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 http://www.archive.org/details/practicaltreatis1888evan 
 
A FRACTip/VL TREATISE 
 
 v.; ^ 
 
 ^ Went SU . . :^ 
 New Yorl 
 
 Artificial Crown- and Bridge-Work. 
 
 GEOEGE EYANS. 
 
 \A^ITH 500 ILLUSTRATIONS 
 
 PHILADELPHIA: 
 
 THE S. S. WHITE DENTAL MFG. CO. 
 1888. 
 
"c^ \ 
 
 tc 
 
 V^ 
 
 Copyright, 1888, by George Evans. 
 
 PRESS OF PATTERSON tc WHITE. PMILA. 
 
To the fAemhers 
 
 of the 
 
 First District Dental jSociety of the jState of J^ew Yorl<, 
 
 this bool< is respectfully dedicated 
 
 by 
 
 The /iuTHDR. 
 
PREFACE. 
 
 The aim of tlir aiitlior in jircparin*;' this treatise is to sii[t[)ly 
 an admitted want in dental literature. 
 
 Much that is new in dentisti'v and much more that is, b}' 
 maiiv jiractitioiiers at least, oidy imperl'ectly understood, is 
 invohed in crown- and bridge-work. Properly practiced it 
 approaches a fine art; hut misapprehension of" the princi[»les 
 underlying it, lack of judgment in their application, a)id im- 
 proper practice have conspired to pre\eiit its general acceptation 
 by the })rotession, and it has in conse([uence been oidy partially 
 indorsed or even wholly condemned when a better understan<hng 
 would liave insured its hearty approval. Still, its possibilities 
 are seen to be so great that at ])resent no other branch of 
 dentistry more engages the attention of [mictitioiK'rs, and in no 
 other is a livelier interest or a greater desire foi- real information 
 manifested. 
 
 The subject is liere presented almost wholly from the practical 
 stand-point, in the behef that the utility and esthetic advantages 
 of crown- and bridge-work may l)e thus more rea(hly made 
 apparent to the practical men in dentistry. To this end (lie 
 various methods described are classified in systems, and their 
 treatment is made as concise as their importance will permit. 
 Due credit is given where the methods and (k'scriptions of others 
 are used. 
 
 Acknowledgment is gratefullj^ rendered to Drs. IT. A. Parr, 
 of New York City, E. Parmly Brown, of Flushing, N. Y., and 
 M. II. Fletcher, of Cincinnati, for personal assistance. 
 
 George Evans. 
 
 New York, Aujrust, 1888. 
 
CONTEI^TS. 
 
 PAGK 
 
 Introduction 13 
 
 Artificial Crown- and Bridge-Work 17 
 
 PART I. 
 
 PREPARATORY TREATMENT OP TEETH AND ROOTS FOR CROWN-WORK. 
 
 CHAPTER I. 
 The Pulps of Teeth — Their Preservation or Devitalization 22 
 
 CHAPTER II. 
 Devitalization of the Pulp 25 
 
 CHAPTER III. 
 Pulpless Teeth — Their Treatment and Disinfection 29 
 
 CHAPTER ly. 
 Chronic Alveolar Abscess 33 
 
 CHAPTER V. 
 
 Shaping Teeth and Roots for Crown-Work 37 
 
 PART II. 
 
 ARTIFICIAL CROWN-WORK. 
 the porcelain system. 
 
 CHAPTER I. 
 
 Porcelain Crowns 44 
 
 The Bon will Crown 45 
 
 The How Crowns and Methods 51 
 
 The Gates Crown .58 
 
 The Foster Crown 69 
 
 The Howland Crown 59 
 
 The Logan, Brown, and New Richmond Crowns 60 
 
 Remarks on the Use of Porcelain Crowns 69 
 
 9 
 
10 CONTENTS. 
 
 CHAPTEK ir. 
 
 PAGE 
 
 Porcelain Crowx with Gold Collar Attachment 70 
 
 CHAPTER III. 
 The Weston Crown 73 
 
 CHAPTER IV. 
 Porcelain Crowns with Rubber or Vulcanite Attachment 76 
 
 THE gold system. 
 
 CHAPTER V. 
 Porcelain and Gold Crown without a Collar 77 
 
 CHAPTER VI. 
 Gold Collar Crowns 79 
 
 The Construction and Adaptation of Collars 79 
 
 CHAPTER VII. 
 
 Gold Collar Crowns with Porcelain Fronts 84 
 
 Incisors and Cuspids 84 
 
 Bicuspids and Molars 87 
 
 All-Gold Collar Crowns for Bicuspids and Molars constructed in Sections 89 
 
 CHAPTER VIII. 
 
 The Gold Seamless Cap Crown 99 
 
 Incisors, Cuspids, and Bicuspids 99 
 
 Bicuspids and Molars 101 
 
 CHAPTER IX. 
 Gold Seamless Contour Crowns 105 
 
 CHAPTER X. 
 
 Gold Crowns with Porcelain Fronts for Teeth with Living Pulps 113 
 
 CHAPTER XI. 
 
 Special Forms of Gold Crowns with Porcelain Fronts 117 
 
 The Parr Crown 117 
 
 The Leech Crown 118 
 
 The Low Crown 119 
 
 CHAPTER XII. 
 
 Crowning Fracturbd Teeth and Roots, and Irregular Teeth 121 
 
 Longitudinal Fracture of the Crown and Root 121 
 
 Fracture of the Crown, with Slanting Fracture of the Root..... 122 
 
 Methods of Crowning in Cases of Irregularity 122 
 
CONTENTS. 11 
 
 CHAPTER XIII. 
 
 I'AGK 
 
 Partial Crowns 124 
 
 CHAPTER XIV. 
 
 FlNISHINQ AND PoI.lSIIIVO — PrOCBSS OF CEMENTATION 128 
 
 Finisliing and Polishing Crown-Work 128 
 
 Insertion and Cementation 128 
 
 PAET III. 
 
 BRIDGE-WORK. 
 
 CHAPTER T. 
 Construction of Bkidgk-VVork ],37 
 
 CHAPTER II. 
 
 Spkoial Procks.ses AND APPLIANCES IN Bridge-Work 148 
 
 CHAPTER III. 
 Extension Bridges I.55 
 
 CHAPTER IV. 
 Double Bar- Bridges I59 
 
 CHAPTER V. 
 
 RXTKNSIVK AtI'LTCATIONS OF CPvOWN- AND BRIDGE- WoRK 102 
 
 CHAPTER VI. 
 Repair of Crown- or BraDGE-WoRK 170 
 
 CHAPTER VII. 
 
 Detachable and Rkmovable Bridge-Work 172 
 
 Dr. Winder'.? Sectional Crown Method 172 
 
 Dr. Litch's Method 1 74 
 
 Dr. K. W. Starr's Methods I77 
 
 Dr. C. M. Richmond's Method 182 
 
 Dr. C. S. Waters's Method 182 
 
 Dr. Parr's Meth ods 183 
 
 CHAPTER VIII. 
 Removable Plate Bridges 187 
 
 CHAPTER IX. 
 The Low Bridge 198 
 
 CHAPTER X. 
 Dr. Knapp's Methods 203 
 
12 . - CONTENTS. 
 
 CHAPTER XI. 
 
 PAGE 
 
 Dr. Melotte's Method 208 
 
 CHAPTER XII. 
 Partial Cap and Pin-Bridge Methods 212 
 
 CHAPTER XIII. 
 
 The Mandrel System 221 
 
 Detachable Bridge- Work 233 
 
 CHAPTER XIV. 
 
 Porcelain Bridge-Work 238 
 
 Dr. Brown's Method 238 
 
 PAET IV. 
 
 MATERIALS AND PROCESSES USED IN CROWN- AND BRIDGE-WORK 
 
 CHAPTER I. 
 Plate and Solders 249 
 
 CHAPTER II. 
 Porcelain Teeth 252 
 
 CHAPTER III. 
 Molds and Dies...., 253 
 
 CHAPTER IV. 
 
 SOLDER[NG 255 
 
 CHAPTER V. 
 Instruments and Appliances 257 
 
INTRODUCTIOK 
 
 Of the origin of the art of dentistry no one can speak with cer- 
 tainty, as its early history is shrouded in the mists of anti(^uity; 
 ])ut dental operations are recorded in \ery remote times. 
 
 Kefereuces are made to the art in tlie writings of Hippocrates, 
 in the tit'th century B.C. Martial, the Latin poet, in the first 
 century B.C., says that a Jloiuan dentist " Cascellius is iti the 
 habit of fastening as well as extracting the teeth." To Lelius 
 he says, "You are not ashamed to purchase teeth and hair;" 
 and adds tliat " the toothless mouth of Egle was repaired with 
 hone and ivory; " also, that " Galla, more refined, removed her 
 artificial teeth during the night." 
 
 Horace, in the same century, cites the case of the " sorceresses 
 Canidia and Sagana running through the city and losing the one 
 her false hair, the other her false teeth." 
 
 Galen, the celebrated physician, in the second century a.d., 
 also speaks of the art of dentistry as being then practiced. 
 
 These early operations were limited to the extraction of 
 offending teeth and the replacement of those which had been 
 lost with substitutes which were retained in position by means 
 of narrow bands or ligatures attaching them to the adjoining 
 natural teeth, and without the use of plates. Crude as thev 
 were, they formed the first expression of the art of dentistry, a 
 beneficent art from the beginning, in that it sought to restore 
 pathological or accidental defects. Confined to the simplest 
 operations, it existed for centuries, and then was apparently 
 
 13 
 
14 INTRODUCTION. 
 
 lost during the Dark Ages, to reappear when the more general 
 diffiision of knowledge ushered in the modern era of science 
 and invention. 
 
 After its revival, dentistry, so much of it as was known, was 
 m a measure a secret art, tlie practice of which even within the 
 memory of men now living, and they not the oldest, w^as in- 
 volved in mystery; but recent progress has lifted the veil, and 
 dentistry, in the treatment of the teeth on correct, scientific, 
 rational principles, has developed an art and a science which 
 have given it honorable rank among the professions. In its 
 two-fold evolution it has absorbed from every available source 
 whatever would l^roaden its science or ^terfect its art. It calls 
 to its aid anatomy, }:>hysiology, pathology, chemistr}^, thera- 
 peutics, metallurgy, sculpture, and mechanics, with each of 
 which it stands in closer or more remote relation ; and the 
 practitioners of dentistry who have Ijecome the most eminent 
 and useful have been men of broad attainments and great 
 versatility of talent. 
 
 In the history of all progress,movements apparently of a more 
 or less reactionary^ cliaracter are recorded. In the useful arts 
 especially it is not uncommon to iind a return to forms and 
 methods formerly used l)ut long since discarded and forgotten. 
 So in dentistry we find methods of treatment and modes of 
 j)ractice once in vogue l)ut long fallen into disuse, revived 
 with im})r()vements and modifications that stamp them as practi- 
 cally rediscoveries. 
 
 These movements are not to be regarded as retrogressive, 
 because the modifications which accompany the reintroduction 
 of practical ideas and inventions stamp them as real advances, 
 and indicate clearly that the cycle of knowledge is ever widen- 
 ing with experience. This volume demonstrates how modern 
 dentistry has utilized the principles of some of the simplest 
 original operations, and by " proving all things, holding fast that 
 
INTRODUCTION. 15 
 
 which is good," has attained its present honorable position in 
 both its scientific and artistic departments. 
 
 The history of dentistry of hitter years is, in In'ief, a recital of 
 progress and improvement. Tlie medical profession oflicially 
 recog-nized it as closely allied to medicine l>y inviting its re})- 
 resentatives to take part in the late International Medical Con- 
 gress on the footing of professional equality. 
 
 Such is the position which dentistry has attained. Much of 
 the progress which has made its present elevation possible must 
 be credited to the dental profession of the United States, which 
 has l)een justly termed the cradle of modern dentistry. Here 
 the validity of the idea that scientific knowledge should form 
 the basis of training for practice was first demonstrated l»y the 
 successful establishment of dental schools; here the first journal 
 for the interchange among dentists of thought and experience 
 was founded; here the first association having for its object the 
 uplifting and upholding of dentistry by the niutual helpfulness 
 of its })ractitioners had its origin; here, in a word, dentistry 
 was first divorced from mystery, here it first passed the narrow 
 confines of a mere handicraft and earned for itself the right to 
 be classed among the learned and liberal jirofessions. 
 
ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 GtORGt tVANS, 
 
 49 West 39th St., N. Y. City. 
 
 Modern artificial crown- and bridge-work belongs to the de- 
 partment of dentistry until recently termed " mechanical," but 
 the judgment, skill, and scientific information required place it 
 far above ordinary mechanical dentistrj^ which has sunk to a 
 low estate since the introduction of vulcanite. To such an 
 extent has vulcanite, by reason of its cheapness and ease of 
 manipulation, superseded other materials demanding greater 
 knowledge and skill in their manipulation, as to retard the 
 higher development of prosthetic dentistry, and indeed, to di- 
 vest it, in the hands of those who depend upon the former, of 
 the dignity which should belong to dentistry as a profession. 
 
 But modern crown- and bridge-work, properly understood and 
 properly performed, takes high rank in dental art, and ofiers 
 wide scope for versatility of talent and inventive genius. The 
 varied and complicated cases presenting for treatment frequently 
 suggest to the expert novel contrivances and methods of con- 
 struction and application. Successful practice of crown- and 
 bridge-work depends upon a thorough mastery of the underlying 
 principles, and expertness in the processes involved, governed 
 by sound judgment and perfect candor. The interests of the 
 patient should be paramount to every other consideration, and 
 after a careful examination he should be given an accurate state- 
 ment of the applicability of the system to his case, in respect to 
 usefulness, appearance, durability, and comfort, as compared 
 with other processes and appliances in use. 
 
 Surgical and mechanical operations of the most delicate nature 
 
 2 17 
 
18 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 are required. Nothing, indeed, in dentistry demands finer ma- 
 nipulation. A practical consideration of the subject will show 
 that a knowledge of anatomy, pathology, and therapeutics, and 
 as well mechanical and artistic skill, are necessary to the correct 
 treatment of cases and the proper performance of the operations 
 indicated. Among the principal steps in an operation may be 
 named, first, the preparatory treatment of the natural roots and 
 teeth for the final process, involving the diagnosis of present or 
 probable lesions and the prescription of whatever remedial or 
 prophylactic measures may be needful ; second, in crown-work, 
 the adaptation of the artificial crowns to the cervical portion of 
 the natural roots and the contiguous membranes, and the restora- 
 tion of the articulation and the anatomical contour; and, in 
 bridge-work, the selection of suitable teeth or roots for founda- 
 tion piers or abutments, and the choice and adaptation in con- 
 structive practice of the forms which will insure the highest 
 degree of stability and best sustain the force of occlusion, thereby 
 avoiding abnormal positions and conditions. 
 
 The practice of crown- and bridge-work by dentists possessing 
 the requisite attainments and governed by correct ethical prin- 
 ciples gives results which will establish its value, remove erron- 
 eous impressions, and insure a wide professional and public 
 indorsement of this important branch of prosthetic dentistry. 
 Its ■ extraordinary facilities for preserving and replacing teeth 
 arc graduall}^ making for it the position in dental art which it 
 merits. 
 
PAET I. 
 
 PREPARATORY TREATMENT OF TEETH AND ROOTS FOR 
 
 CROWN-WORK. 
 
PREPARATORY TREATMENT OF TEETH AND 
 ROOTS FOR CROWN-WORK 
 
 Preparatory treatment of teeth and roots for crown-work 
 includes, in addition to the shaping required to fit them for the 
 reception of the crowns, the bringing about of the healthiest 
 possible condition in the teeth and roots and the adjacent parts, 
 as the cure of existing lesions, the removal of calculus where 
 necessary, and the adoption of such measures as shall prevent 
 the recurrence of old troubles or the inception of new. 
 
 Notwithstanding all that advanced knowledge of therapeutical 
 agents and skill in their use permit, there are many teeth and 
 roots which cannot be rendered suitable for the successful appli- 
 cation of crown- or bridge-w^ork. Roots which are permeated 
 and softened by decay, exposed or loosened from absorption of 
 the gums and alveoli, or aftected with irremediable disease of 
 the investing membranes, should be thus classed. Cases in 
 which abscess with necrosis has extensive!}^ impaired the walls of 
 the alveoli are equally intractable. 
 
 Experience shows that the results in this department of den- 
 tistry depend largely upon diathesis or constitutional tendency 
 and upon the attention given to the preservation of the health 
 of the mouth ; and these conditions should be carefully estimated 
 in the selection of a system of treatment and the method of its 
 application. 
 
 •21 
 
CHAPTEE I. 
 
 THE PULPS OF TEETH— THEIK PEESEPvVATION OR DEVITALI- 
 ZATION. 
 
 The preservation of the vitality of the pulps of the teeth is a 
 matter of as much importance in connection with crown- and 
 bridge-work as in any other class of operations, though the 
 excision of natural crowns for the purpose of utilizing the roots 
 as abutments for bridge-work is extensively practiced, and 
 is defended on the theory that the vitality of the dentine is main- 
 tained by the cementum after the extirpation of the pulp,^ 
 
 Dr. C. F, W. Bodecker, discussing the subject of the " Dis- 
 tribution of Living Matter in Human Dentine," says,^ — 
 
 "• 1st. The dentinal canaliculi are excavations in the basis-sub- 
 stance of the dentine, each containing in its center 2^ fiber of 
 
 ^Dr. J. L. Williams says, " The life and vitality of the cementum remain in- 
 tact and uninjured, and even the dentine may, and undoubtedly does, retain a 
 certain amount of vitality, for something analogous to a healing process takes 
 place at the ends of the broken fibrillse next to the pulp-chamber, and by one of 
 those wonderful provisional conditions, which we so often meet with in the 
 economy of the animal kingdom, nature reverses or changes the origin of nutri- 
 tive supply, and the material for maintaining the continued vitality of the den- 
 tine comes through the cementum." 
 
 He further says, " Every practicing dentist has observed that a tooth which is 
 removed from contact with the fluids of the mouth changes color. This change 
 in color is largely the result of the evaporation of the water from the organic 
 portion of the tooth. Now, if the apical foramen of such a tooth be clo.«ed, and 
 the tooth be then placed in water, or preferably, glycerin and water, in a short 
 time it will regain nearly its original color, and at the same time it will be found 
 that it has increased in weight. This means, of course, that the entire tooth has 
 absorbed from the surface a certain quantity of the fluid, and this fluid has pene- 
 trated every part of the solid structure of the tooth. Will any one doubt, with 
 these facts in view, that when the tooth is in position in the jaw, and surrounded 
 by all the delicate adjustments furnished by nature, there may be a circulation 
 of nutrient fluids throughout the entire root after the removal of the pulp ?" 
 
 It is difficult to understand how a f aturation can be compared to an infiltration 
 controlled by vital circulation. — G. E. 
 
 '^Dental Cosmos, vol. xx, page 6-')G. 
 22 
 
DEVITALIZATION OF THE PULP. 27 
 
 remains in the tubuli, and increases the difficulty of producing 
 an aseptic condition of the dentine. It is asserted that arsenic 
 produces devitalization of the fibrillfe as far as the cementum, 
 and, in some cases, even involves that tissue, while in instanta- 
 neous extirpation of the pulp the vitality of the dentine is to 
 some extent preserved by the circulation it receives from the 
 cementum. 
 
 Practical experience, however, shows that instant devitaliza- 
 tion or extirpation is the most satisfactory in general and final 
 results. Arsenic, when used, should be applied directly to the 
 pulp in the smallest quantity possible to effect its devitalization, 
 and securely sealed in the cavity. The application should be 
 kept in position no longer than is necessary to effect the devitali- 
 zation of the pulp. 
 
Plate IV. 
 
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CHAPTER III. 
 
 PULPLESS TEETH,— THEIR TREATMENT AND DISINFECTION. 
 
 Pig. 4. 
 
 The treatment of pulpless teeth or roots consists in as thorough 
 a performance as possible of the following operations : 
 
 1st. Removal of the contents of the canals. 
 
 2d. Disinfection of the root-canals and the dentine, and the 
 establishment of permanent aseptic conditions by mummification 
 of the contents of the tubuli. 
 
 3d. Closure of the apical foramen. 
 
 A knowledge of the usual positions of the root-canals in the 
 different teeth is essential for a generally successful performance 
 of these operations, which are greatly facilitated, in crown- work, 
 by the ease with which direct access to the 
 root-canals is obtained. (See Plate IV.)^ An 
 opening is first made into the center of the 
 pulp-chaml)er in a line with the root-canals 
 sufficient to give free and direct access to 
 them, and any remaining portion of the pulp 
 removed with broaches. The canals are then , 
 guided by frequent explorations with a fine 
 probe, carefully enlarged with Gates-Glidden 
 drills (Fig. 4). At least three sizes — large, 
 medium, and small — of drills each for the 
 right-angle and the direct hand-piece are required.* Very little, 
 if any, pressure should be put upon them when in motion, as they 
 will move forward of themselves. Under pressure a false passage 
 
 1 Plate IV. — Figs. 1 and 2 represent the superior and inferior teeth in trans- 
 verse section through the base of the pulp-chamber in the crown, showing the 
 entrance to the root-canals. 
 
 Figs. 3 and 4 represent the superior and inferior teeth in transverse section 
 through the root-canals as they diverge from the pulp-chamber. 
 
 aa, bb, cc, dd, Jt\ dd, and ee, Figs. 3 and 4, show the relative shapes, whether 
 circular, oval, or flattened, of the root-canals in the teeth they severally repre- 
 sent. 
 
 29 
 
30 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 in a curved root is possible, or the small drill might be broken 
 oif or forced through the apical foramen with disastrous conse- 
 quences, where alveolar abscess did not exist. ISTeither should 
 
 Fig. 5. 
 
 Fig. 6. 
 
 Fig. 7. 
 
 they be forced into canals closed by calcification. A slight pain 
 is usually experienced when they enter the zone of sensibility 
 formed by the cementum which composes the end of the root. 
 The probe-like points of these drills do 
 not cut, but simply guide the drills, and 
 confine them to the line of the canal. 
 The use of these drills is condemned 
 by some for reasons attributable to their 
 careless or improper employment, but 
 they are indorsed, in experienced hands, 
 for their adaptability to the w^ork under 
 consideration. 
 
 The cavity of the root-canal having 
 l)een properly opened up and its con- 
 tents removed, it is syringed out with 
 tepid water, and, in case the pulp has 
 been long devitalized, wdth peroxide of 
 I Ivydrogen, and then dried with cotton. 
 The mouth is then properly protected 
 with napkins, and a current of hot air 
 introduced into the pulp-chamber by a 
 hot-air syringe (Fig. 5), at a tempera- 
 ture higher, as it leaves the nozzle, than is comfortable for the 
 finger. This heats any part of the crown remaining, and the 
 lower portion of the root. A silver probe, connected wdth an 
 oval-shaped mass of silver or copper (Fig. 6) which has been 
 heated to a dull red heat, is then introduced into the root-canal 
 
TREATMENT OF PULPLESS TEETH. 31 
 
 (Fig. 7). As silver possesses remarkable properties as a ther- 
 mal conductor, the heat is transmitted to the point of the probe 
 very rapidly.' The probe being inserted as far as possible up 
 the canal, the patient is directed to raise the hand as a signal 
 should the heat cause pain, when the probe must be moved up 
 and down, or withdrawn for a moment. This procedure, follow- 
 ing the previous application of hot air with the sj'ringe, evapor- 
 ates the moisture and gases from the root-canals and the open 
 ends of the tubuli. The heat also acts as a germicide,^ and car- 
 bonizes any organic matter the instrument reaches. While in 
 this heated and dried-out condition the dentine is saturated with 
 an antiseptic agent, which should possess such properties as to 
 make its action efiicient and its effects permanent. At present, 
 experience finds bichloride of mercury — ^-^ solution — or iodo- 
 form most suitable for the purpose.'^ When both agents are 
 used, the sublimate solution should be applied first, then the 
 iodoform, after the canal has been dried. Iodoform is most 
 convenienth' applied in a saturated solution in sulphuric ether. 
 Carbolic acid and like agents are being discarded for various 
 reasons, among which are their inefficiency and their eventual 
 absorption from the dentine. 
 
 After one or more treatments in the manner described, the 
 canal is dried and the foramen closed. Of the man}- materials 
 used for the purpose, gutta-percha is most approved. When 
 used in the form of chloro-gutta-percha, a good method is to dip 
 a few shreds of cotton in the solution, press out the surplus, and 
 gently pack (not push) them lengthwise into the extremity of the 
 canal. Cotton so prepared is incorruptible, and when properly 
 inserted it effectually closes the foramen, obviates any danger of 
 
 ^ As a test of the thermal conductivity of silver, heat the oval portion of this 
 instrument to a dull red heat, and place the point of the probe, which is as fine 
 as a broach, in a little water on the end of a cork. The water will boil and 
 evaporate in a few seconds. 
 
 2 To accomplish the same end, Dr. Register uses fine tubes of platinum, through 
 which hot air is forced, but this is hazardous near an open foramen, less efl'ective, 
 and less convenient than the method detailed. 
 
 ■' lodol or the dental tincture of iodine can be used in place of iodoform should 
 the odor of the latter render it objectionable. A small quantity of oil of %vinter- 
 green added to the solution aids in disguising the odor. 
 
32 ARTIFICIAL GROWN- AND BRIDGE-WORK. 
 
 air or the solution of gutta-percha being pressed through, and is 
 easily removed should any subsequent condition require it. The 
 canal is then filled with gutta-percha or any other material 
 preferred. Ordinary gutta-percha should be used to close a 
 foramen when an abscess has just been treated by injecting 
 throuo:h it. 
 
 Successful treatment of pulpless teeth depends not on " imme- 
 diate root-filling after extirpation of the pulp," hut upon imme- 
 diate roof-Jjlliiig after producing a thorough aseptic condition of the 
 canals and dentine. 
 
 Ample room should be left in any root-canal which is to 
 receive the post of a crown, as any part of the canal not occu- 
 pied by the post will be filled by the retaining material. 
 
 A pulpless tooth presented for crowning, the roots of which 
 have been treated and filled in some previous operation, should 
 be carefully examined, and if any doubt is entertained as to its 
 hygienic condition it should receive the antiseptic treatment 
 above described, as the ultimate success of crown-work depends 
 largely upon the thoroughness of these preliminary operations. 
 
CHAPTER IV. 
 
 CHRONIC ALVEOLAR ABSCESS. 
 
 Many teeth and roots presented for erown-work are affected 
 with chronic alveolar abscess. A general description of an 
 effective method of treatment is therefore properly associated 
 with a discussion of the subject. 
 
 The cause of chronic alveolar abscess will be found in a con- 
 tinuation of those conditions which originally produced the acute 
 form. The tooth or root being pulpless, septic gases, generated 
 by the decomposition of organic matter in the root-canal and in 
 the tubuli of the dentine, find an outlet through the open foramen 
 into the apical space, causing pericementitis and formation of 
 pus. The general treatment consists in the removal of all septic 
 matter and gases from the root-canal and dentinal tubuli, the 
 destruction of the pus-sac, the application of suitable therapeutic 
 agents, and the adoption of measures to prevent further formation 
 of pus. 
 
 Chronic alveolar abscess is usually found in the following 
 forms : 1st. Abscess with a fistulous opening in the gum, and 
 accessible through the root-canal and foramen of the root. 2d. 
 Abscess, with fistulous opening but not accessible through the 
 apical foramen. 3d. Abscess from which pus discharges through 
 the apical foramen and root-canal with no opening through the 
 gum. 
 
 In the* treatment of abscess of the first form, the canal should 
 be enlarged as described in the treatment of pulpless teeth, and 
 the foramen opened, if possible, with a smooth broach without 
 the use of a drill. Tepid water is then forced through the 
 foramen with a fine-pointed syringe (Fig. 8) introduced well up 
 the canal, and packed in with gutta-percha, or pumped up with 
 cotton on a broach until it passes into the abscess and out 
 
 3 83 
 
34 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 through the fistula. Peroxide of hydrogen is next used in the 
 same manner, until it ceases to foam as it passes from the abscess. 
 Aromatic sulphuric acid, either pure or diluted, is then applied 
 as a germicide and powerful astringent. 
 
 In abscesses of the second form, where it is impracticable to 
 treat through the foramen, the canal should he thoroughly disin- 
 fected, and a direct opening into the abscess effected by the track 
 of the fistula, enlarging it if necessary. The abscess should 
 then be thoroughly injected with peroxide of hydrogen and 
 afterwards with aromatic sulphuric acid, by introducing the fine 
 point of a syringe into its deepest parts. The fistula must be 
 
 kept open by inserting in it, at each 
 injection, a strand of twisted cotton 
 saturated with oil of cloves, the pa- 
 tient being directed to remove it in 
 a few hours, or the next day, for 
 which purpose the end should be 
 left protruding. When the apical 
 foramen is open, one injection is usu- 
 ally sufi&cient to cure an abscess ; but 
 when the foramen is closed and the 
 abscess is treated through the gum, 
 several injections are sometimes ne- 
 cessary. 
 
 In case of " blind abscess," first 
 clean and disinfect the root-canal, 
 then at intervals inject the abscess 
 through the foramen with peroxide of hydrogen until the for- 
 mation of pus ceases, placing cotton saturated with oil of cloves 
 loosely in the canal to exclude foreign substances. Should this 
 treatment fail, an opening through the gum into the abscess must 
 be obtained either with a lance and drill, or a trephine, and the 
 same course pursued as in the first form of abscess. 
 
 An entrance into the apical space can be made almost pain- 
 lessly in the following manner, as described by Dr. G. V. Black:' 
 " The mucous membrane is first dried at the point at which it is 
 desired to make the opening, and napkins are so placed as to 
 
 ^ American System of Dentistry, vol. i, page 928. 
 
CHRONIC ALVEOLAR ABSCESS. 35 
 
 keep it dry. Tneu a plugging-iustrument with fairly sharp 
 serrations and of convenient shape is selected. The point of 
 this is dipped into a 95-per-cent. solution of carbolic acid, and a 
 drop convej'ed to the mucous membrane ; this will at once pro- 
 duce a white eschar. Then a slight scratching motion with the 
 serrated point is begun, with the view of removing the tissue 
 that is whitened. This is continued until the carbolic acid is 
 thick with the debris of the tissue torn up, then it is dried out 
 and another drop added, as before, and the process continued. 
 This is repeated as often as may be necessary, going deeper and 
 deeper into the tissue in the desired direction until the bone is 
 laid bare. Then a fresh drop of the acid is placed on the bone 
 and the periosteum carefully raised over a sufhcient space ; then 
 with a sharp chisel cut through to the peridental membrane. 
 This Avill generally cause some pain and some bleeding, but 
 after giving a little time for this to cease, and adding more of 
 the acid, the apical space can usually be reached without diffi- 
 culty. Xo blood should be drawn at any time during the opera- 
 tion, except in penetrating the wall of the alveolus. In doing 
 this no tissue is removed until it is anesthetized by the carbolic 
 acid. This is a little tedious, but it is almost painless, and the 
 general effect is usually better than by other modes of penetrat- 
 ing the apical space. The carbolic acid has the effect of modi- 
 fying the pain, and the opening left does not close so readily.'" 
 
 After the abscess has been cured, the root-canals are treated 
 and tilled as described on page 29. 
 
 In place of aromatic sulphuric acid, if preferred or should the 
 case suggest it, either carbolic acid, the sublimate solution (3-J5VD")' 
 or any other suitable therapeutic agent can be used, but most of 
 them will be found less prompt and less effective, especially if a 
 slightly necrosed state of the wall of the alveolus exists.^ 
 
 Amputation of the Apex of a Root. — In long-neglected alveolar 
 abscess, the pus-cavity occasionally involves the alveolus in such 
 a way as to destroy a considerable portion of the pericementum 
 
 ^For an extensive consideration of this subject the reader is referred to Dr. J. 
 X. Farrar's articles on " Sulphuric Acid v. Creasote in Treatment of Alveolar 
 Abscess," commencing Dental Cosmos, vol. x.\, No. 7, and Dr. G- V. Black's 
 article in the " American System of Dentistry," vol. i, page 929. 
 
36 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 9. 
 
 of the end of the root. The cementum of that part is conse- 
 quently devitalized, and the portion of the root affected becomes 
 degenerated in structure, and saturated with septic matter. In 
 this condition it acquires the character of a foreign substance, 
 proves a constant source of irritation, and defies all efforts of the 
 membranes to perfectly inclose or encyst it. 
 
 In such cases amputation of the portion of the 
 root which is denuded of pericementum is the 
 best course to pursue. An opening is made in 
 the soft tissues above the affected part with the 
 lancet or trephine, and gradually enlarged with a 
 tent of lint or cotton until the diseased territory 
 is fully exposed (Fig. 9), when the devitalized end 
 of the root and any necrosed bone in the territory 
 are removed with a fissure-drill, and the end of 
 the root smoothed. The root-canal is then closed 
 with gutta-percha passed through from within, the 
 surplus being trimmed ofl" on the outside. Cocaine 
 can be used in this operation. 
 The orifice of the cavity in the gum should be kept open until 
 the cavity is filled by granulation. When the healing process is 
 completed, crown-work can be proceeded with. 
 
 The amputation of roots requires skill and experience, and 
 had better be confined to the incisors and cuspids. 
 
CHAPTEE V. 
 
 SHAPING TEETH AND KOOTS FOR CROWN-WORK. 
 
 The principles governing the process of shaping a natural 
 crown or root for any style of artificial crown with a collar 
 attachment require that the cervical portion of the natural crown 
 and root should be given a form that has longitudinally-parallel 
 sides gauged to the line of the periphery of that part, and that 
 any of the coronal section present below it shall be reduced at 
 least sufficiently in size to come within this line. Such a form 
 is necessary to admit of a perfect adaptation of the collar. 
 
 The coronal section of a natural crown to be prepared is 
 usually first ground on the occluding surface with as large a 
 conindum-wheel as the case will conveniently admit (Fig. 10). 
 
 Fig. 10. 
 
 Molars and bicuspids for all-gold crowns should have enough 
 substance removed to make a small space between them and 
 the antagonizing teeth. The approximal surfaces are removed 
 straight from the cervical border to the occluding surface, using 
 rubber and corundum disks (Fig. 11) and tiles, and last of all, 
 as injury to the approximal teeth is then more easily avoided, the 
 labial and palatal portions, for which small corundum points 
 (Fig. 12) and wheels are best adapted. The corners are then 
 rounded. The cervical portion, which includes the junction of 
 the dentine and enamel, is trimmed so that the sides as illus- 
 trated at A, Fig. 13, are level and parallel with the line of the 
 
 37 
 
38 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 root, and as deep as the collar is to be placed (Fig. 14). For 
 this purpose, small corundum points, trimmers, and files can be 
 used. Fig. 15 illustrates a drill, which in the ordinary hand-piece 
 
 Big. it. 
 
 Fig. 12. 
 
 or in the right-angle attachment will easily and quickly accom- 
 plish this. Fig. 16 illustrates another form which can be used in 
 a hand socket, or by revolving it rapidly with the engine. The 
 points should be tempered very hard ; files shaped as shown in 
 Fig. 17 are useful in rounding angular portions. 
 
 In pulpless teeth, the use of excising forceps should be avoided 
 unless the parts admit of it without serious shock to the root. 
 The best plan is to make a succession of holes across the portion 
 to be removed with a spear-shaped drill, and then cut between 
 
 Fig. 1?.. Fig. 14. Fig. 15. Fig. 16. Fig. 17. Fig. 18. Fig. 19. Fig. 20. 
 
 I 
 
 the holes with a fissure-bur or corundum disk, which will permit 
 of easy removal of the part (Fig. 18). 
 
 In preparing incisors and cuspids for gold collar crowns with 
 porcelain fronts, where the pulp is to be preserved, the labial 
 surface and incisive edge should be ground down as much as 
 possible without exposing the pulp or subjecting it to irritation ; 
 the palatal portion at an angle from the cervical border to the 
 incisive edge, enough to level its prominences of contour and 
 
SHAPING TEETH AND ROOTS FOR CROWN-WORK. 
 
 39 
 
 form a slight space between it and the antagonizing teeth (Fig. 19). 
 Pulpless incisors and cuspids should be ground to the margin 
 of the gum at the labial portion, and slightly above the margin 
 on the posterior half (Fig. 20). Bicuspids which are to have 
 porcelain fronts are given the same general form (Fig. 21). 
 
 Bicuspids and molars with or without pulps, for all-gold crowns, 
 should have as much of the natural crown left as possible, as it 
 offers a form of attachment for the artificial crown which is 
 more secure and more convenient than is attained by any other 
 method (Figs. 22 and 23). 
 
 For the porcelain system, incisor, cuspid, and posterior roots 
 are usually ground level with the margin of the gum. The palatal 
 
 Fig. 21. 
 
 Ftg. 22. 
 
 Fig. 23. 
 
 Fig. 24. 
 
 portion is favored in some cases by leaving it a triiie above the 
 margin. The root-canal is shaped to the form of the post or pin 
 so that it shall fit it tightly. For details see the articles on the 
 Bon will and Logan crowns. The occluding edges or surfaces of 
 antagonizing teeth should be removed sufficiently to allow ample 
 space for the artificial crowns or to favor them in the act of occlu- 
 sion. Corundum or composition wheels or points should be kept 
 wet and cool in these and other operations in the mouth. 
 
 Special Preparation of Badly Decayed Teeth or Hoots. — The tem- 
 porary exposure of the end of a root or of the cervical portion of 
 a crown for the purpose of facilitating or simplifying a crowning 
 operation, especially in the adaptation of a collar or band, is 
 ettected by inserting in the ])ulp-chamber or the root-canal a 
 piece of gutta-percha large enough to admit of a portion being 
 brought over against the investing membranes, to compress them 
 for a day or more. Where a secure attachment for the gutta- 
 percha cannot be obtained, a plug of wood should be inserted 
 
40 ARTIFICIAL CROWN- AND BRIDOE-WORK. 
 
 temporarily in the root, and the gutta-percha held in position bj 
 being packed around it. The root can thus be exposed to the 
 border of the alveolar process if desired. In bicuspids and 
 molars, when decay extends up on the cervix farther than will 
 the edge of the artificial crown or the collar, the gums should 
 be pressed up with gutta-percha, the decay removed, retain- 
 ing-pits for a filling made, and the cavity filled with amal- 
 gam shaped to the contour of the tooth (Fig. 24). In incisors 
 and cuspids, when extensive decay has destroyed a portion 
 of the side of the root, a tight-fitting tube made of a metal to 
 which amalgam will readily adhere, and of such size as will ad- 
 mit the pin of the crown, can be inserted up the root-canal and 
 the upper end cemented in with oxyphosphate and the lower 
 with the amalgam forming the filling on the side of the root. In 
 Fig. 25. Fig. 26. Fig. 27. 
 
 Ui 
 
 such a case, the pin supporting the crown should be tapered at 
 the end, and inserted in the canal as deeply as possible beyond 
 the end of the tube. Additional strength is thus obtained ])y 
 a distribution of the leverage along the whole line of the root. 
 
 When a gold cap-crown is to be adjusted on a badly broken- 
 down tooth or root, a post of silver or iridio-platinum wire should 
 be formed to fit the root-canals as shown in Figs, 25, 26, and 27, 
 with a piece of silver soldered crosswise. The post should then 
 be barbed and the point first fastened in the root with a little 
 oxyphosphate, and the crown portion built down about two-thirds 
 of its length with a quick-setting amalgam. This when hard 
 should be shaped and then roughened to furnish a better at- 
 tachment for the cement with which the cro^vn is set. Screws 
 can be used as posts to support the amalgam if preferred. As 
 the artificial crown hermetically covers all the amalgam, the ex- 
 isting prejudice against its use cannot apply to this method. 
 
PART IL 
 
 ARTIFICIAL CROWN-WORK. 
 
ARTIFICIAL CROWX-WORK. 
 
 Artificial cro\vn-work affords extensive facilities for restoring 
 the crowns of natural teeth, and furnishes means of support for 
 bridge-work. 
 
 Two general systems are presented — the porcelain and the gold. 
 The porcelain system includes porcelain crowns with metallic 
 attachments, Avith or Avithout collars, and the gold system gold 
 crowns with porcelain fronts. 
 
 13 
 
THE PORCELAIN SYSTEM. 
 
 CHAPTER I. 
 
 PORCELAIN CROWNS. 
 
 Porcelain crown-work is practiced by many dentists almost 
 exclusively, excepting only the occasional insertion of a gold 
 cap-crown on a posterior tooth. The reasons for this are, the 
 intricate character of the construction of gold crowns, and the 
 objection to crowns with bands or collars. 
 
 The advocates of the all-porcelain system claim for it natural 
 appearance, restoration of contour, strength, and cleanliness, 
 together with simplicity of construction and easy adaptation and 
 attachment to the root, to which the crown is hermetically sealed. 
 
 Porcelain crowns are made in two general styles. In one 
 the crown is attached to the root by a pivot, post, or screw, 
 one end of which is cemented in the root and the other in the 
 crown. Such are the Bonwill, Gates, Foster, How, and Howland 
 crowns. In the other style, one end of the pivot, or post, is 
 baked in the porcelain when the crown is made, and the other 
 end cemented into the root when the crown is adjusted. The 
 Logan, Brown, and new Richmond are of this class. 
 
 Special advantages are claimed for each of these several forms 
 of crowns. A o-eneral knowledo;e of the different methods is 
 therefore essential to determine the adaptation of each to the re- 
 quirements of a case. 
 
 The preparatory treatment of the roots respecting the process 
 of grinding, trimming, and shaping, is nearly the same for all 
 porcelain crowns. Exposing the end of the root, by pressing the 
 44 
 
THE BON WILL CROWN. 
 
 45 
 
 gum awaj from it with gutta-percha preliminary to the operation, 
 will greatly assist the operator, by enabling him to avoid acci- 
 dental laceration of the adjoining membranes, and the annoyance 
 attending their bleeding, besides permitting him to carefully 
 study the adjustment and cementation of the crown. Crowns in 
 which the post is cemented will first be described. 
 
 THE BONWILL CROWN. 
 
 This crown, being one of the first introduced in improved 
 porcelain crown-work, has been very extensively used. The 
 process of its adjustment and insertion is explained in a lengthy 
 article by its inventor and advocate. Dr. W. G. A. Bonwill, from 
 which the following is presented : 
 
 " These all-porcelain crowns have three distinctive features, 
 a concave or countersunk base ; a triangular opening from the 
 base to a point at or near the cutting-edge of the incisore, the 
 base presenting to the labial surface (at its upper portion this 
 groove is enlarged) ; a peripheral margin or border resting 
 perfectly flat on the root, the concavity of the base on the palatal 
 side being at a much more acute angle than on the approximal 
 sides. An anchorage is made in the incisors by a depression or 
 undercut between the labial and palatal surfaces, opening on the 
 latter. In the bicuspids and molars the retaining-pits are nearer 
 the grinding-surface. 
 
 Fig. 28. Fig. 29. 
 
 Fig. 30. 
 
 Fig. 31. 
 
 Fig. 32. Fig. 33. Fig. 34. 
 
 Fig. 2S. — Sectional view of an incisor crown, from mesial side, showing the undercut at the 
 point opening on palatal surface, the conical base, and the opening from the same to the retain- 
 ing-grooves, with the e.xact relations. 
 
 Fig. 29.— Palatal view of same tooth, a is the external opening for egress of alloy and for 
 packing around the pin. The dotted lines show the recess or undercuts on the mesial and distal 
 sides and near the point for retaining the crown, and its relation with the conical ba.se. 
 
 Fig. 30. — (rrinding-surface view of a superior molar with the countersunk pin-holes on the 
 buccal and palatal sides. 
 
 Fig. 31. — Same view of an inferior molar with the pin-holes on the mesial and distal sides. 
 
 Figs. 32 and 33. — Sectional view of a molar and bicuspid crown, showing the countersinks 
 and their relations with the conical base. 
 
 Fig. 34. — Sectional view of an incisor root, showing the ret.aining-cuts made by the wheel-bur 
 shown in Fig. 41. 
 
46 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 " It is not necessary that the face of the root should be flat ; it 
 may be either concave or convex. The concave base of the 
 crown prevents the amalgam from escaping under the heavy 
 pressure exerted to force it into position, and in impacting the 
 amalgam and expressing the mercury. It allows of a dense 
 body of material around the metallic pin, giving the equivalent 
 of a pin the whole diameter of the base of the crown. It 
 leaves no joint, the crown and root being continuous. The 
 amalgam is so thoroughly hardened at once by impaction in the 
 double concave of crown and root as to make a very firm opera- 
 tion. It prevents any possibility of the crown's twisting upon 
 Fig. 35. Fig. 37. Fig. 38. Fig. 39. Fig. 40. Fig. 41. 
 
 Fig. 36. 
 
 Fig. .3.5.— End view of a canal prepared for the improved combination-metal pin. 
 
 Fig. 36. — End view of same canal as in Fig. 35, prepared for a triangular pin, showing how 
 much more of the mesial and distal surfaces have been cut away from it than in Fig. 'io for the 
 improved pin. 
 
 Fig. 37. — Sectional view of an incisor crown and root, with the improved pin in its relative 
 position to each.i with the depressions made by wheel-bur. 
 
 Fig. .38. — Sectional view of a superior molar, with the large angular pin in palatal root and 
 two square pins in the buccal roots, one being shorter and not passing through the crown. 
 
 Fig. 39.— Block of a molar and bicuspid, showing the countersunk holes for pins in the molar, 
 and the hole in the mesial side of the second bicuspid where a pin is alloyed in and set into a 
 decayed cavity in the distal surface of the first bicuspid, being held upon the molar roots and 
 attached to the bicuspid by the alloy. 
 
 Fig. 40.— Side and end view of the largest size angular combination -metal pin with the 
 stamped serrations.- The square pins are without serrations and double-pointed, made of the 
 same metal and of equal thickness throughout. 
 
 Fig. 41.— The smallest-sized wheel-bur for grooving the canals for anchoring the pin and alloy. 
 
 1 The sectional views of the incisor and molar, giving the relative position of 
 the pins in the crowns and roots, should show pins of larger size. The pins as 
 furnished should be filed down but little. It is not absolutely necessary that so 
 many serrations should be made in the canals by the wheel-bur for retaining the 
 amalgam and pin as are shown in the sectional view of the root of an incisor. 
 While no serrations are shown in the roots of the molars, it is understood that all 
 the canals must have the serrations. The square pins in the canals need no serra- 
 tions. At the point where they occupy the countersink in the crowns, make two 
 or three very slight cuts on the edges with a sharp file. The ends can be left blunt. 
 
 2 These pins are now made without serrations. When amalgam is used for se- 
 curing them, they become amalgamated and firmly united. 
 
THE BON WILL CROWN. 47 
 
 the pin and root. In the event of fracture of the crown, the 
 convex surface of amalgam on the root makes the substitution 
 of a new crown an easy operation. It enables the operator to 
 fit the crown in much less time ; it allows a proper position to 
 be given to the pin, with less danger of fracture therefrom; it 
 permits of a larger quantity of amalgam in the crown, and is 
 capable of bearing greater strain; it makes the permanent suc- 
 cess of the operation probable, from the fact that it is absolutely 
 jointless, and secures immediate solidity, even while the amal- 
 gam is semi-plastic. These crowns are capable of resisting the 
 force of biting or mastication, because they are supported nearly 
 to the cutting-edge or grinding-surface, the triangular opening 
 from the concave base nearly to the cutting-edge allowing the 
 pin to be imbedded in the labial face of the crown where there is 
 the greatest amount of porcelain. 
 
 " The amalgam to be used as the medium of union must set 
 quickly and l)e very hard. Thus far I have found nothing better 
 than the alloys I have specially prepared for this line of work, 
 and, though they are costly, the superior results obtained by 
 their use amply repay the cost. I use ISTo. 1 generally. If mixed 
 tliick, it will set so quickly that the operator must work rapidly 
 to prevent its being wasted. In incisor cases I use No. 3 at the 
 gum line, and make a close joint. 
 
 " The simple device which I have called an adjuster^ is a very 
 useful adjunct in the operation. It requires considerable force 
 to set one of these crowns according to directions, — a force which 
 cannot be applied with a mallet without danger of loosening or 
 displacing the crown. Steady pressure with slight rotation will 
 carry the crown into place, if the amalgam is not too hard or 
 there is not too much of it. I would advise you not to attempt 
 to set a crown without one of these adjusters or its equivalent. 
 
 " A crown can be mounted upon almost any root if the alveolar 
 process has not been too much absorbed. 
 
 " It is an advantage in every way to take an impression of the 
 root, either wnth plaster or modeling composition, to get the size 
 and shape of the crown. The articulation b}- a bite in wax is 
 equally important. 
 
 ^ For description, see article on " Cementation." 
 
48 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 " If the patient exposes the gums much in speaking or smihng, 
 the root may be cut down with the bur or corundum-wheel be- 
 yond the free edge to conceal the joint. With bicuspids and 
 molars it is not necessary to go below the gum ; a joint well 
 made will not be observed, and the strength of the root will be 
 preserved. If the root is decayed below the gum, after removing 
 the softened parts, fill it with alloy ; if it be split or have very 
 thin walls, a platinum band can be made separate from the 
 crown. This will seldom be necessary, as the pin, anchored 
 high up in the root, will be its equivalent. 
 
 " In preparing the canal, use first a small-sized, spear-shaped 
 drill, carefully following the natural channel. Then follow with 
 a larger one, taking care not to cut through the root near the 
 apex. On the mesial and distal sides cutaway but little, as there 
 is where fractures are most liable to occur. The canal can be 
 very tapering and yet hold the pin, if the undercuts or grooves 
 are well made all along the walls from the apex out. There 
 need be but very little space around the pin. The mouth of the 
 root should be countersunk the same as the base of the crown, 
 in order that the amalgam may extend to its very edge, leaving 
 no dentine exposed. The smallest-sized wheel-bur may be used 
 to make an interrupted female thread at various points along the 
 canal to hold the amalgam. By all means save all the walls of 
 the root possible. The face of the root may be fiat or concave, 
 according to indications. In most cases it had better be fiat. 
 
 " The crown to be inserted should be inspected closely, as the 
 retaining undercut in the incisors and the depressions in the bi- 
 cuspids and molars may not be well defined. If not, the crowns 
 are Hable to work loose. If the base has been ground off" in fit- 
 ting, the edges should be beveled again to a fine margin with a 
 corundum-point. The crown should be fitted to the root in 
 the mouth, not to the plaster cast. The articulation should be 
 clear, to avoid displacement. The pin should be as large as the 
 previously prepared canal will admit. The pin must in every 
 case be fitted, and in fitting it file only on the plain sides. The 
 serrations in the large pins need not be touched. Leave the end 
 sharp, to offer the least resistance in passing through the amal- 
 gam. The end of the pin to be passed into the crown needs 
 
THE BON WILL CROWN. 49 
 
 very little alteration. The crown being open on the palatal sur- 
 face of the incisors, permits a blunt-pointed pin to go up to its 
 place. The niiddle of the pin should not be interfered with if it 
 can be avoided. It is well to cut the pin a little short for in- 
 cisors, as it may not get pushed entirely up in the root through 
 the amalgam. The small square pins are used in the bifurcated 
 roots of bicuspids and in the buccal roots of molars. They can 
 be sharpened at both ends, but the outer end will not require so 
 much sharpening. The palatal roots of molars will generally 
 take one of the largest thick pins, with one square pin in the 
 largest and most accessible buccal root. Each canal should have 
 a pin, if the canal can be reached and properly prepared to receive 
 it, even though the pin has to be so short as not to pass through the 
 hole in the crown. If it enters the countersunk base it will sup- 
 port the root. The lower molars will require two of the largest- 
 sized thin pins. As the support of the root is dependent upon 
 the size of the pin and the depth to which it is inserted, the 
 single-rooted teeth should have the very largest thick pin. If the 
 root is thin on the mesial and distal sides, the thin, angular pin 
 is to be preferred. When the pin is thoroughly set it is hard to 
 fracture the root. The crown should go on easily and correctly 
 over the pin, special note being taken of the position of the 
 latter in the canal, so that it mav be returned at the same anffle. 
 Ordinarily these large pins do not have to be bent. If necessary, 
 it had better be done with a hammer, and before the mercurv 
 touches them. The pin should have free movement in both root 
 and crown. Should it be discovered that the pin is too long after 
 it has been packed in the root, it can be cut off with sharp for- 
 ceps, pressing them up against the pin to prevent displacement. 
 It can be sharpened subsequently with the corundum-wheel. 
 
 " To insure an amalgamation of the pin with the tilling, brighten 
 the surface of the former before inserting. In the buccal roots 
 of molars the pins need not be inserted more than a quarter of 
 an inch, or even less, in some cases. 
 
 "The roots, crown, and pins being in readiness and arranged 
 on the table, so that no mistake may occur from getting the pin 
 in the wrong position, and the appliances necessary for the opera- 
 tion being at hand, the alloy preferred should be mixed a little 
 
 4 
 
50 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 thinner than if intended for a filhng, especially where the root 
 has a long canal. The shorter the canal, the thicker the amal- 
 gam may be mixed. Mix only enough at one time for one root. 
 Put enough amalgam in the canal to nearly fill it, but do not 
 pack it ; force a steel pin made for the purpose, of about the 
 same size as the pin, to make way for the easier insertion of the 
 latter. Then grasp the pin with suitable forceps, and carefully 
 but steadily press it up to its destination. If you cannot suc- 
 ceed in doing so, remove it, and again use the steel pin. When 
 in place, use an instrument with a point small enough to pass 
 between the pin and the root, and pack by tamping the amalgam 
 around it. A piece of bibulous paper placed over the point of 
 the instrument will assist materially in carrying the amalgam 
 before it. Before the amalgam has become too hard, replace the 
 crown to determine if the pin is in proper position ; if not, it 
 can be crowded to one side or the other with the tamping-tool. 
 Should the pin be found to be rather long, it can be ground off 
 with the corundum-wheel, holding it meanwhile with the forceps. 
 ISTo attempt should be made to bend the pin after it has been 
 amalgamated, for fear of breaking it. If any amalgam has been 
 left, and it is still plastic, it may be packed around the pin at the 
 base of the root, using the bibulous paper as before directed. If 
 not, mix again to complete the operation. Bank up the amalgam 
 on the root high enough to fill the base of the crown. The crown 
 should now be tried on, and forced home with an adjuster 
 adapted to the case, removing the surplus amalgam if too nmch, 
 or adding if not enough. Remove and dry the crown, and fill 
 up simply the undercut cavity near the cutting-edge if an incisor, 
 or the depressions in the crowns of bicuspids or molars, allowing 
 a very little to extend into the cervical base. JSTow force it home 
 with the adjuster. Free mercury will be squeezed out on the 
 palatal surface, which should be wiped off. Now hold the crown 
 in place with the fingers, with the bibulous paper under the 
 tamping-instrument, and consolidate the amalgam around the 
 point of the pin in the crown, absorbing any free mercury which 
 appears there. The excess of alloy at the joint must now be 
 removed, care being taken to press the crown up while this is 
 being done. The amalgam packed around the pin in the crown 
 
THE HOW CROWNS AND METHODS. 51 
 
 OH the palcital side should be as stiff as may be to work readily. 
 It is well to leave over some of the first mixins^ for holdino- the 
 pin, and this will be about right for consolidating about this 
 point. 
 
 " If in a bicuspid or molar crown the pin should come so far 
 through as to interfere with articulation, it may be ground ofi 
 with the corundum-wheel while the crown is firmly held. 
 
 " The case can now be dismissed, with directions for the patient 
 to return the next day, in order to make sure that the articula- 
 tion is correct and to dress off" the joint between the crown and 
 root, which may be done with a small round-headed bur. 
 
 "• There are some cases in which the root cannot be filled with 
 anything; if in a molar, the pulp-chamber can be relied upon to 
 hold a headed pin or pins. When a tap-hole is required in the 
 root it can be made low down and at an acute angle, and the 
 amalgam packed around the root-canal above the tap. 
 
 " Should an artificial crown be broken, another can easily be 
 substituted, by burring off any excess of amalgam, and using 
 fresh amalgam, mixed thin, to allow of ready adjustment. 
 - " Lower incisor roots, which have hitherto been abandoned to 
 tlie forceps, can be crowned by this process. 
 
 " Two crowns can be inserted on the root of one large molar 
 with the assistance of the decayed approximal surface of an 
 adjacent tooth (see Fig. 39)." 
 
 THE HOW CROWNS AND METHODS. 
 
 These crowns are the invention of Dr. W. Storer How. There 
 are two styles, — four-pin crowns for incisors, cuspids, and bicus- 
 pids, and porcelain dovetail crowns for bicuspids and molars. Each 
 form embraces some novel features. Dr. How's methods, being 
 general in application, are used in inserting other forms of crowns. 
 
 The following are Dr. How's descriptions and illustrations of 
 his methods and crowns : 
 
 " The Four-Pin Crown. — The difficulties and uncertainties in 
 mounting artificial tooth-crowns on roots, by either old or new 
 methods, led me to a careful study of the problem, and resulted 
 in a nearly simultaneous devising of several new forms of 
 crowns and appliances for setting them, as well as a perfected 
 
52 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 42. Fro. 43. Fig. 46. Fig. 47. Fig. 48. Fig. 49. 
 
 method of performing the operation of fixing a peculiar screw- 
 post (Fig. 42) in a root, and also a novel process of attaching 
 Fig 44 ^^^® crown to the post. At present I will describe -p^Q 45 
 simply the four-pin crown (Fig. 43) and the suc- 
 cessive steps to be taken in mounting it. 
 I " 1. When the root is in proper condition for 
 
 mounting, measure the depth of the canal by 
 means of the canal-plugger and its flexible gauge 
 (Fig. 44), and fill the canal at and a short distance 
 from the apex of the root, keeping the gauge 
 at position to show the full length of the canal and 
 also the distance to which it has been tilled. 
 
 " 2. Cut ofii'the root-crown with excising forceps 
 and a round file, down to the gum margin, and with 
 barrel bur ISTo. 241 cut the labial part of the root 
 fairly under the gum without wounding it. 
 
 " 3. Set gauge on a Gates drill (Fig. 45) to one- 
 half the gauged depth of the canal, and drill to 
 that depth. 
 
 " 4. Set the twist drill in its chuck (Fig. 46) to 
 project the same length as the Gates drill, and drill 
 the root to exactly that depth. 
 
 " 5. Enlarge the mouth of tlio canal one-sixteenth 
 of an inch deep all around to near the margin of the r 
 as shown in Fig. 47, using square-end fissure-bur No. 
 and then with oval, No. 94, undercut a groove lingually an 
 the sides. 
 
 H < 
 
 ^ I 
 
 oot, 
 
 59, 
 
 d at 
 
THE HOW CROWNS AND METHODS. 
 
 58 
 
 " 6. If the rubber-dam is to be used for a gold or plastic 
 backing, put it now over the root with Hunter's root-clamp, 
 also over the adjacent teeth, and thoroughly dry the canal. 
 
 " 7. Set the tap in its chuck (Fig. 48) a trifle less in length 
 than the drill, oil the tap and carefully tap the root to the gauged 
 depth. 
 
 " 8. Insert the post in its chuck (Fig, 49) to the exact gauge 
 of the tap, and turn the thumb-screw down hard on the end of 
 the post, then screw the post into the root, release the thumb- 
 screw, unscrew the chuck a half-turn, bend the post until the 
 
 Fig. 50. 
 
 FiQ. 51. 
 
 Fig. 52. 
 
 Fig. 54. 
 
 Fig. 53. 
 
 Fig. 55. 
 
 chuck stands in center line with the adjoining teeth, and unscrew 
 the chuck from the post. 
 
 " 9. Slit the rubber back from adjacent teeth, tucking the 
 flaps out of the way, so that the occlusion may be tried, the 
 post excised and ground ofl" until the teeth close clear of the 
 post. 
 
 " 10. Try the crown on the post, and with disk F grind the 
 rib between the neck pins until the crown is labially flush with 
 the root margin, using the disk dry and cutting a little at a time 
 until exactly flush. 
 
 " 11. Take the crown and place the mandrel (Fig. 50) between 
 the pins just as the post is to be, and with the pliers (Fig. 51) 
 
54 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 bend the pins carefully over the mandrel, cutting off the pins if 
 too long to be pinched in on the mandrel at the sides, observing 
 that the pin nearest the cutting-edge is first to be bent (Fig, 52), 
 and the opposite pin bent below it on the mandrel, and so with 
 the others (Fig. 53). 
 
 "12. Slip the crown over the post, try occlusion, and with 
 the post-chuck bend the post until the crow^n is properly aligned 
 with the teeth, then with a stump corundum-wheel JSTo. 3 grind 
 the neck of the crown to a close labial fit with the root, fitting 
 only the portion to be concealed by the gum, leaving narrow 
 gaps at the sides to be filled by the backing between crown and 
 root (Fig. 54). 
 
 " 13. Grind cutting-edge for occlusion and relation to the 
 other teeth, and be sure that the opposing tooth does not strike 
 the crown, the post, or the pins. 
 
 " 14. Fix the crown on the post by pinching the pins into 
 
 Fig. 56. Pig 57 
 
 the screw-threads in the post with the special pliers for that 
 purpose. 
 
 " 15. Finally, pack the backing of gold, or cement, or amal- 
 gam, or Wood's metal,^ or — for temporary backing while treating 
 abscess — gutta-percha, into all the crevices around the post and 
 behind and under the pins, and between the crown and the 
 root ; contour and finish thoroughly, so that no ledge or other 
 imperfection can be found. 
 
 " Fig. 55 shows in vertical mid-section, an incisor crown 
 mounted on a root; the blackened portions of the backing 
 serving to define clearly the locking-hold of the backing on the 
 screw-post, the crown-pins, and the root recess. 
 
 " Fig. 56 shows in perspective a cuspid crown ready to be 
 
 1 Wood's metal suggested by Prof. J. Taft. 
 
THE HOW CROWNS AND METHODS. 55 
 
 slipped over its post, and also a cuspid crown ready for its post 
 in the bicuspid root, which has its lingual cusp remaining, and 
 Fig. 57 shows these crowns on their posts awaiting tlie com- 
 pleting or contour-backing. 
 
 " When it is desired to contour the backing of a cuspid crown 
 to form an inner cusp, or to adapt a cuspid or incisor crown for 
 masticating uses, the pins nvdy be twisted together over the man- 
 drel, and again twisted tightly over the post as in Fig. 58 ; but 
 in some cases it may be better to bend the neck-pins, as in Fig. 
 59, instead of twisting them. In all cases the bent pins are to 
 be pinched quite hard over the mandrel and post, so that the 
 serrations of the pliers will roughen the pins to prevent their 
 being pulled through the backing, which should also be carefully 
 condensed around the pins and post. 
 
 "When the root is much decayed, the bottom of the cone- 
 
 FiG. 58. Fig. 59. Fig. 60. 
 
 shaped cavity may be drilled and tapped to the depth of a six- 
 teenth of an inch, and the post, thus anchored, may be further 
 secured by cement in the grooved walls of the cavity and around 
 the post (Fig. 60). 
 
 " The screw-posts are made of crown metal, an alloy devised 
 for the purpose in order to obtain a stiff post that will permit 
 the cutting of the peculiar and extremely accurate thread formed 
 upon it, and wliich will not amalgamate or be otlierwise aftected 
 by any backing-material that may be used. Of course platinum 
 or platinum alloyed with iridium may be employed for posts, 
 but the crown metal is in every way superior. 
 
 '' There are some cases of a class which has hitherto presented 
 difficulties that may now be easily overcome b}' gi-inding the 
 
56 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 post flat on the crown side after it has been set and bent in the 
 root (Fig. 61), so as to be clear of the occluding tooth; and then 
 the crown-pins may be bent over the reduced post, the crown 
 fitted and ground to clear the opposing tooth (Fig. 62), and the 
 backing added in completion. 
 
 "A similar case, in which the opposing tooth and a proper 
 alignment require an oblique bending of the pins, is seen in Fig. 
 63, while the reverse arrangement of parts is shown in Fig. 64, 
 The crown is thus seen to be adapted to a wide range of adjust- 
 ments, because its point of contact with the root is at the labial 
 portion of the neck, on which as on a hinge the crown may be 
 
 Fro 61. 
 
 Fig. 62. 
 
 Fig. 63. 
 
 Fig. G4. 
 
 Fig. 65. 
 
 swung out or in (Fig. 65, dotted lines), over an arc of at least 
 sixty degrees, at any point of which it may be quickly and firmly 
 fixed. The labio-cervical junction is made just under the gingi- 
 val margin, and I usually interpose a thin layer of cement, amal- 
 gam, or gutta-percha, or a narrow ribbon or several large blocks 
 of soft gold ; the joint always to be made carefully smooth, and 
 hid from view under the free margins of the gums." 
 
 The Porcelain Dovetail Tooth-Oroum. — These crowns are de- 
 signed for the roots of bicuspids and molars only, and the process 
 of mounting them may be very briefly described. 
 
 " Fig. QQ shows the roots of an inferior molar after the apical 
 portions have been filled, the neck recessed, the canals drilled 
 and tapped, and two How screw-posts firmly fixed therein, the 
 ends of the posts having been pinched towards each other by 
 means of a pair of pliers, so that they will go through the cen- 
 
THE HOW CROWNS AND METHODS. 
 
 57 
 
 tral opening in the crown (Fig. 67). This opening is of a dove- 
 tail form, as shown in cross-section b}' Fig. 68, where the crown 
 is seen in phice over the posts on the root. It is thus made 
 obvious that the crown may be easily put on and off the root in 
 the process of fitting the crown-neck to the root-neck, and also 
 that, for occlusion, the crown may be ground low on any or all 
 sides without destroying the dovetail function of the central 
 cavity. When the fitting is completed, and the crown cut so 
 short as to be -gJ^ of an inch distant from the occluding tooth, 
 amalgam is packed into the neck recess, around the posts, and 
 thinly over the cervical margin of the root, the crown put in 
 place, and, with thumb pressure, firmly seated. Then test the 
 occlusion, and complete the operation by packing amalgam into 
 
 Fig. 66 Fig. 67. Fig. 68. Fig. 69. Fig. 70. Fig. 71. 
 
 the crown opening, which will permit the forcing of the amalgam 
 in all directions, to insure a firm base for the crown, and its 
 secure dovetail attachment to the posts, as shown by Fig. 68. 
 
 " The bicuspid crown (Figs. 69 and 70) is similar]}^ mounted, 
 as may be seen in Fig. 71, cross-section ; the same crown and 
 root being shown in contour by Fig. 72. In some instances this 
 bicuspid crown may, like the Foster crown, be secured b}' a 
 headed screw, as shown in Fig. 73. The root having been 
 drilled and tapped and recessed, and the crown properly fitted 
 and articulated, the screw is put through the crown, amalgam 
 packed in the crown-groove and around the screw, which is then 
 inserted in the root, and the crown pressed hard into its place. 
 The screw is then turned into the position shown in Fig. 73, 
 thus compressing the amalgam or cement in both recess and 
 groove, after which the screw-head may be covered wnth amal- 
 gam, cement, or gold, as desired. 
 
 " As a preferable mode, however, the screw-post may first be 
 
58 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 fixed in the root, the crown adjusted over the post, amalgam 
 packed on the root and around the post, the crown seated firmly, 
 more amalgam packed in the crown cavity around the post, and 
 then a nut screwed on the post, as shown in Fig. 74. In all the 
 sectional cuts cement, amalgam, or gutta-percha is to be under- 
 stood as filling the cavities in the conjoined roots and crowns. 
 
 Fig. 72. 
 
 Fig. 74. 
 
 Fig. 75. 
 
 " Fig. 75 shows in contour a dovetailed crown mounted on a 
 superior molar root in the manner shown by Fig. 68. It is 
 obvious that the crown of Fig. 68 might be ground quite down 
 to the post ends, and yet be firmly held by the dovetail sides of 
 the central cavity." 
 
 Fig. 76. 
 
 in/^nr 
 
 THE GATES CROWN. 
 
 The Gates crown has become identified with the Bonwill, 
 owing to its similarity (Fig. 76). It is usually attached to the 
 root by a metallic screw (manufactured for the purpose), to which 
 amalgam will adhere, instead of the Bonwill pin ^ (Fig. 77). The 
 
 1 Dr. Gates originally used a double-ended oval-shaped screw. The How screws 
 (see page 52) manufactured by The S. S. White Dental Manufacturing Company 
 are applicable to these crowns. 
 
THE FOSTER AND ROWLAND CROWNS. 
 
 59 
 
 Fig. 
 
 screw is tirst inserted in the root and the amalgam packed around 
 it. In nearl}' all roots, at a reasonable distance up the canal, a 
 suitable place for fastening the end of the screw can be found. 
 Too much force must not be applied in its insertion, as a root is 
 easily split. In bicuspid and niolar crowns nuts are used on the 
 screws, which lit slots in the grinding-sui-face of the porcelain. 
 They are screwed into the amalgam or cement, and covered with 
 it in the process of cementation of the crown. 
 
 When it is desirable or necessary to construct a screw 
 for a special case, it should be made of iridio-platinum 
 wire (as this alloy, being hard, will well maintain the 
 edge of the thread). Gold is unsuitable, owing to the 
 action upon it of the mercury in the amalgam, even 
 though the amalgam is used " dry." 
 
 In forming a screw a coarse-thread screw-plate should be used. 
 The threads of most screws are cut too fine. 
 
 THE FOSTER CROWN. 
 
 The Foster erown (Fig. 78), which in general form is similar 
 to a crown introduced by Dr. H. Lawrence, of Philadelphia, in 
 1849, also resembles the Bonwill, but has less concavity at the 
 base. The crown is attached to the root by a headed screw or a 
 screw with a nut (Fig. 79), instead of the Bonwill pin. 
 
 Fig. 78. Fig. 79. 
 
 The How screws and instruments (Fig. 80) are best adapted 
 for use with these crowns. 
 
 THE HOWLAND CROWN. 
 
 This crown, which is similar in principle to one originally 
 introduced by Dr. C. TI. Mack, was devised by Dr. S. F. How- 
 land. It is attached like the TIow dovetail crown, with screws 
 that are first inserted in the root. It is used oidy on bicuspid and 
 molar roots, and consists of a hollow porcelain crown, with a 
 cavity in the crown sufficiently large to admit the screw or pins, 
 and, when necessary, a small })ortion of the root (Fig. 81). 
 
60 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 The method of setting this crown, as described by Dr. How- 
 land, is to shorten the root even with the gum with a stump file; 
 Fig. 80. fit the crown to the root; enlarge the root-canal so that a 
 I threaded pin of proper size will pass in easily, partially 
 
 fill the canal with zinc phosphate, and press the pin to 
 its place with pliers. The crown should then be filled 
 with zinc phosphate and pressed to its place, care 
 I being taken to hold it in position until the cement 
 " sets (Fig. 82). If any operator distrusts the ability of 
 zinc phosphate to make a perfect joint, a small quantity 
 of silver amalgam or gutta- 
 percha can be used to advan- 
 
 FiQ. 81. Fig. 82. 
 
 Fig 
 
 tage. 
 
 This crown is strong, and 
 
 during its test of several 
 
 years none have broken so 
 
 far as known. The mode of 
 
 fastening is strong, and has 
 the advantage of two pins when set on a bicuspid having two root- 
 canals. It is simple, and when set — no metal being in sight — it 
 is a perfect imitation of the natural tooth (Fig. 83). 
 
 THE LOGAN, BROWN, AND NEW RICHMOND CROWNS. 
 
 These crowns have their platinum posts or pins baked in the 
 body of the porcelain. In the Logan crown the base is made 
 Fig. 84. Fig. 85. Fig. 86. Fig. 87. 
 
 concave, to facilitate its adjustment to the end of the root, and 
 to give the cement a more reliable form. 
 
THE LOGAN CROWN. 
 
 61 
 
 The base of the Brown crown is convex, and that of the 
 new Eichmond Y-shaped, from mesial to distal side. The 
 preparation of a root for one of these crowns is, in general, 
 sihiilar to that for the Bonwill crown. The root-canal is en- 
 larged, and sliaped so that the post, if possible, at least at its 
 point, will fit tightly. Gutta-percha or oxyphosphate is used for 
 cementing in preference to amalgam. 
 
 Pig. 88 
 
 Fig. 89. 
 
 Fig. 90. Fig. 91. 
 
 The Lixidii Crnirii. — The Logan crown, now so extensively 
 used, is the invention of Dr. M. L. Logan. The method of 
 mounting is explained in all its details in the following article 
 by Dr. W. S. How : 
 
 " Fig. 84 shows a superior right central root, an end appear- 
 
 Fig. n2. Fig. 93. Fig. 94. Fig. 95. 
 
 ance of the same, and a Logan crown, front view. Fig. 85 ex- 
 hibits, at a right angle to the plane of the first figure, the same 
 root, its end, and the Logan crown, side view. In both figures 
 the root-canal is supposed to have been first drilled to a gauged 
 depth with an engine twist-drill. No. 154, and then enlarged by 
 means of a fissure-bur, No. 70, to the tapering form shown ; the 
 walls being subsequently grooved with an an oval bur, No. 90. 
 
62 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 The enlarged section, Fig. 86, shows the crown adjusted on the 
 root by means of cement or gutta-percha, which surrounds the 
 post and tills all the spaces in the root and crown. Fig. 87 
 shows the completed crown. Fig. 88 exhibits a bifurcated bictis- 
 
 FiG. 96. 
 
 Fig. 97. 
 
 Fig. 98. 
 
 Fig. 99. 
 
 Fig. 100. 
 
 picl root, its end appearance, and a Logan crown adjusted 
 to the root. Fig. 89 illustrates the best manner of bend- 
 ing the post. Fig. 90 shows a split post, and its adapta- 
 tion to a bifurcated bicuspid root is seen in Fig. 91. 
 Figs. 92 and 93 exhibit the mode of mounting the Logan crown 
 on a superior molar root, and Figs. 94 and 95 the same crown 
 in its relations to an inferior molar root. 
 
 " The preceding figures clearly present to the mind's eye of the 
 expert dentist the essential features of the Logan crown and the 
 method of mounting it. 
 
 " The details are as follows : In every instance where a root 
 is deemed ready to receive its filling, it should first be measured 
 through its canal from the cervical opening to the apical foramen, 
 and this may be accurately done with a gauge adjustable on a 
 delicate canal-explorer (Fig. 96). The same device serves to 
 measure the distance from the apex to which the canal should 
 then be filled (Fig. 97). It also gauges the depth to which the 
 drill may be carried. The proper degree of enlargement from the 
 bottom of the drilled hole will, of course, depend on the observed 
 size and character of the root. Every dentist should familiarize 
 himself with generic tooth-forms, so that when the length of an 
 incisor, cuspid, or other tooth-root is known, he can so nearly 
 determine its hidden outlines as to form with precision a corre- 
 
THE LOO AN CROWy. 
 
 63- 
 
 Fig. 102. 
 
 sponding enlargement of the root-eanal, such as is shown by the 
 several cuts. For preparing the roots, the Ottolengui root- 
 reamers (Fig. 101) and facers (Fig. 102) are very desirable instru- 
 ments. The reamers are made in three sizes to correspond with 
 the Logan pins. With a root-reamer of the appropriate size, 
 the root-canal is enlarged to tit the pin along its whole length, 
 and so hold the crown tirmly iixlependentb/ of the cement. With 
 a root-tacer a labial slope is given to the root-end, so that the 
 crown neck shall lit under the edge of the gum. Fig. 103 
 shows the method and its result, and the cross-section shows 
 how the cement encases the pin. The suitable preparation of 
 Fig. 101. the bifurcated roots of some 
 < A bicuspids and of all the mo- 
 lars is a matter involving 
 difficulties of an unusual 
 character and requiring good 
 iudo-ment. The feasibilitv of 
 splitting the post of a Logan 
 crown to adapt it to the 
 bifurcated root of a bicus- 
 pid is shown hy Figs. 90 ami 
 This example directs attention to 
 the peculiar shape of the post, in which 
 there is effected such a distribution ut 
 the metal that its greatest strength is 
 in the line of the greatest stress that 
 will in use be brought to bear on the crown, while the least 
 metal is found at the point of the least strain ; the apphed part 
 of the post being in outline nearly correspondent to that of the 
 root itself. The root-canal is likewise conformably enlarged to 
 receive the largest and stiffest post which the size and shape of 
 the root will permit. 
 
 " The fitting of a Logan crown to a root may be done with a 
 wet stump-wheel in the engine hand-piece. Using a safe-side 
 crown corundum-wheel (Fig. 104), in the same manner, affords 
 the greatest facility for the slight touches required to abrade the 
 thin cervical borders of the crown, which may by this means be 
 done without encroachment on the post. 
 
 91 
 
 D 
 
 
 
64 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 " By the old method of adapting pivot-teeth to roots, the 
 close fitting of the crown precluded the use of a plastic packing, 
 because its thinness over the surface of the joint made the pack- 
 ing liable to break loose under the shock and strain of use. 
 The recess in the Logan crown obviates this defect by providing 
 a receptacle for a considerable interior body of cement that will 
 be deep enough to be self-sustaining internally, and yet allow 
 the peripheral portions of the root and crown to approach each 
 other so closely that, though only a film of packing remain, it 
 will still be strong enough to insure the persistent tightness of 
 
 Fig. 103 
 
 the joint. This annular boss if formed of amalgam also adds 
 strength in some cases to the mount. 
 
 " When enough of the natural crown remains, it is well to 
 leave standing some of the palatal portion, and cut the root 
 under the gum margin at only the labial part, as shown by 
 Fig. 98. The safe-side crown Avheel is especially useful in such 
 cases (Fig. 105). Thus the lal)ial joining of the root and crown 
 will be concealed, and the other parts of the joint will be acces- 
 sible for finishing and keeping clean (Fig. 99). The Logan 
 crown may be ground until a large part shall have been removed 
 for ada|)tation to the occluding tooth or teeth without seriously 
 impairing its strength (Fig. 100). This crown also in such 
 
THE BRO WN CRO WN. 
 
 65 
 
 cases maintains the translneency which is one of its peculiar ex- 
 cellences, owing to its solid porcelain body, and the absence of 
 a metallic backing or an interior largely lilkMl witli cement or 
 amalgam. 
 
 "• The distal buccal root of the natural superior molar is nearly 
 always too small to receive a post of any useful diameter, and 
 therefore the Logan superior molar crown has Init two posts, 
 which like those of the inferior molar crown are square, and 
 thus may ])e easily l)arbed, as may also the riblied posts of the 
 crowns for the anterior tooth-roots. These posts are large enough 
 in all the Logan crowns to answer in any given case, and can of 
 course l)e easily reduced to suit thin or short roots. 
 
 "Any of the cements or amalgams may be used in fixing these 
 crowns, but good gutta-percha, softened at a low heat and (piickly 
 
 Fig. 104. 
 
 Fig. 105. 
 
 wraj)j)ed around the heated crown-post, which is at once seated 
 in the root, forms the best mounting medium, and has the great 
 ad\"antagc of permitting a readjustment, or, if need be, the ready 
 removal of the crown by grasping it with a \n\\v of liot jihers or 
 forceps, and holding it until the gutta-i)ercha is sutiieiently 
 softened." 
 
 The Broir), Croirn. — Fig. 106 is a lateral view of a porcelain 
 crown, with an iridio-platinum pin baked in position, invented l)y 
 Dr. E. Parnily Brown. The pin has great strength at the neck 
 of the tooth, where the strain is heaviest, and this strength is fur- 
 ther increased by extending the porcelain up on to the pin. 
 
 Fig. 107 is a front view of the same crown, showing by the 
 
 5 
 
66 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 clotted lines the shape of the phi and the position which it occu- 
 pies in the crown. 
 
 The pin is flattened laterally, a conformation which affords a 
 strong hold in th<^ porcelain without permitting the pin to ap- 
 proach the surface in thin teeth, while it also permits alteration 
 of the palatal surface of the crown in a close " bite " without 
 risk of weakening the body. 
 
 Fig, 108 is a view of the bicuspid crown, in which a pin is pro- 
 vided for each root of two-rooted bicuspids. 
 
 Fig. 109 is a view of a bicuspid crown with the two pins 
 pressed together, forming a single pin of great strength for a 
 tooth with only one root. 
 
 The double pin in the bicuspids prevents the gradual loosen- 
 ing of the crown by the rotary movement of the jaws in mastica- 
 tion, which, acting on the two cusps, exerts such leverage as to 
 
 Fig. 106. 
 
 Fig. 107. 
 
 Fig. 1 
 
 Fig. 109. 
 
 sometimes turn and break down ordinary crowns where only one 
 pin is used. 
 
 The roots are ground concave to lit the crowns with corundum- 
 points or a Willard countersink bur, and close joints are made 
 well under the gum, the pins being set with oxyphosphate 
 cement. The canal should be enlarged enough only to admit 
 the pin, which should fit snugly throughout its entire length, the 
 better to distribute the leverage exerted by the crown, and thus 
 directly to increase the strength of the attachment. (For process 
 of cementation, see article on "Insertion and Cementation.") 
 
 The Neiu Richrnond Crovm. — To illustrate and describe the 
 method of mounting this crown, a superior left central incisor 
 root will serve as a ty]»ical case, and its projecting end is to be 
 shaped as seen in Figs. 110 and 111. This can be rapidly done 
 with a narrow safe-sided flat or square file, the angles of the 
 
THE NEW RICHMOND CROWN. 
 
 67 
 
 slopes ])ciiig such that the gum on the hiMal and pahital as[ieets 
 will not interfere with nor l)e disturhed hv this preliuiinarv work, 
 as the root end is not, in this operation, to he cut quite down to 
 the gum. An Ottolengui root-reamer jS^o. 2 is then employed to 
 bore out the root to receive the crown-pOvSt, which is of the same 
 size and shape as the Logan crown-post for a central incisor. 
 
 The sectional view (Fig. 112) sliows the relation of the reamer 
 to the root. The new Richmond crown (Fig. 113) is then tried 
 on the root (Fig. 114), and its position relative to the adjacent 
 and occluding teeth noted. If the cutting-edge of the crown is 
 to be brought out for alignment with its neighbors, the root can 
 be drilled a little deeper, and the reamer pressed outward as it 
 revolves to cut the lal)ial wall of the ca\'ity. Tlie palatal yooX- 
 slope must then V)e filed to make the V correspond to the changed 
 inclination of the crown. 
 
 Fig. 110. 
 
 Fig. 111. 
 
 Fig. 112. 
 
 Thus, by alternate trial and reaming and tiling, the crown 
 may be fitted to the root and adjusted in its relations until the 
 post has a close, solid l^earing against the labial and palatal walls 
 of the enlarged pul})-chamber, and the crown-slo[)es are se})arated 
 from the root-sloi)es by the thickness of a sheet of heavy writing- 
 paper. This space can be accurately gauged, and the root-slopes 
 conformed to the crown-slopes by warming the crown and put- 
 ting on its slopes a little gutta-percha, so that an impression of 
 the root-end may be taken, and the root-slopes dressed with a 
 file until the film of gutta-percha proves to be of equal thinness 
 on l)oth slo[>es. 
 
 To permanently attach the crown. Dr. liichmond usually takes 
 a thill, perforated disk of gutta-]ici-cha, ]iushes the post through 
 
68 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 it, warms the crown, presses it into place, and when cooled 
 removes it, and with a sharp knife trims away the gutta- 
 percha close to the crown-neck. He then warms the crown, 
 puts a very little oxyphosphate cemient on the post, and presses 
 the crown home. Fig. 115 shows the completed crown. 
 
 The obvious advantages of the device are the readiness ^^dth 
 which the slopes of the root-end may he shaped with a file ; the 
 facility with which these slopes may be given any angle to set 
 
 Fig. 113. 
 
 Fig. 114. 
 
 Fig. 115. 
 
 Fig. 116. 
 
 the crown out or in at the base or at the cutting-edge, or to give 
 it a t^vist on its axis; the certainty that, once adjusted, the final 
 setting will exactly reproduce the adjustment; the assurance 
 that in use the crown "\^'ill not be turned on its axis, — a most 
 common cause of the loosening of artificial crowns ; the firm- 
 ness of its resistance to outward thrust in the act of biting. 
 This is made apparent l)y Fig. 116, wherein it will l)e seen 
 that in an outward movement the crown B would rock upon A 
 
 Fig. li: 
 
 Fig. 118. 
 
 Fig. 119. 
 
 as a }iiv()t. The dotted line D shows liow the crown-slope is 
 resisted by the root-slope, ^^•hicll extends so far towards the 
 incisive edge that a much firmer support is given to the crown 
 than if the resistance should be, as it usually is, on the line of 
 the ffintj-ival niaru'in C. 
 
REMARKS ON THE USE OF PORCELAIN CROWNS. 69 
 
 For roots that have liecoiue wasted Ix-low the gum-surface it 
 is iu)t suital)le, except in such cases as are decayed under the 
 hd)ial or })alatal o'uni-margin only, hut have yet projecting the 
 a}>pr()xirual portions of the crown (Fig. 117). 
 
 The sectional view (Fig. 118) and the perspective plan views 
 (Fig. 119) illustrate the manner of mounting these crowns on 
 this class of roots. Tlie finished crown appears as in Fig. 119. 
 
 The cases for which this crown seems specially adapted are 
 such as have some considerable portion of the natural crown 
 remaining. 
 
 REMARKS ON THE USE OF PORCELAIN CROWNS. 
 
 P(n'celain crowns have some decided advantages. They are 
 especially useful in many cases where an inexpensive or easily 
 adjusted crown is recpiired; or where some pathological C(in- 
 dition limits the probable duralnlity, or permanency, of any 
 operation. In the insertion of porcelain crowns, the removal of 
 the whole or a part of the natural crown, which could l)e uti- 
 lized to some extent as a foundation 1)y other systems, has given 
 rise to various oljjections. If tlie natural erown is entirely cut 
 away, the pin, or post, u[>on which almost the entire su}»port (^f 
 the artificial crown is thrown, acts like a lever in the root-canal, 
 there being no band or brace to relieve the strain. With the 
 whole force of mastication bearing directly upon these puljdess 
 roots, whose disintegration is slowly but constantly progressing, 
 the inevitable result can well be conjectured. Sooner or later 
 they are fractured, and their usefulness as a foundation ended. 
 Then, again, if porcelain crowns are attached Avith amalgam, 
 the discoloration of the line of union with the root, if subse- 
 quently exposed, is disfiguring. These facts, and the lark of 
 strength incident to some forms of construction, are the priiu-i- 
 [)al objections urged against porcelain crowns as ordinarily 
 inserted. 
 
CHAPTER IL 
 
 PORCELAIN CROWN WITH GOLD COLLAR ATTACHMENT. 
 
 A GOLD collar, either seamles-^ or soldered, can be used advan- 
 tageously in combination witli many of the porcelain crowns. 
 
 The root having been properly prepared, a collar is adjusted 
 and adapted to it the same as for a gold collar crown (see page 
 '79). The porcelain crown, the base of which should l)e fully 
 as large as the end of the root, is then ground even \^'ith the 
 cervical walls, and fitted into the collar, which should be trimmed 
 and Ijurnished to the form of the crown. Enough of the collar 
 should be trimmed away at the labial portion to Y)revent too 
 conspicuous exposure of the gold (Fig. 120). 
 
 Fig. 124. Fig. 125. 
 
 Pig. 120. 
 
 Fig. 121. 
 
 Fig. 122. 
 
 Fig. 123. 
 
 This collar combination is available in very difficult cases, as, 
 for instance, when a root is decayed far beneath the gum, as 
 seen in Fig. 121. 
 
 Such an operation, when completed, would appear in vertical 
 section like Fig. 122, and a view in perspective would resemble 
 Fig. 123. The collar is also very useful wherever the root and 
 crown are not made flush and smooth at every point, as, if prac- 
 ticaT)le, they should always l)e. 
 
 Dr. E. C. Kirk, of Philadelphia, uses for Incuspids and molars 
 a Foster crown in combination with a collar (Fig. 124). A collar 
 70 
 
PORCELAIN CROWN WITH GOLD COLLAR ATTACHMENT. 71 
 
 is made, and, on l)eing fitted to the root, is cut narrow on the 
 labial side, and left wide on the linarual, so that it shall extend 
 nearly to the cusp of the crown when finished (Fig. 125). (The 
 seamless gold collars are well suited for application to this style 
 of crown.) 
 
 The crown selected should liave a somewhat greater circum- 
 ference at the base than the collar, so that Avhen ground down 
 somewhat conically on its lingual and approximal surfaces, it 
 can V)e tightly adjusted to the collar. If a crown smaller tlian 
 the collar is used, a tight joint cannot he made. The screw is 
 fitted so that it shall hold the crown in proper relations with the 
 root. The screw and crown are then removed, the parts dried, 
 and the root-canal filled with a slow-setting ox}^3hosphate cement, 
 mixed thin. The crown is then pressed into its position, the 
 surplus cement flowing through the opening in the porcelain 
 and filling up any interstices around or between the band, the 
 root, and the crown. The screw is then driven into position, 
 and when the cement is set perfectly hard the head of the 
 screw or the nut on it is notched to form a retaining-pit, and 
 the countersink of the crown filled with gold. 
 
 Dr. C. S. W. Baldwin, of IS'ew York City, caps the root and 
 attaclies a Logan crown in the following manner. 
 
 First, the root is shaped, the (juter margin being beVL-led 
 al)Out tile thickness of the gold used, to aftbrd regular sides foi" 
 close ada})tation of the caps. Then an impression is taken and 
 a die made in the gold seamless cap method. To strike up the 
 cap, place Xo. 32 gauge gold plate on a cushion of lead, holding 
 the die firndy on the gold where you wish to produce the cap, 
 and strike until the recpiired depth is secured before remo\'ing it. 
 This drives the gold and die into the lead, forming a female die 
 and a perfect-fitting cap at once, in less time than is occupied in 
 describing the process. Trim the edges to fit the festoon of 
 the gum. and drill a hole from the inner side \'ov the pin, leav- 
 ing the raggedness made l)y drilling to catch in the cement. 
 Place the ca}) on the root and fit the }iorcelain crown accurately 
 to it in the desired occlusion and position. A Logan erown 
 can, with little grinding, be made to do good service (Fig. 126). 
 A crown having the H-sha[ied pin, but scpiare on the edge, Hke 
 
72 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 some of the early patterns of Logan or Bonwill crowns, would 
 reduce the thne of setting and give best results. Having 
 polished the edges of the cap, the crown may he conveniently 
 adjusted as follows : Place ox^^i^hosphate cement in the counter- 
 sunk portion of the porcelain, and in the canal only enough 
 cement, of creamy consistence, to fill it, as the pressure required 
 to force out the surplus under the edges of the cap destroys 
 many nicely adjusted crowns, leaving bulging irritants instead 
 of smooth supports. If proper attention has been given to 
 fitting crown and root, all will come nicely to place, but in some 
 cases of difficult adjustment it may be necessary to cement the 
 crown to the cap before fastening the pin in the root (Fig. 127). 
 Fig. 126. Fig. 127. Fig. 128. Fig 129. 
 
 In most cases the gold l)and will be invisible and below the 
 free margin of the gum. Cases may occur where the anterior 
 teeth are prominent, and it will be necessary to cut away the 
 top of the cap in front, allowing the porcelain to come directly 
 in contact with the root, the band going deeper than in ordi- 
 nary cases, which prevents the appearance of gold (Fig. 128). 
 
 Dr. Bonwill's \A-An is to cap the tooth with a platinum or gold 
 cap having a slot, into which the pin passes as it is slipped on 
 the root (Fig. 129). Tlie crown is then tastened on with amal- 
 gam in tlie usual manner. 
 
CHAPTER III. 
 
 THE WESTON CROWN. 
 
 Dr. Henry Weston's method of crowning is (leseril)ed by him 
 as tollows : 
 
 " This crown represents on its hiljial surface the ordinary phite 
 tootli, tile hngual or })ahital surface being concaved in such 
 a manner as to afford the hirgest amount of working room Avith- 
 out impairing its strength at any point. The pins are so 
 imbedded in the thickest part of the crown that it is not hal)le 
 to be weakened by grinding. Fig. 130 represents the crown. 
 
 Fig. 130. 
 
 Fig. 132. 
 
 Fig. 133. 
 
 Fig. 134. 
 
 Fig. 135. 
 
 " Tlie pin is made of hard platinum and iridium, and is spear- 
 shaped and notclicd on both edges to give tirmness to its 
 anchorage. The b;n'king is of tlie same metal and strongly 
 soldered to the [)in. Fig. 131 represents the pin. 
 
 '" Tbe preparation of the root for tlie reception of the crown 
 consists in the removal of that part of the tooth which is to 
 be replaced by the porcelain. Fig. 132 shows the root at this 
 stage. 
 
 " The canal must be sufficiently enlarged to allow space for 
 packing gold or amalgam securely about the pin, and the sides 
 reamed (Fig. 133). 
 
 ''The grinding of the i-ro\vn to tbe root re(piires but little 
 labor, and tbe tittinu' mav be done directh" on tbe natural I'oot, 
 
74 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 or on a cast taken after the root has heen prepared. This must 
 always 1;)e done T^^th the ntmost neatness and precision. When 
 fitting, the crown can be hekl in position by a cone of wax in- 
 serted in the root. Next comes the adjustment of the pin to the 
 root of the crown. After punching holes in the backlog to 
 receive the pins of the porcelain crown, bend the pin with small 
 flat-nosed pliers, so that when in its proper position there shall 
 be a uniform space around its entire surface. 
 
 " Secure the tooth and pin together with a cement of resin 
 and wax, invest in plaster and sand, and solder with fine gold 
 solder. 
 
 " It has been my practice of late years when preparing the 
 root to leave just a line of enamel around its entire circumfer- 
 ence, thus securing a joint clear of the free edge of the gum, 
 especially when gold is used. If gold is to be used as the 
 attachment, the rubber-dam is indispensable. When amalgam 
 or cement is used, the rubber-dam may be dispensed with 
 b}' those who prefer other methods of keeping out moisture. 
 When gold is to be used, the root having been pre\dously 
 properly treated, and everything in readiness and the rubber- 
 dam in place, put upon the point of the pin a pellet of phos- 
 phate or oxychloride of zinc, the size of a No. 7 or ISTo. 8 exca- 
 vating bur ; now press the pin and crown carefully to their exact 
 position into and upon the root, and with a delicate but 1)lunt- 
 pointed instrument, thin enough to reach the end of the canal, 
 pack the cement firmly aljout the pin. The ol^ject in using the 
 cement is to secure the pin in its place during the first introduc- 
 tion of the gold. By using the hot-air syringe, the cement will 
 harden in two minutes. Close the opening of the canal al)out 
 the pin with a rope of bibulous paper, and attach the crown to 
 the root and adjoining teeth on either side with soft wax; see 
 that the joints are exact in every particular, as after the next 
 step mistakes are not easily remedied. 
 
 " Paint the joint from the labial side with cement mixed to 
 the consistence of cream. Cover the labial surfaces extending 
 over the cutting-edges of the porcelain crown and adjoining 
 teeth to the thickness of three-eighths of an inch with carefully 
 mixed impression plaster. When hardened, the plaster may be 
 
THE WESTOX CROWS. 75 
 
 cut from the cuttiiig-edge of the crown, and the wax and the 
 paper removed. Xow paint the pahital sides of the joint with 
 the cement mixed to a cream-like consistency, applied with flat- 
 tened root-canal plnggers. Harden with hot air, and the case 
 is ready for the gold. 
 
 " When filled and finished, the exposed dentine and enamel 
 are all covered with eohesive gold and i)oreelain; the result will 
 J)e a tac-simile of Figs. 134 and 135. 
 
 " If preferred, the cement in the labial joint may l»e dispensed 
 with, and the space between the crown and the root carefully 
 filled with gold after the removal of the plaster, covering all of 
 the ex^josed root and showing only a fine line of gold at the 
 margin of the gum. 
 
 " Where amalgam is used exclusively for tlie attachment, the 
 greatest accuracy should be oljserved in the proper articulation 
 of the crown before introducing or packing it and in remo^'ing 
 carefully all excess, and the patient should lie cautioned against 
 bitintr on the crown until the followino- dav." 
 
CHAPTER IV. 
 
 PORCELAIN CROWNS WITH RUBBER OR VULCANITE ATTACH- 
 
 MENT. 
 
 Fig. 136. 
 
 Fig. 136 illustrates the formation of such a crown. The root, 
 when prepared, extends at the palatal side a little below the line 
 of the gum (A) at the point B. A plate-tooth 
 (C) is ground and fitted to the root. An iridio- 
 platinum post is then fitted to the root, flattened 
 slightly and Vjent at D, and riveted to the tooth. 
 The proper alignments of the tooth and post to 
 the root are then obtained, and they are invested 
 and the jtost soldered and strengthened at the 
 point D. The backing is then grooved and 
 / notched slightly, wax applied, the crown ad- 
 justed to the root, and the wax shaped so as to 
 form a foundation and overlapping edge at the 
 }»alatal portion (E). The crown is then re- 
 moved, invested in a flask, packed with rubber, 
 and vulcanized. In trimming and finishing, 
 the ruljber is allowed to form a partial band 
 or collar around the palatal portion of the wax, 
 where it will not show. It is then cemented on to the root Avith 
 oxyphos})hate. 
 
 The Weston crown and the four-pin How crowns have ad- 
 vantages over ordinary plate-teetli in the construction of this 
 style of work. 
 
 76 
 
THE GOLD SYSTEM. 
 
 CHAPTER V. 
 
 PORCELAIN AND GOLD CROWN WITHOUT A COLLAR. 
 
 The root of a cuspid will be taken as a typical case to illustrate 
 the construction of this style of crown. 
 
 The end of the root is prepared the same as for a porce- 
 lain crown (Fig. 137). The root-canal is then uniforndy en- 
 larged a reasonable distance up, with a drill Avliicli will tightly 
 fit the opening. Into the canal, gauging its full diameter, is 
 
 Fig. 137. 
 
 Fig. 139. 
 
 Fig. 140. 
 
 Fig. 141. 
 
 fitted a piece of iridio-phitiiitini ^\'ire, tapered off to a point, so 
 that by introducing it far up the canal greater strength can l)e 
 obtained, and the root rendered less liable to longitudinal fracture 
 from pressure in a f)rward direction. A ]iiece of }tlatiiuim 
 plate, a trifle larger than the end of tlie root, of about Xo. 30 
 U. S. standard gauge, with a hole ])unt'hed in its center, is then 
 slipped on the post, which it nuist fit tiglitly (Fig. 138). 
 
 When the post is adjusted firndy in the canal, the ]tlatimim 
 plate is pressed down on the root, and burnished into the orifice 
 
78 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 of the canal around the post. "When the post is withdrawn from 
 the root, the phitinum will adhere to it, if fitted closely, with- 
 out the use of wax. A particle of pure gold with borax is 
 put in the joint, and melted in the flame of an alcohol lamp. 
 Barely enough gold should be used to unite the parts. "When 
 soldered, the post and cap are again adjusted in the mouth and 
 the cap malleted and burnished to the form of the end of the 
 root, so that its edge will leave a mark on the platinum. The 
 cap, on being removed, should be trimmed to this mark, and 
 again burnished on the root (Fig. 139). Sometimes around the 
 palatal portion of the root the }:)latinum may be slightly bur- 
 nished over the edge. The post is then cut off just above the 
 platinum, and a plate tooth fitted, backed, and cemented with 
 wax in position on the cap. The whole is then removed, 
 invested, and soldered with gold at least twenty carats fine, which 
 should be melted in at the l)ase of the post, as at this point, 
 when in use, the strain is very great. The post is then barbed, 
 and the crown is cemented to the root with gutta-percha or oxy- 
 phosphate cement (Fig. 140). 
 
 Dr. F. T. Van Woert, of Brooklyn, i^. Y., in constructing 
 crowns of this style, shapes the end of the root, and adapts the 
 cap as shown in Fig. 141. The slant given to the palatal side 
 aids the root to resist force in a forward direction. 
 
CHAPTER A'l. 
 
 GOLD COLLAR CROWNS. 
 
 This stvle of o-old crown iiicludes tlio.se iiiethodt^ wliieli consist 
 in l)anding, capping, and liernietieally inclosing with gold the 
 end or the neck of a root, with or without any jiortion of a 
 natural crown, for the })urpose of securing stahilitv to the arti- 
 ficial crown, preventing fracture of the root and decay of the 
 parts, thus permanently preserving them. This method pos- 
 sesses much practical vakie as a preserver of tooth-structure and 
 restorer of usefulness to the teeth, and affords excellent supports 
 for hridge-work. 
 
 The use of the collar crowns was first described l)y Dr. Wm. 
 H, D\\dnelle in the application of the method to a crown with a 
 porcelain front,^ and by Drs. W. N. Morrison^ and J. B. Beers ^ 
 in the construction of all-gold cap crowns. 
 
 Collar crowns of which the part that essentially constitutes 
 the cap is constructed in sections, will be first described. 
 
 THE CONSTRUCTION AND ADAPTATION OF COLLARS. 
 
 Careful study of the ditterent forms of crowns and roots, and 
 of the anatomical structure and relationship of the contiguous 
 parts, is most essential for the perfect construction and adapta- 
 tion of collars, ]>ands, or ferrules, as they are variously designated. 
 
 Many devices and methods in use facilitate this operation, 
 but its skillful performance can oidy be attained by study and 
 practice, as is proved by the easy and perfect manner in which 
 it is done by experts in crown- and bridge-work, who use no 
 a[)pliances but pliers and shears guided by an intuitiw ]»ercei)- 
 tion of the requirements of each case. 
 
 ^American Journal of Denial Science, April, 1855. 
 - Missouri Dental Journal, May, 1869. 
 ■^Circular to dental profession, 1873. 
 
 79 
 
80 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 142. 
 
 Fig 143. 
 
 The collar is preferably made of coin gold, or of 22 to 23-carat 
 gold plate. Pure gold plate lined with platinum is also used, 
 and iridio-platinum plate in special cases. 
 
 Gold plate of No. 32 to No. 34, or gold and platinum or 
 iridio-platinum of No. 34 or No. 35, U. S. standard gauge, 
 aflbrd the requisite strength, together with easy adaptation to 
 the form of the crown or root. The natural crown or root 
 ha\dng previously been properly pre})ared (see page 37), a strip 
 of the metal is cut of the length required, and generally from 
 one-fourth to one-half of an inch in width (Fig. 142). The end 
 to form the underlap is beyeled with a file. The strip is then 
 bent with suital)le pliers (Fig. 143) to the average form (Fig. 144) 
 and the size of the cervical periphery of 
 the root of the tooth to be crowned, any 
 special deviation from such average being 
 noted (Fig. 145). It is then placed on the 
 root and adapted as closely as possible to 
 its form, with the upper edge of the metal 
 pressing gently under the free edge of any 
 portion of the gum it may meet. It is then 
 removed and cut so as to allow the ends 
 to lap over slightly. The adaptation to 
 the root is then continued, during which 
 process the metal should be heated and 
 chilled in water after each trial, in order 
 to maintain the shape given to it. At the 
 last adjustment to the root, the lap-over is 
 marked on the metal with a sharp-pointed 
 instrument. The joint is made at this 
 mark l)y placing there the least possible 
 quantity of solder and holding the collar in the flame of an alco- 
 hol lamp or a blue gas flame. The collar is then slipped on the 
 point of a small anvil, and the joint tapped down and trimmed 
 level. 
 
 When a mandrel is used in forming a collar, the size or shape 
 of the root is first taken l^y encircling it with a piece of fine 
 iron or copper wire, about No. 28 U. S. standard gauge, and 
 twisting the ends together on the labial side. The Avire is then 
 
THE CONSTRUCTION AND ADAPTATION OF COLLARS. 81 
 
 pressed up on tlu' root about as far as the upper edge of the 
 
 collar is to go, and l)uniishc'd to the sides (Figs. 146 and 147). 
 
 The wire ring is then earefnlly removed, laid on a piece of air- 
 
 chand)er tin, a piece of flat iron put over it, and with a blow 
 
 from a hammer on the Fig. 144. 
 
 iron the wire is driven 
 
 into the tin (Fig. 148). 
 
 The wire ring is removed 
 
 from the tin, slipped on 
 
 a mandrel ^ that represents 
 
 the form of the root to l)e 
 
 crowned and pressed down 
 
 gently as far as it will go 
 
 without stretching the wire 
 
 (A, Fig. 149). The gold 
 
 to form the collar is then ^-.^^^ 
 
 bent and shaped on the \ ^^ 
 
 mandrel. The edge which 
 
 is to form the cervical 
 
 portion (B) is placed a 
 
 little below the line of the 
 
 wire (A). The ends of the 
 
 gold are l)eveled, slightly 
 
 lapped, and the edge of 
 
 the lap-over marked C. 
 
 The collar is then removed 
 
 from the mandrel and, the 
 
 ends being held together 
 
 with common tweezers, 
 
 which are grasped l)y 
 
 y ^ 1+4- f'11 1 " '^'"^ palatal sido of the superior molars, in many 
 
 pners, or Detter still, by cases, is of the largo oval form indicated by the outer 
 
 a small hand-\"ise (Fig. I'^e to the formofthe first molar. The small spurs in- 
 
 ^ ^, , \ &• dicate the points generally found the most suitable to 
 
 15U), tllC extreme outer make the joint. 
 
 end of the Joint is united l)y an atom of solder with a blow- 
 pipe. The j)oints of the tweezers prevent the solder from 
 flowing along the joint, leaving the cervical portion still open. 
 
 ^A description of mandrels will be found in the chapter on the "Mandrel 
 
 System." 
 
 6 
 
82 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 The folla]' is then shaped to the form given h_v the wire in 
 the tin, which haA'ing l)een done it is ready for adjustment 
 in the mouth. The open side permits the collar to be easily 
 
 Fig. 145. 
 
 Tig. 146. 
 
 Fig. 147. 
 
 Fig. 148. 
 
 and accurately adapted to the root, after which the solder can 
 be flowed across the joint. 
 
 When the collar has been ff)rmed, it is adjusted on the root 
 and pressed up to the margin of the gum. A line parallel with 
 the margin is marked with a sharp-pointed instrument on the 
 gold (A, Figs. 151 and 152). The collar is then removed, 
 
 Fig. 149. 
 
 Fig. 150. 
 
 cro 
 
 Fig- 151. 
 
 Fig. 152. 
 
 trimmed to this mark, readjusted, ami again marked (B), and 
 the process continued until the collar fits proportionately under 
 the mar.u'in of the gum. The edge of the collar is then l)nr- 
 
vmrn €m3^wm.i!j€mm^3f Asm ai»aptat]qs of oozz-U^. x3 
 
 
 Fi6. 15B. 
 
 '^ 
 
 
 -=^ ^^ 
 
 :tif ttSM" Tirntair gTrBi <<Titf' iihui- gn ijaaii fciD'fij 
 
CHAPTER VIL 
 
 GOLD COLLAR CROWNS WITH PORCELAIN FRONTS. 
 INCISORS AND CUSPIDS. 
 
 This style of crown for incisors and cuspids, as originally 
 made by Dr. C. M. Richmond, and with which his name has 
 become associated, consisted of a cap for the root, formed of a 
 band of gold capped with platinum on which was soldered a 
 tooth with a slot in the center between the pins. Through this 
 slot a screw passed which entered into a cylinder previously 
 screwed and cemented into the root-canal. 
 
 The form of gold collar crown in general use at present is, in 
 principle, the same as what has been known in dentistry as a 
 gold pivot tooth, with the addition of a gold collar for the root, 
 and having the advantage of oxyphosphate for its cementation. 
 These improvements, however, enhance its value as a crown, 
 and materially change the process of its construction. In 
 miaking an incisor or cuspid crown of this style, the collar, 
 having l)een formed, is trimmed even with the surface of the 
 end of the root. With the collar in position on the root, a 
 corundum-wheel is passed over the labial edge, along the margin 
 of the gum, to level the gold with the root and render it invisible 
 when the crown is finished. The work will then ]:)resent the 
 appearance shown in Fig. 154. 
 
 The cap is made by adapting the surface of a very thin piece 
 of platinum plate to the Jower edge of the collar, and uniting 
 them with solder in the flame of a lamp (Fig. 155). The quan- 
 tity of solder used must be very small, and it should be placed 
 on the platinum outside of the collar, as otherwise it will flow 
 over the inside of the collar and interfere with the tit of the cap. 
 The platinum is then trimmed to the collar, and the cap adjusted 
 on the root. The labial section of the surface of the cap is 
 84 
 
GOLD COLLAR CROWNS WITH PORCELAIN FRONTS. 
 
 85 
 
 tlic'ii bnrnisliod to the end of the root (A, Fig. 154). Tlie I'oot- 
 canal liaving l:)een sliglitlj enlarged, a pin of round iridio- 
 platinum wdre, ISTo. 16 or 17, U. S. standard gaitge, — tiled a 
 little smaller for laterals or other roots wliieli require it, — is 
 slightly tapered at the point, titted to an aperture made in the 
 cap, and to the canal (B). The pin is then cut off even with the 
 cap, removed, and tem])orarily laid aside. 
 
 A liollow Avire, tlic o]ien space in the center of which is very 
 small, has lately been intro(hiced for use in crown-work by 
 Dr. J. G. Morey. The advantage it confers is the comparatively 
 easv manner in which it can l)e drilled out of tlie canal if for 
 
 Fig. 154. 
 
 Fig. 155. 
 
 Fig. 156. 
 
 any reason it becomes necessary to remove the crown, as the 
 drill will follow the tine opening in the center of the wire. 
 
 A plain-plate cross-pin tooth, suitable in form and color, is 
 groinid and fitted in position on the ca]). The lal)io-cervical 
 edge of the jiorcelain (A, Fig. 156) should l)e flush with the vilga 
 of the collar, and meet the margin of the gum. It should be 
 cut out at the base (B) so as to form a slight s]>ace Just ovei- the 
 end of the ])in. The tooth is then l)acke(l witli very thin ])ure 
 gold, gold lined A\ith platinum, or pure ])latinnm. Platinum 
 gives a faint l»lue sluule, and gold, or gold lined with ])latinum, 
 if the gold side is toward the porcelain, a slight yellow shade. 
 The backing should extend as far as ])<)ssible under and between 
 the tooth and the cap, as the solder will flow in aiul fill the space, 
 thus giving strength and continuity of structure. The backing, 
 if bent over the incisive edge (C) at a right angle, will ]>rotect 
 the porcelain in occlusion. A nai-row strip of fine gold ]»laced 
 transversely across at that point ]ire\iousto investing, and united 
 in the soldering of the backing, will answer the same purpose. 
 
86 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 The tooth, Avhen backed, is secured hi position on the cap 
 with a compound of wax and resin, and the whole adjusted in 
 the mouth, then removed, and the pin, which has been laid 
 aside, warmed and placed in position by passing the end from 
 the inside of the cap through the hole into the wax attaching 
 the porcelain crown. Another adjustment in the mouth is then 
 made to determine the exact line for the pin, and the case is 
 ready for investment. 
 
 After the fitting of the pin to the root and root-canal, as has 
 been described when the cap was formed, some prefer to solder 
 it to the cap, for which purj^ose it should be adjusted in position 
 and cemented with wax, then removed, invested, and soldered 
 (Fig. 157). At this stage of the work, if desired, an impression 
 can be taken in a small impression cup (Fig. 158) with either 
 plaster or modeling compound. The cap should l)e removed in 
 
 Fig. 158. 
 
 Fig. 159. 
 
 Fig. 160. 
 
 position in the impression. To aid this, a piece of gutta-percha 
 can be put on the end of the pin projecting from the cap. An 
 articulation of the lower teeth should also be obtained. When 
 the model is made, the pin is cut off even with the cap, and the 
 porcelain tooth fitted as already described. 
 
 Calcined marble-dust and plaster, in the proportion of two 
 parts of marble-dust to one of plaster, to which is added a pinch 
 of sulphate of potassium to quicken the setting, makes Avhat is 
 considered to be the most suitable investing material for crown- 
 work. The crown, when invested, should be left exposed at the 
 sides, as illustrated in Fig. 159. The flame should be pointed 
 in the direction A, and the investment heated uniformly, so 
 that the solder is flowed between the jDorcelain crown and the 
 cap. Only sufiicient gold should be used to insure restoration 
 
GOLD COLLAR CROWNS WITH PORCELAIN FRONTS. 
 
 87 
 
 of contour. When soldered, after having l)een placed in acid 
 and thoroughly divested of l)()ra\', the crown is ready for the 
 finishing and polishing })rocess. Fig. 160 re[»rescnts the com- 
 pleted crown. 
 
 BICUSPIDS AND MOLARS. 
 
 Bicuspids crowned bv this method will have greater strength 
 if a })ortion of the ])alatal section of tlie natural crown is reserved 
 (Fig. 21), and the hand or collar made deep enough to cover it. 
 
 The end of the root is capped after the manner of the fv})ica] 
 central already described, one or two ]tins being used in the 
 canals as re([nired. A porcelain cusjiid tooth, or a bicuspid 
 
 Fig. 161. 
 
 Fig. 162. 
 
 Fig. 163. . 
 
 Fig. 165. 
 
 Fig. 166. 
 
 front, is then ground, l)acked, and adjusted on the cap to repre- 
 sent the labial aspect, and secured with wax. The front and 
 cap are then removed, invested, and soldered, after which they 
 are adjusted in the mouth, and the occluding edge of the por- 
 celain is ground clear of the antagonizing teeth (A, Fig. 161). 
 With a die of suitable size representing the occluding sur- 
 face of a bicusjiid, as illustrated in Fig. 162, a thin piece of pure 
 gold i>late is swaged (Fig. 163) and the cusps filled in with 18- or 
 20-carat gold plate. The cap is then trimmed (Fig. 164). ground, 
 and fitted to the occluding edge of the porcelain front (Fig. 165) 
 in proper position as regards occlusion, and the wax attaching 
 it is shaped to the contour of the crown (A). A piece of pure 
 gold plate (B), not over 34 or 35 U. S. standard gauge, is then 
 adjusted on each side of the crown, which is invested (Fig. 166). 
 The long ends of the t\vo side-]tieces of gold plate are desio-nod 
 to retain them in position, as the investing material should be 
 removed from tlu' portion inclosing the sides of the crown (A). 
 In the jirocess of soldering the solder is placi.'d in the aperture 
 
88 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 at B, and tlie flame of the blow-pix)e V)eing directed on the ex- 
 posed sides of the gokl at A, the sokler is flowed into every 
 part, forming perfect continuity of structure of the metallic por- 
 tion of the crown. In finishing, the surplus gold is trimmed to 
 the contour of a bicuspid tooth. Fig. 167 represents the finished 
 crown. 
 
 The method descril)ed produces a perfect and artistically 
 formed crown, but simpler and quicker methods are practiced. 
 One of these is to build up the palatal cusp with several pieces 
 of gokl plate, which have been previously melted into the form 
 of small balls and flattened out on an anvil. These, laid in posi- 
 tion and united with solder, are shaped in finishing to represent 
 
 Fig. 167. 
 
 Fig. 168. 
 
 Fig. 170. 
 
 the palatal cusp (Fig. 168). Tlie porcelain front should be 
 backed so that the solder can be flowed over its occluding edge. 
 
 Another method is to extend the palatal part of the collar down 
 as shown in Fig. 169, and then fill in the space with solder. 
 In finishing, the gold is trimmed to the form of the croA\'n. 
 
 The method of construction of molar crowns ^vith porcelain 
 fronts is similar to that for bicuspids (Fig. 170). 
 
 Dr. StoiceU's Jlethotf. — A porcelain crown can be soldered 
 on the cap, according to Dr. S. S. Stowell's method, as follows : ^ 
 " The tooth used may be a Logan or an E. Parmly Brown crown 
 or an ordinary countersunk tooth, but in most cases the Logan 
 crown is preferable. The pin is first cut ofi", then the tooth is 
 ground to fit on the cap ; porcelain and the stump of the pin 
 being reduced alike evenly and smoothly, after which the stumji 
 of the pin is ground with a small wheel below the surface of 
 the porcelain (Fig. 171). The tooth is then invested (Fig. 172) 
 
 ' Dental Cosjnos, vol. xxix, page 641. 
 
ALL-GOLD COLLAR CROWNS COXSTRUCTED IN SECTIONS. 89 
 
 and pure gold fused on to the platinum pin, and while in a fluid 
 state it is with a wax spatula "spatted" down flat (Fig. 173). 
 The gold is then tiled or ground down even with the porcelain, 
 
 Fig. 171. 
 
 Fig. 172. 
 
 Fig. 173. 
 
 Fig. 174. 
 
 Fig. 175. 
 
 and at the palatal border the tooth is ground to bevel back until 
 the gold is reached (Fig. 174). The tooth is then secured in 
 place on the cap with wax cement (Fig. 175), the case invested, 
 and heated until the wax has melted and burned out. A small 
 clipping of thin platinum plate is crowded into the opening (Fig. 
 176) caused bv the grinding of the bevel on the crown. The 
 clipping of platinum serves as a lead for the solder, which fol- 
 lows it down into the countersunk cap, around the ends of the 
 dowels, and Anally attaches itself to the pure gold already at- 
 tached to the stum}) of the platinum pin. Fig. 177 rejtresents 
 the completed crown. A sectional view of a like crown (Fig. 
 
 Fig. 176. Fig. 177. Fig. 178. Fig. 179. Fig. 180. 
 
 
 178) also shows the organi/.ation in detail. A porcelain crown 
 can be used to re])resent any of the teeth in the same manner. 
 See Figs. 179 and 180." 
 
 ALL-GOLD COLLAR CROWNS FOR BICU3PID3 AND MOLARS 
 CONSTRUCTED IN SECTIONS. 
 
 The root and ci'owii liavingl)een ]»roperly pi'epared. tlie eollai' 
 is formed and adjusted as described at juige 80, and the edge 
 toAvard the antau'oniziuii- teeth trimmed, to fullv clear them in 
 
90 
 
 ARTIFICIAL CROWX- AXD BRIDGE-WORK. 
 
 Fig. 181. 
 
 oecliisioii. The collar is then slightly expanded toward the 
 oreluding snrfaee to eifect contour, removed, filled with plaster, 
 
 and adjusted in position. Fig. 181 rep- 
 resents a typical case. The antagonizing 
 teeth, having heen covered with a piece 
 of tin foil, are then occluded until the 
 plaster sets. The collar is then removed. 
 The surface of the plaster inside the 
 collar will give the impression of the 
 natural root or crown, and the outside 
 that of the antagonizing teeth. The latter furnishes an outline 
 of the grinding-surface of the crown. 
 
 The plaster is then trimmed and shaped to represent the cusps 
 and fissures of the natural tooth, enough of the surface l)eing 
 removed to allow fov the thickness of the plate that forms the 
 cap. Eeadjustment in the mouth will show the accuracy of 
 the occlusion. 
 
 A small tube of copper, a trifle larger in circumference tlu\n 
 the crown under construction, is filled with Melotte's " Moldine," 
 and the surface rubbed with soapstone. An impression of the 
 
 lower portion of the form of the 
 crown A to the line B, Fig. 182, 
 is then made in the moldine, 
 and a strip (^f paper wound 
 around the tube, extending 
 about an inch above the edge. 
 Fusible alloy is then melted and 
 })Oured into the mold, thus 
 forming a die. An indentation 
 is made with a |)unch in a 
 block of lead, into which the 
 die, when cold, is hammered 
 slightly beyond the inqiression 
 of the edge of the collar. By this method a die and a counter- 
 die (Fig. 183) can, with practice, be completed in five minutes. 
 Witli this die the cap is then struck up on the lead from a flat 
 piece of plate and fitted to the collar. A little of the surface 
 (jf the plaster in the collar may have to be removed, if, on trial 
 
 Fig. 182. 
 
 Fig. 183. 
 
 A, Fusible die. 
 
 B, Counter-die. 
 
 C, Plate to form the 
 c-up. 
 
ALL-GOLD COLLAR CliOWSS CONSTRUCTED IX SECT/OXS- 91 
 
 ill tlir mouth, rlie r-A\> is t'oiiiid a littlr 'Husli. Tlic crown, with 
 the }>laster still inside the collar, is then lixed in a solderinii" 
 clamp constructed as sliown in Figs. 184 or 185, which holds 
 tlie parts toiivther and permits tlie flame to reach all jioints. 
 Xo more solder should l)e used to unite the edges than the con- 
 tour re(piires, as an excess necessitates additional lahor in fin- 
 ishing. 
 
 Another method is, when the cap is stiT.ck up, to melt solder 
 into the cusps, and then adjust tlie ca]» in position on the collar, 
 tor which purpose some of tlie plaster underneath the cap must 
 l)e removed. A jet of flame from the lilow-pipe is then thrown 
 upon it in such a wav as to cause the solder to flow (hnvn on the 
 
 Fig. 184. 
 
 Fig. 18.",. 
 
 The frame of thi? clamp is formed of iron wire, and the 
 supi)ort for the crown of phxster, asbe.?tos, and marble-dust. 
 
 edge of the collar and fill the seam on the inside. The ohjeetion 
 to this method is that, when a large jtortion of the natural crown 
 is inclosed hv the gold, the solder will occasionally alter the inside 
 form of the fitted cap, causing a defect trouhlesome to correct. 
 
 Still another method is to adjust the collar in the moutli, and, 
 with a small piece of wax or impression-compound pressed 
 upon it, to take an impression and " hite," in which the collar 
 wnll he inil»edded and removed. With this a model and articu- 
 lation are made and the form of the c-ap shaped in wax. An 
 impression of the ca]i is then made, either in nioldiiie in a soft 
 state in a tuhe, or in plaster, and a die cast. The cap is stamited 
 on this die, then adapted to the collar hv the model, and the 
 crown finished. This method, which was first made known hv 
 Dr. N. W. Kingslev, is ado}»ted when it is preferahle to construct 
 the crown l)etween the visits of the ])atient. 
 
92 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 The methods deserihed insure a perfect occhision of the 
 crown ^^ith the antagonizing teeth. In the absence of antagon- 
 izing teeth, or when the general form of the grinding surface 
 permits it, the cap can be struck up with a die formed similar to 
 the one shown in Fig. 186, corresponding to the surface of the 
 tooth crowned, by laving a piece of plate on a block of lead and 
 liammering tlic die into it. The cusps are then tilled in, and 
 the edges of the inner surface of the cap ground level on the 
 side of a corundum-wheel. The entire circumference of the 
 edge of the collar is also leveled, and the cap adjusted and 
 
 Fig. 186. 
 
 Fig. 187. 
 / / 
 
 Fig. 188. 
 
 '^laui'- 
 
 soldered as already described. If the cusps of the cap were 
 filled in with solder, it will flow down and join the collar on the 
 inside ; if with gold plate, the cap and collar must be joined 
 with solder on the outside. 
 
 Another method of connecting a solid gold cap to a collar is 
 to cut the lower edge of the collar in several places (Fig. 187) 
 and bend it inward, over tlie crown or root. Then adjust and 
 clani]) the solid gold erown cap in pro])er position on the collar, 
 and till the ga}) (A, Fig. 188) around the edge of the cap with 
 solder. 
 
 Metallic caps, or forms of the occluding surfaces of teeth for 
 use in constructing crowns, are quickly made with the die-plate 
 shown in Fig. 189,^ " in winch are four groups of intaglio dies 
 ^ Dental Cosmos, vol. xxix, page 482. 
 
ALL-GOLD COLLAR CROWNS CONSTRUCTED IN SECTIONS. 93 
 
 representing, with distinctive correctness, the pecnliar cusps of the 
 upper and lower riglit and left bicuspids and molars. These are 
 indicated by the Hillischer notation, so that each form may be 
 
 easily identilied in practice. The hul)s A, 13 (Fig. 190) are of the 
 sizes shown, and are made of an alloy composedjof tin one part, 
 lead four i>arrs, melted togctht'r. The mold C' should be warmed, 
 the metal alloy poured in every hole, and the ovi-rilow wiped off 
 just before the metal stitfens : this will make the butts of the 
 
94 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 liubs sniootli and flat. After a minute or two the mold may 
 be rever^^ed, the hul)s shaken out, and the easting [)rocess eon- 
 tinued until a considerable number of hubs shall have been 
 made. In Fig. 191, a molar hub is shown in place on a piece 
 
 Fig. 190. 
 
 (jf No. 32 gold plate, which lies over the 6* (upper right first 
 molar) die. A succession of l)lows on the hul) with a four- 
 pound smooth-face hammer Avill drive the plate into the die, and, 
 at the same time, s[)read the hub metal from the die center to its 
 
 circumference, in such a man- 
 ^'^^- 1^'- ner that the plate will ])e 
 
 })erfectly struck up with the 
 least possible risk of being 
 cracked. Tlie iiattened hub 
 is seen in Fig. 192, which also 
 shows at D the ob^'erse of the 
 struck-u]) hub, and at E the 
 cameo of the struck-up plate, 
 having every cUvSp and de- 
 pression of 6" sharply defined. 
 The counter-die ])late (Fig. 
 180) is made of a very hard cast metal, M'hich will admit of 
 the striking up of many crown plates by the means descril)ed, 
 if tlie crown plates be not too thick and stiff. Of course they 
 should be aniu'aled before they are placed o\'er the die. 
 
ALL-GOLD COLLAR CROWNS CONSTRUCTED IN SECTIONS. 95 
 
 "In careful hands the die-])! ate should give clear cusp defini- 
 tions after years of use-. The counter-die plate is in some re- 
 spects similar to a stereotype ])late for printing, and the struck 
 impressions on twt) strips of thin plate will therefore a]>[>ear as 
 in Fig. 193, wherein their regular order is noticeable, as seen 
 from the cameo surface of the struck plates. 
 
 " The peculiar action of tlie huh in forming first the center of 
 the crown plate, and spreading from the center outwards, as the 
 hub is shortened under the hammer, until the die is overspread 
 by the plate and huh, with the result shown in Fig. 192, is an 
 essential feature of this process for obtaining easily and (piickly 
 the superior styles of coronal cameos shown. If a cusp or 
 
 Fig. 192. 
 
 aieHY 
 
 fissure should chance t(t crack in huhbiug, a small piece of 
 ]>late may l)e struck up o\er the fissure, and then soldered to the 
 original cap." 
 
 Fig. 194 represents a case of abrasion of tlic lower teeth, to 
 which all-gold crowns have been applied, as shown in Fig, 195. 
 In such cases, owing to the aggression of the occluding teeth, 
 the cap forming the occluding surface should be constructed of 
 gold and ])latinuni plate. An artificial plate replaces the upper 
 teeth. 
 
 The roots of a molar decayed apart at the bifurcation can 
 often be crowned ser\'iceably by making a cap for each I'oot 
 separately, ami then soldering the sides of the ca]i togt'ther (Fig. 
 196). Where one root is missing, the other can be crowned 
 siuii'lv. 
 
96 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Figs. 197 and 198 represent Dr. J. N. Farrar's cantilever- 
 crowns. He describes them as follows : Fig. 197 illustrates a 
 sectional view of three teeth, and an amputated first bicuspid 
 
 r"^' 
 
 L^ I 
 
 P=H f"* 
 
 It:- 
 
 I'r 
 
 h4 
 
 I-* J 
 
 ^'1 
 
 E-i 
 
 \^\ 
 
 root preserved by a screw, sho^\ang the application of the canti- 
 lever crown T, P, set upon the decayed second bicuspid and 
 made to project over to bridge the space^formed by the loss of 
 the first bicuspid, and resting in eontact with the cuspid so as to 
 
ALL-GOLD COLLAR CROU'XS CONSTRUCTED IN SECTIONS. 97 
 
 connect the broken line of niastieatin<i' snrtaees and prevent 
 tilting forward of the second l)icnspi(l. Fig. 19S ilhistrates the 
 appearance of two molars, the posterior half of one of which is 
 
 Fig. 194. 
 
 destroyed, showing also the ajiplication of two thimble-crowns, 
 which are constrncted so as to form a cantilever bridge over the 
 chasm by locking midway in such a maimer as to prevent tilting 
 
 Fig. 195. 
 
 ov sliding of surfaces. an<l at the same time be easily cleansed 
 by a (piill or thread. The abscessed root here shown was ex- 
 tracted.^ 
 
 ^ Dental Cosmos, vol. xxvi, No. 3. 
 
98 
 
 ARTIFICIAL CROWN- AND BRIDGE- WOMK. 
 
 COLLAR CROWNS HYGIENICALLY CONSIDERED. 
 
 The principal arii'unieiit against ferruled or collared crowns is 
 that they are productive of irritation to the peridental mem- 
 brane, ultimately causing its absorption and the exposure of the 
 collar. This would l)e theoreticallv and practically true of a 
 rough or porous substan'ce encircling the root, or of an imper- 
 fectly aild unskillfully adjusted ferrule 
 or collar which would by its presence 
 hold a position analogous to a calcareous 
 deposit, but no such comparison can be 
 made in regard to a perfectly fitted 
 collar, forming at its edge a smooth 
 and imperceptible union with the sides 
 of the root, and presenting a uniform 
 
 In case of 
 
 perfectly adapted collars, when any irritation of the membrane 
 exists, it will be found to result from such causes as usually 
 produce it when the natural crowns are present, namely, den- 
 tal concretions. A tarnished and unclean condition of the 
 surface of the gold of the collar will produce an irritation of 
 
 Pig. 197. Pig. 198. 
 
 and benign surface to the investing membrane. 
 
 the meml)ranes, whicli is a matter inde}>endent of the collar itself, 
 and easily remedied by cleansing and polishing the surface. 
 "Where an acid condition of the secretions of the mouth exists, 
 a collar of jilatinum and iridium, or one of gold and platinum 
 crown-metal, presenting the platinum surface, is suggested in 
 prefei'ence to gold, as these metals will not be afi:ected, but will 
 constantly present an untarinslied surface. 
 
CHAPTER YIII. 
 
 THE GOLD SEAMLESS CAP CROWISr. 
 
 This iiietliod consists in tlic use of a i>'ol(l seamless cap for the 
 eonstrnction of tlie re([uii'e(l root cap or crown. 
 
 INC1SOR3, CUSPIDS, AND BICUSPIDS. 
 
 Incisor, cusjiid, and l)icuspid erowns with porcelain fronts are 
 constructed hy tins method as follows: The natural crown !;< 
 li'round down to witliin ahout one-eiii'lith of an inch of the gwm 
 at the })alatal wall, or enouiJ-h to clear the anta^'onizing teeth 
 when occluded, and slanting' from the posterior edge of the 
 ])ulp-chaml)er to the cervico-lahial edge of the gum and slightly 
 under its margin if it is desirable to conceal the Joining of the 
 crown with the root. The sides are shaped the same as for a 
 collar crown (Fig. 199). A die of the end of tlie root is then 
 made. For this purpose an impression of the part is taken with 
 gutta-}»ercha on the end of a piece of wood 
 trimmed to the pro])er size, or by placing 
 the gutta-^ierclia in a tube formed of a strip 
 of copper about one and one-half inches in 
 length and tlu'ce-eighths of an inch in di- 
 ameter, cut out on the sides to the depth of 
 half an inch, with the flange for the ])alatal 
 side shortened (Fig. 200). The impivssion 
 thus taken will be coniined almost entirely 
 to the end of the root to be capped. When 
 
 the gutta-percha has cooled, a stri[» of paper is tied around the 
 wood or tube and a die cast with the fusibh- metal. "When cool, 
 the die is remo\ed from tlie molib and tlu' metal is trimmed, 
 with tik- and i-hisel, a little (k'cper than the gum has permitted 
 tlie impression of the root t(-» be tak(.'n, and without altering the 
 
 99 
 
 Fig. 199. 
 
 Fig. 200. 
 
100 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 form of the end of tlie root (Fig. 201). A counter-die is then 
 made hv punching a hole in a level mass of pure lead, and with 
 a few hlows of a hammer driving the die into it. 
 
 A cap of gold can be formed by placing a piece of gold plate 
 (preferably pure, ITo. 32 U. S. standard gauge) of suitable size upon 
 a block of lead, and with an oval-shaped punch one-fourth of an 
 inch in diameter gradually driving it into the lead until the gold 
 has assumed the shape of a cap about a quarter-inch in depth (A, 
 Fig. 201). The gold should be withdrawn from under the punch 
 and annealed several times during the process. Caps can also be 
 m.ade with a stamping press such as was introduced by Dr. J. J. 
 R. Patrick. (See page 107.) 
 
 Fig. 201 
 
 Fig. 202. 
 
 Fig. 204. 
 
 Fig. 203. 
 
 • The ca]» is then annealed and swaged on the die to the form 
 of ihQ end of the root (B, Fig. 201). The palatal portion of the cap 
 should be allowed to go well up under the free edge of the gum, 
 and at the cervico-lal)ial edge it can be, if preferred, cut out to 
 the edge of the root. In the process of adjustment, the edges 
 that fit under the gum should be marked and trimmed as 
 directed in describing the construction of a collar crown, and 
 then burnished close to the sides of the root and into the orifice 
 of the root-canal, forming a perfect-fitting seamless cap (Fig. 
 202). An iridio-platinum ])in is then fitted in the root-canal and 
 sol<lci-cd to the cap (Fig. 203), or aftervvai'd adjusted as in the 
 
THE GOLD SEAMLESS CAP CROWN. 101 
 
 construction of the gold collar crown with porcelain front (page 
 85), with which operation the remainder of the process of 
 construction is identical. Fig. 204 represents the completed 
 crown. 
 
 The advantages of this style of crown are, simplicity, as tlie for- 
 mation of a collar is avoided, and strength, as a large portion of 
 the natural crown can l)e left at the ])alatal side. This affords a 
 stronger and more reliable foundation than can be ohtained at 
 any other point, as the direction of the force in mastication is 
 forward at an angle ^\•ith tlie line of tlie root, and although the 
 gold of the cap, where it encircles the root at the cervi co-labial 
 edge, is entirely removed, the crown is still held securely. 
 
 In a paper on the sulijeet of preserving and utilizing this part 
 of the tooth, Dr. W. F. Litch, of Philadelphia, descrihes a 
 crowning operation.^ He constructed the cap of platinum by 
 slitting a piece of the plate in a number of places, adapting it to 
 the form of the end of the root, and then soldering the whole 
 together. 
 
 This operaticm was not, however, so easily or so satisfactorily 
 performed as the method above described, in which platinum, if 
 desired, can be used instead of gold, and the soldering done with 
 22- or 24-carat gold. In some respects pure platinum is pi*efer- 
 able to gold in capping roots, as it is less likely to be affected by 
 the secretions of the mouth. 
 
 BICUSPIDS AND MOLARS. 
 
 All-gold seamless crowns for bicuspids and molars that will 
 accurately fit the natural crown and root, and occlude projterly 
 with the antagonizing teeth, are easily and ([uickl}'' formed, it 
 sutficient of tlie natural crown remains to advnit of tempc^^ary 
 i-estoration of its contour with gutta-])erclia or any other suit- 
 able plastic material. Wlieu this has l)een done, an imjtression 
 of the restored tooth is taken in gutta-jiercha in a tube, as ex- 
 plained on page 99, and a die then formed of fusible alloy; or 
 a plaster model can be made from ;ni im[iression of the tooth 
 taken in wax, and a mold obtained from the model. 
 
 The [)reparati()n and shaping of the natural crown, to re- 
 
 ' Dented Cosmos, vol. xxv, No. 9, page 449. 
 
102 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 ceive the artificial crown, can then be proceeded with. Where 
 the natural crown is very badly decayed or broken down and 
 the method just described, is not practicable, the portion of 
 the natural crown or root remaining should be shaped and pre- 
 pared to receive an artificial crown. Then the form of the 
 cer^Hx is ascertained with a wire as described on page 81, and 
 an impression of the parts taken in wax, and the Avire form, the 
 twisted ends having been shortened, is carefully adjusted on the 
 wax at the cervical line. The plaster model, when made, will 
 show^ the wire slightly imbedded in the plaster. The plaster 
 should be trimmed to the inner edge of the wire, as that repre- 
 sents the exact form of the root (Fig. 205.) 
 
 Another method is to encircle and adapt to the form of the 
 root a strip of annealed copper, ISTo. 35 standard gauge, al)()ut 
 
 Fig. 205. "Fig. 206. 
 
 one-eighth of an inch wide. The co})per is then removed, the 
 ends heated and touched with resin and wax, the copper adjusted 
 on the root, and the ends cemented with a warm instrument. 
 An impression is next taken A\'ith plaster, in which the copper 
 band is removed in position. A model made from this iinpres- 
 jsioii, after the^copper is removed, presents the exact form of the 
 root. 
 
 From a " bite " taken in wax a plaster articulation is then made . 
 to the model. A hole is then drilled in the center of the form 
 of the root on the model to be crowned. In this hole, and over 
 the end of the root, a ball of soft plaster, slightly colored with 
 carmine, is placed, and the teeth of the articulation covered 
 with tin-foil closed on it. This, on separation, gives the outline 
 of the fonii of the ii-rindi no-surface for the crown. The sides of 
 
THE GOLD SEAMLESS CAP CROWX. 
 
 103 
 
 the plaster are then trimmed to the form of the crown, and the 
 whole carved in detail (Fig. 206). A.-^ the crown will always 
 stamp larger in circumference than the die, in proportion to 
 the thickness of the gold used, an allowance must be made 
 by trimming off a pro}»ortionate amount of the surface of 
 the model; otherwise the outer surface of the crown will he 
 larger than is desired. "\Ylien tlie ])laster model for the erown 
 is made, it is se])arated from the rest of the model at the dotted 
 line seen in Fig. 206 and trimmed in the form shown by the east 
 A, Fig. 207. From this model the die is made in a tul)e witli 
 moldine and fusil)le metal as described *at page 99. The cast 
 should always be lengthened at the neck, so that the crown 
 when constructed shall have a surplus in depth of gold to allow 
 for any trimming or shaping of the collar that may be required. 
 The counter-die (B, Fig. 207) is made by punching a hole in 
 
 Fig. 207. 
 
 Fio. 208. 
 
 Fig. 209. 
 
 a bloek of lead and hammering the die into it. 
 ^ The crown, wliich is usualh' formed of pure gold, 
 
 or gold slightly alloyed, or gold lined with very 
 thin platinum from Xo. 32 to Xo. 34, U. S. standard gauge, is 
 then made by first stamping a piece of plate (see page 105) in 
 the form of a cap of gold (A, Fig. 20S). This cap is then i»laced 
 on the cast and with the aid of the eounter-die (B, Fig. 207) 
 swaged to the form of the crown B, Fig. 20S. A piece of kid 
 leather should be used to cover and protect the gold from the 
 lead, and facilitate its removal from the counter-die. An allow- 
 ance for the thickness of the leather must be first made, by 
 driving it on the cast without the gold, into the counter-die to 
 enlarge it. If this is not done, the gold is liable to be torn in 
 the swaging. 
 
 Cuspid crowns from which a portion of the gold on the lalnal 
 
104 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 aspect is to be removed, or which are to he used entire as a 
 support for bridge-work, can usually be advantageously formed 
 with a seamless cap (Fig. 209). The necks of these crowns can 
 be contracted in fitting in a contracting plate, or slit, lapped, and 
 soldered, should the case so require. (For details of process of 
 adjustment and insertion, see "Process of Adjustment of Seam- 
 less Contour Crowns.") 
 
CHAPTER IX. 
 
 GOLD SEAMLESS CONTOUR CROWNS. 
 
 The artistic requirement of all-gold crown-work is, that it 
 shall reproduce the anatomical contour of the natural teeth. 
 This is usually accomplished by melting solder on the collar and 
 then trimming it to the form of the crown. A preferable 
 method is to shape the metal forming the sides of the crown by 
 swaging. This is easih' done in a crown formed in sections, but a 
 special process is re([uired in the construction of seamless crowns. 
 
 A contour crown can be made by placing a seamless cap on a 
 sectional die or mandrel of the shape of tlie tooth, first swaging 
 
 Fig. 210. 
 
 Fig. 2n. 
 
 Fig. -212. 
 
 r 
 
 1 ^ : 
 
 ^ 
 
 
 g; 
 
 J, 
 
 ^' 
 
 -_ - ■ -^ 
 
 |t 
 
 1 
 
 1 
 
 _u 
 
 thegrinding-surfaee on the mandrel and then stamping downward 
 on the straight sides of the crown with a cap iitted to the shank 
 part of the mandrel. But such a process, like many others, is too 
 complicated to be of any use to the dental practitioner. Tlie 
 sectional mold method here presented is simple, practical, and 
 general in its application. 
 
 To describe and illustrate the process, we will take one of 
 the most difficult crowns to construct, — a superior molar (Fig. 
 210). A natural tooth, or one made of plaster, is used as a 
 model. From this a sectional mold is made, as illustrated in 
 Figs. 211 and 212, in Babbitt's metal, zinc, or fusible alloy. 
 
 105 
 
106 
 
 ARTIFICIAL CROWN- AND BRIDQE-WORK. 
 
 Into the mold a cap of gold (Fig. 213) 23 to 24 carats fine is 
 adjusted, fitting tightly the orifice of the closed mold. The 
 mold is then placed in a vise, and the cap is expanded to the 
 general form of the mold by hammering into it a mass of cotton. 
 The gold is then swaged more in detail to the form, and with a 
 wood point or a burnisher revolved by the dental engine bur- 
 nished after the method of Dr. Herbst into every part of the 
 mold (Fig. 214). To facilitate the process, the mold should be 
 frequently opened, and the gold annealed. Fig. 215 represents the 
 completed crown. These results can l)e secured l:)y other styles 
 of molds : Fig. 214 illustrates one, but the principle is the same. 
 Another method is to form a fusible-metal die of the tooth to 
 
 Fig. 214. 
 
 Fig. 215. 
 
 be crowned, and, after having stamped the grinding-surface of 
 the crown, to reverse and swage the sides close to the die; the 
 crown is then relieved of the core (die) by heating to the melting- 
 point of the fusible metal and pouring it out. 
 
 For practical use, a variety of molds should be made from 
 natural teeth of different sizes and average forms to serve in 
 corresponding cases. The crowns should be contracted at the 
 neck more than their size and contour call for, so that the gold 
 will act as a tight-fitting band which will expand to the form of 
 the root as the crown is pressed up in the process of adjustment. 
 
 Caps of metal can be made in difirerent sizes and kept on hand 
 for use in this and other styles of crown-work by means of a 
 machine (Fig. 216) such as is used by jewelers for forming cap- 
 shaped pieces of gold, and in factories for making copper car- 
 tridges. The gold plate, cut into circular pieces, is pressed through 
 a steel die-plate, with punches gauged to the holes ; at each punch 
 a small portion of the gold is turned over, thus preventing its 
 
GOLD SEAMLESS CONTOUR CROWNS. 
 
 107 
 
 lapping or creasing (Fig. 217). Repeated annealing of the metal 
 is very necessary in this process. 
 
 Fig. 210. 
 
 Methods of Contouring Crowns constj-ucted in Sections. — In con- 
 structing a crown in sections, the collar can be first formed on a 
 
 Fig. 21 
 
 Fig. 218. 
 
 mandrel, then placed in a mold, and bur- 
 nished to the shape of the sides. The pro- 
 cess of its adjustment to the neck of the root 
 is then continued in the usual manner. 
 
 Another method is to stam[i or burnish up the collar on a die 
 representing the upper sections of a tooth, designated as the 
 middle and cervical third (Fig. 218). After contouring the 
 
108 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 collar, the cap is adjusted and soldered on. With a metallic 
 stamping- plate (see page 93) these caps are quickly made. 
 
 Process of Adjusfment of Seamless Contour Crowns. — A superior 
 molar — one of the most difficult teeth to operate on — will serve 
 as a typical case to illustrate this process. The crown or root is 
 first shaped and if necessary built down with amalgam, straight, 
 or tapering slightly on its sides toward the occluding surface, as 
 described at page 39. Guided by the shape of the natural 
 
 Fig. 219. 
 
 teeth, and measurements b}^ calipers — a pair of tweezers with 
 a screw as shown in Fig. 219 answers the purpose — -or by a 
 plaster model of the mouth, a gold crown of suitable form and 
 size is selected. The crown is then slipped over the end of the 
 prepared natural crown or root, and gently pressed and worked 
 straight upward, the gold at the neck of the crown expanding to 
 the form of the root until the edge meets the margin of the gum 
 (A, Fig. 220). A line (B) is then marked on the gold with a 
 sharp-pointed instrument, parallel to the margin of the gum. 
 Tlie crown is then removed and the edge trimmed off to this mark 
 
 Fig. 220. 
 
 Fig. 221. 
 
 or even with it (A, Fig. 221), using small curved scissors. This 
 process should be repeated, taking off a little at a time, until the 
 edge of the gold meets the gum evenly at all points, under the 
 free edge of which it is then pressed up, and if the occlusion 
 is correct a burnisher is passed around the cervical portion and 
 the gold burnished accurately to the root. 
 
 Although a crown can usually be expanded on the root to its 
 
GOLD SEAMLESS CONTOUR CRO]rNS. 
 
 109 
 
 Fig. 222. 
 
 form Iq the process of ailjiistrnent, the necks of natural teeth 
 vary so in proportion to the size of the crown that it otlen 
 becomes necessary to slightl}' expand the gold at the neck of a 
 contour crown. Tiiis is quickly and easily done, without alter- 
 ing or injuring the crown, as follows: Soften a mass of gutta- 
 percha, about the size of the crown, upon the closed ends of a 
 pair of clarap forceps, or an ap-- 
 pliance of similar construction. 
 Introduce the gatta-percha inside 
 of the neck of the crown, which 
 should be moistened to prevent 
 its adhesion. Then withdraw the 
 gutta-perrha, harden it i?i cold 
 water, and cut througli the center, 
 Ijetweeu the points of the forceps. 
 By reinserting the points of the 
 forceps armed with the gutta-per- 
 cha, the neck of the crown may 
 be expanded in any direction ac- 
 cording to the manner in whieh 
 the forceps and gutta-percha have 
 l)een inserted (Fig. 222). A gold 
 collar can be expanded in a similar 
 manner. 
 
 Before the crown is pressed up 
 to its apparently proper position, 
 the ocelusiou should be examined 
 and calculations carefully made to 
 obviate any defects, which at this 
 stage can be readily corrected by 
 proper manipulation of the crown. Any desirable change can 
 usually be made in the form of the occluding surface of the crown 
 while on the tooth, with an instrument tapped by the mallet, or 
 by removing the crown, holding it with the index finger pressed 
 flat against the edge of the cervical portion, the other fingers 
 grasping tlie sides, and tapping the gold with a riveting hammer. 
 The position can be changed for altering the sides, on which 
 the fiat end i»f the hammer should be used. 
 
110 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 ^Strengthening Seamless Gold Contour Croirns. — Additional 
 strength and stiffiiess can be given to seamless gold crowns 
 when desired, in several ways. The liability of melting the 
 gold which forms the sides of the crown in the operation has, 
 with some, been the principal objection to their use. This, 
 however, can be avoided. Where the cusps or grinding-surfaces 
 require filling in or thickening, which is done from the inside,, 
 it is safely accomplished as follows : Take a pellet of moldine/ 
 moisten it with water, and work it until quite soft, then roll it 
 out lengthwise, and envelop the crown on its sides with a very 
 
 Fig. 223. Fig. 224. Fig. 225. 
 
 <dL!»>, 
 
 thin continuous piece, leaving exposed the parts of the occlud- 
 ing surface that are to be tilled in. Pass around on the outside 
 of the moldine, without touching the crown, a fine wire, and 
 twist the ends together for a handle (Fig. 223). Grind some 
 borax mixed with water to a cream-like consistence, and with a 
 small pellet of cotton twisted on an instrument paint the inside 
 of the crown with the borax just where you wish the solder to 
 flow. Then place inside the cusps an easy-flowing solder that 
 has been cut tine and immersed in the borax. The crown is then 
 held in the flame of an alcohol lamp or in a blue gas flame, and 
 heated slowly so that the position of the solder will not be 
 changed by the fusing of the borax. Increase the heat until 
 the solder flows over the surface of the gold, which it does very 
 quickly when the melting-p()int is reached. Then the crown 
 must be instantly removed and examined. Sufficient solder 
 should be placed in the crown to give it the desired strength in 
 one heating, but in case of necessity more can be added and the 
 process cautiously repeated. The moldine protects the sides, 
 which generally take up the greatest degree of heat. 
 
GOLD SEAMLESS COXT(fUR CROWNS. Ill 
 
 Another method for streiigthenino; or tilHng gold seamless 
 crowns with solder or even 18- or 20-carat gold plate, is to invest 
 the outside surface of the crown in plaster and marble-dust 
 (Fig. 224), and then with a small flame of the earbo-oxyhydro- 
 gen blow-pipe, not over one-half an inch in length, introduced 
 inside of the crown, melt and flow the solder or gold plate 
 over any portion or even all of the surface of the gold. The 
 crown, if formed of gold with a thin lining of platinum, can be 
 soldered by either method with little danger of being melted. 
 
 If for some special purpose it is desirable to strengthen the 
 neck of a crown by increasing the thickness of the gold, it is 
 first soldered to stiflen the occluding surface as above described, 
 the investing material is then removed, and the inside of the 
 crown filled solid with moldine or investing material. The gold 
 which is dulled on the surface is scraped around the crown, 
 along the line of the cervical edge (A, Fig. 225), only as low as ' 
 the stiflening is required. Along this part, borax is applied with 
 a brush, and small pieces of 20-carat solder placed in succession 
 and melted, the crown being turned during the process until the 
 neck is entirely encircled. 
 
 Supporiing the Croion. — In crowning teeth with living pulps 
 there is sufficient of the natural crown present to aftord a secure 
 foundation and attachment for the artificial crown, as is also the 
 case with many teeth that are pulpless ; but in badly broken- 
 down crowns, or where only the root is present, a metallic pin 
 or post should be inserted in the root, and the part 
 built down with amalgam to a form that will afford 
 secure support and attachment to the artificial crown, 
 and facilitate its adjustment. (See " Special Prepa- 
 raticrn of Badly-Decayed Teeth or Roots," page 39.) 
 
 In many cases the required support for the crowu 
 can be secured by means of a screw (Fig. 226). 
 A How screw is inserted in the root-canal A (see 
 page 52). Amalgam is then packed in the lower 
 section of the artificial crown, C, to the line B, and 
 into the amalgam the screw is pressed. Amalgam which has 
 been put in a piece of cliamois and the mercury pressed out 
 with a pair of pliers untii it is 'In the condition termed '' dry "'' 
 
112 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 will adhere to the gold without affecting it. The amalgam is 
 first placed in the crown slightly in excess of the amount re- 
 quired, and the crown adjusted, removed, and the surplus 
 scraped out. This process is continued until the screw or the 
 crown section of the natural tooth forms an indentation in the 
 amalgam, which it will fit when the crown is cemented on. The 
 vent for the escape of air and surplus cement — which should 
 always be put in perfect-fitting crowns and afterwards filled with 
 o;old or amalo;am — should be in the line of the indentation in 
 the amalgam, with which it must connect (D). (For process of 
 pementation, see article on " Insertion and Cementation.") 
 
 These crowns can be inserted in an easy and inexpensive man- 
 ner by filling in the lower section of the crown with amalgam 
 instead of gold, and allowing the head of the screw or the nat- 
 ural crown to indent the amalgam as al)ove described, and then 
 cementing on the crown with oxyphosphate in the usual 
 manner. 
 
 In a case so inserted, with no antagonizing teeth, the result is 
 
 the same as though the inside of the occluding surface of the 
 
 crown was filled with gold ; but if antagonizing teeth are present, 
 
 the soft gold of the crown is apt to M'ear through in places and 
 
 -—expose the amalgam. 
 
 If a tooth is short and the articulation such as to require the 
 
 reduction of the collar to a size which will suggest insecurity 
 
 when the crown is cemented, or if tlie tooth is pulpless, a 
 
 headed or barbed pin that will anchor in the root should 
 Fig 227 ..... 
 
 be soldered in the interior of the crown, as shown in 
 
 Fig. 227. This is done by passing the pin through a 
 liole made in the occluding surface of the crown, adjust- 
 ing the crown in the mouth, removing, investing, and 
 soldering the pin from the outside surface of the crown. 
 The advantages of seamless contour crowns are, that they 
 represent perfectly the tooth in its anatomical contour, present a 
 uniform surface of pure gold, which preserves its color without 
 tarnishing, and are quickly and easily adjusted. Their defects are 
 inability to meet the requirements of abnormally-shaped roots 
 and anomalous ai'ticulations. 
 
CHAPTER X. 
 
 GOLD CROWNS WITH PORCELAIN FRONTS FOE TEETH WITH 
 
 LIVING PULPS. 
 
 In the anterior teeth, in case of atrophy or erosion, or where 
 decay has destroyed the approximal sides of a tooth in such a 
 manner that crowning is considered the most desirable operation 
 to perform, the pulp is frequently found unexposed and in a 
 normal condition. The importance of its preservation in such a 
 case is unquestionable. 
 
 Tlie methods at present most commonly used to form a crown 
 under such conditions are in many respects defective and 
 objectionalile, notwithstanding the advantages their indorsers 
 claim for them. 
 
 In the tirst place, all crowns of platinum and iridium, with 
 body baked on to represent the labial aspect of the tooth, have a 
 dead and unnatural appearance, and from those on which jGdms 
 of porcelain representing teeth are l)aked the porcelain fre- 
 quently chips off, and both styles usually protrude beyond the 
 line of the adjoining teeth. 
 
 The method here presented is intended to overcome these 
 objections and to produce a more satisfactory result. The des- 
 criptive details of the crowning of a central incisor will serve to 
 illustrate it. A model is tirst made representing the tooth in a 
 perfect form. This can be done either by shaping the natural 
 tooth in the mouth with oxyphosphate or gutta-percha, taking 
 an impression of it in wax oi- moldine, and forming a model 
 in plaster or fusible alloy, or by taking a natural tooth and 
 shaping it to correspond, or, if the operator is an expert, carving 
 one from a piece of i)laster. 
 
 Two casts, one of the coronal form of the tooth (Fig. 22H), 
 and the other of only the palatal and approximal portions (Fig. 
 
 8 113 
 
114 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 229), are made, using the moldine in tubes with fusible metaL 
 This will consume only a few minutes. A piece of gold and 
 platinum crown plate, iSTo. 34 U. S. standard gauge, about the 
 length and circumference of the tooth, is then struck up on the 
 palato-approximal cast, from which it receives the palatal and 
 approximal aspects of the tooth. It is then transferred to the 
 coronal east, which is previously trimmed the thickness of the 
 gold plate upon the approximal surfaces, and worked down to 
 the exact form of the tooth on the anterior portion (Fig. 230). 
 The metal, which is then the exact form of the tooth on all 
 sides, is cut even at the incisive edge, the seam down the front 
 beveled, lapped, and marked, then slightly opened, and the gold 
 slipped oiF the die. Guided by the mark, the gold is then 
 
 Fig. 228. 
 
 Fig. 229. 
 
 Fig 2.S0. Fig. 231. Fig. 283. {-^ 
 
 yj! 
 
 U 
 
 Fig. 232. 
 
 pressed back to the form assumed on the die, and fitted to the 
 natural crown, which should have been previousl}^ trimmed and 
 shaped as described on page 38 (Fig. 19), and the joint on the 
 labial side soldered (Fig. 231). Into the incisive edge, which is 
 open, a narrow strip of gold, about one-sixteenth of an inch in 
 width and thick enough to fill the space, is fitted and soldered. 
 This strengthe*is the whole crown, and forms a protecting edge 
 for the porcelain front. 
 
 We have now a gold-contoured crown, an exact imitation of 
 the tooth under treatment. The crown is then filled with 
 plaster, and the labial ]>ortion ground and filed away, so as to 
 leave the upper part to form the band, and the lower the in- 
 cisive edge, as represented in Fig. 232. 
 
 A porcelain tooth which matches in shade and form is then 
 ground and thinned down — in which operation the pins are 
 removed — to the form of a thin porcelain front, thickest at the 
 
GOLD CROWNS WITH PORCELAIN FRONTS. 115 
 
 incisive edge. This front is fitted to replace and represent the 
 lal)ial portion. The porcelain is then removed and a piece of 
 platinum foil adapted to its back, and turned just barely over 
 the edges, the upper and lower of which should be slightly 
 tapered off, as shown in Fig. 233. 
 
 The platinum can be made to lit closely to the porcelain by 
 rubbing the edges on a piece of cloth or chamois, on a Hat 
 surface. The porcelain front is then adjusted on the crown 
 and cemented on one side with wax, and the crown invested in 
 plaster and marble-dust, so that the seam along the edge of the 
 platinum and gold is exposed on the cemented side and at one 
 end as shown in Fig. 234. The investment is then heated and 
 the seam soldered with small pieces of 20-carat solder. Care 
 must be taken not to flow the solder upon the porcelain, or to 
 
 Fig. 234. Fig. 235. Fig. 236. Fig. 237. 
 
 use more borax than is absolutely necessar}', as otherwise the 
 porcelain will be fractured. 
 
 When the investment is cold, the crown is removed, again 
 invested, and the remainder of the seam soldered, or the invest- 
 ment <.-iu\ be immediately removed from the other side, and the 
 soldering completed ; though this latter plan is attended with 
 some risk to the porcelain. 
 
 After the crown has gone through the finishing process, the 
 excess of porcelain inside of the crown is ground away in a few 
 minutes with a small piece of corundum melted on an old oval- 
 shaped bur. The cavity in the crown is, meanwhile, kept filled 
 with water (Fig. 235). 
 
 In adjusting the crown, tlie natural tooth can be smeared with 
 articulating [)aste, which will easily indicate any point obstruct- 
 ing its perfect adaptation. When fitted, the crown is attached 
 witli oxy phosphate .cement. Fig. 236 shows the completed 
 I'rown. 
 
116 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 238. 
 
 Bicuspids and molars can be made in the same manner by 
 using a contour crown of gold lined with platinum (see chapter 
 on contoured crowns), and, after its adjustment, fill- 
 ing in the crown with plaster, and then cutting aAvay 
 the labial portion and replacing it Avith p)orcelain 
 (Fig. 237). 
 
 Croirnin'/ in Cases <if Ahi'dskm. — In a case of ex- 
 tensive abrasion of the incisive edges of the antei'ior 
 teeth, with pulp living though considerably calcified 
 in the coronal section, crown-work to restore the 
 length and form of the teeth is best performed by 
 removing a portion of the labial aspect of the natural 
 crown and then forming the artificial crown similar 
 to a gold collar crown without the pin. An accurately adapted 
 collar, cemented with oxyphosphate, will secure the crown suffi- 
 ciently. Fig. 238 gives an outline of the construction of such a 
 crown. 
 
CHAPTER XL 
 
 SPECIAL FORMS OF GOLD CROWNS WITH PORCELAIN FRONTS. 
 THE PARR CROWN. 
 
 This crown, which in form of construction possesses special 
 points of merit, is largely used by Dr. H. A. Parr. 
 
 The root is prepared, banded, and capped without a pin, the 
 same as for a gold collar crown (A, Fig. 239). A hole is made 
 in the cap, and a post fitted in tlie canal. A piece of gold plate, 
 fully the size of the cap on the root, is adjusted on the post 
 above the cap by making a hole in the gold in which the post 
 will fit tightly. The gold plate is then adapted to the cap on the 
 
 Fig. 239. 
 
 Fig. 240. 
 
 Fig. 241. 
 
 root, and burni.shed into any open ,-pace around the post, 
 
 forming an outside cap ; the pin and the outer cap are 
 
 then removed and soldered together and adjusted on 
 
 the inner cap, and the edge of the outer cap trimmed even with 
 
 it (B). The porcelain tooth to form the crown, C, is fitted and 
 
 attached to the outer cap, which, when finished, is cemented 
 
 in position as shown in Fig. 240. 
 
 The advantage of this form of crown is that the root is 
 securely and permanently capped independently of the crown, 
 which can be removed without disturbing the cap on the root. 
 
 117 
 
118 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 Fig. 242. 
 
 Dr. Parr, in using this style of crown in bridge-work, constructs 
 the outer cap with a band which half encircles the inner cap, 
 and tapers off from the palatal to the labial section, as illustrated 
 in Fig. 241. The cap on the root is cemented with oxy phos- 
 phate, and the post and outer cap with gutta-percha. 
 
 THE LEECH CROWN. 
 
 Dr. Leech's crown is thus described bv Dr. J. E. Dexter:' 
 "A method devised by Dr. H. K. Leech, of Philadel]>hia, 
 
 shown in Fig. 242, and described in 
 the Denial Cosmos for April, 1879, is 
 as folloAvs : The root is drilled out to 
 a depth of about three-eighths of an 
 inch to a diameter of about jSTo. 16, 
 standard (American) wire gauge, the 
 bottom of the hole being flared or 
 enlarged, and the canal above tilled 
 with gutta-percha. A gold tube is 
 made to fit the hole accurately and 
 project sufficiently for convenience of 
 handling, and is soldered throus;!! a hole in a iJ-old base struck 
 to the root, projecting through the plate some distance. A plate 
 tooth is fitted to the root and plate and soldered to the latter, 
 gold being flowed onto the plate and backing and around the 
 projecting tube to form the palatal contour, and the tube cut ott" 
 flush with the latter. We now have a plate tooth, gold backed, 
 with a tube-pivot, the orifice of which opens on the })alatal 
 aspect of our tooth. The root-end of the tube is now slit per- 
 pendicularly in three pr four places, for about two-thirds of its 
 length, a thin sheet of warmed gutta-percha is placed on the 
 base of the croAvn around the tube, and the whole is pushed 
 securely to place. Now pack gold or tin into the tube, coiv/enmif/ 
 the bnUoin j)OrHoris so fhut the slit end irill spread and Hf/Jdly Jdf f/ic 
 flared end of the Inile in Ike root, and the operation is complete." 
 
 A collar crown fastened with a tube-pivot as described can be 
 used to advantage in detachable bridge-work, as the tube if 
 filled with tin foil will admit of the crown beiiiii' easily detached. 
 
 ^Denial Cosmo.", May, 1883. 
 
THE LOW CROWN. 
 
 119 
 
 THE LOW CROWN. 
 
 In the method for crowninti' pnli»less roots of Dr. J. E. Low, 
 of Chicau'O, the root-eaual is reamed out with an instrument 
 which at the same time shapes the end of the root, or a portion 
 of it, to receive a combined post and cap, which the inventor 
 
 Fig. 243. 
 
 Fig. 244. Fig. 245. Fig. 246. 
 
 calls a " step-plug," from its peculiar form. There are seven 
 sizes of the cutting instruments (Fig. 243), and corresponding 
 exactly with them seven sizes of the step-plugs. These stej)- 
 plugs are not unlike a minute cone-})ulley set in a saucer-shaped 
 cap upon the bottom of which is a stout boss. They are nuide 
 of platinum and nickel. As these last lit the ]U'epared root 
 accurately, it is claimed that they 
 afford a secure foundation for the 
 artiiicial crown and also jircveut 
 longitudinal fracture of the root. 
 
 To describe and illustrate the ])ro- 
 cess, the root of a central incisor (Fig- 
 244) is selected. The end of the 
 
 root is first ground level with the |)alatal margin of the gum. A 
 cutting instrument of suitable size is then selected, with which 
 the root is shaped as shown in Fig. 245. The end of the root is 
 removed enough to permit the palatal edge of the cap of the step- 
 plug (Fig. 246). which is then adjusted, to pass just below the 
 
120 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 margin of the gum. Fig. 247 shows the step-plug in position, and 
 ready for the adjustment of the porcelain front (Fig. 248) and 
 the construction of the crown, which is completed as in methods 
 previously described. The porcelain front when adapted should 
 meet the labial margin of the gum, and when necessary the 
 lalnal surface of the end of the root should be trimmed, with 
 the cap in position, with a corundum-wheel to permit it. When 
 the porcelain front is to l)e adjusted in the mouth, the backing 
 should be warmed, a small quantity of resin and wax cemented 
 u})on it, the tooth placed in position in the mouth, and the con- 
 vex surface of the step-plug cap perfectly imbedded in the wax. 
 The wax and the porcelain front should next be carefully removed 
 
 Fig. 247. 
 
 Fig. 250. 
 
 Fig. 252. 
 
 Fig 254. 
 
 Fig. 251. 
 
 Fig. 253. 
 
 Fig. 255. 
 
 and then the step-plug, using pliers for the last. The step-plug 
 is then to be placed in the Avax impression, to which it is fixed 
 with a heated s})atula, and then invested for soldering. Fig. 249 
 shows the completed crown ready for final adjustment, and Fig. 
 250 gives a sectional view of it in position. 
 
 In crowning bicuspid roots, one step-plug placed in the 
 palatal side of the root (Fig. 251) is usuallj^ sufficient, the 
 remaining exposed surface of the end of the root being covered 
 by adapting thin platinum plate over it and on to the surface of 
 the cap before adjusting the porcelain front (Figs. 252 and 253). 
 Figs. 254 and 255 show the completed bicuspid crown before 
 and after the final adjustment. Molar roots are capped in a- 
 similar manner, using two step- plugs. 
 
 The plugs are useful in building up badly-decayed roots to 
 support and retjiin all-gold crowns. 
 
CHAPTER XII. ■ 
 
 CROWNING FRACTUKED TEETH AND ROOTS, AND IRREGULAR 
 
 TEETH. 
 
 The crowning of fractured teeth and roots is a process that 
 requires skill and delicate treatment. Its practicability depends 
 on the nature of the fracture, the previous health of the parts, 
 and the length of time that has elapsed since the occurrence 
 of the injury. 
 
 LONGITUDINAL FRACTURE OF THE CROWN AND ROOT. 
 
 B}^ this is meant a fracture of the crown or what remains 
 of it, longitudinally through it, and down the root or roots. 
 Foreign substances having been removed from within and around 
 the parts, the crevice of the fracture is syringed thoroughly 
 with a solution of carbolic acid and tepid water. The fractured 
 parts of the root are then drawn together with waxed floss Fig. 2o6. 
 silk, passed at least twice around the tooth, and tied, the -^J^T^^ 
 ends being passed through twice in forming the knot. J^J 
 The pulp-chamber is then prepared, and dovetail slots ^>— — ^ 
 drilled across the parts (Fig, 256). If it is suspected that any of 
 the particles removed in the preparation have invaded the crevice 
 of the fracture, the ligature must be removed, the parts again 
 syringed, and the ligature readjusted. The upper parts of the 
 root-canals are then tilled with gutta-percha, and the main body 
 of the cavity and the slots with a hard, quick-setting amalgam. 
 At the next visit of the patient the ligature is removed and the 
 parts carefully prepared for crowning. The circumference of 
 the root is lirst measured with a wire, a tight-fitting collar con- 
 structed, and the crown then completed in the usual manner. 
 
 The great drawback in these cases is that the patient generally 
 fails to present himself immediately for treatment, and foreign 
 substances work into the fracture, causing inflammation, which 
 
 121 
 
122 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 is difficult to control. Often sul)se(j[uent to treatment a septic 
 condition of the fracture supervenes, the irritation caused thereby 
 and the exudations from the fracture becoming so annoying that 
 extraction is the only alternative. 
 
 Teeth fractured as above descril)ed rarely have living pulps. 
 
 FRACTURE OF THE CROWN, WITH SLANTING FRACTURE OF 
 
 THE ROOT. 
 
 Fractures of this kind are common, especially in bicuspids, 
 where large fillings are inserted extending from the anterior to 
 the posterior approximal walls, leaving the separated buccal and 
 palatal cusps to bear the force in mastication. 
 
 In such cases the fracture seldom extends beyond the edge of 
 the alveolar process. The fractured part having been removed, 
 
 Pig. 257. 
 
 Fig. 258. 
 
 Fig. 259. 
 
 a dovetail slot is made in the crown or root, into which gutta- 
 percha is inserted for a day and the membrane of the gum pressed 
 back, so as to fully expose the surface of the fracture. The form 
 of the root is then in a measure restored with amalgam, which, 
 when hard, is polished (Figs. 257 and 258). 
 
 The root is then crowned tlie same as in any other case. 
 
 METHODS OF CROWNING IN CASES OF IRREGULARITY. 
 
 Fig, 259 shows a method of treating a case of irregularity 
 without destroying the vitality of the pulp. The tooth at B, 
 which stood inside the line of the lower teeth when the mouth 
 was closed, was trimme<I, shaped, and capped. To this cap was 
 
CROWNING IN CASES OF IRREGULARITY. 
 
 1-23 
 
 attached the tooth at A, with an oval-sha]:»ed piece of gold that 
 cleared the lower teeth in occlusion. The cap was then cemented 
 to the natural crown. 
 
 Fig. 260 represents a case of irregularity treated by Dr. 
 Bonwill, who says in his description of it, — 
 
 '' This shows a case of irregularity which was beyond correc- 
 tion, on account of the poor character of the teeth, their position 
 in the palatal arch, and the age of the patient. In such cases I 
 
 Fig. 260. 
 
 do not hesitate to cut otf the crown, destroy the pulp, and place 
 one of the plate tooth-crowns with a nut. To do so, the crown 
 must be connected to the root by a strip of heavy gold plate, 
 extending for one-quarter of an inch or more, to bring the artificial 
 crown into the circle. For such cases the porcelain crown will 
 also answer." 
 
CHAPTER XIII. 
 
 PAETIAL CEOWNS. 
 
 Gold. — Partial crowns of gold for the protection of plastic 
 fillings in large cavities and for the restoration of contour are 
 often desirable when, for any reason, a solid metallic filling cannot 
 well be inserted. The cavity having been properl}^ excavated, 
 its orifice is trimmed as uniformly straight or circular as its 
 position and character -will allow, and the edge of the enamel 
 beveled off", tapering towards the center. In the preparation of 
 cavities in the grin ding-surface, trimming and cutting away the 
 enamel should be confined to that surface. In approximal 
 cavities which reach the grinding-surface, it is advisable to 
 extend them in that surface and bring the gold over 
 Fig. 261. and anchor it there, so as to afiibrd greater security 
 against its displacement in mastication. "Where de- 
 cay extends close to the margin of the gum, if the 
 tooth is trimmed away so that the gold will extend just 
 under its free edge, a recurrence of decay at that 
 point will be avoided. The bicuspid shown in Fig. 261 will 
 serve as a typical case to illustrate the constructive details. 
 
 The cavity having been properly prepared, a die of the tooth 
 in its original form is then secured. For this purpose the mold 
 is made by taking an impression of the tooth with wax, making 
 a plaster model, and then restoring the contour and forming 
 from it the mold in gutta-percha or moldine ; or the shape of the 
 natural tooth may be restored with wax or gutta-percha and the 
 iiiokl made directly from it in plaster. The die and counter- 
 die having been formed (see article on " Molds and Dies "), a 
 piece of pure gold,]Sro. 28 to 30 standard gauge, the exact thickness 
 being governed by the size and nature of a cavity, is struck up to 
 the form and size of the part to be capped. The gold is then 
 124 
 
PARTIAL CROWNS. 
 
 125 
 
 Fig. 262. 
 
 Fig. 263. 
 
 adjusted to the cavity, and the edges trimmed and hurnished 
 tf> fit close and flush with the edges of the cavity. In the case 
 of large cavities including a part or the whole of the approximal 
 surface, a model of the tooth and the empty cavity from an impres- 
 sion taken in wax will sometimes facilitate and guide the pre- 
 liminary trimming and shaping of the gold. Two headed pins 
 fixed on the inside of the cap (Fig. 262) are generally sufficient 
 to secure it, but others can be added if the con- 
 ditions of the case seem to require it. In com- 
 pound cavities, including the side and grinding- 
 surface, one pin at least should be fixed in the 
 latter portion. A¥here the grinding and both 
 approximal surfaces are included, a wire should 
 be extended from one side to the other (Fig. 263), 
 but the fastening should not touch the bottom of 
 the cavity. 
 
 In pulpless teeth the pin from the upper part of 
 the cap should extend up the canal, giving great 
 stability in such cases (Fig. 264). 
 
 In soldering the pins or loops when inserted in 
 holes drilled in the gold, a little solder can be flowed 
 over the adjacent parts if deemed necessary to 
 stiffen and strengthen them. 
 
 Oxyphosphate is, as a rule, the best to be used 
 in connection with these caps, as it forms a solid 
 and unyielding foundation, ynd, when properly 
 protectfd from the fluids of the mouth by a care- 
 fully adjusted cap, is very durable. 
 
 The cement should be first inserted in the cavity, 
 and then a small quantity placed around the pins 
 of the cap, which should be immediately adjusted accurately 
 in position. When gutta-percha is used, it is heated and applied 
 in the same manner to cavity and cap. The cap is then heated, 
 pressed into position, and held there until the gutta-percha 
 hardens. This can be hastened by the application of cold 
 water from a syringe. The surplus of gutta-percha is then 
 removed, and the edges of the gold burnished. 
 
 These caps applied to cases with living pulps show durability 
 
 Fig. 264. 
 
126 
 
 ARTIFICIAL CROW 2^- AND BRIDGE-WORK. 
 
 of a commendable character. The advantage they possess over 
 pieces of porcelain is found in the close joint that can be made 
 with the edge of the enamel by burnishing the gold against it. 
 
 Porcelam and Gold. — The partial restoration with porcelain and 
 gold of an incisor crown such as is shown in Fig. 265 is often desir- 
 able. The edges of the crown to form the joining with the porce- 
 lain are trimmed straight and level, and then polished. A shallow 
 groove is generally formed to advantage at A, Fig. 266. A very 
 
 Fig. 265 
 
 Fig 266. 
 
 Fig. 267. 
 
 Fig. 268 
 
 Fig 269. 
 
 Fig 270. 
 
 thin piece of plaiinum is then adapted to the crown as shown at B, 
 Fig. 267. The pin C is fitted to the root-canal, passing through 
 the platinum. The post and cap of platiniun are then attached 
 with wax, removed, invested, and soldered with pure gold. A 
 little of the gold at the same time is flowed over the cap. The 
 
 cap and post are then adjusted to the 
 crown, and the cap is trimmed level 
 and burnished so that it fits closely 
 against the surface of the fracture 
 and into the groove at A, Fig. 266. 
 At this stage of the work, to facilitate 
 the subse(|uent operations, an im- 
 pression can be taken that Avill re- 
 move in it the cap, and from this a 
 model can be made. A cross-pin 
 porcelain tooth is then ground down to a size and shape that 
 will properly restore the part and form an accurate joint with 
 the labial edge of the natural crown. The porcelain is then 
 backed, cemented to the cap, removed, and soldered wdth 20-carat 
 solder. The partial crown when properly finished is cemented 
 in position with oxy phosphate. 
 
 In a case such as is represented in Fig. 268 the cap is shaped 
 
PARTIAL CROU'XS. 127 
 
 to the surface of the fracture at A and o\er its palatal edge, and 
 the backing on the porcelain is extended out over the palatal 
 edge of the fracture at B. The two sections of the platinum 
 are united in the soldering. 
 
 Fig. 269 illustrates a fractured central incisor in which the 
 pulp was not exposed, restored with [»orcelain by Dr. J. Bond 
 Littig, of New York. The cap to the fractured part was fastened 
 by three small pins as shown in Fig. 270, which illustrates the 
 details of the' construction. 
 
CHAPTER XIV. 
 
 FINISHING AND POLISHING— PROCESS OF CEMENTATION. 
 FINISHING AND POLISHING CROWN-WORK. 
 
 The finishing should be done with small corundum-wheels 
 and points, first coarse, then fine, on the dental engine, which, 
 for this part of the work, is preferable to files or the lathe. In 
 the final finishing use moose-hide points with fine pumice on 
 the engine, or felt wheels on the lathe ; and, in the polishing, a 
 brush wheel, with whiting and rouge on the lathe. 
 
 The gold should first be properly shaped, which includes 
 trimming the collar ofif to a fine edge where it fits under the 
 gum, so that the seam of union with the root will be impercep- 
 tible. The gold that has been placed on the incisive edge of the 
 incisor and cuspid crowns should be trimmed away, so that 
 although it will protect the porcelain, very little if any will be 
 seen when the crown is in position in the mouth. 
 
 INSERTION AND CEMENTATION. 
 
 In the insertion and cementation of all crown- and bridge-work, 
 the object to be eftected is the same in principle, that is, to form 
 with an insoluble material a solid, substantial, and impervious 
 union between the natural tooth or root presented and the arti- 
 ficial crown. As a cement for this purpose, the plastic oxyphos- 
 phate of zinc is generally i)referred, and it is in many respects 
 one of the most desirable to be found. 
 
 Exact scientific proportions of the chemical substance of which 
 the cement is composed are essential in its preparation, and the 
 oxide of zinc should be in a very fine povT'der. A standard pre- 
 paration of the cement should be selected. For all styles of crowns 
 with collars, and for bridge-work depending on crowns of similar 
 con.struction, slow-setting cement should be used, but for crowns 
 128 
 
INSERTION AND CEMENTATION. 129 
 
 without a ferrule or collar the ordinary cement is preferable. 
 For mixing the cement, a piece of plate-glass about five inches 
 long and three inches wide as a slab and a small spatula are 
 most suitable. The surface of tlie slab mu^t be perfectly clean. 
 The acid and powder should first be separately placed on the 
 glass, the amount of powder being fully ec^ual to the requirements 
 of the acid. Should it be found during the mixing that the pro- 
 [»ortion of powder is too great, the surplus should be instantly 
 thrown off the slab and the mixing, which must l)e rapid and 
 thorough, continued; the consistence should be that of thick 
 cream. If the slab is placed on a towel which has been saturated 
 with ice-water, the cold will retard the setting. 
 
 Fig. 271. 
 
 The parts to be crowned should be previously syringed with 
 water, then protected by a napkin, bathed with alcohol applied 
 by cotton with tweezers, and wiped with bibulous paper. Each 
 cap or crown, which should have been thoroughly dried, is first 
 tilled with enough cement to insure a slight surplus. A small 
 portion is then put in each root-canal or hollow part of a 
 natural crown present, and tlie artificial crown or bridge im- 
 mediately adjusted in position. In many cases it is best to 
 quickly remove the napkin and occlude the teeth to insure the 
 occlusion, and then open the mouth and replace the napkin. The 
 crown or bridge should be held under a slight pressure until 
 the cement sets. For this purpose a piece of wood notched on 
 the end or an adjuster (Fig, 271) can be used. 
 
 AVhen the cement has set perfectly hard, the surplus around 
 the edges should be removed. In collar or shell crowns 
 the edges of the gold of the collar or shell should be given 
 a final burnishing. AVet floss silk or dental fiber, charged 
 with pumice, should be passed between and around the teeth to 
 remove every particle of the superfluous cement, and finally the 
 parts should be syringed with tepid water. 
 
 9 
 
130 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 The patient sLould be requested to call in a few days, so that 
 an examination may be made to see if any particles of the 
 cement were overlooked. Cleansing gently at this time facili- 
 tates the healing of the gum around the collar or neck. Care 
 in these little details tends to prevent that inflamed appearance 
 and recession of the gum often seen around crowns, and also 
 insures a satisfactory result to the patient and commendation to 
 the dentist. 
 
 Previous to insertion the posts of crowns should be slightly 
 barbed. In all-gold cap crowns a vent for the escape of air and 
 surplus cement is usually made in the form of a small hole in 
 the deepest fissure of the grinding-surface. When the cement 
 is hard the hole must in all cases be closed with a gold or amal- 
 gam filling. 
 
 When gutta-percha is used for cementing, the cavity in the root 
 and crown having been moistened with chloroform and then 
 dried and heated by a hot-air syringe, a portion of the gutta- 
 percha is inserted and caused to adhere to the sides. The post 
 and the crown are then heated, the proper quantity of the gutta- 
 percha attached, and the crown inserted. When the gutta-percha 
 is cold, the surplus is removed with a sharp instrument, and 
 the edges smoothed by drawing back and forth against them 
 some twisted fibers of cotton saturated with chloroform. In some 
 cases the post can be fastened with oxyphosphate and the end of 
 the root and artificial crown joined with gutta-percha. The order 
 of the use of these materials can be reversed where it may be 
 desirable at some future time to easily remove the crown. 
 Bridge-work can be conveniently attached temporarily with gutta- 
 percha. In this event a quantity barely sufficient to fasten the 
 caps should be used. Gutta-percha does not possess sufi&cient 
 rigidity for general use in bridge-work. 
 
PART III 
 BRIDGE-WORK. 
 
BRIDGE-WORK. 
 
 The artificial replacement of the loss of a portion of the teeth 
 by bridging the vacant spaces with substitutes, supported in posi- 
 tion by means of their attachment to adjoining or intervening- 
 natural teeth, is, as we have seen in the introduction, of antique 
 origin, having been practiced long before plates came into use. 
 
 Originally, the application and mechanical construction of 
 Fig. 272. Fig. 273. 
 
 
 such dentures was of a most primitive character ; and as the 
 attachments were simply ligatures or clasps of gold, the teeth 
 were more ornamental than useful. Figs. 272, 273, and 274 
 illustrate the anti(|ue methods.^ 
 
 Dentures constructed on the 1-10.2/4. 
 
 bridging plan by various meth- 
 ods have been occasionally em- 
 ployed from the earliest days of 
 modern dentistry, though until 
 quite recently the system has 
 not obtained general recognition nor been extensively practiced. 
 
 Dental literature presents bridging operations as described by 
 
 ^See Independent Practitioner, vols, vi and vii, " Evidences of Prehistoric Den- 
 tistry," by J. G. Van Marter, D.D.S., Rome, Italy. Figs. 272, 273, 274 are copies 
 
 of the illustrations. 
 
 183 
 
134 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 J. B. Gariot in 1805, C. F. Delabarre in 1820, Dr. S. S. Fitch in 
 1829, and Dr. W. H. Dwinellc in 1856. Fi^-s. 275 and 276 
 are copies of illustrations in Dr. Fitch's work, published in 
 New York in 1829. In 1871 the bridging process or bridge 
 principle was again brought to notice by a patent applied for in 
 England by Dr. B. J. Bing, of Paris, for an improved means of 
 supporting and securing a bridge by anchoring with cement or 
 fillings clasps or bars extending from it into holes formed in the 
 adjoining teeth (Fig. 277). The system was also practiced in 
 operations by the late Dr. M. H. Webb, and is described in his 
 " iSTotes on Operative Dentistry." 
 
 The facilities aflbrded by the artificial crown-work now in 
 vogue for supporting and securing bridge-dentures have caused 
 
 Fig. 275. Fig. 276. Fig. 277. 
 
 C C Ct O^ (Z o o 
 
 a revival of the system in an improved form, termed " Bridge- 
 Work," in which artificial crowns cemented to natural teeth or 
 roots are employed as abutments to support artificial teeth which 
 span or bridge the spaces between them. These bridges are so 
 devised, in the best methods, that while supplying the patient with 
 the means of masticating his food the cleanliness of the denture is 
 also provided for. 
 
 Ordinarily, bridge-work is immovably cemented in position. 
 The claims set up in its favor are as follows : 
 
 First. The perfect replacement of lost teeth by artificial ones, 
 and without the use of a plate. 
 
 Second. The absence of any mechanical contrivance to inter- 
 fere with the tongue in articulation. 
 
 Third. The functions of the sense of taste are more perfectly 
 
BRIDGE-WORK. 135 
 
 performed, and a healthy condition of the tissues preserved, 
 because the gums and palate are not covered over with a plate. 
 
 Fourth. The solidity and immovability of the denture at all 
 times, both in speech and mastication. 
 
 Fifth. Its special adaptation to the replacement of single 
 teeth, or of a small number, where bridge-work is usually 
 superior to any other device. 
 
 Sixth. AVhile all operations performed for the restoration of 
 lost teeth, like other remedial operations, are temporary rather 
 than permanent in their results, bridge-work as regards per- 
 manency takes equal rank with any other operative procedure. 
 
 The following, on the other hand, are the objections raised 
 against bridge-work: 
 
 First. It fails to restore the contour of the soft tissues above 
 the bridge, as artificial gums cannot properly be used in this style 
 of work. 
 
 Second. The slots beveled under the artificial teeth, called 
 self-cleansing spaces, fill with particles of food. 
 
 Third. The speech of the Avearer is often afitected by these 
 self-cleansing slots under the front teeth. 
 
 Fourth. If an extensive bridge is made of gold, being im- 
 movable, it is impossible to keep it perfectly clean, as the metal 
 will gradually tarnish in parts out of reach of the brush, and 
 will gather ofi:ensive matter on its surface and in its interstices. 
 
 Fifth. In cases where it becomes necessary to temporarily 
 remove the bridge for the purpose of repair, or because of dis- 
 ease in the teeth which support it, the operation is diflicult and 
 the bridge is usually injured so as to unfit it for re-insertion. 
 
 Sixth. The teeth which support the bridge are required to 
 bear more force and pressure than nature intended, — where the 
 piece is large many times more, — and, the bridge being perma- 
 nenth' attached, at no time can an}' rest be given the abutments 
 or the contiguous parts by its temporary removal. Thus in a 
 
136 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 piece of bridge-work consisting of fourteen teeth supported by 
 four natural ones, each one of the natural teeth may have to 
 bear more than three times the strain in supporting, and the 
 force in masticating, that was intended. The ultimate result is 
 evident to any one who is experienced in dental practice; and 
 unless the anatomical conditions are most favorable, the useful- 
 ness and durability of such work is decidedly limited in character, 
 considering the time, trouble, and great expense attending it. 
 
 Such are the objections M-hich have been put forth against 
 bridge-work ; and yet, whatever may be urged against it, its 
 advantages have won Irom a nuijority of the profession, includ- 
 ing many accepted authorities, an enthusiastic, almost a sen- 
 sational, indorsement; some practitioners even going so far as 
 to proclaim it the only true method for the insertion of artificial 
 teeth. 
 
 Judged impartially, bridge-work has many advantages when 
 practiced by experts who properly construct and apply it. 
 Without doubt it has been abused. Bridges have been inserted 
 where the support was insufficient, or the construction was wrong 
 in principle or faulty from lack of skill. More than this : bridge- 
 work has been passing through the experimental period, when 
 failures are apt to appear more prominently than successes. 
 The chronicles of dental literature, however, in this respect offer 
 only a repetition of the historical difficulties that attend all new 
 departures in the arts. 
 
C II A P T E H I. 
 
 CONSTRUCTION OF BRIDGE-WORK. 
 
 To the skilled mechanical dentist, well versed in metal- and 
 crown-work, bridge-work does not present extreme difficulty. 
 The foundations or abutments — that is, the teeth or roots on 
 which the bridge will rest — are first to be considered, due respect 
 being paid to the mechanical principles controlling the leverage 
 and the force of occlusion in mastication. The amount of strain 
 that can be borne by the different teeth, individually and collect- 
 ively, according to their position and condition of health, should 
 be carefully calculated. 
 
 As a rule, the force exerted upon the incisors in occlusion will 
 be directed outward on the upper, and inward on the lower 
 teeth, and its tendency when they support a bridge will be to 
 gradually push them out of line in each direction. When the 
 incisors are replaced by a bridge, the tendency of the force of 
 occlusion is toward a similar result. On the bicuspids and 
 molars the force is direct. The rules which govern the number 
 and position of the teeth or roots that are required or should be 
 used as foundations for bridges, in practice are as follows : 
 
 One central root will support two centrals, and if spurs or 
 l>ars from the sides of the bridge rest upon or are anchored in 
 the adjoining teeth, a lateral in addition. 
 
 Two central roots will support the four incisors, spurs or bars 
 resting on or anchored in the cuspids to be used additionally, if 
 the case requires them. 
 
 The cuspid roots, alone oi* with the aid of a central root, will 
 support the six anterior teeth. 
 
 One molar or bicuspid on one side, and a bicuspid or molar 
 on the other, with one or two roots in an intermediate position, 
 will support a bridge between them. 
 
 One right and one left molar, with the assistance of the two 
 cuspids, will suppoi't a bridge comprising the entire arch. 
 
 137 
 
138 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 A bridge on one side of the mouth can be supported by two 
 or three teeth or roots on that side. The cuspids always afford 
 the most reliable support. 
 
 In general, the application of these principles will cover the 
 subject of foundations, the operator being governed by the exact 
 condition of individual cases. In a bridge of the six anterior 
 teeth on the two cuspids, when the articulation of the antagon- 
 izing teeth is close and deep, the strain should be relieved by an 
 additional attachment of the bridge to the teeth posterior to the 
 cuspids. 
 
 Fig. 278. 
 
 The preparation of teeth or roots to support a bridge is the 
 same as for ordinary crowms, except that the trimming of 
 the sides and the drilling of the root-canals of the various 
 anchorages should be, as far as possible, in parallel lines, so that 
 the collars and posts of the crowns shall move readily to their 
 places in the adjustment of the finished l;)ridge. 
 
 Teeth or roots which are to be crowned with all-gold cap 
 crowns are crowned by some one of the methods described. 
 Those on which porcelain fronts are to be used are merely 
 capped, the posts being soldered and allowed to project a short 
 distance below the caps. 
 
 The case represented in Fig. 278 will be used to illustrate the 
 construction of a piece of bridge-work in all its details. The 
 
CONSTRUCTION OF BRIDGE-WORK. 
 
 139 
 
 abutments, or supports, consist of the right second molar capped 
 with an all-gold crown, constructed in sections by first forming 
 the collar and then soldering on the cap (see page 89), the two 
 cuspid roots capped for collar crowns with porcelain fronts (see 
 page 84), and the left first molar, which will aftbrd anchorage 
 to a bar on that side of the bridge (Fig. 279). A slot, dovetail 
 in form, is usually cut well into the body, but not to an extent 
 that will endanger the pulp of the last-named crown (Fig. 280). 
 If the tooth is not decayed, it can be first opened up with a 
 rubl)er and corundum disk. The shaping of the slot is best 
 
 Fig. 279. 
 
 Fig. 280. 
 
 accomplished with fissure-burs. With the crowns and caps in 
 position, an impression and articulation of the case are then 
 taken with plaster slightl}- colored with carmine. The plaster 
 is mixed moderately thick and, with the aid of a spoon, placed 
 around in the mouth on the crowns, caps, and parts to be 
 included in the bridge, and the antagonizing teeth occluded 
 tightly and so held until the plaster sets. The mouth is then 
 opened and tlie plaster carefully removed, the pieces being 
 adjusted together should it break. The crowns and caps (the 
 latter held more firmly by the protruding ends of the ]>ins) are 
 removed in it. The plaster is then varnished, and, on the side 
 containing the crowns, a model is run, composed of e([ual parts 
 of calcined marble-dust and plaster, to which is added a little 
 
140 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 sulphate of potassium, — less than the proportion of salt generally 
 used, — which causes the mixture to set hard quickly. AVhen the 
 model has set, it is mounted with plaster on an articulator, and 
 the other side giving the articulation made at the same time. 
 
 Fig. 281. 
 
 Fig. 282. 
 
 51 M 
 
 /) 
 
 When the impression plaster is removed (an operation which is 
 greatly facilitated by its having been colored with carmine), a 
 correct model and articulation of the case will be found, with 
 the crowns and caps in exact position as in the mouth (Fig. 281). 
 
 Another method is to iirst take 
 the impression in an impression- 
 tray, and then tlie articulation in 
 wax, and make a model and ar- 
 ticulation from them in the usual 
 manner. 
 
 The pins protruding from the 
 caps on the model are next cut 
 off. Teeth are selected, — ordi- 
 nary plate teeth for the incisoi's and 
 cuspids, and partial teeth, repre- 
 senting the front section of the 
 tooth and styled porcelain facings, 
 which were specially designed for crown- and bridge-work, for 
 the bicuspids and molars (Fig. 282). Cuspids are sometimes 
 used to form the fronts for bicuspids. The teeth are ground 
 and fitted to the model and articulation, so that the labial 
 
 \j 
 
 V 
 
 95 
 
 - iB*' ""ijii^i.-^ 
 
CONSTRUCTION OF BRIDGE-WORK. 
 
 141 
 
 upper edge of the teeth shall press lightly on the gum. Those 
 which are intended to form the fronts of the caps on the cuspid 
 roots should be adjusted in the ordinary manner for single 
 crowns. To determine the proper positions of the teeth for 
 producing the best appearance, they can be adjusted in the mouth 
 on wax, without the gold crowns or caps of the supports. 
 The correct position of the teeth on the model having been 
 obtained, investing material, composed of one part plaster to 
 two of calcined marble-dust, is placed on the outside of the 
 model on the labial aspect of the teeth, merely sufficient in 
 
 Fig. 288. 
 C A 
 
 A iinil B. central incisor and bicuspid ready for metallic l^ackinpr. C. is a central backed. 
 D, D, D, porcelain fronts as they appear on insertion after the process of Ijacking, capping, and 
 
 soldering. 
 
 quantity to hold them in position, thus 
 The wax is then removed, exposing the 
 permitting their form and position to be 
 The porcelain teeth and fronts, with the 
 for the roots capped, are then removed 
 ment, and the base ground from a line 
 below the pins, straight to the labio-cervical 
 "2f-!3). This is to form the self-cleansins2: 
 
 forming a matrix, 
 palatal portion, and 
 studied (Fig. 283). 
 exception of fronts 
 from their invest- 
 on the palatal side 
 edge (A and B,Fig. 
 spaces, if they are 
 
142 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 desired. The incisors are then backed, using either very thin 
 platinum or pure gold (C). The backings are allowed to extend 
 just over the incisive edge as a protection to it, and, if preferred, 
 down on the curve of the self-cleansing space. A more desirable 
 result is secured if the backing extends only to the edge of the 
 self-cleansing space, and the porcelain is polished, as its surface is 
 superior in cleanliness to that of gold. 
 
 The bicuspid and molar porcelain fronts, their tips being 
 ground off (A, Fig. 284), are lined in the same manner. A cap 
 of pure gold or gold lined with platinum, representing the 
 grinding-surface of each tooth, is struck up as described and 
 
 Fig. 284. 
 
 Fig. 285. 
 
 Iplp-B 
 
 jjMiS 
 
 illustrated in ihe construction of gold crowns (see page 92), and 
 the concave portion filled by melting in scraps of 20-carat gold 
 plate. The surface is then ground smooth (B), and closely fitted 
 to the tip of the porcelain front to form the occluding surface 
 in accordance with the articulation of the lower teeth, and the 
 space filled in with wax. This metallic occluding surface is to 
 protect the porcelain. Triangular pieces of gold plate or plat- 
 inum foil (C) arc then cut and fitted to the sides, over which 
 they should extend slightly, and the tooth is invested, leaving 
 the back open, presenting the form of a pocket (Fig. 285). 
 
 The bar intended to be anchored in the slot cut 
 in the molar on the left side, which is made of iridio- 
 platinum wire, about No. 15 standard gauge, with 
 the end shaped as shown in Fig. 286, is fastened 
 with wax to the tooth and cap, and adjusted in the 
 mouth to obtain accuracy of position before soldering. 
 
 All the teeth should be invested at the same time, the inci- 
 sors and porcelain fronts to the cuspid crowns as shown in Fig. 
 287. In the soldering, 20-carat gold plate should be melted into 
 
 Fig. 286. 
 
CON.STRUCTIOX OF BRIDGE-WORK. 
 
 143 
 
 the pockets formed bv the cap and side pieces to fill out to the 
 line at A, Fig. 288, and flowed over the backings of the 
 incisors and cuspid fronts in sufficient quantity to shape them as 
 shown at B, Fig. 289. The teeth forming tlu' bridge between 
 the crowns are called "dummies." After tbe solderine- and 
 
 Fio L'ST. 
 
 removal of the borax with acid, eaeh tooth is then, when it is 
 easily done, very carefully trimme 1 and finislied. 
 
 The teeth are next placed in their relative positions on the 
 model and attached with wax, as shown at D, D, D, Fig. 283. 
 The model is then detached from the articulator, trimmed down 
 
 Fig. 289. 
 
 Fig. 290. 
 
 as much as i)Ossible in size, and additional investing material, 
 composed of two parts marble-dust and one of plaster, applied 
 until alljof the bridge is covered except the space along the 
 backings andjcrowns where they are to be united in the solder- 
 ing (Fig. 290). In the spaces between the backings pieces of 
 
144 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 gold or platinum plate or wire, about one-eighth of an inch long, 
 are placed lengthwise, and the joints are then well soldered with 
 20-carat gold solder. The soldering is hest done on a concave- 
 shaped piece of charcoal with a gas blow-pipe. When the 
 bridge is removed for finishing, the joints of the backings and 
 crowns are finished with corundum-wheels and points and moose- 
 hide points on the engine, and the entire bridge finely polished 
 with whiting carried by a brush-wheel on the lathe. Any little 
 pits that may exist can be filled in with gold foil. The bridge is 
 
 then ready for insertion (Fig. 
 ^'«- 2^^- 291). If the constructive details 
 
 have been properly performed 
 as described, a finished piece 
 of lu'idge-work is the result. 
 
 In constructing bridge-work 
 many prefer, after the porcelain 
 fronts are backed and the caps 
 forming the occluding surfaces 
 of the bicuspids and molars arc 
 properly adjusted on the model, 
 to invest and do the entire sol- 
 dering at once. When this plan 
 is followed, pieces of gold wire should be laid lengthwise in the 
 slots under the gold cap of the porcelain fronts, and the parts 
 filled in and all the sections of the bridge joined together in 
 the soldering. By this method there is less liability of fracturing 
 the porcelain fronts, but the finishing of the bridge is not so 
 easily or so perfectly done. 
 
 In large pieces of work there is some liability to warping, 
 which may be avoided, whichever method of soldering is 
 adopted, by first removing, in proper position, the "dummies" 
 and soldering those of each span together. The spans are then 
 replaced in the matrix and soldered to the abutments. 
 
 Adjustment and Attachment. — The bridge when finished is ad- 
 justed in the mouth, every point carefully examined, and any 
 alterations required are then made. Should the edges of the 
 collars of any of the crowns catch, so as to prevent their being 
 placed in position, a small quantity of articulating paste should 
 
CONSTRUCTION OF BRIDGE- WORK. 
 
 145 
 
 be applied and the point found and trimmed off. If extensive 
 warping has occurred in the soldering, the bridge must be sawed 
 apart in one or two places, adjusted in the mouth, and removed 
 in an impression-tray, using sufiicient investing material (equal 
 
 Fig. 292. 
 
 parts of plaster and marble-dust with the usual quantity of sul- 
 phate of potassium) to cover only the points of the teeth and 
 crowns (Fig. 292). The inner surface of the tray should be 
 oiled. 
 
 The bridge and the investinc; material are then removed 
 together from the impression-tray, and more investing material 
 is added to complete the investment. The cut parts of the 
 bridge are then soldered together. 
 
 When the adjustment of Fig. 293. 
 
 the bridge is accomplished, 
 it can at first be tempora- 
 rily attached with gutta- 
 percha if desired. For its 
 permanent attachment the 
 pins or posts of the crowns 
 are barbed, and the teeth 
 and roots to which crowns 
 have been fitted are then 
 treated the same as single 
 crowns, and the bridge cemented on with a slow-setting oxyphos- 
 phate cement (see page 128). The end of the bar is anchored in 
 
 10 
 
146 ARTIFICIAL CB.OWN- AND BRIDGE-WORK. 
 
 the slot by either a gold or an amalgam filling. Fig. 293 repre- 
 sents the bridge in position. 
 
 Fig. 294. 
 
 Fig. 295. 
 
 Fig. 296. 
 
 / ; 
 
 Fig. 297. 
 
CONSTRUCTION OF BRIDGE-WORK. 
 
 147 
 
 The Consfrifcfi'oit of Small Pieces of Bn<l(i<'-irork\& much simplilied 
 by the following method : Crowns are first made for the teeth or 
 roots that form the abutments and temporarily placed in position. 
 The teeth — " dummies " — which form the span having been 
 ground and backed, are adjusted and cemented with resin and 
 wax in proper position between the crowns. The crowns and 
 dunmiies are then removed together, in an impression-tray filled 
 with investing material. The inside of the tray should be coated 
 
 Fig. 298. 
 
 with a film of wax with the surface serrated. The impression- 
 tra}^ is then heated, and the investment with the crowns and 
 dummies removed; more investing material is then mixed, and 
 the exposed parts of the crowns and teeth covered. The invest- 
 ment, when set, is then cut away sufiiciently to expose the parts 
 that are to be filled in and united together in the process of 
 soldering. Figs. 29-1:, 295, 296, 297, 298 represent cases of Itridge- 
 work constructed in this manner. 
 
CHAPTER II. 
 
 SPECIAL PROCESSES AND APPLIANCES IN BPvIDGE-WORK 
 
 Shoulders on the Anterior Teeth are sometimes desirable, especi- 
 ally on the superior cuspids at the point of occlusion with the 
 lower teeth. A shoulder can be made l)y melting gold plate 
 into the form of a small ball or globule, then flattening it out 
 and soldering it against the backing. 
 
 Another method is to attach with 
 Fig. 299. Fig. 300. ^^^ transversely across the backing 
 
 /Av in proper position a strip of gold 
 plate as shown in Fig. 299, and then 
 flow in gold to the line A, by spe- 
 cially investing or in the soldering of 
 the bridge. 
 
 Solid Gold. Croir/is. — In a close articulation, when the patient 
 prefers strength to appearance, the bicuspids and molars should 
 be made of solid gold. They are constructed by stamping up 
 the cap (A, Fig. 300) representing the grinding-snrface (see 
 page 90), and then adjusting and cementing with wax a piece 
 of plate cut and shaped to form the front and sides (B), which 
 is then invested and filled in witli gold solder, or, if pure gold has 
 been used in the sections of the crown, with 18- or 20-carat plate. 
 Seamless contour crowns can be used for the purpose as 
 follows : The proper crowns having been selected, the gold is 
 trimmed and the crowns adjusted in position on the model. A 
 matrix of plaster is then placed on the labial side, which permits 
 the palatal portion to be studied, the crown removed, and cut 
 away to the form required. They are then removed, invested, 
 and filled in with gold plate. 
 
 A bar-bridge can be made with these by passing an iridio-pla- 
 tinum wire through the crowns l)efore filling in (Fig. 301). 
 148 
 
SPECIAL PROCESSES AND APPLIANCES IN BRIDGE-WORK 149 
 
 A Solid Gold Croini for a Fulpkss Molar ^ supporting the uiid 
 of a l)ar as shown in Fig. 302, is constructed as fohows : The 
 natural crown is ground down, banded, capped, and pivoted as 
 in Fig. 303. The gohl forming the top of the cap is made per- 
 fectly flat and left projecting a little at the sides. A contoured 
 
 Fig. 301. 
 
 Fig. 302. 
 
 Fig. 303. 
 
 crown of pure gold, or gold lined with platinum 
 
 as a precaution against melting, is shortened suf- 
 
 flciently to represent the absent coronal section 
 
 of the tooth, and with a corundum-disk the orifice ""' v-' 
 
 of the anchorage cavity is formed. A shell of thin platinum of 
 
 the size and shape of the anchorage cavity is then inserted and 
 
 cemented with wax on the inside of the crown. The crown is 
 
 then invested and filled with 18-carat gold solder, which should 
 
 bo cut into small pieces, and be placed successively in the 
 
 Fig. 304. 
 
 crown and melted by maintaining a uniform heat with the 
 large flame of a blow-pipe. The base of the crown is next 
 ground level and accurately fitted to the cap and articulated to 
 the antagonizing teeth. It is then clamped in position on the 
 cap, the pivots of which are protected with investing material 
 (Fig. 304), and soldered to the cap, making a perfect joint. This 
 is an easy method for constructing a difficult form of crown. 
 
150 
 
 ARTIFICIAL CROWN- AND BRIDOE-WORK. 
 
 Fig. 305 illustrates a bridge su[)ported by a bar-anchorage in a 
 solid gold crown on the roots of a molar and a shell crown on 
 a cuspid. 
 
 Connecting Bands or Bars for Bii<l<jes, which obviate the removal 
 of crowns of intervening natural teeth between the sections of a 
 projected bridge, are formed by passing a heavy band of oval- 
 
 FiG. 305. 
 
 Fig. 306. 
 
 Fig. 307. 
 
 Fig. 308. 
 
 shaped gold or iridio-platinum wire anjund the intervening 
 teeth, close to but not touching them, and resting lightly on the 
 gums. The application of this device was first illustrated by 
 br. J. L. Williams, Figs. 306, 307, and 308. 
 
 Intervening roots between the abutments of a projected bridge 
 should not be extracted, but treated, filled, and trimmed level 
 with the gum, as the}' can be made to afford some support for 
 
SPECIAL PROCESSES AND APPLIANCES IN BRIDGE-WORK. 151 
 
 the bridge, which may rest upon them. Figs. 309 and 310 rep- 
 resent a case in which the root of the cus[»id on the right side 
 has been so treated and utilized. 
 
 Fig. 300. 
 
 Fig. 310. 
 
 Shell Aiirhnra;/e <>r f'roirn. — The construction of a shell anchor- 
 age for a cuspid and its practical application in supporting a 
 
152 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 bridge cannot be better described tban in the following words of 
 Dr. J. L. Williams : 
 
 "Fig. oil sbows a piece of work made for a case of quite 
 frequent occurrence. It represents tbe restoration of the inferior 
 bicuspids and first molar of the right side. A gold crown is 
 made for the second molar, and the three intervening teeth or 
 * dummies ' are then constructed. For the support of the ante- 
 rior end of the bridge, the method hitherto practiced has been 
 
 Fig. 311. 
 
 to excise the crown of the cuspid and fit a porcelain crown with 
 gold backing to the root, and to this the anterior end of the 
 bridge is soldered. 
 
 " Fig. 312 illustrates a device which obviates the necessity 
 for removing the cuspid crown. A gold l)and is fitted around 
 the cuspid at the front, shown at a. This l)and is allowed to 
 pass a little beneath the margin of the gum, so as to make 
 the smallest possible exhibition of gold. On the lingual aspect 
 
 Fig. 312. 
 
 of the tooth the band is allowed to be nearly the length of the 
 crown. It will be seen that when this l)an(l is fitted as perfectly 
 as possible there must necessaril}^ be quite a vacancy betAveen 
 the upper part of the lingual surface of the tooth and the band. 
 It is important that this portion of the band fits the tooth 
 perfectly, and an accurate adaptation is obtained as follows : 
 A piece of very thin platinum or pure gold, rolled to N"o. 35 
 American gauge, is fitted over that portion of the lingual surfoce 
 
SPECIAL PROCESSES AND APPLIANCES IN BRIDGE-WORK. 153 
 
 of tlie tooth which it is to cover, d, Fig. 312, shows the shape 
 that this little plate usually assumes. " It can be perfectly fitted by 
 the use of a burnisher, and then, with the band in position, a drop 
 of melted resin wax is flowed into the vacant space between the 
 pure gold and the band. It is now removed from the tootli, in- 
 vested, and after melting out the wax solder is flowed into the 
 
 Fig. 31? 
 
 Fig. 814. 
 
 f} 
 
 vacancy, tilling completely the space occupied by the wax. The 
 top of the lingual portion will now be thicker than is necessary, 
 but it can be ground or filed down to the proper thickness. ' We 
 now have a band which fits all portions of the tooth perfectly. 
 The anterior end of the bridge is soldered to this band, and after 
 the work is properly finished it is cemented in phu-e in the usual 
 
 Fig. 315. 
 
 Fig. 316. 
 
 manner. I> and <•, Fig. 312, show side and lingual views of 
 ihis band after the fitting is completed."' 
 
 A Scdinh'ss S/'c/l Anr/uirni/t is formed as follows: From an 
 impression of a natural crown taken in plaster, gutta-percha, or 
 moldine. a die in fusible metal is formed, and from it a counter- 
 die in lead is made. (See " Gold Seamless Cap Crown.") On 
 
154 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 the die a crown is stamped from a seamletsri cap of p^old (Fig. 313). 
 This crown is then fitted on the natural tooth, the labial aspect 
 of which is exposed by the removal of the section of gold cover- 
 ing it (Figs. 314 and 315). A shell for a cuspid can be made 
 from a gold collar as well as a cap. The shell formed in either 
 manner is then filled with investing material, and strengthened 
 by flowing 20-carat solder over the surface. 
 
 This process for cuspids has decided advantages for the easy 
 formation of a perfect-fitting crown or shell for bridge-work. 
 
 A shell crown can be additionally secured by a pin soldered, 
 or a gold filling introduced, when the gold is removed at the 
 labio-cervical part, as shown at A, Fig. 315. 
 
 Fig. 316 illustrates a case of the lower incisors supported by 
 shell crowns on the cuspids. 
 
CHAPTER III. 
 
 EXTENSION BRIDGES. 
 
 This term is applied to bridges which are chiefly supported 
 bv one abutment. In rekition to the anterior teeth, it consists 
 in attaching a dummy to an artificial crown, to replace an 
 adjoining absent tooth. A bridge of this style replacing two or 
 three of the posterior teeth is formed by using two of the teeth 
 
 Fig. 317 
 
 Fig. 318. 
 
 Fig. 8-i(). 
 
 anterior to it as one abutment, and a saddle for the other. A 
 saddle is an oval-shaped piece of gold, of the form of the gum 
 and a little larger than the base of the tooth, ^ilaced under the 
 posteriqi" tooth of the bridge. 
 
 Figs. 317 and 318 represent an extension bridge. A crown 
 on the cuspid, an all-gold crown on the bicuspid, and a saddle, 
 are the abutments. In constructing this bridge, tlie teeth foi-m- 
 ing the abutments were first crowned. The crowns were then 
 adjusted in position, and au impression and ai"ticuh\tion taken in 
 
 165 
 
156 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 plaster, in which the crowns were removed. From this impres- 
 sion a model was made of plaster and marble-dust, and an 
 articulation in plain plaster. On the model, with the crowns in 
 
 Fig. 321. 
 
 Tig. 322. 
 
 position as in the mouth, the bridge was then constructed by the 
 methods described on page 141. The part of the model on 
 
 Fig. 323. 
 
 Fig. 324. 
 
 which the saddle rested was marked, and enough of the surface 
 of the plaster removed to cause the saddle to press tightly 
 
 Ftg. 325. Fig. 326. 
 
 against the soft tissues when the bridge should be completed and 
 inserted in the mouth. 
 
 A .shell crown on a cuspid can be used as an abutment in this 
 
EXTEXSluy BRIDGES. 
 
 157 
 
 style of bridge, instead of excising the natural crown and mount- 
 ing an artificial crown on the root for the ^/urpose (Figs. 319, 
 320). 
 
 Fig. 327. 
 
 Fig. 828. 
 
 Figs. 321, 322, 323, and 324 represent small extension l)ri(lges 
 of frequent construction, and Fig. 325 a pin-shell crown which 
 can he made to support a porcelain front representing a cuspid 
 or hicuspid. 
 
 Fig. 330. 
 
 Figs. 326, 327, and 328 represent an extension hriduv c-on- 
 structed hy Dr. H. A. Parr, of Xew York. The anterior ahut- 
 ment consists of the six front teeth, which have all been crowned 
 
 Fig. 331. 
 
 Fig. 332. 
 
 and Joined together, the pul}is being preserved in the incisors 
 A saddle on each side forms the posterior abutments. 
 
158 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 A Spur S"j)pnrf consists of a flange formed at the end of an 
 extension bridge, aflbrding support by resting on the pahital 
 wall of either an incisor or cuspid, or in the sulcus Ijetween the 
 cusps of a bicuspid or molar. Fig. 329 illustrates a case with a 
 spur resting against a cuspid. In the case represented in Figs. 
 330 and 831 the spur rests in an indentation in an amalgam fill- 
 ing in the molar, and is termed a cantilever bridge. A bridge 
 formed with a spur which is anchored in a filling is practically 
 a one-bar bridge (Fig. 332). 
 
CHAPTER IV. 
 
 DOUBLE BAR-BPvIDGES. 
 
 In this style of bridge the teeth or (huiimies tbrmiiio- it are 
 siip[)()rte(l l)y bars anchored l)y fillings in tlie natural teeth form- 
 ing the alnitnients. Its use is eontined to the insertion of one or 
 two teeth. In the ineisors and cuspids the cavities of anchorage 
 are formed. in the palato-a})[»roximal portion of the teeth con- 
 tiguous to the space to be bridged, aV)out one-third of an inch 
 from the gingival margin (Fig. 333), and having direct access 
 iiito at least one of the cavities through the ai)proximal wall. 
 
 In constructing the bridge the l)ar 
 is first made. Iridio-platinum wire 
 al)0ut N(^. 14 to Xo. 16 U. S. standard 
 gauge is preferal)ly used for the pur- 
 pose. The extremities are formed 
 square or triangular, increasing in size 
 towards each end, and fitted dee}) into 
 the cavities of the teeth which are to 
 support them. The bar is then adjusted 
 and a suitable plate tooth ground and 
 fitted in [)roper position against it. — a 
 
 portion of the labial surface of the bar beiuu- renu)ved to receive it. 
 The tooth is tlien backed with \erv tliin platimini, cemented with 
 wax to the bar, and the tooth and bar removed, invested, and sol- 
 dered. Sufiicient gold sbonld be added to properlv contour the 
 l>art(A, Fig. 333). Gold and amalgam are the only suitable fillings 
 for anchoring the ends of the bar. Amalgam is o])jectiouable onlv 
 when the position of the cavity renders it visible. It can, how- 
 ex'er. when set be partially i'enio\-ed at tlie exjiosed ]iortion and 
 covered with gold. Fastening one end of the bar tem}H)rarilv 
 with (^xyphosphate while the other is being sei-ured. will some- 
 
 159 
 
160 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 times facilitate the operation of anchoring. When gold is the 
 filling-material used, the rubber-dam is first adjusted on the 
 natural teeth and the bridge placed in position over it. 
 
 The practical success of this style of bridge-work depends 
 chiefiy upon the character of its supports and the skillfulness 
 with which it is anchored. 
 
 A Bar-Bridge loith a Detachable Porcelain Front affords access 
 to the cavities of anchorage and admits of replacement of the 
 porcelain in case of fracture. 
 
 A modification of Dr. I. F. Wardwell's method, which is 
 simple in construction and application in comparison with most' 
 forms in use, is as follows : A thick, narrow piece of 18-carat 
 
 Fig. 334. Fig. 335. 
 
 Fig. 336. 
 
 Fig. 337. 
 
 gold plate, at least No. 18 standard gauge, is soldered to the 
 tooth and its two sides undercut with a very thin separating file 
 (Figs. 334, 335). A very thin piece of platinum, covering 
 the whole l)ack of the tooth, is then burnished against it, well 
 into the undercut sides, annealing the platinum several times 
 during the operation. The platinum is then held in a flame 
 wlnle a small quantity of pure gold is flowed over the outer 
 surface and tlien refitted to the l)ack of the tooth, to which it is 
 again burnished. This operation is repeated until the platinum 
 and gold form a moderately light backing which fits perfectly. 
 The platinum surface is then covered with investing material, and 
 on the other side 18- or 20-carat gold plate fiowed until a suitable 
 thickness is obtained. When trimmed into proper shape and 
 attached to the bar, this forms a substantial ]>acking or socket 
 (Fig. 336) in which, when the bar is anchored, the porcelain tooth 
 can be fastened with a little oxyphos})hate cement or gutta- 
 percha (Fig. 337). 
 
 The Low porcelain front consists of a metallic socket into 
 
DOUBLE BAR-BRIDGES. 
 
 161 
 
 wliicli the porcelain facing- fits, being retained by grooves on 
 the sides. The metallic part is soldered in position and the 
 porcelain front then cemented on. (See page 119.) 
 
 Fig. 338 represents a double' bar-l)ridge fornie'd witb an all- 
 gold molar crown. 
 
 Dr. J. G. Morey's method of constructing a double bar-bridge 
 with a remova])le molar or dummy is as follows : 
 
 The bar is formed as seen in Fig. 339. A countersunk molar 
 is ground and shaped as seen [it A and B, Fig. 340. To the base 
 of the molar and up in tlu' slot is shaped and fitted the shell C, 
 
 Fio. 388. 
 
 Fig. 340. 
 
 Fig. 339. 
 
 Fio. 341. 
 
 /RR"^^ 
 
 made of a \'erv thin })iece of gold and })latiuum ^towu metal by 
 first stamping it on a fusible metal die of the base and tben 
 adapting it to the part. A thin piece of clasp-metal (D) is then 
 formed to fit over the liar and in proper position into the slot of 
 tliesliell (0, Fig. 339), to which it is soldered by investing and 
 soldering on the inside of the shell. The shell is then cemented 
 witli oxyphosphate on to the base of tlie molar as seen at A 
 and B, Fig. 339, and is secured to the bar l)y springing together 
 the edges of the metal at C. Fig. 341 illustrates the tooth in 
 ])t)sition. 
 
 11 
 
CHAPTER V. 
 
 EXTENSIVE APPLICATIONS OF CROAYN- AND BEIDGE-WORK. 
 
 The following illustrations of l)ri(lu'e-work by Dr. H. A. Parr, 
 of JSTew York, show to what an extent the system can he applied. 
 
 EiG. 342. 
 
 Pigs. 342, 343, 344, and 345 represent a case in which the 
 
 Fig. 343. 
 
 roots of the two superior centrals, a partially decayed right first 
 molar, and a badly decayed, }inl})less kdt first molar were all that 
 162 
 
APPLICATIONS OF CROWN- AND BRIDGE-WORK. 
 
 163 
 
 remained of the upper natural teetli. On the two central roots 
 were mounted collar crowns, and on tlie two molars all-o-old 
 
 Fig. 344. 
 
 Fig. 345. 
 
 Fig. 346. 
 
 caji crowns. These four crowns actinu" as al>utnient< for the 
 hridgc denture, hore 1)etweeu them, proportionately on t'ach 
 
164 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 side, the force and leverage of occlusion.' The contour of the 
 arch in the region of the cuspids was restored by a skillful 
 
 Ftg. 347. 
 
 and artistic ])lacing of the artificial teeth, which are prominent 
 and lono-. 
 
APPLICATIONS OF CROWN- AND BRIDGE- WORK. 165 
 
 Fig. 350. 
 
 M \ 1 
 
 Fig. 351. 
 
 Fig. 352. 
 
166 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Figs. 346, 847, 348, and 349 represent a ease in whcih two 
 large and firm superior cuspid roots, a right pulpless molar with 
 a saddle — an invention of Dr. Parr's — on the left side support a 
 large bridge. 
 
 Fig. 353. 
 
 In the bridge-work illustrated in Figs. 350, 351, and 352 the 
 crown of a second l)icuspid, a pulpless molar, and the roots of a 
 cuspid and lateral constitute the abutments. 
 
 Fig. 354. 
 
 The following Figs. 353 and 354 illustrate an extensive case 
 of artificial replacement by crowning and bridging operations. 
 Fig. 353 re])resents the case as presented for treatment. The 
 
APPLICATIONS OF CROWX- AND BRIDGE- WORK. 167 
 
 Fig. 355. 
 
 Fig. 356. 
 
168 
 
 ARTIFICIAL CROWN. AND BRIDGE-WORK. 
 
 few remaining superior and inferior natural teeth had no corre- 
 sponding antagonists, which caused the interlocking and abnor- 
 mal condition in regard to occlusion shown. The superior 
 right bicuspid, the left central, and the left cuspid were crowned, 
 
 Fig. 357. 
 
 the bicuspid being shortened and the cuspid lengthened in the 
 operation. The intervening lateral root between the central 
 and cuspid, ha\'ing been treated and filled, was allowed to 
 remain. With the three crowns to serve as abutments the 
 
 Fig. 358. 
 
 intervening spaces were bridged witli artificial teeth, the exten- 
 sion on the left side being supported by a saddle. The spaces 
 between tlic inferior cuspids and molars on l)oth sides were 
 bridged, the bicuspid on the left supporting the bridge, instead 
 
APPLICATIONS OF CROWN- AND BRIDGE-WORK. 169 
 
 of the cuspid, us on the right ; the k'ft cuspid was crowned and 
 the incisive edges of the incisors trimmed even. 
 
 Fig. 354 ilhistrates the case tinislied and shows the complete 
 artificial restoration of the parts. 
 
 •Figs. 355 and 356 represent a case in which crown- andltridge- 
 work has been extensively applied. The occluding surtaces of 
 the teeth were affected with abrasion. Gold crowns with porce- 
 lain fronts were mounted on the incisors and cuspids, the pulps 
 of which Ave re preserved. The posterior teeth were crowned 
 with all-gold crowns. The missing teeth, except those on the 
 inferior left side, were artificially restored with bridge-work. 
 
 In the case illustrated by Figs. 357 and 358, two superior mo- 
 lars and a second bicuspid on the riglit, and a first bicuspid and 
 a saddle under the " dummy " representing the first molar on 
 the left side, form the ainitments. This piece, at the time of 
 writing, had been worn satisfactorily for four years. Prior to 
 the insertion of the bridge-work, the patient had worn artificial 
 teeth on a jilate. 
 
Fig. 359. 
 
 CHAPTER VI. 
 
 KEPAIR OP CROWN- OR BRIDGE-WORK. 
 
 The fracture of a porcelain front to a permanently attached 
 bridge is an annoying accident for both patient and dentist. It 
 is usually attributable to failure to properly protect the incisive 
 edge or occluding surface of the porcelain with metal, a precaution 
 rendered necessary by the rigid character of the resistance 
 offered the antagonizing teeth through the aljutments. In most 
 cases the porcelain can be replaced without the removal of the 
 bridge, but the attachment is not usually so reliable as in the 
 
 original piece. The following is 
 the method usually adopted : The 
 surface of the backing to the por- 
 celain is trimmed level, the plati- 
 num pins drilled out, and the holes 
 slightly countersunk on the palatal 
 side. A tooth similar to the one 
 fractured, with long pins, is ground 
 and fitted to the backing. The 
 pins are then riveted on the palatal 
 side, into the countersunk holes of 
 the backing. The riveting is l)est 
 done with punch forceps having 
 a large punch, the porcelain front 
 being protected by a })iece of lead placed against the labial aspect 
 (Fig. 359). The heads on the pins should then be burnished 
 smooth with a revolving burnisher. 
 
 Bridge-work can be made with replaceable porcelain fronts 
 which can be easily substituted in case of fracture. A descrip- 
 tion of their application will l)e found at page 160. 
 
 If the character of the breakage is such as will not permit its 
 170 
 
REPAIR OF CROWN- OR BRIDGE-WORK. 171 
 
 re[)air in tlie mouth, the l^ndu'e must l)e reuioved for the pur- 
 pose and tlien re-inserted. Under such eireumstanees the advan- 
 taii;es of bridii'e-Avork in a detachahk' form are most evident. 
 
 The results foHowiuo: the repair of single cr()A\'ns in the UKiuth 
 will seldom repay the labor attendiuii' it. 
 
 Removal of ('emenfcd Crowns and Bridges. — When it 1)ecomes 
 necessary to remove an artificial crown, whether inserted singly 
 or as a support for a bridge, incisors or cuspids are detached by 
 grinding the gold or porcelain away at the palatal section over 
 the post, wdiich when exposed is severed, and the attachment of 
 the cement broken up. The collar can also be slit and bent 
 aside if found necessary. In an all-golil cap crown on a posterior 
 tooth a hole drilled in tlie grinding-surface will give access to the 
 cement, a sufficient quantity of which can then be removed to 
 loosen the attachment; or, the collar can be di^'ided and pried 
 up from the root by first making a groove with a small rubber 
 and corundum disk and then cutting the gold with a sharp in- 
 strument. "With care and patienee in the operation, the crowns 
 will not usually be injured beyond repair. 
 
 When gutta-percha is the cement that has been used, a hot 
 instrument can be placed against the metallic part of the erown, 
 or the crown seized with the l)eaks of heated foreeps, the gutta- 
 pei'cha tliereby softened, and the ('ro\\'n remo\-LMl. 
 
CHAPTER VII. 
 
 DETACHABLE AND REMOVABLE BRIDGE-WORK. 
 
 The evident advantages of bridge-work have stimulated tlie 
 inventive genius of dental mechanists to improve the method 
 and form of its construction and to extend its application. 
 With these objects in view, some bridges have been made so as 
 to be easily detachable by the dentist, and others removable by 
 the patients themselves. 
 
 The construction of bridge-work in either of these forms 
 overcomes the chief objections to the system. Large bridges 
 are much more easily made in a detachable or removable form 
 than are the smaller pieces, which present some of the best 
 features of the permanently attached methods. 
 
 The following ingeniously constructed bridges will serve to 
 illustrate some of the more valuable detachable and removable 
 methods. 
 
 DR. WINDER'S SECTIONAL CROWN METHOD. 
 
 This method, an invention of Dr. R. B. Winder, of Balti- 
 more, presents the novel feature of constructing the crowns and 
 forming the abutments in sections, the bridge being attached to 
 
 the detaclial)]e section. 
 
 Fig. 360. 
 
 Fig. 360 illustrates a case of bridge-work made in this manner. 
 The collar section of the artificial crown is capped and cemented 
 on the natural rrown or root, the gold forming the occluding 
 172 
 
DETACHABLE AXD REMOVABLE BRIDGE-WORK. 173 
 
 portion of the crown, when the bridge i^ adjiusted in por^ition, 
 being secured to it witli a screw. The screw may be made to 
 enter tlie body of the erown as is shown by Fig. 361 or it is 
 
 Fig. 361. 
 
 .^ 
 
 1 
 
 Fig. 362. 
 
 Fig. 368. 
 
 Fig. 364. 
 
 sohlered to the cap on the colhir, jiassing through the occluding 
 section of the crown, and secured by nuts 
 on the screws as illustrated by Fig. 362. 
 
 When iueisor or cuspid roots form the 
 abutments, Dr. Winder first forms a cap 
 for the end of the root, to wliieh a tube 
 is attached extending up the root-canal as 
 seen at A, in Fig. 363. On this cap is 
 mounted the crown (B), the post of which 
 fits the tube tightly. To the crown so 
 formed (Fig. 364) the britlge is joined in 
 tlie usual manner. 
 
 In constructing a bridge of this style, 
 the crowns forming the abutments having 
 first been made, are removed from the 
 mouth in a plaster impression and articulation, from which a 
 
174 ARTIFICIAL CROWN- AND BRIDGE WORK. 
 
 model is made, showing the crowns in position. Each section 
 of the bridge between the crowns is then constructed, and the 
 crowns adjusted in the mouth. The bridges are next inserted in 
 position, and cemented with resin and wax to the detachable 
 sections of the crowns. The wdiole is then removed in investing 
 material, in an impression-cup, or by placing the investing material 
 in position on the bridge. After being removed from the mouth 
 more investing material is added and the bridge and crown 
 sections soldered together. Only the detachable sections of the 
 crowns should be in the investment in the operation of soldering. 
 
 AVhen the bridge is finished the root and collar section of 
 each crown is first cemented on in position in the mouth ; the 
 surface of the detachable section of the crown approximating 
 the section fastened to the bridge is then heated and its surface 
 covered with a mere film of gutta-percha. The bridge is then 
 adjusted in position and secured by the screws or nuts. The 
 gutta-percha prevents the secretions invading the interstices 
 between the sections of the crown. 
 
 The incisive edges can be protected and the occluding surfaces 
 of the porcelain capped with gold as in permanently aitached 
 bridge-work, or they can be formed of the porcelain, which 
 lessens the labor of construction, as the bridge is easily detached 
 from the abutments for the purpose of repair. 
 
 A decided advantage possessed by this method of bridge- 
 work over others in practice is the facility it afl:brds for the 
 ready utilization of irregular teeth as abutments, no matter how 
 nmch they converge or diverge, or lean in or out of the line of 
 the arch. 
 
 DR. LITCH'S METHOD. 
 
 Dr. Liteh's method of constructing detaeha])le bridge-work 
 consists in forming a shell anclKn'age over posts permanently 
 fixed on cuspid roots, and anchoring the ends of the bridge with 
 l)ars in slots formed in natural or artificial crowns. 
 
 Figs. 365, 3tJ6, and 367 illustrate a bridge similar to the one 
 illustrate<l in Fig. 291 with this style of attachment applied. 
 The anchorage for the cuspids is constructed as follows: The 
 root is first capped and pivoted as for a collar crown. On tlie 
 palatal portion of the collar is soldered a flange (A, Fig. 368) 
 
DETACHABLE AND REMOVABLE BRIDGE- U'OBK. 
 
 17 b 
 
 made oi' u'olil, Xo. 16 U. S. standard gautce, beveled oft" to the 
 upper edge of the eohar under the free edge of the gum, the 
 object being to give a hirger surface to the top of the cap. On 
 this ca}), \vliieh covers the end of the root, the ancliorage jiost 
 
 Fig. 365. 
 
 Fig. 366. 
 
 Fig. 36' 
 
 Fig. 368. 
 
 B, which is formed of iridio-]»latinum wire, No. 9 U. S. standard 
 gauge, is sohlered, over and l)ack of the pin (C) Avliieh enters 
 the root-canal, so as to allow room for the jioreelain front D. 
 The porcelain front is ground in proper position on this caii. 
 
176 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 backed, attaelied with resin and wax, and removed witli the cap. 
 The cap is next invested in plaster to the edge of the cohar, and 
 a little plaster placed on the labial aspect of the porcelain front 
 in the form of a matrix, so as to allow the porcelain to be 
 removed and replaced, A piece of heavy iridio-platinnm plate 
 (E), No. 16 U. S. standard gauge, is then shaped into the form 
 of a half-ring, with the ends of the plate against the backing of 
 the porcelain front, and of sufficient size to rest on the flanged 
 edge of the cap when completed. On the outside of this half- 
 ring is fitted and soldered a thin strip of gold, F, of No. 28 
 U. S. standard gauge, Avhich will cover the half-ring and extend 
 l)eyond its up;[)er margin, slightly overlapping the flange of the 
 collar (G). This forms a brace or edge on the anchorage cap as 
 it rests on the root-cap. The half-ring is then fitted to the tooth, 
 attached with wax, and removed with the tooth out of the plaster 
 matrix from the root-cap, invested, and securely soldered on the 
 inside to the backing of the tooth. The tooth and half-ring are 
 then adjusted to the root-cap, over the post of which the ring 
 must slide easily (Fig. 369). To this ring the bridge is soldered 
 the same as to a crown. 
 
 When the bridge is inserted, the cap for the root, with 
 the post, is first cemented on with oxyphosphate. After 
 the cement has set, the anchorage ring is filled with more 
 cement and pressed into position upon the cap over the 
 anchorage post. The surface of the cement (H, Fig. 
 368) can ])e protected by a metallic filling. 
 
 This form of attachment permits the bridge to be 
 easily removed by attbrding access to the cement around 
 the pin. The bar ends of the bridge are anchored in 
 the crowns with gold or amalgam fillings, which like- 
 wise are not difficult to remove. 
 
 The anchorage cavity for a bar in a gold crown for 
 use over a tooth with a living pulp is best made by 
 cutting out the gold to the form of the slot required, and inserting 
 in its place a piece of platinum the shape of the walls of the 
 anchorage cavity. The crown is then filled with investing 
 material, and the metal forming the anchorage cavity soldered to 
 the crown at the edges of the cavity. 
 
 Fig. 369. 
 
DETACHABLE AND REMOVABLE BRIDGE- WORK. 
 
 177 
 
 DR. R. W. STARR'S METHODS. 
 
 Dr. K. AValttT StaiT. of Philadc'li»liia, uives tin- following 
 deseri[»ti()iis of his methods in detachahlo bri<lge-\v(»rk : 
 
 " The ease of Mr. W. })resentcd diffieulties of an unnsual 
 cliaraeter, as may be seen \)\ inspecting the illustration. Fig. 370, 
 which renders detailed description unnecessary. 
 
 '■'■ It will l)e observed that the molars and the left second bicus[»id 
 overliang to a degree that woidd make the taking of an accurate 
 
 Fig. 370. 
 
 impression by ordinary methods well-nigh inijxissible. After a 
 careful stndy of tlie case, it was decided that two separate pieces 
 of detachable bridge-work should be attempted, and, as an 
 essential preliminary ste]t, the overhanging sides of the molars 
 and bicuspids were ground with engine corundum-wheels and 
 points until those sides were made much less inclined, when 
 j)laster im]>ressions were taken, first of one lialf, and then of 
 the (^ther half, of the jaw. Gold i-a}) erowns were closely fitted 
 over the niolai's. left second bicuspid, right first bicuspid, and 
 cuspid stump. Gold t-rowns were made to telescope over all the 
 caps, which were then, by means of oxyphosphate cement, 
 fixed firmly on the teeth. Suitable jilate teeth were selected, 
 
 12 
 
178 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 fitted, backed, and liard-waxed in place between the telescoping 
 crowns. After hardening the wax with cold water from a tooth- 
 syringe, the pieces were careftilly removed, invested, and soldered. 
 The two completed bridges were easily replaced on or removed 
 from the supporting capped teeth, and their appearance when 
 detached is correctly shown by the illustration, Fig. 371, which 
 also shows the capped teeth and stumps. The figure likewise 
 shows the results of the novel method employed in crowning 
 
 Fig. 371. 
 
 the incisors. Gold collars were fitted tight on the necks of the 
 incisor stumps, and the new-style porcelain caps adjusted in the 
 collars, and set in the oxyphosphate cement which had been 
 packed into the collars; thus at the same time fastening the 
 collars on the stumps and the caps in the collars, as shown 
 completed in Figs. 371 and 372. 
 
 " Fig. 372 illustrates the finished crowns and bridges, which 
 latter were secured in position by placing a small piece of gutta- 
 percha in each of the telescoping cap crowns, which were then 
 warmed and carefully pressed in place, — the gutta-percha filling 
 
DETACHABLE AND REMOVABLE BRIDGE- WOJRK. 
 
 179 
 
 only tlie spaces between tlie Hat toi)S of the caps of tlic natural 
 teeth and cusped caps of the bridges. 
 
 "Whenever, for repair or for any other purpose, it shall be- 
 come desirable to remove one of the bridges, that may readily 
 be done by applying a hot instrument or hot air to the caps to 
 soften the gutta-percha sufficiently to permit the telescoping 
 bridge to be taken off. 
 
 " A full u})per vulcanite denture was made to replace the old 
 one, which, 1)y iiu[)roper occlusion, had thrown tlie full force of 
 mastication on the anterior teeth of the lower jaw, and produced 
 
 Fig. 372. Fig. 873. 
 
 ' ""iiUUlllllllllllillillllllllllli!. 
 
 the destructive action that resulted in the deplorable loss of 
 tooth-substance shown in Fig. 370."^ 
 
 The next case also presented unusual difficulties. "The forward 
 overhang of the inferior right second molar was so excessive that 
 an impression could hardly be taken, until with corundum-wheels 
 and points the sides of the tooth had been nnide parallel, or 
 rather slightly tapering to form a truncated cone, Avith the neck 
 as a base. The molar was ali\e and sound, but the crown was 
 gone from the pulpless cuspid, which I 8uital)ly shaped by means 
 of my root-trimmers (Fig. 373). 
 
 ^Dental Cos»ws, vol. xxviii, No. 1, page 17. 
 
180 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 " All impression Wt^s then taken, the cast from which is ilhis- 
 trated by Fig. 374. A seamless gold collar was, hy means of a 
 slightly tapering mandrel, made to exactly fit the tapered natural 
 molar, the lower edge of the collar cut to conform to the gin- 
 gival margin ; a cap piece of gold plate soldered to the top edge 
 of the collar, and a hole drilled through the center of the com- 
 pleted cap (A, Fig. 374). Care was taken to so fit and proportion 
 the cap that it would require finally pretty hard driving to send it 
 home on the tooth ; hut first there Avas fitted to the cap a telescojv 
 ing seamless collar, on which was soldered a gold plate, with cusps, 
 
 Fig. 374. 
 
 to form a molar crown as shown in Fig. 374. The molar was 
 then thorougldy dried, slightly i)aiiited Avith Agate cement, and 
 the cap. A, driven hard down with a flat pine stick held u[»on it 
 and struck with a mallet; the hole in the cap enabling me to see 
 when the cap was quite down. The cuspid was then likewise 
 fitted with a seamless gold collar, the top edge of Avhich was 
 given a roof-shape, as seen above the root in Fig. 374. A piece 
 of gold received a corresponding roof-shape, had a short section 
 of gold tubing soldered into it, and was trimmed to the outline 
 of the collar, l)eside which, B, Fig. 374, its form is seen, and to 
 AN'hich it was subsequently soldered, after suitable investment to 
 keep the parts in t>roper place. The root-canal had been pre- 
 
DETACHABLE AND REMOVABLE BRIDGE-WORK. 
 
 181 
 
 viouslv prejiared to receive the tube, which, with its roofed cap, 
 was with stick and mallet driven hard down over the root. A 
 piece of gold wire exactly fitting the tube had a roof-shaped 
 piece of properly-perforated gold plate slipped over it into posi- 
 tion on the root; became fixed in such relation by a drop of 
 melted hard wax ; was removed, invested, soldered, and finished 
 in such shape that, excepting the hollowness, it looked like tlie 
 tube and cap B. 
 
 "The relations of the occluding teeth had, of course, been 
 determined by an articulating model, and by means of it a series 
 of seamless gold collars and cusp-crowns were adjusted on a thin 
 platinum plate fitted on the cast between the cuspid and second 
 molar, and the collars soldered to the plate after investment. 
 
 Fig. 375. 
 
 The truss thus formed received an appropriate finish l)y the 
 rounding and smoothing of its basal borders. A jilain plate 
 cuspid was backed with gold plate and fitted on the roof-plate, to 
 which, after determining its proper occlusion, it was secured by 
 hard wax; removed, invested, and soldered. It was then put 
 into the tube on the I'oot ; the telescoping cai» put over the molar ; 
 the truss put in ]>osition in the mouth, and the whole covered 
 with plaster and marble-dust, contained in a suitabk- sectional 
 impression-tray, which enabled me to hold the mass steadily in 
 place until the mixture was sufiiciently hard to bring away cap 
 and truss and roof-plat^' all in pi-oper ]t(tsition. A second mixture 
 of |)laster and marble-dust, and a suitabk' trimming of the first 
 mixture after all was hard, sutHced for the soldering process that 
 
182 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 376. 
 
 resulted in the denture which, when finished, appeared as shown 
 detached at C, and mounted on the cast in Fig. 375. It went 
 firmly to place in the mouth, and yet was removable in the 
 possible event of accident to the denture, or for readjustment of 
 the cusp-crowns, which latter could easily be done by warming 
 the piece sufiiciently to soften the gutta-percha, replacing the 
 denture on its anchorages, and directing the proper closure of the 
 occluding teeth. 
 
 DR. C. M. RICHMOND'S METHOD. 
 
 " Dr. C. M. "Richmond, of ISaw York City, in making remov- 
 able dentures of the entirely soldered kind, emplo_ys a zinc die 
 made from a cast of the anchor tooth with its cap on. He 
 makes of crown metal (platinum faced with gold) a collar some- 
 what smaller than the tooth-cap, and deep enough to reach from 
 the gum to about a sixteenth of an inch above the cap. He then 
 
 drives the die into the collar so far 
 that the extra sixteenth of an inch 
 can be hammered over and burnished 
 down on the die-end to form a 
 flanged collar. Outside of this, in 
 the same manner, he forms another 
 flanged collar, and then solders the 
 two together, thus obtaining a close- 
 titting, stiff" collar, that will not 
 stretch in l)eing telescoped on and off" the anchorage, and is kept 
 by the flange from being forced too far over the tooth-cap. A 
 denture of this kind is illustrated in Fig. 376, which also shoAVS 
 his post and roof device in another form than that previously 
 described." ^ 
 
 DR. T. S. WATERS'S METHOD. 
 
 Figs. 377 and 378 represent a case of removable bridge-work 
 by Dr. T. S. Waters, of Baltimore, and will illustrate his methods. 
 Tiie natural molar and bicuspid are capped with gold crowns, 
 the molar being double-capped. The outer cap contains two 
 small springs on the inside surface (see outline molar), which 
 firmly retain it by their pressure on the sides of the inner cap. 
 
 ' Dental Cosmos, vol. xxviii, No. 8, page 497. 
 
DETACHABLE AND REMOVABLE BRIDGE-WORK. 
 
 183 
 
 The l)ancl for the bicuspid crown has two shoulders on the inside 
 which fit into o-rooves cut in the mesial and distal sides of the 
 
 Fig. 3i 
 
 n ffl 
 
 Fig. 378. 
 
 gold forming the crown. Fig. 378 represents the lu'idge in 
 position. 
 
 DR. PARR'S METHODS. 
 
 Detarhahle.—F'ig. 379 illustrates a method of this style. The 
 bridge is sup})()rted between the abutments, which lean towards 
 
 Fig. 379. 
 
 each other |)()st('ri(>rly and nnt<.'riorly owr thi' spare' to l)c' bridgL'd, 
 as shown on the original niode'l. Fig. 380, by two shoulders on 
 the crowns which sli<lc into groows^jformed in the dummies (Fig. 
 381). These supporting shoulders and .><lots are made by sha]iing 
 
184 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 two pieces of plate to the form shown in Fig. 382, so that one shall 
 telescope the other. The inner one is then invested on the out- 
 side surface and filled in with gold plate. The outer piece is 
 then filled inside with investing material, and gold plate is flowed 
 over the outer surface. The shoulders are first soldered to the 
 crowns, and afterward the slots are adjusted to them and soldered 
 in position in the bridge. 
 
 Fig. 380. 
 
 Fig. 381. 
 
 Removable Sectional Bj-idf/e. — In this style the croAvns forming 
 the abutments are permanently cemented in position, each section 
 of the bridge l)etween them being removable. The case illus- 
 trated in Fig. 383 will serve as a type to give the constructive 
 details. The cuspid and molar crowns are first formed in the 
 usual manner. A model from an impression is then made on 
 
 Fig. 383. 
 
 which the crowns will be in the same position as in the mouth. 
 A gold and platinum bar (A, Fig. 384) is then formed between 
 the cuspid and molar. The end for the cuspid is rounded, and 
 that for the molar flattened. 'I'his last may be done by hammer- 
 ing the wire flat or by soldering a piece of clas]) plate trans- 
 versely to it. The two ends of the bar are then fitted in tubes (^f 
 
DETACHABLE AND REMOVABLE BRIDGE- WORK. 
 
 185 
 
 Fig. 384. 
 
 |ilatininii (B, B), and the tubes are soldered to the sides of tlie 
 
 cuspid and molar crowns (A, A, Fig. 383). If jiret'erred, the slot 
 
 on the side of the m(dar crown can be made with a piece of 
 
 platinum adapted over the flat piece of gold forming the end of 
 
 the bar and then soldering the platinum to the side of the crown. 
 
 At this point the crowns and bar should 
 
 be adjusted in the mouth, as well as 
 
 on the model, to insure accuracy. To 
 
 this l)ar the teeth constituting the bridge 
 
 are fitted in their respective positions 
 
 and soldered. Bending either end of 
 
 the bar slightly (B, B, Fig. 383) or sawing a slit in the cuspid 
 
 end of it (Fig. 391), afford the means of holding the bridge 
 
 firmly in position, Avhile it may be removed and reinserted at the 
 
 option of its wearer. Fig. 385 shows the inserted bridge. 
 
 Fig. 386 shows another method of forming a socket attach- 
 ment. In the figure, the socket section of the attachment is 
 seen projecting from the side of the molar crown. The other 
 
 Fig. 385. 
 
 Fig. 386. 
 
 section I'onsists of a cai) liaviiio- a si)rinii' fiancee. The fian^'e 
 enters the socket, AX'hich the cap incloses on the top and sides. 
 The spring is made by cutting tlie part of the flange marked A 
 crosswise and d<nvn wards as marked by the dotted line, and 
 bending it a little to one side. The gold caps forming the 
 occluding surface of the bridge teeth or "• dummies " are adjusted 
 over and soldered to the cap section of the attachment. 
 
 In a bridge of this style of the anterior teeth only, — where 
 the abutments form tlu' extremities of the }iiece, — the ends should 
 be attaclied to the mesial sides of the crowns forming the sup- 
 ports; but when it also carries teeth i)Osterior to the abutment, 
 
186 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 387. 
 
 Fig. 3^8. 
 
 the attachment shouhl be made on the distal t^ide, the Ijar wup- 
 ].iorting the anterior teeth restino- in a slot formed on the jjalatal 
 side of the abutment (Fig. 387). A shell crown on a cuspid can 
 be utilized as a support for this form of attachment. 
 
 Fig. 388 illustrates a removable cuspid crown which can be 
 used in removable bridge-work. It is constructed as follows : 
 The end of the root is first capped. A porcelain cross-pin 
 tootli, tlie pins of which are set well apart, is then ground and 
 adjusted in position, cemented with wax to the cap, and both 
 removed. Enough ;[;ilaster to form a matrix is placed on the 
 labial aspect of the porcelain and 
 collar to hold them in relative posi- 
 tion when the wax is removed. A 
 fl-^^f po st iait hen formed on the root- 
 c|p, cxWimng from the labial edge 
 forwjMU^etween the pins of the tooth, 
 tlie porcelain of which, between the 
 pins, should l)e slightly cut out to 
 receive it. To this is soldered the piece A which is 
 to act as a spring. The post is formed of plate ISTo. 
 18 U. S. standard gauge, and the s}»ring of clasp gold 
 No. 26. The post is soldered to the cap from the 
 opposite side to the spring l)y investing without the 
 tooth. The tcjoth is then lined with very thin plati- 
 num and with the aid of the matrix is adjusted in posi- 
 tion on the cap, and a thin piece of platinum plate is 
 slit at the edges and adapted over the post, cap, and edge of the 
 collar, witli its inner edge meeting the backing of the tooth. 
 The platinum plate is then cemented with wax to the l)acking 
 on the tooth, removed with it from the cap and post, and in- 
 vested, the slot for the post being carefully filled with the invest- 
 ing material. Gold plate is then flowed over the plate and 
 backing so as to consolidate the parts in one piece. 
 
 This crown when finished will fit on to the cap and post, the 
 spring of which can l)e bent to securely retain it. The line of 
 the post on the cap as it fits in the slot in the croAvn should ])e 
 snch as will favor the insertion and removal of the bridge. 
 
CHAPTER VIII. 
 
 REMOVABLE PLATE BRIDGES. 
 
 In tliis stvk' of britlii-e a plate is used to span the space 
 and support the artificial teeth between the abutments. A prime 
 recjuisite of rcm(M'al)le plate brido-es is that the posts and collars 
 or any form of attachments used shall move evenly on and off 
 the su])itortinii- roots or crowns in their adjustment and removal. 
 To secure this, the post-cavities and crowns should be sha]>ed 
 and the gold crowns formed so 
 
 that tlie lines of the center of ^^*^- ''^^■ 
 
 the cavities and of the sides of 
 the gold crowns shall be as 
 nearly as ])ossib]e parallel. To 
 facilitate tlie ojteration, })osts of 
 wood or metal should be first 
 accui'ately but loosely inserted in 
 the root-canals, protrudinu' a 
 ([uarter of an inch, and an im- 
 pression taken. On the model 
 made from this impression the 
 ])osts will l)c found in position 
 as in the moutli. The ])laster 
 crowns are thcu trimmed to the required f>rm. Gutta-percha or 
 im[)i'ession com])oun(l, fitted to the model and removed with the 
 posts in position in it, can then be used to guide the operator, 
 and gang*' the preparation of teeth or roots in the mouth. 
 
 The case shown in Fig. 38U will be taken to descril)e the con- 
 structive details of this class of dentures. In the root of the 
 central a tube is inserted, attached to a cap on the end of the 
 root. Over this cap is [)laced an outer cap which has a split 
 spring pivot or post fitting the tube. A narrow plate between 
 
 187 
 
188 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 the teeth connects the outer cap to a clasp which fits around 
 and rests upon the cuspid. 
 
 The 2)rocess of construction is as follows, — the method being 
 similar when applied to larger dentures of this class : The root 
 of the central is first prepared and capped the same as for a collar 
 crown. The cap is best formed of iridio-platinum plate, No. 35 
 U. S, standard gauge (A, Fig. 390). A substantial piece of gold 
 and platinum wire, from No. 16 t(^ No. 18 U. S. standard gauge 
 (the number being regulated by the size of the root), is slit about 
 one-eighth of an incli so as to form a spring-post or pivot. This 
 is easily done l)y placing the wire in a vise and steadily cutting 
 it downward through the center with a saw-edged strip of very 
 thin steel (Fig. 391). This takes only a few minutes, and is 
 preferable to partially jcnning two pieces of half-round wire. 
 
 Fig. 390. 
 
 A 
 
 ^5 
 
 r» 
 
 Fig. 391. 
 
 The wire is then tapped together at the slit, burnished smooth and 
 rounded just at the end (B, Fig, 390). The tube for this pivot is 
 formed by once encircling the pivot with a piece of iridio-i)lati- 
 num plate, No. 32 U. S. standard gauge, the edge of which is 
 beveled and cut to meet the plate even and close (C). The })ivot 
 is then withdrawn, and the seam is touched along its length with 
 the smallest possible quantity of borax. The proper manner to 
 use borax in fine work is to grind it, mixed with water, on a slab 
 to a cream-like consistence, and apply on thejioint of a camel's- 
 hair brush. A very small piece oi' pure gold is placed in the 
 seam, and the tube is held in the flame of an alcohol lamp. 
 When a sufficient degree of heat is reached, the gold will flow 
 along the seam and form a joint without obstructing the inside 
 passage for the pivot. The pivot is then inserted, and the tube 
 
REMOVABLE PLATE BRIDGES. 
 
 189 
 
 trimmed (D) and gaiiiivd in a ganu'e-piate'. With a drill just 
 the size of the tube tlie root-canal is enlarged so that the tuhe 
 \\'ill fit in tightly. "^I'liis plan prevents weakening of the root 
 by too great enlargement of the canal. A hole the size of the 
 tube is made through the cap, and they are then adjusted (Fig. 
 392), and the ])ivot l)eing withdrawn, the ca[) and tuhe are re- 
 moved, invested, and soldered (A, Fig. 393). The cuspid, which 
 because of its conical fornuition is one of the most dithcult teeth 
 in the mouth to clasp, is trimmed sutliciently to partially s(pnire 
 its ap[)roximal sides, and the palatal portion is notched slightly 
 
 Fig. 392. 
 
 ■L_i 
 
 (A, Fig. 394), to form a shoulder for the clasp to rest ujton. 
 This notch can be safely made, as the enamel is very dense at 
 the point indicatech 
 
 A gold plate is swaged to till the s[»ace l)et\\een the central 
 root and the cuspid as shown in Fig. 393. The cap and pivot 
 are adjusted on the central I'oot and the plate is then titted in 
 the mouth, pressed tightly in jxtsition against the ii'um, and 
 retained there with a little wax w hicli is cemented to the plate 
 and jU'essed against the cuspid and side of the cap. An im- 
 pression of the [)arts and an articulation are then taken in 
 plaster. The cap, pivot, and ])late being removed in the im- 
 pression, they will be i)resente(l on the model madi' from it in 
 e.Kactly the same position as in the mouth. A second or outer 
 ca]» is then constructed f )r tln' root-cap, the band bcinu- made 
 very narrinv at the approximal and palatal side, and open at 
 
190 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 the labial side, as the porcelain tooth to be attached will serve in its 
 stead (B). The pin is then soldered fast in the onter ca[), and a 
 clasp of clasp gold (C), No. 23 to ISTo. 24 U. S. standard gange, 
 is formed to extend well around the posterior approximal portion 
 of the cnspid. The onter cap having been placed in position on 
 the inner one, the plate extending from the central to the 
 cuspid is cemented to it and to the clasp with wax, removed, 
 invested, and the parts soldered together. Aided by the plaster 
 articulation, teeth are ground and fitted by the model, backed, 
 attached to the plate with wax, aud inserted in the mouth. A 
 piece of platinum foil is then burnished to the form of the 
 notch on the cuspid, the clasp fitted over it and attached with 
 wax, removed with the plate, and soldered to it simultaneously 
 with the teeth. 
 
 When the piece is finished and fitted in the rnoutli, the inner 
 
 Fig. 395. 
 
 cap — the end of the tube having been closed with gutta-percha 
 — is first cemented on the central root. A very small quantity 
 of oxyphosphate is used, and while it is yet soft the plate is 
 adjuvsted in position, and allowed to remain there until the 
 cement has set. The split pivot is sprung open a little and 
 forced to place. With the aid of the clasp around the cuspid, 
 it will be found to perfectly secure the plate. Fig. 395 shows the 
 bridge in position. If the plate bridge is tightly adjusted against 
 the soft tissues, and removed in that position in the impression 
 taken with the caps, it will always be found to fit in a similar 
 manner when the bridge is finished and inserted. Should the 
 clas}> cause decay or abi-asion of the cus})id, the tooth can be 
 excavated to a slight depth under the clasp, and filled with gold. 
 This is Ijest done by making a few retaining-})its, filling them 
 with a hand plugger, and then inserting the main body of the 
 
REMOVABLE PLATE BRIDGES. 
 
 191 
 
 gold hy the Herbst irietliod. Such a filling inserted at any time 
 will prevent injnrv from a clasp, A denture of this style can be 
 made to pass intervening teeth. 
 
 In the artificial rejtlacement of the lower teeth in a ease sueh as 
 is illustrated in Fig. 396, a plate l)ridge possesses many advantages. 
 In the eonstruetion of such a denture, the teeth are first properly 
 shaped. Gold crowns (Fig. 397), the sides of which are as nearly 
 as possible }»arallel the one with the other, are then made and 
 fitted to the bicuspid and molar. On the ero\vns, at the buceal 
 sides, a narrow shoulder (A) is constructed to sustain the collars 
 and bridge in position. In some cases this shoulder is placed on 
 the approxiinal side to better ad\'antage. The crowns are then 
 
 Fig. 396. 
 
 adjusted in the mouth, a small quantity of wax being applied 
 inside of the crowns when necessary to retain them in correct 
 position. A piece of plate is next swaged and fitted between 
 the croAvns and attached with wax as deseribed in the previous 
 case. An impression and articulation of that jiart of the mouth 
 are then taken with plaster and the crowns and [)late removed 
 in it. On the model made from this impression, the crowns 
 and plate will appear in position. Collars reaching from the 
 cervical to the occluding edge are fitted to these crowns. They 
 are made by first forming a collar of ample width of thin 
 platinum, about Xo. 32 to No. 34 IT. S. standard gauge, which 
 is easily adapted to the form of the crown, and on the outside 
 of this fitting a slightly narrower stri}) of gold clasp plate, about 
 No. 30 V. S. standard gauge. The gold and jilatinum are then 
 cemented with wax, removed, invested, and soldered together 
 
192 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 with gold solder. A perfeet-litting and reliable eollar is thus 
 formed (B, Fig. 397). 
 
 The collars, though fitting accurately, should move easily oyer 
 the crowns, as they can l^e readily tightened when the case is 
 finished. If a collar is troublesome to adjust and remoye, cut 
 the side opposite to the one attached to the plate, and spring it 
 open a little. Atter the teeth haye been fitted it can then be 
 ao-ain united when the teeth are being; soldered. This collar and 
 shoulder form a support preferable to a partial or an entire 
 double cap, being less difficult to keep clean. A collar is more 
 easily constructed, and also permits the position of the bridge to 
 
 Fig. 397. 
 
 l)e altered b}' the removal of a little of tlie shoulder or f»f the 
 upper edge of the collar. 
 
 The collars and plate are next cemented with wax, removed, 
 invested, and strongly soldered together (B, B, Fig. 397). The 
 artificial teeth are fitted in proper position on the plate ])y the 
 aid of a plaster articulation, attached with wax, and, if preferred, 
 adjusted in the mouth without the crowns. The bridge is then 
 invested and finished. The attachment of the artificial teeth to 
 the plate can be of either gold or rubber. Whichever is adopted, 
 the first bicuspid is best supported by being soldered to the collar. 
 If iridio-platinum is used in the construction instead of gold 
 plate, and the soldering done Avith pure gold, porcelain l)ody 
 can 1)6 used. When ready to be inserted, the crowns are first 
 adjusted with cement, and then the bi-idge, \\'hich is left in posi- 
 tion until the cement sets. By burnishing the collars they can 
 
REMOVABLE PLATE BRIDGES. 
 
 193 
 
 be made to clasp the crowns as tirmly as desired. Fig. 398 shows 
 the denture in position. 
 
 Fig. 398. 
 
 Figs. 399 and 400 repi^esent an upper removal)le plate lu'idge. 
 In its construction the cuspid roots; were first capped, tubed and 
 
 Fig. 399. 
 
 Fig. 400. 
 
 pivoted, and the molars crowned with shoulders formed on the 
 buceal sides. The i)late intended to connect the abutments was 
 then adjusted in position as has l)een described. An impression 
 was next taken and a model and articulation made. The cuspids 
 
 13 
 
194 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 were then doul)le-ca})ped and collars formed on the molar crowns. 
 The double caps, pivots, collars, and plate were next soldered 
 together. The artificial teeth were attached with vulcanite, the 
 
 gum'section being formed with pink. 
 
 Fig. 401. 
 
 In |the case represented in Fig. 401 the natural teeth were 
 very short. The posterior approximal side of the molar was 
 decayed to such an extent tliat the pulp was nearl}' exposed, and 
 
 Fig. 402. 
 
 consideralde irritation of the investing gum-tissue had been 
 caused l)y the clasp of a plate worn by the patient working 
 
REMOVABLE PLATE BRIDGES. 
 
 195 
 
 upward against it. The patient declined to have a plate made 
 which woidd extend across the palate. Tlic lateral was hardly 
 strong enough to support a permanent bridge. The molar was 
 capped, and a removable ai)pliance constructed with a band 
 
 Fig. 403. 
 
 Fig. 405. 
 
 Fig. 404 rei)rcscnts a case in which a central incisor is re- 
 placed on an extension of the plate, the cuspid being partly 
 encircled by a cla.sp with a shoulder resting on the jtalatal sectioii 
 of the tooth. Fig. 405 shows the denture in position. 
 
196 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 406 represents a case in which a bridge-plate was inserted 
 without crowning either of the abutments. The clasp of a 
 plate which had been Avorn for some years had worked upward 
 and abraded the distal section of the cuspid to such an extent 
 as to expose a large portion of the root and superinduce decay. 
 The cavity was tilled \\'ith gold, and the gingival border, by 
 treatment, brought nearly to its normal position on the tooth. 
 A plate bridge, such as is represented in Figs. 407 and 408, was 
 then constructed. Clasps, with flanges resting on little shoulders 
 
 tbrmed at A, A, Fig. 406, support and retain it. A flange such 
 as was used in this case is Ijest made subsequent to the con- 
 struction of the Y»late and clasps, by burnishing a piece of 
 platinum foil in the mouth to the form of the shoulder and the 
 side of a tooth upon which it is to rest, adjusting the clasp over 
 it, and cementing with v, ax, then removing, investing, and 
 soldering. Wherever the platinum is placed the solder will flow 
 and till all the space between it and the clasp. This gives the 
 exact form of the tooth. 
 
 Fig. 409 shows the denture finished and in position. If the 
 
REMOVABLE PLATE BRIDGES. 197 
 
 teeth are dense in structure, an attachment of metal held in 
 proper position against the lower portion of a crown will l)e 
 worn a long while hefore it causes injury to the parts. Filling, 
 or crowning, if necessarj^, can su])se({uently be resorted to. 
 
 By a correct application of the methods just explained and 
 illustrated, a piece of removahle l)ridge-work of this style can 
 l>e devised for those cases in whieh it is practicahle. / 
 
CHAPTER IX. 
 
 THE LOW BKIDGE. 
 
 Dr. J. E. Low, of Cliicago, is the reputed inventor of bridge- 
 work formed with self-cleansing spaces and supported by means 
 of cemented collars or collar crowns.-^ 
 
 The following is Dr. Low's method of using his step-plug 
 crown (gee page 119) in conjunction with all-gold cap crowns 
 in bridge-work. Fig. 410 shows a case with the prepared 
 molar crowns and cuspid roots. The bridge constructed 
 according to this method is seen in Fig. 411, and adjusted in 
 position in Fig. 412. Figs. 413, 414, 415 illustrate a case of 
 four incisors supported by two step-plug crowns on tlie cuspids. 
 
 Dr. Low gives the following instructions relating to the con- 
 struction of shell crowns or anchorages on cuspids, to support a 
 bridge of the four incisors in a case such as is shown in Fig. 416 : 
 " I first measure the tooth with strips of tin, and make the gold 
 
 'The construction of bridge-work supported by collars or any form of collar 
 crowns cemented on teeth or roots, according to a recent judicial decision, is not 
 at present free to public use. The two claims which reserve the use of these 
 methods to the inventor as specified in the letters patent granted, are as follows : 
 
 "What I now claim as new is: 1. The herein-described method of inserting 
 and supporting artificial teeth, which consists in attaching said artificial teeth to 
 continuous bands fitted and cemented to the adjoining permanent teeth, whereby 
 said artificial teeth are supported by said permanent teeth without dependence 
 upon the gum beneath. 
 
 " 2. An artificial tooth cut away at the back, so as not to present any contact 
 with the gum except along its front lower edge, and supported bj^ rigid attach- 
 ment to one or more adjoining permanent teeth, substantially as and for the 
 purpose set forth." 
 
 A denture between two or more teeth or roots, supported by such means as bars 
 extending from it anchored into teeth or caps or crowns which do not encircle the 
 teeth or roots, with the artificial teeth resting on or pressing into the gums and 
 not formed with what are termed and described as self-clean-ing spaces, and 
 removable bridge-work, are not, in the opinion of experts, included in the mean- 
 ing or specifications of this patent. — G. E. 
 198 
 
THE LO W BRIDGE. 
 
 199 
 
 bands and cut out the outside lower i)ortion of the band before 
 beginning to fit. In fitting, as the band is ])eing driven down, cut 
 away any of the l)and that touches the gum before all touches; 
 never drive the band under the gum, as inflammation will ])rob- 
 
 FiG 410. 
 
 ably follow. 1 mention this, as I have seen many attempts tojget 
 rid of the bands by driving up under the gums and cutting them 
 out on the front, until they are too narrow for strength. The 
 
200 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 bands should l^e heavy and strong, and the patient shoukl under- 
 stand that if he expects to get rid of the annoyance of the plate 
 he must sacrifice his dislike to showing gold. After driving the 
 bands up close to the margin of the gums, as the cuspid teeth 
 are very tapering, the l)ands will have to be taken in at the 
 
 Fig. 413. 
 
 bottom. To do this I slit the band about a third of its length 
 up, then place it on the tooth again, lap it over to bring it to a 
 close fit, and then take it off and solder. Continue taking it in 
 wherever it docs not perfectly fit the tooth, and after a good fit 
 Fig. 414. Fio. 415. 
 
 is obtained proceed with the construction of the bridge by taking 
 an imy)ression aufd articulation. 
 
 " In adjusting the bridge when finished first try it on to see that 
 it fits and that the articulation is all right. Fig. 417 shows the 
 case ready for adjustment. Next dry the teeth upon which the 
 
THE LO W BRIDGE. 
 
 201 
 
 bands are goinii', and then mix your cement. This should be 
 mixed to about the consistence of thick cream. It must be 
 neither too thick nor too thin, or tlie adhesion will not be strong 
 enough to hold. Cover your teeth with cement, and then the 
 
 Fig. 416. 
 
 inside of the bands. Place these on the teeth and carefully 
 mallet up into position. For this purpose 1 use a steel instru- 
 ment with a crease or groove in the end. The teeth must be 
 kept dry after the case is in position until the cement is well set. 
 
 Fig. 417. 
 
 Fig. 418. 
 
 After this is done bevel the edges of the bands and burnish close 
 to the teeth, and if properly done they will resemble gold fill- 
 ings. In Fig. 418 we have the case completed. I always 
 impress upon my patients the necessity of having the case reset 
 
202 
 
 ARTIFICIAL GROWN- AND BRIDGE-WORK. 
 
 immediately should it l)ecome loose, and advise them to have 
 their case examined at least once a year." 
 
 Dr. Low has invented for use in crown- or bridge-work a 
 ready-made metallic socket or shell, into which fits a correspond- 
 ing porcelain front, which can be replaced in case of fracture. 
 
 Fig. 419.. 
 
 Fig. 420. 
 
 Fig. 421. 
 
 Fig. 422. 
 
 Fig. 423. 
 
 Fig. 419 shows a socket shell. Figs. 420 and 421 represent a 
 socket with the porcelain in position. Fig. 422 represents the 
 socket as made for the incisors and cuspids, and Fig. 423 the 
 porcelain in position. 
 
CHAPTER X. 
 
 DR. KNAPP'S METHODS. 
 
 Dr. J. RoLLO Knapp, of New Orleans, has introduced some 
 novel methods in crown- and bridge-work, for etfectiug artistic 
 residts and continuity of structure. 
 
 In crown-work. Dr. Knapp invests for soldering so that the 
 parts to be united and tilled form a miniature mold. Into this 
 mold, at a high heat, with a pointed flame from his blow-pipe, 
 he flows solder, whieh fills the interstices, joins the parts, and 
 assumes the form of the mold. The following is a brief descrip- 
 tion of his methods : 
 
 Fig. 424. 
 
 Fig. 425. 
 
 Fig. 426. 
 
 In constructing a gold collar ci'own with porcelain ti-ont, for 
 an incisor or cuspid, 22-carat The S. S. White Mfg. Co.'s collar 
 gold, No. 28 standard gauge, is used for the collar, whicb is formed 
 by adapting the gold to tlie root by the aid of pliers. Tlie cap to 
 the band is tlien made of i)ure gold, No. 34 gauge, and a gold 
 [)in soldered in position for the root-canal. A plate tooth is then 
 ground in jiroper position, backed with pure gold, and fastened 
 to the cap with wax. On being removed from tlie mouth after 
 proper adjustment, the side and incisive portions of the wax, 
 including the edges of tlu' backing and contiguous portions of 
 the caj), are completely enveloped with pieces of jaire gold No. 
 34 gauge (Figs. 424 and 42.5). The crown is then invested so 
 that when the wax is removed the l)acking on the tooth with tlie 
 
 20:5 
 
204 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 gold on tlie sides shall form a small mold or pocket (Figs. 426 
 and 427). When the investment is heated, the flame of his 
 l)low-pipe is played over its surface until the mass is aglow, 
 when the point of the flame is thrown into the mold by rapid 
 thrusts until the solder melts like wax and fills ever}' part of the 
 mold with liquid gold. This gives an excess of gold which 
 aflibrds ample facilities for contouring in the process of finishing 
 (Figs. 428 and 429). 
 
 Fig. 427. 
 
 Fig. 428. 
 
 Fig. 429. 
 
 Fig. 430. 
 
 In constructing a bicuspid crown with porcelain face, the 
 natural tooth is ground down to the gingival edge and capped 
 similar to a cuspid. A bicuspid porcelain front is then ground 
 and fitted in position (Fig. 430), and the remaining portion of 
 the crown is shaped in wax to the form required. A die of the 
 grin ding-surface is then made in metal, a cap stamped in pure 
 
 Tig. 431. Fig. 432. Fig. 433. Fig. 434. Fig. 435 
 
 gold, No. 34 U. S. standard gauge (Fig. 431), and tlie cusps 
 filled with 20-carat gold solder. This ca[) is next trimmed (Fig, 
 432) so as to fit when placed in pro})er position against the end 
 of the porcelain cusp, for which purpose suflicient wax must be 
 removed. The approximal surfaces are enveloped and the 
 [)alatal portion of the collar protected with pieces of pure gold 
 
DR. KNAPP'S METHODS. 
 
 205 
 
 No. 34 standard u'auii-e, whicli are slit to facilitate their adjust- 
 nient (Fiu'. 433). This leaves the palatal jjortion (»iien when 
 the crown is invested and the wax removed, which last should l)e 
 done with hot water. Fiii'. 484 shows the invested crown ready 
 for soldering, in which operation the parts are tilled in and 
 joined with 20-carat gold solder. The result when finished is a 
 solid gold crown with a porcelain front (Fig. 435). 
 
 All-gold hicuspid and molar crowns are formed bv Dr. Knapp 
 in a similar manner, but as porcelain fronts are not used in 
 these cases, the thin gold plate is placed entirely around the 
 lal)ial aspect of the wax model. In crown-work, after the 
 cap has l)een made, an impression is generally taken and a 
 
 Fig. 43(j. 
 
 Fig. 437. 
 
 A 
 
 plaster model and articulation made to facilitate the subse(iuent 
 construction. 
 
 Dr. Kna])p's method of constructing bridge-work is similar to 
 that in general use except in the investing and the soldering of 
 the parts together, the latter being done with the blow-pii)e in a 
 manner similar to that alxn^e described. 
 
 Figs. 43(3 and 437 illustrate specimens. 
 
 Dr. Knapp's compound blow-pipe (Fig. 438) consists of a 
 miniature blow-pipe in which the ordinary illuminating gas 
 (carburetted hydrogen or coal-gas) flame is combined with a 
 current of nitrous oxide from a cylinder of the condensed gas. 
 The combination of these ii'ases in combustion forms essentially 
 
206 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 a carbo-oxy hydrogen flame/ By means of a yoke and set- 
 screw, the valve of the cylinder is connected with the tubes and 
 valves of the blow-pipe, so that the proportions of the mixture 
 
 Fig. 438. 
 
 * The ordinary compound oxyhydrogen blow-pipe flame is produced by 
 2 volumes of hydrogen; 1 volume of oxygen. 
 
 Carburetted hydrogen consists of 
 
 2 volumes of hydrogen ; 1 volume of carbon. 
 
 And nitrous oxide of 
 
 2 volumes of hydrogen ; 1 volume of oxygen. 
 
 Consequently Knapp's blow-pipe flame is produced by a mechanical mixture of 
 2 volumes of hydrogen ; 1 volume of oxygen ; 1 volume of carbon. 
 
DR. KNAPP'S METHODS. 207 
 
 of nitrous oxide and the illuminating gases are under }iertect 
 control. The tiaiue-jet can be diminished to half an inch in 
 length, and at that size will melt a small piece of gold plate. 
 
 This blow-[)ipe is useful for many purposes in the laboratory of 
 the present time, especially in forming solid gold backings to 
 dummies for bridge-work, strengthening seamless gold crowns, 
 and forming solid gold crowns. 
 
 Dr. Knapp has exhibited to the profession some very fine 
 specimens of erown- and bridge-work, and presented much that 
 is novel and interesting, as well as encouraging to the artistic 
 element of prosthetic dentistry. The real value of processes or 
 methods, however, depends on their practicability. Therefore, 
 in contemplating that which is novel and beautiful in connection 
 with dental art, we must be governed by this fact in estimating 
 its value. Judged from this stand-point, Knapp's special methods, 
 while admitting of the highest artistic results, embrace processes 
 which, on account of their intricacy, are not likely to be adopted 
 in general practice. 
 
CHAPTER XL 
 
 DR. MELOTTE'S METHOD. 
 
 Dr. G. W. Melotte, of Ithaca, N, Y., describes the construc- 
 tion of a bridge supported by a gold crown, and a shell or par- 
 tial gold crown, and the use of his invention, "moldine," in con- 
 nection with fusible metal in crown- and bridge-work as follows : ^ 
 
 " Fig. 439 illustrates a case for the supply of a lateral and a 
 
 bicuspid. In this instance the cuspid could be cut off, and the 
 
 root collared and capped in combination with a pin entering the 
 
 enlarged root-canal; but as there maybe grounds for objection 
 
 to cuttino; off sound teeth, I ob- 
 FiG. 439. . , * . , '. 
 
 Q VI ate the necessity by cuttmg a 
 
 iiPfjL shoulder on the lingual portion 
 I I I I ox 
 
 _, _~^--/ _J of the cuspid, and suitably 
 
 •'^^— ^ ^ shaping its sides to permit a close 
 
 fitting of the collar just under 
 the free margin of the gum. A narrow strip of pure pattern 
 tin, bent tight around the tooth-neck, and cut through with a 
 knife at the lap on the labial surface, will serve as a measure for 
 the length of a strip of 22-carat gold plate, IsTo. 29 thick, and as 
 wide as the length of the distal side of the cuspid. The ends of 
 the gold are then squared, and with round-nosed pliers brought 
 evenly together, to be held in flush contact by the soldering- 
 clamp as shown in Fig. 440. The soldered collar, with its joint 
 side inward, is then adjusted on the tooth as accurately as pos- 
 sible, giving slight blows with a mallet until the collar touches 
 the gum, when it should be marked to indicate the necessary 
 trimming to conform it to the gum contour. After it has been 
 thus trimmed, the edges beveled, the labial part swelled with 
 contouring pliers, and the lingual part cut down to about one- 
 
 ^ Dental Cosmos, vol. xxviii, No. 12, page 745. 
 208 
 
DR. MELOTTE'S METHOD. 
 
 209 
 
 tenth of an inch in width, the collar is again driven on, and will 
 appear as seen in Fig. 439. A stump corundum-wheel is then 
 used to grind a shoulder on the lingual surface of the tooth, 
 grinding also the edges of the collar flush with the shoulder. 
 The collar is again removed, and a piece of thin platinum plate, 
 about No. 32, sufficient to cover the lingual surface of the tooth, 
 is caught on the lingual edge of the collar hy the least bit of 
 solder, and all put in place on the cuspid (Fig. 441). The 
 platinum should now be burnished on to the shoulder, and over 
 the tooth and collar to the extent shown by the lines in Fig. 441. 
 
 Fig. 440. 
 
 Fig. 441. Fig. 442 
 
 After trimming to those lines, and careful replacement and 
 burnishing on the tooth, the collar and half-cap are removed, 
 tilled with wet plaster and marble-dust, and the platinum soldered 
 to the gold. It is then placed on the tooth, burnished into all the 
 ine(iualities of the tooth, very carefully removed, invested, and 
 enough solder flowed over the 
 platinum to cover and give it 
 strength. Fig. 442 shows it 
 complete on the cuspid. 
 
 " I have feared that a detailed 
 statement would imply a long 
 and tedious process, but I have 
 often made such collars in less than an hour, and in any case 
 time must be made subservient to exactness of fit and adaptation 
 to the end in view. 
 
 " In the preparation for fitting a collar on the first molar (Fig. 
 439), I should have wedged or otherwise separated it from the 
 second molar, so that a piece of sheet brass might be put in 
 place, as shown by Fig. 443, and an impression taken in plaster, 
 
 14 
 
 ^^C 
 
210 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 whicli if allowed to get hard would bring away the metal. If 
 not, it could be replaced in the plaster. Melted fusible metal, 
 when near the cooling point, is then poured into the impression, 
 and when cold will allow the safe removal of both the plaster 
 and the metal strip. On this metal model a collar can be formed 
 that will accurately fit the molar, as seen in Fig. 439. If the 
 molar has no antagonist, a cap maj' at once be struck up on the 
 model; but if there be an antagonist the cusps of the natural 
 molar should be removed by grinding at points where the 
 occluding tooth will admit of sufficient thickness of the gold 
 cap. An exact copy of the ground cusps can then be made in 
 less than five minutes, by the use of moldine with its acces- 
 sories, and the process is as follows : Make the tooth perfectly 
 dry. Put the collar on it. ISTearh^ fill the cup with moldine, 
 and coat it with soapstone powder. Press the compound on the 
 tooth and collar firmly to al)Out one-fourth the depth of the 
 tooth. Carefully remove the cup ; trim oflf any overhanging 
 material, and place the rubber ring over the cup to about one- 
 half the depth of the ring. Melt the fusible metal and pour it 
 as cool as it will run from the iron ladle. As soon as the metal 
 is hard, remove it with the ring, taking care not to impair the 
 impression, which can be used again if the die is found imperfect 
 or gets injured in use. Place the die and ring in cold water, to 
 remain until quite cooled. While the die is wet and held over a 
 basin of water, pour into the ring fusil )le metal which has been 
 stirred until it begins to granulate, and (juickly immerse all in 
 the water. The die and counter-die should separate readily by 
 tapping them with a hammer, but if they stick others can be 
 quickly made from the same impression by the same method, 
 using more care. With this die and its counter-die, a piece of 
 ISTo. 29 or 30 gold plate is swaged to fit perfectly the cusps and 
 collar, which, when removed, can be held to its place on the cap 
 by the soldering-clamp, using spring pressure enough merely to 
 hold them together for careful soldering with the pointed flame 
 so as not to unsolder the collar. The seamless collars are excel- 
 lent when care is used in selecting the proper size, as directed 
 on the diagram (see page 223). 
 
 " The caps being in place on the cuspid and molar, an impres- 
 
DR. MELOTTE'S METHOD. 211 
 
 sion is taken with plaster; the caps accurately set in the impres- 
 sion, and hard wax melted with a hot spatula around the edges 
 of the caps. The im}>ression is then thoroughly coated with 
 sandarac varnish, after which it is dipped for a moment in water, 
 .and tilled with a wet mixture of one part marble-dust with two 
 parts of plaster; using great care to perfectly fill the caps and 
 molds of the teeth. Wait until this mixture has become quite 
 hard; remove the cup, and Avith a suitable knife chip off the 
 plaster without marring the cast ; secure a good articulating 
 
 Fig. 444. 
 
 impression, and transfer it to the cast to obtain an exact repro- 
 duction of the relative occlusions of all the teeth involved. 
 With such an articulation in hand, and with the means already 
 described for swaging gold or platinum plate to fit the cusps and 
 articulating surfiices of cither the natural or artificial teeth, it 
 should be within the capacity of any competent dentist to com- 
 plete a suitable bridge; although there are practical ])oints that 
 can only be imparted by clinical instruction and actual demon- 
 stration in the mouth. Such a bridge is shown in position by 
 Fiii-. 444." 
 
CHAPTEE XII. 
 
 PAETIAL CAP AND PIN-BRIDGE METHODS. 
 
 Dr. W. F. Litch's processes in this style of work have for 
 special cases many decided advantages, and are thus described 
 by him : ^ 
 
 " Fig. 445 represents a typical case, in which a lateral incisor 
 (crown and root) has been lost, the cuspid and front incisor, fully 
 vitalized, and without approximal carious cavities, remaining in 
 position. 
 
 " To Make a Pin and Plate Bridf/e. — 1. Take in plaster an 
 accurate impression of the cuspid and incisor and the interspace. 
 From this obtain a plaster model of the parts. 
 
 Fig. 445. 
 
 " 2. Make from pure gold, rolled to the thinness of No. 26^ 
 standard gauge, base-})lates, to be carefully adjusted to the palato- 
 approximal surfaces of the cuspid and incisor. These can be 
 made by swaging on dies and counter-dies ol)tained from the 
 model, but more conveniently l)y bending the gold into shape 
 upon the plaster model and pressing and burnishing it into per- 
 fect adaptation upon the natural teeth. 
 
 " 3. Select a plain plate porcelain tooth of suitable length, 
 shape, and shade, and wide enough to fit easily into the inter- 
 space. Let the neck of the tooth rest lightly upon the gum. 
 
 ^Denial Cosmos, vol. xxviii, No. 3. 
 
 212 
 
PARTIAL CAP AND PIN-BRIDGE METHODS. 213 
 
 " 4, With pure gold or i)lutinuiii makc^ a Ijackiug for the })0r- 
 celain tooth. 
 
 " 5. Place the tooth thus prepared and the base-plates already' 
 made upon the east and accurately adjust the approximal edges 
 of the l)ase-plates to the backing of the porcelain tooth in situ 
 upon the cast. 
 
 " 6. When this adjustment is made, cement together the base- 
 plates and backing with a brittle, resinous cement (resin, two 
 parts; wax, one part; or sealing-wax will answer), and l^efore 
 the cement has fully hardened remove from the cast to position 
 in the mouth, perfecting the final adjustment there. By this 
 method much greater accuracy of adaptation is obtained, as the 
 lines of length, width, and contour are too fine to be repro- 
 duced with absolute fidelity in a plaster model. In this part of 
 the process too much care cannot be taken to have each piece of 
 the appliance fitted Avith absolute accuracy to the surface for 
 which it is designed. When this has been accomplished, throw 
 upon the yet more or less plastic cement a stream of ice-cold 
 water from an office syringe ; this renders the cement perfectly 
 brittle and incapaVdc of bending. This done, immediately 
 remove from the mouth and invest in a mixture of equal parts 
 of marble-dust and plaster of Paris. 
 
 " 7. After the investment has firmly set, solder the base- 
 plates to the backing, and the backing to the platinum pins of 
 the porcelain tooth, using as a solder 20-carat gold. Thus 
 joined, the ajipliance will present the appearance shown in Fig. 
 449, — A representing the l)ase-plate for the cus})id; B, the base- 
 plate for the incisor; C, the porcelain tooth with its platinum 
 backing; D, the points of union between the base-plates and 
 backing. At these points the greatest strength is required, and 
 it is important that here a large amount of the solder should be 
 placed. The porcelain tooth being usually thinner than the 
 natural teeth, there is nearly always an angle or depression at 
 the points indicated, in which the thickness of the gold can be 
 considerably increased without interfering with occlusion. 
 
 "■ 8. For the purpose of attaching the denture as thus far con- 
 structed, drill a small cylindrical opening through the palatal 
 surface of the enamel of the cuspid and incisor respectively. 
 
214 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 These openings should usually be placed about as indicated in 
 Fig. 448, at C, D. Sometimes, owing to a close occlusion or to 
 the contour of the tooth, it is desirable that they should be located 
 a trifle nearer the neck of the tooth. Each opening should 
 be well undercut, but must not encroach upon the dentine far 
 enough to endanger the pulp. In size the openings need not 
 be larger than will admit a platinum pin-head, in diameter corre- 
 sponding to E'o. 13, standard gauge, with a shank of ISTo. 18, stand- 
 ard gauge. Into each of these openings must be iitted a platinum 
 pin of the size indicated. The head of each pin must be made 
 thin and perfectly flat b(^th upon its upper and under surtaces. 
 
 " 9. In each of the base-plates make an opening corresponding 
 in position to those in the natural teeth. Pass through these 
 openings and cement in them the free ends of the platinum pins. 
 
 Fig. 446. Pig. 447. 
 
 While the cement is yet plastic, place the denture in position in 
 the mouth, carefully pressing the pin-heads into the openings 
 made for them, and burnishing the base-plates into perfect 
 contact with the palatal surfaces of the teeth; chill the ce- 
 ment, remove and invest as before, and with 20-caratgold solder 
 the pins to the base-plates, flowing upon them and the backing- 
 as much of the solder as may be necessary to give them the 
 desired thickness and rigidity ; the amount admissible largely 
 depending upon the nature of the occlusion ; a central thickness 
 of about No. 21, standard gauge, being all that is really requisite 
 for strength, while the edges can be made much thinner. 
 
 " Fig. 446 represents the appliance without the pin. A is the 
 porcelain tooth and 1)acking; E, the base-plates; C and F, the 
 openings for the pins. 
 
 " Fig. 447 represents the appliance completed with the pins in 
 position. 
 
PARTIAL CAP AXD PIX-IiRIDOEMETHODS. 
 
 215 
 
 "Fig. 448 represents the natural teetli and interspace B, witli 
 openings for retaining-pins, C, D. 
 
 "Fig. 449, already described, represents the appearance pre- 
 sented when the bridge is cemented in position. 
 
 " Jf> Atiarit Ihe Bryhjc. — To attach the bridge the best attaina- 
 ble oxyphospliate cement should be used. It is desirable that it 
 should set slowly. Thoroughly dry the teeth and denture; mix 
 
 the cement to as thick a consistence as is com[)atible with per- 
 fect plasticity. A thick, viscid, semi-fluid mass is what is 
 required. Witli suitable instruments, swiftly l)ut carefully place 
 the cement around the head and sliank of each platinum pin , and 
 also in the openings in the natural teeth. This care is neces- 
 sary in order to exclude all air-bubbles and thoroughly engage 
 the pin-heads in the cement. They furnish ample retaining 
 
 surface, but none to spare. In packing the cement around the 
 pins the under surface of the base-plates should at the same 
 time be covered. 
 
 " The above details being perfected, the denture is at once 
 carried to position, and with l)road-pointed, serrated instruments 
 pressed tirmly into })lace, the excess of cement, if of the proper 
 consistence, freelv oozino:: at all margins." 
 
216 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 ^'•Application to Palpless Teeth. — In the above description the 
 ^itaHty of the pulps of the cuspid and incisor has been assumed ; 
 but, as can readily be understood, the pin and plate bridge can 
 be even more readily and securely placed when one or both 
 pulps are devitalized, for the reason that, the pulp-chamber being 
 empty, the pin-holes in that tooth can l)e made as much larger 
 and deeper as may be deemed desirable, the size of the pin being, 
 of course, correspondingly increased. In a devitalized tooth, 
 too, the base-plates can be sunk into the palatal surface when 
 they interfere with occlusions, as sometimes happens when the 
 antagonism of the lower teeth is very close and the overlap is 
 considerable. 
 
 " Ordinarily, however, such interference is inconsiderable, and 
 the difficulty can always be overcome either in devitalized teeth 
 by the expedient just suggested, or by carrying the base-plates 
 as far away from the cutting-edge as practicable, at the same 
 time making them at the point of contact as thin as is consist- 
 ent with strength ; finally, if necessary, removing a slight 
 portion of the cutting-edge of the occluding lower tooth. . . . 
 
 " As a rule the writer has confined the use of this form of 
 bridge to cases in which only a single incisor is missing, but he 
 has successfully attached a front and lateral incisor to a cuspid 
 and the remaining front incisor. Where an unusual strain 
 is to be expected the retaining-pins and pin-holes should when 
 practicable be made correspondingly large, or two smaller pins 
 may be anchored in one tooth, which latter plan gives very great 
 resisting power. 
 
 " Pin and Plate Attachments to Bicaspids, — Although chiefl}- 
 applicable to the incisors, the pin and plate attachment may be 
 successfully comljined with crown or bar bridges for molars 
 and bicuspids. 
 
 " Fig. 450 represents a practical case in which tlie upper third 
 molar and tlie first bicuspid (both without antagonizing teeth) 
 were utilized for the attachment of a bridge made of gold 
 crowns with porcelain facings, to supply the loss of the interven- 
 ing teeth. 
 
 " Fig. 451 represents the case as prepared for the bridge. A, 
 the inner cus}) of the bicuspid cut down to allow the placing of 
 
PARTIAL CAP AND PIN-BRJDQE METHODS. 
 
 217 
 
 a sufficiently thick crown-plate ; B, a cylindrical undercut open- 
 ing between the cusps for a retain ing-pin; C, the third molar, 
 made uniform in size from neck to grinding-surfoce, the latter 
 
 Fig. 450. 
 
 also being considerably retrenched ; D, the crown-plate of a 
 partial cap, made of pure gold, soldered with 20-carat gold, and 
 so constructed as to cover every portion of the tooth except its 
 
 Fig. 451. 
 
 buccal surface, the free edge passing up under the gum ; E, a 
 
 retaining-pin adapted to the opening B ; P, the gold cap for the 
 
 molar. 
 
 Fig. 452. 
 
 " Fig. 452 represents the bridge anchored in position with 
 oxyphosphate cement. 
 
218 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 " In the above case it will be observed that there is a con- 
 siderable space between the bicuspid and cuspid. This made it 
 readily practicable to give so considerable a thickness to the 
 mesial wall of the partial cap as to hold it securely against the side 
 of the tooth. Had the space been less, contact with the cuspid 
 would have afforded the desired security. 
 
 Fig. 453. 
 
 F 
 
 " Fig, 453 represents another case in which a bridge was at- 
 tached by a bar, partial cap, and retaining-pin. A is an upper 
 second bicuspid (without antagonist) ; B, its inner cusp, cut down ; 
 C, opening for retaining-pin ; D, second molar, with slot for bar; 
 E, cuspid ; F represents the partial facing ; G, the retaining-pin ; 
 H, a molar crown of gold, with porcelain front; I, a platinum 
 bar attached to the crown (H) and made to lit into a slot (at D); 
 
 Fig. 454. 
 
 J, a plain plate cuspid, heavily backed and strongly soldered to 
 the partial cap, but left without attachment to or contact with 
 the cuspid. 
 
 " Fig, 454 shows the bridge anchored in position, 
 " This case, after two years of wear, is still in perfect condi- 
 tion and doing good service. As it was possible to keep the 
 
PARTIAL CAP AND PIN-BRIDGE METHODS. 219 
 
 gold attachments, backings, etc., out of sight, the ajtpearance 
 presented is very natural. 
 
 " The absence of antagonizing teeth for the bicuspids in each 
 of these cases was a favorable condition, as a considerable thick- 
 ness could 1)L' given to the crown-plate without any interference 
 with occlusion. When the conditions are not so favorable, 
 cutting down the inner cusp to the required extent and sinking 
 the opening for the retaining-pin to the necessary depth are pro- 
 cesses certainly to be, as a rule, preferred to the entire removal 
 of the crown for the purpose of ferruling the root for the 
 mounting of a crown of gold and porcelain, — a procedure, how- 
 ever, not by any means to be indiscriminatelj^ denounced, for in 
 many cases it is in the highest degree advisable. 
 
 " There is this fact to be considered in regard to the use of the 
 partial caps here figured, — that many patients can be induced to 
 consent to their employment who would refuse to submit to 
 more radical measures, and thus, even when the latter would be 
 advisable, the former may be employed as a compromise, or even 
 as a temporary- expedient. Having once tested the advantage of 
 a well-fitting bridge, the wearer is much more likely to consent 
 to whatever measures are necessary to give it security and per- 
 manence." 
 
Fig. 455. 
 FOR SHAPIXO SEA]»1L.£SS TOOTH-ROOT COI.L.ARS. 
 
 No. 4. 
 
 Ho. 5. 
 
 No. 6. 
 
 No. 7. 
 
CHAPTER XIII. 
 
 THE MANDREL SYSTEM. 
 
 In all styles of collar crowns the shaping and adapting of the 
 collar is usually found by many dentists to be the most difficult 
 part in their construction. To facilitate its performance the 
 " Mandrel System " was introduced by The S. S. White Dental 
 Manufacturing Co. The following is a revised description taken 
 from an article on the subject:^ 
 
 " An examination of a large number of human teeth shows 
 that, no matter how great differences may exist in the apparent 
 shapes of the crowns of individual teeth of a given class, there 
 is a remarkable uniformity in the configuration of their necks. 
 That is, the necks of upper cuspids, for instance, were found to 
 have a fixed type, from which the variations were very slight as 
 to shape, though there appeared to be no exact standard of size. 
 So of the other classes, with the single exception of the superior 
 molars, in which two distinct forms were found, the first being 
 tliose in which the buccal roots were wider than the palatal : 
 the second, those in which the reverse condition was found, the 
 single palatal root being wider at its junction with the crown 
 than tlie two buccal roots. The occurrence of roots of the 
 second class being rather exceptional, the first class was accepted 
 as the type. 
 
 " The configuration of the necks of all the teeth ha\'ing been 
 determined, a set of mandrels for shaping collars to tit them was 
 devised. The set (Fig. 465) consists of seven mandrels, six of 
 which are double end. Their shapes are modeled upon the 
 general typal forms of the necks of the teeth which they repre- 
 sent, and they are made tapering to provide for all required 
 variations in size. The illustrations are about two-thirds actual 
 
 ^Dental Cosmos, vol. xxviii, No. 8. 
 
 221 
 
222 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 size, the longest instruments being nine inches in length. The 
 cross-sections show the shapes and proportionate sizes at the 
 greatest and least diameters. The long taper permits the most 
 minutely accurate adjustment of the collars. 
 
 " No. 1 is a double-end mandrel, for superior molars, right and 
 left; Ko. 2 is a single mandrel, for superior bicuspids, right -and 
 left; iSTo. 3 is double-end, for superior cuspids, right and left; 
 No. 4, doable-end, for superior centrals, right and left; No. 5, 
 double-end, for inferior molars, right and left ; No. 6, double-end, 
 for the inferior centrals, laterals, cuspids, and first bicuspids, 
 right and left; No. 7, double-end, one end for the superior, 
 lateral incisors, the other for those bicuspids in which a bifur- 
 cation of the roots, or a tendency in that direction, extends 
 across the neck to the crown in the form of a depression on one 
 or both approximal surfaces. The foregoing scheme compre- 
 hends all the teeth of the permanent set except the second 
 inferior bicuspids. The necks of these approximate those of 
 the superior central incisors so closely in shape that it was deemed 
 inexpedient to make a separate mandrel, as the No. 4 mandrel 
 will serve for both. 
 
 " The collars or bands are made seamless, of No. 30 (Ameri- 
 can gauge) gold plate, 22 carats fine. Fifteen sizes, each of 
 three widths {-^, -^-^^ and -^^ inch) are made (Fig. 456), which it 
 is believed will cover all requirements. These collars, although 
 devised as a part of the system, can be used in all methods of 
 crown- and bridge-work which require bands, and possess many 
 advantages over any others. They are really labor-saving 
 de\'ices, as their use saves the time and trouble of making, and 
 there is no danger of their coming unsoldered when the pins or 
 the backing of the crown is being soldered; and there are no 
 hard spots to give trouble in burnishing, as, for instance, close to 
 the root, after the collar has been shaped and placed in position, 
 the whole surface being uniformly soft. 
 
 " The seamless collars are also especially adapted to removable 
 or detachable bridge-work. They arc so constructed that Nos. 
 1, 16, and 31 exactly fit into or telescope with Nos. 2, 17, and 32, 
 and so on through the entire set, each collar fits into the series 
 next higher; so that a root may be banded with one size and 
 
TnE MANDREL SYSTEM. 
 Fig. 4-'>6. 
 
 223 
 
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 OR 
 
 £ 
 
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 ^ 
 
 M 
 
 W 
 
 G 
 
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224 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 the size next larger used to form the tube for the telescoping 
 crown. When desirable, the ' seamless ' collar can be strength- 
 ened, after it has been adapted to the conformation of the crown 
 so as to slide freely over it, by investing and flowing solder over 
 the outer surface ; or, still better, by adapting the next larger 
 size of collar to exactly fit around the first, and then investing 
 
 Fig. 457. 
 
 the two and soldering them together. The advantages of these 
 collars for this style of work, and also for the construction of 
 cap crowns, are ol)vious. 
 
 " The other appliances specially devised for this system are, a 
 reducing-plate or contractor, a pair of collar pliers, and a 
 hammer. 
 
 " The contractor (Fig. 457) contains holes which are comple- 
 
THE MANDREL SYSTEM. 
 
 225 
 
 muntary iu shape to the mandi\'ls. The mandrels being apphed 
 to the inner circumferences of the collars, while the contractor 
 must admit the collars themselves, the short taper of the holes 
 in the contractor necessarily covers a somewhat greater range of 
 
 Fig. 458. 
 
 size than is shown in the mandrels. With this appliance collars 
 can he evenly and accurately reduced in size at the edges, with- 
 out burring or buckling. The illustration is actual size. 
 
 " The collar pliers (Fig. 458) are for contouring the collars to 
 shape, one beak being made convex and the other concave to 
 
 16 
 
226 
 
 ARTIFICIAL CRO WN- AND BRIDGE- WORK. 
 
 Fig. 459. 
 
 correspond. With this appliance the slightest changes required 
 in the contour of the collars are easily made. About a half-inch 
 from the extremity of the concave beak a small 
 bar of flat steel is attached to it by means of a 
 screw. The free end of the bar has a minute 
 projection upon one face, the other being rein- 
 forced to flt into the concavity of the beak. In 
 the center of the face of the convex beak is a 
 depression, into which the projection on the 
 steel bar strikes, making a very efficient punch 
 for forming guards or stops to prevent the col- 
 lars from being forced too far under the gunu 
 The depression in the convex beak being 
 slightly larger than the projection or punch, the 
 metal is not cut through, but merely raised on 
 the side opposite to the punch. The punch 
 attachment being pivoted can be swung to one 
 side when not in use. 
 
 "Fig. 459 is a mallet or hammer, with steel face 
 and horn peen. The handle is nine inches long, 
 " One of the appliances required is a lead 
 anvil, which being only a piece of soft lead say 
 two by tlire^e inches and an inch thick is not 
 illustrated. The female die of an ordinary case 
 will answer very well. 
 
 " To illustrate the uses of these appliances, 
 take a case in which the two inferior bicuspids 
 of the left side are missing, and the crowns 
 of the cuspid and first molar so badly decayed 
 that the probabilities are that they will soon 
 fall victims to the forceps. The old-time way 
 would have been to extract the molar and cus- 
 pid, and make a partial plate. Examination, 
 however, sliows that the roots of these two teeth 
 are in good condition, aftbrding an excellent 
 oi)|)ortunity for the construction of a piece of 
 bridge-work. 
 " With a corundum-point or rotary file, cut ofi' the remaining 
 
THE MANDREL SYSTEM 227 
 
 [(ortions of tlie crowns level with the gum margins. Prepare 
 the roors in an\^ of the well-known ways, thoroughly cleansing 
 the apical portions and filling them with whatever material is 
 desired, being careful only that the work is well done. For the 
 better retention of the filling-material to be placed in the pulp- 
 eharnber, retaining-grooves can be made or retaining-posts in- 
 serted. Take a piece of binding-wire (No. 26, American gauge), 
 two and one-half inches long, pass it around the neck of the molar 
 stump, cross the free ends, and, holding the wire in place with one 
 finger, twist the ends with a pair of flat-nose pliers until the wire 
 clasps the neck closely at every point (Fig. 460). Where there are 
 any irregularities in the contour of the tooth, it is necessary to 
 press the wire into them with an approximal burnisher. It is 
 obvious that the ring thus formed will show the exact size and 
 shape of the neck of the tooth. Remov^e the ring carefully, lay 
 
 Fig. 460. Fig 461. 
 
 it on the lead anvil, put over it a [)iece of flat metal, and with a 
 smart l)low from a hammer drive the wire into the lead (Fig. 
 461). Upon removing the wire an exact im|>ression of the ring- 
 will be left in the lead anvil. (This part of the work, as indeed 
 all others, should be done carefully as described. The wire ring- 
 may be driven into the lead by a direct blow of the hammer 
 face, but the blow might not strike equally, and the interposition 
 of the flat metal held level insures an even impression. A piece 
 of an old file is best, as the file-cuts keep the wire from slipping.) 
 "Next, cut the wire ring at the lap, straighten out the wire, 
 and select a suitable collar by comparing the length of the wire 
 with the straight lines in the diagram (Fig. 456) which show the 
 inside diameters of the various sizes. Should none of these 
 correspond exactly, take preferably the next size smaller. It will 
 be i-emembered that the collars are Xo. 30 in thickness, while 
 
228 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 Fig. 462. 
 
 the wire with which the conformation is secnred is No. 26. This 
 difference permits the collar when contoured to shape to enter 
 the lead impression readily, a decided advantage in fitting. 
 Having selected the collar, fit it to mandrel No. 5, with the peen 
 of the hammer, holding it upon the lead anvil, and using a 
 
 slight pushing force to help in 
 stretching and forming it (Fig. 
 462). Having driven the collar to 
 form, remove it from the mandrel 
 and try in the lead impression. 
 If it does not fit exactly, return 
 it to the mandrel and stretch it a 
 little, when it will usually fit per- 
 fectly, as the mandrels have been 
 designed carefully to the average 
 shapes which obtain in the great 
 majorit}- of tooth-necks. In the 
 exceptional cases where the collar 
 does not fit it can be readily con- 
 toured to the exact shape with a 
 pair of flat-nose pliers. Of course, if it fits the impression in 
 the lead, it will fit the neck of the tooth, always provided the 
 measurement and the impression have been carefully made. 
 
 '•'■ If the collar or band has been accidentally stretched too 
 much, or if for any reason when brought to shape it is too 
 large, its root end can easily be reduced to the proper size by 
 
 Fig. 463. 
 
 Fig, 464. 
 
 m 
 
 the use of the contractor. Place the edge of the collar which 
 is to fit the root in the proper hole ; hold it level with a piece of 
 file as in taking the lead impression of the ring, and tapping 
 lightly on the file drive the collar into the plate (Fig. 463) until 
 the proper reduction is made. The collar is next ' festooned ' 
 to correspond to the shape of the maxillary ridge. Lay it, gum 
 
THE MANDREL SYSTEM. 
 
 229 
 
 edge up, on the lead anvil, and with the piece of flat tile ;;nd 
 the hammer drive it into tlie lead. A feAv cuts with a fine half- 
 round tile across the approximal diameter will conform ihe 
 edges to the surface of the ridge (Fig. 4(34). Then place the 
 collar in position, and, having ascertained just how far it should 
 go dow II on the root, remove it, and with the small spring punch 
 in the collar pliers form projections on the inside of the band at 
 the proper points to serve as stops, which, resting on the top of 
 the root, will prevent the collar from being forced farther down 
 upon it than is desirable (Fig. 4(35). 
 
 " A collar for the cuspid is then iitted in the same manner, 
 using mandrel Xo. (3 for shaping, after which the case is ready 
 for the building of the bridge. 
 
 Fig. 4G5. Fig. 4G6. 
 
 I V 
 
 " Cement with oxyphosphate both collars in position. Then 
 take an impression of the parts, including the interiors of the 
 excavated pulp-chambers, from which make a cast in the usual 
 way. Bend a short piece of half-roujid gold or platinum w ire 
 into the form of a horse-shoe, the two extremities of wliich 
 shall tit into tlie roots of the molar. Then take a longer piece 
 of the same wire, somewhat more than enough to extend from 
 the toe of the horse-shoe when in position to the cuspid root ; 
 bend one end of it at a right angle, or nearly so, to flit the root 
 of the cuspid, and (cutting ofl:' any excess of length) solder the 
 other end to the toe of the horse-shoe. The bar extending 
 between the two roots is the truss of the bridge. Next, place 
 the appliance on the cast (Fig, 466), holding it in position with 
 
230 ARTIFICIAL GROWN- AND BRIDGE- WORK. 
 
 wax, and select the teeth to take the place of the missing- 
 bicuspids and molar. The best form for this purpose is a tooth 
 havino; holes extendino* throus-h it vertically from the neck to 
 the grinding-surface similar to the well-known Bonwill crown. 
 
 " The crowns used should be large enough to fill the space 
 rather tightly, even if their sides have to be flattened slightly to 
 let them in. If the teeth do not fill the space tightly, a small 
 portion of plastic filling-material crowded between them, as 
 mortar between the granite blocks in the arch of a railway 
 bridge, will greatly increase the strength of the work. 
 
 " After the teeth are ground to fit and the proper length for 
 occlusion is ascertained, the truss is covered "svith a thin film of 
 wax, upon which the crowns are again pressed to their positions. 
 Upon the removal of the crowns the impression of the holes 
 running through them will be found in the wax. At these 
 points drill holes through the bar with a small twist-drill run by 
 the engine, and into these fit and solder the pins for the support 
 of the crowns. 
 
 " The bridge is now ready to be attached permanently. Set 
 the crowns in position upon their supporting pins to secure the 
 proper alignment. (If the operation were upon the upper jaw 
 the}' would have to be held with wax.) Put into the canals of 
 the supporting roots (the cuspid and first molar) a suflicicnt 
 quantity of some quick-setting plastic, as oxyphosphate, to about 
 half fill the pulp-chamber, but not enough to prevent the sup- 
 ports of the truss from being forced home. Force the bridge 
 supports to place, and after allowing the filling-material to become 
 set remove'the crowns. Fill the remainder of the pulp-chamber 
 and the whole of the collar with gold or with amalgam, gutta- 
 percha, oxyphosphate, or any suitable plastic (Fig. 467). Set 
 the crowns permanently, the molar and cuspid first, as this 
 afifords greater facility for the trimming off of any excess of the 
 filling-material used in the attachment. For attachment of the 
 crowns, gutta-percha is probably the best material, as crowns 
 set with it are readily removed for the correction of any in- 
 accuracies of occlusion or alignment, by grasping them between 
 the beaks, previously warmed, of a pair of universal lower 
 molar forceps. The heat warms the gutta-percha and releases 
 
THE MANDREL SFSTE.^L 
 
 231 
 
 the tooth, ^vllich can then be re-set properly. In attacliing 
 crowns with gutta-percha the holes in the crowns are first filled 
 with the material, after which the crown is warmed and forced 
 to place. Any of the other plastics ordinarily used in setting 
 
 Fro. 467. 
 
 Bonwill crowns can he employed, at the discretion of the 
 operator. Fig. 468 shows the case completed. 
 
 '' In securing the occlusion of a piece of bridge-work it is well 
 to make the artificial teeth a little short, so that the natural teeth 
 on both sides will meet the first shock of mastication. Xature 
 will correct the occlusion in time by slightly elongating the 
 roots supporting the In-idge. If the artificial crowns are per- 
 mitted to strike the natural teetli from tlie first, the undue strain 
 
 Fig. 4G8. 
 
 upon the two supporting I'oots may cans*.' soreness and perhaps 
 more serious consequences. 
 
 " When a sound tooth is to be used as one of the supports of 
 the bridge, a modification of the method just described is 
 necessary. Take a case where it is desired to bridge the space 
 caused by the loss of the right inferior l)icuspids and first 
 
232 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 molar. The crown of the right cuspid is nearly gone, but the 
 root is sound and capable of supporting one end of the bridge. 
 The other end will be attached to the second molar, which is 
 a sound tooth. Prepare and band the cuspid root as before ; 
 dress off the second molar crown until it is slightly smaller than 
 the neck, and shorter at the occluding surface, so as to permit 
 a cap to be telescoped over it, and take the measure of the 
 crown with the binding-wire. Select a suitable seamless collar 
 of sufficient width to extend from the neck to a little beyond the 
 grinding-surface, and drive it up on the proper mandrel to get 
 the general shape, but not the full size required to fit the tooth, 
 leaving it so that the edge having the larger circumference will 
 just pass over the end of the crown ; place the collar on the 
 tooth, and with a block of wood and the mallet tap it to place 
 
 Fig. 469. 
 
 just l)eyon(l the free margin of the gum. This method will 
 make a close fit, as the collar will readily stretch all that is 
 necessary. With a sharp-pointed instrument mark the length 
 of the crown and line of the gum margin, remove the collar, 
 and cut it to the proper form as indicated. Then in a piece of 
 gold plate of the thickness used for caps form four little depres- 
 sions of the general character of an impression of the molar 
 cusps. An easy way to do this is to lay the plate on the lead 
 anvil ; then with the ball on the end of an ordinary socket- 
 handle and the hammer the depressions are made in a moment. 
 Clamp the collar on the })late, borax it, charge with solder, and 
 heat till the solder fiows. Cut off the surplus plate, and a per- 
 fect cap for the molar is made. Place it on the tooth and take 
 an impression, and thereafter proceed as before directed to make 
 
DETACHABLE BRIDGE- WORK. 
 
 235 
 
 the truss of the bridge and mount the teeth, except tliat in this 
 case the posterior end of the truss is to be sohk'red to tlie molar 
 cap. For the final attachment place a little oxyphosphate in the 
 cap to secure it lirmly (Fig. 469), lirst cutting a slot in the crown 
 end of the cap for the escape of the excess of material. Pressure 
 upon the filling-material hastens its hardening." . . . 
 
 DETACHABLE BRIDGE-WORK. 
 
 " A method of constructing a detachable bridge applicable 
 to cases where one or both of the supports or piers are sound 
 teeth is as follows: In the case adduced for illustration the 
 right inferior cus})id crown was decayed, and both of the bicus- 
 pids and the first molar were absent. The supports for the 
 bridge were the sound second molar and the cuspid root. After 
 the cus})i(l root was [irepared and banded, the crown of the 
 
 Fig. 470. 
 
 molar was reduced very slightly, — not sufficient to destroy the 
 enamel, but just enough to permit a collar })roperly fitted to pass 
 over it. A collar somewhat wider than the lenerth of the crown 
 from grinding-surface to neck was fitted and cut to the prosier 
 width. Two lugs were then soldered upon the anterior and 
 posterior sides and l)ent to fit into the ap})roximal fissures, which 
 were slightly cut out to admit them. An impression was taken, 
 the collar coming away in the plaster, and a cast was made with 
 the collar in position. A coned tube ^^■as then made for the 
 root of the cus[)id and a coned pin fitted into it. A truss of 
 half-round wire was made, to which the coned pin and the molar 
 collar were soldered (Fig, 470). A half-clasp to grasp the lateral 
 was next soldered to the end of the ti'uss to be supported by the 
 
234 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 cuspid. The object of this clasp was to guard against the teeth 
 being thrown out of proper alignment by the force of mastica- 
 tion. Bonwill crowns were then vulcanized to the truss, after 
 their supporting pins had been titted and soldered to it. (Counter- 
 sunk crowns can be used as well in the same way. Plain plate 
 teeth may also be used in this style of work, in which event they 
 are to be soldered to the truss.) The bridge was then ready to 
 be set, which was accomplished in the following manner : The 
 cuspid root was nearly tilled with oxyphosphate, and the coned 
 tube was placed upon the pin. The band was put on the molar, 
 and the coned pin with the tube upon it was forced into the 
 plastic in the cuspid. As soon as this became set, the tube was 
 held permanently, while the bridge itself could be removed when- 
 ever desired (Fig. 471). 
 
 Fig. 471. 
 
 " This method of fixing the tube allows considerable range in 
 its adjustmerlt. In soldering the coned pin to the truss, care 
 should be taken to set it at an angle exactly parallel to the axis 
 of the molar; otherwise there will be difficulty in removing the 
 bridge. 
 
 " A second style of detachable bridge-work to be described 
 involves the use of cusp crowns (Fig. 472) for supporting posts 
 or piers. Suppose a case where a bridge is required to extend from 
 the right inferior cuspid to the right inferior second molar, with 
 only the roots of the two teeth named as supports. Prepare the 
 roots and pulp-chambers. Set screw-posts into the dentine for 
 anchorage or as retaining-pins, and fit the collars, using sizes wide 
 enough to form the walls of the crowns. Fill the pulp-chamber 
 and cement on the collars, filling about two-thirds of the depth of 
 
DETACHABLE BRIDGE-WORK. 
 
 235 
 
 the collars with a plastic filling-material, packing it well around 
 the retaining-posts. Select suitable cusp crowns for the molar 
 and cuspid, and place them in the ends of the bands to ascertain 
 the occlusion. If too long, shorten the cusps or reduce the 
 bands with engine corundums or rotary files, and when the 
 correct articulation is found form a small square shoulder in the 
 lingual edge of the cuspid and in the posterior grinding-surface 
 of the molar. Fill the remaining portion of the collars with 
 plastic mixed somewhat thinner than the first lot, and set the 
 cusp crowms in position. If there are antagonizing teeth the 
 mere closing of the patient's jaws will force the crowns to place. 
 If there are no antagonizing teeth tlie crowns can be readilj- 
 tapped to place with the mallet, using a piece of wood as a 
 driver. Allow the filling-material to set firmly, trimming off 
 any excess which mav exude around the collars. 
 
 '' Bridge supports or piers constructed on this plan are strong 
 and durable, and likely to withstand any strain. Take an 
 impression, and proceed to fit seamless collars to telescope over 
 those already set upon the cuspid and second molar roots. It 
 will be rememl)ered that these collars are so made that each size 
 telescopes into the next higher series. If the proper sizes are 
 selected for the outside or female bands, the work of fitting is 
 readily and quickly accom}tlished, forming tubes which slide 
 easil}' over the supporting piers, and at the same time fit closelj'. 
 It is only necessary to take care in shaping the tubes not to drive 
 them too far up on the mandrels and thus stretch them so as to 
 destroy the fit. To the outer end of each of the tubes solder a 
 small piece of gold plate, forming partial caps so placed as to 
 rest when in position upon the shoulders previously cut in the 
 cusp crowns. Adjust a truss bar of half-round gold wire, to the 
 ends of which solder the tubes. The truss is now readv for the 
 
236 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 teeth, which may be of any of the forms used for this purpose, 
 and the}^ may be attached to the bar in any way desired. One 
 of the strongest attachments is vulcanite. Fig. 473 shows the 
 construction and the finished case. 
 
 Fig. 473. 
 
 " A.n easy moditicatiou of the plan just described is readily 
 adapted to cases where only a small space is to be filled and one 
 end of the bridge is to be supported by a sound tooth. Thus, 
 suppose it is desired to bridge a space formerly occupied by the 
 two inferior left bicuspids, the crown of the first molar being a 
 mere shell. The operation would be essentially the same as in 
 
 Fig. 474. 
 
 Fig. 475. 
 
 the previous case, except that the sound cuspid would be utilized 
 for one of the piers as follows : Fit a seamless collar, cut out a 
 portion of it so that it will embrace only about two-thirds of the 
 cuspid crown, and solder a partial cap or cover to it, as illustrated 
 
DETA CHA BLE BRIDGE- WORK. 237 
 
 in Fig. 474. Or, if deemed preferahle, the cuspid may be separ- 
 ated from the lateral incisor with the corundum-disk and the 
 collar allowed to embrace the whole crown. 
 
 " A crown broken from a bridgt constructed by any of the 
 methods above described can be easily substituted, and the piece 
 when repaired will be as strong and serviceable as it was 
 
 orio'inall}'. 
 
 Fig 470. 
 
 " It has not been deemed necessary to detail the construction 
 of a single crown separately, as all the steps are included in the 
 building of bridges, which have been described minutely. Por- 
 celain cusps of the general form illustrated in Fig. 475 have been 
 designed specially for these cases. In mounting them the gold 
 band is cut away on the buccal side as shown in Fig. 476 to 
 permit the porcelain to show." 
 
CHAPTER XIV. 
 
 PORCELAIN BRIDGE-WORK. 
 
 For an ideal piece of bridge-work that will dispense with the 
 objectionable features of a permanently attached bridge and 
 refute the most forcible arguments against the system, porcelain 
 is the most suitable material known. 
 
 DR. BROWN'S METHOD. 
 
 Dr. E. Parmly Brown, of Flushing, N. Y., has invented and 
 introduced a method of porcelain and iridio-platinum bridge- 
 work, which possesses special merit. 
 
 The advantages claimed for it as a method of bridge-work are 
 as follows : 
 
 It is formed entirely of porcelain with an iridio-platinum bar 
 running through the denture as a sustaining shaft, thus present- 
 ing a perfect continuity of porcelain surface. 
 
 It is unaffected by any chemical action or condition in the 
 mouth. It has no so-called self-cleansing spaces, because none 
 are required. 
 
 A benign and natural form of contour is presented on its 
 palatal surface, as the base of each tooth presses tightly onto the 
 membranes of the gum, which closes or hugs closely around it. 
 
 And lastly, it has the merit of simplicity of construction in 
 comparison with the other methods in practice. 
 
 Construct iov. — The bridge is formed by spanning intervening 
 spaces between certain natural teeth or roots with artificial 
 porcelain substitutes baked onto an iridio-platinum bar; either or 
 both ends of the bar being anchored in a crown, or in a filling 
 inserted in the approximal portion of the adjoining tooth. The 
 ■roots to be crowned and used as foundations for the bridge are 
 prepared as for single crowns. If the end of the bar is to be 
 238 
 
PORCELAIN BRIDGE- WORK. 289 
 
 Hxed in a natural tooth, the cavity that is to receive and anchor 
 it is opened up sufficient to admit it, — in the bicuspids and mo- 
 lars from the grinding-surface to the cervico-approximal edge, 
 and in the incisors, on the approximal side, with an opening on 
 the palatal or labial face, as indicated. A square bar of iridio- 
 platinum wire from ^o. 13 to Xo. 15, U. S. standard gauge, in 
 thickness, is fitted either to the cavities of the teeth in which it is 
 to be anchored, or bent and fitted in any devitalized tooth or root 
 which is to act as an abutment. The end of the wire that forms 
 the post is pointed and introduced well up the root-canal, and 
 the end forming the bar is slightly flattened or squared. Any 
 intervening root-posts are fitted and riveted to the bar as it 
 passes above them. 
 
 To this bar the teeth used, which are ordinary Fio. 477. 
 plate teeth,^ are fastened : incisors by slightly 
 flattening the bar and riveting them fiist, or when 
 straight-pin teeth are used by bending the pins 
 over the bar (Fig. 477) ; bicuspids and molars with 
 straight pins, by grinding a slot with a disk l)e- 
 tween the pins and bending them over the bar, which is slightly 
 barbed and set in the slot. 
 
 The proper position of each tooth having been determined by 
 adjustment in the mouth, or to the articulating model, the rivets 
 and bar on each tootli are carefully filled around and the cervico- 
 palatal portion rounded ofl" with porcelain body so as to present 
 a natural surface to the tongue. The shape of the end of the 
 root is given to the crown by placing the porcelain body, to 
 which a small quantity of starch has been added, around the 
 post as it is fixed in position on the model; the plaster having 
 been previously varnished with collodion to prevent cohesion. 
 The spaces between the teeth on the line of the bar are to be 
 substantially joined with the porcelain body; free spaces between 
 the teeth at the cervical portion are to be preserved as much as 
 possible without interfering with strength or producing places 
 that will be uncleanh*. 
 
 1 Dr. Brown uses The 8. 6. White Dental Mfg. Co.'s teeth entirely forthis work, 
 as he has found them the most suitable, being the only kind that will retain their 
 color in the intense heat to which they are suhjecied. 
 
240 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 The bridge is then placed on a slide in the muffle of a con- 
 tinuous-gum furnace, being sustained in position bv inserting 
 the pins in holes drilled in the side (Fig. 478) or by suspending 
 it with platinum wirebetwef n two platinum posts inserted in the' 
 slab, and then baked the same as for con tinuous-gum work. The 
 brido:e is next fitted to the mouth. If any alterations are re- 
 quired they should be made, or if any imperfections in the body 
 occur the places should be filled in and the bridge again baked. 
 It is then ready for insertion. 
 
 Insertion. — When the bridge is supported by crowns alone, the 
 posts are barbed and the bridge is then cemented on, the same 
 as any other. If one end is supported on a crown and the 
 other by a bar, the filling on the bar end is inserted up to the 
 
 Fig. 478. 
 
 position the bar is to occupy before fastening the pin of the crown 
 end, which is then cemented and the filling of the bar end com- 
 pleted. If both ends are bars, both fillings are inserted up to 
 the position of the bars, the bridge inserted, and the fillings 
 finished; the bridge being held by an instrument or the fingers 
 until the bar ends are partly covered. 
 
 When gold is used, the rul)ber-dam should first be applied, 
 and the cervical portion of the teeth of the bridge pressed 
 tightly into it to avoid any space being left after its removal and 
 the completion of the operation. 
 
 When amalgam is used, the rubber-dam is not necessary. 
 
 In Fig. 479, No. 1 is a third molar, pulp alive, with large 
 filling; No. 2 is a porcelain bridge; No. 3 is a first molar, pulp 
 dead, with a metal bar entering the pulp-chamber. 
 
PORCELAIN BRIDGE- WORK. 
 
 241 
 
 111 Fig. 480, N'o. 1 is a second molar, pulp alive, with a crown 
 filling of gold or amalgam retaining the bar; No. 2 is a porce- 
 lain bridge; No. 3 is a gold crown with bar passing through 
 one side of the crown into the root. 
 
 Fig. 481 is a view of a bridge of two teeth, — a central porce- 
 
 FiG. 479. 
 
 Fig. 480. 
 
 Fig. 481. 
 
 lain crown with a lateral baked onto it, the bar and pin being of 
 the same piece, bent at al)out a right angle. 
 
 In Fig. 481, No. 1 is a porcelain crown forming part of the 
 bridge; No. 2 a bridged lateral with metal bar baked through 
 it; No. 3 a living cuspid with a metal bar running into the 
 center of a solid gold filling. 
 
 Fig. 482. 
 
 Fig. 484. 
 
 Fig. 483. 
 
 Fig. 482 is a view of a central incisor bridged onto two teeth 
 whose pulps have been lost. 
 
 Fig. 483 is a view of the attachment of the bridge to a natural 
 or artificial crown standing alone. The bar can be anchored in 
 
 16 
 
242 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 a filling in the natural crown or attached to the artificial one. 
 ISTos. 1 and 3 are teeth on a porcelain bridge ; i^o. 2 the natural 
 tooth or artificial crown on which the bridge is saddled. 
 
 Figs. 484, 485, and 486 represent a bridge of eleven teeth 
 
 Fig. 485. 
 
 Fig. 486. 
 
 recently inserted by Dr. Brown on two cuspid roots, a pulpless 
 molar on the left side which was capped with a gold crown, 
 
 Fig. 487, 
 
 through the side of which the bar was passed and anchored in 
 the root, and a molar on the right side into which the other end 
 of the bar was anchored in a gold filling. 
 
 Fig. 487 represents a bicuspid bar-bridge anchored in the molar 
 
PORCELAIN BRIDGE-WORK. 
 
 248 
 
 and first bicuspid. Tiie side cut shows the construction. This 
 operation was performed by Dr. Brown for Dr. Crenshaw, of 
 Atlanta, Georgia, at the anniversary clinic of the First District 
 Dental Society of the State of New York, in January, 1887. 
 
 Fig. 488 represents an extension bridge in which the abut- 
 ment consists of a crown and bar combined. 
 
 Fig. 489 represents an extension ])ar-bridge. The filling in 
 
 Fig. 488. 
 
 Fig. 489. 
 
 '^\^ ^' 
 
 the second bicuspid, which extended from the mesial to the 
 distal side, had been inserted some time previously. Enough of 
 the gold was removed from the mesial section of the filling to 
 admit the bar, which was then securely anchored and the filling 
 I'cstored to its original form. The operation was performed by 
 
 Fig. 490. 
 
 Dr. l>rown for Dr. F. P. Hamlet, and to present date has been 
 worn two years. The antagonizing teeth in the act of occlusion 
 favor the artificial tooth forming the bridge. 
 
 In porcelain bridge-work, should a case require it, artificial 
 o-um in a moderate amount can be formed above the teeth of 
 
244 
 
 ARTIFICIAL CROWN- AND BRIDGE-WORK. 
 
 the bridge, to restore the contour of the parts. Figs. 490 and 
 491 ilkistrate a case of this character. A, Fig. 492, shows the 
 labial and B the Ungual aspect of the incisor bridge before 
 insertion. 
 
 Fig. 491. 
 
 Fig. 492. 
 
 In forming this style of porcelain bridge, when it is considered 
 preferable to cap the roots, platinum plate can be struck up for 
 the purpose as described at page 100, and after lieing adjusted 
 
 Fig. 493. 
 
 to the ends of the roots the posts are passed through them, as 
 illustrated in Fig. 493. Cap and bar are then soldered together 
 with a very small quantity of pure gold, and the construction of 
 
 the bridge continued. 
 
PORCELAIN BRIDGE- WORK. 
 
 245 
 
 Fig. 494 represents a case recently restored \)\ Dr. Brown's 
 method by Dr. M. L. Rhein, of IS'ew York. To remedy the 
 abnormal character of the occlusion, the lower anterior teeth 
 and the right upper cuspid were trimmed to the dotted line seen 
 in the figure. To replace the missing teeth porcelain bridge- 
 work was then constructed. Tlie lateral and central roots, and 
 
 Fio. 494. 
 
 the right cuspid and the molar, constituted the abutments. On the 
 central and lateral roots were mounted caps with collars. A 
 platinum crown was then made for the cuspid (Fig. 495), and to 
 this crown was attached the bar, which was extended to its 
 anchorages in the molar crown and the lateral and central roots, 
 the caps on the ends of which the posts pierced. Owing to the 
 large (piantity of porcelain body to be used in forming the artificial 
 
 Fig. 495. 
 
 Fig. 496. 
 
 gum, a strip of platinum plate was extended aliove the bar to 
 stiffen its projecting ends and prevent warpage in baking. The 
 artificial teeth were then articulated to meet the incisive edges of 
 the inferior natural teeth, and thus in a measure overcome the 
 deformity caused by the abnormal occlusion. In doing this the 
 labial aspect of the cuspid was covered by the artificial teeth. Por- 
 celain gum was then formed above the teeth to restore the contour 
 
246 
 
 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 of the parts. Fig. 496 shows the finished bridge. In Fig. 497 
 the bridge is seen in position. The artistic result and improved 
 appearance effected are at once apparent. The mechanical con- 
 struction of the piece was intrusted to Dr. C. L. Andrews. 
 
 Dr. Brown's system and method of bridge-work compares 
 with other forms of bridge-work as continuous-gum work com- 
 pares with other forms of plate-work. Its cleanliness, through 
 
 Fig. 497. 
 
 the unalterable character and continuity of its surface and the 
 incorruptibility of the material, renders it a superior form of 
 denture. 
 
 The ultimate value of this method, however, as a means of 
 replacing lost members of the dental arch, depends, like others, 
 on its proper, correct, and skillful application to cases suitable 
 for it. . 
 
PAET lY. 
 
 MATERIALS AND PROCESSES USED IN CROWN- AND 
 BRIDGE-WORK. 
 
CHAPTER I. 
 
 PLATE AND SOLDERS. 
 
 Phitc — In the construction of crown- and briclgc-work, g"o](L 
 platinum, or iridio-platinum are used in the following forms 
 and grades in carat, as suits the requirement of the case and the 
 preference of the dentist : 
 
 Gold plate, 24 carats, from Xo. 32 to Xo. 34 U. S. standard 
 gauge, for constructing the collars and caps to collars of crown?^ 
 and seamless crowns, and for l)acking porcelain fronts. 
 
 Gold plate, slightly alloyed, — about 23 (.'arats fine, — in crown- 
 work, if less iiexibility of the metal is required. 
 
 Gold plate, 22 carats, No. 32 to JSTo. 34 standard gauge, in 
 constructing collars for crowns with porcelain fronts and all- 
 gold crowns constructed in sections. 
 
 Gold plate, 20 carats, in construction of bridge-work. 
 
 Gold plate, 24 carats, with a very thin lining of platinum, oi' 
 iridio-platinum plate, can be used in any of the processes con- 
 nected with crown- and bridge-work, and is especially reconi- 
 mendedto the inexperienced, for the reason that the melting of a 
 part of a crown in the soldering process is prevented by its use. 
 It is formed by placing together an annealed gold plate and a plat- 
 inum plate (the gold about ]^o. 20 gauge and the i)latinum Xo. 
 30) and passing them through a rolling-mill, in which process the 
 plates are welded and reduced to the desired thickness. 
 
 Pure platinum rolled very thin is used for forming caps to 
 collars, backing teeth, and for various purposes connected with 
 this class of operations. Iridio-platinum wire is used for [livots. 
 pins, or posts, being more rigid than pure platinum. A wire 
 of gold and platinum alloy is used on account of its elasticity 
 for split or spring pivots or posts in removable bridge-work. 
 
 Solders. — Gold solder, 22 carats fine, is used for crown-woik 
 20 carats for crown- and bridge-work. 
 
 249 
 
250 ARTIFICIAL GROWN- AND BRIDGE-WORK. 
 
 18 carats is used for crown- and bridge-work, but this is con- 
 sidered by some too low a carat. 
 
 14 carats for strengthening seamless crowns : used only in 
 crowning operations. 
 
 Successive grades of solder from hard to easy flowing can be 
 used in the regular soldering of crown- and bridge-work ; gold 
 plate for the first, a hard-flowing solder for the next, and an 
 easy-flowing one for the finish. This avoids melting or flowing 
 of the gold at any point previously soldered. 
 
 Any grade of solder can be made according to the following 
 formula : 
 
 Zinc, \h grs. ; 
 Pure gold, 
 
 Silver solder, in quantity suflBcient to make up the 22\ 
 remaining parts in weight. 
 
 The quantity of silver solder used will regulate the grade in 
 carat of the solder. Thus : 
 
 Zinc, \\ grs.; 
 Pure gold, 20 grs. ; 
 Silver solder, 3 grs., 
 
 will, by the burning out of a portion of the zinc in the process, 
 make a solder about 20 carats fine. 
 
 By lessening the proportion of zinc from IJ grains to 1 grain, 
 tlie proportion of silver solder being kept the same, the solder 
 will become harder-flowing and a little finer. 
 
 Dr. W. H. Dorrance recommends the following formula as an 
 alloy for the formation of difierent grades of gold solders, the 
 proportion of the alloy used determining the melting point and 
 fineness in carat of the solder : 
 
 1 part pure silver ; 
 
 2 parts pure zinc ; 
 
 3 parts pure copper. 
 
 The silver and copper are first melted together in a crucible 
 lined with borax and the zinc added quickly in small pieces, 
 stirring the mass meantime with a pipe-clay stem. It is then, 
 on the fumes of the zinc passing otf, immediately poured into 
 an ingot-mold or into a large wooden pail filled with water; 
 4 grains of this alloy melted with 20 grains of pure gold will 
 result in a solder fully 20 carats fine. 
 
PLATE AND SOLDERS. 251 
 
 As a solder for crown- and l)ridge-work constructed of 22- 
 carat gold plate, Dr. Litch's formula is as follows : 
 
 Gold coin (ten dollars), 238 grs. ; 
 Spelter (or brazier's solder), 24 grs. ; 
 Silver coin, 24 grs. 
 
 This is a proportion of about 26 grains of pure copper and 232 
 grains of pure gold to the remaining 48 grains of the alloy, and 
 makes a gold solder a little over 18 carats fine. 
 
 Dr. C. M. Richmond originally used American gold coin for 
 forming gold crowns, rolling it out in the form of plate. The 
 scraps he formed into solder l\v melting and adding in small 
 pieces one-fifth of their weight of fine brass wire cut in small 
 pieces, using plenty of borax. 
 
 Dr. Low's formula for solder in bridge-work is : 
 
 1 dwt. coin gold ; 
 
 2 grs. copper; 
 4 grs. silver. 
 
 This makes a solder about 19 carats fine. 
 
CHAPTER 11. 
 
 PORCELAIN TEETH. 
 
 The qualities specially requisite in the body of porcelain teetli 
 for use in crown- and bridge-work are density, strength, and the 
 ability to withstand unaltered in form or shade any degree 
 of heat to which they may necessarily be subjected. In these 
 respects the porcelain teeth of our best American manufacture 
 seem to excel, besides affording the most artistic imitation of 
 the natural teeth in form and shade. They are also distinguished 
 by the practical location of the pins. 
 
 In some crowning operations, where to imitate the conforma- 
 tion of a natural crown considerable alteration of the labial 
 surface of a porcelain front is required, teeth of English manu- 
 facture may be used, as the texture of the porcelain admits of a 
 tine polish being given to a ground surface. 
 
 Teeth are sometimes fractured in the process of soldering,, 
 caused by the contraction of the backing when adapted over 
 the edges of the porcelain in a curve instead of at a right or 
 slightly obtuse angle, or by melting solder on some point of the 
 porcelain which is unprotected by a backing of metal. The 
 solder, or the borax, as it cools, contracting on the porcelain, or 
 a very thin edge of the metal covering it, will usually cause a 
 fracture. The porcelain tooth has yet to be made that will, as a 
 rule, endure such extreme treatment without breaking. 
 
 252 
 
CHAPTER III. 
 
 MOLDS AND DIES. 
 
 Metallic models of fusible metal can be easily and quieklj^ 
 formed for use in crown- and bridge-work. The melted' alloy 
 can be poured into a plaster, moldine, or gutta-percha impression 
 taken in a tube or impression-tray. When a tube is used, a strip 
 of paper should be wound around it to lengthen the die. 
 
 The following fusible alloys of tin are suitable for the purpose : 
 
 
 PROPORTIOXS OI- 
 
 METALS. 
 
 
 MELTING POIXT OK 
 THE ALLOY. 
 
 Tin. 
 
 Lead. 
 
 
 Bismuth. 
 
 Fahr. 
 
 1 
 
 •2 
 
 
 2 
 
 286° 
 
 5 
 
 3 
 
 
 3 
 
 202° 
 
 3 
 
 5 
 
 
 8 
 
 197° 
 
 Dr. G. W. Melotte, of Ithaca, N. Y., to whom is accorded the 
 credit of introducing the use of fusible metal and the compound 
 called " moldine " into crown- and bridge-work, gives the propor- 
 tions of his alloy in parts as — 
 
 Tin, .5; Lead, 3; Bismuth, 8. 
 
 Dr. Melotte's moldine, a preparation compounded of potter's 
 chiy and glycerin (to which, when needed to soften it, more 
 glycerin can he added), is very useful in molding. 
 
 A counter-die to a small cast or die of fusible metal is made 
 l)y indenting a block of lead with a punch, and then driving the 
 cast or die into it. Its use in crown-work is described on pages 
 90, 99, and 103, and by Dr. Melotte on page 209. 
 
 The following method of forming a metallic model of a pre- 
 pared root or crown is given by Dr. W. C. Barrett, of Buffalo, 
 N. y,, who accords Dr. H. A. Baker, of Boston, the credit of 
 being the originator of it : 
 
 "Copper is rolled down quite thin, and a band three-fourths 
 
 253 
 
254 ARTIFICIAL GROWN- AND BRIDGE-WORK. 
 
 of an inch wide wrapped about the root and forced up under 
 the gum. A Ugature is passed around both; the copper band 
 is burnished down and the hgature drawn tight. The copper 
 band will now fit just as we want the gold band to do. Plaster 
 of Paris is then inserted in this, forced up against the end of 
 the root, and permitted to set. Take it off, and if you use 
 Babbitt-metal, a piece of paper wrapped about it (tlie copper 
 band) will lengthen it out sufficiently, when the metal may be 
 poured into it, and thus a perfect model of the end of the root 
 will be secured. That part that is inserted in the copper tube is 
 the exact reproduction of the root of the tooth. The model 
 will perhaps need a little dressing down with a file, when the 
 o-old band may be fitted around it and soldered, thus avoiding 
 the necessitj^ for the annoying and painful trying-on in the 
 mouth." 
 
 Fusible metal can be used instead of Babbitt-metal. 
 
Fig. 498. 
 
 CHAPTER IV. 
 
 SOLDERING. 
 
 InrestiiK'nis for soliJering, and models 
 on which the soldering is to be done for 
 bridge-work, are made in calcined mar- 
 ble-dust and plaster, in the })r()portion 
 of equal parts for models, and one part 
 of plaster to two of marble-dust for 
 investing. Sulphate of potassium, used 
 in place of common salt, but in a smaller 
 quantity, will cause the mixture to set 
 quickly and hard. 
 
 Soldering. — In soldering crown- and 
 bridge-Avork or sections of it containing 
 porcelain fronts, the investment should 
 be first uniformly and thoroughly 
 heated, and the heat maintained during 
 the process of soldering. This is espe- 
 ciall}' necessary in the final soldering of 
 gold crowns with porcelain fronts, as 
 the solder is thereby flowed into the 
 interstices between the porcelain and 
 the ca[»s and gives continuity of struc- 
 ture to the crown. A large piece of 
 charcoal, concave on the side to be used, 
 furnishes a good soldering support, as 
 it retains the heat. A hand gas blow- 
 pipe, operated by a foot bellows, and 
 so constructed that the flame is under 
 perfect control, is the most suitable (Fig. 
 498). 
 
 77/e i/sc of Borax. — In soldering in- 
 vested sections of a crown or bridge 
 
 256 
 
256 ARTIFICIAL CROWN- AND BRIDGE- WORK. 
 
 together, borax which has been reduced to a vitreous state by 
 heat and then finely pulverized is the preferred form for its use. 
 Prepared in this manner it should be sprinkled on the part pre- 
 vious to the commencement of the soldering, and a little added 
 at any time it is needed during the continuance of the process. 
 
 In small, fine soldering of invested or uninvested work, the 
 lump borax ground with water on a slab to a cream-like con- 
 sistence and applied with the point of a stick or brush only 
 where it is desired to have the solder flow, is the most suitable. 
 
CHAPTER V. 
 
 INSTRUMENTS AND APrLIANCES. 
 
 The dentist who intends to engage extensivel}^ in erown- and 
 bridge-work, and wlio desires to practice it convenientl>' and 
 successfully, should siqi[>l_v liimself with all the necessary instru- 
 ments, tools, and other appliances. These consist principally oi 
 
 Fm. 409. 
 
 drills of various styles, among them the Gates-Glidden for root- 
 canals; root-trimming and shaping instruments; corundum- 
 wheels and points; rubber and corundum disks; a set of steel 
 mandrels, with a contracting plate and suitably shaped pliers; a 
 supply of clamps of various forms for use in the many soldering 
 processes; some moldine and fusible alloy, and an apparatus for 
 forming gold caps for use in constructing crowns; a Lee blow- 
 pipe or Knapp's compound blow-pipe, or both, for use as is most 
 suitable or convenient, 
 
 17 257 
 
258 
 
 ARTIFICIAL GROWN- AND BRIDGE-WORK. 
 
 The bench on which the principal parts of the work are done 
 should be specially designed and reserved for it. It should be 
 very convenient to the dental chair, and if in the same room 
 should be situated a little behind it, out of view of the patient. 
 Everything connected with this bench should be kept in order 
 
 Fig. 500. 
 
 and ready for immediate use. Such a l)ench, made of black 
 walnut, with a top that can be closed when not in use, making 
 an unobjectionable piece of furniture, is represented in Figs. 
 499 and 500. 
 
 ERRATA. 
 
 On page 39, third line, for " above " road " below." 
 " " 159, eighth line, for " approximal " read " palatal." 
 
1 1^ 1 ) E X. 
 
 Abrasion of incisive edges of teeth, 95 
 .method of forming crown for, 116 
 Abscess, chronic alveolar, treatment of, 33 
 Acid, arsenious, its use and action in devi- 
 talizing pulps, 26 
 Acid secretions, platinum unaffected by, 98 
 Adjuster for use in cementation of crowns, 
 
 129 
 Adjustment of finished bridge-work in the 
 
 mouth, 144 
 Alloy for forming any grade of gold solder, 
 
 250 
 Alloys of tin, their use in crown and bridge- 
 work, 25.3 
 Alveolar absceFs, classification of, .33 
 
 treatment of, 33 
 Amputation of the apex of a root, 35 
 Analysis of dentine, 24 
 Anatomical structure of dentine, 23 
 Anchorage bars in bridge-work, 142, 159, 2311 
 manner of attaching to the abutiiient<, 
 
 139, 144,240 
 manner of forming, 144, 160 
 Anchorages for bridge-work, preparation 
 of, 139, 149, 249 
 Dr. Litch's method, 212 
 Dr. Parr's, 183 
 shell, 151 
 Ancient bridge-work, 133 
 Anesthesia in ])ulp-extraction, 25 
 Anesthetics, local, for application to gum, 
 
 34, 36 
 Antagonizing teeth, preparation of their 
 
 cusps, 39 
 Antiseptic agents in treatment of alveolar 
 abscess, 35 
 in treatment of devitalized teeth, 31 
 Articulation for bridge-work, manner of 
 
 taking, 140 
 Artificial crown-work, 17, 41 
 the gold system, 77 
 the porcelain system, 44 
 Artificial gum in porcelain bridge- work, 243 
 
 Backings for ])orcelain fronts in crown- 
 work, !^5 
 Baldwin's method of mounting crowns, 71 
 Bars for bridges, 150 
 Beers's crown. 79 
 Bing's bridge-work, 134 
 Blow-pipe, Lee's, 255 
 
 Knapp's carbo-oxyhydrogon, 205 
 Bonwill's porcelain crowns, 45 
 Borax, method of using in crown- ami 
 bridge-work, in constructing root-caps 
 and tubes, ISS 
 Bridge work, 131 
 
 adjustment and insertion, 144 
 
 an impartial criticism of, 134 
 
 cantilever, 158 
 
 cases illustrating the application of, 1 62 
 
 cementation of, 128 
 
 construction of, 137, 147 
 
 detachable, 172, 233 
 
 double-bar, 159 
 
 extension, 155, 195, 243 
 
 foundations for, 137 
 
 manner of taking impression and ar- 
 ticulation for, 139 
 
 mechanical principles governing the 
 selection of abutments, 137 
 
 partial cap and pin, 212 
 
 porcelain, 238 
 
 removable. 172, 187 
 
 removal of, 171 
 
 with replaceable porcelain fronts, 160 
 Brown's porcelain crowns, 65 
 
 bridge-work, 238 
 Burnishers for adapting collars, 83 
 
 Cementation of crown- or bridge-work, 128 
 Chronic alveolar abscess, 33 
 Clamps, soldering. 91 
 Collar contractor, 224 
 
 crowns hygienically oon.sidered, 98 
 
 pliers, 225 
 Collars for crowns, 79, 221 
 
 259 
 
260 
 
 INDEX. 
 
 Collars, construction and adaptation of, 7'J 
 Construction of bridge-work, 137 
 
 detachable and removable, 172, 233 
 
 mecbanical principles governing, 137 
 
 plate, 1S7 
 
 saddles, 155, 166 
 
 single and double bar, 150, 15S, 159 
 
 small cases of, 147 
 
 special processes and appliances in, 148 
 Corundum-wheels and points, 37, 38 
 Crowns, artificial : — 
 
 Baldwin's method of mounting, 71 
 
 Bonwill, 45 
 
 Bonwill cap, 72 
 
 Brown, 61, 65 
 
 Farrar's cantilever, 96 
 
 Foster, 59 
 
 Gates, 58 
 
 How. 51 
 
 Howland, 59 
 
 Kirk's method of mounting, 70 
 
 Leech, 118 
 
 Logan, 61 
 
 Low, 119 
 
 new Riehuiond, fil, 66 
 
 Parr, 117 
 
 Richmond, 182 
 
 Stowell's metboil of mounting, 88 
 
 Van Woert, 78 
 
 AVeston, 73 
 
 all-gold, in sections, 89 
 
 attachments for all-gold and seamless 
 gold, 39, 40, 111, 112 
 
 cementation, process of, 128 
 
 contouring of collars, 107 
 
 countersunk, 88 
 
 dies for use in construction of, 92 
 
 expan<ling, 109 
 
 finishing and polishing, 128 
 
 for separate molar roots, 95 
 
 gold and porcelain, for teeth with living 
 pulps, 113 
 
 gold and porcelain, without a collar, 77 
 
 gold collar, 79 
 
 gold seamless cap, 99, 108 
 
 gold seamless contour, 105 
 
 mandrel system, 221 
 
 partial, 124 
 
 porcelain, with collar attachment, 70 
 
 porcelain, with rubber attachment, 76 
 
 prcjjaration of crown or root for. 21, 37 
 
 Crowns, artificial (continued): — 
 
 process of adjustment of gold contour 
 
 seamless, 108 
 remarks on the use of collar or porce- 
 lain crowns, 69, 98 
 removal of, 171 
 repair of, 170 
 shell, 151, 156 
 
 Detachable bridge- work, 172 
 i)etachable porcelain front, 160 
 Devitalization of pulps, 25 
 
 heroic or instantaneous, 25 
 
 use of arsenic for, 26 
 Dies, 87,90,92,99,103, 114 
 
 counter, 90, 103' 
 
 Dr. Baker's method, 253 
 
 Dr. Melotte's. method for forming, 209 
 
 fusible metal, 253 
 
 manner of obtaining molds and dies, 
 99, 253 
 Diseased pulps, classification of. requiring 
 
 extirpation, 24 
 Disks, forms of, 38 
 Double bar-bridges, 159, 239, 240, 241, 242 
 
 244 
 Drills, Gates-Glidden. form of and method 
 
 of using, 29 
 Dummies, definition of, 143 
 Dwinelle's crown, 79 
 
 E.xcision of crown, 25 
 when to avoid, 38 
 E.xpansion of a collar or crown. 109 
 Extension bar-bridge, 243 
 Extension bridges, 155, 195, 243 
 Extirpation of pulps, 22, 25 
 
 Farrar's cantilever crown, 96 
 
 Ferrules for roots or crowns, 79 
 
 Files for trimming roots or crowns, 38 
 
 Filling of root-canals, 31 
 
 Finishing and polishing bridge-work, 144 
 
 crown-work, 128 
 Forceps for excising crowns, 26 
 
 for repairing, 170 
 Formulas for fusible metals, 253 
 
 for gold solders, 250 
 Foster crown, 59 
 
 Foundations for bridge-work, 137 
 Fracfnire of porcelain teeth in soldering, 262 
 
IXDEX. 
 
 201 
 
 Fnictured crowns and roots, treatment for 
 
 crowning, 121 
 Fusible alloys of tin, 253 
 Melotte's, 253 
 
 Gates's crown, 58 
 Gold collar crowns, 79 
 
 preparing natural teeth for, 38 
 Gold plate lined with platinum, 249 
 
 crown metal, 249 
 
 solders, formulas for, 250 
 
 standard of carat and gauge required, 
 249 
 
 wire. 249 
 Gutta-percha for forming molds of crowns 
 or roots, 99 
 
 in filling root-canals, 31 
 
 in preparation of roots, 39 
 
 use of, for cementing crown and bridge- 
 work, 130 
 
 Hollow wire for posts, 85 
 
 How crowns, 5 I 
 
 How screws, 52, 59 
 
 Howland crown, 50 
 
 Hub-mold, 92 
 
 Hygienic jireparation of the mouth. 21 
 
 Impressions of crowns or roots. 47. 99. 102 
 
 cups. 86 
 
 for bridge-work, 140 
 
 impression and articulation combined. 
 140 
 
 materials for taking. 80. 139 
 Instantaneous devitalization, 25 
 Instruments and appliances, 257 
 Investments for soldering, 255 
 
 in bridge-work. 143 
 
 in crown-work, 86 
 Iridio-platinum wire for posts, 249 
 Irregularities of the toeth, methods of 
 crowning in, 122 
 
 Judicial decision regarding the ])ublio use 
 of bridge- work, 198 
 
 Kingsley's method of forming all -gold 
 crowns, 91 
 
 Kirk's method, 70 
 
 Knapp's methods in crown- and bridge- 
 work, 203 
 
 Lead counter-dies, method of forming, 253 
 
 Leech's crown, 118 
 
 Litch's method of crowning, 101 
 detachable bridge, 174 
 partial cap and pin bridge, 212 
 
 Logan crown, 61 
 
 Dr. Baldwin's method of mounting, 7 1 
 
 Low bridge. 1 98 
 
 Low crown. 119 
 
 Mandrel system, 220 
 Mandrels for forming collars. SO. 220 
 Materials and processes used in crown- and 
 bridge- work, 247 
 
 molds and dies, 253 
 
 porcelain teeth, 252 
 
 soldering, 255 
 Melotte's method. 208 
 Metallic dies and counter-dies. 253 
 Metallic dies for forming caps with cusps 
 
 for crowns. 92 
 Models for bridge-work, 140 
 Molding, methods and materials used in 
 
 90. 99. 103 
 Molds and dies, 253 
 Morrison's crown, 79 
 Mouth, preparation of, 21 
 
 Necks of teeth, average forms of. SO. 221 
 New Richmond crown, 66 
 
 Objections urged against bridge-work, 135 
 
 against collar crowns, 98 
 Ottolengui root-reamers and facers, 63 
 Oxyphosphate cement. 128 
 
 Parr's crown. 117 
 
 Parr's detachable and removable bridge- 
 work. 183 
 Partial crowns, gold. 124 
 
 Dr. Littig's method, 127 
 
 ])orcelain, 126 
 Patrick's cap-stam])ing machine, 106 
 Pin-bridge, partial cap and, 212 
 Plaster impression and articulation, method 
 
 of taking, 140 
 Plate and solders, 249 
 Platinum plate, 249 
 
 wire, 249 
 
 with gold, 249 
 Pliers for shaping collars. 80. 225 
 
262 
 
 INDEX. 
 
 Porcelain iml gold crown without a collar, 
 
 77 
 Porcelain bridge-work, 23S 
 Porcelain crown with gold collar attach- 
 ment. 70 
 Porcelain crown with rubber or vulcanite 
 
 attachment, 76 
 Porcelain crowns, remarks on the use of, 69 
 Porcelain faces for crowns, 140, 160 
 Porcelain teeth, selection of, 252 
 
 some causes of fracture in soldering, 
 252 
 Pouring fusible alloy or metal, manner of, 
 
 99 
 Preparation, special, of badly decayed teeth 
 
 and roots, 39 
 Pulp, diseases of, requiring extirpation, 24 
 instantaneous devitalization, with ex- 
 cision of crown, 25 
 preservation or devitalization, 23 
 Pulpless teeth, their treatment and disin- 
 fection, 29 
 Punch forceps for riveting, for use in re- 
 pairing bridge-work, 170 
 
 Removable or detachable bridge-work, 172, 
 233 
 
 Dr. Litch's, 174 
 
 Dr. Parr's, 183, 184 
 
 Dr. Richmond's, 182 
 
 Dr. Starr's, 177 
 
 Dr. Waters's, 1 82 . 
 
 Dr. Winder's, 172 
 
 methods of forming attachments for, 185 
 Removable plate bridges, 187 
 Removal of crown- and bridge-work, 171 
 Repair of crown- or bridge-work, 170 
 Retaining-pin for all-gold crown. 111, 1 12 
 Richmond crown, 84 
 
 Root-canal, antiseptic agents for treatment 
 of, 31 
 
 dryer, 31 
 
 method of filling, 31, 32 
 
 method of treatment, 29 
 Root-reamers and facers, Ottolengui's, 63 
 Root-trimmers, Starr's, 179 
 Roots intervening between abutments, 150 
 Roots, special preparation of badly decayed, 
 
 39 
 Rubber or vulcanite attaohrai'-nt for crown, 
 76 
 
 Rules governing the insertion of bridge- 
 work, 137 
 
 Seamless gold collars, 222 
 Seamless gold crowns, 99 
 
 method of contouring, 105 
 
 method of forming from an impression, 
 102 
 
 process of adjustment and insertion, 
 108 
 Screws for use in crown-work, 52, 59 
 Sectional crowns, 84, 106 
 Sections of bridge-work, construction of 
 
 144, 147, 149,174 
 Self-cleansing spaces, 141 
 Shaping teeth and roots for crowning, pro- 
 cess of, 37 
 Shell anchorage or crown, 151 
 
 seamless, 153 
 Shoulders on the anterior teeth, 148 
 Slots for anchorage bars, 139, 149, 239 
 Solder, gold, formulas for, 250 
 
 Dr. Dorrance's, 250 
 
 Dr. Litch's, 251 
 
 Dr. Low's, 251 
 
 Dr. Richmond's, 251 
 Soldering, manner of, 144, 255 
 Solid gold crowns, 148 
 
 Special forms and methods in crown- and 
 bridge-work, 117 
 
 Dr. Knapp's, 203 
 
 Dr. Low's, 119, 199 
 
 Dr. Melotte's, 208 
 
 mandrel system, 221 
 Special preparation of badly decayed teeth 
 
 or roots, 39 
 Spur support in bridge-work, 158 
 Stamping press for caps, 106 
 Starr's method of detachable bridge-work^ 
 177 
 
 root-trimmers, 179 
 Strengthening gold seamless crowns, 110 
 Syringes, hot-air, 30 
 
 abscess, 34 
 
 Table of fusible alloys, 253 
 
 Teeth, porcelain, 252 
 
 Temporary attachment of bridge-work, 130 
 
 Thickness of ])late suitable for crown-work 
 
 80, 249 
 Tin, alloys of, 253 
 
INDEX. 263 
 
 Treatment of clironic alveolar abscess, 33 Weston's crown. 73 
 
 preparatory, of the mouth, 21 Winder's detachable bridge-work, 172 
 
 Trying in bridge-work. 141 Wire for posts or i)ivots, 85,249 
 
 Warping of bridge-work in soldering, 145 Zinc, oxy])hosphate of, for cemonting. 128 
 
 \Vaters's removable bridge- work. 182 
 
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