a solu- 
 tion of whiting, but is usually prevented by the upturned edges surround- 
 
 ing the perforations, which also generally precludes their filling up with 
 solder. The use of small pieces of graphite from an ordinary lead pencil, 
 trimmed to snugly fit, and to project slightly from each side, will also 
 overcome any such tendency. 
 
 When the soldering has been completed, the backing should be 
 cleaned in acid, adju=,ued to position on the facing (Fig. 131, A), and se- 
 curely retained by bending the pins down close upon it, as indicated in 
 Fig. 131, B. Care must be exercised in bending the pins to catch them 
 with pliers at the extreme end, in order to avoid any stress or tension 
 which might result in immediate or subsequent fracture of the porcelain. 
 
 In finishing, the gold should be trimmed down to 
 TInlsblng. close contact with the porcelain around all surfaces. 
 
 This should be started with a fine file, always carry- 
 ing it tozvard the porcelain; and completed with disks, to insure the re- 
 
152 
 
 moval of all overhanging edges, the presence of which will invariably 
 cause fractures of the porcelain along the edges, due to the impingement 
 afforded by the shrinkage and contraction of the metal after soldering. 
 
 In trimming away the surplus from the incisal or occlusal portion the 
 file should be held on a parallel line with the labial or buccal aspect of the 
 facing. This leaves the backing its full thickness along this edge, the vul- 
 nerable point, when it may be afterward rounded nicely until practically 
 invisible, and yet always remain sufficiently long and strong to afford 
 ample protection to the porcelain. (Fig. 131, C.) Much of the artistic 
 effect of the finished crown will depend upon obtaining and preserving 
 a perfect joint between the neck of the facing and the cap, and while it 
 is the usual practice to grind this portion of the facing thin, and allow 
 the backing to extend entirely over it, forming a joint with the cap which 
 is subsequently filled with solder, the best results may be secured by 
 filing or grinding away this edge of the backing until the edge of the 
 facing nuiy be placed in direct contact zvith the cap. 
 
 This admits of bringing the facing into closer proximity with the 
 gum and of securing a better and more perfect joint between backing and 
 cap, because of the difficulty and uncertainty usually experienced in 
 successfully filling this space with solder. 
 
 The use of the clamp previously mentioned may also be found ser- 
 viceable as a means of holding the facing while finishing the backing. 
 
 As the double backing may seem unnecessarily 
 Uariation In UlCtftOfl. difficult or circuitous, various other methods are em- 
 ployed in preference, but probably with results less 
 certain and accurate. 
 
 The re-enforcement of the single pure gold backing may be done with 
 a lower grade of gold, or with solder alone, either preceding its final 
 adaptation to the porcelain, or at the time of soldering the facing to the 
 cap. There is no objection to this, procedure if adequate re-enforcement 
 is secured, but as gold or solder in fusing flows to a thin edge, the edges of 
 the backing and particularly the incisal or occlusal, where strength is de- 
 manded, are quite naturally the thinnest, and consequently the weakest 
 portions. 
 
 This may be overcome somewhat by allowing a slight surplus to ex- 
 tend beyond the porcelain, especially upon the incisal or occlusal end, until 
 after re-enforcing, and then adjusting to position on the facing, and se- 
 curely attaching and finishing, as indicated. In no event, however, when 
 a single pure gold backing is used, is it advisable to defer the re-enforce- 
 ment until the final soldering of the crown. 
 
 Where a single backing seems indicated or desirable, it should be 
 made of 22 karat gold, about 28 or 30 gauge, but as the burnishing to the 
 
153 
 
 poraelain is thus made more difficult, the additional stiffness and strength 
 is usually obtained at the expense of the adaptation. 
 
 The adaptation of heavy single backings may be materially improved 
 by swaging. For this purpose a mould of the lingual surface of the porce- 
 lain should be secured in mouldine, and fusible alloy dies obtained, and 
 dies made of ordinary sealing wax, or hard modeling compound are also 
 sometimes used. This consumes even more time, however, than the adapta- 
 tion of the double backing, and the results are less accurate. 
 
 As porcelain facings are more or less transparent. 
 Use Of Platinum. the presence of a gold backing is frequently objec- 
 tionable in the blue and lighter shades, because of the 
 yellowish cast imparted to them ; hence the placing of a surface of plati- 
 num next to the facing is sometimes indicated as a means of preserving 
 the original color, or of effecting the least, or most desirable, change in it. 
 
 For this purpose, platinised gold is employed, and possesses the ad- 
 vantage of affording a surface of either gold or platinum, as the case may 
 require. A more convenient method, however, is to back up the facing in 
 
 the usual manner, and then insert a piece of platinum foil (i-iooo) over 
 the desired area between facing and backing, just previous to permanently 
 attaching them by bending the pins, and finishing the backing to its proper 
 adaptation ; by which means equally good and perhaps quicker results may 
 be obtained. 
 
 When the adaptation and finishing of the back- 
 Tnoesting. ing have been completed, the facing should be ad- 
 
 justed to position on the cap, and the proper relation 
 sustained with wax. The crown should now be removed from the model, 
 and the joint between cap and backing well filled with melted wax. This 
 keeps it clean and free of investment material, which is essential to 
 securing a smooth flush joint with solder, and the latter may be facilitated 
 by using fluxed wax. 
 
 Investment material should now be mixed to a thin plastic consist- 
 ency, and a sufficient quantity poured upon the surface of a clean piece of 
 paper. The interior of the cap should first be thoroughly filled, and the 
 
154 
 
 crown then gently forced into the investment, until only the wax remains 
 exposed. After hardening, the surplus sliould be trimmed to the outlines 
 indicated in Fig. 26, and the wax carefully removed with a small pointed 
 knife-blade, being particular not to loosen the facing in its matrix. 
 
 In those cases where the backing has been allowed to extend en^tirely 
 through between facing and cap some difficulty is occasionally experienced 
 in getting the solder to flow nicely into the joint, and while this may usu- 
 ally be accomplished by properly fluxing and heating the case before at- 
 tempting to solder, if the proximity of the surfaces is very close the same 
 may be greatly facilitated by placing a small projecting bead of wax 
 around the immediate outside of the joint, before investing (Fig. 132, A). 
 When melted and subsequently absorbed and burned out, this leaves a 
 small- space into which the heat becomes concentrated, during the process 
 of soldering, and this aids materiall}- in drawing the solder toward that 
 po-int. 
 
 The cutting of a small opening through the under surface of the in- 
 vesfepient until the joint is exposed is also recommended for this purpose, 
 and the same may be easily obtained by extending the bead of wax previ- 
 ously mentioned until it is of proportions sufficient to leave such an open- 
 ing after its removal. (Fig. 132, B.) 
 
 In cases where two or more individual crowns, approximating each 
 other, are being constructed at the same time, they should always be in- 
 vested separately, as it is often quite difficult to solder them, when con- 
 tained in the same investment, without attaching them together. 
 
 Previous to heating the case for the purpose of 
 Soldering. final soldering, and after the investment has been 
 
 properly trimmed, and all debris removed, liquid flux 
 should be applied to the surface of cap and backing, and worked well down 
 into the joint. If the latter is done after the case is heated, or if powdered 
 flux is used, its penetration to the full depth of the joint is made more 
 doubtful. 
 
 The case should now be placed over the flame and gradually heated 
 ■until red; when medium-sized pieces of solder, previously fluxed, should 
 l)e separately and consecutively applied, and fused, until the joint is first 
 jfilled, and the desired contour obtains. If the case is properly heated, this 
 can be easily and readily accomplished with a small pointed flame from the 
 blowpipe. 
 
 When the soldering has been completed, the crown should be allowed 
 to cool slowly by gradually diminishing the size of the flame under it, until 
 it may be turned off entirely. Many prefer to place the work in a cooling 
 oven, or to submerge it into dry plaster until cold, but either procedure is 
 entirely unnecessary. 
 
155 
 
 After cooling sufficient!)-, it should be removed 
 Tinishind. from the investment, treated to the acid bath, and 
 
 then finished with stones and disks in the engine, and 
 subsequently polished on the lathe, when it is ready for mounting. 
 
 Jipplicatioti or Partial Bands. 
 
 The application of a partial band encircling only the approximal and 
 lingual surfaces of the root is advocated and employed more or less 
 frequently in the construction of dowel crowns, as a means of avoiding 
 the presence of a labial band, from an esthetic standpoint, and of pre- 
 cluding its possible irritating influence, as a prophylactic measure. 
 
 A consideration of the comparative advantages 
 
 Comparative leads to the conclusion that_, while a band encom- 
 
 JldvantagCS. passing the entire circumference doubtless adds 
 
 greater stability to the attachment of the crown, 
 affords a more perfectly hermetical sealing of the end of the root, over- 
 comes the possibility of fracture, may be made practically invisible, and 
 will not necessarily prove a source of irritation, providing that it fits, the 
 partial band, if well adapted to the lingual and approximal surfaces, 
 fortifies the attachment against stress in the direction from which stress 
 is exerted, makes it possible to bring the facing into absolute and direct 
 contact with the tissue, and precludes any irritation at this point, or the 
 conspicuous and objectionable appearance of the band in the event of 
 subsequent recession of the tissue. 
 
 The indications for the application of this mode 
 
 Indications, of construction are more or less general, but depend 
 
 much upon personal experience and preference, com- 
 bined with a careful observation of the particular requirements of the 
 case tinder treatment. 
 
 Of special indications, the most favorable are those cases where the 
 root is sufficiently strong to insure permanent support to a crown ; or 
 where the labial portion of the root may have ' been destroyed to the 
 border of the alveolus ; where the extreme shortness of the crown, or 
 the thinness and transparency of the tissue surrounding the root, would 
 likely show the presence of the band; where recession of the gums has 
 exposed the labial portion of the root ; and where pathological conditions 
 alreadv exist, or the tissue may seem to be particularly susceptible 
 to any possible irritating influence. 
 
 Procedure. 
 
 While several methods of securing the desired adaptation are em- 
 ployed, the most positive and accurate results may be obtained by fol- 
 
iS6 
 
 lowing the same detail of procedure indicated for a circular band, up to 
 and including its fitting, shaping and trimming, as previously outlined. 
 
 When the band has been thus fitted and trimmed, a floor of platinum- 
 or pure gold, about 34 gauge, should be first simply attached to the lingual 
 surface by the partial fusion of a small piece of solder. The floor should 
 then be adapted closely to the entire edge of the band, and a precaution- 
 ary measure observed to prevent their union with solder along that edge 
 of the band which is to be subsequently cut away. To accomplish this, 
 such portion of the joint between floor and band should be filled with a 
 solution of whiting, or occupied by a thin piece of mica (Fig. 133 A) 
 and the soldering completed around the approximal and lingual sur- 
 faces. 
 
 The surplus floor metal should be trimmed off on a line with the- 
 band, and the labial portion of the latter cut away to the desired point 
 with curved shears, always leaving the edge nicely rounded. (Fig.. 
 133 B.) 
 
 a 
 
 Fiq,l33. 
 
 When the trimming and finishing of the cap have been completed, it 
 should be adjusted to position on the root, and the projecting labial portion 
 of the floor burnished to a close adaptation to the surface and to the per- 
 ipheral outline. 
 
 The dowel should be fitted and subsequently soldered, and the impres- 
 sion then taken, and the crown completed as already outlined. (Fig. 
 
 133 C.) 
 
 A method wherein only a partial or semi-circular band is fitted to 
 the root instead of a circular one, and where the floor is then attached 
 and adapted by burnishing, is sometimes employed, but while this requires 
 less time, the adaptation is also less accurate. 
 
 Jlpplicaticn of Rii^eted Tacinds. 
 
 Because of the apparent dread exhibited by those of limited con- 
 fidence or experience, towards the process of soldering anything necessarily 
 involving porcelain, for fear of checking it, and of its possible change of 
 color as a result of the application of heat, a method has been devised- 
 
157 
 
 whereby the occurrence of either or both of these objectionable features 
 might be entirely and positively eliminated. 
 
 The process defers the permanent attachment of the facing to the 
 backing until after the construction and assemblage of all the metal parts 
 of the crown, after which it is then securely anchored by riveting the pins. 
 
 While there are probably no particular objections to this method, 
 except that the facing is held less rigidly, there are no special advantages 
 apparent because of the limited possibilities of checking facings, which 
 have been previously mentioned in connection with "Soldering," and of 
 the fallacy of a probable change in color resulting from the heat of 
 soldering. 
 
 That any perceptible change of color is due mainly to the presence 
 of the backing, and not to the heat, is proven in porcelain work, where, 
 when necessarily subjected to a very much higher degree, it is even then 
 the rare and exceptional occurrence ; and it would also seem that the 
 
 Ficj,l34- 
 
 impact and vibration produced by subsequently riveting the projecting 
 ends of the pins down close upon the backing would be equally as "haz- 
 ardous" a process as that of soldering. 
 
 Procedure. 
 
 In the construction of crowns by this method the same general 
 details as previously outlined are observed up to and including the adap- 
 tation of the backing. 
 
 When this has been accomplished it should be adjusted to position on 
 the facing and finished down as desired, in the usual manner, except 
 that the pins are not bent to sustain the relation of the two during the 
 process. 
 
 Facing and backing together are placed in proper relation to the 
 cap and sealed with a small quantity of hard or adhesive wax in such 
 manner as to securely attach the backing, but to allow the projecting ends 
 of the pins to remain freely exposed. (Fig. 134 A.) 
 
158 
 
 The crown should now be gently removed from the model and the 
 facing carefully detached from the backing. 
 
 Small pieces of graphite trimmed from a lead pencil are then closely 
 fitted into the holes in the backing and allowed to project far enough on 
 each side to be securely held by the investment, and to admit of properly 
 forming the lingual contour with solder without being covered over. 
 (Fig. 134 B.) 
 
 The remaining incisal portion of the lingual surface of the backing 
 should be covered with wax to keep it clean, and the crown invested. 
 Upon the subsequent removal of the wax the parts should be freely 
 exposed, fluxed, heated and soldered as usual, being careful to note that 
 the ends of the graphite pins are not covered, and that the solder does not 
 penetrate to the under surface of the backing, which is prevented by 
 painting around the pins with whiting. 
 
 /^/,y./3J. 
 
 When the soldering has been completed, the graphite may be broken 
 off even with the surfaces and removed from the holes by the use of a 
 sharp pointed instrument or bur of the same diameter. 
 
 The facing should now be adjusted to position and the lingual surface 
 of the crown trimmed to allow a free exposure of the projecting ends of 
 the pins. The holes should then be slightly countersunk with a round bur, 
 the crown roughly finished with stones and disks, and the facing finally 
 adjusted for riveting. 
 
 As a means of facilitating the process of riveting, 
 RiPCtlng. and of lessening the liability of fracturing the porce- 
 
 lain, the riveting forceps designed by Dr. Frank A. 
 Brewer, St., may be used to advantage; or the crown may be invested, 
 facing downward, in a base of plaster about an inch in depth (Fig. 135) 
 and the riveting hammer used. In the latter method the projecting ends 
 
159 
 
 of the pins are flattened flown over the backing sc-jjaratelv, 
 with moderate and well-directed blows from a small ri\'etin}^ hammer. If 
 the crown is properly invested, with a sufficient depth of plaster beneath 
 and supporting the facing, and the whole rests upon a firm seating, this 
 may be done wdthout danger of fracturing the porcelain. The riveted ends 
 are then smoothed down with disks and the crown finished and polished, 
 l)urnishing the metal up close to the porcelain around ihe edges. 
 
 Jlpplicdtion of Detachable and Replaceable Tacin^s. 
 
 The not infrequent presentation of broken facings resulting after the 
 permanent mounting of the crown, combined with the more or less diffi- 
 cult operation of replacing them in a secure and artistic manner, lias 
 resulted in the introduction of various means for overcoming the former 
 and simplifying the latter. 
 
 Several varieties of detachable and replaceable facings are designed 
 for this purpose, and are applicable to the construction of dowel crownis 
 as well as bridgework, though perhaps more generally so to the latter. 
 
 While, as a usual thing, it must be granted that the subsequent frac- 
 turing of a porcelain facing is due to one of two causes, i. e., either faulty 
 adaptation of the backing, wdierein it afifords insufficient strength or 
 inadequate protection, or a total disregard of the requirements of occlusion, 
 the use of a style which is easily replaceable is doubtless an advantage in 
 some instances. 
 
 When these common faults in regard to backing the facings are com- 
 bined with the severe strain to which the porcelain is often subjected in 
 some conditions of occlusion, and the perhaps unnecessarily rough usage 
 sometimes unconsciously accorded them, any practical means of facilitating^ 
 repair in the event of accident is materially useful. . . ,j. 
 
 The advantages claimed by the advocates of this- 
 Hdoantaacs Claimed, style of facing are: First, that the porcelain is not 
 subjected to the heat of soldering; second: facings^ 
 may be more easily replaced in the event of becoming fractured; thircfr 
 the probability of becoming fractured from usage is greatly diminshed 
 because the facing is not so rigidly attached to the metal backing; fourth, 
 the color is not changed. 
 
 The first point made is practically the zveakest, 
 JIdPantases Considered, because the fracturing of a facing during the process 
 of soldering it to any kind of an attachment is inex- 
 cusable, and can be invariably attributed to either a lack of skill or a 
 neglect of detail. 
 
 The second must be regarded as problematical, at least in the manner 
 
i6o 
 
 in which these facings are ordinarily used, for the reason that it is often 
 impossible to properly adapt any style or kind of facing to the individual 
 case without considerable grinding. 
 
 For this reason also the subsequent replacement of even an exact 
 duplicate of the same mould would occasion the necessity for grinding 
 the latter to . an. accurate fit and adaptation with the stationary backing, 
 and to meet the esthetic requirements, which, irrespective of the manner 
 of attachment, is not usually an easy or simple procedure. 
 
 The third feature presents the most practical and plausible advantage, 
 Ijecause a porcelain facing supported by mechanical means supplemented 
 with an intervening medium such as gutta percha, or even cement, which 
 a€ords a somewhat cushion-like effect, will withstand greater stress than 
 one held firm and rigid. Hence fracture is, of course, less likely to occur 
 since'the- facing willyield slightly to stress before breaking. 
 
 The fourth point of advantage is doubtful, for the reason that any 
 change of color is usually due to excessive heat, or the presence of the 
 backing, as has been previously mentioned. 
 
 ■' : ■ >• If the highest advantages are to be obtained ini 
 
 • ■ TldVinttagCS the use of this style of porcelain facing, the adoption 
 
 '"'Obtainable. of a method suggested and practiced by Dr. F. T. 
 
 Van Woert and others will be found most practicable. 
 
 This consists of properly grinding and adapting two or more facings 
 of the same color and mould, as the conditions of occlusion may seem to 
 indicate, for each case at the time of construction. Those not used in 
 completing the crown are then placed in small boxes or other convenient 
 receptacles and labeled with the patient's name. In case of breakage occur- 
 ring at any subsequent time, a duplicate requiring no fitting or grinding, 
 and which may be readily adjusted to position, is conveniently obtainable. 
 
 While such a procedure may involve considerably more work at the 
 time, much may often be saved in the long run, and particularly in difficult 
 cases, where much grinding is necessary. 
 
 Uarious Designs. 
 
 Of the various designs of detachable facings now procurable, the 
 demand has seemingly not justified the adoption of any one special make 
 in preference to the others, nor their extensive manufacture in any great 
 variety of moulds and colors. 
 
 The design of removable or detachable facing 
 
 mason's Tacind. devised by Dr. W. L. Mason, of Red Bank, N. Y., is 
 
 probably the most extensively used. It consists of 
 
 a heavy gold backing having a triangular slot through the center and a 
 
 tacing.with a projecting corresponding triangular platinum bar extending 
 
i6i 
 
 longitudinally, through tlie center, which readily telescopes into the slot 
 in the hacking. (Fig. 136 A.) 
 
 These facings are oljtainahlc in a fairly good variety of moulds and 
 colors, and the principle of attachment is secure and admits of easy adjust- 
 ment. The objectionahle features lie in the seemingly excessive proportion 
 of platinum baked in the porcelain, which floubtless weakens the latter by 
 <lividing it through the center, and in the necessary thickness at the incisal 
 or occlusal end. 
 
 In the application of this style of facing the cap 
 Application. should be completed as prescribed, and the models 
 
 obtained and mounted upon the articulator. After the 
 selection of the facing its backing should Ije adjusted and two facings, in 
 situ, ground to fit the cap and to conform to the usual requirements. When 
 the desired adaptation is secured the relation to the cap should be sustained 
 by attaching the backing to it with hard or adhesive wax, and the facing 
 -then detached, which is facilitated by a projecting end of the platinum bar 
 
 DD 
 
 ^f./3e. 
 
 at the incisal or occlusal edge. Care should be exercised in securing a 
 close relation between the backing and the cap, in order that any penetra- 
 tion of solder through the joint may be precluded, and this may be further 
 prevented by filling the slot and coating backing with whiting. The 
 •metal parts should now be invested and soldered, with due attention to 
 the desired lingual contour. 
 
 After soldering, the crown should be finished (Fig. 136 B), and the 
 facing then adjusted to position. The projecting end of the platinum bar 
 should now be cut off and the facing attached to the backing with a thick 
 solution of gutta percha in chloroform, after which the edge should 
 -be finished up close to the porcelain, and the crown mounted. Or, if 
 desirable, the setting of the facing may be made after the crown has been 
 attached to the root and cement is also some times used. 
 
 A recent design of removable facing has been 
 Koacb'S Tacina. devised by Dr. F. E. Roach, of Chicago, and for sim- 
 plicity and strength, combined with accuracy of adap- 
 tation, and ready application to either individual crowns or dummies tor 
 
1 62 
 
 bridgework, it presents many favorable features. The design consists of 
 a facing with a dovetail lug extending lingualh', which is stamped of one 
 piece of iridio-platinum (Fig. 137 A), and a backing with a slotted 
 diaphragm into which the lug fits accurately (Fig. 137 B). 
 
 The lug is placed vertically m the body of the facing, and, being 
 entirely surrounded by porcelain, affords to the latter a maximum degree 
 of strength, and is set at an angle which admits of easy adjustment to the 
 backing. 
 
 The hacking is composed of two parts securely united. The outer 
 portion, which is of pure gold, about 34 gauge, is intended to facilitate 
 ready and accurate adaptation to the porcelain, after grinding; and the 
 central portion, which affords the means of attachment, is in the form 
 of a slotted diaphragm, made of 26 gauge clasp metal. 
 
 While the principle of attachment is good and secure, the pliability 
 of the outer backing insures a close adaptation to the surface and edges 
 of the porcelain ; the gingival extension admits of a close joint between 
 
 FicjJ37, 
 
 facing and cap, and no excess metal exists at the incisal end to offer 
 obstruction to the occlusion, the merits and demerits of these facings, 
 and their possibilities, range of usefulness and general application are 
 at present uncertain, because of the limited supply and selection procurable. 
 
 After constructing the cap and obtaining models, 
 
 npplicaticn. the facing should be selected and ground to place, 
 
 closely following the method previously outlined with 
 regard to the cervical and incisal preparation. The backing should then 
 be adjusted to place on the facing and burnished to a close adaptation 
 with the porcelain, after trimming away all unnecessary surplus around 
 the edges. 
 
 The two should then be placed in position on the cap and the relation 
 sustained with hard wax (Fig. 137 C), the facing removed and the metal 
 parts invested and soldered (Fig. 137 D). 
 
 After finishing the crown the facing should be attached with cement, 
 or gutta percha, and the crown mounted. Because of the extreme thinness 
 
i63 
 
 an4 pliability of the backing surrounding the attachment, this style of 
 facing is also applicable to the construction of the sheU or telescope crown 
 with porcelain facing, and to bicuspid and anterior dummies for 
 bridgework. 
 
 Another design has recently been devised by Dr. 
 
 DwIgbt'S Tacinfl. W. H. Dwight, of Le Mars, Iowa. This consists of 
 
 a facing containing a countersunk platinum socket, 
 
 which engages the arms of a bifurcated spring post, with threaded shank, 
 
 which is to be previously attached to the backing (Fig. 138 A). 
 
 In the application of this principle the cap should 
 Jlt),pliC<ltion. be constructed as indicated, and the models secured. 
 
 The facing should then be selected and ground to place 
 with the incisal end properly beveled to afford protection. By heating the 
 facing and pressing its labial or buccal surface against a small piece of 
 ordinary sealing wax it may be conveniently handled during the process 
 of adaptation. 
 
 When the grinding has been completed the spring post should be 
 inserted in the socket of the facing and the end of its projecting shank 
 imprinted in the surface of a piece of pure gold, about 34 gauge, to 
 denote the location of a perforation for it5 reception. 
 
 The perforation should then be made with a punch or small sharp- 
 pointed instrument, and the projecting threaded shank screwed into it 
 until the backing approximates the shoulder of the post. This may be 
 facilitated by leaving the facing attached or by the use of a wrench 
 designed for the purpose. The facing should then be removed (Fig. 
 138 B), and post and backiUfg permanently attached by the use of a small 
 quantity of solder fused around the line of junction upon the surface to 
 be placed nest to the porcelain, in order to stiffen and strengthen 
 their union. 
 
 The facing is now replaced and the backing burnished and trimmed 
 to a proper adaptation with the porcelain and then placed in position on 
 the cap and the relation sustained witlj hard wax. 
 
164 
 
 After removing the porcelain the inner surface of the backing should 
 be coated with a solution of whiting and the parts invested, soldered and 
 finished (Fig. 138 C). In permanently attaching the facing to the crown 
 the arms of the post should be expanded until it becomes necessary to use 
 some little pressure in forcing it to place, as they are purposely left 
 slightly contracted, in order to admit of easy adjustment during the 
 process of adaptation. 
 
 The facing should then be cemented to place and the crown polished 
 and mounted. 
 
 The same principle is also applicable to the replacement of broken 
 facings on crowns otherwise constructed, and will receive subsequent 
 consideration in that connection. 
 
 While the details are expeditious and simple, the principle involved 
 in this style of attachment seems weak, from the fact that the mechanical 
 fixation is insecure, and depends much upon the presence of cement for 
 the necessary strength. 
 
 The method of constructing a replaceable facing, 
 
 Bryant's IllCtftOd. devised and practiced by Dr. Emory A. Bryant, of 
 
 Washington, D. C, consists of forming a box for 
 
 the accommodation of the pins as a portion of the backing, and is 
 
 applicable to any size of the ordinary cross-pin flat-back facings, and to 
 
 the construction of bridgework as well as single crowns. 
 
 In the application of this method the facing 
 
 Application. should be selected and ground to the proper and 
 
 desired adaptation, after which it should be backed 
 with pure gold or platinum (34 to 36 gauge), as the requirements of 
 construction may indicate. 
 
 In the box method a pair of Barnard's parallel 
 
 Box ntctbod. pliers, modified by the addition of a set screw and 
 
 by grinding down the ends of the beaks to approxi- 
 mate the diameter of the pins of the facing, as indicated in Fig. 139, are 
 now accurately adjusted to the relation of the pins, and a strip of platinum, 
 36 gauge, somewhat wider than the length of the pins, is then wrapped 
 around the points of the pliers, forming a box for the reception of the 
 pins. 
 
 After soldering the joint, backing and box are adjusted to position 
 on the facing, and their relation marked with a sharp-pointed instrument, 
 after which they are removed and attached by soldering. The two per- 
 forations for the pins should now be extended into one by cutting out 
 the metal between them with a fissure bur of about the same diam- 
 eter (Fig. 140 A). 
 
 This should then be readjusted to position on the facing, and the inner 
 
i65 
 
 edge of the box, and the ends of the pins trimmed to approximate, and 
 until the projection offers no obstruction to the desired contour or occlu- 
 sion. A cover of 22 karat gold, about 28 gauge, somewhat larger than 
 the box, is soldered to this edge from the outside, and subsequently 
 trimmed until all surplus is removed, which completes the construction 
 of the backing. (Fig. 140 B.) 
 
 The facing should be prepared by slightly serrating the surfaces 
 of the pins which present toward each other, and then filling the space 
 between them with soft solder, using enough to fill it at least equal to 
 the length and thickness of the pins. 
 
 This may be easily done by first fluxing the 
 pins with soft solder flux, placing the soft solder 
 or fusible alloy in position, and carefully direct- 
 ing the flame upon the porcelain, until it takes 
 hold of the pins, after which it should be quickly 
 plunged into cold water to preclude an expan- 
 sion of the pins, which might cause fracture of 
 the porcelain. Or the facing may be placed on 
 a charcoal block or asbestos pad, pins upward, 
 
 BqJ^O 
 
 and the solder fused by carefully directing a small flame upon the 
 porcelain. 
 
 This extension of soft solder should be filed down even with the 
 pins on all surfaces (Fig. 140 C), except that the extreme end should 
 remain a shade heavier or thicker, to facilitate the subsequent attachment 
 to the backing with cement. 
 
 Facing and backing should be adjusted, placed in proper relation 
 with the cap and temporarily attached with hard wax. The facing should 
 then be removed and the box filled with moistened whiting, and a staple 
 of German silver or iron wire inserted, with the ends projecting about 
 one-quarter of an inch. This prevents the solder from penetrating the 
 interior of the box, and precludes any change in the relation of box and 
 backing during the process of soldering. The parts should be invested, 
 soldered and finished as usual and the facing then mounted with 
 cement. 
 
i66 
 
 A similar method involves tlie like adaptation of 
 
 Cube Illi^tbOd', a separate tithe to each individual pin, but as this 
 
 entails much more work, possesses less strength and 
 
 affords less opportunities for replacing the facing in case of accident, it 
 
 has been almost entirely superseded by the former procedure. 
 
 The merit possessed by these methods lies in the facility with which 
 a replaceable facing and its attachment may be constructed, and the main 
 advantage in their use may be attributed to the fact that the facing is not 
 held so unyieldingly rigid as if soldered. 
 
 Among other advantages possessed by the Davis 
 Davis 0fOWtt$. crown is also that of being easily replaceable in case 
 of breakage, but as this style of crown in the various 
 phases of its application will receive due and separate consideration, fur- 
 ther reference to it in this connection wdll be deferred. 
 
 Jfpplication to Bicuspids and molars. 
 
 The band and dowel style of construction is applicable to the restora- 
 tion of the crowns of bicuspids and molars as well as to the anterior teeth, 
 but is more generally indicated and more extensively employed upon 
 bicuspids than upon molars. 
 
 While it is especially indicated in porcelain work, 
 Indications. wdiere the root is necessarily and purposely trimmed 
 
 to approximate the gingival line, it is also indicated in 
 combination with gold, in order that the work may more closely approach 
 the highest esthetic requirements. In this connection, and in the absence 
 of facilities for doing porcelain work, a facing, or saddleback or rubber 
 tooth may be used with artistic results, and particularly where the short- 
 ness of the root demands the employment of a dowel attachment, in prefer- 
 ence to restoring its coronal proportions with amalgam, and using a shell 
 or telescope crown. 
 
 The application is more generally indicated and 
 Bicuspids. more practical on the bicuspids, because of the 
 
 necessity for observing higher artistic possibilities, 
 and of the objection to placing gold crowns upon these teeth. 
 
 In the restoration of molars, however, the indica- 
 ntOlars. tions are not so general, and the range of application 
 
 is more limited, for the reasons that such crowns are 
 usually beyond the range of vision, at least to an extent which greatly 
 diminishes the esthetic requirements; that they are subjected to more 
 vigorous strain in the act of mastication, and that a telescope attachment 
 to a projecting end of the root doubtless affords greater strength and 
 
i67 
 
 more permanent stability than is usually obtained by cutting the 
 remaining root down to the gingival line and using a dowel attachment. 
 
 It is claimed by some, however, that the preparation of a short root 
 and the subsequent adaptation of a narrow band, with accuracy, is so 
 facilitated as to present advantageous features, as compared with the more 
 extensive preparation of the remaining coronal proportions of the root for 
 the shell or telescope crown. 
 
 Yet such a claim . everts to the manner of the execution of the neces- 
 sary details, and as they must be carefully and skilfully observed in either 
 instance, the advantage seems more hypothetical than practical, and the 
 judicious preservation of tooth structure combined with the stability of 
 attachment as applied particularly to the molar teeth, for the reasons 
 mentioned, should precede a consideration of facility and possible advan- 
 tages in the construction. 
 
 Procedure. 
 
 In the construction of this style of crown, in combination with gold, 
 two more or less practicable methods are employed, and they differ only 
 in the style of porcelain facing or tooth used. The cap should be com- 
 pleted as though for an anterior crown, as described, and the dowel fitted 
 and soldered. 
 
 Where a heavier and stronger cap than will be 
 Rccnforced Cap. afforded by the thickness of the band is indicated or 
 desirable, the same may be obtained by allowing the 
 floor to extend or project about Vg, of an inch from the band, and then 
 filling in until flush and smooth with 22 or 20 karat solder. This will 
 result in a cap possessing good adaptation, a maximum degree of strength 
 and a minimum tendency to cause irritation, such as is frequently 
 indicated in the restoration of bicuspid crowns. 
 
 If the use of two dowels should become necessary 
 Use Of two Dowels, to insure sufficient stability, care should be observed 
 to have them inserted at such an angle as to pass into 
 the root readily, and yet project through the floor of the cap at a point 
 at which they will offer little, if any, obstruction to the proper adjustment 
 of the facing. While the surplus ends may be cut away reasonably close 
 to the floor after soldering, the longer they may be allowed to remain the 
 greater the strength of their attachment to the crown. 
 
 The bite and impression should follow in the 
 BffC and TmprcssiOtt; "sual manner, and the models then be obtained and 
 mounted upon the articulator. 
 
i68 
 
 Use of Tlat-Back Taciitd. 
 
 The method perhaps most usually employed involves the use of a 
 flat-back facing and gold cusps, and while this style of construction pos- 
 sesses the advantage of strength, it also presents the objectionable feature 
 of the presence of an occlusal surface of gold. 
 
 The facing should be selected and ground to 
 Taciltfl. position on the cap, and the occlusal end then ground 
 
 to allow for the presence of the cusp, and properly 
 beveled, as indicated. It should then be backed up with a single backing 
 of pure gold, about 34 gauge, which should be closely finished down to the 
 edges at all points, except on the occlusal, where a slight projecting surplus 
 should remain. 
 
 Facing and backing should now be placed in 
 0U$P$. position on the cap and sustained with hard wax 
 
 (Fig. 141 A), while the cusps are being formed and 
 fitted by whatever method selected. 
 
 These may be accurately obtained by allowing one or both of the pins 
 to project away from the backing, pouring soft plaster into the space 
 and up against them, and closing the articulator, and then subsequently 
 carving them and securing dies in the manner already outlined. The pins 
 are allowed to project as a means of securely sustaining the plaster during 
 the process. Or the cusps may be obtained from any of the die and die- 
 plate systems. 
 
 After swaging, the buccal portion of the gold 
 Hdaptation. should be cut away to the occlusal angle on a plane 
 
 which will admit of approximating it with the edge 
 of the facing and backing. This will leave only the thicknesses of the 
 gold forming the cusp and the backing along the occlusal edge, but the 
 same will afford ample protection to the porcelain, and admits of a more 
 esthetic result. 
 
 After thus trimming the cusp to adaptation with the porcelain the 
 two should be adjusted to the cap with wax and adapted to the articula- 
 tion and occlusion. (Fig. 141 B.) 
 
169 
 
 While all soldering may be done at the time of uniting cusp, facing 
 and cap, it is usually best to remove the cusp and facing in their proper 
 relation, and previously invest and attach them with a sufficient quantity 
 of 20 karat solder to efifect union and fill the lingual portion of the cusps. 
 
 To preclude the checking of the facing along the edge, as a result of 
 the impingement of the cusps occasioned by the shrinkage of the solder, 
 a slight space should be allowed between the backing and cusps, and this 
 filled with wax to prevent the investment material from running in. 
 
 When the parts are securely sustained with wax 
 Ht)PfOXiftial KWtorallon. enough should be further added to form the proper 
 approximal contour to secure a restoration of contact, 
 and a small piece of pure gold, about 36 gauge, should then be adapted 
 or burnished to each approximal side of the crown, extending from cusp 
 to cap, and held in place with the wax. This forms a matrix which facili- 
 tates soldering and gives the desired approximal contour, but should not 
 extend over the lingual portion of the wax, as the solder must be subse- 
 quently added from this point. 
 
 Foil gold. No. 60 or 120, may also be used for the same purpose, if 
 desired. 
 
 The crown should be invested with a slight 
 
 Tnocstitig. covering over and up to the edges of the pure gold 
 
 matrices to hold them in place, but with the lingual 
 
 surface freely exposed. When the investment has been properly trimmed, 
 
 the wax should be carefully picked out and the remainder removed by 
 
 pouring boiling water upon it, and the parts then fluxed and heated. 
 
 The soldering should be done by the consecutive 
 Soldering. application of small pieces of 18 karat solder, of a size 
 
 suitable to be readily dropped into the opening. Small 
 balls of scrap gold and silver are sometimes used to aid in filling in 
 when the space is of considerable size, and the use of the same facilitates 
 the procedure and lessens the extent of shrinkage which would take place 
 in the use of solder alone. The use of balls of German silver or copper 
 is also permissible if- they are well and completely covered over with 
 the gold solder. 
 
 In finishing, care should be exercised to preserve the approximal 
 contour, in order that contact may be properly restored and the crown 
 then poHshed and mounted. (Fig. 141 C.) 
 
 These crowns are sometimes constructed without cusps, but such 
 practice is to be condemned, except in rare instances on first bicuspids,, 
 because the usefulness of any crown is usually equal in importance to 
 cosmetic effect. 
 
I/O 
 
 a$c of Sadaic^Back Ceetb. 
 
 A variation of metiiod consists in employing- the so-called saddle- 
 back tooth instead of the facing, and while this style of construction pos- 
 sesses the advantage of presenting an occlusal surface of porcelain, and 
 thus avoiding any display of gold, the more esthetic result is probably 
 obtained at the expense of strength, as the thin lingual portion of such 
 porcelain teeth is usually inherently weak and more or less easily broken. 
 Where the stress of occlusion is light, however, they may often be used 
 to good advantage. 
 
 In their application a selection should be made 
 PfOCCdure, which possesses as broad a neck as will be required 
 
 to m-ake a perfect joint with the cap, and which will 
 restore the contact with adjacent teeth. 
 
 It should then be ground to meet these requirements, and to properly 
 occlude and articulate, after which a single backing of about 34 gauge 
 pure gold should be well adapted, attached by bending the pins, and 
 trimmed to closely follow the edges of the porcelain without overhanging. 
 (Fig. 142 A.) 
 
 The proper relation to the cap should now be obtained (Fig. 142 B) 
 and securely sustained with hard wax, and the crown invested in such 
 manner as to have the porcelain covered, but to leave the backing freely 
 exposed. 
 
 In soldering, a sufficient quantity of 18 karat solder (in addition to 
 the use of balls of metal, if desirable), to afford ample and adequate 
 contour of the approximal and lingual surfaces, should be used. Fig. 
 142 C illustrates the finished crown. 
 
 An ordinary vulcanite tooth may also be em- 
 
 Use Of UulCdllite ployed in similar manner, and in crowns of consider- 
 
 t<Ctb. able length sometimes to even better advantage, 
 
 because of possessing more strength in the lingual 
 
 cusp, due to the greater body of porcelain surrounding the pins. 
 
 In their use the heads of the pins should be compressed between the 
 beaks of pliers, or cut off, and the lingual surface ground smooth to 
 facilitate the adaptation of the backing and the above ])rocedure observed. 
 
171 
 Application or Remoi^able €rown$. 
 
 Previous to the modern methods of successfully treating chronic 
 alveolar abscesses, the construction of crowns which could be temporarily 
 removed from their attachment to the root and easily replaced was advo- 
 cated and practiced as a means of permitting; the necessary therapeutic 
 treatment of roots so affected. 
 
 At the present time, however, such practice, for this purpose, has 
 become almost, if not entirely, obsolete, and the application of such crowns 
 is, in consequence, indicated only in the construction of removable bridge- 
 zvork ; hence, their indications and usefulness, together with the various 
 methods of construction employed, will be subsequently considered. 
 
 jflpplicatioti to Trredularitles. 
 
 Since some cases and forms of irregularities are not always 
 amenable to the usual process of treatment for their correction, because 
 of the age of the patient, the poor character of the teeth, their position in 
 the arch, or other physiological or pathological reasons, it sometimes 
 becomes warrantable to sacrifice the natural crowns and effect artificial 
 substitution, which will relieve the disfigurement thus occasioned. 
 
 As the radical or injudicious destruction of the natural crowns of 
 teeth must be regarded as presenting a serious aspect, and particularly 
 when involving the anterior teeth, where they are necessarily sacrificed 
 to the gingival line, a careful study of the existing conditions must be 
 made, in order that it may be wisely determined that such a procedure 
 is justifiable. 
 
 The two general classes indicating such 
 
 Tit4iCiltiOJlS. treatment as a means of improving both useful- 
 
 ness and cosmetic effect, are those resulting from 
 malposition, and a diminution of the normal space caused by gravitation. 
 
 malposition. 
 
 Cases are not uncommon wherein the malposition of one or more 
 teeth, as previously indicated in Fig. 31, may be best corrected by the 
 application of artificial crowns, but the achievement of successfully artistic 
 and hygienic results in such instances will depend much upon a close 
 observation of the necessary details of construction. 
 
 In the construction of crowns for such 
 Construction. extreme cases, as is illustrated in Fig. 143, the cap and 
 
 dowel should be adapted to the root, as usual, and 
 -.the bite and impression taken and models secured. 
 
172 
 
 An extension from the cap which will afford 
 Extension fOf Support a close adaptation to the tissue, and a practically 
 
 Of facing. unyielding support to the facing when placed in its 
 
 proper position of alignment, should then be made by 
 burnishing a piece of pure gold, 34 to 36 gauge, to the model. 
 
 When the desired shape and conformation have been obtained, the 
 extension should then be imbedded into the model at least equal to its 
 thickness by first marking the outline and then uniformly scraping the 
 surface. 
 
 The cap should then be detached from the model and both cap and 
 extension again placed in position and their relation sustained with 
 hard wax. 
 
 The parts should now be removed and invested, and subsequently 
 united with adequate re-enforcement. This can be best accomplished by 
 trimming a piece of clasp metal or 22 karat plate, 28 to 30 gauge, of 
 
 proper size to rest upon the cap and cover the extension, and then uniting 
 the whole with 20 karat solder. 
 
 This should then be replaced in position on the model, and the crown 
 completed in the usual manner. 
 
 The hygienic qualities possessed by crowns so 
 l^ygicnic €on- constructed depend, of course, upon the adaptation of 
 Siderations. the extension and facing to the tissues upon which 
 
 they rest; but the burnishing (or swaging, if more 
 desirable) of the extension admits of a close conformation, and the 
 scraping of the surface of the model beneath it and the neck of the facing 
 so increases the bearing upon the tissue as to usually result in an adapta- 
 tion of the finished crown which will preclude the lodgment and accumula- 
 tion of debris. 
 
 Diminution of normal Space. 
 
 A condition which is a phase of malposition caused by the natural 
 tendency of teeth to gravitate toward an unoccupied space in the arch. 
 
is illustrated in Fig. 144, where, from the extensive destruction of the 
 natural crown by caries, the adjacent teeth have moved together, until 
 the space formerly existing in the normal relation is much reduced. 
 
 In such conditions, when involving any of the ten anterior teeth, the 
 application of an artificial crown of adequate and proportionate size would 
 be impossible, of course, unless sufficient accommodation be previously 
 gained by separating the teeth, and such a procedure is indicated, and 
 becomes essentially necessary, if the highest artistic results are to be 
 obtained. 
 
 In separating the teeth in such instances the 
 Separation of Cecfb. application of a simple regulating appliance may 
 become necessary if any great deal of space is to 
 be gained, and when the desired space has been obtained it may be pre- 
 served during the construction of the crown by wedging with a small 
 piece of wood, or by tightly packing with gutta percha or temporary stop- 
 ping during intervals between sittings. 
 
 Sufficient separation may often be secured in a more simple manner 
 by trimming and closely fitting a wedge of soft wood, previously com- 
 pressed in a small bench-vise, into the space. If the wood is properly 
 trimmed to follow the outlines of the adjacent teeth, so that it may be 
 worn with some degree of comfort, and then tightly fitted into the space, 
 having the surfaces approximating the adjacent teeth slightly concaved 
 to hold it in position, and the grain placed parallel with the long axis of 
 the tooth, the absorption of moisture will usually produce an expansion 
 sufficient to create the space desired. This may also be increased some- 
 what by the use of an intervening layer of cotton or tape when necessary. 
 
 Jlpplication of tDc Tntradcntal Band. 
 
 For the purpose of avoiding the necessary peripheral preparation of 
 the root and the possible irritating influence of a band, and at the same 
 time securing the additional stability afforded by the latter to the attach- 
 ment of a dowel crown, the intradcntal band has been devised. 
 
 The principle involved is similar to that of the original Biittner crown 
 in which the periphery of the root was trephined so as to form a seat 
 
174 
 
 for the accommodation of the band. In the appHcation of the uitradental 
 band, however, a groove is trephined into the root midway between 
 the pulp canal and the periphery, and a band subsequently fitted into 
 the groove. 
 
 The design was probably originally suggested and patented by Dr. 
 Moses Rynear, of New York, in 1886, but subsequent patents have been 
 obtained on modifications of this by Dr. J. Leon Williams, of London, 
 and Dr. B. J. Cigrand, of Chicago, in both of which the principle is the 
 same, but the application and details differ somewhat. 
 
 While the advantages claimed by the advocates for this mode of con- 
 struction are doubtless desirable, they are obtained at the expense of the 
 integrity of the basal portion of the root, and for this reason are indicated 
 only on large, strong roots, entirely free from decay, and will probably 
 never become more generally applicable. 
 
 /vy./4^. • Fixj.l46. 
 
 The design and method devised and employed 
 Ulilliams'S method, by Dr. Williams consists of a series of ready-made 
 platinum caps and dowels in graded sizes, together 
 with suitable trephines and root canal drills. 
 
 In the application of this style of crown the root 
 Jlpplication. is prepared as usual for a dowel crown, without a 
 
 band. A cap (Fig. 145 A) of suitable and propor- 
 tionate size is then selected from the series, and the trephine and drill of 
 corresponding size selected. 
 
 The canal is first enlarged with the drill (Fig. 145 B) to accommodate 
 the dowel, and the trephine then used to cut the groove for the reception 
 of the band, and the proper relation between the two is secured by the 
 guide post in the center of the trephine. (Fig. 145 C.) 
 
 When the cap has been thus closely adapted to the canal and groove. 
 
175 
 
 the surplus floor, which is about 34 to 36 gauge, should be trimmed to 
 follow the peripheral outline, and burnished to the desired adaptation with 
 the entire surface of the root. 
 
 The bite and impression should then be taken and the crown com- 
 pleted in the usual manner and mounted with cement. 
 
 The facility with which these ready-made caps may be secured and 
 adapted to the root in the use of this method expedites the detail of 
 construction, but the band seems too thin and narrow and the dowel 
 too slender to afTord adecjuate strength and stability to a crown of average 
 requirements. 
 
 The method devised by Dr. Cigrand constitutes 
 (KIgrand'S method, making the band and cap and adjusting the dowel, 
 and the necessary outfit consists of two sizes of 
 trephines and a measurement gauge, as previously illustrated in a consid- 
 eration of the treatment of "fractured roots." 
 
 In the application of this method the root is 
 
 Application. prepared as indicated, and the groove cut as deep as 
 
 practicable with the trephine of proportionate size. 
 The band is then cut the exact length indicated by the measurement guide 
 for the size trephine used, about one-eighth of an inch wide and of 30 
 gauge gold, 22 karat, or platinum, made in circular form, the edges 
 abutted, and soldered with a very small bit of solder. 
 
 It should then be fitted over the end of the measurement mandrel to 
 give it the proper form, and adjusted to position in the groove by gently 
 forcing to place. 
 
 The surplus end extending from the root should be allowed to remain 
 to facilitate removal and filed smooth on a parallel line with the surface 
 of the root. It should then be removed and soldered to a floor of pure 
 gold or platiimm, 34 gauge, somewhat larger than necessary, with a 
 minimum of solder. 
 
 The edge of the band previously fitted into the groove should now 
 be trimmed away until the fioor rests firmly against the root, when in 
 position, after which it should be trimmed and burnished to the proper 
 adaptation. 
 
 The canal should now be prepared, the dowel fitted, and then soldered 
 to the cap, as indicated, and the crown completed in the usual manner. 
 
 The completed crown and the relation it should bear to the root in 
 both of these methods is illustrated in Fig. 146. 
 
 Kcpairlnd ana Kemovlnd. 
 
 Because of the presence of porcelain, and the consequent more or 
 less frequent occurrence of fractured facings as a result of accident, in- 
 
1/6 
 
 adequate protection, or faulty articulation and occlusion, as well as for 
 the purpose of replacement or substitution, it often becomes necessary 
 to repair this style of crown, or to remove it from its attachment to the 
 root. 
 
 Kepairmg. 
 
 The presentation of fractured or broken facings on crowns and 
 bridges constitutes a large per cent of the failures requiring such atten- 
 tion, and where the work remains otherwise in good condition, and is 
 secure in its attachment, repair may be effected in an artistic manner bv 
 replacing the facings without removing the piece. 
 
 In the replacement of facings, several good and 
 
 Kcplacctnent of reliable methods are employed, but a selection of the 
 
 TacitlflS. best or most desirable one will depend much upon 
 
 the construction of the work and the requirements of 
 
 the case, as well as the individual preference of the operator. 
 
 When such a procedure is indicated, where the work has been con- 
 structed by the ordinary method, all remaining particles of porcelain sur- 
 rounding the pins should first be broken and removed. This can be quite 
 easily accomplished with excising forceps, cutting pliers or chisels, after 
 which the projecting pins should be cut away and ground down flush 
 and even with the surface of the backing, with a sharp, round, or oval, 
 plain, or plug-finishing bur. 
 
 The method usually and, perhaps, most com- 
 Uswal 111«tl)0d. monly employed consists of securing the attachment 
 of the replaced facing by simply bending or clinching 
 the pins upon the lingual surface of the backing. 
 
 In this procedure a facing of the required size, 
 
 Proc<dwr{. shape and color should be selected, and the backing 
 
 then properly perforated to admit of its adjustment. 
 
 The accurate position of the perforations may be easily ascertained, 
 
 and designated, by first coating the surface of the backing with a thin 
 
 film of melted wax, and then pressing the ends of the pins into it, after 
 
 noting that they have been made parallel zvith each other, and that the 
 
 facing is held in its proper relation to the backing and adjacent teeth or 
 
 facings. 
 
 When the exact location has been thus, or otherwise, designated, the 
 perforations may be made with a small spear-pointed drill, and subse- 
 quently enlarged to the proper proportions to receive the pins with a 
 round or fissure bur, or twist drill, of corresponding diameter. While 
 they should be large enough to readily admit of the reception of the pins, 
 
177 
 
 the fit should be sufficiently close to render the attachment secure, and 
 preclude the subsequent loosening of the facing. 
 
 The facing should be then adjusted to position and ground to fit 
 the backing, and to meet the requirements of length, occlusion and align- 
 ment ; and this may often be somewhat facilitated by bending the incisal 
 or occlusal edge of the backing, with pliers, until a more favorable shape 
 presents. 
 
 When the adaptation has been completed, it should be noted that the 
 pins extend through upon the lingual surface sufficiently far to admit of 
 securing a firm attachment by bending their surplus ends ; and in the 
 event of this being prevented by the thickness of the backing, its lingual 
 ■surface should be previously ground down with small carborundum 
 stones, or burs, until such security is made possible. 
 
 The surfaces of the facing and backing should then be thoroughly 
 cleaned, slightly roughened and dried with alcohol or chloroform, when 
 
 the backing should be covered with cement mixed fairly stiff, and the fac- 
 ing adjusted to position, where it should be held firmly while the ends 
 ■of the pins are being bent over upon the backing with pliers. 
 
 Moisture should then be excluded from the cement until it has thor- 
 oughly crystallized, when the edge of the backmg should be finished 
 down close to the porcelain, with disks, and the pins flattened with small 
 . stones until presentmg a more or less smooth and continuous contact with 
 the backing. The latter may usually be done to the best advantage, and 
 with the least danger of fracturing the cement, at a subsequent sitting. 
 
 Brewer's metbod. 
 
 The above procedure is much simplified and greatly facilitated by 
 the use of a pair of "riveting forceps," designed for the purpose of rivet- 
 ing the ends of the pins down close upon the backing, by Dr. Frank A. 
 Brewer, Sr., of King City, Cal. (Fig. 147.) 
 
178 
 
 One beak of these forceps presents a corrugated soft rubber pad, on? 
 an adjustable joint, which admits of its close adaptation to the facing, 
 at any angle or position, while the other presents a small concave steel 
 point, also likewise adjustable, which engages the end of the pin. 
 
 In the application of this method of attaching 
 
 Hppltcation. the facing, the perforations should be made and the 
 
 facing adapted, as indicated, and then the ends of 
 the pins or the backing should be sacrificed until the former project only 
 about 1/32 of an inch beyond the surface of the latter. 
 
 The lingual surface of the perforations should now be somewhat 
 countersunk with a round bur of proper size used in a right angle hand- 
 piece. 
 
 When the facing has been well adapted, it should be placed in posi- 
 tion with, or without, cement, and the forceps then adjusted, when a slight 
 pressure upon the handles applied during a rotary or swing- 
 ing movement of the arm will effect an expansion of the diameter, and a 
 compression of the heads of the pins, until a very secure and finished- 
 attachment results, with little or no danger of fracturing the porcelain.. 
 
 Underwooa's ana mitcbeirs mctbod. 
 
 The method advocated by Dr. C. J. Underwood, of Elgin, 111., which 
 in similar detail has also been employed for a number of years by Dr. 
 Wm. Mitchell, of London, England, is also valuable and useful, and is. 
 particularly applicable to those cases where the old backing was origin- 
 ally, or has been worn down until, too short to afirord the proper pro- 
 tection to the porcelain along the incisal or occlusal edge. 
 
 This method consists of adapting a duplicate backing to the lingual 
 surface of the old backing, and then attaching it to the pins of the facing 
 with solder, and, wherever the occlusion will admit, its application may 
 be made with very artistic results, and with a maximum of strnegth. 
 
 In the procedure incident to the application of 
 
 Jlpplication. this method, the remaining porcelain and project- 
 
 ing ends of the pins should be removed from the old 
 backing, and slots or grooves sufficiently wide to accommodate the pins 
 of the new facing and extending from the incisal or occlusal end toward 
 the cervical to a point which will admit of its proper adjustment, should 
 be made with a cross-cut or plain fissure bur. (Fig. 148 A.) 
 
 The location of these grooves may be accurately designated, as pre- 
 viously indicated, and the bur used should be of a diameter as similar tO' 
 that of the pins as possible. 
 
 The facing selected is then ground to the required and desired adap- 
 tation, and afterward backed up with pure gold, about 34 gauge. This. 
 
'79 
 
 should be well adapted to the incisal or occlusal end of the facing, and 
 trimmed to closely follow its outlines. The cervical edge of the backing 
 should be then drawn away from its contact with the porcelain toward 
 the extreme ends of the pins, so as to straddle or pass to the lingual sur- 
 face of the old backing. 
 
 Facing and backing should be then adjusted to position on the crown 
 or bridge, and the latter burnished to a close conformation with the lin- 
 gual surface of the old backing, which, if too thick to allow the pins to 
 project slightly through the new backing, should be ground until admit- 
 ting of same. (Fig. 148 B.) 
 
 While it is best to secure this adaptation directly in the mouth, it may 
 also be accomplished with reasonable accuracy by taking an impression 
 of the crown and adjacent teeth, after the grooves have been cut, with 
 gutta percha, and obtaining from it a fusible metal working model for 
 the purpose. 
 
 Fig. 1 48. 
 
 The adaptation should then be sustained by the use of wax or tem- 
 porary stopping, and the facing and backing gently detached, and in- 
 vested with sufficient care to insure the thorough penetration of the in- 
 vestmeni- material into the intervening space between the two. 
 
 The relation should now be permanently sustained by soldering the 
 backing to the exposed ends of the pins, and then re-enforcing it as much 
 as the occlusion will admit, after which it should be finished and polished 
 (Fig. 148 C.) and then mounted with cement. 
 
 While the detail of this method is necessarily somewhat circuitous, 
 the procedure afifords a most secure and finished result. 
 
 Dwidbfs method. 
 
 Dwight's method, which has been previously mentioned and illus- 
 trated in connection with replaceable and detachable facings, is also ap- 
 plicable to the repair of work where the ordinary two-pin facing has been 
 used. 
 
i8o 
 
 When the remaining porcelain and projecting 
 
 Jlpplication. ends of the pins have been removed, a facing of this 
 
 particular style should be selected and ground to 
 
 place, in which the procedure is facilitated because of the absence of any 
 
 pins. 
 
 After the proper adaptation h^s been secured, the "finder," which 
 is included among the necessary instruments for doing this special work, 
 and consists simply of a base or shank which fits into the socket in the fac- 
 ing, and tapers to a central point, should be adjusted to position. (Fig. 
 149 A.) 
 
 This affords a means of designating the exact location for a single 
 perforation in the old backing, by applying sufficient pressure, or by the 
 use of a thin film of wax, with the facing held in its proper relation. 
 
 F/Q.1^9, 
 
 A small perforation should first be made at this point with a drill or 
 round bur, and this then suitably enlarged with a twist drill, and subse- 
 quently threaded with a tap, both of which are also included in the outfit. 
 (Fig. 149 B.) 
 
 The threaded shank of the "attachment" should be now adjusted to 
 the "holder" (Fig. 149 C), and screwed into place until its base rests 
 firmly against the backing, and the spring ends are brought into proper 
 position to engage the facing. If the latter is impossible at the first trial, 
 the attachment should be unscrewed and removed, and the backing im- 
 mediately surrounding the perforation ground away. 
 
 By this means the threaded area may be gradually diminished 
 until the required relation is obtained, after securing which the projecting 
 end of the attachment upon the lingual surface is ground down even 
 with the backing, and the facing then mounted with cement. 
 
i8i 
 
 Bryant's method. 
 
 Among the most ingenious methods used in replacing facings is the 
 one devised by Dr. Emory A. Bryant, of Washington, D. C. This con- 
 sists of countersinking the old backing from the lingual surface; then 
 threading the pins of the facing, and attaching it to the backing by means 
 of a corresponding countersunk nut. 
 
 The latter are procurable in ready-made form, as are also the neces- 
 sary instruments for doing the work, and while this method affords a se- 
 cure means of attachment, the detail is somewhat exacting and requires 
 considerable time. 
 
 It is perhaps more generally applicable to replacing facings on bicus- 
 pids, or even molars, in bridgework, than to the anterior teeth, because 
 the strength of the attachment increases, of course, in proportion to the 
 thickness of the backing, which in this particular region is necessarily 
 governed by the occlusion, yet it may often be applied here. 
 
 Fic]. 150. 
 
 (t 
 
 In the application of this method, the remain- 
 Jfpplication. ing porcelain, and projecting ends of the pins, 
 
 should be removed, the new facing selected, and the 
 backing accurately perforated for the reception of the pins, as previously 
 indicated ; after which the facing should be ground to the required adap- 
 tation. 
 
 The perforations in the backing are now countersunk from the 
 lingual surface with the countersinking reamer in right angle handpiece, 
 until they are suitably enlarged to receive the small end of the nut and 
 admit of bringing it flush and even with the labial or buccal surface of 
 the backing (Fig. 150 A.), care being observed that it shall not protrude 
 to the least extent. 
 
 When this has been accomplished, the pins of the facing should be 
 threaded, first with the large size tool, or screw-plate, and finally with 
 the smaller one ; in this procedure care must be exercised to prevent 
 twisting off the pins. The use of a little oil will preclude this and facili- 
 tate the work. 
 
l82 
 
 The nuts are made of a well alloyed gold, corresponding in size with 
 the reamer, and are tapped to fit the threaded pins of the facing, to each 
 of which the respective nuts should be first adjusted to place, before the 
 permanent attachment of the facing to the backing is made. 
 
 The backing should then be coated with cement, the facing placed 
 in position and the nuts adjusted to the pins (Fig. 150 B) (which may be 
 facilitated by a "holder"), and alternately screwed to place with the 
 wrench, avoiding undue force, until both are firmly fixed in their proper 
 relation and the attachment is secure. 
 
 The projecting ends of the nuts and pins should now be ground 
 down, with small carborundum stones, until smooth and continuous with 
 the backing, and the surface subsequently polished with disks. (Fig. 
 150 C.) 
 
 The nuts, and a wrench, suitable for their adjustment, are illustrated 
 in Fig. 150 D. 
 
 The replacement of facings on bicuspids and 
 Kcplacins Bicuspid molars, although perhaps most generally confined to 
 on molar facings. bridgework, will be also considered in this connec- 
 tion. This is usually a somewhat more difficult 
 procedure, because of the increased thickness of the gold forming the 
 cusps and lingual contour, and surrounding the area where the attach- 
 ment must be secured, which usually precludes a projection of the ends 
 of the pins. 
 
 Where it may not be desirable to employ the Bryant method, or 
 where the same may seem contraindicated, or be impracticable, the most 
 simple and commonly applied procedure is to cut a countersunk aperture 
 in the old backing with drills and burs, of proportions suffici-ently large to 
 admit and accommodate both pins of an ordinary facing. 
 
 The facing should then be selected and ground to the required adap- 
 tation, and the ends of the pins bent somewhat diverging from each 
 other, or to present short sharp right angle turns, which may be passed 
 into the aperture when the facing is slightly inverted, and which will 
 hook over its edge upon bringing the facing into proper position. 
 
 This will increase the integrity and strength of the subsequent at- 
 tachment with cement, and the same may be further facilitated by serrat- 
 ing or roughening the surface of the backing with a sharp wheel or in- 
 verted cone bur. 
 
 Facing and backing should now^ be thoroughly dried, and the mount- 
 ing made with cement mixed fairly thick, and with an observation of the 
 previously mentioned details in this connection, reasonably permanent 
 results may be obtained. 
 
 Where adequate mechanical retention is possible, plastic amalgam 
 
i83 
 
 may often be used to good advantage, and is sometimes preferable to 
 cement. 
 
 In those cases where the old backing has been 
 
 Kcplaccmcnt of almost, or entirely, destroyed, so that sufficient oppor- 
 
 Tacing and Baching, tunity for securing adequate anchorage for a new 
 
 facing, by any of these methods, is doubtful ; or 
 
 where the cap and dowel have become detached from the root, or may 
 
 be removed without mutilation or destruction, repair can almost invariably 
 
 be best effected by cutting the remaining backing oil' close to the base of 
 
 the cap with a fine saw, excising forceps, carborundum stones or files, 
 
 and attaching the facing and its new backing by investing and soldering 
 
 in the usual manner. 
 
 The mechanical saw (Fig. 151) will usually be found best adapted 
 to such purpose, and is an indispensable device to a well-equiped labo- 
 ratorv. 
 
 Ficf. 151. 
 
 This procedure will afford opportunity for securing the strongest 
 and most artistic results wherever the adaptation between cap and root 
 is sufficiently good to warrant the use of tlie old cap, and where this is 
 doubtful, a new crown should be constructed throughout. 
 
 In such instances the procedure should consist 
 Procedure. in first removing the remaining cement from the in- 
 
 terior of the cap, with burs, and then thoroughly 
 cleansing in acid. The dowel should now be grasped firmly in a jeweler's 
 pin-vise (Fig. 152) (which is a most useful instrument in this work), 
 and the backing removed up sufficiently close to the base of the crown 
 to offer no obstruction to the proper adjustment of the facing. 
 
 The cap should be then placed in position upon the root, and the 
 usual "bite" and impression taken, when the repair can be made upon 
 the models in accordance with the usual method of construction from 
 this point on. 
 
i84 
 
 Rcttioving. 
 
 The removal of this style of crown may often become necessary for 
 the purpose of replacement or substitution, and while the procedure may 
 be found somewhat difficult in those cases where the attachment remains 
 secure, it may be effected by one or the other of the following methods : 
 
 Fiq.152. 
 
 Use of 
 excising Torccps. 
 
 The easiest and most convenient method, when- 
 ever applicable, is to first crush and remove the 
 facing if present, and then grasp the remaining^ 
 backing up close to the base of the crown, where 
 
 it is thickest, with the beaks of a pair of excising 
 
 forceps (Fig. 153) (which is also a most useful 
 
 instrument), and then gradually and slowly 
 
 fracture the cement and destroy the integrity 
 
 01 the attachment, by exerting a slight pressure 
 
 upon the handles and a lateral or rotary move- 
 ment upon the crown. 
 
 The power of the lever, in this application, 
 
 will usually result in the ready detachment of 
 
 the crown from the root, but force should be 
 
 applied slowly and with exteeme care, in order 
 
 to prevent injury to the peridental membrane, 
 
 or the removal of the root. 
 
 In the event of loosening the root, because 
 
 of its instability, or of the strength and integrity 
 
 of the attachment of the crown, tvhich will 
 
 alzvays cause a slight gingival hemorrhage, this 
 
 procedure should be at once discontinued before 
 
 injury has resulted, and another one requiring 
 
 less force will be demanded. 
 
 When the above method 
 seems contraindicated, or 
 proves ineffective, or where 
 
 the backing has been previously destroyed until no opportunity is afforded 
 
 for its application, the removal may be facilitated and made easy and 
 
 devoid of danger, by first separating the can from the dowel. 
 
 Separating 
 Cap and Dowel. 
 
 fiqJS3. 
 
i85 
 
 This may be done by drilling through the Ijase oi the crdw n at a point 
 approximating the periphery of the dozvel, until the root has Ijeen reached, 
 with a small drill or round bur, and then severing the cap from iIk- dowel 
 with burs of a larger size. 
 
 When this has been accomplished, if it is desirable to utilize the cap 
 again, it should be worked loose and lifted off with pliers ; but if no further 
 use is to be made of it, the procedure may be facilitated by destroying 
 the continuity of the band with excising or crown slitting forceps, or a 
 small bur. 
 
 The remaining dowel should then be removed by cutting away the 
 surrounding cement with very small round burs, until it may be gripped 
 with strong small-pointed pliers, and the entire length removed. 
 
 In this procedure, however, care must be exercised to avoid per- 
 forating the root, or breaking ofif the dowel at a point which will preclude 
 the removal . of the remaining end. 
 
 Jlccuracy in model makind. 
 
 Whilst much emphasis has already been placed upon the necessity for 
 accuracy in impression taking and model making, these features of the 
 procedure are of such paramount importance as to make special emphasis 
 warrantable. 
 
 Throughout the entire procedure incident to the construction, or even 
 the repair, of any style of crown, and particularly of those for the anterior 
 teeth, a good impression and an accurate model are prerequisites to suc- 
 cess, because by this means the work may be transferred from the mouth 
 to the laboratory with all the exactness which successful achievement 
 demands. 
 
 In order that the very best results may be obtained with the greatest 
 degree of accuracy and expediency, the impression should always be taken 
 in plaster because of its being the most reliable material ; and the model 
 obtained from it must support and sustain the cap — or caps — in the proper 
 and exact relation which, when in the mouth, they bear to the roots, to the 
 adjacent teeth, and to the gingival outline of the tissues. 
 
 The facility with which the cap, or caps, may be detached or removed 
 from the model — and in such manner as to admit of ready and accurate 
 readjustment — depends largely upon the observation of the detail of filling 
 the interior of the cap, and covering the dowel, with a thin film of melted 
 wax just previous to filling the impression, as is illustrated in Fig. 154 
 for a lateral and in Fig. 155 for a bicuspid crown. 
 
 This simple precaution readily admits of the easy detachment of the 
 cap from the model, and of its accurate subsequent replacement, both of 
 
t86 
 
 which remove any difficuUies or obstacles incident to the construction and 
 assemblage of the parts, and to the subsequent removal and investment of 
 the piece; and the preservation of the model thus made possible, affords 
 opportunity for final trials at any time during or after the completion of 
 the case, all of which are advantageous features. 
 
 Ficj./sa. 
 
 Fiq. IS5. 
 
 When the model has been separated from the impression, the cap may 
 then be easily removed by slightly warming the surplus end of the dowel 
 over a flame, and grasping it firmly with flat beak pliers, when a straight 
 pull will quickly detach it, and yet leave an outline of such accuracy as to 
 admit of its easy and correct readjustment to position. Fig. 156. 
 
 
 Fic/. 156. 
 
 Ficf.lSl, 
 
 After thus removing the cap the wax should be burned out, and it 
 should then be thoroughly cleaned in the acid bath to insure the further 
 removal of all residue from, and perfect cleanliness of, the metal, when 
 it may be placed upon the model, or laid aside for the time being, if prefer- 
 
I St 
 
 ahk', and the wax "l)itc" adjusted to jx-sition, l-i|^^ 157. and the case then 
 mounted u])on the articulator. 
 
 When more than one crown is bein^r constructed for the same mouth 
 at the same time, one model and "bite" is all that is necessary, but each 
 individual crown should always l)e separately invested and soldered. 
 
 \\ hile the ordinary crown articulator previously 
 TtnproPCd illustrated in Fig. 71 may be used, and will, of course, 
 
 Articulators. serve the jnirpose, better results from the view])oint 
 
 of a more accurate articulation, which is decidedly 
 advantageous ])articularly when porcelain is to be employed in anv man- 
 ner, may be obtained from the use of the more imj^roved. and so-called 
 anatomical, articulators, which are designed more especially for bridge- 
 work, and which admit of a slight forward, backward and lateral move- 
 ment. 
 
 Two designs j^osscssing these features which seem to be eminently 
 practical are Kerr"s Improved crown and l^ridge articulator, manufac- 
 tured by Mr. M. M. Kerr, of Detroit, Mich., and the design manufactured 
 by the Blue Island Specialty Co., of Blue Island. 111., each of which are 
 simple and inexpensive. 
 
ZM Plate and Dowel grown. 
 
 CHAPTER X. 
 
 Advantages. Indications, Requirements. Method of Construction; Typicall 
 Cases ; Root Preparation ; Six Anterior Teeth, Bicuspids. Adaptation 
 of Plate, Adjustment of Dowel. Extensive Destruction of Root: 
 Swaging Plate ; Impression of Root, Dies, Dowels. Con- 
 struction upon Models. 
 
 In view of the great variation of conditions presenting, and because 
 of the possible objections to a band which may be made with reason and 
 consistency in some instances, and in certain classes of cases; together 
 with the advantages to be derived from a close and more or less perfect 
 adaptation of the base of the crown to the end of the root, and the esthetic 
 possibilities afforded — the plate and dowel crown differing from the pre- 
 ceding style by the absence of a band, and consisting simply of a plate 
 and dowel base, has a wide range of application and usefulness, and is 
 somewhat extensively employed in the restoration of the ten anterior 
 teeth, and even sometimes on the molars. 
 
 When the employment of a band is contra- 
 
 JldVantad^S. indicated, or seemingly undesirable, such a style of 
 
 construction affords the advantage of securing a 
 closer line of junction between the crown and the root, by burnishing or 
 swaging a thin metal base and .then adjusting a dowel and completing 
 the crown in the usual manner, than cotild possibly result from grinding 
 one surface to conform closely with another, such as becomes necessary 
 in the application of the various forms of ready-made porcelain crowns. 
 
 While the esthetic possibilities thus afforded are also desirable, the 
 principal features lie in the conservation of tooth structure, the preserva- 
 tion of the normal condition of the gingivae, and the degree of perma- 
 nency that must result from obtaining a perfect joint betAveen the crown 
 and both the base and periphery of the root. 
 
 This style of construction is especially indicated 
 
 Tttdications. in two general classes of cases, and is applicable to a. 
 
 third, as follows : 
 
i8q 
 
 In pathological conditions where any extensive 
 TJrst: preparation of the remaining root, such as would 
 
 become necessary for a band, is precluded because 
 of its instability, or because of the physical or nervous condition of the 
 patient ; or, where a recession of the gum from the normal gingival line 
 would require the application of a crown without a band for esthetic 
 reasons. 
 
 Where the decay and destruction of the root is 
 Second: so extensive as to preclude the possibility of apply- 
 
 ing a band, — in which conditions, because of the ex- 
 treme shortness and consequent close proximity of the end of the root to 
 the border of the alveolus, no opportunity for securing an accurate adap- 
 tation of a band is afforded. 
 
 In this class of cases a crown may be constructed by sv/aging or 
 burnishing a base to a close conformation with the surface and irregular 
 edge of the root, with a degree of accuracy of adaptation, and support 
 to the root which will offer a secure and reasonably permanent attach- 
 ment. 
 
 It is also quite generally applicable and more or 
 
 tl)ird: less extensively employed in those typical cases where 
 
 the root is sufficiently large and strong, and free 
 
 from the evidences of caries or disintegration, as to probably require no 
 
 support and protection, such as the application of a band affords. 
 
 Also, it is particularly applicable and perhaps most often the desir- 
 able procedure, in restoring the crowns of partially developed teeth in 
 the mouths of young patients, because of thus avoiding any possible irri- 
 tation to the more or less susceptible, sensitive and highly organized tis- 
 sues in such cases. 
 
 The requirements of construction constitute se- 
 KequiretncntS. curing a preparation of the root, wherever sufficient 
 tooth structure remains, which will mechanically 
 prevent subsequent displacement of the crown, and of then securing adap- 
 tation of the base to both the surface and periphery of the root, which will 
 afford a firm seating, and, in so far as possible, preclude a dissolution 
 or disintegration of the cementing medium, or the subsequent occurrence 
 of caries. 
 
 While a close observation and fulfillment of these requirements will 
 doubtless make such a result possible, the degree of stability in the attach- 
 ment will, of course, depend much, if not entirely, upon the dowel ; which, 
 because of thus assuming a preponderance of the stress imposed, must be 
 properly adjusted to the canal, and of uniform and adequate 
 rigidity. 
 
190 
 
 mctDod of Construction. 
 
 As the method of construction for this style of crown differs only 
 in the details incident to the preparation of the root, and the adaptation 
 of the base, all reference to the application of the facing and the comple- 
 tion of the crown, whether for gold or porcelain work, will be purposely 
 avoided, because the procedure from this point on is identical with 
 that which is elsewhere considered in connection with each. 
 
 In the application of this style of crown to 
 
 tvpical 6a$($. typical cases, such as have been considered in the 
 
 first and third classes of indications, and which will 
 
 "be confined mostly to the six anterior teeth, the first essential feature in 
 
 the detail of construction is the proper preparation of the basal surface 
 
 of the root. 
 
 In this particular the requirements dift'er from 
 
 Root Preparation, those incident to the band and dowel crown, in that 
 
 110 periplicral triiiiiiiiiig is necessary, and that the end 
 
 of the root must be so shaped as to offer mechanical resistance to the stress 
 
 imposed. 
 
 In the six anterior teeth this may be accom- 
 
 $\K J\nUt\9r Ziith, plished by beveling the root both labially and lin- 
 
 gually from a central point, so that the plate, which 
 
 is to form the base of the crown, will straddle the exposed end, thus also 
 
 overcoming any tendency toward a possible rotation or displacement of 
 
 the crown. 
 
 The labial bevel should usually extend from tire lingual edge of the 
 pulp canal to a point sufficiently far beneath the gum to allow for the 
 thickness of the plate, and thus admit of placing the neck of the facing 
 in direct contact with the tissue, which adds to the esthetic effect by 
 making the joint invisible. 
 
 The lingual bevel should not extend quite to the gum line, because of 
 the absence of esthetic requirements upon this surface, and of the prob- 
 able advantage in having the joint exposed to view to insure the accuracy 
 of adaptation, and to the movements of the tongue and action of the secre- 
 tions, to render it more hygienic or self-cleansing. (Fig. 158a.) 
 
 This preparation may be. easily accomplished with flat-edge carbo- 
 rundum stones, though the use of the root facer will facilitate cutting the 
 root below the gum upon the labial surface. Wherever enamel is allowed 
 to remain, however, and no band is employed, this instrument must be 
 revolved slowly, and used with extreme care. 
 
 While a similar preparation is usually desirable 
 
 Bicuspids. for first bicuspids, because they are also subjected 
 
 to some lateral stress, it is not so essential to the 
 
T9I 
 
 second bicuspids, for the reason that these teeth usually receive vertical 
 stress mainly, hence a flat base, such as is indicated in Fig. 53, is all that 
 is necessary, if the size and adjustment of the dowel is adequate. 
 
 When the desired preparation has been secured, 
 Adaptation of Plat?, a piece of pure gold, or platinum, as the requirements 
 of the intended construction of the crown may in- 
 dicate, about 34 to 36 gauge, should be cut a trifle larger than necessary, 
 annealed, and burnished to a perfect adaptation VN'ith the surface of the 
 root. 
 
 This is easily accomplished with flat and round burnishers, and the 
 soft rubber tip of a lead pencil will also be found useful. While the thin- 
 ness and softness of either pure gold or platinum will admit of securing 
 the required adaptation by burnishing, the same may also be accomplished 
 by a primary swaging, if preferable, though the latter method is more 
 requisite in difficult cases, and will 1)e subsequently considered. 
 
 Fi(j.l58. 
 
 After securing the proper adaptation of the 
 JTdiUStment of Dowel, plate, the canal should then be prepared for the re- 
 ception of the dowel, and the latter fitted to it, when 
 the plate should be replaced in position and the opening of the canal out- 
 lined in it with a round or oval burnisher. (Fig. 158 b.) 
 
 The plate should now be perforated with a sharp-pointed instrument 
 or plate punch, and the dowel forced through the perforation until well 
 into position. While the close fit thus secured between plate and dowel 
 will usually sustain their relation while removing and soldering, if the 
 same is doubtful, the usual means for sustaining it, as previously de- 
 scribed, may be observed. 
 
 The two should now be permanently attached v/ith solder and then 
 again placed in position on the root and reburnished, when the surplus 
 may be trimmed away and the plate reinforced to prevent a possible 
 
192 
 
 change of form while taking the impression, and subsequently detaching 
 from the model. (Fig. 158 C.) 
 
 When the plate is of gold, this reinforcement should be made by flow- 
 ing a thin layer of 20 karat solder over the surface and around the dowel, 
 while if a platinum plate has been used, and a porcelain crown is to be 
 made, twenty-five per cent platinum solder, or pure gold, may be em- 
 ployed. 
 
 The usual "bite" and impression should now be taken and models 
 secured, when the facing should be selected and ground to a perfect joint 
 with the labial and cervical aspect of the plate, if it is to be backed up and 
 finished with gold (Fig. 158 d), and the crown then completed in the 
 usual manner, and finished and mounted. (Fig. 158 e.) 
 
 Extensive Destruction of Root. 
 
 In that class of cases where the root has been more or less extensively 
 destroyed from disintegration, or accident, and presents a concave sur- 
 
 a 
 
 Fic^. 159. c 
 
 h 
 
 face and frail and irregular edges so deeply imbedded beneath the gum 
 as to preclude the adaptation of a band, and yet possessing sufficient 
 stability and integrity to afford a reasonably firm attachment for a well- 
 adapted crown, as has been mentioned in the second class of indications, 
 the first essential procedure incident to the construction of the crown is 
 to tightly press away the surrounding soft tissue with temporary stopping, 
 or gutta percha, until a free exposure of the end of the root is obtained. 
 
 While this may require two or three sittings, repeating the proce- 
 dure at each, such time will be found to have been well expended, when 
 it is desirable to make an effort to successfully crown such teeth, because 
 •of thus making possible and facilitating the accurate adaptation of the 
 plate to the root, and the subsequent permanent attachment of the finished 
 crown. 
 
 When the root has been thus freely exposed, the irregular edges 
 should be ground down with small stones, or root facer, until as smooth 
 
193 
 
 and even as possible ; and all decay then removed, after which the re- 
 maining root should be thoroughly disinfected and sterilized, in order to 
 arrest any further progress of caries. 
 
 The best means of obtaining the correct adaptation of the plate to 
 the root will depend much upon the condition presenting, and while the 
 required conformation may often be obtained by burnishing, a more cer- 
 tain, and perhaps increased, accuracy will not infrequentlv be secured by 
 swaging. 
 
 To accomplish the swaging, whenever such 
 
 Swaging Plate. procedure may be indicated, or seem desirable, an 
 
 accurate and well-defined impression of the edge and 
 
 surface of the root must be taken, and fusible alloy dies m_ade therefrom. 
 
 The use of pink base-plate gutta percha affords 
 Impression of Roof, the most simple and accurate means of obtaining a 
 well-defined impression of the end of the root. 
 In the procedure this should be cut into moderately small pieces and 
 carefully and slowly warmed, on a mica slab over a flame, or on the elec- 
 tric annealer, until it is plastic, when a quantity sufficient to fill the spac^ 
 to be occupied by the crown should be tightly packed with burnishers 
 over and against the end of the root, and in between the adjacent teeth 
 if any be present. 
 
 Care should be observed to avoid over-heating or bu~ning the gutta 
 percha, as such accident entirely destroys its manipulative qualities. ^ 
 
 This should now be chilled with a spray of cold water, and removed 
 (Fig. 159 a), and when sufficiently accurate, fusible alloy dies mav be 
 obtained from it. ' ' 
 
 To obtain the dies, the impression should be in- 
 DIC$, vested, with the imprint of the root downward, in a 
 
 base of plaster of proportions sufficient to be subse- 
 quently trimmed to admit of the adjustment of the rubber casting ring 
 (Fig. 159 b). When the plaster has become thoroughlv crystallized, and 
 has been thus trimmed, it should be placed over a small'flame and allowed 
 to heat slowly until the gutta percha may be removed (Fig. 159 c), when 
 the rubber ring should be adjusted, and the die, and subsequently the 
 counter-die, secured with fusible alloy. 
 
 Pure gold or pure platinum, as the requirements may indicate of 
 the thickness of about 36 gauge, should be now annealed, and swaged 
 after which it may be further adapted to the root by burnishing, as al- 
 ready indicated, and the dowel, or dowels, then adjusted and soldered. 
 
 The length and size of the canal, or canals, in 
 
 Dowels such roots will indicate whether one or two dowels 
 
 should be used, and as they are generally much 
 
194 
 
 shorter than usual, and the major portion of the strength of the attach- 
 ment will depend upon the dowel, it is essential that it should be of ade- 
 quate size and length to thoroughly fill the canal; hence the use of two, 
 whether they may be separate from each other, or in contact and subse- 
 quently united with solder, is frequently required. 
 
 The relation between the plate and dowel, or dowels, should be tem- 
 porarily secured in the manner indicated, and then permanently sustained 
 by soldering, and wherever two dowels are used, and particularly when 
 they are separated, an investment should invariably be employed. 
 
 When they have been soldered, the cap should be placed upon the 
 root and the edge of the plate readapted by burnishing, in which the use 
 of a smooth foot plugger in the automatic mallet will often be found ad- 
 vantageous. 
 
 The usual "bite" and impression should be then taken and the crown 
 completed as the requirements may indicate, as illustrated in Fig. i6o. 
 
 While the interior of such roots is sometimes previously filled with 
 cement or amalgam, and the plate then adapted to this surface by burnish- 
 
 Ficj. 160. 
 
 ing, the increased accuracy obtained by swaging it to closely follow the 
 concaved surface of the root, and the additional support thus rendered to 
 the latter with a minimum quantity of cement, adds materially to the in- 
 tegrity of the attachment between the two, when subsequently mounted. 
 
 In instances where it may become necessary to 
 
 Construction construct the crown upon models, the most useful 
 
 Upon Models. and accurate reproduction of the conditions may be 
 secured by first fitting a wooden dowel into the canal 
 and then packing gutta percha over and around it, until the impression 
 of the end of the root has been obtained, as indicated. 
 
 When the desired degree of accuracy has been thus secured, it 
 should be placed in position, and a plaster impression then taken over it. 
 The removal of the latter will usually bring the gutta percha with it, but 
 if not, it should be detached from the root and placed in its proper posi- 
 tion in the impression. 
 
 When this has become thoroughly dry, the open ends may then be 
 closed up with mouldine, and the impression filled with fusible alloy. 
 
195 
 
 After separating from the plaster, and detaching the gutta percha 
 and wooden dowel, this procedure will result in a metal model with a 
 more or less perfect reproduction of the root and its canal, upon which 
 opportunity is afforded for the construction of the crown in the manner 
 indicated, and with reasonable accuracy. 
 
 [The application of this st}le of crown to the molar teeth is perhaps 
 confined more especially to porcelain work, but the same general princi- 
 ples should be observed irrespective of the style of construction.] 
 
Jfpplication «f Dowel erown$ mitbout Plate or Bind. 
 
 CHAPTER XL 
 
 Advantages ; Disadvantages ; Indications ; Requirements ; Various Designs ; Sep- 
 arable Dowels, Inseparable Dowels, Comparative Advantages. The Davis 
 Crown : Application, Mounting, Repairing, With Band and Cap ; Accu- 
 racy of Adaptation Without Band. The Logan Crown : Comparative 
 Advantages and Disadvantages ; Application ; Mounting. With Band 
 and Cap. Advantages ; Procedure. Variation of Methods : 
 Substituting Separate Dowel ; Procedure. Increased Ac- 
 curacy of Adaptation, Procedure. Porcelain Work. 
 The Brewster Crown : Application. The "Fellow- 
 ship" Crown : Application. Repairing. Tube 
 Crowns : Application ; Procedure. Tem- 
 porary Crowns : Indications ; Proced- 
 ure ; Use of Amalgam ; Use of 
 Vulcanite. 
 
 The various styles of ready-made porcelain crowns which are 
 designed to be adapted directly to the root, without the employment 
 of a band or plate, and attached by means of a dowel, which may be 
 either a separable or inseparable part of the crown, will, in regular 
 sequence, be designated and considered under this classification. 
 
 While almost any of the several designs of this particular style of 
 crown may be adapted with a band and cap, or even with a simple plate, 
 they are thus classified because of being usually employed without such 
 addition, and of being originally designed to be so adapted. 
 
 Although this particular style of crown preceded all others designed 
 especially for the anterior teeth, they are still used somewhat extensively, 
 and, irrespective of the improved means for obtaining greater integrity 
 and permanency, they doubtless possess some intrinsic advantages, and 
 still occupy a more or less limited sphere of usefulness and serviceability. 
 
 Previous to the individual construction of porce- 
 
 HdVtintagCS. Iain-faced crowns, the application of porcelain work, 
 
 and the present facilities for securing a more per- 
 fect adaptation to the root with equal opportunities for observing the 
 esthetic requirements, as indicated in the preceding chapter, the advan- 
 tages possessed by this style of crown were particularly desirable. 
 
 These constituted the ease with which the finished crown might be 
 procured ; the absence of the necessity for removing the enamel from 
 
197 
 
 the periphery of the root ; the facility and dispatch with which they might 
 be adapted, and the natural and translucent appearance which the splendid 
 forms and colors of some makes afforded. 
 
 While the latter is always an eminently desirable feature, particu- 
 larly in the restoration of the six anterior teeth, and gives to all porce- 
 lain crowns of any similar design a distinctive advantage over those in 
 which the translucency is destroyed by the presence of a backing, the 
 former should be so considered in the application of crowns designed 
 to serve as permanent reproductions, only when such are especially indi- 
 cated, and as a means of expediency. 
 
 The principal features which may be reason- 
 
 Disadvantaflts. ably regarded as disadvantages, when such crowns 
 are adapted without band or plate, lie in the diffi- 
 culty of obtaining a crown of the same diameter as the root, and of se- 
 curing a continuous and practically impervious joint between it and both 
 the base and periphery of the root, together with the resultant absence 
 of preventive means and prophylactic measures against the subsequent 
 dissolution or disintegration of the cementing medium from the pene- 
 tration of saliva, and the destruction of the root by caries or fracture. 
 
 As the result of a failure to observe the higher requirements in 
 this connection, many roots have been lost from caries, or fracture, which 
 might otherwise have possessed greater integrity and usefulness; and it is 
 by no means uncommon to see such crowns so displaced from the stress 
 of mastication, and the inherent weakness of the dowel, as to effect a 
 disarrangement of the alignment, and afiford a pocket between crown 
 and root which serves as a receptacle for the accumulation of the products 
 of decomposition. 
 
 In consequence of these possible disadvantages 
 
 Indications. the application of such crowns without a band or 
 
 plate, or without observing some means of securing 
 a more perfect and impervious joint than can usually be obtained by 
 grinding one surface to fit, and approximate with, another, is usually 
 indicated only in those cases where expediency renders such choice abso- 
 lutely necessary; or where, from the instability of the root, a recession of 
 the gum tissue, or other pathological conditions, or for pecuniary reasons 
 the application of a crown affording greater stability in the attachment, 
 or greater protection to the root, may not seem warrantable. 
 
 And even in such instances their application should usually be con- 
 fined to the six anterior teeth, because of the increased difficulty or- 
 dinarily encountered in adjusting them to the more or less irregular 
 shapes and uncertain canals of the bicuspids and molars. 
 
Conscientiously considered, such crowns must usually be regarded as 
 Icinporary work, in view of the reasonable opportunities for securing 
 greater permanency. 
 
 Kequiremetits. 
 
 In the application of any of the various designs now used, the same 
 esthetic requirements as indicated in the preceding chapter prevail, and 
 the possible permanency of the crowns will naturally increase in proportion 
 to the degree of accuracy obtained in adapting them to a close approx- 
 imation with both the base and peripheral outline of the root : and much 
 of the success attending such an adaptation will depend upon the proper 
 root preparation. 
 
 In the preparation of the root for the reception 
 Root Preparation. of such crowns, the removal of enamel, or peripheral 
 preparation of any kind, becomes entirely unneces- 
 sary, of course, but the shape given to the 1)asal surface should differ 
 
 Ficj.161. 
 
 from that indicated for the plate and dowel crown, because of the in- 
 creased difficulty of securing an adaptation to such a shape, hy grinding. 
 
 With the exception of the peripheral trimming, the preparation pre- 
 viously indicated in Fig. 50 will be found the most favorable to the re- 
 Cjuirements of the crown, and to the facility and accuracy with which the 
 adaptation may be secured. 
 
 This consists in grinding the labial edge just beneath the gingival 
 line, and in allowing the lingual to project slightly beyond it, with the 
 basal surface assuming a smooth inclined plane. (Fig. 161.) 
 
 The former admits of the advantages considered in this connection 
 in the preceding chapter, while the latter greatly facilitates the opportuni- 
 ties for securing the desired and required adaptation of the crown to 
 the root. 
 
199 
 
 Uarious De$idn$. 
 
 Although numerous designs of lliis style of crown have been pre- 
 sented from time to time, as previously recorded, only those which are 
 now manufactured in good variety, and which are more or less extensively 
 employed, will be considered. Jn their consideration it becomes necessary 
 to divide them into two classes, because of the variation in their con- 
 struction, and in the details incident to their respective application. Such 
 variation mainly depends upon the possession of separable or inseparahle 
 dowels, and causes them to be classified accordingly. 
 
 The feature of this class of crowns embraces a 
 
 Separable Dowels, separable or removable dowel, which may be i)revi- 
 
 ously mounted in the root, and to the projecting end 
 
 of which the crown may be subsequently attached. They are designed 
 
 for the purpose of facilitating the adaptation of the crown to the root, 
 
 and include the principles of the Davis crown. 
 
 This class of crowns embraces the feature 
 Inseparable Dowels, of an inseparable dowel, which is baked in or other- 
 wise securely attached to, the porcelain, and forms 
 an integral part of the crown, such as the Logan, Brewster and "Fellow- 
 ship" designs. 
 
 /r*^^*«,«„. While both of these stvles, and all of these re- 
 
 Gomparatipc .■ , . , , , 
 
 JIdfantafles. spective makes of crowns, are much used at the 
 
 present time, and either is capable of being more or 
 less readily adjusted to the root, a close study and analysis of the com- 
 parative advantages of the two classes must result in favor of those pos- 
 sessing a separable or removable dowel, providing, of course, that ade- 
 quate means are afforded for the subsequent attachment of the crown. 
 
 This is apparent, for the reason that the opportunities for securing 
 the closest possible adaptation, by grinding, are greatly facilitated by the 
 temporary absence of the dowel, as its presence must necessarily afford 
 some obstruction to this procedure, and at least increase the difficulties 
 attending it, together with the liability of weakening the dowel, l)y 
 grinding it, during the process. 
 
 Cbe Davis £rowti. 
 
 Of the several designs of crowns possessing separable dowels, the 
 Davis crown, suggested by Dr. Chas. H. Davis, and manufactured by 
 the Consolidated Dental ^danufacturing Co., is the only one which is 
 now employed to any extent, or which is made in a sufftcient variety of 
 moulds and colors to meet the requirements, and it has quite an exten- 
 sive application. 
 
 It is an all porcelain crown, having a slightly concaved base, 
 
200 
 
 in the center of which is a depressed rim, which affords a rest for the 
 shoulder on the dowel, and a countersunk cavity extending into the 
 crown sufficiently deep to accommodate the projecting end of the dowel. 
 
 The dowel is proportionate with the size of the crown ; slightly 
 tapered ; corrugated throughout its entire length to afford increased at- 
 tachment to the cementing medium ; has one flattened side to prevent the 
 possibility of rotation, and a shoulder which adapts itself to the depressed 
 rim for its accommodation in the crown, and is made of German silver 
 alloy for the purpose of obtaining greater inherent strength and rigidity 
 than is possessed by platinum. (Fig. 162.) 
 
 When the proper selection has been made, the 
 
 Jlpplication. primary rough grinding may be done upon the 
 
 model if the outline of the root is sufficiently 
 
 accurate, but the final adjustment to the desired adaptation should be 
 
 Fiq.l62. 
 
 Fiq.163. 
 
 made directly upon the root itself. This should be accomplished with 
 carborundum stones in the engine, and when sufficiently accurate the 
 ground surfaces, excepting the base, should be then nicely polished with 
 disks. 
 
 The canal should now be prepared for the reception of the dowel, 
 and the latter fitted closely to it; in some roots it may become necessary 
 to shorten it somewhat from the apical end. When thus primarily fitted, 
 it should be placed in position in the crown and temporarily sustained 
 with wax until the two may be adjusted to position on the root. (Fig. 
 163, A.) This may necessitate a slight enlargement of the basal portion 
 of the canal, or possibly the bending of the dowel, until the adjustment of 
 the crown to its proper relation with the root is obtained, after which 
 the crown and dowel may be permanently mounted. (Fig. 163, B.) 
 
201 
 
 In mounting, all particles of wax should be 
 
 mounting. thoroughly removed from the crown and dowel, and 
 
 the root rendered aseptic and dry, when the attach- 
 ment of the latter to both crown and root may be made simultaneously 
 with cement, or if it is preferable to use gutta percha, the dowel should 
 be first fixed in the crown with cement, and attachment to the root made 
 with gutta percha. 
 
 One of the most important advantages possessed 
 Repairing. by this style of crown is the ease and facility with 
 
 which repair may be effected in the event of subse- 
 quent fracture. 
 
 In such instances the dowel need not usually be disturbed, as its pro- 
 jecting end will afford ample opportunity for the retention of a new 
 crown, after the removal of the remaining cement, and the necessary 
 adaptation has been secured by grinding. These crowns may also often be 
 found applicable and useful in the repair of the Logan, and other styles 
 of crowns, where no backing is used, and the projecting end of the dowel 
 remains sufficiently long to afford adequate retention and resistance. 
 
 When it may seem desirable to employ the 
 iUitb Band and Cap. band and cap, in the adaptation of this crown, and 
 thus add to its possible permanency by supplying 
 means for the protection of the root, it may be accomplished with ease. 
 
 In their application in conjunction with band and cap, the root 
 should be prepared and the band fitted in exact accordance with the prin- 
 ciples previously outlined in connection with the band and dozvel croivn. 
 
 When the band has been thus fitted and trimmed to the proper width, 
 and the root ground down to evenly approximate its edge, as indicated in 
 Fig. 125, B, the crown should be selected and ground to a close confor- 
 mation with the basal surface of the root, as well as its peripheral outline. 
 
 The dowel should then be temporarily adjusted to the crown and 
 fitted to the canal, until the crown may assume its proper relation. A 
 plate of pure gold, 32 gauge, should now be perforated for the dowel, 
 placed in position on the crown, and trimmed to follow its outline, with 
 an allowance of about 1/32 of an inch surplus around the entire circum- 
 ference. 
 
 After annealing this plate, it should be again placed in position on 
 the crown, and both adjusted to the root, with the band in place. A de- 
 gree of accuracy in the adaptation of the plate to the root, crown, and 
 edge of the band may be obtained by placing a piece of soft wood against 
 the end of the crown, and gently tapping it with a mallet, and then hold- 
 ing firmly andi burnishing the surplus edge of the pure gold plate np 
 tight against the band. 
 
202 
 
 When this has been accompHshed, the crown should be removea, 
 and the pure gold plate placed in its proper relation to the band, which 
 has been made possible by the burnishing of this surplus edge, and the 
 two then united with 20 karat solder. 
 
 When the cap has been formed by the union of the band and plate, 
 and the surplus and excess edge finished down smooth with stones and 
 disks, it should be adjusted to position on the crown (to which the dowel 
 still remains temporarily attached) and securely united with wax. 
 
 The interior of the cap should now be filled with investment ma- 
 terial, or plaster, as indicated in Fig. 127, in order to securely sustain 
 their relation while soldering. After this has become sufficiently hard- 
 ened, the crown may be easily detached by slightly heating it over a flame 
 until the wax melts, when the dowel should be united to the cap by filling 
 in the space around the shoulder with 20 karat solder. 
 
 The cap may now be finished and polished, and then permanently 
 attached to the root, when the crown may be ])laced in posi- 
 
 Ficj . 164: 
 
 tion, and if too long, because of the thickness of the pure gold between 
 it and the root, the incisal end should be ground until the length is cor- 
 rect and the crown then subsequently mounted with cement. (Fig. 
 
 164.) 
 
 While the floor may be attached to the band in the ordinary man- 
 ner, without observing this detail, and the proper relation between the 
 parts subsequently secured, tnis procedure is warrantable and preferable 
 because of the accuracy and the conservation of tooth structure thus ob- 
 tained, as otherwise the canal may need to be much enlarged to admit of 
 placing the crown in its proper position and relation. 
 
 A method of securing a preservation of the 
 JlCCUracy of Jldaptation root, and a degree of accuracy in the adaptation of 
 
 UlitbOUt Band. these crowns, without a band or cap, which seems 
 quite practical and applicable to many cases, has 
 been suggested by Dr. J. R. Owens, of Cleveland, Ohio. 
 
203 
 
 In this method the basal end of the canal is enlarged as much as is 
 consistent with the strength of the remaining edge of the root, and then 
 somewhat countersunk. (Fig. 165, A.) 
 
 The crown is then adjusted to its proper adaptation by grinding, and 
 the dowel subsequently fitted until admitting of the correct adjustment 
 of the crown, when the dowel should be mounted in the constricted por- 
 tion of the canal with cement. 
 
 The surplus cement flowing into the countersunk cavity should be 
 removed and the latter then filled with amalgam. (Fig. 165, B.) While 
 this remains plastic, the crown should be placed in position and gently 
 forced to its proper adaptation with a piece of soft wood and small 
 mallet. The excess amalgam is then trimmed away, until a smooth joint 
 between crown and root remains, when the crown should be gently re- 
 moved and afterward permanently attached with cement. (Fig. 165, C.) 
 
 The advantages claimed for this method are the protection afforded 
 
 to the end of the root by the amalgam, and the accuracy of the adapta- 
 tion between crown and root which is facilitated by its manipulation while 
 in the plastic state. Its application, however, is necessarily confined to 
 good, strong roots, and while the How ''screw-post" is used by the 
 advocate, as illustrated, the dowel of the Davis crown will doubtless 
 answer as well. 
 
 Cbe Lmn £rown. 
 
 Of the various crowns with fixed, or inseparable dowels, the Logan 
 crown, originally designed by Dr. M. L. Logan, and manufactured by 
 the S. S. White Dental Mfg. Co., is, because of the almost unlimited 
 variety of splendid forms and colors in which it is made, probably the 
 most generally employed and universally adaptable. 
 
 The crown is made with a slight groove or depression in its base, 
 immediately surrounding the dowel, thus forming an elevated rim 
 around the edge which facilitates the adaptation, and, when not entirely 
 
204 
 
 obliterated by grinding, affords increased strength to the attachment by 
 . admitting of the presence of a greater quantity of the mounting material. 
 The dowel is of platinum and is baked into the body of the crown. 
 It is flattened and tapering in shape, and adjusted in the crown with the 
 greatest diameter placed labio and hucco-lingually, or in line with the 
 direction in which the greatest stress is usually imposed ; and a slight 
 corrugated depression in each side aids the attachment of the mounting 
 material. (Fig. i66.) 
 
 While this form of dowel is based upon theo- 
 ComparatiPC retically scientific principles, objectionable features 
 
 Jfdl)dntade$ and of some importance contra-indicate its too general 
 Di$adt)(inta9C$. application, and detract from its practicability. 
 These constitute the possible weakening of small 
 roots by the enlargement of their canals to the extent necessary to ac- 
 commodate the greatest diameter of the dowel ; the possibility of its 
 bending under the application of stress in the line of its smallest diameter, 
 and the inherent weakness of a platinwn dowel which is further an- 
 
 /vy. 166. 
 
 nealed to its softest form by being subjected to the high degree of heat 
 necessary to fuse the porcelain. 
 
 In many cases this required destruction of the root may leave it 
 so weakened as to be more or less easily fractured, if no band is em- 
 ployed, which is not an uncommon occurrence ; and the lack of rigidity 
 in the dowel, particularly in its lateral dimensions, affords opportunity 
 for it to bend under stress in this direction, and thus admit of the dis- 
 placement of the crown, which tendency or possibility may not always 
 be overcome by the close approximation of the crown to the adjacent 
 teeth. 
 
 In such cases, and especially where the latter is not possible, un- 
 less extreme care be taken, the employment of a crown possessing such 
 a dowel may be contraindicated, and the application of one with a more 
 round and rigid dowel may be found more serviceable. 
 
 In the application of the Logan crown the root 
 
 Jlpplicati^n. should be prepared, a model secured, and the selec- 
 
 tion made in accordance with the previously men- 
 tioned requirements for this general style of crown. 
 
205 
 
 A' more accurate selection of the crown for the individual case may 
 be greatly facilitated by preparing the canal after shaping the root, and 
 then adjusting a temporary dowel of wood or metal, allowing it to' pass 
 well into the canal and to extend down to, or near, the incisal end of 
 the adjacent teeth. (Fig. 167.) The end of an ordinary wooden tooth- 
 pick will answer this purpose nicely, and when so adjusted, a modeling 
 
 Ficj. 167. 
 
 compound impression should be taken with it in position. 
 
 In removing the impression, the temporary dowel should remain 
 firmly embedded in it, or be subsequently so placed, and the model made. 
 
 The removal of the dowel from the model will leave an outline of 
 the canal, and indicate its size, and position, in relation to the root, all 
 of which will be found decidedly convenient in, and advantageous to, 
 the selection of the crown, because of the facility with which it may be 
 readily adjusted to place. (Fig. 168.) 
 
 Ficj. 168. 
 
 While the final adaptation of the crown should always be made di- 
 rectly upon the root, the above procedure will be found additionally ad- 
 vantageous if the impression is taken in plaster, and, after drying thor- 
 oughly, then filled with fusible alloy. This affords an accurate and 
 comparatively indestructible model containing the outline of the base of 
 the root, and a reproduction of the canal ; and the crown may be selected, 
 
206 
 
 and primarily ground to a fairly accurate adjustment upon it, during the 
 absence of the patient. 
 
 The grinding to the proper adaptation should be accomplished with 
 small flat-edge carborundum, stones, in the engine, and care must be 
 observed to avoid cutting into the dowel, or weakening its attachment 
 to the porcelain. (Fig. 169.) The use of curved stones, suggested by 
 
 /yy . 169, 
 
 Mr. Robert Brewster, will be subsequently mentioned (Page 214) and 
 may be found useful. 
 
 In the final adaptation of the crown, the use of small disks of carbon 
 paper, perforated so as to slip over the dowel and rest against the base, 
 with the carbon side placed next to the porcelain, will be found service- 
 able in securing a close approximation. (Fig. 170.) 
 
 In the use of such disks, as the crown is pressed to place, the points 
 of contact between it and the root will be designated by a black mark 
 
 on the porcelain, and the grinding at such points should be continued 
 until the entire base thus indicates a uniform contact. 
 
 The requirements of peripheral approximation and occlusion should 
 now be observed with care not to destroy the integrity between crown 
 and dowel, and when the adaptation has been completed, any surfaces 
 of the porcelain which have been ground, excepting the base, should 
 be nicely smoothed and polished with disks, and the crown then 
 mounted. 
 
207 
 
 While many methods of mounting this style of 
 mounting. crown arc advocated, and the subject in general will 
 
 receive subsequent consideration, the permanency of 
 the attachment by any method will, of course, depend much upon the 
 accuracy of the adaptation. Where the joint is close enough to be ren- 
 dered practically impervious, either cement or gutta percha may be 
 used, as is the practice, and at the discretion of the operator. 
 
 The indications for the use of gutta percha increase, however, in 
 proportion to the inaccuracy of the adaptation, and the two materials 
 may be combined to advantage if desirable. In this procedure a disk 
 of the ordinary pink base-plate gutta percha should be cut a trifle larger 
 than the base of the crown, and then perforated to slip over the dowel. 
 The latter should now be slightly roughened with a sharp instrument, 
 and both it and the base of the crown then moistened with oil of cajaput 
 or any solvent, and the gutta percha disk adjusted to position. 
 
 It should then be placed on the electric gold annealer, or on a mica 
 
 slab,^ over a flame, and slowly heated until the gutta percha becomes 
 
 plastic, when, after moistening the root with water to prevent adhesion, 
 
 -the crown may be forced to place with enough pressure to mould the 
 
 gutta percha to it, and to the root, and to fill the intervening space. 
 
 While the crown is now held firmly in place, the surplus should be 
 trimmed away around the joint with a sharp, warm instrument, after 
 which it should be removed and again placed upon the heating apparatus, 
 until the root has been dried, and the base then moistened with the 
 solvent, when it may be mounted with cement in the ordinary manner. 
 A similar procedure is indicated in the use of gutta percha alone. 
 
 (Uitb Bana and eap. 
 
 Several methods of employing the Logan crown in combination with 
 a band and cap have been suggested as a means of obtaining greater 
 permanency in their application ; and when so adapted this or almost any 
 of the various forms of such crowns possesses advantages which place 
 them next in rank to porcelain work. 
 
 Such advantages constitute not only the in- 
 Mvmtum, creased integrity of the attachment, and preserva- 
 
 tion of the root, but include the esthetic possibilities 
 which may be obtained in the translucent and natural appearance af- 
 forded by an all porcelain crown devoid of the presence of any backing. 
 
 Of the several methods advocated for so adapt- 
 Proccaure. ing this style of crown, a modification of the one de- 
 
 vised by Dr. J. G. Hollingsworth will be found to be 
 the most generally applicable and universally practicable. 
 
208 
 
 • This consists in preparing the root as previously indicated in con- 
 nection with the "band and dowel" crown and the Davis crown with a 
 band, and in fitting the band and constructing the finished cap in the 
 same manner as prescribed for the former. 
 
 The crown should be selected in accordance with the details indi- 
 cated, and this may be observed either before or after the adjustment 
 of the cap. In grinding it to the proper adaptation, however, the cap 
 should be laid aside, and the adjustment made directly to the root, in 
 which procedure the original form of the base of the crown is entirely 
 changed, and it is only necessary to observe accuracy along the labial 
 edge. (Fig. 171, A.) 
 
 When a moderately accurate adaptation of this surface has been se- 
 cured, together with an observation of the remaining requirements, the 
 cap should be placed in position on the root, perforated to receive the 
 dowel, and the final adjustment then made zvith it in place. 
 
 When the required adaptation has been thus obtained, the base of 
 the crown should be further ground away on the lingual and approximal 
 edges until an adequate V-shaped space exists between this portion of it 
 and the cap. The space should be large enough to admit of being subse- 
 quently filled with solder, by which means the crown and cap are per- 
 manently attached, but should be no larger than necessary to facilitate 
 
209 
 
 this procedure, because of the possible weakening of the attachment of 
 the dowel in the porcelain. 
 
 The perforation of the cap should be made with care to have the 
 dowel at closely into it, as a preservation of the accurate relation be- 
 tween crown and cap, and the facility with which a strong union be- 
 tween them may be effected, will depend much upon such a relation. In 
 the event of making too large a perforation, an additional disk of thin 
 gold or platinum may be more accurately adjusted to the dowel, bur- 
 nished to place on the cap, and separately soldered in its proper position, 
 thus overcoming any possible difficulties in this connection. 
 
 The crown should now be backed up with a disk of platinum, about 
 36 gauge, which should be properly perforated, annealed, and closely 
 burnished to place. In trimming it to follow the outlines of the base of 
 the crown, a slight Ungual extension (Fig. 171, B) should be allowed to 
 remain, for the purpose of engaging in the investment material, and thus 
 retaining the backing in close proximity with the porcelain during the 
 process of soldering If this precaution is not observed, the backing 
 will invariably be drawn away from the base of the crown, as a result of 
 the shrinkage of the solder, thus diminishing the strength of the union, 
 and affording an unhygienic joint. 
 
 A backing of pure gold might also l)e used instead of platinum, but 
 the extreme thinness necessary to admit of carrying the porcelain well 
 up to the gingival line would only introduce the possibility of fusing it 
 during the process of filling this small space with solder. 
 
 When the backing has been adjusted, it sliould be attached in posi- 
 tion on the crown with melted adhesive wax (Fig. 171, C), and the re- 
 lation between crown and cap then secured on the root (Fig. 171, D), 
 with the same material. To accomplish this with accuracy and facility, 
 the cap should be placed in position on the root, kept perfectly dry, a little 
 adhesive wax melted on the backing around the dowel, and the crown 
 then quickly carried to place in its relation to the cap. 
 
 If the adhesive properties of the wax are not destroyed by the pres- 
 ence of moisture, and it is sufficiently heated to admit of the proper ad- 
 justment of the crown, the relation will be securely sustained, and crown 
 and cap may be safely detached from the root Avith a small pointed ex- 
 cavator passed around the edge of the band. 
 
 The remaining space in the joint should then be completely filled 
 with wax (Fig. 171, E), and the crown invested. Previous to investing, 
 the lingual extension of the backing should be bent over toward the 
 porcelain tvithout overlapping upon it, until it may be so engaged in the 
 investment material as to be held in place, yet offering no impediment 
 to the soldering. 
 
210 
 
 When the investment has crystaUized, it should be trimmed down 
 until as small as possible, to possess sufficient strength to hold the parts 
 together. The wax should now be removed, and the joint between cap 
 and backing then freely exposed, so as to admit of, and facilitate being 
 filled flush with solder (P"ig. 171, F.) The case should now be fluxed, 
 heated thoroughly, and the space then filled with 18 karat solder. 
 
 In soldering such crowns, it must be remembered that the porcelain 
 contains a large mass of platinum, hence it becomes necessary to first 
 heat the porcelain well, in order to prevent the occurrence of a fracture. 
 
 In filling the joint, the solder should be cut in small pieces, ami 
 each one of these consecutively applied and fused, to assure its pene- 
 tration to the full depth ; and a secure attachment to the dowel, which,, 
 being covered with investment material, and being most remote from 
 the exposed surfaces, is in consequence the most difficult to heat thor- 
 oughly. 
 
 This occasionally accounts for a failure to unite the crown to the cap, 
 arid in the event cf such an accident their union may be subsequently ef- 
 fected by again investing, leaving only the interior of the cap and the 
 dowel exposed, and attaching with a minimum of solder at the point of 
 junction between the two. 
 
 The contouring of the solder to a flush smooth surface may be some- 
 what facilitated by cutting small triangular pieces of platinum or gold 
 foil, or thin plate, and adapting them to the approximal sides of the wax. 
 in the joint, before investing, thus forming a matrix for the solder. 
 
 When the soldering has been completed and the cap becomes an in- 
 tegral part of the crown, it should be finished and polished as usual (Fig.. 
 171, G), and then mounted. 
 
 Uariation of lUctbods. 
 
 Several other methods of securing additional stability in the applica- 
 tion of such crowns are employed, and at least two of them miay often be 
 used to advantage. These consist in excising the original dozvel and 
 replacing it with a separate one; and in burnishing or szuaging a thin 
 plate to the basal end of the root and attaching it to the crown and' 
 dowel, as a means of securing a more perfect adaptation without the use 
 of a band. 
 
 Cases not infrequently present where it may be 
 Substituting difficult to secure a proper adjustment of a Hxed- 
 
 Separate Dowels. dowel crown, because of the constricted size, or un- 
 favorable location of the canal ; or the position or 
 shape of the root. In such instances the accomplishment of good results 
 with the use of this style of crown may occasionally indicate, or eveUx 
 
211 
 
 necessitate, the excision of the original dowel, and the employment of a 
 separate one. 
 
 When this procedure seems required, the cap 
 
 Procedure. should be constructed as usual, and an ordinary 
 
 platino-iridium dowel fitted to the canal and soldered 
 
 to it, allowing but a slier t projecting end to extend beyond the floor and 
 
 toward the porcelain, so as to ofifer no, or a minimum, obstruction to the 
 
 subsequent adjustment of the crown. 
 
 A suitable crown should be then selected and its dowel cut off at a 
 point about 1/16 of an inch from the base, when it may be ground to the 
 proper adaptation, as further indicated in the preceding method. It 
 should then be backed up in a similar manner, excepting that the backing 
 may be trimmed to follow the entire outline of the base of the crown, 
 and separately invested, so as to afiford a full exposure of the surface 
 of the backing (Fig. 172, A). When properly heated, this may be se- 
 curely attached to the short projecting end of the dowel witii solder. 
 
 The proper relation of the crown to the cap (Fig. 172, B) may now 
 be secured and sustained with adhesive wax, and the parts removed, in- 
 vested and soldered, as indicated. The finished crown is illustrated in 
 Fig. 172, C. 
 
 As the degree of strength obtained in the union of the crown with 
 the cap and dowel will depend much upon the length of the projecting 
 end of each dowel, and naturally increase in proportion thereto, this pro- 
 cedure should be confined to extreme cases, or to those wherein the 
 length of the crown may admit of a sufficient exposure of the ends of 
 the dowels to insure a degree of integrity in the finished crown. 
 
 A method of securing increased accuracy in 
 Increased JlCCUracv the adaptation of the crown to the root, which is 
 Of JIdaptation. applicable in many instances where it is not desir- 
 able to employ a band, was perhaps originally sug- 
 gested by Dr. Gordon White, of Nashville, Tenn. 
 
212 
 
 This consists in shaping the root, adapting the crown, and chang- 
 ing its original form, as previously described. 
 
 In the procedure incident to the employment of 
 Prcccdurc. this method, a disk of platinum foil, about No. 40 
 
 or 50, is annealed, perforated for the dowel, and 
 burnished to a close adaptation to the base of the crown, after the latter 
 has been properly ground, as indicated (Fig. 173, A). A second disk 
 is then cut somewhat larger than necessary, to cover the end of the root, 
 and closely adapted to it, thus forming a V-shaped space between the 
 two surfaces of metal which is subsequently filled with solder, in the 
 manner previously outlined. (Fig. 173, B.) 
 
 The first disk, which forms a backing for the crown, should have a 
 slight lingual extension for the purpose of sustaining its close proxim- 
 ity with the porcelain while soldering; and the second disk, which is 
 adapted to the base of the root, should possess a slight surplus on the 
 
 lingual surface, Vk^hich may be slit and burnished up over this portion of 
 the root, thus resulting in the additional support of a partial band. 
 
 In securing a proper and close adaptation of ea<^h to their respec- 
 tive positions, the first disk should be placed in position on the crown, 
 burnished, and trimmed, and then attached to the dowel with adhesive 
 wax. A sufficient quantity of the latter to a littlf more than fill the 
 space between crown and root should then be placer^ over this, and the 
 second disk adjusted to position on the wax and attached by touching 
 it with a hot instrument. The wax should then b^ chilled with cold 
 water, the crown and disks placed in position on the root, and force 
 enough applied with a piece of wood and small mallet to carry it well 
 to place, which will swage the second disk to a close conformation with 
 the base of the root, if enough wax is present. 
 
 The whole should then be removed and the surplus wax trimmed 
 down flush with the crown. The second disk may now be trimmed to 
 closely follow the outline of the root, excepting upon the lingual, which 
 
213 
 
 portion may be slit, as suggested, and burnished up over this surface of 
 the root upon the replacement of the crown. (F'ig. I74-) 
 
 When this has been accomplished, it should be removed, and in- 
 vested, and soldered, with an observation of the previously mentioned 
 requirements and precautions in this connection, and the finished crown 
 is illustrated in Fig. 173, C. 
 
 In roots possessing an irregular outline or concave base, this, or a 
 similar, procedure may be found advantageous ; and the disk which is 
 to be adapted to the root may be made of a heavier gauge of platinum 
 when indicated, or desirable, in the manner previously recommended in 
 connection with the "plate and dowel crozvn." 
 
 This procedure is also equally applicable to 
 
 Porcelain Ulork. porcelain work, and when porcelain is preferable to 
 
 the use of gold solder, for uniting the plate to the 
 
 crown, the details differ only in dispensing with the first disk, as this 
 
 Fiq.174, 
 
 Js used simply as a backing for the crown, and no backing becomes 
 necessary in porcelain work. 
 
 The adaptation of the disk to the base of the root, and the manner 
 of obtaining and sustaining its relation to both the crown and root, may 
 he accomplished as indicated, but the case should then be invested and 
 the disk permanently attached to the dowel with pure gold, or twenty- 
 five per cent platinum solder, before filling the intervening space with 
 porcelain, as a means of precluding any possible change of relation 
 which may accrue as a result of the shrinkage of the porcelain body in 
 fusing. 
 
 Cbc Brewster Crown. 
 
 Among the several other varieties of porcelain crown possessing 
 fixed dowels, the Brewster crown, designed and manufactured by IMr. 
 Robert Brewster, of Chicago, 111., is more or less extensively em- 
 ployed. 
 
 It is made of porcelain body, quite similar to Ash's English teeth, 
 in a good selection of moulds and colors, with a slightly concave base. 
 
214 
 
 and a round dowel. The latter is made of a composition metal similar 
 to the alloy of German silver, and is attached to the crown with a low- 
 fusing body. This enables it to possess the advantage of strength and 
 rigidity, as well as economy, and yet the attachment between crown and 
 dowel seems quite secure (Fig. 175, A). 
 
 The application of this crown may be made 
 
 Jlpplication. whenever the employment of a fixed dowel crown 
 
 is indicated, or desirable ; either with or without a 
 band or plate ; and the detail of procedure, in each instance, is identical 
 with that indicated for the Logan crown, excepting that the composi- 
 tion of the dowel and its manner of attachment in the porcelain pre- 
 clude its use in connection with porcelain work, where it is necessarily 
 subjected to a high degree of heat in the furnace ; though the same 
 readily admits of the use of 20 karat solder. 
 
 The favorable shape of both crown and dowel, and the comparative 
 ■ease with which it may be procured and adjusted, combined with its 
 
 a 
 
 ncf.l73, 
 
 inexpensiveness, make it very useful for temporary purposes; but when 
 employed as a permanent crown the dowel should be slightly flattened 
 on at least one side (or serrated), in order to facilitate the attachment 
 of the cementing medium, and thus prevent possible rotation or 
 loosening. 
 
 The adaptation of the base of the crown to the root may be accom- 
 plished with greater facility, and less danger of grinding the dowel, 
 by the use of curved carborundum wheels, which are designed and rec- 
 ommended by Mr. Brewster for this purpose. (Fig. 175, B.) 
 
 Cbe **Teiiow$bip" Crown, 
 
 The "Fellowship" crown, devised and manufactured by the Dental 
 Protective Supply Co., is constructed along lines similar to the pre- 
 ceding crown, and is also more or less extensively employed. 
 
 Any possible rotation of the crown on the dowel, or in its attach- 
 ment to the root, is prevented by the shape of the dowel, and the manner 
 in which it is attached to the porcelain. The shape, however, is similar 
 to that of the dowel of the Logan crown, and in consequence possesses 
 
215 
 
 the same objectionable features, it is made of a German-silver alloy, 
 and is attached in the crown by means of an additional piece of wire 
 passing laterally through perforations in the base of the crown and end 
 of the dowel, which are then subsequently filled flush with low-fusing 
 body. (Fig. 176.) 
 
 The details of procedure in the application of 
 HppliCfltiOn. this style of crown, and the indications for its em- 
 
 ployment are practically the same as those pre- 
 viously described. 
 
 Repairiiid. 
 
 In the event of the subsequent occurrence of a fracture of the porce- 
 lain in any of the various forms of fixed-dowel crowns, the method of 
 repair is often difficult and sometimes even impossible ; and the best 
 
 Fig. 176. 
 
 results are usually accomplished by removing the remaining dowel and 
 adapting a new crown. 
 
 When it has been mounted with cement, however, and particularly 
 in small constricted roots, this is often a difficult and sometimes dan- 
 gerous procedure ; but may be accomplished by drilling out the cement 
 immediately surrounding the dowel with a very small round bur until it 
 may be gradually loosened and removed, in which extreme care must 
 be exercised to prevent perforatmg the root or breaking ofit the dowel at 
 a point which will likely preclude the removal of its apical end. 
 
 In very small roots or where either of the latter results seem at all 
 probable, the method suggested by Dr. Joseph Head, of Philadelphia, 
 may be employed to advantage. This consists in cutting the dowel into 
 two lateral halves by drilling vertically through its smallest diameter 
 with a small round bur, and when so divided, the space thus produced 
 will admit of loosening each half until their separate removal may be 
 cfifected without danger of weakening the root. A pair of forceps 
 designed especially for this purpose by H. N. Lancaster may also be 
 found very useful. 
 
2l6 
 
 In those cases where the dowel remains firm in its attachment to 
 the root, and the length and strength of its projecting end will afford 
 adequate means of sustaining a new porcelain crown, it may often be left 
 in place and a Davis crown adapted to the root and then cemented to it; 
 or, a crown may be constructed possessing a socket in its base which will 
 fat and engage the projecting end of the dowel and securely sustain it 
 in its proper relation, when mounted with cement. As this latter pro- 
 cedure involves the construction of a crown which may often be found 
 useful and practical it will be separately considered under the classifi- 
 cation of tube croivns. 
 
 This style of crown is adaptable to that class of cases previously 
 referred to wherein the original has been broken away leaving the dowel 
 still firm in its attachment to the root ; and may be employed as a means 
 of substituting a well adapted crown when, for any reason, it may not 
 be deemed advisable, or desirable, to remove the remaining dowel. 
 
 The application of such a procedure and of the principles involved 
 was probably first suggested by Dr. Wm. Mitchell, of London, England, 
 but is also advocated and employed, as applied particularly to porcelain 
 work, by Dr. Jas. E. Keefe, of Chicago, 111., and Dr. F. J. Capon, of 
 Toronto, Canada. 
 
 "While the application of such crowns is neces- 
 
 Hppiication. sarily confined to repair work, they are equally ap- 
 
 plicable to cases where the original crown pos- 
 sessed a band and cap, which may or may not remain securely in place, 
 as well as to those where no band was used, so long as the dowel itself 
 remains ; but the strength in the attachment of the new crown will of 
 course depend upon the length of the end of the dowel exposed and 
 projecting beyond the surface of the cap, or root, which may be tele- 
 scoped by the tube. 
 
 When this is inadequate the opportunities for securing sufficient 
 integrity may be increased by drilling out the cement around the dowel, 
 and thus trephining its end, with a small round bur, until a greater 
 length is exposed ; but where a cap remains, unless the dowel projects 
 sufficiently far beyond it, such access and possibilities may indicate its 
 destruction and removal. 
 
 When the dowel has been thus exposed so as to insure sufficient 
 stability in the attachment of the crown, its end should be squared up 
 and properly shaped to admit of, and facilitate, the adaptation and 
 easy removal of a telescoping tube. (Fig. 177, A.) 
 
217 
 
 This tube should be made of pure gold or, plati- 
 
 Prcccdure. num, about 36 gauge, and may be formed on a.piec<j, 
 
 of wire previously selected for the purpose, and a. 
 
 trifle larger in diameter than the dowel ; or foil may be used and adapted 
 
 directly to the dowel, if subsequently reinforced with solder ; which 
 
 should be also observed even in the former. 
 
 When made and fitted, the joint should be soldered, and the tube 
 then adjusted to the dowel. A disk of pure gold or platinum, as the re- 
 quirements of the intended construction may indicate, about 36 gauge, ; 
 should now be perforated to fit closely over the tube, burnished to a 
 close adaptation to the root, and trimmed to follow its peripheral outline. 
 The surplus end of the tube should now be cut oflf even with the end of 
 the dowel, and the proper relation between it and the disk securely su.<;- 
 tained with adhesive wax, when they may be detached from the root and 
 invested and soldered, at which time the open end of the tube presenting 
 
 Fjq.177. 
 
 toward the incisal edge should be closed. This affords an accurately 
 adapted base for the subsequent construction of a crown in the ordinary 
 manner, using a facing in combination with either gold or porcelain, 
 which may then be finished and mounted with cement. 
 
 The completed crown for that class of cases where the end of the 
 dowel projects far enough beyond the base of the root to afford adequate 
 stability in the attachment is illustrated in Fig. 177, B; while the con- 
 struction for those cases wherein the end of the dowel is trephined and 
 the tube thus extended into the root, as a means of securing greater 
 integrity, is illustrated in Fig. 177, C, and the relation pf the, finished 
 crown to the root and dowel in the former class is illustrated in Fig. 
 177, 'D. ,. .. 
 
 Ccmporary €rown$. vi i 
 
 The employment of temporary crowns become necessary in emer- 
 gency cases where immediate substitution of the lost natural, c^r, b,i^o^e^ 
 artificial, crown is required; and is indicated in the construction oi per" 
 
2l8 
 
 manent crowns for the anterior teeth, for the purpose of relieving the 
 patient of temporary disfigurement and embarassment during the pro- 
 cedure. Their use also materially facilitates the subsequent adjustment 
 and mounting of the permanent crown by keeping the gum packed 
 away and preserving a free exposure of the end of the root, during the 
 interim. 
 
 Fic].l78, 
 
 In view of the possible advantages thus derived 
 Tndications. from their use in the application of dowel crowns, 
 
 ' ' and particularly in the mouths of women, they 
 
 should be invariably employed whenever the time required to complete 
 the construction of a permanent crown precludes finishing and mount- 
 ing the latter on the same day on which the root is prepared. 
 
 While almost any of the fixed-dowel crowns, and especially the less 
 expensive ones, will often answer this purpose, and even the old-style 
 English tube-teeth may be employed, the most simple, expeditious and 
 inexpensive method consists in using an ordinary long-pin facing, and 
 constructing the crown for the individual case. 
 
 FicjJ79. 
 
 To facilitate the application, at least a small 
 PfOCedure. selection of facings for the six anterior teeth should 
 
 be kept on hand. One suitable to the requirements 
 of the case in size, shape and color, should then be selected and ground 
 to a fairly good adaptation, and a dowel then made of German-silver 
 wire. Such wire is c-onvenient for many purposes and may be easily 
 procured in six-inch lengths of various sizes from jewelers' supply 
 houses. Fig. 178. 
 
219 
 
 A proper length and size of dowel should he cut, one end slightly 
 iapered with a file, and the other flattened with a small hammer on the 
 anvil, Fig. 179, or by pressing between rollers, Fig. 180, both of which 
 are useful appurtenances for the well equipped laboratory, until it 
 is broad enough to fit in snugly between the pins. This is done for the 
 purpose of facilitating the attachment of the facing, and preventing any 
 obstruction to the occlusion, but should not be done with a file, because 
 of thus unnecessarily diminishing the strength of the dowel at this 
 point. 
 
 The most convenient method of attaching the facing and dowel has 
 been suggested by Dr. W. H. Taggart, of Chicago, 111. In this pro- 
 
 r-icj.l80. 
 
 cedure the flattened end of the dowel is made somewhat broader than 
 the space between the pins of the facing, and then notched with the 
 edge of a file until it may be slipped into place, with the pins fitting 
 closely into the notches. The permanent relation between the two may 
 then be securely sustained by bending the pins over upon the dowel. 
 
 The dowel should now be bent, if necessary, until the crown may 
 be properly adjusted to position on the root, when it should be mounted 
 with temporary stopping or gutta percha, with which the desired con- 
 touring of the lingual surface can also be made. The consecutive steps 
 of this entire procedure are illustrated in Fig. 181. 
 
220 
 
 Temporary stopping may be used with greater facility and pos- 
 sesses sufficient integrity to serve the purpose for a few days, but when 
 the crown is to be worn for a longer, or more indefinite period, gutta 
 percha should be used. 
 
 Although the detail incident to the construction of such crowns 
 consumes but five or ten minutes' time, an assortment of these dowels 
 may be made at convenient opportunities, and kept for subsequent use,, 
 which will further expedite the work. 
 
 The relation between facing and dowel may be also sustained by the 
 use of either hard or soft solder, if desirable, but a more secure attach- 
 ment than is afforded by the above method is seldom, if ever, required. 
 
 In the use of gold or silver solder for such purposes the facing and 
 dowel should be attached by bending the pins, and the whole then in- 
 vested and soldered in the usual manner. In using soft solder, however, 
 no investment is necessary if the facing and dowel are placed upon a. 
 slightly heated charcoal or asbestos block or in a bed of asbestos fibre;. 
 
 I 1 1 
 
 the proper flux then applied, and evaporated with heat, and the solder then 
 fused by slowly directing the flame of a Bunsen burner or alcohol lamp 
 upon the facing. 
 
 A more artistic and finished contour of the 
 U$C Of JImalsam. Ungual surface, as well as a more permanent adapta- 
 tion of such crowns may be obtained by placing the 
 facing and dowel (after their attachment) upon the root, and packing 
 plastic amalgam over its end, and around the dowel, to the desired contour. 
 After this has crystallized, it may be finished and polished, and then 
 mounted. This procedure consumes more time, and entails more work 
 than is usually indicated or warrantable for temporary purposes. 
 
 More artistic and permanent results may also 
 Use Of Uulcanite. be obtained by adapting the base and- forming the 
 lingual contour with wax, and subsequently flask- 
 ing the crown and replacing the wax with vulcanite. In the process, 
 however, it becomes necessary to "tin" the German-silver dowel, so that, 
 the vulcanite may become attached to it, and the entire procedure re- 
 quires more time than that incident to the construction of a crown in a. 
 more practical and artistic manner. 
 
Jlpplicmion ana Construction of Porcelain Crowns. 
 
 CHAPTER XII. 
 
 Contraindications. Indications. Advantages : Esthetic ; Anterior Crowns, Bi- 
 cuspid Crowns, Molar Crowns. Hygienic. Mechanical ; Attachment of Facing, 
 Attachment of Molar and Bicuspid Crowns to Root. Application : Require- 
 ments ; Strength of Metal Construction, Soldering, Oxyhydrogen Flame, Root 
 Preparation. With Band and Dowel : Bands, Floor, Dowels, Accurate Fit- 
 ting Dowels, Impression and "Bite," Facing. Investment, Soldering Facing, 
 Anterior Crowns, Bicuspid Crowns, Molar Crowns ; With Facing, With- 
 out Facing. Variations in Construction : Re-enforced Caps ; Proced- 
 lu-e. Without Band; Procedure, Plate and Dowel. Partial Bands ; 
 Procedure. Jacket Crowns; Indications for Porcelain Jackets, 
 Procedure. Variation of Method. Use of the Davis and 
 Logan Crowns ; Advantages, Disadvantages. Application of 
 the Davis Crown, With Band, Without Band. 
 Application of the Logan Crown ; Procedure. 
 
 After having passed through the various experimental stages in- 
 cident to the development of its possibilities, the application of porcelain 
 v^rork, or the ceramic art has opened one of the most artistic and prac- 
 tical fields of dentistry, and is without doubt destined to become a perma- 
 nent part of modern practice. 
 
 While the primitive efforts in this line were fraught with many dis- 
 couraging phases, and replete with failures, and much of the resultant 
 development must be attributed to the ever-increasing and constantly im- 
 proving facilities ; yet, throughout the entire era of its employment, from 
 the time when the material was supplied in only one or two grades and 
 colors; when the coke furnaces afforded the only adequate means for 
 obtaining sufficient heat, and when the "baking" of a case required con- 
 siderable effort and consumed much time, until the present, when it can 
 
222 
 
 be procured in several grades and in varying colors ; when the same 
 procedure may be accomplished in the operating room in the presence of 
 the patient, instead of the laboratory, at night ; and at the expense of but 
 little time or effort, the possibilities of such work from an artistic point 
 of view have always been fully appreciated. 
 
 Since porcelain is a mineral substance, however, and in consequence 
 possesses the characteristic of friability, the possibilities from the view- 
 point of strength — which as a requirement is of equal importance with 
 the esthetic — have been observed and recognized only in its more modern 
 application ; and have been attained mainly as the result of continued 
 experimentation on the part of those who were sufficiently enthusiastic 
 and progressive to ascertain the causes of failures, and endeavor to over- 
 come them by the elimination of weak points. 
 
 As a result, the use of porcelain in its present form, and with the 
 facilities available, make it possible for the skilful and experienced ope- 
 rator to achieve results which combine both of these requirements to a: 
 high degree. This is especially true of its application to crown and 
 bridgework, in which its conservative employment may be productive of 
 a class of work which more closely approaches the ideal than any other,, 
 by conserving the very highest possible esthetic and mechanical require- 
 ments. 
 
 In view of the friable nature of porcelain, however, the desired and 
 necessary degree of strength is not to be obtained from thin layers, or 
 veneers, but is dependent upon the presence of a sufficient thickness tO' 
 insure the requisite resistance to stress. For this reason the possible 
 strength of such work will naturally increase in proportion to the quantity 
 which may be used in the individual case, or in proportion zvith the bulk; 
 and for the latter reason, porcelain work in any of its phases is not uni- 
 versally applicable, but, on the contrary, has its definite prescribed limita- 
 tions. 
 
 Hence the entire practicability of this class of work will depend upon,, 
 first, conservative or judicious application, and second, a skilful execution 
 of all of the details incident to the construction. 
 
 The absolute necessity for scrupulous attention to detail, and for the 
 utmost of painstaking care in its execution accounts to a large extent for 
 the occurrence of failures, and elevates this class of work to a plane some- 
 what beyond the ordinary. Indeed, the successful manipulation of porce- 
 lain promotes and demands the acquirement of a degree of skill, and the 
 cultivation of an artistic temperament, which is far beyond the province 
 of those whose efforts are more or less encompassed within the range of 
 indifference. 
 
 While failures will occur in any line of work, a very large proportion 
 
223 
 
 of them in this particular class can invariably be attributed to an inade- 
 quate conception of the requirements, or injudicious application; or to 
 unskilful or faulty construction and manipulation; either, or all, of which 
 should reflect upon the inexperience or indifference of the operator rather 
 than to cause or result in a premature condemnation of principles, methods 
 and materials involved. 
 
 Contraindications. 
 
 For these apparent reasons the application of porcelain.^© the con- 
 struction of individual croivns, to which consideration this chapter will 
 be exclusively devoted, is contraindicated in all cases where the maximum 
 length of the crown, or the close occlusion of the opposing teeth, precludes 
 the presence of porcelain in snificicnt thickness, or hulk, to insure an ade- 
 quate degree of strength; and where nothing but an indestructible sub-_ 
 stance, like metal, could be relied upon to withstand the stress of masti- 
 cation. 
 
 Indications. 
 
 As such cases present the exceptional, rather than the usual condi- 
 tions, however, and hence constitute a small percentage of those requiring 
 a restoration of the natural crown, the application of porcelain crowns, 
 properly constructed, is especially indicated on the ten anterior teeth, and 
 not infrequently ui^on the molars, in all cases which present ^n'&vm&i or 
 average favorable occlusion. ■-:■■■. ■ :■.■ ■■■■'x 
 
 The special advantages to be obtained from the application of porce- 
 lain ci;owns lie in the artistic manner and facility with which the natural 
 conditions and varying characteristics may be closely simulated ; the hygi- 
 enic qualities of the material, and the possibilities for comparative and 
 relative strength. These may be classified as esthetic, hygienic and me- 
 chanical and each will be separately considered. 
 
 While the possibilities for avoiding any dis- 
 €$tbctlc, play of gold are always very advantageous this 
 
 esthetic feature is further supplemented by the ab- 
 sence of a metal backing, the use of which particularly on the anterior 
 teeth is always more or less objectionable. 
 
 In the construction of crowns for the six an- 
 
 Jlnterior €rown$. terior teeth the reflection of the rays of light and 
 
 its variations bear materially upon the color problem, 
 
 and more artistic results are always to be obtained from the absence of 
 
 a metal backing for the reason that its presence destroys the transhicency 
 
 of the porcelain facino;; changes its color, and often occasions the appear- 
 
^24 
 
 arice 'Of a dark blue line along the point between facing- and backing. This 
 ktter unsightly and unhygienic condition is due to the penetration and 
 decomposition of secretions, and is of course decidedly objectionable. 
 While the translucency of the facing is slightly diminished even in a 
 porcelain crown, it is by no means destroyed^ and the other objectionable 
 features are entirely eliminated, all of which are, particularly in this 
 region, especially important considerations. 
 
 In the restoration of the crowns of bicuspids 
 " BlCtU^id Crowns. the employment of porcelain is especially indicated 
 ■r ' ,' because of the difficulty of obtaining the same 
 
 esthetic effect, combined with the required degree of strength, in any 
 'Ottie'r style of construction. Indeed the ease and facility with which 
 both of these features may be obtained, as compared with any other style 
 of crown, causes its application to be pre-eminently indicated on these 
 ieeth. 
 
 ^x, Although color and translucency are not sa 
 
 nidldf Crowns. essentially important a consideration in crowning the 
 molars, and granting the previously mentioned ad- 
 vantages of the gold shell or telescope crown for these teeth, there are 
 nevertheless frequent indications for the application of porcelain crowns. 
 Often on the first, and occasionally on the second molars, and particularly 
 in the mouths of women, gold crowns are more or less conspicuous, and 
 the use of porcelain may serve a highly esthetic purpose in these cases. 
 
 The hygienic properties of a smooth, highly 
 I)y0icniC. vitrified surface, like that which presents in porce- 
 
 - , lain, constitute an important advantage of inestim- 
 
 able Valiie in the mouth. Such a surface is more easily kept clean than 
 that of gold because it is immune to the chemical action of the secretions, 
 and food products will not cling to, become deposited upon, or be ab- 
 sorbed by it. For this reason, and possibly also because of its property of 
 slow conductivity, it is least irritating to, and most compatible with, the 
 tissues of the mouth. 
 
 Those advantages which have been classified 
 m^Cltanical. as mechanical will be considered from the view-point 
 
 of the relative degree of possible strength which 
 may be obtained both in the construction of the crown, and in its attach- 
 ment to the root. 
 
 As the attachment of the facing is usually the 
 
 JIttacbment of facing, weakest point in the construction of dowel crowns, 
 
 in this connection the relative strength to be obtained 
 
 from this style of construction as compared with a metal backed crown 
 
 is 'a matter of much concern and of appreciable importance. 
 
22,5 
 
 The probability of the subsequent occurrence of fractured facings 
 in porcelain crown work is reduced to a minimum for the reason that, 
 in a metal backed crown the facing is attached to the backing simply and 
 only by means of the attachment pins, while, in a porcelain crown, this 
 same attachment is also secured and then further supplemented by the 
 fusion of the porcelain over the entire lingual surface of the facing. 
 
 The additional strength thus obtained by this combined means of at- 
 tachment makes it practically impossible for the facing to be broken away 
 from a well constructed crown. When such breakage or accident does 
 occur, the entire mass of porcelain, including facing, will usually separate 
 from the cap, which rarely happens, and which can be quite as often 
 attributed to, and invariably indicates, faulty construction of the crown 
 with regard to the means observed for the support and retention of the 
 porcelain. 
 
 In the attachment of molar and bicuspid crowns 
 nttachmcnt of Ittolar to the root a possible mechanical advantage is also 
 and Bicuspid €rown$. possessed, even over gold crowns, because of the 
 greater facility with which a short projecting end 
 of the root may be properly prepared, and a narrow band accurately fitted, 
 as compared with the requirements incident to shaping a longer project- 
 ing end of the root and adapting a wider band. 
 
 While the latter procedure may be somewhat more difficult, any pos- 
 sible-advantage reverts, however, to the degree of skill with which the 
 detail is executed, and unless the esthetic requirements indicate the appli- 
 cation of a porcelain crown, or the root is primarily destroyed to a close 
 proximity with the gum line, the preference should usually be given to 
 the gold crown because of the conservation of tooth structure, and of the 
 increased strength in the attachment between crown and root which may 
 possibly be obtained in the use of a wider telescoping band. 
 
 In the application of this class of crown construction the highest pos- 
 sible advantages can be derived only from a careful observation of the 
 requirements, combined with a skilful execution of the details in the 
 preparation of the root ; the construction and adaptation of the cap, and 
 attachment of the facing; and the manipulation of the "body" itself. 
 
 When the conditions of occlusion are, or may be made, favorable, 
 and when these details of construction have been executed with skill, a 
 porcelain crown possesses adequate strength to meet the requirements 
 in all average and typical cases ; and the possible integrity in such work 
 often exceeds that of any other style of construction. 
 
226 
 
 To obtain such results with a maximum degree 
 
 KCQUircincnfS. of strength, however, three essential requirements 
 must be observed : First, the cap, or base, of the 
 crown must be inherently strong enough to retain its shape, and afford 
 ample means of attachment and support to the porcelain. Second, the 
 facing must be properly adapted, and securely attached to the cap; and 
 third,' the selection and manipulation of the "body" must be made with a 
 view to securing the best possible results. 
 
 In order that the requisite strength may exist 
 Strenstl) of metal in the metal parts they must be made of a material 
 
 Construction. which will withstand the degree of heat required tO' 
 
 fuse the porcelain ; and a gauge sufficiently thick tO' 
 retain its given shape must be used. Because of the practical infusibility 
 of platinum, of its malleability, slight susceptibility to oxidation, and tO' 
 the chemical action of the secretions, it is used almost exclusively for alt 
 of the parts for this work, excepting the dowel. For this purpose the 
 alloy of platinum and iridium is used because of the softness of platinum 
 alone, and of the additional stiffness imparted by the incorporation of 
 various proportions of the latter metal. 
 
 In soldering the various parts perfect contact 
 Soldering. between all joints to be united should exist, and their 
 
 union must be effected with a grade of solder which 
 will not be disturbed or re-fused in the subsequent "baking" of the crown. 
 For this reason 2y/r platinum solder should be used throughout the entire 
 assemblage of metal parts if the greatest degi'ee of strength is to be ob- 
 tained, and its use is absolutely nccessary"wheTk\^QV:€pnta.ct does not exist. 
 
 In the construction of single crowns, however, (all of the soldering 
 may be done successfully with the tise of pure gold as a solder, provided 
 that absolute contact of the parts has been secured, and that the gold ,is 
 then thoroughly fused until all surplus disappears by becoming absorbed 
 by, and alloyed zvith, the platinum. 
 
 This may be easily accomplished by the continued application of a 
 small pointed flame from the ordinary combination mouth blow-pipe, and 
 will be indicated by the disappearance of the surplus, and the blending 
 of its color into that of the platinum. To secure this result with facility, 
 however, it is highly important that only enough gold should be used to 
 make the joint, and such a union will possess strength, and successfully 
 withstand the degree of heat necessary to fuse the porcelain. 
 
 Should absolute contact not exist at any point in the joint the disap- 
 pearance of the pure gold solder, which may be due either to absorption 
 or to volatilization, will result in a subsequent opening and weakening of 
 the joint, either from the heat of the blow-pipe or furnace. 
 
22/ 
 
 Tn the use of platinum sulders. whether or not 
 
 Oxybydroaen TIame. an investment is employed, the use of the oxy- 
 
 hydrogen flame is expedient, and often abs(jlutel\ 
 
 essential, and while the same might also be used with, jnire gold, it is 
 
 entirely unnecessary. 
 
 As those requirements incident to the attachment of the facing, and 
 the manipulation of the body, constitute important procedures in the con- 
 struction of the crown, they will be c(jnsidered in regular order. 
 
 The requirements of root preparation are sim- 
 
 Koot Preparation. ilar to those previously indicated in the application 
 
 of any of the various styles of dowel crowns, with 
 
 the exception that, for porcelain work, the root should be cut down until 
 
 as short as consistent in order to secure as much space, and make as much 
 
 accommodation for the porcelain as possible. 
 
 While an unnecessary wast« or sacrifice of tooth structure is to be 
 condemned as a general practice, for the above reason the root should 
 be cut shorter for porcelain crowns than for any other style of construc- 
 tion, but, //■ (7 band is to be employed a projectiui^ surplus end should al- 
 ways be allowed to remain until the peripheral trimming has been accom- 
 plished, the measurement taken, and the band fitted. This is necessary 
 for the reasons previously mentioned in connection with the "band and 
 dowel" crown, and the same shape is indicated for the basal end of the 
 root as formerly recommended and illustrated for anterior roots in Fig. 
 50, and for bicuspid and molar roots in Fig. 53. 
 
 mitl) Band and Dowel. 
 
 As the employment of a band is generally conceded to be productive 
 of the most universally successful results, this style of construction will 
 be ^iven precedence in this consideration, and be followed by the varia- 
 tions, the indications for the application of each of which having been 
 previously mentioned. 
 
 The band should be made of platinum not 
 Bands. thicker than 28 nor thinner than 29 gauge, and the 
 
 edges should be slightly overlapped before solder- 
 ing. This method should be observed as a means of securing additional 
 strength, and of precluding the subsequent opening of the joint from 
 the expansion of the metal which is induced by the degree of heat neces- 
 sary to fuse the porcelain. The exact length of the measurement of the 
 root, taken in the ordinary manner, and cut and straightened as indi- 
 cated, should be designated by cutting a small nick in the edge of a piece 
 of platinum plate from which the band should then be cut about Vg of an 
 inch wide, and with an allowance of about i/i6of an inch surplus. (Fig. 
 
22^ 
 
 182A.) Each end should then be slightly beveled on one side with a 
 iile, and the band then annealed and made in circular form, with the sur- 
 plus end, designated by the nick, overlapping the outside of the other 
 end until the nick approximates evenly with this edge. (Fig. 182 B.) 
 
 The surplus overlapping end must be on the outside to prevent' 
 diminishing the size of the band, and the relation may then be sustained 
 by pinching the ends closely together with flat-nose pliers, which pro-' 
 duces a sharp angle on each side of the joint and affords a flat surface' 
 contact. (Fig. 182 C.) This will usually overcome a change in the re- 
 lation as the result of expansion when heated, though ■ a wire may be 
 twisted around the band for this purpose if necessary. 
 
 The joint should then be soldered with a mininium quantity of 25 
 per cent platinum solder, or with pure gold, to prevent unnecessary stiff- 
 ness, in the manner indicated. 
 
 The band should now be trimmed to follow the cervical curvature 
 of the gum, the edge nicely rounded, and then fitted to the root, and 
 afterward cut away until as narrozv as possible, in accordance with the 
 detail previously described. 
 
 The floor should be of about 32 gauge platinum 
 floor. cut somewhat larger than the diameter of the band. 
 
 The band should be placed in position on it, and 
 iirst simply tacked to place with a small quantity of solder. This primary 
 attachment secures the relation and anneals the floor metal so that it may 
 then be easily burnished into close and direct contact with the edge of 
 the band, without danger of changing the shape of the latter. 
 
 The soldering may now be completed in which, if pure gold is used, 
 it must be carefully noted that perfect contact exists around the entire 
 joint, alter which the surplus may be trimmed away and finished down 
 with file and disks until flush with the edge of the band. 
 
229 
 
 The dowel should be made of round iridio- 
 DOWelS. platinum zvi're of a size proportionate with the size 
 
 (;f the root and requirements of the crown, and fitted 
 to the canal in the manner previously outHned. 
 
 The cap should now be adjusted to place on the root, the floor 
 shghtly perforated for the dowel at the proper point, and this perfora- 
 tion then enlarged with the dowel by forcing it to place. This insures 
 a perfect contact between them which is essential to the strength of their 
 union, and to the facility with which it may be accomplished. 
 
 The relation should now be temporarily sustained with gutta-percha 
 or adhesive wax, until they may be removed, invested, and soldered as 
 indicated. While any means of investment is often unnecessary because 
 of the close relation thus existing, the simple means previously advo- 
 cated for this insures their proper relation. 
 
 Where it may be desirable to have the dowel 
 
 JlCCUrate Tiffing fit closely to the walls of the canal througfhout its 
 
 Dowels. entire length, the method suggested by Dr. A. O. 
 
 Hunt, and others may be used to advantage. This 
 
 consists in rolling platinum foil i-iooo into a cone, passing this cone 
 
 into the canal and expanding it first with a tapering pointed instrument, 
 
 and then by packing cotton into it, until it conforms to the shape of the 
 
 canal. It may now be removed and filled with platinum solder, and then 
 
 adjusted to its proper relation with the cap, as indicated. 
 
 The same procedure is also applicable to any kind of crown con- 
 struction, and for gold work the cone may be filled with scrap gold or 
 solder. 
 
 While iridio-platinum wire of a suitable size will usually meet all 
 of the requirements of a dowel, one constructed in this manner possesses 
 ■the advantage of being largest at the junction betzueen crozvn and roof 
 which is of course the weakest point in the attachment of any kind of a 
 dowel crown ;, and the use of such a dowel may be especially indicated 
 m those cases where the canal has become abnormally enlarged from decay. 
 
 When the cap has been completed and finished, 
 
 Tmpm$!on and adjusted to its proper position on the root, the 
 
 and "Blt«." usual impression should then be taken in plaster, 
 
 and this preceded, whenever necessary, by a "bite" 
 
 in wax. 
 
 After securing the impression, it should be observed that the cap 
 rests firmly in place in it, and, if necessary, it should be sealed with hot 
 wax. The interior of the band and surface of the dowel should then be 
 covered with a thin film of melted wax, to facilitate its removal from, 
 and admit of its accurate readjustment to, the model. 
 
230 
 
 This is of paramount importance in this class of work, because of 
 the necessity for frequently trying to place on the model during the con- 
 struction of the crown, and particularly in those cases requiring a resto- 
 ration of occlusion. 
 
 The facing should be selected in accordance 
 facing. with the requirements of color and size, and ground 
 
 to conform with the desired shape and character- 
 istics. As the color is more likely to be slightly bleached instead of be- 
 coming darker, if any variation is necessary or unavoidable, it should 
 invariably be darker than lighter, though the best makes of porcelain 
 teeth rarely change to any appreciable extent if the proper make and 
 color of "body" is placed back of them, and properly fused. 
 
 In this connection, it is necessary to use a "body" the fusing point 
 of which will not affect the color of the, facing, as an example of which 
 the use of the higher fusing American "bodies" in combination with the 
 English make of facings will entirely destroy the color of the latter. 
 
 a^ 
 
 c 
 
 cl 
 
 Fic]J&3. 
 
 In grinding the facing, the edge of the cap should previously be 
 nicely rounded with disks (Fig. 183, A), and the cervical end of the 
 facing then ground thin to admit of overlapping upon the labial or buccal 
 edge of the band without causing undue prominence at this point. (Fig. 
 183, B.) 
 
 This is necessary as a means of bringing the edge of the facing into 
 close proximity with the gum, and for the purpose of thus affording a 
 mechanical retention to the porcelain with which this portion of the band 
 should invariably be completely covered. 
 
 If the platinum band is not entirely covered upon this surface, it 
 will always show through the thin transparent tissue, and occasion the 
 presentation of a dark blue line, at this point. 
 
 As this is a decidedly inartistic and undesirahle feature, and as there 
 is no physical union hettveen porcelain and platinum, the overlapping of 
 the facing affords a secure mechanical retention for a sufficient quan- 
 tity of porcelain to cover this portion of the band and overcome this pos- 
 sible objection, and result in a smooth flush joint in the finished crown. 
 
231 
 
 Wherever it is desirable to retain porcelain in contact with platinum, 
 some similar means of affording mechanical retention is always neces- 
 sary, and this may be further facilitated by allowing a very slight space 
 to exist between facing and cap.- (Fig. 183,0.) 
 
 When the facing has been thus properly adapted, it should be sealed 
 to place on the cap with adhesive wax, and the whole then detached 
 from the model and inves<^ed. 
 
 In investing, only enough material should be 
 Tnoestment. used to surround the crown nicely and afford suffi- 
 
 cient strength in the investment ; and when the ma- 
 terial has crystallized, all surplus should be trimmed away until the 
 entire lingual surface of the facing is freely exposed. (Fig. 184.) 
 
 This free exposure is necessary as a means of facilitating the solder- 
 ing, and it may be made without increasing the danger of fracturing the 
 facing, if the case is then adequately heated before attempting to solder. 
 
 FicfJS^^ 
 
 Before heating the case the pins should he bent 
 Soldcrfnfl Taclng. dozvn tozvard the porcelain until their ends may be 
 brought into absolute contact with the metal parts. 
 This may be done by holding the facing firmly in place with a blunt- 
 pointed instrument in one hand, to prevent displacing it, while another 
 instrument, held in the other hand, may be placed against the extreme 
 ends of the pins and sufficient pressure applied to bend them into the 
 <lesired relation. 
 
 While it is always desirable to get the pins 
 interior Crowns. down dose to the facing, and thus make more room 
 for the porcelain, and still have an equal degree of 
 strength in their attachment, this is especially indicated in the construc- 
 tion of anterior crowns. 
 
 In th€se crowns the pins should be bent down close to the porce- 
 lain, and their ends brought into contact with the surplus end of the 
 
dowel at a point as close to the floor of the cap as possible (Fig. 185, A),. 
 or in direct contact with the floor itself. (Fig. 185, B.) 
 
 This is important, because it affords opportunities for the same de- 
 gree of strength in their union with the. cap, and yet adds to that of the 
 crown by getting the metal parts out of the way, so that they will not 
 divide the porcelain through the center, or interfere with the proper and 
 desired contour of the lingual surface. 
 
 In cases where the ends of the pins will not reach to the floor, or 
 dowel, the space between them and the floor, after being bent down to- 
 ward the porcelain, may be filled in with one or two thicknesses o£ 
 platinum plate, or wire, if necessary, until continuous contact may be 
 secured, as illustrated in Fig. 185, C. The finished crown, showing the 
 possibilities of contour, strength and artistic effect, is illustrated in Fig. 
 j85,D. 
 
 U 
 
 f/<f. 185. 
 
 As there is no physical union between porcelain 
 Bicuspid Crowns. and platinum, in the construction of bicuspid 
 crowns, it is not only desirable to make as much 
 spa^^eTor the porcelain which is to form the entire lingual surface of the 
 crown, as possible, but it is also often necessary to provide some means 
 for supporting it against any possible line of cleavage, in order to pre- 
 clude subsequent fracturing of this mass of porcelain from the stress of 
 mastication. 
 
 This support to the porcelain, and destruction of the line of cleav- 
 age, may be best and most easily accomplished by soldering a narrow 
 band of platinum to the floor of the cap, about one-sixteenth of an inch 
 inside of the edge of the band. This shoidd he fitted before heating the 
 case, and may be attached at the time of soldering the facing, and its pres- 
 ence thus forms a cup-shaped support which admirably answers the pur- 
 
pose for which it is intended, without showing^ through, or materially 
 weakening-, the porcelain. (Fig. i86. A.) ' >j , 
 
 Another means of accomplishing the same end has been suggested 
 by Dr. Capon, and consists in adapting and attaching a band around the 
 outside of the entire lingual surface of the cap, from one side of the fac- 
 ing to the other, and projecting about one-sixteenth of an inch beyond the 
 floor. (Fig. i86, B.) This method retains and supports the porcelain in 
 a splendid manner, but is much more difficult to adapt, and detracts some- 
 what from the artistic efifect obtained in the finislied crown. 
 
 The same result may also be obtained by attaching a small vertical 
 extension of round platinum wire to the immediate center of the lingual 
 portion of the cap. (Fig. i86, C.) Or, when two dowels are used, the 
 surplus end of the lingual one may be so employed. (Fig. i86, D.) 
 
 Unless in the latter instance this is somewhat difficult to hold in its 
 proper place while soldering, and may prove an element of weakness 
 
 IX. 
 
 c 
 
 Fi<j. 18 6. 
 
 d 
 
 instead of strength, if not properly adjusted. When this procedure is 
 observed in either instance the extension of wire should be in \}a^- exact 
 center, not project over one-sixteenth of an inch beyond the floor, and 
 the extreme end always well rounded. The finished crown is illustrated 
 in Fig. 1 86, E. 
 
 In the construction of molar crowns, two 
 niOlar 0rown$. methods are employed. One consists in using a "fac- 
 ing and observing similar details to those indicated 
 in the construction of bicuspids, and the other in making the cap, and 
 building the entire crown of porcelain without a facing. 
 
 While it is true that the requirements of color 
 
 Ulitb Tacing. are not quite so important in molars, the best results 
 
 will usually be obtained from the use of a facing 
 
 whenever possible, for the reason that both the form and color of the 
 
 visible parts of the crown are obtained and preserved in the facing. 
 
234 
 
 When a facing is used, the construction should be made, as indi- 
 cated for bicuspid crowns, and illustrated in Fig, 187, A, and Fig. 187, 
 B shows the finished crown. 
 
 In very close "bites" the use of a facing may 
 UlitbOtlt Tacing. often be contraindicated, and the best results ob- 
 tained by simply making the cap and forming the 
 entire crown with porcelain. For such cases the porcelain should be sup- 
 ported by any of the means indicated, the variations of which, together 
 with the finished crown, are illustrated in Fig. 188. 
 
 a 
 
 Fiq.187. 
 
 Additional mechanical means for obtaining, or aiding in, the attach- 
 ment of the porcelain to the cap may also be secured in any of these vari- 
 ous styles of construction, by roughening or spurring the surface of the 
 platinum with a sharp-pointed instrument. This latter method is em- 
 ployed exclusively by some, and may serve the purpose in large crowns, 
 
 F/q.l8d, 
 
 where considerable surface is exposed, without being supplemented by 
 any of the former means. 
 
 Uaridtions in Construction. 
 
 Because of the acknowledged advantages of a band, the foregoing" 
 style of construction has been given precedence, and designated as the 
 typical one; yet, while it is true that crowns so made are perhaps more 
 universally applicable, and productive of more permanent results, it is 
 also true that there are many variations of methods of more or less value, 
 the employment of many of which may be frequently indicated. 
 
235 
 
 Rccnforced €ap$. 
 
 As inherent strength in the metal parts has already been claimed as 
 a prerequisite in this work, one of the most useful variations in the con- 
 struction is to be obtained by reenforcing the cap in a manner similar to 
 that previously recommended in the construction of crowns with the so- 
 called saddle-back teeth. 
 
 Such a procedure imparts to the finished porcelain crown a degree 
 of strength which is appreciably valuable in many cases ; particularly in 
 bicuspid crowns, and in those cases where the crown is not supported by 
 adjacent teeth on one or both sides, and where the absence of some of 
 the opposing teeth necessitate more than average occluding stress. 
 
 This increased strength may be secured by allowing the floor to pro- 
 ject slightly beyond the band upon the approximal and lingual surfaces, 
 and then filling in the shoulder so formed with platinum solder until 
 smooth and flush. The additional thickness of a cap so made further pre- 
 
 cludes the possibility of subsequent irritation to the surrounding tissue by 
 afifording a heavier, smoother and more roimding edge. 
 
 In accomplishing this result, the procedure inci- 
 PfOCCdurc. dent to the fitting of the band and construction of 
 
 the cap is identical with that indicated in the preced- 
 ing method, except that platinum solder should be used. 
 
 When the floor has been attached to the band, the surplus should be 
 trimmed away until a projecting edge, from 1/16 to 1/32 of an inch, 
 remains upon the approximal and lingual surfaces. The labial or buccal 
 surface, however, must be trimmed flush and even with the band, in order 
 to prevent an undue prominence of the neck of the facing, and to admit 
 of properly overlapping it upon this surface of the band, both features 
 of which are illustrated in Fig. 189, A. 
 
 The slight shoulder so formed should be filled in with 25 per cent 
 platinum solder, until flush and even with the band, the edge then nicely 
 rounded and the dowel fitted and soldered as usual. (Fig. 189, B.) 
 
 The completed cap, with the proper relation of the facing, is shown 
 in Fig. 189, C, and the finished crown, with its apparent advantages, in 
 Fig. 189, D. 
 
236 ■ 
 Without Bana. 
 
 That style of construction which involves simply the adaptation of 
 a metal floor or base to the end of the root, and the attachment of a dOwel 
 and facing thereto, and which has previously been designated as the 
 -"plate and dowel" crown, is equally as applicable to porcelain work as 
 to gold work. 
 
 The indications and general principles, and the 
 PfOCCdurc. detail of procedure incident to the requirements of 
 
 root preparation, and the construction of the base 
 of the crown, are identically the same as previously outlined. The only 
 exception is the variation which the completion of the crown with porce- 
 lain "body" instead of gold solder demands, and which includes the use 
 of platinum and high-grade solder. 
 
 Fici. 190. 
 
 Wherever a band is not desirable, for any rea- 
 
 PlaU and Dowel. son, or where its use may be contraindicated, and the 
 
 preference given to this style of construction, a plate 
 
 of platinum about 36 gauge should be adapted to the end of the root, by 
 
 burnishing or swaging, as indicated in Chapter X. 
 
 The dowel should then be soldered; the cap again adjusted to the 
 root, and reburnished and properly trimmed around the edge, the models 
 secured, and the facing attached by observing the requirements indicated 
 in the immediately preceding style of construction, as are consecutively 
 illustrated in Fig. 190. If the presence of this thin plate of platinum 
 should be objectionable or conspicuous, it may be afterward removed 
 by destroying its attachment to the dowel with a small round bur, care- 
 fully inserting the edge of a thin knife blade between it and the porcelain 
 on the lingual surface, and gently lifting it away from the base of the 
 crown. A slight deepening of the canal, or shortening of the dowel, will 
 allow for its absence, and admit of placing the crown in close proximity 
 with the root. 
 
237 
 Partial Bands. 
 
 The employment of a partial ijand encircling only the approximal 
 and lingual sides of the root, as a means of increasing the stability of 
 the attachment of the crown, may also be made in a manner similar to 
 that already mentioned. 
 
 As this style of construction serves to fortify the crown against stress 
 in the direction in which it is usually imposed, and also renders this por- 
 ton of the joint between crown and root more or less immune to the 
 jjenetration of secretions, it at once recommends itself as a useful practice, 
 especially indicated on the six anterior teeth, where the root is allowed 
 to project slightly beyond the gum line on the lingual side. 
 
 /\ 
 
 Fi<jJ9L 
 
 The effect of a partial band to serve such pur- 
 
 Proccdwrc. poses ma}- be obtained with the greatest degree of 
 
 facility by allowing a sufficient surplus of the plate 
 
 to extend beyond the root on this surface, until the adaptation of ihe base 
 
 has been secured, and the dowel soldered. 
 
 The cap may now be adjusted to position on the root, where it is 
 held firmly by the presence of the dowel, and this surplus edge then bur- 
 nished up close to the surface of the root, and finally trimmed to follow 
 the curvature of the gum. 
 
 A surplus sufficient to admit of reaching the gum line, and passing 
 just a bit beneath it, should always be allowed to remain, and if the 
 accurate burnishing of this upturned edge is made difficult because of 
 the length of the root, a slight incision through the surplus edge of the 
 plate at the center of the lingual surface will facilitate the possible adapta- 
 tion. This may be subsequently soldered, either before or after the im- 
 pression has been taken, but should always be done before the porcelain 
 
238 
 
 is applied. More than one incision may be sometimes indicated, and are 
 permissible when necessar}^ 
 
 The various steps in this style of construction are consecutively illus- 
 trated in Fig. 191. 
 
 Jacket Crowns. 
 
 The principles involved in the so-called "jacket" style of crown con- 
 struction, as applied to both gold and porcelain work, have been else- 
 where considered, together with the indications, advantages and disad- 
 vantages governing their application. 
 
 The practicability of these crowns, however, when made in com- 
 bination with porcelain, is apparently a question of much dispute, and 
 has continued to be since the method, which was the primitive effort in 
 the line of constructing porcelain crowns in combination with platinum, 
 was first suggested by Dr. C. H. Land. 
 
 The advocates of this style of construction claim that it is more or 
 less universally indicated in restoring the crowns of the six anterior teeth, 
 upper and lower ; and that the principal advantage lies in the conservation 
 of tooth structure, and the preservation of the pulp. 
 
 While both of these considerations are always of material significance 
 to the conscientious operator, and should be observed wherever possible, 
 still they do not constitute the complete maximum of requirements of 
 crown construction and application, even when combined with the highest 
 esthetic possibilities, because the requirement of strength is, of course, 
 of equal importance, having so great an influence upon the serviceability 
 and permanency of the work. 
 
 In view of this fact, and also that the projecting end of the crown 
 of the natural tooth, which is to be telescoped by the cap or "jacket," as 
 a means of affording attachment for the artificial crown, is allowed to 
 remain, or is preserved, at the expense of the thickness of porcelain which 
 may be subsequently used in the construction of the crown ; and, because 
 of the friable nature of porcelain, particularly when used in small quan- 
 tity, this style of construction is not to be recommended as a general or 
 conservative practice, and is by no means universally applicable, if the 
 most permanent results are desired. 
 
 In this connection, it seems more than probable that a large per- 
 centage of the early failures which marked the advent of the porcelain 
 crown constructed for the individual case, and retarded the development 
 of this work, may be attributed as much to the method of construction as 
 to the use of the lozv fusing bodies, which were formerly employed. 
 
 Aside from the inherent weakness, which adequate accommodation 
 
239 
 
 for the root in the body of the crown demands, the artistic possibiHties 
 are also often somewhat hampered by the more or less clumsy appear- 
 ance of the finished crown. 
 
 Whenever on adequate length of the adjacent 
 Indications for teeth, and a favorable occlusion, will admit of over- 
 Porcdaln jackets, coming these objectionable features, and securing a 
 maximum degree of strength, jacket crowns may be 
 porcelain, producing serviceable and artistic 
 
 with 
 
 constructed 
 restorations. 
 
 In the application of this style of crown, the 
 Procedure. remaining natural crown should be favorably shaped 
 
 to admit of the accurate adaptation of the jacket, and 
 of the proper alignment of the facing, as indicated in the previous con- 
 sideration, and illustrated in Fig. 192, A. 
 
 « 
 
 The measurement should be taken and a band of about 36 gauge 
 platinum, wide enough to encompass the entire remaining natural crown, 
 then made. The overlapping of the ends in this instance is not always 
 advisable, because of the impediment offered to the burnishing by such 
 additional stiffness. 
 
 When this has been accurately trimmed and fitted at the cervical 
 edge, a cut in each approximal side of the band, beginning at the incisal 
 and extending well toward the cervical edge, will facilitate the subsequent 
 burnishing of the platinum into a close conformation with the root, A 
 blunt piece of wood and a light mallet, or a smooth foot-plugger in an 
 automatic mallet may be found useful in this procedure, but care should 
 be exercised to avoid drawing the cap down from its proper cervical 
 relation. 
 
 The edges should now be pinched together with pliers around the 
 incisal end of the root until in close contact, the cap then removed, the 
 surplus trimmed away, and the joints soldered. Pure gold will answer 
 
24P 
 
 nicely for this purpose, if used sparingly and properly fused, though plati- 
 num solder is preferable. 
 
 Platinum foil, No. 60 or 120, may often be used in securing the 
 proper adaptation around the cervix, and slightly beneath the free mar- 
 gin of the gum, to which point it should be carried, because of the greater 
 facility with which it may be even more closely adapted; and extreme 
 thinness of the cap, on the labial surface, at least, is also advantageous 
 to the subsequent adjustment of the facing. In the use of the foil, how- 
 ever, when the proper adaptation has been secured by burnishing, with 
 the surplus overlapped upon the approximal and lingual surfaces, the 
 cap should then be slightly re-inforced with platinum solder, or pure gold 
 thoroughly fused. 
 
 The best results are doubtless to be obtained, as a general practice, 
 from the use of the heavier cap, and while pure platinum is not as soft 
 and malleable as pure gold, if the piece is well annealed in the porcelain 
 furnace, as recommended, no great difficulty will be experienced in adapt- 
 ing platinum of 36 gauge to the requirements of these cases. If prefer- 
 able, the adaptation may be secured by taking an impression of the end 
 of the root, making dies and swaging, as previously described. 
 
 The entire surface of the cap, however made (Fig. 192, B), should 
 now be slightly roughened with a sharp chisel, or other convenient instru- 
 ment, to facilitate the attachment of the porcelain, and the impression 
 taken with it in position on the root. Before filling the impression, the 
 cap should be filled with wax to facilitate its subsequent removal from 
 the model. 
 
 A very thin facing (Fig. 192, C) of the proper size and color should 
 now be selected and ground to its proper adjustment. This sometimes 
 requires that the entire lingual surface, including pins, be ground away 
 until only a very thin veneer remains, but it is best to allow the pins to 
 remain also, if possible, because of the advantage to be derived from 
 their presence in securely sustaining the relation of the facing to the cap, 
 by bringing them in contact and soldering, previous to applying the por- 
 celain. (Fig. 192, D.) 
 
 Where it becomes necessary to grind the pins away entirely, the dif- 
 ficulty of sustaining the veneer in its relation to the cap during the appli- 
 cation and fusing of the "body" is, of course, increased, and extreme care 
 is necessary in heating the case, because of the possible expansion incident 
 to too rapid heating ; and in fusing, because of the shrinkage, each of 
 which may result in a displacement. 
 
 This procedure may be facilitated by first covering the cap with a 
 thin layer of "body" and fusing it until the particles are well coalesced, 
 without presenting a glazed surface. This then admits of a more ready 
 
241 
 
 and secure attachment of the veneer to the cap by holding it in place 
 and packing tliinly mixed liod>- into the space between it and the cap, 
 until it is retained in position by the adhesive properties of the bodv after 
 the moisture has been evaporated, when it is ready for the final attachment 
 to be obtained by the fusion of the porcelain. Fig. 192, E, illustrates the 
 finished crown. 
 
 A method of veneering platinum and gold 
 UarlatlOlt of method, crowns constructed in the ordinary manner, excepting 
 
 that tlic dimensions arc reduced enough to admit of 
 the presence of a covering of porcelain, which is retained in contact with 
 the metal by roughening the surface, is recommended by Dr. George Evans 
 .and others, as a means of securing the presentation" of a more esthetic 
 effect, combined with the advantages of a metal crown. 
 
 As thin layers of porcelain, whether of the high or low fusing variety 
 ■do not possess strength, and as there is no physieal or nwh-cidar union, 
 between porcelain and platinum, or gold, the method is not considered to 
 . be a safe or reliable one. 
 
 Where the jacket crown is to be employed in combination with porce- 
 1am, the strength of the body itself, and the integrity of the attachment 
 between it and the metal parts, both of which are essential to the dura- 
 bihty of the finished crown, will increase in proportion to the diminution 
 of the root, the quantity of porcelain thus accommodated, and the deo-ree 
 ot mechanical attachment for it, which is to be obtained bv rouo-henlno- 
 and serratmg all surfaces of the metal which are to be covered with tlie 
 "body." 
 
 On the other hand, it must, of course, be remembered that the de-ree 
 of integrity m the attachment of the finished crown to the root will increase 
 in proportion to the extent of tooth structure which is allowed to remain 
 and which may be telescoped by the cap. 
 
 Use Of m Hwii ana Eogan £rown$. 
 
 Ready-made porcelain crowns, such as the Davis and Logan designs, 
 may sometimes be employed to good advantage in porcelain work for the 
 six anterior teeth, by combining them with a a platinum plate or cap, as 
 a means of securing accuracy in their adaptation and permanency in their 
 attachment to the root. 
 
 The advantages to be obtained in the use of these 
 
 nmntms, crowns in this work lie in their artistic form, their 
 
 unexcelled strength, and the greater degree of trans- 
 
 ]ucency which the finished crown will possess, as a result of the absence 
 
242 
 
 of an additional layer of either metal or porcelain placed on the back of 
 the original crown. 
 
 While their artistic shape is not to be disputed, the experienced por- 
 celain worker, with a knowledge of tooth-form, will have no difficulty 
 in building the body to an equally artistic outline, where a facing is used, 
 so this feature is to be seriously regarded as a consideration only as a. 
 means of doing without the knowledge, and avoiding the small amount 
 of time and work thus involved. 
 
 The inherent strength of the porcelain of which these crowns are 
 made, which is obtained from the high fusing character of the "body,"" 
 and from its then being properly packed and fused, is doubtless greater 
 than the strength of the porcelain part of a crown constructed with a 
 facing. Hence, this feature must be regarded in the light of an advantage 
 of importance, and yet, where a simple facing is used, sufficient strength 
 may ordinarily be obtained by securely attaching it to the cap, using a 
 high-grade "body," and properly packing and fusing it. 
 
 The greater degree of translucency is indisputably true, and consti- 
 tutes an advantage of inestimable value in many cases, particularly where 
 the color is extremely difficult to match. While the texture of an ordinary 
 facing may be practically the same as that of these crowns, and it may 
 primarily possess the same degree of translucency, yet this important fea- 
 ture is, nevertheless, destroyed to some extent even by the presence of a 
 backing of porcelain, of nearly, if not quite, the same color. This is due 
 to the dividing line between, and the difference in the density of, the two 
 bodies. 
 
 These features of strength and translucency are so important as tO' 
 indicate the practicability and warrant the use of these crowns in many 
 cases, perhaps, in preference to any other style of construction, where a 
 good selection may be obtained. 
 
 The principal disadvantages lie in the fact that 
 
 Di$adO{intad($« one is confined to a more or less limited selection, and 
 that the opportunities are greater for securing a bet- 
 ter choice of facings than of crowns because of the latter being limited 
 to a few dozen moulds, as compared with the several hundred in which 
 the facings are made ; also the more intricate procedure, and greater length 
 of time consumed, in grinding the crown to a proper adjustment and rela- 
 tion as compared with the facing. 
 
 Because of the greater facility with which a 
 
 Jlpplication OT crown with a separate dowel may be adapted to the 
 the Davl$ Crown. root, the Davis crown will be found more generally 
 useful and applicable in this style of construction. 
 
 The accompanying dowel, however, is useless, and must be replaced 
 
243 
 
 witli one of iridio-platinum, because the so-called German silver alloys 
 will scarcely withstand the degree of heat necessary to subsequently fuse 
 the porcelain, and the latter will not become attached, or even fuse down 
 close, to these alloys. 
 
 In the application of this style of crown with 
 
 mith Band. a band, the root should be prepared, the cap made, 
 
 the dowel attached, and the impression taken, in exact 
 
 accordance with the requirements indicated for the "band and dowel" 
 
 style of construction with porcelain, at the beginning of this 
 
 chapter. 
 
 When the model has been secured, the cap should be detached there- 
 from, then replaced, and the crown selected. 
 
 The surplus end of the dowel should now be cut away until only 
 so much remains as will be accommodated by the depth of the countersunk 
 cavity in the crown, and the latter should be ground to the proper and 
 required adaptation with the cap and the adjacent and occluding teeth. 
 
 In this procedure the approximal sides should be ground so as to 
 admit of the overlapping of the labial and lingual edge of the crown upon 
 the cap. (Fig. 193, A.) This is essential for the purpose of bringing 
 the edges of the crown into close proximity with the gufti and of retaining 
 the porcelain which is to be subsequently applied to cover the band. 
 
 Owing to the shrinkage of porcelain, it is impossible to get enough 
 body between the crown and cap in the first or primary "bake" to com- 
 pletely fill the space. This would result in an element of weakness, of 
 course, in the finished crown, and may be overcome by further grinding 
 away the approximal surfaces of the crown, so as to afford opportunity 
 for the admission of a second application of "body," which may fill all 
 crevices caused by the shrinkage of the first. (Fig. 193, B.) 
 
 When the grinding of the crown has thus been completed, it should 
 be attached to the cap by filling the countersunk cavity in its body with 
 
244 
 
 thin, well mixed porcelain, and then gently forcing it to place while on 
 the model. The latter should now be gently tapped with an instrument 
 several times to pack the porcelain densely around the dowel, and in the 
 space, and it should then be allowed to dry until all of the moisture is 
 thoroughly evaporated. 
 
 The crown should now be gentl}^ removed from the model, adjusted 
 to a proper support, and given the primary "bake," and subsequently the 
 final one, in accordance with the requirements which will be considered 
 later. The completed crown is illustrated in Fig. 193, C. 
 
 When it is desirable to construct the crown by 
 
 mitbOUt Band. this method zvithoiit a band, the foregoing detail is 
 
 identical zvith the requirements, after the "plate and 
 
 dowel" have been properly adapted to the root and the impression taken 
 
 Ficj. 19^. 
 
 and model secured, which procedure has been previously considered in 
 its special application to porcelain work in this chapter. The various 
 steps in this style of construction are illustrated in Fig. 194. 
 
 Tlie Logan crown may be used in similar man- 
 Jlpplkation of ner, with either a band or simple plate, and the differ- 
 
 tbC Cogan €rown. ence in the procedure incident to its employment lies 
 in the absence of any necessity for using other than 
 the original dowel, which is of platinum and which constitutes an insepar- 
 able part of the crown. 
 
 ■ The presence of an inseparable dowel in this connection, however, 
 adds somewhat to the detail involved in grinding the crown to the required 
 adaptation with the cap or plate, and necessitates subjecting the porcelain 
 
^'45 
 
 to the heat of solderino; in attaching- it thereto, which, of course, is not true 
 in the use of tlie Davis crown. 
 
 In the application of this crown in comhination 
 Procedure. with porcelain and a platinum cap or plate, the same 
 
 detail as indicated in connection with the use of ^old 
 should be observed. 
 
 FJq. 195, 
 
 The base should be constructed of platinum of the same gauge as 
 for the Davis crown, and the temporary dowel should be adjusted, the 
 impression taken, and the model secured in accordance with the detail 
 previously outlined in the consideration of this style of crown in com- 
 bination with ofold. 
 
 />y. 196. 
 
 The crown should be then selected, ground as thus indicated (Fig. 
 195, A), attached to the base with a minute quantity of adhesive wax^ 
 removed from the model, invested, and the relation between the base and 
 dowel permanently sustained with a small quantity of pure gold, to pre- 
 clude any possible change which might result from the shrinkage of 
 Dorcelain. 
 
246 
 
 The soldering may be done with greater facility by covering the entire 
 crown with investment material, leaving only the surface of the base, 
 which comes in contact with the root and the dowel, exposed. ^Fig. 196.) 
 Considerable care must be exercised in this procedure, however, to prevent 
 fracturing the porcelain, which can only be avoided by thoroughly heating 
 the latter before attempting to solder. This space between base and crown 
 may then be filled with porcelain "body" and fused, and the finished crown 
 is illustrated in Fig. 195, B. 
 
Gomposition, ebaracteristics and manipulation 
 of Porcelain Bodies. 
 
 CHAPTER XIII. 
 
 Porcelain Compounds: Composition; Silica, Feldspar, Kaolin, "Flux," Col- 
 oring Matter. "High and Low" Fusing "Bodies" : Comparative Advantages. 
 Shrinkage, Fusing Points. "Gum Enamel" "Bodies." Requirements for 
 Crown and Bridgework. Manipulation of Body: Preparation of Crown, Se- 
 lection of Color. Mixmg "Bodj'," Applying and Building. One Grade of 
 "Body." Variations in Shading; Use of Oil Colors; Contouring and Carving. 
 Primary "Bake." Final "Bake." "Foundation" and "Enamel" "Bodies." 
 Precautions Incident to Fusing. Supporting Crown in Furnace. Placing Crown 
 in Furnace. Heating Furnace. Fusing: Tests, Porosity. Furnaces: Electric 
 Furnaces, Gasoline Furnaces, Gas Furnaces. 
 
 Porcelain Compounds. 
 
 With the rapid development of this class of work, a demand has 
 been created for the production of porcelain compounds which possess 
 qualities better suited to the requirements of manipulation and color than 
 was characteristic of those which were formerly used, and which had 
 been especially prepared for continuous gum work. 
 
 This latter grade of material, as originally compounded by Dr. John 
 Allen, and later by Dr. S. L. Close, in the absence of anything better, 
 was quite commonly used, and, when more finely pulverized to admit 
 of being carved and fused vv^ith greater accuracy, it served the pur- 
 pose so well as to be, to a great extent, responsible for the growth and 
 development of this class of work to the degree of its present successful 
 attainment. 
 
 As it was prepared in only one grade and color, however, the de- 
 
248 
 
 mands created by the possibilities of this work soon induced other man- 
 ufacturers to so alter and improve upon these materials as to furnish 
 compounds which would be somewhat less refractory, and which would 
 more nearly meet the requirements, with the result that several products 
 are now prepared in different grades and varying colors. 
 
 These various compounds are supplied in powder 
 Composition. form, and are known as "bodies," "enamels," and 
 
 "gum enamels." They are composed of silica, feld- 
 spar, kaolin and a suitable "flux," and are colored, or tinted, with metals 
 or metallic oxides. ^ 
 
 Silica is the dioJcide of silicon, a very refractory 
 Silica. and practically infusible substance found in the form 
 
 of agate and flint. It is the base of all true porce- 
 lain "bodies," and imparts structural strength to them. 
 
 Feldspar is a double silicate of aluminum and 
 Tddspaf. potassium. This material is somewhat less refrac- 
 
 tory than silica, and is incorporated for the purpose 
 of imparting stability to, and increasing the translucency of, the com- 
 pound. 
 
 Kaolin is the hydrated silicate of aluminum. 
 Kaolin. This is a very fine grade of clay, and is a most essen- 
 
 tial ingredient, being incorporated for the purpose 
 of imparting stability of form by holding the particles together, and thus 
 facilitating the moulding and carving of the mass into the desired shape. 
 
 The "flux" is usually composed of the carbon- 
 "TIUX." ates of the alkaline metals, sodium and potassium, 
 
 though in some classes of compounds the oxide of 
 lead is also much used. 
 
 The quantity and nature of the "flux," and the manner of its incor- 
 poration determines the fusibility of the former refractory ingredients, 
 and the tensile strength, or resistance :o fracture, of the mass when all 
 are fused together. 
 
 The coloring matter employed for the purpose 
 
 Colorins matter. of imparting the required variations of shade must 
 
 necessarily be more or less high fusing in character, 
 
 in order that the color, or tint, may not be dissipated, or burned out, in 
 
 the fusion of the compound. 
 
 While the coloring matter itself has practically no influence upon the 
 fusibility of the compound, the color imparted is, however, materially 
 affected by the degree of heat required. For this reason, metals, or me- 
 tallic oxides, are used for this purpose, in which the basal shades im- 
 parted are, approximately, as follows : 
 
249 
 
 Yellow, Titanium. 
 
 Brown, Iron. 
 
 Blue, Cobalt. 
 
 Gray, Platinum. 
 
 Pink (gum enamel), Silver and tin in combination with gold 
 
 (purple of cassius). 
 The colors and tints characteristic of the different "bodies" are pro- 
 duced by the use of these in various compounds, of equally varying pro- 
 portions, but the exact formula and methods of procedure are of special 
 interest to the manufacturers only, and are usually more or less care- 
 fully guarded by them. 
 
 '*l)lgb" and ''Eow" Tusing " Bodies." 
 
 The several varieties of "body" now prepared may be classified into 
 two distinct grades — the so-called "high" and "low" fusing, with the line 
 of common distinction between them being based, approximately, upon 
 the fusing point of pure gold. 
 
 An intelligent analysis of the comparative quali- 
 
 Comparative ties and advantages of the two classes of "body" 
 
 JIdPantases. demands a more or less limited familiarity with the 
 
 composition of these compounds, and with the 
 
 characteristics of their respective ingredients. 
 
 Silica being the most refractory and infusible substance, it might be 
 commonly supposed that a "body" capable of being fused at a lower 
 temperature than another would necessarily contain less of this ingre- 
 dient and more feldspar and kaolin in proportion. 
 
 Such an assumption would be correct if the "flux" played a less con- 
 spicuous part in the reduction, but the same relative formula of the three 
 basal ingredients may be used, and yet the fusing point of the resulting 
 compound be regulated by the proportion of "flux" subsequently added 
 to this formula. 
 
 But as a "body" must possess sufficient inherent strength, integrity 
 and stability to offer a high degree of resistance to fracture, and must 
 possess translucency, and absence of opaqueness, an adequate proportion 
 of these three basal ingredients seems essentially necessary, since each 
 has its place and purposes in the compound, as previously indicated. 
 
 This being apparent, if the fusing point is then regulated or con- 
 trolled by the proportion of "flux," and it is conceded that the latter does 
 not impart to the compound the highest degree of strength possible, in 
 the light of our present knowledge it seems reasonable to deduce that, 
 when a sufficient proportion of "flux" to reduce the fusing point of these 
 refractory materials below a certain point is incorporated, the maximum 
 degree of strength possible is not imparted to, nor obtained in, the product. 
 
250 
 
 It, therefore, seems evident that when a maximum degree of 
 strength is to be obtained, such as is required in the construction of 
 crowns, or bridges, where at best the friable material is to assume the 
 full stress of mastication, by direct contact, the compound which will best 
 serve the purpose must be one possessing the integrity and stability im- 
 parted by the three basal ingredients to a degree not entirely destroyed 
 by the incorporation of too great a proportion of "flux." 
 
 All porcelain compounds shrink in fusing in 
 Shrinkage. proportion to the degree of their fineness of tex- 
 
 ture, and the quantity and nature of the "flux" used ; 
 and the degree of shrinkage adds to the difficulties incident to their man- 
 ipulation with certainty, accuracy and expediency. 
 
 The "high" fusing compounds shrink from ten to fifteen per cent, 
 while the "low" fusing range from the latter point up to 25 per cent, 
 and some of the glass or extremely low fusing "bodies" which contain 
 lead in large proportions even greatly exceed this. There is never any 
 indication for the use of the latter, however, because of their minimum 
 strength, and of their invariable tendency to discolor in the mouth, which 
 may be attributed to the presence of the lead. 
 
 All of the compounds are more or less porous, and hence trans- 
 lucent, in proportion to the degree of fineness to which they are pulver- 
 ized before fusing. Hence, as the lower fusing "bodies" are always re- 
 duced to a much finer texture in their preparation, they possess a greater 
 density of structure. 
 
 This increased density, however, is due to the more homogeneous 
 coalescence of the particles as a result of the more thorough admixture 
 of the "flux," and is gained at the expense of translucency and stability, 
 since the "flux," beyond a certain proportion, does not add integrity to the 
 mass, but, on the contrary, increases the shrinkage, friability and tendency 
 to globulate in fusing. 
 
 The degree of shrinkage is a very objectionable feature in this work, 
 where so large a quantity of body is used, because the resistance to the 
 contraction which takes place in the lower fusing "bodies," and which 
 resistance is ofifered by contact with facing and cap, induces a tendency 
 to fracture which greatly diminishes the strength. 
 
 A summary of the apparent disadvantages to be found in the "low" 
 fusing "bodies" thus consists in their degree of contraction; their dimin- 
 ished strength and translucency, and their lack of stability of form and 
 color. 
 
 These features also make their manipulation with accuracy and cer- 
 tainty more difficult, particularly for the inexperienced, because of the 
 necessity for shutting off the heat at the precise degree at which the 
 
proper fusing point is reached, in order to avoid a dissipation of the 
 color, and a loss of the desired form, as a result of their great tendency 
 to become spherical immediate!}' following the definite and exact point 
 of fusion. 
 
 For these various reasons, the use of the *'low" fusing, or so-called 
 "enamel bodies," or those which contain a large enough proportion of 
 "flux" to reduce their fusing point below that of pure gold, and to de- 
 crease the stability of form and color, which are imparted largely by the 
 three basal ingredients, cannot be considered at the present time, as be- 
 ing conservatively reliable for this special class of work. 
 
 Furthermore, a series of comparative tests for crushing and tensile 
 strength of most of the various "bodies"" now ])rej)ared. as conducted by 
 Dr. J. E. Nyman, seems to prove conclusively that the most useful and 
 reliable compounds for this class of work are to be found among those 
 which fuse between 2,100° and 2,500° Fahrenheit, with the pyrometer 
 gauged bv the fusing- point of pure gold, as being 2.016°. 
 
 The following table gives the approximate fus- 
 
 Tll$in0 Points. ing points of most of the various bodies now in com- 
 mon use, as well as of the different makes of teeth, 
 as compiled by Mr. J. F. Hamm.ond, and Dr. \\'. A. Capon, in the Ham- 
 mond Electric Furnace : 
 
 "Body." Current. 
 
 Jenkins"s 110 volts. 
 
 Ash's Low Fusing no 
 
 Ash's High Fusing no " 
 
 Moffitt's Porcelain 120 
 
 Brewster's Enamel no 
 
 Consolidated's High Fusing, no 
 
 Whiteley's Porcelain no 
 
 Brewster's Found Body. ... no 
 
 Close's Found Body no 
 
 "White's Porcelain no 
 
 Parker's Body 120 " 
 
 Ash and Sons' Tooth Body, no 
 
 Sibley's Tooth Body no " 
 
 Dental Protective's Tooth 
 
 Body no " 
 
 Justi's Tooth Body no volts. 
 
 S. S. White's Tooth Body, no " 
 Johnson and Lund's Tooth 
 
 Body 120 " 
 
 Luken's' Tooth Body 120 " 
 
 Century Tooth Body 120 " 
 
 •Consolidated Mfg. Co.'s Tooth 
 
 Body 120 " 
 
 Rheostat. 
 
 T 
 
 ime. 
 
 Tern. Fahr. 
 
 I St step. 
 
 2 1 
 
 inin. 
 
 1,544 
 
 1st " 
 
 2 
 
 
 1,544 
 
 4th " 
 
 2 
 
 
 1,904 
 
 2d " 
 
 2 
 
 
 2,047 
 
 4th " 
 
 2 
 
 (( 
 
 2,084 
 
 5th " 
 
 2 
 
 
 2,192 
 
 5th " 
 
 2 
 
 
 2,210 
 
 5th " 
 
 2 
 
 
 2,300 
 
 5th " 
 
 2 
 
 
 2,300 
 
 5th " 
 
 2 
 
 (1 
 
 2,300 
 
 5th " 
 
 2 
 
 a 
 
 2,586 
 
 4th " 
 
 2 
 
 a 
 
 2,264 
 
 4th " 
 
 2 
 
 11 
 
 2,408 
 
 5th " 
 
 2 
 
 '•- 
 
 2,440 
 
 5th step. 
 
 2 
 
 mm. 
 
 2,440 
 
 6th " 
 
 2 
 
 (( 
 
 2,516 
 
 5th " 
 
 2 
 
 " 
 
 2,586 
 
 5th " 
 
 2 
 
 u 
 
 2,606 
 
 5th " 
 
 2 
 
 a 
 
 2,624 
 
 5th 
 
 2,624 
 
-2^2 
 
 **6um enamel" *'Boaie$/' 
 
 The compounds designated as "gum enamel" bodies contain a larger 
 proportion of "flux" than basal bodies, and consequently fuse at a lower 
 degree of heat, and possess less strength. Hence, when their use is in- 
 dicated for the purpose of producing an artificial restoration of the gum 
 color, the major portion of the contour of the piece should be made of 
 the basal "body," and the "gum enamel" subsequently applied where 
 necessary, and only for the purpose of imparting the gum color. 
 
 Previous to the application of the "gum enamel," the basal "body" 
 to be covered by it should be fused until it presents a fairly smooth- and 
 well-vitrified surface. This is necessary, because it is not to be re-fused, 
 and the maximum degree of strength will not obtain until its particles 
 are well coalesced, and all shrinkage has taken place, and if this is ac- 
 complished at the time of the fusion of the "gum enamel," the color of 
 the latter will likely be burned out or dissipated, owing to its greater 
 fusibility, and its surface will present innumerable fractures, as a result 
 of the further shrinkage of the base. 
 
 A new form of "gum enamel" has been introduced by Mr. Robert 
 Brewster, of Chicago. This consists of a finely pulverized "body," which 
 is mixed to the desired consistency with oil, and then painted upon the 
 surface and fused, in the manner previously indicated, in connection with 
 the use of "oil colors." 
 
 It would seem that this should prove to be the ideal method, because 
 the same effect, and greater variations in shading, may be obtained, with- 
 out diminishing the strength or increasing the weight or bulk of the 
 finished piece. 
 
 Hcquirements for Crown and BriddeworR. 
 
 A class of "body" possessing qualities adaptable to the maximum re- 
 quirements for crown and bridgework will thus doubtless belong to the 
 high fusing variety, and should be prepared in one grade; of a sufficient 
 variety of colors, and pulverized only to a degree of fineness which will 
 admit of being nicely carved. This latter feature is essential, because 
 the shrinkage is increased and the fusing point decreased in any given 
 compound in proportion to the degree of fineness in which it is prepared. 
 
 Those which are to be especially recommended are Brewster's 
 ''Crown and Bridge;" "S. S. White's;" the Consolidated Dental Mfg. 
 Co.'s and Whiteley's products, all of which are supplied in neat and 
 compact form, in a good variety of colors, quite adequate to the require- 
 ments for this work. While good results may also be obtained from the 
 use of Brewster's "Inlay Bodies," which consist of tzvo grades — "foun- 
 
253 
 
 elation" and "enamel" — the best possible results arc doubtless facilitated 
 and afforded by the employment of ojie grade of material throughout the 
 construction of the piece, and no difficulty will be encountered in obtain- 
 ing the deisred enamel surface in any of these compounds, if they are 
 fused to the proper degree of vitrification, without the use of any of the 
 lower fusing, or so-called "enamel bodies" in conjunction therewith. 
 
 manipulation of ''Body/' 
 
 That portion of the procedure which involves the manipulation of 
 the "body" requires the most consummate judgment and skill, and, while 
 it is largely true that the strength of the finished piece is much dependent 
 upon the metal constriiction which forms the foundation for the porce- 
 lain, the degree of possible strength may be still further increased by skil- 
 ful manipulation of the latter, or, as the converse is equally true, it may 
 be diminished accordingly. 
 
 When the crown has been taken from the 
 PreiHiration Of €rown. investment, after soldering, it should first be thor- 
 oughly cleaned in 50 per cent sulphuric acid, in or- 
 der to insure the removal of all remaining traces of borax or investment 
 material which may cling to it, and which would be apt to interfere with 
 the subsequent fusion of the porcelain ; and the presence of borax is par- 
 ticularly objectionable, because it acts as a "flux." 
 
 The surplus ends of the dowel and pins should be ground down 
 smooth, and so that they offer no obstruction to the contour, and afiford 
 no weakening of the porcelain, by extending or projecting into it, thus 
 dividing it through the center, and all sharp angles should be nicely 
 rounded. 
 
 These requirements are imperative, as the "body" should occupy all 
 of the space possible. It will not fuse down close nor become attached to 
 unclean or irregular surfaces, and in fusing will usually either draw away 
 from, or fracture over, sharp angles as a result of the shrinkage. 
 
 When these precautions have been observed, the crown should be 
 again treated to the acid ba:th, and then washed freely with clean water ; 
 if a carborundnui stone has been used, care should be exercised to 
 remove all particles which may cling to, or remain upon, the metal, or 
 facing, as the presence of such particles will invariably cause a discolo- 
 ration of the porcelain. 
 
 A close observation of these prerequisites, combined with scrupulous 
 care and extreme cleanliness throughout the subsequent procedure, will 
 materially increase the chances of securing successful results. 
 
 These results will also be greatly facilitated by confining the work 
 
254 
 
 to a place especially prepared for such purposes, or to a portion of the 
 work-bench which has been previously cleaned and arranged ; all of 
 the necessary instruments and appurtenances to be used should likewise 
 be kept perfectly clean. 
 
 When a suitable place to work is thus prepared, 
 SekCtiOlt 9t £olor. and the crown is ready for the application of the 
 "body," its dowel should be grasped firmly between 
 the jaws of a slide pin-vise, which will hold it securely during the build- 
 ing and carving (Fig. 197), and the proper color of "body" then selected. 
 
 This should approach the shade of the facing when one is used, or 
 else of the color desired, as closely as possible, and may be accomplished 
 with the use of the shade-guide, which accompanies the various makes 
 of porcelain. 
 
 If the exact color cannot be matched, and some variation becomes 
 necessary, a shade slightly darker than the facing should be selected, 
 owing to the tendency to bleach somewhat in fusing. In this connection, 
 it must be remembered that the true color of the porcelain compound will 
 be obtained only when it is fused to the exact point of complete vitrifica- 
 
 FicjJ97. 
 
 tion, and that it will become lighter in shade as it is carried beyond, or 
 above, this point. 
 
 An adequate quantity of the "body," which cor- 
 mixing "Body." responds in color to that selected on the shade-guide, 
 should now be placed upon a clean porcelain or glass 
 mixing slab, distilled ivatcr added, and then mixed thoroughly with a 
 suitable spatula, until it assumes the consistency of thick cream. The 
 water may be added in the most convenient and expeditious manner, by 
 means of the "dropper," or "pipette bottle," such as is contained in many 
 outfits for this work and which also serve to keep it pure and clean for 
 subsequent use. 
 
 Sufficient water to insure the desired consistency and thorough mix- 
 ing are quite essential, and any surplus of "body" is not wasted, be- 
 cause it may be replaced in its proper receptacle and used at an- 
 other time. 
 
 Alcohol is sometimes recommended and used because of expediting 
 the evaporation of the moisture from the compound, and thus facilitating 
 
255 
 
 the carving of the mass, but this feature, because of usually being too 
 rapid, is more often an objection than an advantage. 
 
 The addition of a small proportion of gum tragacanth to the water is 
 also recommended as furnishing a means of adding to the cohesion of the 
 mass after the evaporation of the moisture, and thus facilitating the carv- 
 ing and contouring, but its presence is objectionable, because it seemingly 
 acts as a "flux" in the fusion of the porcelain, and is unnecessary, because 
 the manufacturers usually incorporate a small proportion of starch in the 
 compound for this special purpose. 
 
 The use of pure clean water is preferable. It should be distilled, 
 however, because the presence of lime or organic matter may have an in- 
 jurious effect upon the fusion of the porcelain. 
 
 Jlpplyind ana Buiiaind. 
 
 In the manipulation of these compounds, it must be remembered that 
 their tendency to shrink in fusing plays quite an important part, and gov- 
 erns the method of procedure to a large extent. 
 
 In the use of one grade of body, haviiig the 
 "One erade" same fusing point, throughout the construction of 
 Of "Bofly." the piece, the desired shape and contour for the fin- 
 
 ished crown should obtain for the first, or primary 
 
 "bake," and yet it is seldom possible and never expedient to complete it 
 in one "hake," because of the shrinkage. 
 
 This latter feature necessitates tzvo, and sometimes even more, 
 "bakes," though the procedure is somewhat facilitated by forming the de- 
 sired contour, even to the requirements of occlusion for the primary 
 "bake," and the second or iinal application of "body" should then be made 
 for the express purpose of restoring that portion of the original form 
 which has been somewhat changed by the shrinkage incident to the pri- 
 mary fusion or "bake." 
 
 With the crown grasped firmly in the pin-vise (Fig. 197). and the 
 body mixed to the proper consistency, a small quantity should be picked 
 up with the point of a suitable instrument and first forced into the joint 
 between cap and facing. 
 
 This may be facilitated by gently tapping the handle of the pin-vise, 
 or by drawing a coarsely serrated instrument across it, and the procedure 
 should be continued until the "body" is thoroughly packed into the space. 
 
2s6 
 
 A suitable instrument, designed by the author, for universal use in 
 this work, and combining a spatula for mixing, a serrated shank for 
 packing, and a pointed blade for carving, is illustrated in Fig. 198. 
 
 This feature of packing is imperative throughout the entire building 
 up of the crown, as a means of insuring a high degree of integrity in the 
 mass when fused, and of overcoming the tendency toward porosity in 
 fusing, by insuring a close and coynpact coalescence of the particles. 
 
 As the building- up progresses and each additional application of 
 body is thus carried to place, and the contour formed, the procedure may 
 be facilitated by absorbing the excess moisture, as it is brought to the 
 surface, with a clean piece of linen or cotton cloth, or blotting or bibulous 
 paper, until the approximate outline for the finished crown, zvith a slight 
 surplus, obtains. 
 
 The latter part of the procedure may be accomplished with greater 
 ease and facility by mixing the body to a thicker consistency after the 
 joints and all small interstices are well filled. 
 
 When the required form has been obtained, the remaining moisture 
 may be then more quickly evaporated by passing the crozvn over a ftarn^ 
 until the mass is sufficiently dry to admit of being nicely carved. 
 
 The "body" should always remain moist enough, however, to be 
 carved and trimmed without flaking or crumbling, and in the event of 
 its becoming too dry to admit of this, it may be again slightly moistened 
 by touching it with a wet brush. 
 
 In building up bicuspids and molars, after first filling the joint, a 
 narrow strip of blotting paper may be conformed to the outline of 
 the lingual portion of the band, and when held in place will serve as a 
 matrix to hold the body in shape which thus facilitates the procedure. 
 
 Variations of shade may be quite easily obtained 
 Uariations In Shading, by selecting the appropriate colors of body and mix- 
 ing them separately. The color indicated for the 
 base of the crown should then be applied, and built up to the desired 
 point, when the other may be added without allowing the first to become 
 completely dry. 
 
 Their use in this manner afifords opportunity for blending them in 
 fusing, and very artistic results are possible, particularly in those cases 
 where the base should be yellow, or brown, and the incisal or occlusal 
 end blue, or gray, in any of their variations. 
 
 The use of the oil colors previously mentioned 
 U$( Of on Colors, may also be productive of most excellent and ar- 
 tistic results. They should be thoroughly mixed to 
 a thin consistency, with the accompanying oil, applied with a small 
 brush, and separately fused. 
 
257 
 
 Where it is desirable to produce a change in the color of the facing, 
 these colors should be applied at the desired point on the lingual surface, 
 and then fused, after which the "Ijody" may be applied, as required, and 
 the underlying color will show through the more or less transparent 
 facing. 
 
 An appreciable change in the color of the porcelain forming the body 
 of the crown may also be produced by applying and fusing these colors 
 to the surface after the primary bake, when the final contouring may be 
 ■made, the transparency of which, after fusion, will indicate the presence 
 •of the underlying color. 
 
 In simulating the characteristics of remaining natural teeth, grooves, 
 J>its and sulci may be colored or tinted as desired. As these colors fuse 
 lower than the "body," however, this work can be done to the best ad- 
 vantage after the croii'ii has been otherzvise completed ; and when they 
 are used for such purposes on the labial or buccal surfaces of the facings, 
 the desired inequalities should first be ground with a small carborundum 
 stone in the engine, and this outline then properly colored or tinted, and 
 the crown again fused until the colors become vitreous. 
 
 If not too dry, the procedure incident to con- 
 ContOUring touring and carving the "body" is quite simple, but 
 
 and Carving. the artistic results will depend much upon personal 
 
 equation and knowledge of the forms of teeth. 
 
 This may be easily acquired by a close study of natural teeth, and 
 a good plaster model of a full typical arch will assist by serving as a guide 
 in the execution of this work. 
 
 As has been previously stated, anatomically correct outlines are not 
 •essentially necessary, and artistic results may be obtained bv simplv so 
 typifying the cusps as to distinguish between the right and the left, the 
 upper and the lower teeth. 
 
 The requirements of occlusion with the opposing, and contact with 
 the adjacent, teeth may be observed by trying the crown upon the model 
 during the process of carving, and in order to prevent flaking the body 
 ■or changing its given form, it may be carefully and slightly moistened 
 w^ith a wet brush previous to such trials. 
 
 For this reason, it is always necessary to have a good model to 
 vi^hich the crown may be easily adjusted to position, as has been pre- 
 ^^iously recommended. 
 
 In contouring and trimming the porcelain, it must not overlap the 
 band, upon any surface, nor at any point, excepting along the labial or 
 buccal surface, tvhere the facing mechanically retains it, for without 
 such means of retention it will invariably fracture or break away, leaving 
 a rough, sharp, or irregular joint with the cap; and previous to placing 
 
258 • 
 
 the crown in the furnace all particles of body which remain deposited 
 upon, or overlapping, the surface of the facing, or which may have found 
 lodgment on the inside of the cap, or on the under surface of the base, 
 should be carefully removed with a clean, dry brush to prevent it from 
 becoming attached in fusing. 
 
 The brushes used in this work should be of a good quality, such as 
 are employed in water color painting, and the three useful sizes and 
 shapes are illustrated in Fig. 199. The largest size should always be 
 kept dry and used only for smoothing up the work, while the medium 
 
 FicfJQO 
 
 Fiq.200. 
 
 size should be employed for the purpose of moistening the "body," when 
 necessary, and the smaller one only for painting, or deepening the finer 
 lines in carving. 
 
 A very convenient form of simple carving instrument, designed by 
 Mr. Robert Brewster, is illustrated in Fig. 200. 
 
 In trimming the body, the allowance of a slight surplus is demanded 
 by the shrinkage, but the exact extent may only be ascertained with ac- 
 curacy by a familiarity with the compound used, as all vary considerably 
 in such properties. 
 
259 
 
 The crown, when the body has been trimmed, and carved, and when 
 ready for the primary "bake," is illustrated in Fig. 201 A. 
 
 When this desired form, and blending of color. 
 
 Primary "Bake." have been obtained, the crown should be placed in 
 
 the furnace and "baked" until the body becomes 
 
 slightly vitrified, and the particles well coalesced, Imt its surface should 
 
 not be highly glazed at this time. 
 
 This degree of fusion, or vitrification, is preferable to the so-called 
 biscuit bake, commonly advocated, because of the desirability of securing 
 a maximum degree of shrinkage in the primary fusion, but the surface 
 should not be allowed to become smooth and vitreous at this time, be- 
 cause the second application of the body will not adhere so well to it. 
 Fig. 201 B illustrates the appearance of the crown after the "primary 
 bake," and indicates the degree of shrinkage and consequent change of 
 form wliich takes place. 
 
 Fiq.201. 
 
 For the final "bake," the crown should be again 
 Tinal "Bake." adjusted in the pin-vise and the "body" thoroughly 
 mixed, to a thin consistency, and first zvorked' zuell 
 doimi into every crevice and Ussure caused by the shrinkage, and then ap- 
 plied over the surface until the desired contour has been obtained, when it 
 should be fused to the required degree of vitrification for the finished 
 work, which is illustrated in Fig. 201 C. 
 
 If the crown comes out of the furnace after this "bake" presenting 
 an irregular or broken surface of porcelain, such places should be filled 
 with "body," and again fused, though if the proper precautions are ob- 
 served, this will seldom be necessary. 
 
 When two grades of "body" which fuse at dif- 
 "Tounflatlon" and ferent temperatures, such as the so-called "founda- 
 "CliailiCl" Bodies, tion" and "enamel bodies," are used, the requirements 
 are somewhat different from those indicated for one- 
 grade of body, because, if the desired contour of the crown is obtained 
 in the primary formation and fusion, it will be difficult to manipulate the 
 "enamel" body for the final bake, as it will necessarily need to be applied 
 so thinly over the surface of the "foundation" body as to preclude any 
 
26o 
 
 carving, and increase the tendency to flake off, or become detached in 
 places, before fusing. 
 
 Hence, where it is desirable to use two grades, the higher fusing, or 
 "foundation," body should be applied first, only in quantity sufficient to 
 indicate the desired form, as illustrated in Fig. 202 A. 
 
 This should be fused and the lower fusing, or "enamel," body then 
 applied, trimmed and carved as desired (Fig. 202 B), and then fused. 
 
 Ficj.202. 
 
 The increased quantity of the latter body and its greater shrinkage 
 demands an allowance of more surplus than would be necessary if the 
 same higher fusing body were used throughout. 
 
 Prccduficns Incident to fusing. 
 
 No portion of this work is of more importance than the "baking" 
 or fusing of the body, because the strength of the porcelain, and its true 
 color, no matter to which class it belongs, are entirely dependent upon its 
 being properly fused. 
 
 Fi(j.203. 
 
 When the crown is ready for the furnace, it 
 
 Supporting Crown must be adjusted to a suitable form, which will 
 
 inTurnacc. accommodate the dowel, support the base of the 
 
 croivn by allowing it to rest firmly and evenly, and 
 
 which will sustain it in a perpendicular position while in the furnace. 
 
 Whilst platinum trays were first used, and are even now occasionally 
 recommended, for this purpose, their employment is objectionable be- 
 cause crowns not infrequently become attached to them in fusing, and 
 
26 1 
 
 in the subsequent detachment the porcelain may 1)e checked, or the shape 
 of the band altered. 
 
 This attachment may be due to the re-fusion and flowing" of a surplus 
 of the pure gold, when such is used in soldering, or to an excess, or the 
 over-fusing, of the porcelain, but whatever the cause, may be precluded 
 by the use of supports made of fire-clay or chalk, of suitable form. 
 
 The proper adjustment of a crown with and without a band, to the 
 style of support indicated for each, is illustrated in Fig. 203. 
 
 Such supports may be made by moulding a good grade of fire-clay 
 to the desired shape, and "baking" it ; or may be procured in various 
 designs to meet the equally varying requirements of practically inde- 
 structible material from many of the manufacturers of furnaces and 
 "bodies." 
 
 Useful designs for this purpose are supplied by Dr. R. C. Brophv, 
 of Chicago (Fig. 204), or may be made by trimming down a piece of 
 ordinary blackboard chalk to meet the requirements of the case. 
 
 The latter is composed of compounds of magnesium and calcium, 
 which are practically infusible, and being very inexpensive, it is quite 
 useful. Such supports will serve the purpose nicely for individual fus- 
 ings and may even be used two or three times before the form is lost. 
 
 In placing the crown in the furnace, it should 
 
 Placing Crown be observed that the dowel does not extend entirely 
 
 in furnace. through the perforation for its accommodation in the 
 
 support, so as to bring its end in contact with the 
 
 floor of the muffle ; and that the facing does not touch the dome or sides 
 
 of the latter, as such contact in either instance will invariably result in a 
 
 fracture of the facing, due to too rapid heating, or uneven expansion. 
 
 The crown should be held in a perpendicular position, if possible, 
 in order to prevent any change of form which might be induced 
 by the influence of gravity, when the mass is in the fused state; and the 
 body should always present toward the opening or door of the muffle, so 
 that it may be closely watched while fusing. This latter feature is of 
 
262 
 
 special importance, because if the body is not visible to the eye, portions 
 of it may flake off unnoticed during the heating of the case, and neces- 
 sitate a subsequent bake, to avoid which it should always be heated care- 
 fully and watched closely during the fusing. 
 
 As a matter of expediency, the heating of the 
 1)Catin9 Turnace. furnace should begin immediately preceding, or dur- 
 ing, the building up of the crown, so that the muffle 
 will be thoroughly, but not excessively, heated when the crown is ready 
 for the baking. 
 
 When these precautions have been observed, the support carrying 
 the crown should be placed near the opening of the heated muffle and 
 allowed to remain for a few moments, in order to become thoroughly 
 dry before it is placed inside of the furnace. This will preclude blistering 
 the surface of the "body," or the displacement, or flaking, of particles 
 from the crown, as a result of the expansion of the remaining moisture, 
 which would be induced by too rapid heating. 
 
 In placing the crown in the furnace, it should be carried to a posi- 
 tion as nearly in the center of the muffle as possible, or to that point where 
 there are the greatest number of heat units. For the reason that this heat 
 area varies to a considerable extent, it is seldom advisable in the smaller 
 crown furnaces, with the opening in one end only, to fuse more than one 
 or two crowns at a time, and if each is to be baked uniformly, they must 
 be placed crosszvise in the muffle, in order to get such a result, as the 
 temperature decreases toward the door or opening. 
 
 Tuslitg. 
 
 In the fusing of porcelain "bodies" the physical process involved 
 constitutes- changing the powdered granular mass into a vitreous sub- 
 stance, which is then more or less homogeneous in proportion to the 
 thorough admixture of the "flux," or the degree of complete coalescence 
 of all of the particles. 
 
 Hence the proper fusing of these compounds is largely a matter of 
 experience. In the lower fusing "bodies" the proper and desired degree 
 of vitrification may be easily and definitely ascertained by observing this 
 physical change as it is produced by the application of heat. This is also 
 true of the higher fusing bodies, but the greater degree of heat required, 
 and the consequent incandescence within the furnace makes it more diffi- 
 cult. The eye may be trained to a degree of familiarity with the physical 
 changes, however, which will enable the experienced operator to more 
 or less easily distinguish the disappearance of the rough or granular sur- 
 face, and the appearance of the smooth, glassy or vitreous surface even 
 in the, at first, somewhat trying glare of the incandescent heat, v/ithout 
 
263 
 
 greatly endangering- or impairing the sight, because it is not necessary 
 to bring the eyes close enour^h to the furnace to be seriously affected by 
 the heat. 
 
 Smoked or colored glasses may be found useful in this connection, 
 and during the fusing of the "body" the furnace may be occasionally 
 opened for this purpose without danger of fracturing the facing, be- 
 cause the volume of heat is too great to admit of the ingress of cold air. 
 
 \\niile everyone desiring to do this class of work in the most accurate 
 and successful manner should cultivate this degree of familiarity with the 
 characteristic appearance of the "body" in the various stages of vitrifica- 
 tion, it can only be acquired through experience. When the crown is 
 properly placed in the furnace the heat should Ije gradually increased 
 imtil a bright red color is produced. This may be done bv degrees with- 
 out observing the crown itself, but from this point on the latter should be 
 watched closely so as to observe when the rough and granular surface 
 becomes smooth and vitreous, which to the experienced eye is indicated 
 by the degree of incandescence, and as soon as a glassy appearance has 
 spread over the entire surface of the porcelain the heat should be imme- 
 diately turned off. 
 
 Many tests for determining the exact heat re- 
 te$t$. quired to properly fuse the various "bodies" have 
 
 been suggested. Alloys of platinum and gold pre- 
 pared in various proportions with a view to having the test metal melt at 
 the same point as the porcelain would greatly facilitate the fusing, but as 
 this requires a special alloy for each kind of "body," and as these are not 
 on sale ready prepared at the present time, it involves considerable experi- 
 mentation to apply this method. 
 
 Pure gold may be used with some degree of 
 Pure Gold. facility, and its use is recommended as a guide to 
 
 the beginner and an aid even to the experienced. A 
 pellet of foil, or a globule previously flattened on the anvil for each fus- 
 ing may be placed alongside of the crown in the furnace. When this 
 fuses, which may be noted by its assu-iing globular form, the beginning 
 of vitrification of nearly all of the higher fusing bodies will be indicated. 
 
 From the moment of the fusion of the gold to the required or de- 
 sired point of vitrification of the porcelain, time is the only reliable test 
 other than the eye, and as this varies with each furnace and class of bodv, 
 it must be previously more or less definitely ascertained by experimen- 
 tation. 
 
 The separate fusing of several cubes of the "body" used will enable 
 one to ascertain the exact time after the fusion of the pure gold with 
 approximate exactness. \\'hen the desired ooint of fusion has been 
 
264 
 
 reached the heat should be immediately shut off, and the crown allowed 
 to cool slowly until a low temperature obtains, when it may be removed 
 from the furnace. Whilst immediate removal as soon as the heat is 
 turned off, and then placing the crown in a cooling muffle, or in some con- 
 venient receptacle where the air will be excluded until it is cold, is some- 
 times recommended, and is permissible in emergencies, the furnace itself 
 affords the best "cooling muffle," and the slow and gradual cooling of 
 the piece seems to ^'temper' or anneal the body,^ and thus render it less 
 brittle. 
 
 Porosity of the body after fusing is one of the 
 Pcro<ity. chief causes of failure in this work. When this oc- 
 
 curs it may invariably be attributed to one of three 
 causes,- — the use of a surplus of pure gold in soldering; imperfectly 
 "packing" the body in building up the crown, or overfusing it in the 
 furnace. 
 
 FI<].205. 
 
 An excess of pure gold which occupies space and which space sub- 
 sequently becomes a vacuum when the gold is fused in the furnace and 
 absorbed by the platinum, can be avoided by using a minimum quantity 
 of, and properly fusing the gold during the process of soldering. 
 
 There is no excuse for imperfect "packing" if the precautions indi- 
 cated are observed ; and "overfusing," which will be denoted by the be- 
 ginning of a change of form, will not occur if the case is watched closely 
 while in the furnace, or the time test is accurate. This is extremely 
 essential to the success of the finished work, because overfusing burns 
 out, or dissipates, the color, and destroys the integrity of the material, no 
 matter to which class it belongs. 
 
 When the final baking has been completed the exposed lingual sur— 
 
265 
 
 face and entire edge of the i)latinum band should Ije smoothed with sand- 
 paper and polished with cuttle-fish disks, and the crown then tried to 
 place and mounted. 
 
 Turnaces. 
 
 Several varieties of furnaces arc now made for porcelain work in 
 which three sources of heat production are successfully employed, — elec- 
 tricity, gasoline and gas. 
 
 The electric furnaces, or "ovens," in which the 
 
 Electric Turnaccs. heat is obtained by the passing of the current 
 
 through a close coiling of small platinum wire 
 
 slightly imbedded in fire-clay without contact, or wound around the (jut- 
 
 Fici.206. 
 
 side of a thin muffle, possess the advantages of purity, range and control 
 of heat, and of cleanliness and the absence of noise or odor. 
 
 Owing to the absolute purity of the heat thus obtained any possible 
 danger of discoloring the porcelain from "gassing," is eliminated; and 
 for all of the combined reasons mentioned the use of the electric furnace 
 is recommended wherever it is possible to secure suitable commercial 
 current, such as is supplied for incandescent purposes. 
 
 Of the several makes of these furnaces especially constructed for 
 small work, such as single crowns and small bridges, those designed by 
 
266 
 
 Mr. J. F. Hammond, of New York, and Dr. L. E. Custer, of Dayton, 
 Ohio, are to be especially recommended as being neat, compact and serv- 
 iceable, as are also the "Hewett'" and "Pelton" designs. 
 
 These furnaces include a rheostat in serial connection with the muffle 
 or "oven" and forming the base of the furnace, and they work equally 
 well on either the direct or alternating currents of the same voltage. 
 
 While the two former furnaces are made in three sizes, the Hammond 
 No. 2, Fig. 205, and the Custer No. 5, Fig. 206, will be found to be the 
 most convenient size for this special work, though there is no objection to 
 using the larger sizes which are designed for continuous gum work when 
 several crowns at one time, or large bridges, are to be "baked." 
 
 As the larger sizes require more time in fusing, it is more expedient 
 to use the smaller ones for crown work. The opening in the latter, 
 however, is in one end, hence the heat is greatest as the back wall of the 
 muffle is approached. For this reason, if more than one piece is "baked" 
 at the same time, they must be placed crosswise and not lengthzvise with 
 the muffle, in order that the porcelain may be uniformly fused. 
 
 F/Q.P07. 
 
 When the piece is adjusted in the heated furnace it should be 
 allowed to remain for a few moments, and the lever controlling the 
 rheostat then gradually and consecutively pushed from button to button, 
 with an interval of from one to two minutes between each. When the 
 last or highest step required is reached, the case should be closely watched 
 until the body is properly fused, or timed from the fusing of the pure 
 gold, when the lever should be immediately reversed, and the piece 
 allowed to cool more or less slowly before removing. 
 
 Convenient pliers of special design, suitable for inserting or remov- 
 ing the support containing the piece, are illustrated in Fig. 207, but, 
 while these are also very useful for solder work in general, because of 
 their length, a special pair, kept perfectly clean, should be used for this 
 work. In using pliers in the furnace, however, when the current is turned 
 on care must be exercised to avoid bringing them in contact with the 
 wires, and thus possibly fusing the latter or "burning out" the furnace 
 by short-circuiting. ^ •- 
 
26/ 
 
 Ficj,20Q. 
 
 Ficj. 209. 
 
268 
 
 Where it is not possible to secure commercial 
 6il$0UMC TUI'nact$. electric current, and for reasons of possible emer- 
 gency and economy, the gasoline and gas furnaces, 
 as now made, will serve the purpose nicely, and when properly used, will 
 furnish adequate heat. 
 
 While it is true that such facilities do not afford the same degree 
 of absolute purity of heat, there is but little danger of "gassing" or dis- 
 coloring the porcelain, in their use, if the continuity of the muffle is per- 
 fect. 
 
 The gasoline furnace is preferable to gas because the heat produc- 
 tion is aided by means of a pneumatic pump and the one manufactured 
 by Dr. R. C. Brophy, of Chicago, Fig. 208, especially designed for crown 
 
 5-^.210. 
 
 and bridgework, is adequate to the requirements in every respect. This 
 furnace is made in two styles, one with a very thin fire-clay muffle, and 
 the other with a nickel muffle, both of which are quite serviceable, with 
 the preference perhaps slightly in favor of the former. 
 
 The Turner gasoline furnace, Fig. 209, manufactured by the Turner 
 Brass Works, of Chicago, is similar in design (except that the nickel 
 muffle is exclusively used), and is perhaps equally as effective. 
 
 In the use of these furnaces they should be started and well heated 
 before the work is placed in the muffle, and the piece should first be 
 thoroughly dried and heated at the opening before being carried into the 
 inside. 
 
 As the muffle opens from one end the same precautions indicated 
 in connection with rimilarlv constructed electric furnaces should be ob- 
 
269 
 
 served, and when the work is finally adjusted to place, the opening should 
 be closed as a means of confining the heat to the inside and preserving 
 its purity. 
 
 The fusing of the porcelain may be known either by watching with 
 the eye, or by gold and time test, as previously described, in which the 
 "plug" closing the opening of the muffle may be frequently removed for 
 the purpose of observation, and the same requirements incident to turn- 
 ing off the heat, and allowing the work to cool slowly should also be 
 observed. 
 
 If the required heat is to be obtained with facility, the supply of air 
 must not be allowed to become diminished, hence the pump must be used 
 with sufficient frequency to maintain high pressure. 
 
 It is also necessary to watch the condition of the muffle in order that 
 it may be replaced when the continuity becomes destroyed by disintegra- 
 tion, by which means the possibility of "gassing" the work will be largely 
 overcome ; and, the greater facility with which this may be done, to- 
 gether with the inclosed shelf at the opening of the muffle, for heating 
 the work, and the larger size of the latter, constitute the main advan- 
 tages of the first-mentioned furnace. 
 
 The gas furnace designed by Dr. R. C. Brophy, 
 6a$ Turnacw. Fig. 210, may also be successfully used. As a sup- 
 
 ply of air sufficient to afford complete combustion 
 with illuminating gas is needed, however, the employment of compressed 
 air, or the use of the "bellows" becomes necessary, and in the absence 
 of the former, the effort required is of course much greater than that in 
 the use of gasoline. Where compressed air is available, this furnace is 
 to be especially recommended. 
 
 The more or less objectionable odor which emanates from the use of 
 gasoline, however, is overcome, but the noise produced by the combus- 
 tion in each is one of the most unfavorable features in connection with 
 the use of either of these furnaces. 
 
insertion of 6oia fillings in Jlrtificial tcciD. 
 
 CHAPTER XIV. 
 
 Indications. Methods: Foil Gold, "Roman" Gold, In Combination with Backing; 
 
 Procedure. 
 
 The insertion of gold fillings in porcelain facings employed in the 
 construction of crowns and bridges is very often indicated as a means of 
 simulating the remaining natural teeth, and thus observing, and complying 
 with, the requirements of harmony, and with a view to and for the purpose 
 of obtaining increased esthetic and artistic results, as has been previously 
 mentioned. 
 
 In the construction of individual crowns for 
 Tndications. an}- of the anterior teeth, if the remaining adjacent 
 
 natural teeth are more or less freely filled with gold, 
 the crown should almost invariably carry one, and sometimes two, small 
 approximal fillings ; and in bridgework involving the upper anterior teeth, 
 where the lower anterior teeth are likewise filled, the insertion of one or 
 two small fillings in appropriate locations will often aid materially in 
 detracting from the artificial, and adding to the natural, appearance of 
 the work. 
 
 Such filling's should never be inserted, however, with a view of making 
 the work conspicuous, nor for the exclusive purpose of additional remu- 
 neration, and should be no larger than necessary to effect the harmony 
 and legitimate deception which may be thus indicated by the adjacent 
 natural teeth. 
 
 The methods employed in accomplishing this 
 methods. work consist in preparing a retentive cavity and filling 
 
 it with foil gold ; in the use of liquid or "Roman" 
 gold, which is painted over the desired area, and then -fired in the furnace, 
 in a manner similar to that employed in china decorating; and the con- 
 struction of the filling as a part of the backing. 
 
271 
 
 In the employment of this method, which is per- 
 
 Toil Gold. haps the most generally used, and which affords the 
 
 most permanent, expeditious and artistic results, a 
 
 cavity, in the appropriate location and of the desired form, should he first 
 
 outlined in the facing with a small fine carborundum-stone. (Fig. 211a.) 
 
 This outline facilitates the cutting or drilling of a cavity of the neces- 
 sary retentive form and affords a definite marginal edgt for the subsequent 
 adaptation and finishing of the gold. 
 
 When so formed, adequate retention may then be secured by driUing 
 a simple countersunk cavity of sufificient proportions in the center of the 
 outlined area (Fig. 211b), or by cutting retentive grooves (Fig. 211c). 
 
 For the former purpose, which is more generally applicable to small 
 cavities, an inexpensive diamond drill, to be used in the engine, is made 
 by the S. S. White Dental Manufacturing Com])any (Fig. 212a). while 
 the retaining grooves, which are best adapted to larger cavities, may be 
 easily cut with a sm.all copper disk coated with diamond dust, which is 
 also prepared for this and similar purposes (Fig. 212b), or with the 
 
 "cavity cutting"' outfit manufactured by the same company, and which 
 consists of a set of engine instruments of oval form, and graded sizes, 
 and a cutting material composed of carborundum dust and glycerol. 
 
 While this latter method accomplishes the \vork nicely, it is scarcely 
 so expeditious as the two former procedures, in the use of which the 
 rapidity of their cutting properties is facilitated, and the danger of 
 fracturing the facing is entirely eliminated, by the free, use of oil or 
 glycerine as a lubricant. This saves the instrument, and prevents the 
 creation of heat otherwise induced bv friction, which might cause fracture. 
 
 When the proper retention has beer secured, the cavity should be 
 thorough!}' cleaned with soap and water and dried with alcohol and hot 
 air, and then filled with small pellets of gold in the ordinary manner, and 
 finished as usual (Fig. 21 id). 
 
 While it is usnall}- aflvrsable to defer the insertion of such fillings 
 until after the campletron of the work, in order that any subsequent 
 .scratching or defacing of the surface may be prevented, it may frequently 
 
272 
 
 become necessary, or seem desirable, to insert them before the construc- 
 tion of the work, or the assemblage of the parts. 
 
 This may be essential in bridgework constructed with gold to admit 
 of placing the cavity in the desired location upon the. approximal surface, 
 and when here or otherwise indicated the procedure may be greatly facili- 
 tated by imbedding the facing in a base of modelling compound or sealing 
 wax, as a means of holding.it securely '(Fig. 213). 
 
 In porcelain work, however, the procedure must necessarily be 
 deferred until the piece has been finished, in order to preclude fusing the 
 gold, and the same is likewise advisable in single crowns, for the reason 
 mentioned, and in any event the preparation of cavity and insertion of 
 filling should be don« at the same time. 
 
 O 
 
 a 
 
 Fi<j. 213. 
 
 Z/'^. 212. 
 
 In the use of the so-called "Roman" gold, which 
 Roman Gold. is prepared for similar decorative purposes, and quite 
 
 applicable to this, the cavity area should be first out- 
 lined, as indicated in Fig. 211a, and the gold then mixed into a paste 
 of proper consistency and painted thickly over the surface, being careful 
 to observe that it closely follows and evenly approximates the cavity 
 margins. 
 
 The facing should now be placed near a flame, or close to the previ- 
 ously heated furnace, and allowed to remain until the gold has become 
 thoroughly dry, when it should be placed in the furnace and "fired" until 
 the gold fuses, which may be readily observed by its vitreous appearance. 
 After allowing to cool more or less slowly, the filling may be easily 
 finished and polished with burnishers, or Unc cuttle-fish disks, and the 
 bufif wheel. 
 
273 
 
 In gold work such fillings should be made before the final attachment 
 ■of the facing to the metal parts, with solder, while in porcelain work the 
 lower heat required to fuse the gold demands that they be made after the 
 •completion of the piece. 
 
 While this method affords artistic results, the objections to it lie in 
 the fact that such fillings are likely to be less permanent, because of a 
 tendency to flake and chip. 
 
 A method involving a less simple detail, and 
 Tn Combination requiring more time, perhaps, but productive of very 
 
 Witb Bacliing. artistic results, is applicable to gold work, and con- 
 
 sists of making the filling in combination with and 
 :as a part of the backing. 
 
 Its employment is indicated more especially, however, in simulating 
 .approximal fillings involving the incisal angle, which is sometimes desir- 
 able, and which would be more or less difficult by the other methods, 
 
 Ticcause of. the limited opportunity aft'orded by the ordinary facing for 
 .-securing adequate anchorage for such fillings. 
 
 When such a filling is indicated, or where it 
 
 Procedure. may be desirable to employ this method, the facing 
 
 should be first ground to the proper and required 
 
 -adaptation, and then prepared for the reception of the backing, in the 
 
 nisual manner. 
 
 That portion of the porcelain which involves the location and area 
 •of the desired cavity formation and gold restoration should then be ground 
 away on a slight bevel tozuard the lingual side, tmtil a perfectly smooth 
 rmarginal outline has been secured (Fig. 214a). 
 
 A backing of about 34 gauge pure gold should now be adapted to 
 the facing, and burnished up well against the cavity margin, allowing a 
 surplus of about 1/32 of an inch to project beyond the latter, and upon 
 the incisal end (Fig. 214b). When this has been accomplished, a piece 
 of 22 karat gold plate, 29 or 30 gauge, should be adapted to this, extend- 
 ing from the pins to the incisal end, and projecting out to the original 
 
outline of that portion of the facing which has been destroyed (Fig. 
 214c). 
 
 This forms a matrix, indicating the desired formation of the iiUing, 
 and the two backings should now be removed and united with solder in 
 the manner previously described in connection with "re-enforced backings.'^ 
 Their detachment from the facing without danger of changing the shape 
 of the thinner one is made possible and facilitated by the slight lingual 
 bevel given to the cavity wall in its preparation. 
 
 When their union has been eiTected, the matrix formed by the two 
 backings should be filled with 22 or 20 karat solder until the desired 
 contour obtains (Fig. 2i4d). 
 
 This should then be adjusted to the facing, securely attached by 
 bending the pins, and finished with files, stones and disks until the adapta- 
 tion of the backing and the contour of the filling are as desired (Fig. 
 2i4e). when the piece may l^e completed and finished in the usual manner. 
 
 In securing the desired contour of the filling with solder, a high 
 karat must, of course, be used, because of the susceptibility to discolora- 
 tion, and clean flux must be applied to avoid a pitted surface. 
 
 In flowing the solder, it is also well to observe the precaution of 
 fitting a piece of gold or platinum wire or plate into the matrix before the 
 procedure, as this insures a preservation of the adaptation of the pure 
 gold to the cavity margin, which otherwise might be somewhat changed 
 bv shrinkage, if solder alone be used. 
 
finishing, PolisDind and mounting. 
 
 CHAPTER XV. 
 
 Finishing. Polishing: Facilitating Procedure. Precautions. Gold Plating. Cyan- 
 ide Solutions, Prepared Solutions. Mounting: Preliminary Adjustment; 
 Temporary Mounting; Permanent Mounting; Use of Cement; Procedure; 
 Dowel Crowns, Shell or Telescop- Crowns, Insuring Accuracy of .Adapta- 
 tion to Root, Two or iMorc Crowns, Therapeutics. Use of Gutta Perclia ; 
 Advantages, Disadvantages, Procedure; Dowel Crowns, Shell or Telescope 
 Crowns, Final Mounting. Combining Cement and Gutta Percha ; Procedure. 
 Variations of Procedure; Use of Chloropercha ; Use of Shellac and Sandarac; 
 Rubber Tissue. Final Precautions. Removing Crowns Mounted with Gutta 
 Percha. 
 
 The finishing-, poHshing- and mounting of crowns, while ahnost 
 equally as important as any other special portions of the work, are, never- 
 theless, quite often neglected or done in a more or less perfunctory man- 
 ner, because of not being fully appreciated. 
 
 This should not be so in any single instance, for the reason that 
 proper finishing and polishing adds materially, not only to the artistic 
 appearance, but also, and particularly where gold is used, to the increased 
 hygienic condition presented in the finished piece; and successful mount- 
 ing has much to do with the degree of comfort and permanency of the 
 operation. 
 
 Tinishiitd. 
 
 When the case has been removed from the investment, it should 
 first be treated to the acid bath for a sufficient length of time to insure the 
 thorough removal of all products of oxidation, and of all particles of 
 investment material and "fiux." After this has been effectually accom- 
 plished, the acid should be thoroughly removed by washing freely with 
 clean water, and the case then finished in accordance with the require- 
 ments, and with the maximum of artistic possibilities to which gold and 
 platinum are so highly susceptible, as is evidenced in the jeweler's art, 
 and in jeweler's products. 
 
 The primary efforts in finishing should consist in obtaining the re- 
 quired contour; the desired obliteration of all joints, and evenness and 
 
2/6 
 
 smoothness of the surfaces ; and should inckide removing, or diminish- 
 ing any undesirable or unnecessary display of metal upon any surface. 
 Owing to the small size of the piece, this may usually be best accom- 
 plished with small carborundum stones, of coarse and medium grit, used 
 in the engine. These should be followed with emery or sandpaper disks 
 of medium grit^ and subsequently with very fine, or cuttlefish, disks, 
 until every scratch is removed, and the surfaces are perfectly smooth. 
 
 A more finished and artistic appearance may be given to the lingual 
 surfaces of anterior crowns with gold backings by making an effort to 
 reproduce the natural shape and form of this surface in the gold (Fig. 
 
 FA 
 
 ^•215, 
 
 F/cj. 216. 
 
 215), which may be easily and quickly done with a knife-edge carbo- 
 rundum stone, and plug-finishing burs. 
 
 Polisbiiid. 
 
 This should then be followed by highly polishing the metal with felt 
 and brush wheels on the lathe. The primary polishing should be ob- 
 tained with a thin-edge felt wheel (Fig. 216) and moistened pumice stone 
 of medium grit; and the wheel should be previously soaked. in water, so 
 that it will absorb and carry the pumice stone with it during the proce- 
 dure. 
 
 When the desired smoothness of surface has been thus obtained, the 
 final polishing should be given first with a stiff brush-wheel (Fig. 217a), 
 used with the pumice stone, and then with moistened whiting, or pre- 
 cipitated French chalk; and this should, be followed with a soft brush- 
 
277 
 
 nq.2/7. 
 
2/8 
 
 wheel (Fig. 217b) and whiting^ and finally with a cotton "buff" wheel 
 (Fig. 217c) until a highly polished and mirror-like surface presents. 
 
 Such a finish requires but little effort and but a few moments' time 
 and is always indicated because of the more artistic appearance of the 
 work, and of its being thus rendered more hygienic. The more highly 
 the surfaces of metal are polished, the less susceptible are they to dis- 
 coloration, and the more permanent and self-cleansing is the finish, be- 
 cause less opportunity is thus afforded for the subsequent attachment of 
 accumulations in the mouth. 
 
 Jewelers' rouge and various other polishing compounds are often 
 advocated and are employed with the "buff" wheel for the final polishing, 
 but nothing seems to produce better results than whiting, if properly 
 
 Fi'cj. 218. 
 
 used, as indicated ; and the reddish color imparted by rouge to the metal, 
 together with the discoloration of the fingers incident to its use, are more 
 or less objectionable. 
 
 As single crowns, and particularly those of the 
 Tacilitatins Procedure, "shell or telescope" variety, are somewhat difficult to 
 handle while polishing, various styles of "crown- 
 holders" have been devised for facilitating this part of the work. 
 
 The most ingenious and perhaps universally useful of these instru- 
 ments is the one known as Fahey's Ideal Crown Holder, manufactured 
 by the Dental Specialties Company, of Chicago (Fig. 218). This is adapt- 
 able to almost any size of crown, because of one blade being removable ; 
 
279 
 
 and, the spring being adjustable, it holds the crown securely with little or 
 no danger of distorting its shape. 
 
 A similar device which is also useful for this purpose is known as 
 the "Burgess" crown holders, and is shown in hig. 2iy. 
 
 The filling of the crown with compounds of sealing wax, and then 
 inserting a piece of wood into it while it is hot, is sometimes recom- 
 mended, but is objectionable because of the difficulty of removing the 
 compound after the polishing is completed ; and the fitting of the end of 
 a piece of wood of suitable length to the interior of the crown is likewise 
 a poor method, because of the possible distortion of the shape of the band 
 in so doing. 
 
 While dowel crowns are not quite so difficult to handle in the polish- 
 ing, the use of one of the pin vises previously recommended may some- 
 times be found convenient. 
 
 Although it is scarcely possible to give too high 
 
 Precautions. a polish to the exposed surfaces of metal which are 
 
 to be permanently fixed in the mouth, it is, however, 
 quite possible, and indeed sometimes quite easy, to polish through the 
 thinner portions of a crown in the use of disks and felt wheels ; hence, 
 in polishing, extreme care should be exercised to prevent such a mishap, 
 as well as to preclude any unnecessary thinning of such parts. 
 
 6oia Platittd. 
 
 An increased artistic effect, and a more permanent finish, may be 
 obtained by subjecting the piece to the electroplating process, after it has 
 been highly polished. This imparts a uniform rich yellow color to all 
 metal surfaces and affords a surface of pure gold which is more or less 
 permanent, and which is not so easily attacked and discolored by the 
 chemical action of the secretions. 
 
 Solutions for this purpose may be made by dis- 
 gyatUdC Solution. solving fifteen grains of the chloride of gold in a 
 porcelain or glass vessel containing about four 
 ounces of distilled water, and then adding to this a like quantity of water 
 into which about thirty or forty grains of pulverized potassium cyanide 
 has also been previously dissolved in a similar vessel. This is known as 
 the "cyanide solution," the approximate formula for which, as generally 
 employed, is as follows : 
 
 Chloride of gold gr. xv. 
 
 Cyanide of potassium gr. xxx. to xl. 
 Distilled water oz. viii. 
 
 A small ordinary "primary" or "dry cell" battery may be used, and 
 the work to be plated should be attached to the negative pole and then 
 
28o 
 
 suspended in the solution, with a piece of thin pure gold plate likewise- 
 suspended from the positive pole, avoiding contact between the two. 
 
 If the piece is zvell finished and highly polished, and then washed 
 with bicarbonate of sodium to remove all traces of organic matter, and' 
 then fastened to the pole by so coiling the wire as to have a well-distrib- 
 uted contact over the surface of the metal to be plated, a few minutes' 
 immersion in the solution will afford the desired result, after which it. 
 should be again highly polished with the "hiiff" wheel. 
 
 Solutions which may be used without a battery 
 Prepared Solutions, are prepared for this purpose, and while they seenr 
 to afford good results, the deposit of gold is prob- 
 ably not so heavy, and hence not so permanent, and the solution can only 
 be used until it becomes inactive. 
 
 In their use a sufficient quanity of the solution should be placed ixt 
 a porcelain or glass vessel and heated until ■ivarin, and the work then at- 
 tached to a strip of pure zinc and immersed therein. 
 
 Moderate heat and slight agitation will effect the desired result in a 
 few moments, and the permanency and effectiveness of the solution may 
 be increased by suspending a small piece of pure gold plate on another 
 zinc strip hooked over the edge of the vessel so that the gold is immersed. 
 
 mountifld 
 
 No portion of the entire procedure incident to the construction and 
 application of the work is of more importance than the detail involved 
 in its secure and permanent attachment to the root. 
 
 In order that such a fixation may be secured with reasonable facility, 
 the medium used must possess sufficient plasticity to admit of the proper 
 and accurate adjustment of the crown, and to completely fill the interven- 
 ing space between it and the root, and must then afford a substantial and 
 more or less insoluble and impervious union between the two. 
 
 Previous to any effort toward permanent 
 
 mnminary mounting, the crown should ahvays be adjusted to- 
 
 >iaiu$Tment. . . , / . . . , 
 
 position on the root, as a means of ascertaimng with 
 
 absolute certainty that it meets with all the requirements of fit, occlu- 
 .sion, etc., as well as to admit of making any changes in its form or shape 
 which may be necessary, and of subsequently repolishing, which cart 
 never be done so well after permanent fixation is secured. 
 
 The adjustment may be greatly facilitated in so far as discomfiture 
 to the patient is concerned by slightly moistening the interior of the band 
 with 95 per cent carbolic acid, or by carefully bathing the gum surround- 
 ing the root with a two or a four per cent solution of cocaine just pre- 
 vious to inserting the crown. 
 
28 I 
 
 The former procedure is jxrhaps the more simple, equally effective 
 and less dangerous one. and usually affords sufficient anesthesia of the 
 parts to admit of the subsequent permanent mounting without any ap- 
 precialjle discomtiture ; and any possible injury to the tissues from the 
 escharotic effect may be overcome by bathing them with alcohol as soon as 
 the crown is forced to place. 
 
 The driving of the crown to position is never warrantable or neces- 
 sary if the adaptation is anywhere near correct; anterior crowns can 
 usually be forced to place with the fingers, and a firm closure of the jaw 
 will aid in adjusting those on the posterior teeth. In the event of the 
 absence of occluding teeth, a small flat piece of wood may be used to 
 advantage here, as indicated in the fitting of bands. 
 
 When it has been observed that the adaptation is correct, the crown 
 should be then removed and mounted, as the patient should never be dis- 
 missed, no matter hotv firm it may remain in place at first, without the 
 presence of some medium of attachment which may preclude its becom- 
 ing loosened, and any possible distortion of the fit or shape which might 
 result therefrom in wearing, not overlooking the danger of swallowing it. 
 
 Ccmporarv mounting. 
 
 In the event of permanent mounting being contraindicated for a 
 time, the crown may be temporarily mounted in a manner which will ad- 
 mit of its being worn without danger of becoming loosened or distorted in 
 shape, and of its being removed with facility whenever necessary. 
 
 When such a procedure may for any reason be indicated, temporary 
 stopping will serve as a sufficiently substantial medium to afford attach- 
 ment from sitting to sitting, or for a few days' duration, but it does not 
 possess sufficient integrity to be reliable for any great length of time. 
 
 In its use, the root should be dried with alcohol and hot air, and a 
 sufficient quantity thoroughly heated and placed inside of the band, and 
 the crown then quickly forced to place, after which it may be chilled with 
 a spray of cold water directed upon the crown, and the surplus then 
 trimmed away. 
 
 Crowns so mounted may be easily removed with a pointed instru- 
 ment, hooked over the edge of the band, as heat higher than the temper- 
 ature of the body is scarcely ever necessary to destroy or reduce the ad- 
 hesive property of this material, which accounts for its not being reliable 
 for more permanent usage. 
 
 Permanent mountind. 
 
 The requirements of a permanent mounting are best obtained at the 
 present time in the use of the oxyphosphate of zinc cements and gutta 
 
282 
 
 percha. Amalgam was formerly used to some extent but has been prac- 
 tically abandoned in view of the greater facility with which either of these 
 may be successfully employed, and the absence of adhesive properties. 
 
 Use of Cement 
 
 Cement is perhaps the more generally employed because of the facility 
 with which it may be manipulated, combined with its adhesive properties 
 and inherent strength when moisture is excluded. 
 
 Fi<j.220, 
 
 The disadvantages incident to its use are the temporary irritation to 
 the tissues in mounting ; the possible m*ore or less permanent irritation 
 which may be induced by hidden particles accidentally left in contact 
 with the gum after motinting; its susceptibility to dissolution when ex- 
 posed to the action of the secretions ; its possible shrinkage in crystallizing, 
 and the extreme difficulty with which a crown may be removed, and par- 
 ticularly a dowel crown, when occasion demands. 
 
283 
 
 When it has been ascertained that the adapta- 
 Proccdurc. tion is correct, and when the crown is ready to be 
 
 permanentl}' mounted, its inner surface should l)e 
 cleansed with alcohol, and thorouj^hly dried with hot air. 
 
 The root should now be rendered aseptic by a careful bathing with 
 carbolic acid, or by the use of pyrozone or hydrogen peroxide, or any 
 good antiseptic, and then thoroughly dried with pledgets of cotton. 
 
 Thorough drying is absolutely essential and may be facilitated by 
 precluding contact of the lips, cheeks, or tongue, with cotton rolls or pads, 
 and then using alcohol or chloroform evaporated with compressed air, or 
 warm air from the chip blower. The non-absorbent cotton rolls prepared 
 
 /^y. ee/. 
 
 in various sizes and lengths by Johnson and Johnson are very convenient 
 for such purposes. The use of these in the anterior part of the mouth 
 is illustrated in Fig. 220, and if the root is in the posterior part of the 
 mouth, a "mouth prop" adjusted in the opposite side to hold the mouth 
 open will often be found very useful, and the cotton rolls may be efifec- 
 tively retained with a clamp adjusted to an adjacent tooth. Fig. 221. 
 
 A good reliable medium setting cement should now be mixed to a 
 •creamy consistency, which should, and can best, be done by an assistant, 
 when possible, in order that the operator may confine himself to observing 
 that the root does not become moistened. 
 
284 
 
 If the crown possesses a dowel, the canal, or 
 Dowel Crowns.. canals, should first be thoroughly filled with the 
 cement. This may be accomplished by using a root 
 canal plugger and a pumping action, until the cement has been carried to 
 the extreme ends. A cement syringe for this purpose has been devised 
 by Dr. H. L. Cruttenden, but its use usually involves more time than is 
 necessary or warrantable for such a simple procedure. 
 
 When the canal has been thus well filled, the dowel and interior of 
 the cap should be coated or covered with a layer of cement, which, if 
 done by the assistant during the filling of the canal, will greatly expedite 
 the operation, and the crown should then be quickly and firmly pressed 
 to its proper position on the root. 
 
 After becoming assured of its having assumed the proper relation, 
 the patient may be requested to close the mouth until the cement has at 
 least partially crystallized, the length of time required for which will be 
 indicated by the surplus remaining upon the mixing slab. It is desir- 
 able that the first stages of the setting of the cement should be obtained 
 under pressure. Therefore the operator should press firmly upon the 
 crown with the finger or a piece of soft wood for at least five minutes. 
 
 The crystallization may be hastened somewhat by directing warm 
 air from the chip blower upon the crown, and when sufficiently hard, all 
 surplus should be carefully removed with pledgets of cotton, and a sharp- 
 pointed explorer passed carefully around the band beneath the gum. 
 
 A ligature drawn through the interproximal space may further in- 
 sure the removal of any remaining surplus at these points, which precau- 
 tions are always advisable, because of the extreme irritation to the gum 
 which is produced by such hidden particles after their complete crystalli- 
 zation. 
 
 Coating the outside of the band along the cervix with vaseline or oil 
 just previous to mounting is recommended as a means of facilitating the 
 removal of the excess by preventing its adhering to the edge or surface of 
 the crown. 
 
 In mounting the "shell or telescope" crown, the 
 "Shell or same detail is indicated, but as a larger quantity of 
 
 telescope" Crowns, cement must be placed in the crown, care should be 
 exercised to have it cover all surfaces, and be devoid 
 of air spaces, in order to insure the complete filling of the entire interven- 
 ing space between it and the root. The proper quantity is governed, of 
 course, by the length of the root which projects or extends into the crown. 
 
 As soon as the crown is forced to place, the mouth should be imme- 
 diately closed and the occlusion observed, and when this is as it should 
 be, which will be indicated by the normal contact of the adjacent oppos- 
 
^85 
 
 ing natural teeth, a roll of cotton should be placed between the crown 
 and the opposing teeth, and a steady and firm pressure of the jaw in 
 normal occlusion maintained until the cement has crystallized, in order to 
 prevent any possible displacement. 
 
 The same precautions incident to the removal of all excess cement 
 should then be observed with equal rare, and before dismissing the patient 
 it should be carefully and finally noted that the crown does not occlude 
 too hard, as subsequent discomfiture will invariably result if this con- 
 dition exists. 
 
 If any doubt exists as to the accuracy of the re- 
 Tnturing JlCCUracv of lation of the cervical edge of the crown to the per- 
 Jldaptati^n to Root, iphery of the root, some means of insuring a close 
 joint between them should be observed. 
 This may often be aided materially by slightly reducing the circum- 
 ference of the edge of the band with curved or small, pointed pliers, just 
 
 previous to the final mounting, as it may have become somewhat en- 
 larged, by stretching, in the fitting and preliminary trials. 
 
 The use of a smooth foot plugger adjusted to the automatic mallet 
 may also be found useful, and particularly along the buccal edge, after 
 the crown has been mounted ; and the approximal edges may be brought 
 into closer contact by inserting a small amalgam burnisher into the inter- 
 proximal spaces, and exerting some little effort in this direction. Either 
 a suitable burnisher, such as is illustrated in Fig. 222, or the foot-plugger^ 
 may often be employed to good advantage upon the lingual surface, but 
 in the use of either, some little care should be observed to avoid produc- 
 ing sharp angles at the corners, and yet to secure a close adaptation and 
 particularly at the bifurcation of the roots. 
 
 In extreme cases of ill adaptation or of exceedingly constricted 
 necks, a good result may often be obtained by encircling the crown with 
 a piece of German silver, or copper wire, from 24 to 26 gauge, passed 
 through the interproximal spaces, and the ends then twisted from the 
 
286 
 
 buccal side (Fig. 223), until the loop breaks. This affords a uniform 
 compression of the edge of the band by condensing the molecules, but 
 in effecting it, it should be observed that the wire does not slip beneath 
 the edge of the band, which tendency may be overcome by slightly flatten- 
 ing that portior which rests against the lingual surface of the crown, or 
 which forms the center of the loop. While ordinary silver suture wire, 
 or .that made from other alloys or metals may be used, those recommended 
 give the best results because of their tensile strength. 
 
 Wherever possible, all of these procedures should be observed, or 
 executed, after the crown has been properly mounted, and a firm closure 
 of the jaw should be maintained, in order to prevent lifting it from its 
 
 f/^.223. 
 
 proper relation. The cement should first be allowed to become partially 
 crystallized, also, in order that any slight hemorrhage produced may in- 
 terfere as little as possible with its perfect crystallization. 
 
 An instrument designed for compressing the edge of the band after 
 mounting has been devised by Dr. Rudolph Beck, of Chicago (Fig. 224,), 
 and may sometimes be found more or less useful for this purpose. 
 
 When two or more crowns are to be inserted at 
 
 two or more Crowns, the same sitting, each should be mounted separately, 
 
 as the crystallization of the cement seldom affords 
 
 opportunity for the thorough and accurate mounting of more than one 
 
28; 
 
 with each mixing; and the operator should never he hurried, nor make 
 any effort to expedite matters to too great an extent in this procedure. 
 
 In cases of extreme pain after mounting, which 
 therapeutics. is sometimes induced by the irritating influence of 
 tlie cement upon inflamed or liypersensitive tissues, 
 but which is usually only temporary, relief may be afforded by painting 
 the gums around the neck of the crown with a two or a four per 
 cent solution of cocaine ; or with the tincture of iodine, or the usual rem- 
 edies for counter-irritation. A spray of hot water is also sometimes very 
 effective, and where an astringent may be indicated, in cases of conges- 
 tion, zinc sulphate or a saturated solution of tannic acid in glycerine may 
 be employed. 
 
 Use or Gutta Percba. 
 
 The difficulty encountered in the removal of crowns mounted with 
 cement, and particularly of dowel crowns, has created a demand for some 
 
 medium which would afford a secure and reliable attachment, and which 
 would at the same time admit of subsequent removal in the event of 
 necessity, without requiring the destruction of the crown or of any ap- 
 preciable amount of tooth structure. 
 
 The ordinary red or pink base-plate gutta 
 
 JVdpantases. percha, skilfully manipulated, seems to meet such 
 
 requirements in admitting of easy removal, as well 
 as to possess the additional desirable qualities of offering sufficient in- 
 tegrity in the attachment, and of being insoluble, non-irritating, and more 
 or less impervious. 
 
 Its use also affords a somewhat cushion-like seat for the crown, 
 which is an advantage because of relieving the "deadened blow" in the 
 stress of mastication, and of thus reducing the shock, and diminishing 
 the tendency of porcelain to fracture, as compared with a more non- 
 yielding medium. 
 
The disadvantages incident to the employment 
 
 Disadvantages. of this material lie mainly in the skill and time re- 
 quired to successfully manipulate so refractory or in- 
 tractable a substance ; and yet its integrity as a substantial mounting is due 
 to such properties, and will, of course, increase in proportion thereto, so 
 long as it is capable of being rendered sufficiently plastic to be properly 
 moulded, in the adjustment of the crown. 
 
 While its employment is probably more especially indicated for dowel 
 crowns, this same essential property may here prove a disadvantage, if 
 any great surplus is present, by offering sufficient resistance to expand 
 the band, and thus destroy the accuracy of its adaptation. 
 
 This objection may be overcome, however, by careful manipulation 
 in obtaining the maximum of plasticity, and avoiding the presence of any 
 unnecessary surplus. Successful results will depend upon a willingness 
 to consume time, and to observe the detail with deliberate painstaking 
 care, as well as in the acquirement of the necessary degree of skill; and 
 will increase in proportion thereto. 
 
 In its manipulation, the material should be cut 
 Procedure. into narrow shreds or strips, from one-half to one 
 
 inch in length, and these should then be slowly and 
 carefully heated until plastic. The heating should be done at the chair, 
 and may be best accomplished by placing them on a porcelain-lined 
 electric gold annealer, such as is manufactured by Mr. M. M. 
 Kerr, of Detroit, Mich. ; or upon a mica slab placed over a flame, where 
 they should remain until the mounting is completed. The Custer electric 
 gold annealer has an accompanying porcelain slab which may also be used 
 for this purpose. 
 
 Direct contact with the flame should always be avoided, as this de- 
 stroys the working properties of the material by rendering it harsh and 
 tough. 
 
 While the gutta percha is being thus heated. 
 
 Dowel Crowns. the dowel of the crown should be spurred with a 
 
 sharp knife-blade, and it and the interior of the cap 
 
 then slightly moistened with a solvent of gutta percha, to facilitate a 
 
 secure attachment. Oil of cajeput is probably the best solvent for this 
 
 purpose, though oil of eucalyptol or chloroform may be used. 
 
 When thus prepared, a piece of the gutta percha shotild be picked 
 up with foil carriers, coiled around the dowel from its apex downward. 
 Fig. 225 A, and then packed down closely with tlie fingers. If one piece 
 does not appear to be sufficient for the first trial, another may be added, 
 tmtil what seems to be adequate is obtained, but a surplus should be 
 avoided. 
 
289 
 
 The crown should now be placed upon the heater, and the canal and 
 end of the root then moistened with a spray of water from a syrmge, m 
 order to prevent the gutta percha from adhering, after which the heated 
 crown may be grasped with a napkin and forced to position. If no great 
 surplus has been used, it will go readily to place without driving, when 
 it should be at once removed, and small pieces of the heated material 
 added, where needed; it is then placed again upon the heater, the root 
 moistened, and this procedure continued until the gutta percha is moulded 
 to fill the space between crown and root, when the correct relation exists. 
 
 All surplus should now be trimmed off even with the edge of the 
 band, and the crown then replaced upon the heater. 
 
 In the event of the presence of too much gutta percha to admit of the 
 proper adjustment, the surplus should be trimmed away with a hot m- 
 strument, and the crown reheated and carried to place, until the proper 
 .relation maintains. 
 
 The procedure indicated in the mounting of the 
 
 Shell or "shell or telescope" crown is the same, except that 
 
 telescope Crowns, the gutta percha may be cut into small square pieces, 
 
 of convenient size ; and these should be placed in the 
 
 bottom of the crown and around the joint between cusp and band, until 
 they may be gradually moulded to fill the space. 
 
 Up to this point, the root should be moistened 
 Tfnal mounting. previous to each application or trial of either style 
 of crown, in order that its removal may be made 
 •easy by preventing adhesion. 
 
 When ready for the final mounting, the crown should be again 
 placed upon the heater, and allowed to remain until the root has been 
 rendered aseptic, and then thoroughly dried in the manner indicated in 
 ■connection with cement. It should now be moistened with the oil of 
 cajeput, or with a thin solution of chloropercha, and the crown then 
 picked up with the napkin, and forced to place, where it should be held 
 .firmly for a few moments, until the gutta percha loses its heat, which 
 may be hastened by a spray of cold water. 
 
290 
 
 £otnbinin9 Cement and Qutta PercDa. 
 
 While either cement or gutta percha may be used in mounting shelf 
 or telescope crowns, on the posterior teeth, the advantages of both may 
 be obtained for dowel crowns by combining them. This may be done in 
 such manner as to admit of the subsequent removal of the dowel, in case 
 of accident or necessity without any great difficulty, and to overcome any 
 possible danger of enlarging the narrow band, such as may possibly result 
 from the use of gutta percha alone. 
 
 Whatever advantages cement may possess as a mounting medium, 
 it is seldom the best practice to surround the dozvel exclusively with this 
 material, because of the extreme difficulty of ever removing it from the 
 root. Hence, if one is not sufficiently skilled in the manipulation of gutta. 
 percha alone, some means of facilitating the removal of such crowns,. 
 without injury to the root, is always indicated. 
 
 This may be accomplished by using sufficient. 
 
 Procedure. gutta percha, in the manner described, to surround 
 
 the dowel only (Fig. 225B) and then completing' 
 
 the mounting by filling the cap and coating the walls of the canal with 
 
 cement, thus obtaining, in a measure, the advantages of both, with lb" 
 
 minimum of the objections of each. 
 
 Various combination cements in w4iich gutta percha filings, or gutta 
 percha in solution, is incorporated with the oxy-phosphate of zinc, are 
 advocated, but as their use is at present somewhat experimental they are 
 not recommended. 
 
 Uariations of Proceaure. 
 
 The skill required to successfully manipulate gutta percha has 
 caused the adoption of several variations of procedure, each with a view 
 of accomplishing the desired result with greater facility and expediency. 
 
 A thick solution of gutta percha in chloroform 
 Use ©f 0Woropcrcba, is sometimes employed for the entire mounting of 
 dowel crowns, but is not recommended, because of 
 the shrinkage of such medium, due to the evaporation of the chloroform. 
 This shrinkage will, of course, afford some opportunity for the subsequent 
 loosening of the crown, and thus diminshes the stability and permanency 
 of the attachment. 
 
 It may be used around the dowel and on the inner surface of the cap,, 
 however, in place of the base-plate gutta percha, and when so employed,, 
 the chloroform should first be evaporated by passing over a flame, and- 
 the crown then mounted with cement, as indicated. This prevents the 
 adhesion of the cement to the surfaces of the dowel and cap, which, of; 
 
29.1 
 
 course, facilitates the removal of the crown, but not to the extent afforded 
 by the use of the gutta percha alone, when it entirely fills the canal. 
 
 A heavy coating of very thick shellac or sand- 
 U$C Of Shellac arac varnish over the dowel, and on the inside of the 
 or Sandarac. cap will also prevent the adhesion of the cement to 
 
 the metal, and thus facilitate the removal of the 
 crown, and particularly of the dowel ; and while it is better to use either 
 one of these alcoholic solutions than nothing at all, their similar employ- 
 ment only affords the same advantages and limitations mentioned in con- 
 nection with the use of chloropercha. 
 
 A preparation of rubber in the form of very 
 Rubber tissue. thin tissue, which is quite adhesive, is recommended 
 for similar use by Dr. W. F. Lawrenz, of St. Louis, 
 but at the present stage of its experimental application, it seems to offer 
 no particular advantages over the preceding materials, and is more diffi- 
 cult to manipulate. 
 
 Tina! Precautions. 
 
 When the mounting has been completed with apparent satisfaction, 
 the patient should never be dismissed until it has been carefully ascer- 
 tained that the crown is firm, and that the occlusion and all surrounding 
 conditions are favorable; and a further precaution against any possiblo 
 subsequent displacement, annoyance or discomfiture should be observed 
 by requiring the patient to return in the course of a few days for final 
 inspection. 
 
 Keitio<)ind Crowns mountca witb Gutta Pcrcba. 
 
 The removal of crowns mounted with gutta percha may be 
 easily effected by applying sufficient heat to the exposed portion of 
 the crown to soften the material. This may be done by heating the 
 beaks of a pair of heavy pliers of good size, placing them on the crown, 
 and sustaining the contact until the heat is conveyed throughout its length, 
 which will usually be noted by a response from the patient, when the 
 gutta percha surrounding it will be sufficiently softened to lose some of 
 its adhesive properties, and admit of the ready detachment of the crown 
 with a hooked or pointed instrument. 
 
 In this procedure, care should be exercised to guard the face and 
 lips of the patient, as well as to protect the porcelain, which may be aided 
 by cotton rolls or pads ; and the pliers should be heated in the laboratory, 
 or where the heating may not be observed by the patient, and then car- 
 ried to the chair wrapped in a napkin or towel, with only the beaks ex- 
 
292 
 
 posed, as a matter of convenience to the operator, and of protection and 
 relief from fear to the patient. 
 
 A more convenient method which may sometimes be employed with 
 success has been suggested by Dr. C. B. Rohland. This consists in plac- 
 ing a leather or moose-hide polishing wheel in the engine and revolving 
 it with rapidity against the crown until the friction will thus produce 
 sufficient heat to admit of its removal. 
 
INDEX 
 
 Abrasion, l-.xtensive, liiy. 
 
 Acid Bath, ;.'4. 
 
 Accuracy of iVdaptation Without Band, 203. 
 
 Accurate I'ltting JJowels, '^2'J. 
 
 Adaptation of lacings, I4S. 
 
 Adapting Backing, I'S:',. 
 
 Facing, \S:i. 
 Adhesive Wax, :i\). 
 Adjusting Cusp, 'Jo. 
 Adjustment of Dowel, lyi. 
 Alignment, 14il. 
 Alloying, IJ. 
 Alloys, 10, Hi. 
 
 Uorrance's, ID. 
 
 Tusiblc, :?ll. 
 
 of Gold, 10. 
 Amalgam, Application of, 117. 
 Anatomical Relations, 48. 
 Anterior Crowns, :i;iti, 231. 
 
 Anterior Teeth, Applications to the, 118, 129. 
 jVpplication of Amalgam, 117. 
 
 Davis Crown, 242. 
 
 Detachable and Replaceable Facings, 159. 
 
 F'acings to Bicuspid Crowns, lo2. 
 
 Partial Bands, 155. 
 
 Removable Crowns, 171. 
 
 Riveted Facings, 15(1 
 
 Saddle-]?ack Teeth to Bicuspid and :\[olar 
 Crowns, 130. 
 Application of the [ntradental Band, 173. 
 
 Logan, Crown. 
 
 to Deciduous Teeth, 124. 
 
 Individual Roots, 117. 
 
 Irregularities, 131, 171. 
 
 Separated Molar Roots, 115. 
 
 the Anterior Teeth, 118, 129. 
 Apposition, 27. 
 Approximal Contact, 49. 
 Articulation and Oci;lusion, 49. 
 Articulators, Improved, 187. 
 Artificial Teeth, Insertion of Gold Fillings in, 
 
 269. 
 Ash's Crown Swaging Device, 05. 
 Autogeneous Soldering, 35. 
 
 Backing, 130. 
 
 Adapting, 1 33. 
 
 in Combination V.'ith, 272. 
 
 of j'acing, 149. 
 
 Rei)lacenient of Facing and, 183. 
 
 Soldering, 133. 
 Baird System, 102, 123. 
 Bake, l-'inal, 259. 
 
 Primary, 259. 
 "Balling Up," 27. 
 Band, 130. 
 
 Accuracy of Adaptation Without, 202. 
 
 and Ca]., With, 201. 207. 
 
 and Dowel, With, 227. 
 
 and Dowel Crown, Preparation for, 02,138. 
 
 Band, .application of the Inlradenlal, 173. 
 
 Preserving Continuity of, 127. 
 
 Primary, 105. 
 
 With, lis, 2 43. 
 
 Without, lis, 244. 
 Bands, 7'J, 110, 227. 
 
 ^Application of Partial, 155. 
 
 Partial, 237. 
 Base Metals, 11, 29. 
 Bicuspid Crowns, Application of Facings to, 
 
 132. 
 Bite, 14S. 
 
 and Impressions, 100, 107, 229. 
 
 Occluding, 84. 
 Blanks. 113. 
 
 Forming, 109. 
 Block Teeth, Soldering, 29. 
 Blowpipe, Oxy-IIydrogen. 33. 
 Bodies, J'oundation and Enamel, 259. 
 
 Gum Jinamel, 250. 
 
 High and Low Fusing, 249. 
 Body, Manipulation of, 253. 
 
 ^iixing, 254. 
 
 One Grade of, 255. 
 Borax, 20. 
 Box Method, 104. 
 Brass, 1 9. 
 
 Brewer's Method, 177. 
 Brewster Crown, 213. 
 Bridges, Cantilever, 117. 
 Brown Crown, the, S. 
 Bryant's Method, 164, 181. 
 Biittner Crown, 0. 
 
 Canals, Preparation of, 69. 
 Cantilever IJridges, 117. 
 Cap, Re-enforced, 107, 235. 
 
 Separating Dowel and, 184. 
 
 With Hand and, 201, 207. 
 Caries, Extensive, 46. 
 
 Carved Cusp and Special Die Methods, 88. 
 Carving and Swaging, 122. 
 Casting Flasks, 107. 
 Cements, 262, 289. 
 Cervical Curvature, 140. 
 
 End, 14 9. 
 Chloropercha, 290. 
 Cigrand's Method, 175. 
 Coin Gold. 16. 
 Color, 141. 
 
 and Harmony, 141. 
 
 Oil, 141, 256. 
 
 Selection of, 254. 
 Coloring Matter, 248. 
 Compounding Solders, 10. 
 Composition Characteristics and Manipulation 
 
 of Porcelain Bodies, 247. 
 Consideration of the Metals, 15. 
 Contouring, 82. 
 
 and Carving, 257. 
 
Cooling After Soldering, 34. 
 <Jrown Slitting Forceps, 126. 
 Curvature, cervical, ] 40. 
 Cusp, Adjusting, 93. 
 
 Formation, l-'rocesses for, 87. 
 
 J'ormation Without Models, 95. 
 
 Soldering, 93. 
 
 Solid Cast, 94. 
 Cusps, 116, 168. 
 Cyanide Solution, 279. 
 
 Davis and Logan Crowns, Use of the, 241. 
 
 Davis Crown, A])plication of the, 242. 
 
 Davis Crowns, 166. 
 
 Deciduous Teeth, Application to, 124. 
 
 Development of Crown Work, History and, 1. 
 
 Devitalization, Feasibility of, 54. 
 
 Die and Die-Plate Methods, 97. 
 
 I'late Methods, 97, 122. 
 Die-Plates, 97. 
 Dies, 91, 108, 193. 
 
 Individual, 97. 
 Diminution of Normal Space, 172. 
 Dorrance s Alloy, 19. 
 Dowel, Adjustment of, 191. 
 
 and Plate, 68, 236. 
 
 Crown, Preparation for Band and, 02. 
 
 Crown, the Band and, 188. 
 
 Crown Without Band, Preparation for, 67. 
 
 Crowns, 188, 196, 2S.S, 288. 
 
 Separating Cap and, 184. 
 
 With Band and, 227. 
 Dowels, 49, 124, 137, 140, 1S8, 193, 229. 
 
 Accurate Fitting, 229. 
 
 Inseparable, 67, 199. 
 
 Separable, 68, 199. 
 
 Substituting Separate, 210. 
 
 Use of Two, 167. 
 Drying and Pleating, 41 . 
 Dwight's Facing, 163, 179. 
 
 Enamel Cleavers, Use of, 64. 
 
 Removal of, 64. 
 English Tube Teeth, 3. 
 Esthetic Relations, 50. 
 Ivxcising Bicuspids and Molars, 63. 
 
 Forceps, 184. 
 
 Jncisors and Cuspids, 63. 
 Extension for Support of Facing, 172. 
 Extensive Abrasion, 129. 
 
 Caries, 46. 
 
 Pacing, 130, 168. 230. 
 
 Adapting, 133. 
 
 and Backing, Replacement of, 183. 
 
 ]'>acking of, 149. 
 
 Dwight's, 163. 
 
 Extension for Support of, 172. 
 
 Mason's, 160. 
 
 Roach's. 161. 
 
 Soldering. 134, 231. 
 
 Use of Flat Band, 168. 
 
 Without, 234. 
 Facings, Adaptation of, 148. 
 
 Application of Riveted, 156. 
 
 Application of Detachable and Replaceable, 
 1 59. 
 
 Replacement of, 176. 
 
 Replacing Bicuspid on Molar, 182. 
 l-'easibility of Devitalization, 54. 
 Feldspar, 248. 
 F'ellowship Crown, 2 J 4. 
 Finishing, 94, 115, 151, 155, 274. 
 First Application of Porcelain Crowns, 2. 
 Flame, 30. 
 
 Flasks, Casting, 107. 
 Flux, 25, 248. 
 Fluxed Wax, Parr's, 26. 
 Foil Gold, 270. 
 Forceps, Crown Slitting, 126. 
 
 Excising, 184. 
 Forming Blanks, 109. 
 
 Foster Crown, 4. 
 
 Fractured Roots, Treatment of, 71. 
 Fracturing of Porcelain F^acings, 28. 
 Free Exposure of the Root, 56. 
 Furnace Heating, 262. 
 
 Placing Crown in, 261. 
 
 Supporting Crown in, 260. 
 Furnaces, 265. 
 
 Electric, 265. 
 
 Gas, 269. 
 
 Clasoline, 268. 
 l^isible Alloys, 20. 
 Fusing, 262. 
 I'using Points, 251. 
 
 Precautions Incident to, 260. 
 
 Gates-Bonwill Crown, 5. 
 German Silver, 20. 
 Gold, 15. 
 
 Alloys of, 16. 
 
 and Platinum, 17. 
 
 Coin, 16. 
 
 Fillings in Artificial Teeth, Insertion of, 
 269. 
 
 Foil, 270. 
 
 Plating, 279. 
 
 Platinized, 17. 
 
 Pure, 263. 
 
 Recovering and Refining Waste, 22. 
 
 Refining, 21. 
 
 Roman, 271. 
 
 Soldering, 33. 
 
 Solders, 18. 
 Gravity, 30. 
 Gutta Percha, 287, 289. 291. 
 
 Hard Wax, 39. 
 
 Harmony, 141. 
 
 Heat, Uniform, 27. 
 
 Hist9ry and Development of Crown Work, 1. 
 
 Hollingsworth System, 99, 123. 
 
 and Baird Systems, 123. 
 Plow Crown, 7. 
 Howland-Perry Crown, 5. 
 Hygienic Considerations, 172. 
 Plypertrophy, Treatment of, 55. 
 
 Imiiression, 85, 148. 
 
 and Bite, 106, J 67, 229. 
 
 of Root, 193. 
 Incisal of Occlusal End, 149. 
 In Combination With Backing, 272. 
 Indications and Requirements, 45. 
 
 for Porcelain Jackets, 239. 
 Individual Dies, 97. 
 
 Roots, Application to, 117. 
 Inseparable Dowels, 67, 199. 
 Insertion of Gold Fillings in Artificial Teetli, 
 
 269. 
 Investing, 39, 153, 169. 
 
 and Investment Materials, 36. 
 
 Object of, 36. 
 Investment, 231. 
 
 Preparation of, 41. 
 
 Preparing Case for. 38. 
 
 Requirements of ar., 38. 
 Iridium, 16. 
 Irregularities, Application to, 131, 171. 
 
 Jacket Crowns, 129, 238. 
 
 Kaolin, 24 8. 
 Karat, 15. 
 
 Liquid Soldering Fluid, 26. 
 Logan Crown, 7, 203. 
 
 Application of the, 244. 
 Logan Crowns, Use of the Da\ 
 Dowry System, 101, 123. 
 
 and Millett Systems, 123. 
 
 Mack Crown, 4. 
 Malformation, 47. 
 Malformed Teeth, 129. 
 
 ind, 241. 
 
Alalposiliun, iT, 171. 
 
 Manipulation, 30. 
 
 Mason s I'acing, 100. 
 
 Metals, Alloys and S.-ldcrs, lu. 
 
 Annealing of, 13. 
 
 J5ase, '4\). 
 
 Chemical Action oi, i:i. 
 
 C'liemical and I'hysical I'roiicrucs ut, 1-^. 
 
 Color of, VJ. 
 
 Consideration of the, 15. 
 
 Ductility of, 1~'. 
 
 Fusibility of, 1-'. 
 
 MalleabilUy of, I ;. 
 
 Soldering of, 13. 
 
 Tempering of, 13. 
 
 Tenacity of, 13. 
 
 Welding of, 13. 
 Millett's Systems, IIIO, 1~'3. 
 Mitchel's Method, ITS. 
 Model Making, Accuracy in, 18u. 
 Model, Swaging, 113. 
 Models, 37. 
 
 Preparing, 107. 
 Molar Koots, Application to Separated, 115. 
 JMould, 113. • 
 Mounting, 207^ 274. 
 
 Final, 289. 
 
 Permanent, 281. 
 
 Temporary, 281. 
 
 Ivloble and Base Methods, 11. 
 
 •Object of investing, 3C. 
 Occluding Bite, 84. 
 Occlusal Ends, Incisal of. 149. 
 Occlusion and Articulation, 49. 
 Oxy-Hydrogen Blowpipe, 33. 
 
 Paralleling, Converging or Diverging Teeth, GU. 
 
 Parr's Fluxed Wax, 20. 
 
 Partial Bands, 237. 
 
 Perforated Roots, Treatment of, 70. 
 
 Peripheral Trimming, (>5. 
 
 Physiological Considerations, 54. 
 
 Relations, 48. 
 Plate and Dowel, (iS, 236. 
 Platinized Gold, IT. 
 Platinum, 15. 
 Solder, 17. 
 Soldering, 33. 
 Use of, 153. 
 Polishing, 275, 276. 
 Porcelain Bodies, Composition, Characteristics 
 
 and Manipvilation of, 247. 
 Porcelain Crowns, 221. 
 
 Facings, Fracturing of, 28. 
 Jackets, Indications for, 239. 
 "the Shell or Telescope Crown in Combin- 
 ation With, 128. 
 Work, 213. 
 Porosity, 264. 
 
 Preparation for Band and Dowel Crown, 62. 
 for Dowel Crown Without Band, 67. 
 for Shell or Telescope Crown, 57. 
 for Shell or Telescope Crown with I'orce- 
 
 lain Facing, 62. 
 of Canals, 69. 
 of Investment, 41. 
 of Roots, 62. 
 Prepared Sokitions, 280. 
 Preiiaring Case for Investment, 38. 
 
 Models, 107. 
 Preserving Continuity of Band, 127. 
 Primary Band, 1 05. 
 Primitive Application of Crowns, 2. 
 Processes for Cusp l''ormation, 87. 
 Protection of Unsupported Walls, OS. 
 Pure flold Soldering, 33. 
 
 Ready-Made r'Arms, 125, 
 
 Recovering and Refining Waste Gold, 22. 
 
 Rc--cnforccd Caii, 107, 235. 
 
 Kelining Gold, 21. 
 
 Relations, Esthetic, 50. 
 
 Removaoie Crowns, Application to, 171. 
 
 Removal of Enamel, 01. 
 
 Removing and Repairing, 120, 175. 
 
 Removing Crowns Mourned with Gutla 1 ercha. 
 
 291. 
 Removing Wax, 40. 
 Reijairing, 12T, 170, 201,J.15. 
 
 and Kemoving, 120, IT^i. 
 Replacement of 1-acing and Packing, 183. 
 
 of hacings, 170. 
 Replacing Bicuspids o'l Molar l-acing=, 1S2. 
 Requirements ot an Investment, 38. 
 Riclimond Crown, 0. 
 Riveting, 158. 
 Roach's Facing, 101. 
 Roman Gold, .. I'l. 
 Root, Impression of, 193. 
 Preparation, 190, 227. 
 Roots, Preparation of, 52. 
 Rubber Tissue, 290. 
 Saddle-Back Teeth to Bicuspid and Molar 
 
 Crowns, Application of, 130. 
 Sand Bath, 24. 
 Sandarac, 29<». 
 Scott's Method, 114. 
 Seamless Method, m:;. 
 SejjaraOle Dowels, 08, lO'.i. 
 Separating Cap and Dowel, 184. 
 Separation of Teeth, 173. 
 Shading, X'ariations in, 250. 
 Shell or Telescope Crown, 4, T4, 284, 289. 
 
 in Combination with Porcelain, 128. 
 Shellac, 29<i. 
 Shrinkage, 28, 250. 
 Silica, -.^48. 
 Silver Solder, 20. 
 Soft Solder, 21. 
 Soldering, 35. 
 Solder, Silver, 20. 
 
 Soft, 21. 
 Soldering, 23, SO, 131, 151, 154, 109, 226. 
 ^Vutogeneous, 35. 
 Backing, 133. 
 Block Teeth, 29. 
 Cooling After, 34. 
 Cusp, 93. 
 Facing, 134, 231. 
 Fluid, Li(|uid, 20. 
 Gold, 33. 
 Platinum, 33. 
 Pure Gold, 33. 
 Soft, 35. 
 
 With Investment, 31. 
 Without Investment, 30. 
 Solders, 10, 17. 
 
 Compounding, 19. 
 .Solid Cast Cusps, 94. 
 Strength, 50. 
 Stress, 48. 
 
 Substituting Separate Dowels, 210. 
 Swaging, 92, 110, 113. 
 and Carving, 122. 
 Device, Ash's Crown, 95. 
 Model, 113. 
 Plate. 193. 
 Sweating Process, 34. 
 System, Baird, 102, 123. 
 Hollingsworth, 99, 123. 
 Lowry, 101, 123. 
 Millett's, 100, 123. 
 Telescope Crown, Preparation for Shell or, 57. 
 With Porcelain Facing, Preparation for 
 
 Shell or, 62. 
 or Shell Crown. •(, 74, 284, 289. 
 or Shell Crown, in Combination with Por- 
 celain, 128. 
 Telescoping, 50. 
 Tests, 203. 
 Tem)iorary Crowns, 217. 
 
Therapeutics, 53, 286. 
 
 The Shell or Telescope Crown in Combination 
 
 with Porcelain, 128. 
 To Prevent Unsoldering, 34. 
 Treatment of Fractured Koots, 71. 
 
 of Hypertrophy, 55. 
 
 of Perforated Roots, 70. 
 Trimming, Peripheral, 65. 
 Tube Crowns, 216. 
 
 Method, 166. 
 
 Underwood's Method, 178. 
 Uniform Heat, 27. 
 Unsoldering, to Prevent, 34. 
 Use of Enamel Cleavers, 64. 
 Flat-Back Facing, 168. 
 
 Platinum, 153. 
 
 the Davis and Logan Crowns, 241. 
 
 Two Dowels, 167. 
 
 Vulcanite Teeth, 170. 
 
 Wax, Adhesive, 3'J. 
 
 Hard, 39. 
 
 Removing, 4 0. 
 Webb Crown, 8. 
 Weston Crown, 7. 
 Williams's Method, 174, 
 With Band, 118, 243. 
 
 and Cap, 201, 207. 
 
 and Dowel, 227. 
 Without Band, 118, 244. 
 
 Facing, 231. 
 
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