Columbia 59nttJer^ftj) intljeCttpofllfttigcrk College o! ^fipsiidans anti ^urgeong ILibrarp Digitized by the Internet Archive in 2010 with funding from Open Knowledge Commons http://www.archive.org/details/practicaltreatis1900evan :/ y^^ 16^ /f^ 2V -x A PRACTICAL TREATISE Artificial Crown- and Bridge- Work PORCELAIN DENTAL ART. BY GEORGE EYAIvTS, LECTUEBE ON CROWN- AND BRIDGE-WORK IN THE BALTIMORE COLLEGE OF DENTAL SURGERY : CLINICAL LECTURER IN THE NEW YORK COLLEGE OP DENTISTRY; MEMBEE OF THE NATIONAL DENTAL ASSOCIATION ; OF THE SOUTHERN BRANCH OF THE NATIONAL DENTAL ASSOCIATION ; OF THE DENTAL SOCIETY OF THE STATE OF NEW YORK ; OP THE FIRST DISTRICT DENTAL SOCIETY OF THE STATE OP NEW YORK ; OP THE NEW YORK ODONTOLOGICAL SOCIETY; HONORARY MEMBER OP THE MARY- LAND STATE DENTAL ASSOCIATION, ETC. Sixth Edition, Revised. WITH 6S1 ILLUSTRATIONS. PHILADELPHIA: THE S. S. WHITE DENTAL MFG. CO. 1900. iqoo. Copyright, 1888, by George Evans. Copyright, 1889, by G-eoege Evans. Copyright, 1893, by George Evans. Copyright, 1893, by George Evans. Copyright, 1896, by George Evans. Copyright, 1 900, by George Evans. HE PATTERSON AND ' To the Members of the First ^District (Dental Society of the State of J^ew York^ this (Book is respectfully dedicated by Tee piETEDR. PREFACE TO SIXTH EDITION. Twelve years have elapsed since the first edition of this book V7as presented to the dental profession. During that time several successive revisions have been made to better adapt it to meet the requirements of a practical treatise for college and post-graduate study, and of a book of reference for the practitioner. The en- deavor has been at all times to make the text comprehensive with- out being bulky, and concise without sacrificing cl earner for brevity. Descriptions of rarely practiced or unimportant methods have been curtailed from time to time, obsolete matter omitted, and repetition avoided as much as possible. Practitioners of to-day seek methods which mil permit the at- tainment of the desired results in crown- and bridge-work without the devitalization of pulps, with the least possible mutilation of the natural teeth, and the smallest exposure of metal, and which are least complex in construction. These ideas have largel}^ influenced the conduct of the revision of this edition. Many changes have been made in the text by the elimination of old matter and the introduction of new in the description of methods and details of construction. Some spe^ cial methods of little general service in crown- and bridge-work are still presented because they may occasionally furnish suggestions for construction by which some existing obstacle or difficulty can be readily overcome. Crown- and bridge-work, having been fully recognized as a legit- imate branch of dental prosthesis, is listed as a special branch in the Vi PREFA CE. curriculum of every dental college. In application it approaches a fine art. In no branch of dentistry will lack of knowledge and skill or the exhibition of carelessness in constructive details be more plainly evidenced, or result in greater proportionate injury instead of benefit. Criticism of failures should therefore be gov- erned by these considerations. Many failures are to be attribiited to attempts to perform bridge-work operations with about the same expenditure of time on 'the part of the dentist and money on the part of the patient as in plate-work. There is no such rela- tion between these two methods of procedure. The advances in porcelain inlays and porcelain bridge-work have been so conspicuous during the past year or two that it has been deemed desirable, in order that they might be properly pre- sented, to give them a distinct classification under the title, "Por- celain Dental Art." Acknowledgment is specially made by the author to Dr. F. J. Capon, of Toronto, Canada, for suggestions on porcelain crown- work, personally given; to the writings of Dr. C. L. Alexander, of Charlotte, N^. C, on crown- and bridge-work, in the Dental Cosmos; to Dr. W. H. Taggart and Dr. H. J. Goslee, of Chicago, papers and discussions on porcelain bridge-work in the Dental Review; to Dr. J. L. Williams, of London, Eng., and Dr. Joseph Head, of Philadelphia, writings on porcelain inlays in the Dental Cosmos; to Dr. W. A. Capon, of Philadelphia, for suggestions personally given and writings on porcelain dental art; Dr. 'N. S, Jenkins, of Dresden, Germany, for personal suggestions and writ- ings on porcelain inlays. Geoege Evans. 65 West 39th St., New York. August 27, ] 900. CONTENTS. PAGE Introduction 1 Artificial Crown- and Bridge-Work 5 PAET I. PREPARA.TORr TREATMENT OF TEETH AND ROOTS FOR CROWN-WORK. CHAPTER I. The Pulps of Teeth — Their Preservation or Devitalization — Pulp- Capping , 10 CHAPTER II. Devitalization of the Pulp 15 CHAPTER III. PuLPLESs Teeth — Preparation of Root-Canals — Their Treatment, Disinfection, and Filling 19 CHAPTER IV. Chronic Alveolar Abscess 30 CHAPTER V. Shaping Teeth and Roots for Crown-Work 35 PART II. ARTIFICIAL CROWN-WORK. the porcelain system. CHAPTER I. Porcelain Crowns 44 The Gates-Bonwill Crown 45 The Poster Crown 49 The Howland-Perry Crown 49 The Logan Crown 50 Remarks on the Use of P.jrcslain Crowns and Crowns without Cellars... 57 vii ^jlj CONTENTS. CHAPTER II. PAGE Porcelain Crown with Gold Collar Attachment 58 Method of Mounting a Logan Crown with a Band and Cap 69 CHAPTER III. Porcelain Crowns with Rubber or Vulcanite Attachment 6& THE gold system. CHAPTER IV. Gold Collar Crowns 66 The Construction and Adaptation of Collars 66 Collar Crowns Hygienically Considered TS CHAPTER V. Gold Collar Crowns with Porcelain Fronts 74 Incisors and Cuspids 74 Bicuspids and Molars 78' CHAPTER VI. All-Gold Collar Crowns for Bicuspids and Molars constructed IN Sections 8S CHAPTER VII. The Gold Seamless Cap-Crown 93 Incisors, Cuspids, and Bicuspids, with Porcelain Fronts 93 Ail-Gold Seamless Bicuspids and Molars 95. CHAPTER VIII. Gold Seamless Contour Crowns 99 Adjustment of Seamless Contour Crowns 102 CHAPTER IX. Special Forms of Gold Crowns with Porcelain Fronts ill Porcelain and Gold Crown without a Collar, and Partial Collar Crowns. Ill Mounting the Porcelain Front II5 The Parr Crown Hg The Leech Crown jjir The Perry Crown Hg CONTENTS. ix CHAPTER X. PAGE Crowning Fractured Teeth and Roots — Crowning Molar Roots DECAYED APART AT BIFURCATION CROWNING IN CaSES OF IRREGU- LARITY 120 Longitudinal Fracture of the Crown and Root 120 Fracture of the Crown with Slanting Fracture of the Root 121 Perforation of a Side- Wall of a Root-canal or of the Dentin at the Bifurcation of the Roots 122 Crowning Molar Roots decayed apart at the Bifurcation 123 Dr. Farrar's Cantilever Crown 123 Methods of Crowning in Cases of Irregularity 124 CHAPTER XI. Partial Crowns 125 CHAPTER XII. Finishing and Polishing — Process of Cementation 133 Finishing and Polishing Crown- Work 133 Insertion and Cementation 133 Oxyphosphate of Zinc 133 Gutta-Percha 137 Amalgam 141 PAET III. BRIDGE-WORK. CHAPTER I. Construction of Bridge-Work 1-50 CHAPTER II. Special Processes and Appliances in Bridge- Work 163 CHAPTER III. Extension Bridges 172 CHAPTER IV. Bar Bridges 178 CHAPTER V. Partial Cap and Pin Bridge 183 CHAPTER VI. Removable and Replaceable Porcelain Fronts 186 ^ CONTENTS. CHAPTER VII. PAGE General Application or Crown- and Bridge-Work 189 Extensive Applications of Crown- and Bridge-Work 200 CHAPTER VIII. 208 Repair of Crown- or Bridge-Work CHAPTER IX. The Hygienic Condition of the Mouth as affected by Bridge-Work 214 CHAPTER X. Removable and Detachable Bridge-Work 216 Removable Incisor or Cuspid Crown Removable Bicuspid and Molar Attachments CHAPTER XI. 234 Removable Plate Bridges CHAPTER XII. Special Forms of Detachable and Removable Bridge-Work 246 Dr. Winder's Sectional Crown Method Dr. Litch's Method Dr. R. W. Starr's Methods ^^^ Dr. Parr's Methods ^gg Dr. Waters's Methods Dr. Bonwill's Method CHAPTER XIII. „ ^ -269 Removable Bar-Bridges CHAPTER XIV. 275 Dr. Knapp's Methods CHAPTER XV. 280 The Mandrel System CHAPTER XVI. 287 The HoLLiNGSwoRTH System To Make a Gold Crown (Bicuspid or Molar) ^»^ To Make Solid Gold Cusps •• To Make Gold Crowns (Centrals, Laterals, and Cuspids) ^^J To Insert a Porcelain Facing ;•; To Make the Grinding-Surface of a Bridge in One Continuous Piece 294 Facings for Making All-Gold Bridge '^ CHAPTER XVII. Crown- and Bridge-Work combined with Operative Dentistry in ^^^ Dental Prosthesis CONTENTS. xi PAET IV. PORCELAIN DENTAL ART. CHAPTER I. PAGE Porcelain Inlays 310 Preparation of Cavities 311 To Form the Matrix 314 Investing the Matrix 317 Selecting the Color of the Porcelain Body 318 Dr. Jenlcins's Low-Fusing Porcelain 319 High-Fusing Porcelain 321 Removing the Foil Matrix 321 Cementation 322 Points to Bear in Mind 322 Porcelain Tips 325 CHAPTER II. Porcelain and Platinum Crowns 327 Porcelain Inlaying of Gold Crowns 331 Respective Merits of Various Grades of Porcelain 333 CHAPTER III. Porcelain Bridge-Work 335 Platinum Solder 341 Furnaces for High-Fusing Porcelain 342 PAET V. MATERIALS AND PROCESSES USED IN CROWN- AND BRIDGE-WORK. CHAPTER I. Plates and Solders 347 CHAPTER II. Porcelain Teeth 351 CHAPTER III. Molds and Dies 362 How to Quickly Make a Tube and Fusible Metal Die 352 CHAPTER ly. Soldering 354 CHAPTER V. Instruments and Appliances 357 Index , 361 INTEODUOTIOISr TO FIRST EDITIOK Of the origin of the art of dentistry no one can speak with certainty, as its early history is shrouded in the mists of antiquity ; but dental operations are recorded in very remote times. References are made to the art in the writings of Hippocrates, in the fifth century b.c. Martial, the Latin poet, in the first century b.c, says that a Roman dentist "Cascellius is in 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 that "the toothless mouth of Egle was repaired mth bone 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." Gralen, 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 offend- ing teeth and the replacement of those which had been lost with fc^ubstitutes which were retained in position by means of narrow bands or ligatures attaching them to the adjoining natural teeth, ji.nd without the use of plates. Crude as they were, they formed the first expression of the art of dentistry, a beneficent art from the beginning, in that it sought to remedy pathological or acciden- tal defects. Confined to the simplest operations, it existed for centuries, and then was apparently lost during the Dark Ages, to reappear when the more general diffusion of knowledge ushered in the modern era of science and invention. After its revival, dentistry, so much of it as was known, was in a measure a secret art, the practice of which even within the memory of men now living, and they not the oldest, was involved 2 1 2 INTRODUCTION TO FIRST EDITION. in mystery; but recent progress. has lifted the veil, and dentistry, in the treatment of the teeth on correct, scientific, rational prin- ciples, has developed an art and a science which have given it honorable rank among the professions. In its twofold evolution it has absorbed from every available source whatever would broaden its science or perfect its art. It calls to its aid anatomy, physiology, pathology, chemistry, therapeutics, metallurgy, sculp- ture, and mechanics, with each of which it stands in closer or more remote relation; and the practitioners of dentistry who have be- come the most eminent and useful have been men of broad attain- ments and great versatility of talent. In the history of all progress, movements apparently of a more or less reactionary character are recorded. In the useful arts especially it is not uncommon to find a return to forms and methods form.erly used, but long since discarded and forgotten. So in dentistry we find methods of treatment and modes of practice once in vogue but long fallen into disuse, revived with improve- ments and modifications that stamp them as practically redis- coveries. These movements are not to be regarded as retrogressive, because the modifications which accompany the reintroduction of practical ideas and inventions attest them as real advances, and indicate clearly that the cycle of knowledge is ever widening with experience. This volume demonstrates how modern dentistry has utilized the principles of some of the simplest original opera- tions, and by "proving all things, holding fast that which is good.'^ has attained its present honorable position in both its scientific and artistic departments. The history of dentistry of later years is, in brief, a recital of progress and improvement. The medical profession has officially recognized it as closely allied to medicine by inviting its represen- tatives to take part in the International Medical Congresses 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 IJSTROVUCTION TO FIRST EDITION. 3 lias been 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 by the success- ful 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 uplift- ing and upholding of dentistry by the mutual helpfulness of its practitioners 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 professions. ARTIFICIAL CROWN- AND BRIDGE-\YORK. Modern artificial crown- and bridge-work belongs to the department of dentistry formerly termed "mechanical;" but the judgment, skill, and scientific information required place it far above ordinary mechanical dentistry, 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 divest it, in the hands of those who depend upon vulcanite, 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 offers wide scope for versatiHty of tale^it and inventive genius. The varied and complicated cases presenting for treatment frequently suggest to the expert novel contrivances and methods of construction 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 judg- ment 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 statement of the applicability of the system to his case, in respect to usefulness, appearance, durability, and comfort, as compared with other pro- cesses and appliances in use. Surgical and mechanical operations of the most delicate nature are required. ISTothing, indeed, in dentistry demands finer manipulation. A practical consideration of the subject will show that a knowledge of anatomy, pathology, and therapeutics, and 5 6 ARTIFICIAL CROWN- AND BRIDGE-WORK. ae well mechanical and artistic skill, are necessary to tlie 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 restoration of the articulation and the anatomical contour; and, in bridge- work, the selection of suitable teeth or roots for foundation piers or abutments, and the choice and adaptation in constructive prac- tice 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 princi- ])les gives results which have gradually established its value, re- moving erroneous impressions and insuring a wide professional and public indorsement of this important branch of prosthetic dentistry. Its extraordinary facilities for preserving and replac- ing teeth have made for it the position in dental art which it m.erits. PART I. PREPARATORY TREATMENT OF TEETH AND ROOTS FOR CROWN-WORK. PEEPAKATORY TREATMENT OF TEETH AND ROOTS FOR CROWN-WORK. Prepakatoey 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 i-ecurrence 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 applica- tion of crovm- or bridge-work. Roots which are permeated and softened by decay, exposed or loosened from absorption of the gums and alveoli, or affected with irremediable disease of the investing membranes, should be thus classed. Cases in which abscess with necrosis has extensively 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. CHAP TEE L THE PULPS OF TEETH— THEIK PEESEKVATION OR DEVITALI- ZATION— PULP-CAPPING. The preservation of the vitality of the pulps of the teeth is a matter of as much importance in connection with crovi^n- and bridge- work as in any other class of operations, though the excision of natural crowns for the purpose of utilizing the roots as abut- ments for bridge-work is extensively practiced, and is defended by some on the theory that the vitality of the dentin is to some extent maintained by the cementum after the extirpation of the pulp, and by others on the plea that in a fully developed tooth the pulp, being the formative organ, is of no further value when root- canal treatment is properly conducted. The pulp after going through progressive changes which consti- tute its original function assumes a fixed anatomical character. It becomes the source of the vascular and nervous supply, from which the dentin derives and maintains its vitality. The proto- plasmic bodies of the pulp unite with the living matter of the tubuli, which anastomose to a limited extent with those of the cementum through the intervening protoplasmic bodies in the interzonal layer. This distribution and relative connection of living matter as described refers to an existing state of perfect vitality of all the parts. When the pulp loses its vitality, an entirely different condition results. The tubuli are then deprived of vital circula- tion, except along the line of the outer portion of the dentin, where, in the interzonal layer, the fibrillse anastomose vsdth the living matter of the cementum. The vitality supported by this anastomosis is almost entirely confined to this part, the nutrient supply being insufficient to assume the functions of the pulp and maintain circulation in the main body of the dentin. (See Plates I, II, III.)i opiate I. — Longitudinal section of the root of a superior bicuspid, at junction of dentin with cementuni. C, cementum; D, dentin; I, intei-zonal layer; L, lacunse of cementum. X 175. 10 Platk I. Plate II. Nf'*v,:> , :•»» » Plate III. Fk(jm .Specimens mai>e by M. H. Fletcher, M. D., Dentist. Cincinnati, Ohio. E. MOEBfUS, CAMDEN, N. J. THE I'ULFS OF TEETH. 11 Cliemical analysis of the dentin shows that the organic matter, consisting principally of the fibrillse, exists in the proportion of nearly 25 per cent, to 64 per cent, of lime-salts.^ When the pulp has been removed, the devitalized fibrillse still remain, and, unless antiseptic root-canal treatment has been thor- oughly carried out, they are capable of generating septic gases which will exert an influence in producing irritation of the cemen- tum and pericementum. An examination of the investing mem- branes of pulpless teeth as treated generally shows the existence of a percentage of abnormal conditions, by which their firmness is to some extent impaired, their susceptibility to acute inflammation in- creased, and their reliability as foundations for crown- or bridge- work greatly lessened when compared with teeth which have living pulps. Observation of gold-capped pulpless natural crowns of teeth also has shown the author that the dentin of such teeth in the course of years gradually softens to such an extent as to impair their strength. In cap-crown work, facilities are afforded for the preservation of pulps in the posterior teeth. Thus, in a case vergiiig on ex- posure, only partial removal of the decay is usually necessary, as, when the operation is completed, the natural crown will be hermetically inclosed by the artificial one. In bridge-work, proper methods of practice in a large percentage of cases will also permit the anterior teeth to be used as abutments without the extirpation of their pulps or the excision of their crowns. Extirpation is demanded for those pulps whose permanent preservation cannot be placed beyond donbt, as failure involves Plate II. — A field taken from Plate I in position marked A. L, lacunae of cementum ; C, canaliculi of dentin; I, interzonal layer. X 210. Plate III. — A field taken from Plate I in position marked B. L, L, L, lacunae of cementum ; I, interzonal layer; D, dentinal tubes and their nearest approach to the lacunae. X 210. A study of these plates demonstrates the limited nature of the anastomosis of the fibers of living matter of the dentin and cementum. ' The analysis of dentin by Dr. G. V. Black gives an average of — Lime-salts . . . . . . . . . . . .63.54 Organic matter . . . . . . . . . . .25.36 Water 11.06 Age slightly lessens' the proportion of living matter and increases the percent- age of lime-salts. 12 ARTIFICIAL CROWN- AND BRIDGE-WORK. more serious consequences in crown- and bridge-work tlian in filling-operations. The lesions of the pulp which seem to require its extirpation, according to the generally expressed opinion on the subject, are exposure mth hypertrophy or rupture of the pulp- sac, congestion, and pulpitis which does not yield promptly to remedial treatment. Pulps actually exposed by decay are seldom found in a normal condition otherwise, and they are only rarely proper or hopeful subjects for remedial treatment. Atrophy of the membrano. ehoris, or investing membrane, which comprises the layer of odontoblasts, usually exists at the part exposed, and, as any subsequent calcification must depend on the activity of the odontoblasts, it is evident that the existence of the condition referred to affords a strong argument against the advisability of capping pulps in cases of extensive or even slight exposure. The difiiculty of securing a condition of asepsis of the exposed and diseased parts so perfect as to assure them against the invasion of micro-organisms subsequent to capping is an additional argu- ment against the operation. Pulps which are in a normal condition, still protected by a layer of even decomposed or partly decomposed dentin, usually admit of successful treatment. In such cases the decayed dentin may be excavated from the side walls of the cavity, but that in the region of the pulp should be only superficially removed; in some cases this portion may be allowed to remain undisturbed. Pulp-Capping. — The operation of capping a pulp should in- clude, as a necessary precaution against subsequent irritation, the thorough disinfection of any remaining decomposed dentin. An excellent method of disinfection is to first thoroughly wash the cavity several times with tepid water thrown gently from the large point of a syringe around the sides of the cavity ; then, taking measures to prevent the entrance of saliva, wipe the cavity with absorbent cotton and pass over its surface a light current of hot air from a hot-air syringe. The heat should be sufiicient to cause some discomfort to the patient, but not enough to produce irrita- tion of the pulp. The dried cavity is then immediately saturated with carbolic acid previously warmed-^ to the normal temperature 1 Thermal shock to the pulp is as unwarranted from the application of cold carbolic acid as if produced in any other manner. THE I' LLPS OF TEETH. I3 of the body by holding the pellet of cotton on which it is applied over the flame of a lamp for a moment. The carbolic acid relieves any pain caused by the evaporation of moisture, and disinfects and sterilizes any decomposed matter in proximity to the pulp. The object of the application of the carbolic acid having been accomplished, the surplus may then be removed from the sur- face. To this end the cavity should first be wiped with absorbent cotton, and hot air again introduced to evaporate the carbolic acid sufficiently to give a dry appearance to the surface. This second application of hot air, owing to the effect of the drug, will cause very little or no pain. This method, if practiced early in the preparation of the cavity, will be found to considerably obtund sensation, and, through the dryness secured, to materially facilitate the removal of the decom- j)osed dentin. A reasonable amount of the decayed portion should be cut away, as it lessens the difficulty of proper disinfec- tion. For excavating in the region of the pulp-chamber, spoon- shaped excavators should be used invariably. For the thorough disinfection of dentin and removal of hypersensitive conditions, the author practices the method of previously placing and sealing in the cavity for from two days to a week a mixture of precipitated chalk and carbolic acid and oil of cloves in equal parts. A small quantity of aristol may also be added. ^ The disinfected dentin over the pulp is then varnished with chloro-gutta-percha, or some other preparation suitable for the purpose, and capped with oxyphosphate or oxychlorid, as pre- ferred. When the capping is set, the remainder of the cavity is filled with the same cement as the capping, or with amalgam. Some preference is given to oxychlorid of zinc as a pulp- capping over the oxyphosphate, because of its antiseptic properties ; but its use invariably requires a thorough application of chloro- gutta-percha to thin areas of dentin over the pulp. Pulp-capping, when necessary, should precede any other opera- tion, and no subsequent procedure is admissible until the success of that operation is assured, the time allowed for this purpose 'The chalk is placed in a mortar, and the carbolic acid and oil of cloves grad- ually introduced and thoroughly incorporated with the chalk by trituration until the mixture becomes a plastic mass. 14 ARTIFICIAL CROWN- AND BRIDGE-WORK. being governed by the requirements of each case. A non-vital condition of the pulp in one root of a tooth contraindicates any attempt to preserve it in any of the other roots, in connection vs^ith crown- and bridge-work. The rubber-dam, when its use is practi- cable, will be found a material aid in difficult pulp-capping operations. CHAPTEK II. DEVITALIZATION OF THE PULP. In preparation for crown-work two methods of devitalization are practiced: the heroic, — instantaneous devitalization, or extir- pation, — and gradual devitalization by arsenical treatment. Instantaneous devitalization can be accomplished by fii-st ad- ministering to the patient sufficient nitrous oxid to produce partial anesthesia, then with a drill quickly opening into the pulp- chamber, and lacerating the pulp well up the canal with a probe or smooth broach. Instantly afterward a pellet of cotton, satu- rated with carbolic acid, is forced up the canal, and, if possible,^ left until the next day, when the pulp will be found in a coagu- lated mass that is easily removed entire. Devitalization of the pulp as just described is practicable only in teeth in normal condition. In acute inflammation, after lacera- tion of the pulp, warm water should be gently injected into the pulp-chamber, and sedative agents then applied. Subsequent treatment should be such as will complete the devitaKzation and extirpation of the pulp. Cataphoresis. — ^In cases of actual exposure of the pulp the rubber-dam can be applied, the exposed pulp obtunded with hydrochlorate of cocain, applied ^^"- ^• in saturated solution; the diffusion may be hastened with electrolysis. As soon as the action of the cocain is manifest, the pulp may be extirpated. Excision of the crown and instantaneous ex- \ \ ^ tirpation of the pulp is practiced as follows: Two parallel grooves are cut opposite to each other, through the enamel, deep into the dentin, one on the labial portion of the tooth and the other on the palatal w-all, close to the gum, with a rapidly revolving corundum or rubber and corundum disk (Fig. 1). Then with excising forceps,. 16 16 ARTIFICIAL CROWN- AND BRIDGE-WORK. the cutting-edges of whicli are inserted in tliese grooves, the crown is qnicklj severed from the root (Fig. 2). The pnlp either adheres to the excised crown, leaving the canal empty, or remains in the root, fully exposed. In the latter case, a pointed piece of orange- wood, previously cut to fit the canal, and saturated with carbolic acid, is quickly driven with a blow into the pulp toward the apex of the root (Fig. 3). When the wood is withdrawn, the pulp usually adheres to it; if not, the wood is instantly reinserted, cut Fig. 2. off and drilled out with the pulp, using Gates- Glidden drills in the upper portion of the canal. In this operation only trifling pain is experienced by the patient, as the pulp is paralyzed by shock in the excision of the crown, or by being forced upward toward the foramen and against the walls of Fig. 3. the canal. The objections to this opera- tion are, that if the pulp is not successfully extracted entire with the wood the canal be- comes filled with clotted blood, which is difficult to remove from the extreme end; also that the U root and socket are jarred by the forceps in excising the crown; but, expertly performed, it is advantageous in many cases, though it should be confined to cases where the pulps are in normal condition. In cases of actual exposure in which excision of the crown cannot be safely practiced, as, for instance, in a bicuspid, a por- tion of the walls and grinding-surface may be removed to the line of the root-canal, the palp obtunded with carbolic acid, and the wood point then forced up the root-canal in the same manner as in excising the crown. Devitalization with Arsenious Acid. — The methods of devital- izing previously described are applicable principally to the pulps of incisors and cuspids. In the posterior teeth, which do not so well permit the heroic treatment, recourse is had to arsenious acid, notwithstanding the numerous objections to its use. Two theories as to the mode of its action in devitalizing are widely DEVITALIZATION OF THE PULP. 17 entertained: First, that i1s toxic effects produce hyperemia, which stops circulation; the other is thrombosis.-^ This theory of thrombosis might account for the gradual devital- ization of the pulp toward the foramen. Whatever the action of arsenic on the pulp may be, it always causes an infiltration of the tubuli of the dentin with certain constituents of the blood, probably the liquor sanguinis. The residue of the infiltration, after the devitalization of the pulp, to some extent remains in the tubuli, and increases the difficulty of producing an aseptic condition of the dentin. It is asserted that in some cases arsenic affects the vitality of the cementum, while after instantaneous extirpation of the pulp, when arsenic is not used, vitality is assured. Practical experience shows that usually instant devitalization 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. In cases of non-exposure, requiring its application, a small opening into the pulp-chamber should be made. This can be accomplished with but little pain to the patient with a very small, sharp, spear-headed drill, rapidly revolved by the engine. The drill should be held steadily under gentle pressure at one point in the line of the intended exposure, until the pulp is slowly and gradually reached, and not suddenly punctured with the drill- point. The drill should be occasionally removed and the cavity flooded wdth carbolic acid during the operation. Cataphoresis may also be practiced. The use of arsenic, combined with agents which are non- coagulants of albumen, is recommended in preference to combin- ing it with creasote or carbolic acid. Dr. Harlan's method is to apply an anodyne, such as wine of opium, for a minute or two, and then the following paste : R — Arsenious acid, gi ; Muriate of cocain, ^ii; Lanolin in quantity sufficient to make a stiff paste. The application should be kept in position no longer than is ^See Dr. L. C. Ingersoll's "Dental Science, Questions and Answers," page 96. 8 18 ARTIFICIAL CROWN- AND BRIDGE-WORK. necessary to effect the devitalization of the pulp, twelve to forty- eight hours being sufficient for the purpose. The pulp is then punctured, a saturated solution of tannin in glycerin applied and securely sealed in the cavity, and the patient dismissed for several days. At the end of that time, in favorable cases, the pulp can be removed entire. The saliva should be entirely excluded, the rubber-dam being applied when practical, and peroxid of hydrogen or absolute alcohol, instead of water, used in the treatment.-^ When creasote or carbolic acid is used in combination with arsenic, the same method of subsequent treatment may be practiced. When the position of the tooth or root makes the application of the rubber-dam extremely difficult or impracticable, the operation can be successfully conducted without its aid in this way: At short intervals during operative proceduies, at each sitting of the patient, thoroughly syringe the pulp-cavity with peroxid of hydrogen, preventing the entrance of the saliva by at once insert- ing a pellet of cotton saturated with the peroxid, oil of cloves, or some other antiseptic. The tooth can then be protected from the saliva by any of the usual methods practiced, and the treatment proceeded with. ^ See Denial Cosmos, vol. xxxiii, page 138. CHAPTEK III. Fig. 4. PULPLESS TEETH— PKEPAKATION OF ROOT-CANALS— THEIR TREATMENT, DISINFECTION, AND FILLING. The treatment of piilpless teeth or roots consists in as thorough s performance as possible of the following operations: First. Removal of the contents of the canals. Second. Disinfection of the root-canals and the dentin, and the establishment of permanent aseptic conditions by mummification of the contents of the tubuli. Third. Closure of the apical foramen. Pre'paration of Root-Canals. — A knowledge of the usual posi- tions of the root-canals in the different teeth is essential for a gener- ally successful performance of this operation, which is greatly facilitated by the ease with which direct access to the root-canals is obtained in cro^vn-work. (See Plate IV.)^ In the anterior teeth, the removal of the coronal section directly exposes the pulp-chamber. In bicuspids and molars, for all- gold crowns, the leveling of the occluding surface (see Fig. 4) and removal of a portion of the side most involved by decay should be preliminary. An opening is first made into the center of the pulp-chamber in a line with the root-canals suffi- cient to give free and direct access to them, and any remaining portion of the pulp is removed mth broaches. A few fibers of cotton twisted around the serrated por- tions of the broach will admit of its easy removal in case of 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 en- trance 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, hb, cc, dd, ff, 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 represent. 19 Sectional view of an inferior molar decayed on the pos- terior approximal side. A, the line to which the crown should be removed to facilitate en- trance to the pulp- chamber. Plate IV. ,^ /f^ '%\oy I i i 5^ ""S^e^ TREATMENT OF PULPLESS TEETH. 21 Fig. 5. breakage. The canals arc tlieii, guided by frequent explorations with a fine probe, carefidly enlarged with Gates-Glidden drills (Fig. 5). At least three sizes — large, medium, and small — of drills each for the right-angle and the direct hand-piece are re- quired. Very little, if any, 'pressure should be put upon them when in motion, as they will move forward of themselves. Under pressure the formation of a false passage in a curved root is possible, or the small drill might be broken off or forced through the apical foramen with disastrous consequences, where alveolar abscess did not exist. ISTeither should drills be forced into canals closed by calcifica- tion, nor beyond the line of the zone of cementum at the end of the root, nor through a constriction which a fine, flexible probe cannot enter, nor around a curve sharp enough to be unsafe to pass. A slight pain is usually experienced when they enter the zone of sensibility formed by the cementum which composes the end of the root, of the slightest symptom of which the patient should be instructed to instantly inform the operator. The probe-like points of these drills do not cut, but simply guide the drills and confine them to the line of the canal. They should be gently given a slight for- ward and backward motion in the canal, and treated more as reamers than drills. The occasional quick withdrawal of the drill from the canal during the process of drilling will aid removal of the debris. The depth to which a canal may be enlarged or reamed is regulated by its actual length and the above-mentioned conditions, and the diameter of the enlargement by the shape and dimensions of the root. The use of these drills is condemned by some for reasons attributable to their careless or improper employ- ment, but they are indorsed, in experienced hands, for their adaptability to the work under consideration. They should be frequently sharpened with a suitably shaped piece of Arkansas stone. The Palmer root-canal excavators also will be found serviceable to open up a canal and enlarge it in accordance with its original shape. Donaldson pulp-canal instruments are also useful in the upper portion of canals or in those of very small caliljer. A fifty per cent, aqueous solution of sulfuric acid 22 ARTIFICIAL CROWN- AND BRIDGE-WORK. pumped into the orifices of root-canals with cotton wound on a broach is most effective as an aid in opening up very small canals or those partly closed by calcification. In the former case the acid softens the dentin of the sides of the canal so that the friction of a smooth broach will materially enlarge it; in the latter, in addition to this effect, it decomposes the calcified contents of the canal. This enlargement of the canal with the smooth broach will usually admit the introduction of a Donaldson barbed broach, by which the canal can be much more rapidly enlarged. Canals by this method can almost invariably be safely opened and enlarged to the apex. The moderate reaming of a root-canal not only simplifies the operation of filling, but also opens up the ends of the tubuli and facilitates the permeation of antiseptic agents. Treatment and Disinfection. — Pulpless teeth are presented for treatment in one of the four following conditions: 1. Where a healthy or non-putrescent pulp has just been extir- pated from the canals. 2. Where on opening into the pulp-chamber it is found empty and dry, with the pulp mummified or calcified in the root-canals, and the root externally in a healthy condition. 3. Where the pulp is found diseased or in a putrescent condi- tion. 4. Where alveolar abscess is present and a septic condition of the canals and dentin exists. In the first and second classes the treatment should be directed to assuring a continuance of the existing aseptic condition, and as immediately as possible the filling of the canal; in the third and f ourtli classes, to bringing about an aseptic condition by dis- infection and sterilization, and making certain of its future maim tenance, including incidentally the cure of any existing disease of the external membrane or of the alveolus. In cases of the first and second classes, if possible, saliva should be excluded from the pulp-chamber and canals during their entire preparation and filling. If necessary, peroxid of hydrogen can be used instead of water. The instruments should be sterilized, and the broaches, if serrated, had better be new. In the third and fourth classes, exclusion of saliva or water is not necessary in the preliminary work on the canal; water may be freely used until TREATMENT OF PULl'LESS TEETH. 23 the process of disinfection and sterilization is commenced. Then and thereafter its entrance must be prevented. To this end the rubber dam should be applied if practicable. When it is not, aai Fifi. 6. frequently occurs with roots and teeth badly affected with cervical decay, other means of keeping out moisture should be resorted to. In such cases, during each interruption in the operation the entrance to the canal should be filled with absorbent cotton saturated with a suitable essential oil or antiseptic fluid, the saliva being thus excluded. After the canal has been properly opened up and its contents removed, it may be washed out with peroxid of hydrogen, and wiped out with absorbent cotton. The use of sodium peroxid is Fig. 7. recommended by Dr. Kirk at this stage to open up the ends of the tubuli. The next point in the conduct of the operation is to secure as thorough a state of dryness in the pulp-chamber by 24 ARTIFICIAL CROWN- AND BRIDGE^WORK. an ordinary (Fig. 6) or an A. S. Eiclimond (Fig. 1) hot-air syringe, at a temperature higher — as it leaves the nozzle — than is com- fortable for the finger. A root-canal dryer, with the end tapered as fine as a broach at the point, is then introduced into the canal. The writer prefers the form in which the point is made of silver and the bulb portion of copper (Fig. 8). As silver possesses remarkable properties as a thermal conductor, the heat is trans- mitted to the point of the probe very rapidly. The probe being inserted as far as possible up the canal (Fig. 9), 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 Fig. 8. ^^^ ^ moment. This procedure, follow- Fig. 9. ing the previous application of the hot air with the syringe, evaporates the moisture and aids the escape of any i gases present in the root-canals and the open ends of the tubuli. The point of the root-canal dryer acts as a sterilizer, and may be applied so hot as to car- bonize any organic matter which it reaches in the end of the canal, and a portion of this can be removed each time on its point. As the silver point can be tapered as small as the finest broach, canal-contents impossible to re- move may be reached or rendered inert. In cases of the third or fourth class, sepsis being present, the heat is very serviceable, as it aids the escape of gases from the canal and dentin and acts as a germicide. When in this dry and heated condition, the dentin is in the best possible state for the application of antiseptic agents. Antiseptic Treatment. — The suitability of various antiseptics to the needs in treating tooth-structure, their effectiveness and per- manency when so used, singly or in combination, are subjects on which great diversity of opinion exists, and which have of late been made the object of clinical study and scientific investigation and discussion. Many antiseptics in common use being coagulantg of albumen obstruct the dentinal tubuli, and consequently limit TREATMENT OF Pl'LI'LESS TEETH. 25 or retard diffusibililj tliroiigliout the dentin. 'J'liis is tlie oljjoc- tion to the use of carbolic acid, creasote, and like agents, addi- tionally to which may he named their inefficiency to accomplish in certain conditions the end sought, and as well their eventual al)Sorption from the dentin. Recent in^'estigations seem to give preference to such antiseptics as are nou-coagulative in their action. Of this character are the essential oils, many of which according to Miller, Harlan, and others, possess antiseptic power much greater than has been commonly attributed to them. Acidulated solutions of bichlorid of mercury, peroxid of hydrogen, sodium peroxid, especially in preliminary treatment, and various preparations of iodin, which exert chemical action and retain their antiseptic properties for a great length of time. The selection of antiseptic agents is important, and is indicated by the conditions presented in a pulpless tooth. Cases in which a healthy pulp has just been extracted, or the canal is aseptic, are different from those with sepsis of dentin or diseased or putrescent pulps. In the first-mentioned condition, with or without antisep- tic treatment, favorable results usually follow root-filling, the advantage of a reliable antiseptic agent in the canal being only to better insure the continuance of a state of asepsis. In the second condition the state of the dentin, and consequently the treatment to be effected, are entirely different. We need the intervention of agents that will not only destroy ptomaines, but exert a chemi- cal action on sulfuretted hydrogen and ethereal ammoniacal gases, the products of putrefaction, and entirely eliminate them. On this depends the successful treatment of such cases, as the pressure and expansion of these gases are a certain cause for constant peri- dental inflammation, and so long as they are present in the slightest degree in a canal it is in an unsuitable condition to bo closed. Carbolic acid, creasote, or the essential oils, in such a condition exert no chemical action on these gases, merely disguis- ing their odor, though by repeated dressings of cotton saturated with one of these agents the gases are absorbed by the cotton, and to an extent slowly eliminated. What is required is the action of agents whose elements possess an affinity for the gases, and so will immediately decompose them, forming new combinations and entirely changing their character. In accordance with these principles, the use of iodin is indi- 26 ARTIFICIAL CROWN- AND BRIDGE-WORK. cated and preference is given to its use in, practice to that of the other agents mentioned. Its effects are best obtained from some one of the preparations now in nse, — aristol, for instance, wliose odor is entirely unobjectionable, in a strong solution in one of the essential oils. In the writer's practice he favors the oils of cloves, cassia, and eucalyptus, considering the oil of cloves more sedative in action than the others. He makes it a point to flood the canal with the solution, thereby to some extent saturating the heated dried dentin as well as the cementum at the apex. A more effective saturation can be accomplished by again drying and heating the dentin and applying the solution, or by filling the canal with cotton saturated with the solution, hermetically inclos- ing it and letting it so remain for a day or two. Coagulants, such as creasote or carbolic acid, are not entirely non-diffusible in devitalized dentin or cementum, as decomposi- tion or putrefaction effects elementary changes in the contents of the tubuli, but their action is slow and limited compared with that of the essential oils. They have also the objectionable feature of being irritants, and unsuitable where acute or chronic inflamma- tion of the peridental membranes is present. When a healthy pulp has just been extirpated, and immediate root-filling is prac- ticed, the use of carbolic acid, creasote, or solution of chlorid of zinc is best indicated, the condition then presented being entirely different from that where the pulp is diseased or putrescent, or the canal is in a septic state. When a healthy pulp has been re- moved, its minute fibrous connections with the walls of the canal and the vessels at the apical foramen are severed, and the action of an escharotic antiseptic agent, such as carbolic acid, is in fact then indicated, as it acts as a coagulant and instantly seals up the ends of the tubuli. If immediate root-filling is not to be practiced, then the prescription of such agents as the essential oils, with aristol or iodoform, seems more suitable, as by their action a sort of mummJfication of the non-vital organic matter follows. More- over, the oils possess advantages over the coagulants mentioned as they are not miscible in water, and are easily eliminated. Their use consequently will better tend to perpetuate an antiseptic condi- tion. The disadvantage of immediate root-filling is that, should some fragment of the pulp remain in the extremity of the canal, it fails TREATMENT OE EEL PI. ESS TEETH. 27 to receive the benefit accruing from the reapplication of antisep- tics, which would better assure inertness by mummification. There is such a thing as over-treatment, — an unnecessarily frequent renewal of antiseptic dressing in root-canals, thereby aggravating or producing irritation of the pericementum at the apex of the root. Such cases may be relieved by washing out the canal with alcohol and applying the alcohol on the dressing, instead of the agents previously employed. The dressing of root-canals is best performed with the aid of the ordinary smooth, flexible rectangular broaches; also root-canal dressers, such as the How. The form of these instruments permits fibers of cotton to be easily wound around them lengthwise and over the point in one connected mass. ^Vhen the cotton is intro- duced in the canal, it is retained on and carried forward by the in- strument, which, when withdrawn, leaves the cotton in position in the canal in the form of a cone or tampon that will favor the escape of gases, and it may still be easily removed at any time. After one or more treatments in the manner described, between which, if interspersed by intervals of time, the antiseptic agents must be hermetically sealed in the cavity with gutta-percha, the canal is dried and the foramen closed. Closure of the Apical Foramen and Filling of the Canal. — The object of root-canal filling is to prevent the entrance of the fluids through the foramen, and to avert, in case of the formation of gases, irritation of the peridental membranes by their pressure or presence. Gutta-percha and oxychlorid of zinc are generally accepted as most suitable for the purpose. Either gutta-percha in the form of chloro-gutta-percha, or the oxychlorid of zinc mixed thin, can be pumped or placed in the extreme end of the canal with the aid of a broach or fine-pointed probe. This is one of the advantages that commend the use of these materials. When the chloro-gutta-percha has been pla -i,, n^ . , fiU W> thc baud with Melotte's I :M 1. Socket. 2. Fusible Metal. y II ::m moldine or plaster, pressing it ll||_^___.--r^l^ closely about the peg. Remove all together, and ^te> 1^ hold the die over the flame of an alcohol lamp to ^- :^ melt the fusible metal. "When melted, place the K ^ socket side of the band or collar and wooden plug i# that enters the root-canal downward on the surface of the metal; cool and remove the moldine or plaster, and plug. This gives a tight grasp on the lower end of the band and does not allow it to change shape. While fitting the crown into it, place the crown in the band, allowing the pin to 58 PORCELAIN CROWN WITH GOLD COLLAR ATTACHMENT. 59 enter the socket. Drive clown with a mallet till the porcelain comes in contact with the metal. In this way you stretch the gold around the porcelain; now. burnish down' tightly. If this work is carefully done, the articulation should be the same as before the band was put on. Melt fusible metal to relieve the collar and crown. This method of setting a porcelain crown makes a strong operation. Enough of the collar should be trimmed away at the labial portion to prevent too conspicuous exposure of the gold (Fig. 83). This collar combination is available in very difficult cases, as, for instance, when a root is decayed upon one side far beneath the gum, as seen in Fig. 84. Fig. 83. Fig. 84. Fig. 85. Fig. 86. Such an operation, when completed, would appear in vertical section like Fig. 85, and a view in perspective would resemble Fig. 86. The collar is also very useful wherever the root and crovoi are not made flush and smooth at every point, as, if practi- cable, they should always be. METHOD OF MOUNTING A LOGAN CROWN WFTH A BAND AND CAP. Prepare the root in the usual way for banding. (See Fig. 87, front view, and Fig. 88, side view.) Grind the abutting surface of the crown to fit the root under the free margin of the gum, along the labial face only. (See Figs. 87, 88, a to I.) Cut the crown away slightly at the lingual surface, so as to leave a space between it and the end of the root. (See Fig. 89, c.) 60 ARTIFICIAL CROWN- AND BRIDGE-WORK. Make a band wide enough only to give a good hold on the root, but not to extend beyond the margin of the gum to fit the root, and trim off even with the end of it. (See Fig. 89, d.) After Fig 87 fitting the band properly, remove it and -^^^ solder a piece of pure gold plate, say about ISTo. 34, on the outer end. (See Fig. 89, e.) This can be done quickly by placing the plate in the hand and pressing the band onto it with the thumb for a fit, then sol- dering in the flame of a Bunsen burner. Punch a small hole through the plate to take the pin in the crown, and replace in position on the root after trimming off the exposed edges. ISTow take a piece of thin pure gold, say ISTo. 34 or 36, with ears as shown in Fig. 90, f, punch a hole through it, slide it over the pin of the Logan crown, and burnish tightly to the base of the crown. (See Fig. 90.) ]N"ext warm the pin and place a sufficient quantity of Parr's fluxed Fig. 89. Fig. 90. wax around it as shown by dotted lines. Fig. 90. Replace the Logan crown on the root (with the cap in position), force home until the labial edges of root and crown meet, obtain the proper alignment, and cool and harden the wax by using a napkin with ice-water. Then remove the crown and cap together, held in proper relative position by the wax. (See Fig. 91.) Trim off the surplus wax and invest. (See Fig. 92.) Remove all the wax possible between the crown and the band, and flow 20-carat gold solder into the space. The wax which will necessarily remain, PORCELAIN CROWN WITH COLD COLLAR ATTACHMENT, fjl being fluxed, will carry the solder into every crevice and give tlie crown great strength. Finish the band and the soldered edges, and the result will be a strong and perfectly aligned crown. ^ Should an unusual alignment of the porcelain crown with the root be required and the position of the pin interfere with securing it, vary the process as follows: When the piece of thin gold has Fig. 91. Fig. 92. been fitted to the base of the crown as shown in Fig. 90, cut off the pin close to the surface of the gold and cement the gold to the stump of the pin with wax. Fit the cut-off pin in the root-canal and to the cap, cement pin and cap together, remove and solder, l^ext place a proper quantity of wax on the surface of the cap, insert in the mouth and adjust the crown mth the gold on its base Fig. 98. Fig. 94. in position against the wax to the surface of the cap. Then re- move cap and crown, invest, and solder the same as previously described and illustrated in Fig. 92. Dr. E. C. Kirk, of Philadelphia, uses for bicuspids and molars a Foster crown in combination with a collar (Fig. 93). A collar lA method quite similar to that just shown, but omitting the band, was described by Dr. Gordon White in the Dental Cosmos for January, 1893. 62 ARTIFICIAL CROWN- AND BRIDGE-WORK. is made, and, on being fitted to the root, is cut narrow on the buccal side, and left wide on the palatal, so that it shall extend nearly to the cusp of the crown when finished (Fig. 94). (The seamless gold collars are well suited for this style of crown.) The crown selected should have a somewhat greater circum- ference at the base than the collar, so that when ground down somewhat conically on its lingual and approximal surfaces it can be tightly adjusted to the collar. If a crown smaller than the collar is used, a tight joint cannot be 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 oxyphosphate 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 caps the root and attaches a Logan crown in the following manner: First, the root is shaped, the outer margin beveled about the thickness of the gold used, to give a proper form for close adapta- tion of a cap. Then an impression is taken and a die made in the gold seamless cap method (see Chapter VII). To strike up the cap, place ISTo. 32 gauge gold plate on a cushion of lead, hold- ing the die firmly on the gold where you wish to produce the cap, and strike until the required depth is secured before removing 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 for the pin, leaving the raggedness made by drilling to catch in the cement. Place the cap on the root and fit the porcelain crown accurately to it in the desired occlusion and position. A Logan crown can, with little grinding, be made to do good service (Fig. 95). A crown having the H -shaped pin, but square on the edge, like some of the early patterns of Logan or Bonwill crowns, would reduce the time of setting and give best results. Having polished the edges of the PORCKLjAIN CROWN WITH GOLD COLLAR ATTACHMENT, gg cap, the crown is adjusted as follows: Place oxyphosphate cement in the countersunk portion of the porcelain, and with the gold ferrule or cap in place, properly adjust the crown. When the oxyphosphate is hard, remove the crown and cap and solder the pin to the inside of the cap, with a very small amount of soft solder, — tin and lead, — using muriate of zinc as a flux, a few blasts of the blow-pipe being all that is required. Fill the root- canal and the inside of the cap with oxyphosphate and press the crown to place (Fig. 96). Fig. 95. Fig. 96. Fig. 97. Fig. 98. In most cases the gold band 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 ordinary cases, which prevents the appearance of gold (Fig, 97). Dr. Bonvdll's plan is to cap the tooth vidth a platinum or gold cap having a slot, into which the pin passes as it is slipped on the root (Fig. 98). The crown is then fastened on the post and cap with amalgam. Dr. S. S. Stowell suggests the following method of applying porcelain crowns, with or without a countersunk base in which a post can be cemented, forming what he calls the "Simplicity Crown" : The end of the root is prepared in the usual manner and slightly countersunk. The porcelain crown (an ordinary pivot. 64 ARTIFICIAL CROWN- AND BRIDGE-WORK. an English tube tooth, or a Ilowland-Perry crown) is then fitted in position, and the glazed surface of the base and cavity removed to secure better adhesion of the cement. A How screw-post, preferably of iridio-platinum, is inserted in the root in alignment with the cavity in the croAvn. After the screw-post is set, a groove is cut on the end of the root, around the post, with small- sized engine-burs. This groove is filled with copper amalgam, the Fig. 99. crown placed on the root, and the excess of amalgam pressed out. The crown is then removed, filled with oxyphosphate cement, and pressed back in place. The excess of cement exudes on all sides, and carries with it any excess of the amalgam. The crown is held in position until the cement sets. Fig. 99 shows an incisor and a bicuspid made by this plan, when ready for adjustment; also a sectional view of the completed incisor. OHAPTEK III. PORCELAIN CROWNS WITH RUBBER OR VULCANITE ATTACHMENT. Fig. 100. Fig. 100 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 bent 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 post soldered and strengthened at the point D. The backing is then grooved and notched slightly, wax applied, the crown ad- r justed to the root, and the wax shaped so as to a\ form a foundation and overlapping edge at the palatal portion (E), and also extend around the post up the canal. The crown is next removed, invested in a fiask, packed with rubber, and vulcanized. In trimming and finishing, the rubber is allowed to form a partial band or collar around the palatal portion of the root, where it will not show. It is then cemented on to the root with oxy phosphate. A Temporary Crown. — Fit in the root-canal a post of metal, preferably made of German silver wire. Let the post extend out of the canal about one-eighth of an inch and roughen the sides. Perforate a disk of the heaviest pattern tin with the post, and fit the tin to the end of the root. Fit a suitable two-pin. rubber porcelain tooth to the disk. Groove out the porcelain, if necessary, to fit over the post. Wax the porcelain tooth to the disk and post, remove and invest in plain plaster of Paris. Remove the wax with boiling water, and, in its place, melt fusible metal and instantly press down firmly into the invest- ment with a napkin over the finger; cool, remove, trim, and cement on the root with gutta-percha that softens at a low heat. 6 65 THE GOLD SYSTEM. CHAPTER IV. GOLD COLLAK CKOWNS. This style of gold crown includes those methods which consist in banding, capping, and hermetically inclosing with gold the end or the neck of a root, with or without any portion of a natural crown, for the purpose of securing stability to the artificial crown, preventing fracture of the root and decay of the parts, thus per- manently preserving them. This method possesses much practical value as a preserver of tooth-structure and restorer of usefulness to the teeth, and affords excellent supports for bridge-work. Collar crowns, the use of which has become quite general, have been described by many writers in the past. Dr. William H. Dwindle relates the application of the method to a crown with a porcelain front,^ and Drs. W. IST. Morrison^ and J. B. Beers'"' tell of it 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 different f ormff of crowns and roots, and of the anatomical structure and relationship of the contiguous parts, is most essential for the perfect construction and adaptation of collars, bands, or ferrules, as they are variously designated. ' American Journal of Dental Science, April, 1855. ^ Missouri Dental Journal, May, 1869. ' Circular to dental profession, 1873. * J. Patterson Clark, 1836. ^ Article on Writings of M. Mouton, 1746, by Dr. William H. Trueman, Inter- national Dental Journal, October, 1897. 66 THE (J()NSTRUaTI()N AND ADAPTATION OF COLLARS. 67 Fig. 101. Fig. 102. Many devices and methods in use facilitate this operation, but its skillful performance can only be attained by study and practice, as is proved by the easy and perfect manner in which it is done bv experts in crown- and bridge-work, who use no appliances but pliers and shears guided by an intuitive per- ception of the requirements of each case. The collar is preferably made of coin gold, or 22- to 23-carat gold plate. Pure gold plate lined with platinum is also used, and platinum^ plate in special cases. Gold plate of No. 28 to 'No. 30, or gold and platinum about 30, U. S. standard gauge, affords the requisite strength, to- gether with easy adaptation to the form of the crown or root. The size of the cer- vix of the root or dimension of the natural crown to be capped, and whether it is to only effect restoration of the natural crown or to additionally give support to bridge- work, should govern the choice of the gauge of plate to be used. Cuspids and molars require a heavier plate than small laterals or lower centrals, and in all forms of gold caps the gauge should be increased when they are to support bridge-work. The natural crown or root having previously been properly prepared (see page 35), a strip of the metal is cut of the length i-equired, and generally from one-fourth to one-half of an inch in width (Fig. 101). at joint is beveled with a file (A, Fig. 102) Fig. 103. The end to underlap The strip is then bent with suitable pliers (Fig. 103) to the average form (Fig. 104), any special deviation from such average being noted (Fig. 105), * The use of platinum plate, 62 to 34 gauge, is recommended to students, as collars formed of this metal are not apt to be melted in any of the soldering processes. If very thin platinum is used, pure gold can be flowed over the outer surface after it is adapted to the cervix, to stiffen it. This method is excellent when a small, narrow collar is required for an incisor crown which is difficult to adjust to the form of the root. 68 ARTIFICIAL CROWN- AND BRIDGE-WORK. and to the size of the cervical periphery of the root of the tooth to- be crowned. 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 re- moved and cut so as to al- low the ends to lap over slightly. The adaptation to the root is then con- tinued, during which pro- cess the metal should be clamped at the joint, 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 i& made at this mark by plac- ing there the least possi- ble quantity of solder, or,, better, fluxed solder fil- ings, and holding the collar with a clamp in the flame of an alcohol lamp or a blue (Bunsen) gas flame. Another method is to grasp the seam of the col- The palatal side of the superior molars, in many •. ■■ * 1 "J "fl cases, is of the large oval form indicated by the outer ^^^ ^^ ^^® CCrVlCai Side Wltll line to the form of the first molar. The small spurs g^ clamp fsce Fio". 150) 01* indicate the points generally found the most suitable . , to make the joint. With COmiUOU tweCZCrS held by pliers, or, better still, by a small hand-vise (Fig. 106), and unite the extreme outer end of the seam by an atom of solder or fluxed solder filings with a blow-pipe. The points of the clamp or tweezers prevent the jBolder from flowing along the joint. The cervical side of the THE COXSTIWC'TJON AND ADAPTATION OF COLLARS. 69 collar is thus left open, which admits of the collar being slightly contracted, if desired, and accurately burnished to the root. The solder can then be flowed across the collar and the joint closed. The collar is then slipped on the point of a small anvil, and the joint tapped and trimmed level. A method by measurement is as follows: The root is encircled with a strip of thin sheet copper, previously annealed, one-six- teenth of an inch or less in width, and the copper fitted to the ■cervix. It is removed, and cut so there will be a slight lap-over of the ends on the root, then again fitted to the root, and the posi- tion of the lap-over end marked on the copper. This little strip of copper, being soft and flexible, can be most accurately fitted to the root without inconvenience to the patient, and when removed shows the exact length and shape to cut the gold or platinum for the collar. Fig. 105. Pio. lOfi. Q^D Upon a strip of the metal to form the collar, from one-quarter to one-half inch in width, is laid the copper pattern, and the exact length required for the collar is marked on the metal, which is then cut a trifle longer than the mark indicates (less than one- sixteenth of an inch), to allow for an over-lap joint. It is then bent and the ends brought together, the outer end placed even or flush with the mark, and soldered as above described. The collar is next bent to the shape of the root, when it is ready to be ad- justed. This method is simple and practical, and also economical^ as it accurately defines the amount of plate required. To measure with a wire: Form a loop of copper wire, about 30 gauge, by twisting the ends together with pliers. Slip the loop over the tooth or root, press the wire down under the gum-margin. 70 ARTIFICIAL CROWN- AND BRIDGE-WORK. and twist the ends witk the pliers until the loop fits tightly at every point (Figs. 107 and 108). Slip ofi" the loop, cut it in the center and extend the ends lengthwise in opposite directions, as shown in Fig. 109. Then lay it on the surface of the plate of Fig. 107. Fig. 108. Fig. 109. which the collar is to be constructed, and mark the length. Cut the metal beyond this mark sufficiently to allow for an over-lap; bevel and lap the ends to the mark and solder them. When a mandrel is used in forming a collar, the size or shape is first taken with a wire. The wire ring is then carefully re- FiG. 110. Fig. 111. illllllllllllllllliilllll!lllllil!llllllllllllllllll|lilllll!ill!l|!|llilllllllllllllllW moved, laid on a piece of air-chamber tin, a piece of flat iron put over it, and with a blow from a hammer on the iron the wire is driven into the tin (Fig. 110). The wire ring is removed from the tin, slipped on a mandreP that represents the form of the root to be crowned, and pressed down gently as far as it will go without stretching the wire (A, Fig. 111). The distance from the end of the mandrel to the wire is then measured and marked on a strip of paper, and the wire removed. The gold to form the collar is then bent and shaped on the mandrel, with the edge which is to form the cervical por- ^A description of mandrels will be found in the chapter on the "Mandrel System of Bridge- Work. " THE CONSTRUCTION AND ADAPTATION OF COLLARS. 71 tion (B) placed a little below the line of the wire (A), as shown by the measurement previously taken. The ends of the gold are beveled, slightly lapped, and the edge of the lap-over marked (C) and soldered. The collar is then shaped to the form given by the wire in the tin, after which it is ready for adjustment in the mouth. The wire method of measurement will be foimd prefer- able for roots for collar crowns with porcelain fronts. Fitting of collar to root or tooth. When the collar has been formed, it is adjusted on the root and pressed or, by the aid of a piece of wood, one end of which is placed across the outer edges of the collar, tapped, up to the margin of the gum. A line parallel with the margin is marked with a sharp-pointed instrument on the Fig. 112. Fig. 113. Fio. 114. collar (A, Figs. 112 and 113), which is then re- moved, trimmed to this mark, readjusted, and again marked (B), and the process continued until the collar fits pro- portionately under the margin of the gum. If, on adjusting, a collar is found a trifle too small, it is easily enlarged by tapping the gold with a riveting hammer on an anvil (Fig. 114), the edge-end of the collar marked B, Fig. 102. By this means the surplus gold at this point can be thrown into the collar and its circumference proportionately enlarged without altering its gauge. If, on the contrary, the collar should prove to be too large in circumference, the difliculty can be remedied by slitting the gold nearly but not entirely across the side oppo- 72 ARTIFICIAL CROWN- AND BRIDGE-WORK. site the joint, beveling arid lapping tlie edges slightly, soldering, and trimming. The edge is then burnished to the periphery of the root. For the purpose of fitting collars a set of burnishers should be used especially formed to suit the different positions and avoid irritation of the margin of the gum. (See Fig. 115.) Fine serrated foot-shaped gold-foil condensers can be advan- tageously used to flatten a stiff or angular point of a collar. The application of a local anesthetic, such as cocain, will lessen the pain attending the operation. Cocain is very effective in tlie form of a saturated solution in glycerin. The parts should be surrounded with a napkin, or with bibulous paper, and dried. Fig. 115. Then a drop of the solution is placed on a slab, and' a little at a time is carried on the edge of a thin burnisher and applied well up under and around the free margin of the gum of the tooth operated on. When this has been done, some of the excess of the solution, which will usually be found at the cervix, may be rubbed on the labial and palatal sides of the gum. The patient should be directed not to swallow the saliva during and for some time after the application of the cocain. The anesthetic effect pro- duced by this method will usually be found sufficient to partly or entirely divest the operation of pain, and of such duration as to seldom require repetition except at subsequent stages of the operation. Electrolysis will effect rapid diffusion of the cocain (cataphoresis), the solution of cocain being placed on cotton against the sides and margins of the gums. A weak current of electricity should be used, the positive pole being applied to the cotton and the negative pole to the cheek or held in the hand of the patient. COLLAH CROWNS Ifyai/'JNKJAL/A- CONSI DI'JiKD. 73 COLLAR CROWNS HYGIENICALLY CONSIDERED. The principal argument 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 be theoretically and practically true of a rough or porous substance encircling the root, or of an imper- fectly and unskillfully adjusted or cemented ferrule or collar which would by its presence hold a position analogous to a cal- careous deposit, but no such comparison can be fairly made with a perfectly fitted collar, forming at its edge a smooth and im- perceptible union with the sides of the root, and presenting a uniform and benign surface to the investing membrane. In case of perfectly adapted collars, when any irritation of the mem- brane exists, it will be. found to result from such causes as usu- ally produce it when the natural cro^vns are present, namely, dental concretions. A tarnished and unclean condition of the surface of the gold of the collar will produce irritation of the membranes, which is a matter independent 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 platinum or iridium, or one of gold and platinum crown-metal, presenting the platinum surface, is suggested in preference to gold, as these metals will not be affected, but will constantly present an untarnished surface. "When evidences of a tendency to pyorrhea alveolaris exist, a collar adjusted to support bridge-work should be extended well under the gum-margin, or the edge of the collar kept consider- ably above it. Where pyorrhea alveolaris is present, a collar of fine gold, properly fitted and extended well up over the exposed section of the surface of the root, has often a tendency to retard the disease, as calcareous deposits do not adhere to the smooth surface of the gold so readily as to the dentin. CHAPTER V. GOLD COLLAR CROWNS WITH PORCELAIN FRONTS. INCISORS AND CUSPIDS. ' This stjle of crown for incisors and cuspids, as originally made by Dr. C M. Kiclimond, 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 and the center of the cap 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 was formerly 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 cemen- tation. These improvements enhance its value as a crown, and materially change the process of its construction. In making an incisor or cuspid crown of this style, the collar, having been 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 side of the wheel should revolve toward the root, its motion even being reversed for that purpose when necessary, the idea being to turn the feather-edge of the metal of the collar over the end of 'the root. The work will then present the ap- pearance shown in Fig. 116. The cap is made by placing the outer edge of the collar against the surface of a piece of very thin platinum plate or heavy foil, adapting the platinum to the edge of the collar and then uniting the platinum to the collar with solder in a Bunsen flame (Fig. 117). The quantity of solder used must be very small, barely sufEcient to unite the parts, and it should be placed on the plati- 74 GOLD COLLAR CROWNS WITH PORCPJLAJN FRONTS. 75 num outside of the collar. Used in that manner it will not flow over the inside of the collar and interfere with the fit of the cap. The process is facilitated by first merely attaching the platinum, with the solder, to the edge of the collar, then readapting, and finishing the soldering. The platinum is next trimmed to the collar, and the cap adjusted on the root. The labial section of the surface of the cap is then burnished to the end of the root (A, Fig. 116). The root-canal having been slightly enlarged, a pin of round iridio-platinum wire, ]S[o. 16 or 17, U. S. standard gauge, — filed a little smaller for laterals or other roots which require it, — is slightly tapered at the point, fitted to an aperture made in the cap, and to the canal (B). The pin is then cut off even with the cap, removed, and temporarily laid aside. Fig. 116. Fig. 117. Fig. 118. Fig. 119. A hollow wire, the open space in the center of which is very small, affords the advantage that it can be drilled out of the canal in a comparatively easy manner if for any reason it be- comes necessary to remove the crown, as the drill will follow the fine opening in the center of the wire. To accurately fit a post in a root-canal which for some reason has been reamed considerably, use a piece of platinum wire of a gauge which will fit the end of the canal. Twist a narrow strip of platinum foil on the post from the point downward, and fit post and platinum to the canal. Remove post and platinum foil together and solder them with a pellet or two of gold foil by hold- ing in a Bunsen flame. A plain-plate cross-pin tooth, suitable in form and color, is ground and fitted in position on the cap. The labio-cervical edge of the porcelain (A, Fig. 118) should be flush with the edge of 76 ARTIFICIAL CROWN- AND BRIDGE-WORK. the collar, and meet the margin of the gum. It should be cut out at the base (B) so as to form a slight space just over the end of the pin. The tooth is then backed with very thin pure gold, gold lined with platinum, or pure platinum foil. Platinum gives a faint blue shade, and gold, or gold lined with platinum, if the gold side is toward the porcelain, a slight yellow shade. The backing should extend as far as possible under and between the tooth and the cap, as the solder will flow in and fill the space, thus giving strength and continuity of structure. This result can also be effected by first simply backing the porcelain with gold or platinum and then shaping a piece of very thin platinum foil to the base, extending from A to B, heating the porcelain, veneer- ing with a mere film of resin and wax, and by pressure with a Fig. 120. , Fm. 121. Fig. 122. napkin or cotton causing the foil to adhere to the surface of the porcelain. The backing, if bent over the incisive edge (C) at an obtuse angle to the line of the back of the tooth, will protect the porcelain in occlusion. A narrow strip of fine gold placed trans- versely across at that point previous to investing, and united in the soldering of the backing, will answer the same purpose. If the platinum backing used is of the nature of foil, it is advisable to rivet over it on the back of the tooth a piece of gold plate smaller in size, and in which a number of perforations have been made with a punch forceps. This will insure against melting the plati- num foil off the porcelain with the gold solder, which may occur if a pointed flame is used. The solder will flow through the per- forations and unite the gold with the platinum under it. The tooth, when backed, is secured in position on the •eap-'With a compound of wax and resin, and the whole adjusted in the QOLD COLLAR CROWNS WITH ROIiCKLAIN FRONTS. -J J 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 deter- mine the exact line for the pin, and the case is ready for invest- ment. After the fitting of the pin to the root and root-canal, as was described when the cap was formed, some prefer to solder it to the cap, for which purpose it should be adjusted in position and cemented with wax, then removed, invested, and soldered (Fig. 119). At this stage of the work, if desired, an impression can be taken in a small impression cup (Fig, 120) with either plaster or modelling composition. The cap should be removed in posi- tion in the impression. 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 sulfate of potassium to quicken the setting, makes what is con- sidered to be the most suitable investing material for crown-work. The metallic section of the crown, when invested, should be left exposed at the sides, about as illustrated in Fig. 121, but the porcelain should be carefully covered. Pour boiling water on the investment when desirous of removing the wax before heating, but never attempt to remove it with an instrument. Many sim- ply allow the wax to burn out. This is always done when fluxed wax is used. The investment should be first heated over a Bunsen burner, and then removed to a charcoal soldering-block. Gold solder cut in small pieces is then placed in and over the aperture between the porcelain front and the cap. By uniformly heating the entire investment, especially underneath and in the direction A, with a large flame from a gas blow-pipe, the solder is melted and flowed between the porcelain and cap. More solder should be added, and melted in this manner until the space between cap and porcelain is filled in and continuity of structure assured; but if an excess is used, it is apt to bulge or flow out over the collar. After letting the body of the investment slightly cool, additional solder is then placed on the backing and cap, and with a small pointed flame melted and flowed over these parts. Only 78 ARTIFICIAL GROWN- AND BRIDGE-WORK. sufficient gold should be used to insure restoration of contour. When soldered, after having been placed in acid and thoroughly divested of borax, the crown is ready for the finishing and polish- mg process. Fig. 122 represents the completed crown. When it is desirable to protect the incisive edge of the porce- lain against fracture in use and at the same time have the gold invisible, the porcelain should be ground in the manner illustrated Fig. 123. A\ ^^ \^ at A, Fig. 123, The gold in the final finishing should be brought on a straight line to the edge of the porcelain as shown at B. This will protect the edge of the porcelain in use, and render the gold invisible when viewed from the front. BICUSPIDS AND MOLARS. Bicuspids crowned by this method will have greater strength if a portion of the palatal section of the natural crown is reserved (Fig. 23), and the band or collar made deep enough to cover it. The end of the root is capped after the manner of the typical central already described, one or two pins being used in the canals as required. A porcelain cuspid tooth, or a bicuspid front, is then ground, backed, and adjusted on the cap to represent 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 porcelain is ground GOLD COLLAR (JROWNS WITH PORCELAIN FRONTS. 79 clear of the antagonizing teeth (A, Fig. 124), AVith a die of suitable size representing the occluding surface of a bicuspid, as illustrated in Fig. 125, a piece of pure gold plate (about JSTo. 30 gauge) is swaged (Fig. 126) and the cusps filled in with 18-carat solder or gold plate. ^ The cap is then trimmed (Fig. 127), ground, and fitted to the occluding edge of the porcelain front (Fig. 128) in proper position as regards occlusion, and the wax attaching it is shaped to the contour of the crown (A). A piece of very thin gold plate or of No. 60 foil (B) is then adjusted on each side of the crown, which is invested (Fig. 129). The long ends of the two side-pieces of gold plate are designed to retain theni in position, as the investing material should be removed from Fig. 124. Fig. 125. Fig. 126. Fig. 128. Fig 129. the portion inclosing the sides of the crown (A). Mica — isin- glass — is recommended for this purpose, and is preferable to metal. In the process of soldering, the solder is placed in the aperture at B, and the flame of the blow-pipe being directed on the exposed sides of the gold at A, the solder is flowed into every part, form- ing perfect continuity of structure of the metallic portion of the crown. If this aperture at A is left open without the gold or mica, and the solder is first flowed in the interstices as described in soldering an incisor crown, the remaining solder necessary to con- tour the part can be added, if the pointed flame is used and not applied to the other portions of the crown and investment. In finishing, the surplus gold is trimmed to the contour of a bicuspid tooth. Fig. 130 represents the finished crown. 1 A hard-flowing solder is be.st for use in filling cusps to protect porcelain fronts to crown- or bridge-work. It is made of two parts 18-carat gold plate and one part 18-carat solder. The plate and solder should be melted together and rolled out quite thin and kept ready for use. 80 ARTIFICIAL CROWN- AND BRIDGE-WORK. The method described 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 gold plate, which have been previously melted into the form of small balls and flattened out on an anvil. These, laid in position and united with solder, are shaped in finishing to represent the palatal cusp (Fig. 131). The porcelain front should be backed so that the solder can be flowed over its occluding edge. Fig. ISO. Fig. 131. Fig. 132. Fig. 133. Another method is to extend the palatal part of the collar down as shown in Fig. 132, and then fill in the space with solder. In finishing, the gold is trimmed to the form of the crown. As much as possible of the natural crown should be left at the palatal side of the collar. The exposed edge of the collar may be slit and brought in against the side and soldered to give contour., With this form of collar one pin, in the palatal root-canal, is sufficient. It should be allowed to extend out of the cap enough to just touch the lower teeth when they are occluded. The exposed end of the pin will be an exact guide in the soldering as to the amount of solder required to form the grinding-surface. In this and in the method just previously described, the porcelain front can be soldered and the palatal cusp formed in the one investment. The method of construction of molar crowns with porcelain fronts is similar to that for bicuspids (Fig. 133). Dr. 8towelVs Method. — 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 crown or an ordinary counter- sunk tooth, but in most cases the Logan crown, having a strong ^Dental Cosmos, vol. xxix, page 641. GOLD COLLAR CROWNS WITH POIiCELAJN FRONTS. 81 pin, is preferable. The pin is first cut off, then the tooth is ground to fit on the cap, the porcelain and the stump of the pin being reduced alike evenly and smoothly; after which the stump of the pin is ground with a small wheel below the surface of the porcelain (Fig. 134). The tooth is then invested (Fig. 135) and pure gold fused on to the platinum jDin, and while in a fluid state it is with a wax spatula 'spatted' down flat (Fig. 136). Fig. 134. Fig. 135. Fig. 136. Fig. 137. Fig. 138. The gold is then filed or ground down even with the porcelain, and at the palatal border the tooth is ground to bevel back until the gold is reached (Fig. 137). The tooth is then secured in place on the cap with wax cement (Fig. 138), 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. 139) caused by the grinding of the bevel on the crown. The Fig. 139. Fig. 140. Fig. 141. Fig. 142. Fig. 143. 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 finally attaches itself to the pure gold already at- tached to the stump of the platinum pin. Fig. 140 represents the completed crown. A sectional view of a like crown (Fig. 141) also shows the organization in detail. A porcelain crown can be used to represent any of the teeth in the same manner. (See Figs. 142 and 143.)" 7 82 ARTIFICIAL CROWN- AND BRIDGE-WORK. GOLD CROWNS WITH PORCELAIN FRONTS FOR 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 opera- tion to perform, the pulp is frequently found unexposed and in a normal condition. The importance of its preservation in such a case is unquestionable. Fig. 144. Crowning in Cases of Abrasion. — In a case of ex- tensive abrasion of the incisive edges of the anterior 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 with a porcelain front with- out the pin. Fig. 144 gives an outline of the con- struction of such a crown. If a case should suggest the necessity of a pin, a short one can be so inserted between the line of the pulp-chamber and the palatal wall. CHAPTER VI. ALL-GOLD COLL All CKOWNS FOK BICUSPIDS AND MOLARS CONSTRUCTED IN SECTIONS. The root and crown having been properly prepared, the collar is formed and adjusted as described at page 71, and the edge toward the antagonizing teeth trimmed, to fully clear them in occlusion. The collar is then slightly expanded toward the oc- cluding surface for better contour. A close knuckling can be insured by seizing the collar and the approximal tooth in the man- ner shown in Fig. 145. The collar is removed, filled with plaster, and adjusted in position. Fig. 146 represents a typical case. Fig. 145. Fig. 146. The antagonizing teeth, having been 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 to form the grinding-surf ace of the crown. The plaster is then trimmed and shaped to represent the cusps and fissures of the natural tooth, enough of the surface being removed to allow for the thickness of the plate that forms the cap. A small tube of copper, a trifle larger in circumference than the crown under construction, is filled with Melotte's "moldine," and the surface rubbed with soapstone. An impression of the 83 84 ARTIFICIAL CROWN- AND BRIDGE-WORK. lower portion of the form of the crown A to the line B, Fig. 147, is then made in the moldine, and a strip of paper wound around Fig. 147. Fig. 148. the tube, extending about an inch above the edge. Fusible alloy is then melted and poured into the mold, thus forming a die. An in- dentation is made with a punch in a block of lead, into which the die, when cold, is hammered slightly beyond the impression of the edge of the collar. By this method a die and a counter-die (Fig. 148) can, with practice, be completed in five minutes. With 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 of the plaster in the collar may have to be re- moved, if, on trial in the mouth, the cap is found a little flush. The crown, with the plaster still inside the collar, is fixed in a soldering-clamp constructed in one of the forms shown in Figs. 149, 150, and 151, which holds the parts together and permits the A, Fusible die. B, Counter-die. C, Plate to form the cap. Fig. 149. Fig. 150. The frame of this clamp is formed of iron wire, and the support for the crown of plaster, asbestos, and marble-dust. flame to reach all points. "With the clamp Fig. 149, the blow-pipe flame is the best. The other forms suggest the Bunsen flame. The parts of the crown can also be held together for soldering with iron wire in the form of a loop passed over the grinding-surface, against the sides of the collar, with the ends twisted together over ALL-GOLD COLLAR CROWNS CONSTRUCTED L\ SECTIONS, go the aperture of the neck of the crown. ISTo more solder should be used than the contour requires, as an excess necessitates addi- tional labor in finishing. y^q 151 Another method, if the crown is not to be contoured with the aid of the sol- der, is, when the cap is struck up, to melt solder into the cusps, and then adjust the cap in jDosition on the collar, for which purpose some of the plaster underneath the cap must be removed. A jet of flame from the blow-pipe is then thrown upon it in such a way as- to cause the solder to flow down on the edge of the collar and fill the seam from the inside. The objection to this method is that, when a large portion of the natural crown is inclosed by the gold, the solder will occasionally alter the inside form of the fitted cap, thereby interfering with its adjustment, which is a defect troublesome to correct. Still another method specially suita- ble in cases where all or nearly all of the grinding-surface of the natural crown is present or where the bite is close, is to adjust the collar in the mouth, and, with a small piece of wax or im- pression-compound pressed upon it, to take an impression and ''bite," in which the collar will be imbedded and re- moved. With this a model and articu- lation are made and the form of the cap shaped in wax. An impression of the cap is then made, either in moldine in a soft state in a tube, or in plaster, and a die cast. The cap is stamped on this die, then adapted to the collar by the model, and the crown finished. This method, which was first made known by Dr. IST. W. Kingsley, can be adopted when it is 86 ARTIFICIAL CROWN- AND BRIDGE-WORK. preferable to construct the crown between the visits of the pa- tient after having first made and fitted the collar. In utilizing a tooth as an abutment in bridge-work when all or nearly all of the occluding surface of the natural crown is present, a practical method of construction is to mark the out- line of the natural crown on the inner surface of the collar; then remove the collar and trim so as to leave a border of about one-sixteenth of an inch outside the mark. This border is then thinned with a corundum-wheel, and slit as seen in Fig. 152. Fig. 152. Fig. 153. Fig. 154. The collar is next adjusted on the natural crown, and the slit bor- der bent over to the form of the occluding surface, to which it is burnished. A piece of pure gold plate, about ISTo. 34 gauge, is then placed on the occluding surface of the tooth and adapted to it and to the collar. The gold may be first struck in the form of a cap by laying it on a block of lead and hammering into it a die of the surface of the tooth to be crowned (Fig. 153), or one corresponding closely to it. The antagonizing teeth are then oc- cluded on the gold, which is thereby pressed to form to articulate with the occluding surfaces. Enough of the occluding surface of the tooth crowned should always be removed to allow for the thickness of the gold covering its surface. The collar and cap are next removed and soldered. This is done by resting the collar on the cap, which is held by a pair of tweezers, or by clamping ALL-GOLD COLLAR CROWNS CONSTRUCTED IN SECTIONS. 87 the cap and collar together and placing the solder in small pieces around the collar outside the cap, at A, Fig. 154, and soldering by holding in a blue gas flame. Only sufficient solder should be used to join and fill the seams, so that it will not interfere with adjustment on the natural crown. A closer and neater joint will be obtained by at first attaching only one corner of the crown to the collar, with the smallest possible quantity of solder, Fio. 155. UPPER LOWER then readjusting collar and cap on the tooth, adapting their edges together with a foot-shaped foil condenser, and then completing the soldering. The methods described insure a perfect occlusion of the crown with the antagonizing teeth. In the absence of antagonizing teeth, or when the general form of the grinding-surface permits it, the cap can be struck up with a die similar to the one shown in Fig. 153 that approximates in size and form what is required. The cusps are then filled in, and the edges of the inner surface of the cap ground level on the side of a corundum-wheel. The en- tire circumference of the edge of the collar is also leveled, and 88 ARTIFICIAL CROWN- AND BRIDGE-WORK. the cap adjusted, clamped, and soldered. If the cusps of the cap are 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 either on the inside or outside. Fig. 156. Fig. 157. When the mere form of the grinding-surface for the crown is all that is required, an impromptu one may be made by in- denting a piece of pure or soft gold plate mth the round end of an instrument-handle on a piece of lead to form the cusps, then reversing the cap, resting it on a flat surface, and creasing be- tween the cusps with a bur- nisher. Metallic caps, or forms of the occluding surfaces of teeth for use in constructing crowns, are quickly made with the die-plate shown in Tig. 15 5,^ "in which are four groups of intaglio dies representing the peculiar cusps of the bicuspids and molars. The hubs A, B (Fig. 156) are of the sizes shown, and are made of an alloy composed of tin one part, lead four parts, melted together. The mold should be warmed! ^ Dental Cosmos, vol. xxix, page 482, ALL-(,'()LI) COf.L.lU CROWNS CONSTRUCTED IN SECTIONS. 89 the metal alloy poured in every hole, and the overflow wiped off just before the metal stiffens; this will make the butts of the hubs smooth and flat. After a minute or two the mold may be reversed, the hubs shaken out, and the casting process continued until a considerable number of hubs sliall have been made. In Fig. 157 a molar hub is shown in place on a piece of ISTo. 32 gold plate, which lies over the upper right first molar die. A succession of blows on the hub witli a four-pound smooth-faced hammer will drive the plate into the die, and at the same time spread the hub metal from the die center to its circumference, in such a manner Fig. 158. that the plate will be perfectly struck up with the least possible risk of being cracked. The flattened hub is seen in Fig. 158, which also shows at D the obverse of the struck-np hub, and at E the cameo of the struck-up plate, having every cusp and depres- sion sharply defined. The counter-die plate (Fig. 155) is made of a very hard cast metal, which will admit of the striking np of many crown plates by the means described, if the crown plates be not too thick and stiff. Of course they should be annealed be- fore they are placed over the die. If a cusp or fissure should chance to crack in hubbing, a small piece of plate may be struck up over the fissure, and then soldered to the original cap." The methods which have been described for the construction of all-gold bicuspid and molar crowns are those generally adopted in practice. Of others. Dr. J. J. R. Patrick's method^ consists 1 Dr. Patrick's crown-work methods and the principles upon which they are hased are set forth in a paper published in the Dental Cosmos for October, 1888, page 706. 90 ARTIFICIAL CROWN- AND BRIDGE-WORK. of first forming a very narrow collar and telescoping it witli a seamless cap of the form of the crown, and soldering along the line of the cap to the collar. A method of making a gold crown by stamping it out of one piece of gold plate is, make or select a metallic die for the crown to be formed; then place a piece of pure gold plate, about JSTo. 31 gauge, on the flat surface of a block of lead, and gradually stamp the die downward into the gold to about half the depth of the in- tended crown. The gold is then removed, and each side of the un- swaged portion slit and adapted to the form of the die, the full length of the crown, which is then adjusted in the mouth, the edges of the gold trimmed to the proper form, and the slits sol- dered. Dr. M. Rynear's crown is of the same general character and construction as the one just described, except that a seamless cap is used to form the crown, instead of a flat piece of plate. All-Gold Crowns for the Incisors and Cuspids. — When the teeth are abraded or short and the incisive edges flat, and the all- gold crown required is to correspond in form or be only a little longer, the gold collar, after being fitted to the tooth, is slit on the palatal or lingual side, and bent and burnished to it. The collar is then removed and the seams soldered together. This is best done by holding the collar in a Bunsen gas Fig. 159. fl^me, with the solder placed in position in very small a pieces, and only sufficient in quantity to join the seams. The collar is next adjusted to the tooth, and the gold at the incisive edge trimmed even. A flat, thick piece of gold plate or clasp-material is soldered across the incisive edge to form and inclose that portion of the crown. When the crown required is of the normal form, the collar when properly fitted should be removed at the palatal section, as shown in Fig. 159. The edge of the gold is then chamfered, and bent and burnished over the incisive edge and sides, close tO' the natural tooth. To this open section is next adapted a flat piece of gold plate, the collar is removed, and the parts are sol- dered together, using very little solder. Fluxed solder filings can be melted in the interior of the incisive edge to increase its thick- ness. 160. ALL-GOLD COL LA It CROWNS CONSTRUCTED IN SECTIONS. 91 Another method is to select a porcelain tooth of the desired form and of the size of the gold crown, and use it as a model to cast an intaglio die. The die is made by placing moldine in a pill box, smoothing off the surface, and imbedding half of the por- celain tooth with the palatal or pin side down. Kext wind some paper around the box, slightly warm the porcelain tooth, and pour in fusible metal. On this intaglio die shape a piece of gold plate, 30 to 32 gauge, to the form of the labial sur- face of the crown. Kemove and bend the metal round to the form of the sides and palatal section of the tooth, trim the meeting edges, and solder. (Fig. 160.)^ A fusible metal die of the prepared form of the natural tooth is a material aid in the construction of this style of crown. In pulpless teeth with only a little or none of the natural crown remaining, the root can be shaped and capped as for a collar crown with a porcelain front (see Chapter V), using a gold front instead of the porcelain. This can be made by shaping or stamp- ing the form of the labial face of the tooth required in gold plate, mounting it in position on the cap as in the case of a porcelain front, and attaching with solder. The concave portion at the palatal side of the gold front is filled in and shaped at the same time. Fig. 161. To correct the accidental presence of solder on the inside of a crown, which interferes with its adjustment, make a thin paste of 1 Dr. J. T. Usher, Dental Cosmos, vol. xl. 92 ARTIFICIAL CROWN- AND BRIDGE-WORK. rouge and oil. To determine exactly at wliat point the gold strikes, paint the natural tooth with the paste and place the crown upon it. The interfering spot will be exactly marked on the gold. This should be trimmed, and the crown again inserted to determine whether enough has been removed. If preferred the paste can be placed on the inside of the gold crown, when the in- terfering point will be marked on the natural tooth, which can then be trimmed instead of the gold to permit proper adjustment. Pig. 162. Fig. 161 represents a case of abrasion of the lower teeth, to Avhich all-gold crowns have been applied, as shown in Fig. 162. In such cases, owing to the attrition of the occluding teeth, the cap forming the occluding surface should be constructed of heavy gold and platinum plate. An artificial plate replaces the upper teeth. CHAPTEK VII. THE GOLD SEAMLESS CAP-CROWN. This method consists in the use of a gold seamless cap for the construction of the required root cap or crown. INCISORS, CUSPIDS, AND BICUSPIDS, WITH PORCELAIN FRONTS. Incisor, cuspid, and bicuspid crowns with porcelain fronts are constructed by this method as follows: The natural crown is ground down to within about one-eighth of an inch of the gum at the palatal wall, or enough to clear the antagonizing teeth when occluded, and slanting from the posterior edge of the pulp-cham- ber to the cervico-labial 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. 163). A die of the end of the root is then made. For this purpose an impression of the part is taken with gutta-percha on the end of a piece of wood trimmed to the proper size, or, better still, by placing some plaster of Paris with a little sulfate of potas- sium, mixed to the consistence of a paste, in a tube formed of a strip of copper about one and one-half inches in length and three- eighths of an inch in diameter, cut out on the sides to the depth of half an inch, with the flange for the palatal side shortened^ (^ig- 164). The impression thus taken will be con- fined almost entirely to the end of the root to be capped. When gutta-percha is used, it is cooled and dried per- fectly. A strip of paper is tied around the wood or tube, and a die cast with the fusible metal. The cooling is hastened by im- FiG. 163. Fig. 164. ^ See article on " Molds and Dies, .soldering. which describes how to make a tube without 93 94 ARTIFICIAL CROWN- AND BRIDGE-WORK. mersion in a glass of water. When cool, the die is removed from the mold, and the metal is trimmed, with file and chisel, a little deeper than the gum has permitted the impression of the root to be taken, and without altering the form of the end of the root (Fig. 165). A counter-die is then made bj punching a hole in the surface of a block of pure lead, and with a few blows of a hammer driving the die into it. A cap of pure gold, or preferably of platinum, can be formed by x^lacing a piece of the plate, J^o. 30 gauge, of suitable size upon Fig. 165. Fig. 166. Fig. 168. Fig. 167. 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. 165). The gold should be withdrawn from under the punch and annealed several times during the process. Caps can also be made with a stamping-press. (See page 101.) The cap is then annealed and swaged on the die to the form of the end of the root (B, Fig. 165). The palatal portion of the cap should be allowed to go well up under the free edge of the gum, and at the cervico-labial edge it can be, if preferred, cut out to the edge of the root. In the process of adjustment, the edges which fit under the gum should be marked and trimmed as directed in describing the construction of a collar crown, and THE GOLD SEAMLESS (JAP-CROWN. 95 then burnished close to the sides of the root and into the orifice of the root-canal, forming a perfect-fitting seamless cap (Fig. 166). An iridio-platinum pin is then fitted in the root-canal and soldered to the cap (Fig. 167), or afterward adjusted as in the construction of the gold collar crown with porcelain front (page 75), with which operation the remainder of the process of con- struction is identical. Fig. 168 represents the completed crown. The advantages of this style of crown are, simplicity, as the formation of a collar is avoided, and strength, as a large portion of the natural crown can be left at the palatal side. This affords a stronger and more reliable foundation than can be obtained at any other point, as the direction of the force in mastication is forward at an angle with the line of the root, and although the gold of the cap, where it encircles the root at the cervico-labial edge, is entirely removed, the crown is still held securely. In a paper on the subject of preserving and utilizing this part of the tooth, Dr. W, F. Litch, of Philadelphia, describes a crowning operation,^ in which he constructed the cap of platinum by slitting a piece of the plate in a number of places, adapting it to the end of the root, and then soldering the whole together. This operation is not, however, so easily or so satisfactorily performed as the method above described. In some respects pure platinum is preferable to gold in capping roots, as it is less likely to be affected by the secretions of the mouth. ALL-GOLD SEAMLESS BICUSPIDS AND MOLARS. All-gold seamless crowns for bicuspids and molars that will accurately fit the natural crown and root, and occlude properly with the antagonizing teeth, are easily and quickly formed, if sufiicient of the natural crown remains to admit of temporary restoration of its contour with gutta-percha or any other suitable plastic material. The sides of the natural tooth should be re- moved at least the thickness of the plate to be used. An im- pression of the restored tooth is then taken in plaster or gutta- percha in a tube, as explained on page 93, and a die then formed of fusible alloy; or a plaster model can be made from an impres- sion of the tooth taken in wax, and a mold obtained from the model with moldine. Additional preparation and shaping of the ^Dental Cosmos, vol. xxv, No. 9, page 449. 96 ARTIFICIAL CROWN- AND BRIDGE-WORK. natural crown to receive 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 por- tion of the natural crown or root remaining should be shaped and prepared to receive an artificial crown. Then the form of the cervix is ascertained with a wire as described on page 69, an impression of the parts taken in wax or impression compound, and the wire 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 represents the exact form of the root (Fig. 169). Tig. 169. Fig. 170. Another method is to fit a copper collar accurately to the root, removing it in the impression. In such a case plaster ought to be used. When the model is made the collar, on being cut and re- moved, will present the exact form of the neck. From a "bite" taken in wax a plaster articulation is then made to the model. A hole is 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 form of the grinding-surface for the crown. The sides of the plaster are then trimmed to the form of the crown, and the whole carved in detail (Fig. 170). As the crown will always stamp larger in circumference than the die, in proportion to the thick- ness of the gold used, an allowance must be made by trimming THK GOfJJ SK.IM/J:ss CI /'-Ch'DU.W 97 off a proportionate amount of the grinding-surface. When the plaster model for the crown is made, it is separated from the rest of the model at the dotted line seen in Fig. 170, and trimmed in the form shown hy the cast A, Fig. 171. From this model the die is made in a tuLe with nioldine and fusible metal as described at page 84. Tlie cast should always be lengthened at the neck, so that the crown when constructed shall have a sui-plus in depth of gold to allow for any trimming or shaping of the collar that may be required. The counter-die (B, Fig. 171) is made by punching a hole in a block of lead and hammering the die into it. The crown, which is usually formed of pure gold, or gold slightly al- loyed, or gold lined with very thin platinum from Xo. 30 to iSTo. 32 gauge, is then made by first stamping a piece of plate (see page Fig. 171. Fig. 173. Fig. 174. 00 J ill the form of a cap of gold (A, Fig. 172). The cap is then placed on the cast, and mth the aid of the counter-die (B, Fig. 171) swaged to the form of the crown B, Fig, 172. A piece of kid-leather or rubber dam should be used to cover and protect the gold from the lead, and to facilitate its removal from the counter-die. An allowance for the thickness of the leather must be first made, by driving it. without the gold on the cast, into the counter-die to enlarge it. If this is not done, the gold is liable to be torn in the swaging. Dr. C. B. Parker's method of stamping the piece of gold plate is to form two dies of the required crown, — the first with a cone- shaped neck up to the grinding-surface (Fig. 1T3), and the second straight on the sides (Fig. 174). The gold is stamped up on the first die, giving the grinding-surface, liut leaving tlie sides flaring, and then on the second to straighten the sides. 98 ARTIFICIAL CROWN- AND BRIDGE-WORK. Cuspid cro^vns from whicli a portion of the gold on the labial aspect is to be removed, or which are to be used entire as a sup- port for bridge-work, can usually be advantageously formed with Fra. 175. a seamless cap (Fig. 175). The necks of these crowns can be con- tracted in fitting in a contracting plate, or slit, lapped, and sol- dered, should the case so require. (For details of process of ad- justment and insertion, see "Adjustment of Seamless Contour Crowns," page 102.) ^ CHAPTEEVIII. GOLD .SEAMLESS CONT SEAMLESS roA'/'O/'A' (JliOWWS. 103 to the form of the root in the operation — until the edge meets the margin of the gum (A, Tig. 188). 2. Mark a line (B) on the gold parallel with the margin of the gum. Fi(i. 186. Fk;. 187. A 0- \ ) cm^ Via. If 3. Remove and trim to this line (A, Fig. 191). If necessary, repeat the marking and trimming until the edge meets the gum evenly. 4. Bevel the edge of the gold, readjust the crown and press it up until the edge of the collar passes under the margin of the gum, and, if the occlusion is correct, burnish the gold to the cervix. Pig. 190. Fig. 191. To Expand the Collar and Croiun. — If the collar of the crown needs enlargement, it is easily and most properly accomplished with crown expanders (shown in miniature form in Fig. 192), the points of which should be introduced at first just within the 104 ARTIFICIAL CROWN- AND BRIDGE-WORK. edge of the neck, and the gold spread sufficiently to allow it to fit over the end of the natural crown or root, the process of ex- pansion being gradually continued as the crown is brought into position. By proceeding in this manner too great expansion is avoided. To Alter a Side. — The contour of one or hoth sides can he de- pressed and the crown thus narrowed by introducing the points of a crown expander or some tool that will fit loosely inside the crown, Pig. 192. Fig. 193. then steadying the crown with the fingers, as shown in Fig. 194, and tapping the sides to be reduced with the flat end of a riveting hammer. Pliers will also accomplish it, one beak being placed inside of the crown, and the other being placed against the bulge on the outside (Fig. 193). This is necessary when the contour or the side of a crown presses on an adjoining tooth, and the crown is thus prevented from coming in proper position. To Alter the 'Shape of a Portion of the Collar or Side of a Croivn. — Slip the crown over the point of an anvil, or the end of a pair of expanders, or a small round-handled instrument held in a vise, and then tap the part to be altered with the flat end of a riveting hammer to the form desired. To Alter the Occluding Surface. — Before the crown is pressed up to its apparently proper position, the occlusion should be UOIJ) SEAMLESS COXTOtlh' ('HOWSS. 105 examined, and calculations carefully made to ol)viate any defects of articulation, which can be readily corrected at this stage by proper manipulation of the crown. Fk;. 194. Fn;. 195. To Alter the Grin ding- Surface. — Place crown in position on the tooth and flatten the part with a large gold foil condenser tapped with the mallet, or hold the crown and tap the part as shown in Fig. 195. The closing of the antagonizing teeth upon the crown by the patient with force will aid or complete the operation of articulating. To Contract the Neck. — Slightly bend in the edge of the gold at the neck with narrow-beaked pliers, and holding the crown evenly and firmly between the fingers, as shown in Fig. 196, burnish the sides and neck section inward Fig. 196. around the entire circumference of the crown. To Consiclerahly Contract a Croivn. — Slit the gold longitudinally at the palatal or lingual side its full length to the grind- ing-surface as shown in Fig. 197, bevel off the edge to lap under, con- fic4. i97. tract the crown, readjust to the tooth, remove, place the smallest quantity of dampened flux solder filings in the seam on the inside of the crown only, and solder by holding in an alcohol flame. Then proceed with the further ad- justment of the crown. 106 ARTIFICIAL CROWN- AND BRIDGE-WORK. The outside line of the seam can be stoned off and polished after the crown has been fitted, and additionally soldered to strengthen the sides or grinding-surface. To Alter the Shape of a Portion of the Collar or Side of a Crown. — Slip the crown over the point of an anvil, or the end of a pair of expanders, or a small round-handled instrument held in a vise, and then tap the part to be altered with the flat end of a riveting hammer to the form desired. To Deepen the Cusps. — Trim a piece of wood to the form shown in Fig. 198, rest the neck on a flat surface and press the Avood between the cusps. Fig. 198. Fig. 199. Fig. 200. 2^0 point, lengthen, or narrow in appearance the labial cusp of an upper bicuspid crown, gently tap the gold on each side of the labial cusp toward the point at the angle shown in Fig. 199. To remove the indentation between the cusps and thus flatten the whole grinding-surface, introduce inside the crown a flat- 'ended piece of wood the size of the crown and press downward as shown in Fig. 200. Strengthening Seamless Gold Contour Crowns. — Additional strength and stiffness can be given to seamless gold crowns, when desired, in several ways., The liability of melting the gold which forms the side of the crown in the operation has, with some, been the principal objection to their use. This, however, can be avoided. When the crown has been properly adjusted, dampen the inner surface with a piece of wet cotton on the point of an instrument; place in the interior a quantity of fluxed solder filings (solder filings mixed with Parr's flux or pulverized vitrified borax) ; place ooIjD sk am less coyroLR crowns. 107 the finger over the open end of the crown, invert, and shake well. A portion of the solder filings will adhere evenly all over the wet surface. The surplus is allowed to drop out by removing the finger. Then gradually and uniformly heat the crown by holding it with tweezers in an alcoJiol flame until the solder fuses, Avhen it will flow evenly over the surface of the gold without materially altering the general form. The crown should be held in such a position that a full view of the interior is presented and the melt- ing of the solder rendered visible, which will occur at a red heat. An extra quantity of the solder filings can be placed in tne interior of the cusps with a spoon-shaped excavator to additionally fill or strengthen them if found necessary. When a Bunsen gas flame is used instead of an alcohol flame, the gold must not be brought above a dull red heat. The grind- ing-surface and sides of the crown might be first coated with whit- ing as a safeguard. This is easily done by dipping the crown into a cream-like mixture of whiting just before inserting it in the flame. The moisture in the whiting should be first slowly evapor- ated by heating up gradually. Great care must be exercised in the use of a gas flame to avoid melting the crown. The cro^'vai should be watched, and instantly removed as soon as the solder fuses and flows.-*- If too much solder has been applied at any point, it can be trimmed and smoothed with corundum melted on to an old engine bur-point. Always boil the crown in acid to remove the flux. The removal of flux from the inner surface of the crown is abso- lutely necessary if you intend to use it in bridge-work, as solder will have to be melted on the outside. To repair a hole melted in any kind of a gold crown, place a piece of soft wax in the aperture, on the outside of the crown, adapt on the inside close against the gold a piece of platinum foil, somewhat larger than the aperture, so that it will adhere to the wax. Fill the interior of the crown with investing material, and flow a little solder over the surface of the platinum, and gold on the outside of the crown. Gold seamless crowns can also be strengthened or filled wich 1 18-carat gold plate can be molted in the "Evans Crowns" as safely as solder if heated up slowly. 108 ARTIFICIAL CROWN- AND BRIDGE-WORK. Fig. 201. solder, or even 18- or 20-carat gold plate, by investing the outside surface in plaster and marble-diist (Fig. 201), and then with a small flame of the carbo-oxyhydrogen blow-pipe, not over one- half 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 even with a thin lining of platinum, can be soldered by either method with little danger of being melted. Another method to thicken the grinding-sur- face is: Scratch the inside surface of the gold cusp and pack evenly against it freshly annealed pellets of gold with a sharp plugger. The gold will adhere, and when burnished with a revolv- ing agate point will form solid gold cusps. If desired, the gold foil can be even fused in the cusps, after being packed, by heating up slowly in a Bunsen flame, or a partich? of solder filings can be melted •over it. Supporting the Croivn. — In crowning teeth with living pulps there is sufficient of the natural crown present to afford 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 which will afford secure support and attachment to the artificial crown, and facilitate its adjustment. (See "Special Prepa- ration of Badly Decayed Teeth or Roots," page 38.) In many cases the required support for the crown •can be secured by means of a screw (Fig. 202). A How screw or post of silver wire is inserted in the root-canal A (see page 47). 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 chamois and the mercury pressed out with a pair of pliers until it is in the condition termed "dry" will adhere to the gold without affecting it. The amalgam is first placed in the crown slightly in excess of the amount required, and the crown adjusted, removed, and the surplus scraped out. Fig. 202. OOLD SKAMLKSS (JO^T'HJIi C'UOUWS. 1Q9 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. (For process of cemen- tation, 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 natural crown to indent the amalgam as above described, and then ce- menting 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 gold of the crown is apt to wear through in places and expose the amalgam. Fig. 203. Fig. 204. Fig. 205. To Securely Attach a Croivn. — If the tooth is short, and the occlusion of a character requiring the reduction of the collar to such a degree as to suggest insecurity when the crown is ce- mented, a barbed or headed pin, which will anchor in the natural crown or root, should be soldered in the center of the gold crown, as shown in Fig. 203. This is done by passing the pin through a hole drilled in the occluding surface of the crown, Avhich is then adjusted in the mouth, removed, invested, and the pin soldered from the outside. If the pin is tapered and fitted tightly to the hole (Fig. 204), the soldering can be accomplished without in- vesting, by holding the crown and pin with solder in position in an alcohol flame. To Alter a Gold Crown to the Exact Form of any Correspond- ing Natural One. — In a case having nearly all the natural teeth present, in which the occluding surface and sides differ in shape from the form of the gold crown, to such an extent as to inter- fere with its adjustment, a die of the natural crown should be 110 ARTIFJCIAL CROWN- AND BRIDGE-WORK. made of fusible metal (Melotte's Fusible Alloy ,^ — see article on "Molds and Dies"), and with it the interior of the gold crown should be altered in shape sufficiently to receive the natural crown, by resting the occluding surface of the gold crown on a folded napkin and gently tapping the die into it. By this means a ready- made gold crown is quickly altered to the exact shape of any tooth and is qualified to meet all requirements. Fig. 205 represents the typical molar crown cemented in posi- tion. The advantages of seamless contour crowns are, that they rep- resent 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. CHAPTER IX. .SPECIAL FORMS OF GOLD OJIOWNS WITH I'OK("ELAIN FRONTS. PORCELAIN AND GOLD CROWN WITHOUT A COLLAR, AND PARTIAL COLLAR CROWNS. 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 porcelain crown (Fig, 206). The root-canal is then uniformly enlarged a reasonable distance up, with a drill which will closely fit the open- ing. Into the canal, gauging its full diameter, is fitted a piece Fi(i. 206. Fig. 207. CD Fui. 208. Fif,. 209. Fig. 210. of iridio-platinum Avire, tapered off to a point, so that by intro- ducing it far up the canal greater strength can be obtained, and the root rendered less liable to longitudinal fracture from pressure in a forward direction. A piece of platinum plate, a trifle larger than the end of the root, of about 'No. 30 U. S. standard gauge, with a hole punched in its center, is then slipped on the post, which it must fit tightly (Fig. 207). "When the post is adjusted firmly in the canal, the platinum plate is pressed down on the root, and burnished into the orifice of the canal around the post. When the post is Avithdrawn from the root, the platinum will adhere to it, if fitted closely, with- in 112 ARTIFICIAL GROWN- AND BRIDGE-WORK. 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 bur- nished on the root (Fig. 208). Sometimes around the palatal portion of the root the platinum may be slightly burnished 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, as described on page 85... The whole is then removed, invested, and soldered with gold, Avhich should be melted in at the base 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 Avith gutta-percha or oxyphosphate cement (Fig. 209). Dr. F. T. Van AVoert, of Brooklyn, IN". Y., in constructing Fig. 211. crowiis without collars, shapes the end of the root, and adapts the cap as shown in Fig. 210. A The slant given to the palatal side aids the root ■^S to resist force in a forward direction. Partial Collar C rowns.—T\\e advantages of a collar can in a great measure be given this form of crown by the addition of a metal flange, encir- cling the palatal section of the root, as shown in Fig. 211. A piece of gold or platinum, similar in shape to that shown at A, is formed and fitted to the crown, fixed in position on the crown with wax, and adjusted in the mouth, removed, invested, and sol- dered. After finishing, the metal flange is burnished against the root before the crown is cemented. Dr. T. F. Chupein's method to form a partial collar cap for a root is: Cut a strip of platinum of about jSTo. 32, or gold plate of ISTo. 30 gauge to the shape shown in Fig. 212; for instance, for an incisor. Bend the metal to the form illustrated in Fig. 213. Place the collar on the root with the broad portion at the labial side. Grasp the ends with pliers and draw the metal tightly to- gether against the sides. Remove and solder the ends together (Fig. 214). Trim the edge of the collar to the surface of the root. Solder on a thin piece of platinum plate to form the cap (Fig. 215), aor/D <;it()\v.\s with I'ohci'j.ms fho.xts. 113 and remove the surplus plate and projecting ends and the labial section of the collar (Fig. 216). The cap is then ready to have the post fitted and soldered to it in position (Fig. 217). Fig. 212. Fig. 213. Fig. 214. Fig. 215. Fig. 216. Fig. 217. Post and Dish Method. — Ready-made posts corresponding in size to the Ottolengui reamers, Fig. 72, with disks of platinum, can be used to facilitate the construction of crowns of this style. The posts are illustrated in Fig. 220. A disk of platinum with a perforated depression in which a little gold has been melted is shov»ni in Figs. 221 and 222. The method is as follows: Shape the surface of the end of the root as shown laterally in Fig. 218. Trim the approximal and palatal sides of the end of the root, as illustrated in Fig. 219, but leave the labial side A, intact. Fig. 218. Enlarge and ream the root-canal with Ottolengui root-canal reamers, shown in Fig. 72, to the proper depth, first using the smallest size, and if necessary the larger sizes afterward. -Select a post (Fig. 220) corresponding in number to that of the reamer used. Seize the large end of the post with the points of the pliers and fit the post to the canal. Move the post up and 9 114 ARTIFICIAL CROWN- AND BRIDGE-WORK. down — but do not twist — a few times in the canal, and the slight- est discrepancy that may exist respecting size will be instantly re- moved. Grasp the post when fitted in the canal with the pliers, having the points close to the surface of the end of the root. Remove the post without moving the position of the pliers. Screw the post into the hole in the depression of the platinum disk, shown in Fig, 221 and in section in Fig. 222, up to the points of the pliers, thus giving the post its position in the disk. Bend the sides of the disk downward, as shown in Fig. 223, and adjust the post in the canal to determine their relative posi- tions. By twisting the post, changes of its position in the disk may be effected. Fig. 220. Fig. 221. Fig. 222. Fig. 223. o The orifice of the canal of the root should be slightly enlarged with a round bur to allow the depression of the disk to fit within it. Press the post firmly upward in the root-canal to assure that, its original position is not interfered with by the disk. Remove the post and disk, the disk retaining its position on the post. Unite post and disk by holding them in a Bunsen gas- flame until the pure gold in the depression is fused. No flux is necessary, as sufficient remains from the fusion of the gold in the depression. Fig. 224 Place the post and disk on the root, and press and mal- let the platinum to it with a large flat plugger, which,, owing to the rigidity of the post in the canal, will ac- curately outline the form of the end of the root on the platinum. Remove and slit the platinum at two points between the palatal and approximal sides to the outline of the end of the root as shown in Fig. 224, at A and B, and bend the platinum over with the pliers to embrace the approximal sides of the root. MOUSTISd THE I'OnCELMS FROyT. 115 Again j^lace the post and cap on the root, and closely fit the side flaps, with the aid of foot-shaped condensers and burnishers. jSText bring the palatal flap down to position. Frequent removals and annealings are necessary during the process, which should include the final trimming of the edge of the platinum, smooth- ing with a corundum-point, and then an annealing and all-round burnishing of the cap to the root. Cut off the end of the post above the cap with a corundum-disk and level mth a wheel. The cap can now be invested and the seams soldered, or this can be done in the soldering on of the porcelain front. MOUNTING THE PORCELAIN FRONT. At the cervico-labial section the porcelain can rest on the platinum, or the platinum can be trimmed, so that the front edge of the porcelain may be fitted against the root, and cover it. (See Fig. 225.) The projecting end of the post should also be re- moved l^y first notching with a disk, leaving it a little flush at the Tig. 225. Fig. 220. Fig. 227. palatal side. The porcelain front, which should be a cross-pin plate tooth, is ground and closely fitted to the surface of the root or metal, as may be, at the cervico-labial section under the edge of the gum, but a properly shaped space opening toward the palatal side is left between it and the surface of the cap. To so shape the porcelain simplifies the fitting of the cervical section. The space between the cap and the porcelain is also easier filled in the soldering. To the porcelain front at the part B, Fig. 226, a piece of very thin platinum foil is shaped, the porcelain heated^ the part veneered with a mere film of resin and wax, and by pressure with napkin or cotton the platinum foil is attached thereto. The rest of the porcelain is then backed with thin plati- num plate (about ISTo. 34 gauge). The platinum is left slightly 116 ARTIFICIAL CROWN- AND BRIDGE-WORK. extending over the incisive edge, and the porcelain front is waxed in position on the cap. Fig. 225 shows the crown waxed up ready for investment.- 3Vax in fnll quantity must be extended over the collar to its edge, in the seams, and between the porcelain and the cap at every point solder is to flow (the writer uses Parr's fluxed wax). Fig. 227 shows the invested crown with the wax removed. In trim- ming the investment the material must not be removed from over the collar lower than the line of the surface of the cap, nor in such a manner that the platinum turn-over edges are exposed to the direct force of the flame. Even though the collar is not exposed, the s.older will flow over the outer surface of the plati- num just where it is wanted and where wax has been applied, and all the parts will become united. The investment must be slightly raised at one end and heated up under its base with the full flame of a gas blow-pipe thrown in the direction indicated by the arrow in Fig. 227. Heat thus applied will cause the solder to flow downward by gravitation and fill the interstices in all parts of the investment as though it were an ingot. The best way is to apply solder a little at a time until the deep parts are filled. The flame is withdrawn for an instant, and with a small pointed flame and more solder the backing contoured. As plati- num forms the cap and backing, the soldering can be conducted without fear of accidentally fusing those parts. Unless the sol- dering is conducted as described, the two seams of the cap should be previously soldered. THE PARR CROWN. 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. For use in crown- and bridge-work the outer cap may be made with a band which half encircles the inner- cap, and tapers off from the palatal to the labial section, as illustrated in Fig. 230. The cap on the root is cemented with oxyphosphate, and the post and outer cap with gutta-percha. The root is prepared, banded, and capped without a pin, the same as for a gold collar crown (A, Fig. 228). A hole is made in the cap, and a post fitted in the canal. A piece of gold plate. 77//-; LKEcn cnows. 117 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 root, Pig. 228. Fk;. 229. Fig. 230. and burnished, without a collar, around the post, form- \ ,vw ing an outside cap ; the pin and the outer cap are then re- \w moved 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. 229. THE LEECH CROWN. Fig. 2.S1. Dr. Leech's crown is thns described by Dr. J. E. Dexter:' "A method devised by Dr. H. Iv. Leech, of Philadelphia, shown in Fig. 231, and described in the Dental Cosmos for April, 1879, is as follows: The root is drilled out to a depth of about three- eighths of an inch in diameter of about 'No. 16, standard (American) wire gauge^ the bottom of the hole being flared or enlarged, and the canal above filled with gutta-percha. A gold tube is made to fit the hole accurately and project sufiiciently for convenience of handling, and is sol- dered through a hole in a gold 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. ri i>-4 Denial Cosi May, 1883. 118 ARTIFICIAL CROWN- AND BRIDGE-WORK. gold being flowed onto the plate and backing and around the projecting tube to form the palatal contour, and the tube cut off flush with the latter. We now have a plate tooth, gold backed, with a tube-pivot, the orifice of which opens on the palatal aspect of our tooth. The root-end of the tube is now slit perpendicularly in three or four places, for about two-thirds of its length, a thin sheet of warmed gutta-percha is placed on the base of the crown around the tube, and the whole is pushed securely to place. ISTow pack gold or tin into the tube, condensing the hottom portions so that the slit end will spread and tightly fill the flared end of the hole in the 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 being easily detached. THE PERRY CROWN. Dr. Safford G. Perry, of jSTew York, employs a porcelain crown in combination with a capped root. A bicuspid will be taken as a typical case to illustrate Dr. Perry's ' _,,.,^ method. The end of the root, by trim- /!% / \ ming the edge, is given the tapering form \ shown at A, Fig. 232. The collar (B) is 1 made very narrow. A cap made of plati- I..D num soldered with pure gold is fitted on the [ \ collar, and a post or posts fitted in the root J and through the cap. Enough of the post is allowed to extend beyond the cap to at- tach and firmly retain the porcelain crown (C). A suitable Ilowland-Perry porcelain (see page 49) crown (C, Fig. 232) is ground and fitted in proper position on the cap. This operation is facilitated by perforating a disk of marking- paper with the posts and adjusting it on the cap. Then, as the crown is placed on the cap and pressed against it, points which prevent perfect adjustment are marked on the porcelain. By this means a close joint is easily secured. The edge of the porce- lain should be fitted under the free margin of the gum, especially at the cervico-palatal part. The jDorcelain crown is next set over the projecting pins, and cemented to the cap with oxyphosphate. THE PERRV fJROWX. 1^9 The advantage of this method is, that the root being slightly tapered, the collar can be made to fit absolutely, while the excess of oxyphosphate is gotten rid of through the vent-holes, instead of being squeezed out around the edge of the collar. The edge of the collar being made to a knife-edge, can be properly bur- nished before the crown is placed, so that it will not irritate the gum or make a shelf. The crown covers the cap, and can usually be ground and fitted so as to entirely hide any exposed portion of the collar, the junction of which with the cap should be trimmed and then rounded with a burnisher, to give a form which will better meet the interior of the porcelain cap or crown. The por- celain can be replaced at any time in case of fracture without disturbing the cap on the root. Easy repair, simplicity of con- struction, and artistic result, are the special features of this crown. CHAPTER X. CEOWNING FEACTURED TEETH AND EOOTS— CEOWNING- MOLAE EOOTS DECAYED APAET AT BIFUECATION— CEOWN- ING IN CASES OF lEEEGULAEITY. The crowning of fractured teetli 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. By this is meant a fracture extending lengthwise through the crown or what remains of it, and along the root or roots. Foreign substances having been removed from within and around the parts, the crevice of the fracture is syringed thoroughly with tepid water and then with peroxid of hydrogen. The frarctured parts of the root are then drawn together with waxed floss silk. Fig. 233. p^ggg(j g^^ least twice around the tooth, and tied, the ends ® being passed through twice in forming the knot. The pulp-chamber is then prepared, and dovetail slots are drilled across the parts (Fig. 233). If it is suspected that in the preparation any particles of den- tin have invaded the crevice of the fracture, the ligature must be removed, the parts again syringed, and the ligature readjusted. Aromatic sulfuric acid followed by the peroxid can be recom- mended for the final injections. The upper parts of the root- canals are then filled with gutta-percha, or, preferably, with oxy- chlorid of zinc, and the main body of the cavity and the slots with a hard, quick-setting amalgam. A collar crown should al- ways be used in these cases. If the form to be used has a post, a short, small tube of gold or platinum should be set in the amal- gam in proper position to receive it. At the next visit of the patient the ligature is removed and the parts carefully prepared 120 viiowNiNd Fii.\cri:RED Tiiiyrii and routs. 121 for crowning. Tlie circumference of the root is first measured with a wire, a tight-fitting collar constructed, and the crown then completed in the usual manner. The crown may be favored by leaving a slight space between its occluding surface and the an- tagonizing tooth. 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 is difficult to control. Often subsequent to treatment a septic con- dition 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 described are rarely found with 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 brunt of mastication. In such cases the fracture seldom extends beyond the edge of the alveolar process. The fractured part having been carefully Fia. 234. Fig. 235. removed, a dovetail slot is made in the crown or root, in which gutta-percha is inserted for a day and the membrane of the gum pressed back, so as to fully expose the 'surface and margins of the fracture. The form of the neck is then in a measure restored with amalgam, which, when hard, is polished (Figs. 234 and 235). The tooth or root is then crowned, the mode of operation being the same as in any other case. 122 ARTIFICIAL CROWN- AND BRIDGE-WORK. PERFORATION OF A SIDE-WALL OF A ROOT-CANAL OR OF THE DENTIN AT THE BIFURCATION OF THE ROOTS. Extensive perforation bj decay in these locations below the line of the edge of the alveolar process seldom admits of successful treatment. When the decay is of limited extent, and a very slight perforation has been produced by its thorough removal or by the improper or careless use of a bur, cicatricial tissue may be induced to form over the part by creating and maintaining a sterilized con- dition, and then sealing the cavity. The method of procedure is as follows: First effect steriliza- tion of the dentin and canals. Bathe the perforated part with peroxid of hydrogen. Dry the canal thoroughly. Bathe the edges of the perforation with chloroform. Fit closely over the perforation a small, flat piece of gutta-percha, warmed and applied with a gentle pressure, sufficient only to produce adhesion vdth- out forcing the gutta-percha through. The filling of the canal can then be carefully completed. Oxychlorid of zinc is the most suitable in these cases, as no pressure is required, and a dense anti- septic filling in the roots and over the cap on the perforation is the result. If this method proves unsuccessful and inflammation ensues, the position of the perforation should be carefully calculated, and an artificial fistula should be formed on a direct line with it through the gum and alveolar process (see Fig. 236). Carbolic acid may be used as de- scribed at page 32, to obtund the tissue. The necessary perforation through the alveolar process should be small in diameter, and be made with a drill. Injections can be made outward through the fistula, and the perforation sealed with gutta-percha similarly to the closing of a foramen in cases of alveolar abscess, after having previously filled the canal or canals above the perforation. CROW M NO MOLAR JKjOTS 123 CROWNING MOLAR ROOTS DECAYED APART AT THE BfFURCATION. The roots of a molar decayed apart at the bifurcation can often be crowned serviceably by making a cap for each root separately, Fro. 237. rt]^-^^ and then soldering the sides of the cap together (Fig. 237). Where one root is missing, the other can be crowned singly. DR. FARRAR'S CANTILEVER CROWN. Figs. 238 and 239 represent Dr. J. IST. Farrar's cantilever ■crowns. He describes them as follows: Fig. 238 illustrates a sectional view of three teeth, and an amputated first bicuspid root preserved by a screw, showing the application of the canti- lever crown T P, set upon the decayed second bicuspid and made Fig. 238. Fig. 239. to project over to bridge the space formed by the loss of the first bicuspid, and resting in contact with the cuspid so as to connect the broken line of masticating surfaces and prevent tilting forward of the second bicuspid. The abscessed root here shown was ex- tracted.^ Fig. 239 illustrates the appearance of two molars, the posterior half of one of which is destroyed, showing also the ap- ^Driifal Cusinus, vol. xxvi, No. 3. 124 ARTIFICIAL CROWN- AND BRIDGE-WORK. plication of two cap-crowns, whicli are constructed so as to form a cantilever bridge over the chasm by locking midway in such a manner as to prevent tilting or sliding of surfaces, and at the same time be easily cleansed by a quill or thread. METHODS OF CROWNING IN CASES OF IRREGULARITY. Pig. 240. Fig. 240 shows a method of treat- ing a case of irregularity without de- strojdng the vitality of the pulp. The tooth at B, which stood inside the line of the lower teeth when the mouth was closed, was trimmed, shaped, and capped. To this cap was attached the tooth at A, with an oval-shaped piece of gold that cleared the lower teeth in occlusion. The cap was then cemented to the natural crown. Fig. 241 represents a case of irregularity treated by Dr. Bon- will, 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. 241. do not hesitate to cut off the crown, destroy the pulp, and insert an artificial crown. The crown is brought in the circle and con- nected with the root by a strip of heavy gold plate. The plate is attached to the root with a post or a screw with a nut." CHAPTER XI. PAKTIAL CROWNS. All-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 properly excavated, its orifice is trimmed as uniformly straight or circular as its posi- tion and character will allow, and the edge of the enamel beveled off, tapering toward the center. Deep or extensive undercuts may be filled with oxyphosphate. In the preparation of cavities in the grinding-surface, trimming and cutting away the enamel sliould be confined to that surface. In approximal cavities which reach the grinding-surface, it is advisable to extend them into that surface and bring the gold over and anchor it there, so as to afford greater security against its displacement in mastication. "Where decay extends close to the mar- gin of the gum, if the tooth is trimmed away so that the gold will extend just under its free edge, a recur- rence of decay at that point will be avoided. The bi- cuspid shown in Fig. 242 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 or impression compound, making a plaster model, and then restoring the con- tour 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 mold 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, ISTo. 28 to 30 standard gauge, the exact thickness being governed by the size and nature of the cavity, is struck up to the form and size of the part to be capped. The 125 126 ARTIFICIAL CROWN- AND BRIDGE-WORK. Fig. 243. Fig. 244. gold is then adjusted to the cavity, to the margin of which the- edges are trimmed and burnished to fit close and flush. In th& case of large cavities including a part or the whole of the approxi- mal surface, a plaster model of the tooth and of the empty cavity from an impression taken in wax or impression compound will facilitate and guide the preliminary trimming and shaping of the gold. Two headed pins fixed on the inside of the cap (Fig. 243) are usually sufficient to secure it, but others can be added if the conditions of the case seem to require it. In compound cavities, including one side and the grinding-surf ace, one pin at least should be fixed in the latter portion. Where the grinding and both approximal surfaces are included, a wire should be extended from one side to the other (Fig. 244), but the brace should not touch the bot- tom of the cavity. In pulpless teeth the pin from the upper part of the cap should extend up the canal, which gives great stability in such cases (Fig. 245). 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, as a rule, is preferably used for the cementation of these caps, as it forms a solid and unyielding foundation, and, when properly pro- tected from the fluids of the mouth by a carefully 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 teeth with living pulps show durability of a commendable character. The advantage they possess over Fig. 245. PARTIAL CROWNS. 127 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. Solid Gold Inlays. — The walls of at least the aperture of the cavity are trimmed straight, 'No. 60 platinum foil is adapted to the interior of the cavity and just over its edges by the aid of burnishers and cotton twisted on the end of an instrument, assisted by frequent annealing of the platinum. The matrix thus formed is then filled witli wax, chilled, and removed from the cavity and invested, after which fine gold or 22-carat solder is melted into it. The removal of the matrix from the cavity can be facilitated by the insertion in the wax of a pin or a short piece of wax, which is grasped with tweezers. The plug of gold thus formed is properly trimmed and polished, and cemented in the cavity of the tooth. When completed, it has the appearance of a gold filling. If necessary, the cavity must be previously partly filled with oxyphos- phate or amalgam or shaped with it, to give a better form to per- mit the removal of the shell of platinum foil. Plugs so made can occasionally be utilized as an anchorage for bridge-work. Gold Inlays with Extensive Restoration of Contour. — Dr. W. V-B. Ames's method for approximal cavities in molars and bi- cuspids is as follows: After preparing the cavity as has already been described, an impression is taken in impression compound and a plaster model made. A piece of ISFo. 36 gauge 24-carat gold is shaped first to the cavity on the model and then to the tooth in the mouth. The gold is depressed into Pig 246. any anchorage cavity that has been secured at the occluding surface. To fill this gold matrix 22-carat sol- der is used. For instance, in a case such as is illustrated in Fig. 246, a little of the solder is first melted in the most depressed or anchorage cavity of the occluding surface, by holding the matrix in a Bunsen flame. The matrix is again fitted to the cavity and the operation of fitting and soldering continued until the required contour is obtained. To facilitate the contouring it is well to tack at the proper point a small globule of high-grade solder as shown at A. To and around this globule pack crystal gold or foil to the line or bulge of the required contour, and flow solder in the interstices^ 128 ARTIFICIAL CROWN- AND BRIDGE-WORK. shaping the rest of the inlay at the same time. If considered necessary, the matrix may be invested for this final soldering. 8olid Gold Tips for Abraded Pulpless Front Teeth in prefer- ence to fillings are constructed in the following manner: An open- ing is made through the occluding surface of the crown into the root-canal. A flat post, wide enough to fit closely in the pulp- chaml)er across its greatest diameter, thus tending to prevent any rotary motion of the gold tip, is then formed. A Fig. 24 <. y^^^j ^j^^^^ piece of pure gold plate, say ISTo. 30 LT. S. gauge, is adapted and burnished, with hand-burnishers and Herbst's revolving agate points, into all the irregularities of the abraded surface, and into the orifice of the pulp-cham- ber. The gold is then trimmed flush and even to the edges, and burnished just over them. An opening is next made in this gold cap, and through it the post is inserted in position, fastened with wax, removed and sol- dered to the cap. The post and cap are inserted in position and the gold again burnished to the edges of the tooth and trimmed closely. Wax cement is then placed on the gold and shaped to the exact form of the required gold tip. This is next encircled with a strip of 'No. 60 gold foil fitted against the surface of the wax and extending slightly over on the surface of the enamel of the tooth. This foil is to form a matrix. All is now removed and invested in finely calcined marble-du"st and plaster (see Fig. 247). Pig. 248. '^'^^^ investment is next heated, and 20-carat gold solder melted into the matrix formed by the foil over the cap. The surplus gold is then trimmed to the edge of the abraded surface of the tooth and to the desired form for the tip, and polished. The trimming or polishing of that portion of the tip at or adjacent to the edge which fits against the tooth should always be done with the tip in position on the tooth. When finished, the gold tip is cemented in position with a thin mixture of oxyphosphate. Fig. 248 gives a sectional view of a central incisor tipped in this manner. For Gold Tips in Cases of Living Pidps, two or three small platinum pins, as the case may suggest, are used in holes drilled about the pulp-chamber, in the manner shown in Fig. 249. Three pins are generally placed in upper incisors and two in lower inci- PARTIAL CROWNS. 129 Fio. 249. sors. Three pins should always be used except in very small lower incisors where the space will not permit more than two. The pins should be inserted and soldered in the gold plate one at a time, the plate each time being adjusted to the surface of the tooth. The first pin, if fitted tightly in the hole through the gold, can be soldered without investing, l)ut an investment should be made for the soldering of each subsequent pin, as otherwise the previously soldered l^in or pins are apt to move from position. The least possible quantity of solder should be used on the first two pins. After all the pins have been soldered in position to the gold cap, it is adjusted on the tooth and the gold very carefully biu-nished to its surface and trimmed. A final investment is then made and the required form of the incisive edge added with solder. In a case with a vital pulp, or in a pulpless tooth if the gold tip required is short, the ends of the pins extending above the cap will hold and maintain enough solder in position to give material for proper contouring, without enveloping the wax with a matrix of gold foil as previously described. If three pins are used,. it is very seldom necessary for stability to extend the plate beyond the incisive surface, over the palatal side of the tooth. The partial restoration in gold of a crown having a vital pulp by the methods explained is illustrated in detail by Fig. 250,^ which illustrates the partial restoration of a central incisor and molar with vital pulps. The gold for the incisor, it will be seen, is adapted to the palatal surface and supported by three pins. 1 An experience of several years in the use of gold tips as described shows that they are much to be prefen-ed to tips formed of gold foil, even by the very best operators, the alloyed gold being superior to pure gold in resisting attrition — G. E 10 Fig. 250. 130 ARTIFICIAL CROWN- AND BRIDGE-WORK. Fig. 251. Fig. 251 shows the details of a restoration cast filling for a molar. The contour of the part to be restored was shaped in wax on the cap and pins. The wax was covered with No. 60 gold foil except at one end, and invested in the form of a matrix as shown at A, and in section at B. The wax was removed from the matrix with boiling water through the open end, and the ma- trix was heated and properly filled with gold solder through the same opening. Anoth- er method is to strike up a grinding-surface of pure gold of about No. 34 gauge, adjust on the cap with wax, fit in the mouth to determine oc- clusion, remove, invest, and fill the cavity through the opening with solder. Porcelain and Gold. — The partial restoration with porcelain :and gold of an incisor crown such as is shown in Fig. 252 can be accomplished as here described: The edges of the crown to form the joining with the porcelain are trimmed straight and level, and Fig. 252. Fig. 253. Fig. 254. C-' then polished. A shallow groove is generally formed to advan- tage at A, Fig. 253. A very thin piece of platinum is then adapted to the crown as shown at B, Fig. 254. The pin C is fitted to the root-canal, passing through the platinum. The post and cap of platinum are then attached with wax, removed, invested, and soldered with pure gold. A little of the gold at the same time is fiowed over the cap. The cap and post are then adjusted to the PARTIAL CROWNS. 131 crown, and the cap is trimmed level and burnished closely against the surface of the portion to be restored and into the groove at A, Fig. 253. At this stage of the work, to facilitate the subsequent operations, an impression can be taken which will remove in it the cap, and from this a model can be made. A cross-pin porce- lain tooth is then ground down to a size and shape that will prop- erly restore the part and form an accurate joint with the labial edge of the natural crown. The porcelain ig then backed, cemented to the cap, removed, and soldered with 20-carat solder. The partial crown when properly finished is cemented in position with oxv- phosphate. Fig. 255. Fifi. 256. Fig. 257. In a case such as is represented in Fig. 255 the cap is shaped to the surface of the dentin and enamel at A, and over its palatal edge, and the backing on the porcelain is extended out over the palatal edges of the enamel at B. The two sections of the plati- num are united in the soldering. Fig. 256 illustrates a fractured central incisor in which the pulp was not exposed, restored with porcelain by Dr. J. Bond Littig. The cap to the fractured part was fastened by three small pins as shown in Fig. 257, which illustrates the details of the con- struction. "Where the piece broken off is so narrow that the porcelain tooth cannot be ground to fit in the ordinary way, without cut- ting out the pins," Dr. Littig describes his method as follows: "First cut a groove in the end of the broken tooth, making slight undercuts. The pins of a suitable porcelain tooth are bent out- ward, and the ends flattened. The porcelain is then ground away from both ends, until it is made as narrow as the natural tooth is 132 ARTIFICIAL CROWN- AND BRIDGE-WORK. thick or nearly so. The piece is fitted to the end of the tooth by placing the pins in the groove. If the joint is not good, grind away from either tooth or porcelain nntil it is perfect. Then set the piece with zinc phosphate, and after it has become hard, grind Fig. 258. Fig. 259. Fig. 260. the tip to shape in the month, and polish with moosehide disk and pnmice-stone. Fig. 258 illnstrates the second method; the gronnd porcelain tip, prepared crown, and restored tooth being shown separately."-^ Figs. 259 and 260 illnstrate a case in which the contour of an incisor tooth was restored by Dr. W. F. Litch's pin-and-plate pro- cess. Fig. 259 shows the palatal as- pect of the tooth, in which the open- ings for two retaining pins were drilled, the openings being made quite small. In Fig. 260 is seen the por- celain tip attached to the plate and ready for mounting. The two retain- ing-pins will be observed soldered to the plate. In this case the cervical margin of the natural tooth was made level to afford a secure resting-place for the porcelain tip. 1 The partial restoration of teeth with porcelain is explained in the chapter on "Porcelain Dental Art." CIIAPTEK XII. FINISHING AND POLISHING— PROCESS OF CEMENTATION. FINISHING AND POLISHING CROWN-WORK. The finishing should be done with small corundum or Gem 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. Gem wheels may be used dry when desired. This is an advantage in trimming certain parts of the metal, as corundum must be kept wet. In the final finishing use fine pumice with leather polishing-wheels 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 trim- ming the collar off to a fine edge where it fits under the gum, so that the seam of the union with the root will be imperceptible. 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 gold 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 effected is the same in principle, that is, to form with an insoluble material a solid, substantial, and im- pervious union l>etween the natural tooth or root presented and the artificial crown. OXYPHOSPHATE OF ZINC. As a cement for this purpose, the plastic oxyphosphate of zinc is generally preferred, and it is in many respects one of the most suitable that has as yet been found. If at all exposed even the best preparations are slowly soluble in the mouth, and the porosity of the compound permits it to absorb gases and fluids and gradually become septic. Exact scientific proportions of the chemical sub- stances of which the cement is composed are essential in its prep- 133 134 ARTIFICIAL CROWN- AND BRIDGE-WORK. aration. The oxid of zinc should have been calcined at a high beat, and then ground to a very fine powder. It should possess the property of being uniformly dense and hard clear through the center, when set, after being mixed thin and formed in a mass. The density of one preparation of oxyphosphate of zinc in com- parison with another can be tested by placing samples of each of the same size, mixed under similar conditions, in red ink. After immersion for one or more weeks the samples can be removed, washed, then cut through the center, and their comparative density determined approximately by the depth of the stain. The setting of the best preparations of pure oxyphosphate of zinc is materially affected by temperature. Thus, a cement which is slow-setting at 40° F. is apt to be quite quick-setting at 80° F. In some of the preparations of cement, an effort is made to remedy this variation by adulterating with various substances, but this tends to increase the solubility of the compound. A standard preparation of cement, answering the requirements previously outlined, should be used in crown- and bridge-work. For all styles of crowns with collars, and for bridge-work depending on crowns of similar construction, the cement should be mixed thin; but for crowns without a ferrule or collar it can be moderately thick. 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 suitable. The surface of the slab must be perfectly clean. The acid and powder should first be separately placed on the glass, the amount of powder being fully equal to the requirements of the acid. A portion of the powder should be drawn over and mixed with the acid, and then more of the powder added, a little at a time, until a suitable consistence is reached, when the surplus powder should be instantly thrown off the slab, and the mixing, which must be rapid and thorough, continued; the consistence should be that of thick cream. It is not a good plan to mix cement excessively thin, and then wait until it becomes thick- ened by the process of setting to a consistence suitable for use. The resulting compound is unnecessarily acid, the overplus of acidity being proportioned to the excess of acid used over the quantity required, and its character as a cement impaired. On the other hand, if mixed too thick, force is required to bring the crown or cap to position, and the thin edges of collars are liable to INSERTION AND CEMENTATION. 135 be sprung from the sides of the roots; neither will the cement ad- here with such tenacity to the parts as when mixed at a proper consistence. If the slab is placed on a towel which has been saturated with ice-water, the cold will retard the setting, which is quite an advantage in many cases. In this respect the side of a square bottle filled with ice-water and well corked is preferable to a slab. The parts to be crowned should be previously syringed with water and peroxid of hydrogen if the gum-margins are slightly lacerated, then protected by a napkin, bathed with alcohol ap- plied on cotton with tweezers, and dried with absorbent cotton or bibulous paper. A rope of twisted absorbent cotton may be wound around each natural crown and pressed close against the gum, with the ends twisted together at the labial side so that the cotton can be easily seized and instantly removed at the moment the cement is ready. Each cap or crown, which should have been thoroughly dried, is first filled 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 the artificial crown or bridge immediately adjusted in position. In many cases it is best to quickly remove the napkin and close Fig. 261. the mouth to insure the occlusion of the teeth, and then open the mouth and replace the napkin. The crown or bridge should be held under a slight pressure until the cement has set. For this purpose a piece of wood notched on the end, or a crown- driver^ (Fig. 261), can be used. With bicuspids or molar crowns and in bridge-work, however, it is better in most cases to occlude the teeth, and keep them in position under a steady pressure until 1 This instrument can be used to fit a tight collar or crown. It also has a pull- off attachment which is handy in removing crowns. 136 ARTIFICIAL CliOWN- AND BRIDGE- WORK. the cement sets. Under tliese cireniustances the saliva can reach only the snrplns portion of the cement, and cannot interfere with that nnder the cap or crown. One or two thicknesses of tin foil, placed over the crown as the teeth are occlnded, will slightly favor the length. When the cement has set perfectly hard, the snrplns around the edges should he removed. In collar or shell crowns the ex- treme edges of the gold of the collar or shell should he given a tinal burnishing. Excessive burnishing and force, though, should he avoided, as tending to injure the cement under the collar. Wet floss silk or dental fiber, charged ^vith pumice, should be passed between and around the teeth to remove every particle of the superfluous cement, and Anally the parts should be syringed with tepid water. The patient should be requested to call in a few days, so tliat an examination may he made to see if any particles of the cement were overlooked. C'leansing gently at this time facilitates the healing of the gmu around the collar or neck. Care in these little details tends to prevent that inflamed appearance and reces- sion 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 cro^^^lS should be slightly barbed. By encasing the post with a fllm of gutta-percha it is made easily removable, whicli is a desirable feature in crown- or bridge-work. This is done by warming the crown to a point that will heat the post, and then painting the post with a thin coat of chloro-percha. The heat instantly evaporates the chloro- form, leaving a thin fllm of warm gutta-percha adhering to the post. The crown is then instantly placed on the root and re- moved. This deflnes the relations of the gutta-percha on the post to the walls of the canal, and indicates any slight surplus if present. Cementation with the oxyphosphate completes the operation. At any time, by warming the crown, the thin sheath of gutta-percha is softened and the attachment of the post inay be easily broken. This method of setting the post makes bridge- work, so supported, easily detachable. A -fllm of gutta-percha placed in the grinding-surface of a gold ca]> will also provide a similar advantage in case of a gold crown. The gold cap should be fii'st heated, the gutta-percha inserted, and the cap adjusted and INSERTION AND CEMENTATION. 137 removed and the amount and position of gutta-percha exactly determined. Th6 cementation is then y\o. 262 ■conducted as without the gutta- percha. In all-gold cap-crowns a vent for the escape of air and surplus ce- ment is made by some in the form ■of a small hole, usually in the deepest fissure of the grinding-surface, but it is a practice that is now being gen- erally discarded. When the cement has hardened, the hole must in all cases bo closed with a gold or amal- gam filling. GUTTA-PERCHA. The merits. of gutta-percha for the cementation of crown- and bridge- work are: Gutta-percha is insoluble in the fluids of the mouth, but at any time the work can be removed by the application of suflicient heat to soften it. To be able to remove work thus easily is an advantage that is ap- parent without comment. In com- parison with oxyphosphate, it lacks rigidity, so that its sphere of applica- tion is limited, and there are besides the well-known difficulties which at- tend its manipulation. Ci'owns without Collars. — When gutta-percha is used, heat the crown. Paint the post and the base of the crown, and any recesses in the latter, with a very thin solution of chloro- gutta-percha. The heat instantly evaporates the chloroform, leaving a mere film of gutta-percha tenaciously adhering to the parts. Fill the recess and cover the base 138 ARTIFICIAL CROWN- AND BRIDGE-WORK. crown with a perforated disk of gutta-percha, and press the crown- to position on the root. Let the gutta-percha cool slightly, re- move the crown and trim the surplus from the edges; wipe out the canal with chloroform, dry with cotton and hot-air syringe. J^ext place on the post or in the canal enough gutta-percha to- insure a very slight surplus, heat the crown, and press to place. A crown-setter, as illustrated in Fig. 262, heats the crown and assists in setting with gutta-percha. Heat the copper end suf- ficiently to soften the gutta-percha, and place the grooved end over the crown with the heated copper in contact with the porcelain. Hold the setter against the crown until the gutta-percha becomes soft, when pressure applied to the setter forces the crown with its pin to its proper position. The cooling of the gutta-percha can be hastened by dipping the crown-setter in a tumbler of ice- water and holding it against the tooth until it is cold. When the gutta-percha is cold, the surplus is removed with a warmed sharp instrument, and the edges smoothed by drawing back and forth against them some twisted fibers of cotton or floss silk sat- urated with chloroform. Sometimes it may be desirable to fasten the post with oxyphosphate and join the end of the root and ar- tificial crown with gutta-percha. In such a case the crown should be heated and the gutta-percha, rolled down very thin, placed on the edges to be united in the form of a perforated disk. The crown is then pressed to position in the oxyphosphate placed in the root. The order of the use of these materials should be re- versed where it may be desirable at some future time to easily remove the crown. Collar Crowns with or without Posts. — The crown is heated,, freshly prepared chloro-gutta-percha is painted all over the in- side of the cap and over any post present in successive layers as the chloroform evaporates. The quantity of gutta-percha at first ap- plied should be a little less than will be required to properly cement the cap. The whole crown is next heated to a point sufiicient to cause the gutta-percha to adhere to the metal, but not to burn the gutta-percha. The crown is allowed to cool enough to permit it to be handled and adjusted in position on the tooth or root, and then instantly removed before the gutta-percha cools. The saliva present on the teeth prevents the adhesion of the gutta- percha to the tooth-structure. The inside of the cap is next INSERTION AND CEMENTATION. 139 washed out with water, followed with alcohol, and dried with a hot-air syringe. The gutta-percha on the inside of the cap will show an impression of the natural tooth or root. Points showing a deficiency of gutta-percha are to be filled up with more of the solution in chloroform, or it may be well to use a little of the solid gutta-percha for the purpose. The crown is again heated, adjusted in the mouth, and removed, this being repeated until the cap shows a perfect distribution of the gutta-percha. Any surplus extending from the edges of the cap should be removed. For the permanent insertion the gutta-percha is dried in the same manner as before. The tooth or root is protected with napkins and also dried, and then varnished with an exceed- ingly thin solution of solidified Canada balsam dissolved in chloroform. The crown is next heated and placed on the tooth or root and held in position, either with an instrument or by oc- clusion of the teeth, until the gutta-percha cools. There is usually very little, if any, surplus to remove. If, on close examination^ it should be found that the crown has failed by any means to exactly assume its proper position, a heated crown-setter or the copper bulb of a root-canal drier may be applied, and the crown heated to as much as the patient can bear, which will soften the attachment to allow the crown to be pressed to place. As to the amount of heat that can be tolerated by the patient in the use of gutta-percha, your gauge will be : Any heated crown or bridge that can be held by the fingers of the operator can always be inserted without special discomfort to the patient. Bridge-Worh, — The method of cementing on a single crown just described can also be well applied to some small cases of bridge- work, such as a single cap with an extension bridge of one or two teeth, or a bridge vdth two caps, especially if all or nearly all of the natural crowns of the abutment teeth are present. Large Pieces of Bridge-Work, more especially where the caps cover teeth with considerable of the crov^nis absent, can be ce- mented with gutta-percha more conveniently by the following method: Select a preparation of gutta-percha which softens at a low heat. Place it on a piece of soapstone or on a large granite- ware spoon. Heat up until the gutta-percha becomes so plastic that it can be worked with a spatula. Heat the bridge-work and caps. Coat the inside of the caps with chloro-gutta-percha, and 140 ARTIFICIAL CROWN- AND BRIDGE-WORK. when the chloroform has evaporated place the giitta-percha you have heated with the spatula around in the caps somewhat as you would oxyphosphate cement. Have water boiling in a cup and immerse the bridge in the water, letting it remain for about one- half minute. Kemove with tweezers, dry the exterior with a nap- kin, and immediately adjust in the mouth in position, and then quickly remove it. On removal, the gutta-percha in the caps should be dried as described in the use of chloro-gutta-percha, and more gutta-percha added where required. The boiling and insertion are repeated until a proper quantity of gutta-percha is placed in each cap. The gutta-percha is then again dried, and the caps heated in a flame to a point which will assure the adhesion of the gutta-percha to their inner surfaces. The natural crowns or roots are then varnished with the solution of chloroform and Canada balsam as before described, and when the bridge is at a heat possible to handle, it is permanently placed in position in the mouth and cooled with ice-water from a syringe. Should the bridge be found to have failed to assume its proper position, a heated crown-setter, or the copper bult of a root-canal drier from which the point has been removed, can be applied rapidly from one crown to another until a heat as great as the patient can bear is reached, when the caps can be pressed to place. Another method of heating gold crowns in the mouth is to apply a gas jet about one-eighth of an inch in size to the gold ■caps. This is done by passing the gas through a small brass tube, like the nozzle of a syringe, connected with a rubber tube. Gutta-percha and OxypJiosphate Comhined. — In case of collar crowns, envelop the post with gutta-percha by the use of heat and chloro-gutta-percha as described. After adjusting in the mouth re- move and fill the cap with oxyphosphate cement, at the same time placing a little cement on the post, and bring the crown to place on the root. In setting gold crowns by this method, apply the gutta-percha in the manner described for gutta-percha alone, but in a slightly less quantity than is required, then place the oxy- phosphate in the cap or caps and adjust in position in the mouth. Crowns and bridges mounted in this manner present no special difficulties in removal when desired; for, when the heat applied is sufficient to soften the gutta-percha thoroughly, the oxyphosphate will usually loosen sufficiently to permit removal. INSERTION AND CEMENTATION. 141 AMALGAM. Amalgam is used to some extent to support and retain porce- lain crowns. Its use in connection with the Gates-Bonwill crown is given on page 48. Where it is desirable to use amalgam, Dr. Kirk gives copper amalgam the preference to other kinds as an attachment for the Logan crown to weak or badly-decajed roots. The following is Dr. Kirk's method for the adjustment of Logan and similar classes of crowns, which he has found satisfactory in those extreme cases where there has been much loss of root-struc- ture through the action oi, caries in the pulp-canal, resulting in a large funnel-shaped opening with more or less weakened root- walls. The canal is prepared by removing the softened structure, fill- ing the apex, and making suitable undercuts or roughnesses along its walls, and then filled flush with its orifice with a good grade of copper amalgam softened to a plastic, buttery condition. The apical end of the crown pin is sharpened to a point or hatchet edge as may be most expedient, and placed against the amalgam surface in the root-opening, and the crown at once driven to place in close contact with the root by holding against its morsal (oc- cluding) surface a suitable point mounted in the Bonwill mechani- cal mallet. For this purpose, the blow of the mallet should be considerably increased in intensity beyond that ordinarily used for filling-operations. The point used in the mallet for driving the crown home is best improvised from a porte polisher armed with a hickory point, the use of which avoids chipping the porce- lain. All excess of copper amalgam is by this means driven out between the surfaces of contact of the crown and root in pre- cisely the same manner as occurs in the use of oxyphosphate. An excess should be used in order to be sure of filling all interstices. This method, involving the use of copper amalgam, is advocated only in the class of cases described, for which it possesses the ad- vantage of giving complete support to the root, because of the great strength and insolubility of the material employed. Other amalgams experimented with for this purpose have not been so satisfactory, because of their lack of plasticity, and of the flowing quality which characterizes the coj)per amalgam when subjected to the rapid vibratory percussive force of the mechanical mallet blow. PAET 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. Fig. 263. Fig. 264. Originally, the application and mechanical construction of such dentures was of a most primitive character; and as the attach- ments were simply ligatures or clasps of gold, the teeth were more ornamental than useful. Figs. Fig. 265. 263, 264, and 265 illustrate the antique methods.^ Fig. 263 is an illustration of a specimen of ancient Phoenician dentistry. Fig. 264 is that of one in the Etruscan age, dating about five hundred years b.c. Fig. 265 gives a view of the same denture inverted. ^ See Independent F7xictitioner, vols, vi and vii, "Evidences of Prehistoric Den- tistry," by J. G. Van Marter, CDS., Eome, Italy. Figs. 263, 264, 265, are copies of the illustrations of the specimens, the first of which is represented as being in the museum of the Louvre, Paris, France, and the second in the Corneto Museum, Corneto, Italy. 11 145 146 ARTIFICIAL CROWN- AND BRIDGE-WORK. Dentures constructed on the bridging plan by various methods have been occasionally employed from the earliest days of modern dentistry, though until recent years the system has not obtained general recognition nor been extensively practiced. Dental literature presents bridging operations as described by J. B. Gariot in 1805, C. F. Delabarre in 1820, Dr. S. S. Fitch in 1829, William Imrie in 1834, J. Paterson Clark in 1836, and Dr. W. H. Dwindle in 1856. Figs. 266 and 267 are copies of illustrations in Dr. Fitch's work, published in JSTew York in 1829, and Fig. 268 one from a translation of F. Maury's work in 1843. Tig . 266. ^ W^ ■?■"'! Fig. 267. Fig. 268. Fig. 269. C c a. a, cc o c 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. 269). The sys- tem was also practiced in operations by the late Dr. M. H. "Webb, and is described in his "ISTotes on Operative Dentistry." The facilities ajBForded by the artificial crown-work now in vogue for supporting and securing bridge dentures have caused BRIDGE- WORK. 147 a revival of the system in an improved form, now 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 natural teeth are not abraded by the presence of clasps, the functions of the sense of taste are more perfectly per- formed, 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. The weight of the denture and the strain of mastica- tion are proportionately distributed on the natural teeth, which are better suited to sustain them than the contiguous alveolar sur- faces. Sixth. Its special adaptation to the replacement of single teeth, or of a small number, where bridge-work is usually superior to any other device. Seventh. While 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 perma- nency 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 148 ARTIFICIAL CROWN- AND BRIDGE- WORK. the bridge, as artificial gums cannot properly, in most cases, 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 and comfort of the wearer are often af- fected by these self-cleansing slots under the front teeth. Fourth. The teeth employed as abutments are usually irrep- arably destroyed by the process of crowning. Fifth. If an extensive bridge is made of gold, being immova- ble, it is impossible to keep it perfectly clean, as the metal Avill gradually tarnish in parts out of reach of the brush, and will gather ofi"ensive matter on its surface and in its interstices. Sixth. In cases where it becomes necessary to temporarily re- move the bridge for the purpose of repair, or because of disease in the teeth which support it, the operation is difficult and the bridge is usually injured so as to unfit it for reinsertion. Seventh. 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- nently attached, at no time can any rest be given the abutments or the contiguous parts by its temporary removal. Thus in a piece of bridge-work of fourteen teeth supported by caps or crowns on four natural ones, each one of the natural teeth may have to bear more than three times the strain in supporting the weight of the denture and the force of mastication, 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 usefulness and durability of such work is decidedly limited in character, considering the time, trouble, and great ex- pense attending it. Such are the objections which have been put forth against bridge- work; and yet, whatever may be urged against it, its ad- vantages have won from a majority of the profession, including BRIDGE-WORK. 149 many accepted authorities, an enthusiastic, almost a sensational, 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. With- out doubt it has been, and is still, 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 at- tend all new departures in the arts. CHAPTEE I. CONSTRTJCTION OF BEIDGE-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 collectively, ac- cording to their position and condition of health, should be care- fully 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 posi- tion of the teeth or roots required as foundations for bridges in practice, are as follows: One central root will support two centrals, and if spurs or bars from the sides of the bridge rest upon or are anchored in the ad- joining 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, or with the aid of a central root, will support the six anterior teeth. Oiie 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, Avill support a bridge comprising the arch between them. 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. 150 CONSTRUCTION OF BRIDGE-WORK. 151 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 antagonizing teeth is close and deep, the strain should be relieved by an addi- tional attachment of the bridge to the teeth posterior to the cus- pids. Fro. 270. The preparation of teeth or roots to support a bridge is the same as for ordinary crowns, 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 bridge., Teeth or roots which are to be supplied with porcelain-faced or all-gold cap-crowns are crowned by some one of the methods already described. The roots which are to carry porcelain-faced crowns can be so crowned or only capped, the posts being soldered and allowed to project a short distance beyond the caps. The case represented in Mg. 270 will be used to illustrate the construction of a piece of bridge-work in all its details. The abut- ments, or supports, consist of the right second molar capped with an all-gold crown, constructed in sections by first forming the col- lar and then soldering on the cap (see page 87), the two cuspid roots capped for collar crowns with porcelain fronts (see page 79), 152 ARTIFICIAL CROWN- AND BRIDGE-WORK. and the left first molar, which will afford anchorage to a bar on that side of the bridge (Fig. 271). 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. 272). If the tooth is not de- cayed, it can be first opened up with a rubber and corundum disk. The shaping of the slot is best accomplished with fissure-burs. With the crowns and caps in position, an impression and articula- tion of the case are then taken with plaster^ slightly colored with carmine, to which is added a little sulfate of potassium, less than the proportion of salt generally used, which causes it to set quickly. Fig. 271. Fig. 272. The plaster is mixed moderately thick, and with the aid of a spoon or rolled in a mass in the fingers, which should be wet to prevent adhesion of the plaster, is 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 the plaster carefully re- moved, the pieces being adjusted together should it break. The crowns and caps (the latter held more firmly by the protruding ends of the pins) are generally removed in the impression; if not, they should be transferred from the mouth to it. The plaster is then varnished and oiled, and on the side containing the crowns ^Impression compound is used to some extent for this purpose instead of plas- ter, but in the author's opinion cannot be recommended as suitable. CONSTRUCTION (>F HRIDHE-WORK. 153 a model is run, composed of equal parts of calcined marble-dust and plaster, to which a little sulfate of potassium is added. AVhen the model has set, it is mounted with plaster on an articulator, and the other side of the colored plaster impression giving the articu- lation is run with plaster and the opposite section of the articulator adjusted. AVhen the impression plaster is removed fan operation which is greatly facilitated by its having been colored with car- mine), a correct model and articulation of the case will be found, with the crowns and caps in exact position as in the mouth (Fig. 278). Fig. 273. Another method is to fii'st take the articulation in wax vrith the caps and crowns in position in the mouth, and then the impression in an impression-tray ^\ix\l plaster, and. make a model and articula- tion from them in the usual manner. Dr. Melotte's method is to place a piece of impression com- pound in the space between the crowns to be occupied by a bridge, and occlude the teeth. The compound is then chilled, removed, trimmed, and readjusted until it accurately fits the space, when it is placed in position and an impression is taken with plaster. TThen the impression is removed, iron pins to act as dowels are placed in the portions representing the natural teeth, and then several pieces of fusible metal, by a few puffs of flame from the blow-pipe, are melted in around the pins. The rest of the impres- sion is then run with plaster and marljle-dust in the usual manner. This forms a plaster model on which the natural teeth are rep- 154 ARTIFICIAL CROWN- AND BRIDGE-WORK. resented in metal. These metal teeth are to be removed before- investing in soldering the bridge. An impression of the occlud- ing teeth is taken in plaster, and the entire impression run with fusible metal. When the plaster impression is removed from the model of the bridge, the piece of impression compound betv^een the- crowns is to be left in position, and the metallic model of the Occluding teeth fitted in position, guided by the indentations of the occluding teeth in the compound, and the case mounted on an ar- ticulator. The principal object of this method is to avoid fracture - of forms of natural teeth, both in removal from impressions and ini the construction of the bridge-work. The pins protruding from the caps on the model are next cut off short. Teeth are selected, — ordinary cross-pin plate teeth for the incisors and cuspids, and partial teeth, representing 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. 274). 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 upper edge of the- teeth shall press lightly on the- gum. Those which are in- tended to form the fronts of the caps on the cuspid roots should be adjusted in the ordi- nary manner for single crowns.. To determine the proper posi- tions 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 quantity to hold them in position, thus forming a matrix, or, the matrix can be formed of plaster and entirely removed before investing for soldering. The wax is then removed, exposing the palatal portion, and permitting the forms CONSTRUCTION OF BRIDGE-WORK. 156 and position of the teeth to be studied (Fig. 275). The porcelain teeth or fronts, with the exception of fronts for the roots capped^ are then removed from their investment, and the base ground from a line on the palatal side below the pins, straight to the labio-cervi- cal edge (A and B, Fig. 275). This is to form the self-cleansing spaces. The incisors are then backed, using either 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 i& Shows "dummies" in various stages of construction. A, central incisor, and B, bicuspid,, ready for metallic backing. C is a central backed. D, D, D, porcelain fronts as they appear on insertion after the process of backing, capping, and soldering. secured if the backing extends only to the edge of the self -cleans^ ing space, and the porcelain is polished, as its surface is superior in cleanliness to that of gold. If the platinum backing used is sO' exceedingly thin as to be of the nature of foil, it is advisable to rivet a small piece of gold plate over it on the back of the tooth, to insure against melting the platinum off the porcelain with the- gold, which is apt to occur if a pointed flame is directed against it. The cuspids are backed in the manner described for collar crowns. 156 ARTIFICIAL CROWN- AND BRIDGE-WORK. The bicuspid and molar porcelain fronts, their tips being ground off (A, Fig. 276), are lined in a similar manner. A cap of pure gold or gold lined with platinum, representing the grinding-surf ace of each tooth, is struck up as described and illustrated in the con- struction of gold crowns (see page 88), and the Concave portion filled bj melting in scraps of 20-carat gold plate or solder. The surface is then ground smooth (B), and closelj fitted to the tip of the porcelain front to form the occluding surface in accordance Fig. 276. Fig. 277. 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 very thin gold plate, platinum, or IsTo. 60 gold foil, or mica (C), cut and fitted to the sides, over which they should extend slightly, will retain the gold in position when melted, but are seldom necessary. The tooth is next invested, leaving the back open, presenting the form of a pocket (Fig. 'ill)} Fig. 278. Another method of constructing bicuspid and molar dummies is to fit the cap to the labial edge of the porcelain front, back the porcelain with thin platinum, extending the backing over and between the porcelain and cap, and then filling in the space with gold in soldering, as shown at A, in Fig. 278. The bar intended to be anchored in the slot cut in the molar on the left side is made of iridio-platinum wire, about ~So. 15 U. S. standard gauge, with the end shaped as shown in Fig. 279, and fastened with wax to the tooth and cap, ^^^ 279. and adjusted in the mouth to obtain accuracy of posi- tion before soldering. The advisability of constructing bridge-work with what are termed self -cleansing spaces is not favorably ^See the Hollingsworth System for description of method of swaging grinding- surfaces of several crowns and dummies on one piece of plate. CONSTRUCTION OF BRIDGE-WORK. 157 accepted of late by many practitioners. Instead, the following method is adopted: Porcelain fronts thicker in the line from the labial to palatal side than those most commonh^ nsed are selected. The base or cervical section of the porcelain is ground and fitted to the alveolar ridge very accurately. The fronts are then waxed in position, and with a fine-pointed lead-pencil a line is drawn ac- curately around the base of each porcelain front on the model. The fronts are then removed, and with a suitable scraper the plaster under, and only under, the base of each is removed uni- formly the thickness of cardboard. The porcelains are then fitted back in position with the bases in the indentations. The work is then proceeded with in the usual manner. When the bridge is finished and inserted, the base of each porcelain will uniformly indent the gum to the depth the plaster was removed, and the con- formation will also exclude particles of food and present a much Fig. 280. Fig. 281. more agreeable shape to the tongue and a better appearance for the patient. The shape a bicuspid dummy would assume, con- structed as described, is shown in Fig. 278.^ The teeth forming the bridge between the crowns are called "dummies." In the construction, of dummies it is well to favor the occluding surface by shaping it a trifle narroiver from labial to palatal side than the corresponding natural tooth was. All the porcelain teeth or fronts can be invested at the same time, including the incisors and porcelain fronts to the cuspid crowns, as shown in Fig. 280. In the soldering, if the backing is done vnth platinum, and the occluding surface of the bicuspids and molars made with 24-carat gold or gold lined with platinum, 18 or 20-carat gold plate or hard-flowing solder (see page 79) may ^ The author, at present, in his own practice constructs most of his worlc in this manner. 158 ARTIFICIAL CROWN- AND BRIDGE-WORK. be melted into the pockets formed by the cap and side pieces to fill out to the line at A, Fig. 281, and flowed over the backings of the incisors and cuspid fronts in sufficient quantity to shape them as shown at B, Fig. 282. When the backing and occluding surfaces are made of 18 or 20-carat gold plate, 18 or 20-carat solder and small pieces or filings of gold plate should be used instead. After the soldering and removal of the borax with acid, the metal of each tooth is then, when it is easily done, very carefully trimmed and shaped with corundum-wheels and points. Fig. 282. Fig. 283. The teeth are next placed in their relative positions on the model as shown at D, D, D, Fig. 275, and attached to one another with wax in exactly the relation and only where they are to be united with the gold solder. The model is then detached from the articulator, trimmed down as much as possible in size, and additional investing material, composed of two parts marble-dust and one of plaster, or one part plaster, one marble-dust, and one common white sand, applied until all of the bridge is covered ex- cept the space along the backings and crowns where they are to be united in the soldering. To prevent fracture during the process of soldering, which might readily occur from contraction in so large an investment, an iron wire or a narrow horse-shoe shaped strip of sheet iron should be placed in the investment so as to en- circle the teeth and crowns about one-fourth of an inch from their exterior surface (Fig. 283). In any spacings between the back- CONSTRUCTION OF BRIDGE- WORK. 159 ings pieces of gold or platinum plate or wire, about one-eighth of an inch long, are placed lengthwise, and the joints well soldered. When the backings have been soldered with gold plate or hard- flowing solder, 20-carat solder may be used. If the backings were .done with 20-carat solder, an easy-flowing 18-carat solder should ibe used. The soldering is best done with a gas blow-pipe on a ipiece of charcoal with a concave depression (see chapter on Solder- ing). When the bridge is removed for finishing, the joints of the backings and crowns are finished with corundum-wheels and points .and leather polishing-wheels 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. 284). If the constructive details have been properly per- Fig. 284. formed as described, a finished piece of bridge-work is the re- •sult. In constructing bridge-work many prefer, after the porcelain fronts are backed and the caps forming the occluding surfaces •of the bicuspids and molars are properly adjusted on the model, to invest and do the entire sol- dering at once. When this plan is followed, pieces of gold wire or plate should be laid lengthwise in the slots under the gold caps 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 warping is more apt to occur, and the -finishing of the bridge is not so easily done. In large pieces of work warping may be avoided, whichever method of soldering is adopted, by first removing, in proper posi- tion, the "dummies," and soldering those of each span together. The spans are then replaced in the matrix and soldered to the abutments. Another method much practiced is to construct the bridge in sections, adjust the sections in the mouth, and remove them in an impression-tray, using only sufficient investing material to cover 160 ARTIFICIAL CROWN- AND BRIDGE-WORK. the points of the teeth and crown^ as shown in Fig. 285. The bridge and the investing material are then removed from the im- pression-tray, and more investing material is added to complete the investment. The sections of the bridge to be united are then exposed and soldered together. To enable the investing material to be easily removed from the impression-tray, it is well to melt a film of wax on the interior surface, then cool and serrate the surface of the wax. The plaster will firmly adhere to the wax, but will loosen when the tray is heated. In the case just described, the right and left cuspids and molar sections could be made first,, adjusted in position, the incisors then formed between them, and all soldered together; or, the front section, consisting of the cus- pids and incisors, could be first made, and then the rear exten- sions to the molars added. Fig. 286. 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 (a thin paste of rouge and oil) should be applied inside the cap or caps interfering, 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. Only sufficient investing material to cover the points of the teeth and crowns (Fig. 285) should be used as Fig. 286. CC)NSTRUCTI()N OF JililDd K-WORK. Igl just described in construction of a bridge in sections, more invest- ment material being added after removal, and the sections sol- dered together. When the adjustment of the bridge is accomplished, it can at first be temporarily inserted for a day or two, if desired, which permits it to settle accurately in position. If the bridge is warmed and paraffin to which a little aristol has been added is placed in the caps before inserting, the secretions vdll be better excluded and a septic odor prevented. Burnishing the collars will usually se- cure the bridge; if not, it can be cemented with a little gutta- percha placed in each cap, instead of the paraffin. For its per- manent 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 ce- mented on with oxyphos- phate cement or gutta- percha. The end of the bar is anchored in the slot by either a gold or an amal- gam filling (see chapter on Bar Bridges). Fig. 286 represents the bridge in position. The Construction of Small Pieces of Bridge-work is much sim- plified 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 dummies are then removed together, in an impression-tray filled with investing material. The inside of the tray should be previ- ously oiled or coated with a film of wax with a serrated surface. The impression-tray 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 investment, when set, is then cut away sufficiently to expose the parts that are to be filled in and united together in the pro- 12 162 ARTIFICIAL CROWN- AND BRIDGE-WORK. cess of soldering. Figs. 287, 288, represent cases of bridge-work constructed in this manner. Fig. 287. Fig. 288. In a bridge of two teetli, often a preferable method is to prop- erly adjust crown and dummy tooth cemented with wax in the raouth, carefully remove them in position from the mouth, then invest and solder together. Fig. 289. Fig. 290. CHAPTER II. SPECIAL PROCESSES AND APPLIANCES IN BRIDGE- WORK. 8houldters on Anterior Crowns or Artificial Teeth are sometimes desirable, especially on the superior cuspids at the point of occlu- sion with the lower teeth. A shoulder can be made by 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 wax transversely across the backing in proper position a strip of gold plate as shown in Fig. 289, and then flow in gold to the line A, by specially invest- ing or in the soldering of the bridge. The strip of gold should be extended a iittle beyond both sides of the backing or over the incisive edge of the porcelain to retain it in position in the investment. Solid Porcelain Dummies with Gold Base. — In some cases of bridge- work on the lower jaw, protection of the incising edges and occluding surfaces of dummies with gold renders them noticeable to an extent which is very objectionable to vciawj patients. This can be remedied in bicuspids by forming the occluding surface and the exposed portion of the labial face of the porcelain in the following manner: Select a suitable sized ordinary bicuspid de- signed for vulcanite, and level out the headed portion of the pins by squeezing with pliers. Cut a strip of pure gold about JSTo. 34 gauge, of a size to encircle the tooth and give an excess in length and width of about one-eighth of an inch. Trim the strip to the shape seen at Fig. 291, and punch a hole. A, in one of the corners. Slij) this over the left-hand pin A, Fig. 292, wrap the gold tightly around the porcelain, and bring it over, as shown by the dotted line, on to the right-hand pin marked B. Mark the location of the pin and punch a hole, put the pin through 163 164 ARTIFICIAL CROWN- AND BRIDGE-WORK. tlie hole and bring tlie gold down on tlie porcelain. Outline on the gold enough to expose the porcelain as shown in Fig. Fig. 291. Fig. 292. 293. Eemove the gold and cut out the portion marked. Replace the gold on the tooth, pinch in around the base of the porcelain, Fig 293 ^^^ ^^^ ^^ ^^ excess of length, also the excess at the overlap on a diagonal line so as to make an even joint. Bend the pins, invest and flow solder over pins and seam. When completed you will have a dummy of the form exhibited in Fig. 293, which can be placed in position and attached with solder. Bolid Gold Crowns. — In a close articulation, when the patient prefers strength to appearance, the bicuspids and molars may be made of solid gold. They are constructed by stamping up the cap (A, Fig. 290) representing the grin ding-surface (see page 86), adjusting and cementing to this with wax a piece of plate cut and shaped to form the front and sides (B), the whole being then in- vested and filled in with gold solder, or, if pure gold and platinum 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 exposure of the palatal portion, the crown removed, and cut away to the form re- quired. They are then removed, invested, and filled in with scraps of gold plate and solder. A bar bridge can be made with these seamless crowns by passing an iridio-platinum wire through the crowns before filling in (Fig. 294). A Solid Gold Croivn for a Pulpless Molar, supporting the end of a bar as shown in Fig. 295, is constructed as follows: The natural crown is ground down, banded, capped, and pivoted as SPECIAL PROCKSSKS AND APPLIANCES IN BRIDd E-\V(Jllh'. 165 in Fig. 296. The gold or platinum forming the top of the cap on the root is made perfectly flat and left projecting a little at the Fig. 294. Fig. 295. Fig. 296. sides. A contoured crown of pure gold, or gold lined with platinum as a precaution against melting, is shortened sufiiciently to represent the absent coronal section of the tooth. In the side of the gold crown a slot is cut large enough to form the anchorage cavity the bur is to rest in. A shell of thin platinum of the size and shape of the anchorage cavity is then inserted in the slot and cemented with wax on the inside of the crown. The crown is Fig. 297. then invested and filled with 18-carat gold solder, which should be cut into small pieces, and be placed successively in the 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 to the cap, the pivots of which are protected with investing material (Fig. 297), and sol- dered, making a perfect joint. This is an easy method of con- structing an otherwise diflicult form of crown. Fig. 298 illustrates from the palatal side a bridge of two solid gold bicuspid dummies supported by a bar-anchorage in a solid gold crown on the roots of a molar, and a shell crown on a cuspid. 166 ARTIFICIAL CROWX- AXD BRIDGE-WORK. All-gold Hollow Dummies are recommended in a large propor- tion of eases in preference to solid ones. Tliej are formed as follows: Take a gold seamless contour crown of suitable size, with a thick g-iindiug-siirface, or one which has been reinforced with solder or gold plate and with the flux removed, and cnt away the gold forming the palatal section of the collar to the form termed self-cleansing; or shape the neck of the crown to the exact contour Fig. 298. of the portion of the giun the dummy is to rest on, and scrape a little from the surface of the model to cause pressm-e and insure closeness of fit. Melt a small quantity of solder with flux to a baU form. Fit a piece of platintmi plate, about Xo. 32 gauge, oyer the aperture, and place the ball of solder on the platinmn within the gold cap (see Fig. 299). Hold cap and platinum in a Bunsen flame, and heat slowly until the solder melts and appears Fig Fig. 300. under the edge of the cap; then instantly remove from the frame, trim the platinimi, and stone the edges. ' This gives a hermetically inclosed dummy tooth of gold, from the inten'or of which the air has been exhausted by the heat. The dummy can then l^e placed in its position on the bridge and soldered in the usual manner. Fig. 300 gives the palatal aspect of a bridge, the dummies of which were constructed in the manner described. The bicuspid dtmmiy is given a seK-cleansing form, and the molar is shaped to rest on the gum. The use of hollow gold dummies is a saving of time and ex- SPECIAL PROCESSES AND Al'I'LIANCES IS P.ItUX l i:-\V< HlK. \{^^^ Fig. 301. peiise to the operator; being of liglit weiglit, in many cases they are preferable to solid ones. For the lower jaw they can be shaped advantageously to the form shown in Fig. 301, thus overcoming the annoyance of the so-termed self- cleansing spaces. The collar section of the crown is slit on the sides A, shaped and bent inward toward the neck at the buccal as well as lingual sides, and the neck trimmed at the edges to fit the shape of the alveolar ridge. The aperture is then closed with jdati- num as shown in Fiff. 299. Fig. 302. Fig. 303. Fig. 304. Connecting Bands or Bars for Bridges, which obviate the re- moval of crowns of intervening natural teeth between the sections of a projected bridge, are formed by passing a heavy band of oval- 168 ARTIFICIAL GROWN- AND BRIDGE-WORK. shaped gold or iridio-platinum wire around the intervening teeth, close to but not touching them, and pressing slightly into the Fig. 305. Tig. 306. gum SO as not to present too pronounced an interference to the tongue. (See Figs. 302, 303, and 304.) SPECIAL PROCKSSKS AND APPLIANCES IN BUI ixi P.-WOPK. 169 Fig. 307. Fig Intervening Boots between the abutments of a projected bridge should not be extracted, but whenever practicable thej should be treated, filled, and trimmed level with the gum, as they can usually be made to afford some support for the bridge, which may rest upon them. Figs. 305 and 306 represent a case in which the root of the cuspid on the right side has been so treated and utilized. Shell Anchorage or Crown. — A shell crown or anchorage for a cuspid to support bridge-work is preferably used instead of a gold collar crown with porcelain front, where the insertion of such a form of crown involves the excision of a natural crown with a living pulp. A convenient method of construction is the following: Shape the natural crown parallel on the sides. Con- struct and adapt to the cervix, and slightly under the gum-margin of the natural crown, a gold collar wide enough to extend a little below the incisive edge. Remove a portion of the gold from the incisive labial sec- tion, and slit the palatal surface on both sides of its center, as repre- sented in Figs. 307 and 308. The part at A is bent back, and the parts at B, B beveled, bent in on the crown, and burnished close to its surface. The piece A is next brought down in position, and adapted to the crown and over the parts B, B. The collar has now assumed the form of a gold crown having an open face and seams. The seams are next united by placing, melt- ing, and flowing solder into each of them, a little at a time, by hold- ing the crown with tweezers in a Bunsen gas-flame. The seams will hold and retain solder sufiicient to join and flU them without its flowing over the adjacent parts, unless there is an excess of heat or solder. When the soldering is completed, the crown is adjusted, a line showing the exact portion of the labial aspect to be exposed marked on the gold, the crown removed, its edges trimmed to the mark, and the soldered parts smoothed with corundum-wheels and points on the engine. Another method for the construction of a shell crown prefer- ably practiced by some is: Fit a gold collar around the natural crown, and remove the gold at the labial aspect as shown at a, Fig. 309. In the vacancy between the collar and tooth at the 170 ARTIFICIAL CROWN- AND BRIDGE-WORK. palatal side, fit and biirnisli a piece of pure gold or thin platinum, which will cover the exposed surface of the tooth at that part, and fill in the space between the collar and piece of plate with wax cement, d, Fig. 309, shows the form generally of the piece of plate before it is fitted in the collar. Remove the collar, invest, and flow solder into the space between the piece of plate and collar, • Fig. 309. and remove the surplus crown; h and c show the A Seamless Shell An impression of a natural moldine, a die of fusible die in lead is made. Crown.") On the die a Fig. 310. gold of the collar extending above the finished shell crown. cliorage is formed as follows: From an crown taken in plaster, gutta-percha, or metal is formed, and from it a counter- (See chapter on "Gold Seamless Cap- crown is stamped from a seamless cap of Fig. 311. gold (Fig. 310). This crown is then fitted on the natural tooth, the labial aspect of which is exposed by the removal of the sec- tion of gold covering it in either of the forms shown in Fig. 311. 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 in- vesting material, and strengthened by flowing 20-carat solder over the surface. SPKC/AL riKX'KSSIlS AM) M'I'LIA XdlS I .\ /!/,'//>(.■ I!- n< >Uh'. IJl ¥ov cuspids this process has decided advantages in the easy formation of a perfect- fitting crown or shell for l)ridge-work. Fig. 312 shows the forms usually given shell crowns for Li- cuspids. When the gold is removed at the labio-cervical part, the croM'n should ])c additionally secured Ity a pin introduced and sol- dered at the point A. Fkj. 312. Fi.;. 313. Fig. 313 illustrates a bridge in which the lower incisors are supported by shell crowns on the cuspids. In cases where this form of crown is expected to sustain a great strain, the gold, at the cervico-labial section should be re- inforced hij the addition of a strip soldered across it and extending around on the sides. Fig. 814. Fig. 314 represents the restoration of the inferior bicuspids and molar on the right side, by a bridge with a shell crown on the cuspid and an all-gold crown on the second molar as abutments. To secure a better adhesion of the cement in the cementation of such caps, the surface of the enamel should be cleaned with pul- verized pumice wet with aromatic sulfuric acid. The tooth is then washed and dried perfectly. The cement should be thoroughly mixed to the consistence of a thick cream, the inside of the band covered Avith it, and then the surface of the tooth and the bridge brought to position. CHxiPTEK III. EXTENSION BRIDGES. This term is applied to bridges wMcli are cliiefly supported by one abutment. In relation to the anterior teeth, it consists in attaching a dummy to an artificial crown, to replace an adjoin- ing absent tooth. A bridge of this style replacing two or three of the posterior teeth is formed by using two of the teeth anterior Fig. 315. "Fio. 317. EiG. 316. Fig. 318. to it as one abutment, with 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, placed under the posterior tooth of the bridge. Figs. 315 and 316 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, the teeth forming the 172 KXTEXSloy JilUDdKS. 173 abutments were first crowned. The crowns were then adjusted in position, and an impression and articulation taken in plaster, in which the crowns were removed. From this impression a model was made of plaster and marble-dust, and an articulation in plain plaster. With the crowns in position on the model as in the mouth, the bridge was then constructed by the methods described on page 154. The part of the model oji which the saddle rested was marked, and enough of the surface of the plaster removed to cause the saddle to press tightly against the soft tissue when the bridge should be completed and inserted in the mouth. This can also be more accurately accomplished by marking the space the saddle is to occupy on the surface of the impression, and fitting thereto a disk of thin sheet lead of from No. 22 to 30 gauge as the hardness of the membranes suggests. The space occupied by the lead will cause a proportionate depression on the model when made. As the edges of the saddle should press more forcibly against the tissues than the central portion, it is well to slightly scrape the plaster at the margins. In the cementation of the bridge care should be taken that no particles of oxyphosphate re- main under the saddle. All-gold crowns which are to sustain the strain of an extension bridge should be stiffened with solder so as to possess great rigidity. If this precaution is not taken, in some cases the constant spring- ing motion of the extension bridge will gradually bend the gold of the side of the gold crown away from the surface of the natural tooth, and cause leakage by disintegration of the cement. A shell crown on a cuspid can be used as an abutment in this style of bridge, instead of excising the natural crown and mounting an artificial crown on the root for the purpose (Figs. 317, 318). Figs. 319 and 320, 321 and 322, represent small extension bridges of frequent construction, the former to repair losses in the anterior portion of the mouth, the latter to replace posterior teeth. Dr. T. Fillebrown's method of constructing a bicuspid or molar all-gold crown when the sides of the natural tooth have not, for some reason, been reduced in dimensions to that of the cervix, is to first form and fit a full-sized collar of thin pure gold, then adapt and solder over it a second and narrower collar of thin 22-carat gold plate, extending only from the occluding surface about half 174 ARTIFICIAL CROWN- AND BRIDGE-WORK. the distance to the gum-margin. The cap for occluding surface is then added in the usual manner. When the finished crown is Fig. 319. Fig. 321. Fig. 320. Fig 322. cemented in position, and while the cement is yet quite soft, a burnisher is passed around the neck of the crown, and the pure gold forming that part, as represented by A, Fig. 323, is brought close against the neck of the natural tooth. This method of form- ing a gold crown may be advantageously practiced in these cases of bridge-work. Fig. 324: shows a pin shell crown which can be made to support a porcelain front representing a cuspid or bicuspid. By forming Fig. 323. Fig. 324. Fig. 325. two grooves, respectively in the mesial and distal sides of the natural tooth, for the reception of platinum pins passing through EX TESSIO S li II ID G ES. 17^ the gTindiiig-siirfacc of tlic cap and fastened with a little solder on the outside, great security of attachment is obtained with a partial cap, and without the least exposure of gold (see Fig. 325). In a favorable case a cuspid cap may be formed on this plan to support a lateral. A third pin may be necessary at the palatal side of the cuspid. The same result can be obtained, but in a more laborious way, by first forming the grooves in the sides of the natural tooth, then making a collar of pure gold, about E"o. 33 gauge, and burnishing it well into the grooves, and removing and flowing 20-carat gold plate over the outer surface of the collar. The grinding-surface is next added. The gold is then removed from the laljial surface of the cap sufficiently to expose the natural tooth. In most cases where shell croAvns are used on the upper jaw, the gold forming the posterior side of the cap can be brought round slightly on the labial surface of the tooth without being observable 176 ARTIFICIAL CROWN- AND BRIDGE-WORK. when viewed from the front; but it must be cut short at the an- terior side and not allowed to extend beyond the line of the porce- lain front placed alongside of it. On the lower jaw the band of gold which extends across the labial aspect need only be re- moved enough to avoid exposure in speaking. Figs. 326, 327, and 328 represent an extension bridge. The anterior abutment consists of the six front teeth, which were all crowned and joined together, the pulps being preserved in the incisors. A saddle on each side forms the posterior abutments. In cases similar to this, when the dummies are extended to such an extreme distance posterior to the abutments, if antagonizing molars are present, a mere saddle is insufficient to equalize the strain, especially as absorption goes on to some extent under the saddle. An extension of not over two teeth on each side, resting on a plate or saddle extending from the cuspids back beyond the bridge teeth or dummies, is suggested instead. Fig. 329. Fig. 330. Fig. 331. Fig. 332. A Spur Support consists of a flange formed at the end of an extension bridge, affording support by resting on the palatal wall of either an incisor or a cuspid, or in the sulcus between the cusps of a bicuspid or molar, as shown in Tig. 329. Fig, 330 illustrates EXTENSION lilllDdKS. I'J'J a case with a spur resting against a cuspid. In the case repre- sented in Figs. 331 and 332 the spur rests in an indentation in an amalgam filling in the molar. This form is termed a cantilever bridge. A spur is best formed as follows: "When the dummies are mounted on the model ready for investment, adapt on that portion of the tooth where the spur is to rest a piece of very thin platinum. Place on the surface of the platinum, when adjusted, a still nar- rower piece of gold plate. Wax them in position and invest. The ends of the platinum and plate should be left extending far- ther across the tooth than will be required for the spur, to furnish a means of retaining the metal in position in the investment during soldering. The wax should only cover the portion of the spur to be soldered. In extension bridge-work, the portion which constitutes the bridge exerts on the abutments, in resisting the force of occlusion, an action like that of a lever. The ratio of the force exerted is proportioned to the length of the bridge or lever from the abut- ment or fulcrum. This principle must receive consideration in the employment of this form of bridge. A flange or spur sup- port, if attainable, should as a rule be applied. More than one tooth should not be extended from an abutment without ample alveolar support besides. When two approximal crowns support an extension bridge tooth or dummy, the force is counterbalanced by the resistance of the farthest anchorage cro^vn from the bridge, the pressure on which is in a direct line from the socket, the ap- proximal crown acting as a fulcrum, the force on which is upward in the line of the root. The occluding surfaces of the bridge teeth should be made unusually narrow from labial to palatal side,^ to offer less occluding surface to those antagonizing. 13 CHAP TEE IV. BAR BRIDGES. This style of bridge receives its name from tlie fact that the teeth or dummies forming it are supported by bars anchored in the natural teeth on either side by means of fillings. Failure to appreciate its limitations and faults of construction are re- sponsible for disappointments in its use which have militated against its more common application. In the first place, its successful employment is confined to the insertion of one, or at most two teeth. An attempt to support more than two teeth by this method will most certainly result in failure. The most glaring fault of construction is insufficient anchorage for the bars. If the anchorage tooth is alive, the bar should ex- tend in a suitably shaped cavity two-thirds or three-fourths the width of its palatal or occluding surface, Tig. 333. according as it is an incisor or a cuspid, or /i\ a bicuspid or molar, and be thoroughly se- / ;j ; cured by the filling-material. Thus an- chored, tlie bar is capable of supporting the bridge and resisting the leverage exerted on it in occlusion and mastication, which it can- not reliably do when simply anchored in a shallow filling inserted in the side of a tooth, — an incorrect method too often practiced. In a pulpless tooth the bar should be bent and inserted into the root-canal, as shown in Tig. 333. In the incisors and cuspids the anchorage cavities or slots are ■formed in the palatal portion of the teeth, extending from the ap- ■proximal surface contiguous to the space to be bridged, two-thirds to three-fourths the width of the tooth, and usually about one- 1-hird of its length from the gingival margin (Fig. 334), direct access into the cavities being afforded through the palatal wall. 178 BAR BJillXIKS. 179 The slots or cavities having been formed, a model of the case is made. Should the cavities to receive the bar be imperfectly rep- resented on the model, they should be trimmed and shaped to cor- respond to those in the mouth. The exact alignment of the porce- lain tooth in the mouth having been determined with the aid of wax, it should be adjusted on the model and secured in position by a matrix of plaster. The base of the tooth should rest firmly on the gum, to accomplish which a small portion of the plaster should be removed from underneath the tooth on the model. The bar is best constructed of platinum or iridio-platinum wire, ISTos. 14 to 16 gauge. The platinum is more easily manipulated, but affords less rigidity, which should be considered where there is a close occlusion. The wire can be ex- tended in one piece entirely across the bridge from one anchorage to the other by bending, or by remov- ing a portion of its bulk back of the porcelain tooth; or the bar can be cut and made in two sections, if the position of the an- chorage cavities so suggests. The ends of the bar should be flattened with a hammer, an- nealed, and shaped as shown at A, Fig. 334. The remainder of the section of the bar which is to rest in the cavity is best filed on the sides, so as to give it a somewhat triangular form, the broad base of which is toward the bottom of the cavity. This form favors the ready impaction of the filling-material which is to secure the bar. The porcelain tooth having been backed, the bar, whether in one piece or two sections, is attached to it with wax cement, then removed from the model and soldered. Enough gold should be added to properly contour the tooth and securely fasten the bar. Anchoring the Bar. — Gold and amalgam are the only filling- materials suited for securing bars. Amalgam is objectionable only when the position of the cavity renders it visible. Under such circumstances, however, the exposed portion can be cut away when set, and covered with gold. Fastening one end of the bar temporarily with oxyphosphate, while the other is being secured, 180 -^ ^ TIFICIA L CRO WN- A ND BRID G E- WORK. will sometimes facilitate tlie operation of anchoring with amalgam, but the best plan is to fasten the ends of the bar with gold-foil pellets and then fill flush the remainder of the cavities with amal- gam. The amount of gold used need only be sufficient to secure the bridge against the slightest motion until the amalgam sets. When the anchorage tooth is pulpless, the end of the bar which extends into the canal should be cemented first. Frequently, when bicuspids and molars containing large cavities of decay are used for anchorages, it is advantageous to first insert the anchorage fillings, and then drill out sufficiently to admit the bar, which can then be secured with additional filling-material. When gold is the filling-material used, the rubber dam, which must be thin, is first adjusted on the natural teeth, and the bridge ■then pressed to position over it. In anchoring with gold, the best way is to first fill such portions of the cavities as are inaccessible when the bars are in position, how far to proceed being determined by occasionally trying in the piece as the gold is inserted. The bridge is then pressed to place, and held firmly while the ends of the bars are secured by condensing around them a few pellets of foil, after which the gold is carefully impacted around the bar, the filling of one of the cavities being carried to completion before going on with the other. In the preparation of the cavities, their sides should be given an undercut form with strong edges. When only sufficient tooth- structure has been removed at the approximal portion to just ad- mit the bar, it is a doubtful expedient to attempt to fill the narrow seam around it with gold. In such cases, this portion of the filling-^ is better made with amalgam, which is inserted at the sides and along the floor of the cavity before the bridge is fixed in position. Then, beginning at the interior end of the cavity, gold can be in- serted and gradually condensed toward the amalgam, with which it will imite when brought in contact. Any surplus of amalgam can be removed subsequently when it has set. Amalgam placed around the bar as here described is seldom visible from the labial side, and the quantity required is insufficient to materially discolor the tooth. In Bicuspid and Molar Bar Bridges the bar should be carried well across the occluding surface, and the end bent and imbedded in the line of the sulcus toward the side opposite to that from BAR BJ{/D(JKS. \>6i which the bar enters, as shown in Fig. 335. Forming the end of the bar in this way affords the greatest security, when it is prop- erly anchored with the filling-material, by preventing any rota- tory movement, or any loosening of the bar by force applied in a forward direction. The principles involved and the Fig. 335. . method described for shaping and securing the ends of bars apply equally well to cases where one end of the bridge is supported by a bar and the other by an artificial crown, as has been previously illustrated. An Extension Bar Bridge. — In this form of bridge the artificial (dummy) tooth is supported by a bar anchored in a natural tooth at one end only. At the other end of the bridge the bar is either made in the form of a spur to rest against the adjoining natural tooth, or it is not extended beyond the dummy. In the case represented in Fig. 336, an upper cuspid, the patient, a lady, declined to have the bicuspid capped or crowned in any way for the purpose of sup- porting the cuspid. The posterior approximal side of the bicuspid at the time contained a large filling. This filling was removed, and a cavity of proper shape to receive a bar was ex- tended forward from it between the cusps to the anterior side. A suitable bar for the cavity was formed to support the cuspid in the man- ner illustrated at A and B. The angular form (C) given the bar rendered it, when anchored with the filling-material, very secure, and fully capable of supporting the cuspid. The filling-material, which was gold, occupied most of the space of the occluding surface between the cusps. The occluding tooth was trimmed off proportionately. A spur extended from the anterior side of the artificial tooth resting on the lateral incisor. The occlusion was favorable to the insertion of the bridge tooth in the form presented, and it had been comfortably and satisfac- torily worn for ten years when last seen. When examined it showed no change, except that the force of occlusion on the cuspid Fig. 336. 182 ARTIFICIAL CROWN- AND BRIDGE-WORK. had slightly bent the bar and caused the tooth to assume a deeper position in the jaw than at the time it was inserted, though this was only to the extent of the absorption of gum-tissue under the bridge. In some instances the bar of a bridge of this kind can be ex- tended across the occluding surfaces of two teeth, and additional support thus obtained. Cast Inlays or Fillings, as described on page 127, can be used in some instances to support the end of a bar. In such a case, a short piece of wire to form the bar is inserted in position in the wax in the matrix of platinum before it is removed from the cavity,, and soldered in it. The wire permits the inlay to be removed in position at the end of the bridge. The attachment of the bridge is then made to the bar or inlay. The practical application of bar bridge-work is limited. It frequently affords advantages for artificial restoration, in many cases Avhere a single tooth has been lost, not presented by other methods. Its practical success depends chiefly upon the character of its supports and the skillf ulness with which it is anchored. CHAPTEK V. PAIITIAL CAP AND PIN BltlDGE. This style of bridge is used only in case of loss of a single front tooth. Fig, 337 represents a typical case, in which a lateral incisor (crown and root) had been lost, the cuspid and central incisor, fully vitalized, and without approximal carious cavities, remain- ing in position. Fig. 337. To Make a Pin mid Plate Bridge} — 1. Take in plaster an ac- curate impression. From this obtain a plaster model of the parts. 2. Make from pure gold, rolled to the thinness of l^o. 26, standard gauge, base-plates, 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 obtained from the model, but more conveniently by 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 that will fit easily into the interspace; back with gold or platinum; adjust in position to the gold base-plates on the model, and attach with wax cement. Remove and fit in the mouth, and chill with ice-water. IText remove from the mouth, invest, and solder tooth and plates together, as shown in Fig. 338. 1 Dr. W. F. Litch, Dental Cosmos, vol. xxviii, No. 3. 188 184 ARTIFICIAL CROWN- AND BRIDGE-WORK. 4. Tor 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 respectivelv. These openings should usually be placed about as indicated in Fig. 340j at C, D. Sometimes, owing to a close occlusion or to Fig. 338. Fia. 339. Fig. 340. 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 dentin far enough to endanger the pulp. In size the openings need not be larger than will admit a platinum pin-head, in diameter corresponding to ISTo. 13, standard gauge, with a shank of ISTo. 18, standard gauge. Into each of these openings must be fitted a platinum pin of the size indicated. The head of each pin must be made thin and perfectly flat both upon its upper and under surfaces. /'.urn. I/. (A I' AM) i'i.\ HuiijiiE. 185 5. In each of the Ijase-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. 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 con- tact with the palatal surfaces of the teeth; chill the cement, re- move and invest. Next attach the pins, and also flow solder over the surface of the base-plates to stiffen them. Fig. 338 represents the appliance without the pin. A is the porcelain tooth and backing; E, the base-plates; C and F, the openings for the pins. Fig. 339 represents the appliance completed with the pins in position. Fig. 340 represents the natural teeth and interspace B, Avith openings for retaining-pins, C, D. Fig. 341 represents the appearance presented when the bridge is cemented in position. The bridge is attached by cementing in position with oxy- phosphate. When the supporting teeth have vital pulps and very sensitive dentin, the difficulty of securing reliable anchorage for each of the plates seriously militates against this method. Loosening of the bridge, especially in "close bites," is apt to occur at the most inopportune moment, demanding its immediate re-cementa- tion. Practical experience by the author in the use of this form of attachment shows that two pins in one, if not in each, of the plates are necessary. The exception is a pulpless tooth, which ad- mits of considerable lengthening of a single pin. CHAPTEE VI. EEMOVABLE AND KEPLACEABLE POKCELAIN FKONTS. In those forms of crown- and bridge-work in whicli porcelaiii fronts are used there is some liability of fracturing the fronts, either in the soldering processes connected with the construction, or subsequently, after the insertion of the piece in the mouth, by the patient in mastication. The replacing of a porcelain front after the work has been permanently fixed in position is fre- quently attended with great difficulty, and the result is often un- satisfactory or doubtful regarding its permanency. The desire to obviate such difficulties has prompted the introduction of vari- ous methods of construction in which the porcelain fronts are removed from their positions previous to the soldering processes, and afterward adjusted so as to be easily replaceable by means of duplicates in case of fracture when the work is being worn in the mouth. These methods applied to a bar bridge afford access to the cavities of anchorage. 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 foUow^s: A thick, narrow piece of 18-carat gold plate, at least ISTo. 18 standard gauge, is soldered to the tooth, and its two sides undercut with a very thin separating file (Figs. 342, 343). A very thin piece of platinum, covering the entire back of the tooth, is burnished against it, well into the undercut sides, the platinum being annealed several times during the operation. The platinum is held in a flame while a small quantity of pure gold is flowed over the outer surface and then refitted to the back of the tooth, to which it is again burnished. This operation is re- peated until the platinum and gold form a moderately light back- ing which fits perfectly. The platinum surface is then covered with investing material, and on the other side 18- or 20-earat gold plate flowed until a suitable thickness is obtained. When trimmed into proper shape and attached to the bar, this forms a 186 RKMOVAUIJ-: AND liKI'LACKABLh: I'OIKIlf.A I S FUO.\TS. Jyj substantial backing or socket (Fig. 344), in which, when the bar is anchored, the porcelain tooth can be fastened with a little oxy- phosphate cement or gutta-percha (Fig. 345).-' Fig. 342. Fio. 343. Fig. 344. Fig. 34.5. Fig. 346. Fig. 347. Any ordinary porcelain front to a bicuspid or molar dummy can be made on the removable or replaceable plan, by backing the porcelain in the usual manner with gold or platinum plate without bending the pins, adjusting the gold cap in position, at- taching the cap, and backing with wax cement, then, removing the porcelain front (Fig, 346), investing and soldering the cap and backing together. The backing must be made thick with solder, the holes in it deepened with a drill, and the pins of the porcelain front serrated and fitted therein. After the final soldering, the porcelain fronts are cemented in position with oxyphosphate. Dr. C. L. Alexander's method is to use teeth having long pins, as in Fig. 347. The facings are fitted in proper position and cemented with hard wax. The wax around the pins is then heated with the points of a hot instrument, and the facings are removed without disturbing the backings. Half-inch pieces of fine iron binding-wire are bent to form staples., their ends heated and pushed through the pin-holes from the facing side in the backings, leaving a loop on that side and projecting ends on the other, which are twisted. The wax is removed from the backings 1 Dr. F. T. Van "Woert has introduced pliers with combination points which much simplify the construction of a socket of this form and the replacement ot the porcelain front in case of fracture by the patient. Porcelain fronts or dummies of the character described with the backing baked in the porcelain of the tooth can now be purchased ready-made under the name of "Mason's Detachable Tooth." 188 ARTIFIGIAL CROWN- AND BRIDGE-WORK. and little ferrules of pure gold placed around tlie pin-holes (Fig. 348). Hard wax is next applied on the outside of the ferrules, the ends of the iron wire brought down to hold them in position, and the inside of the ferrules filled with investing material. Fig. 349 shows an invested case ready for the soldering process, which Fig. 348. Fig 340. will unite the ferrules to the backings, and at the same time join the backings to each other and properly shape them. When sol- dered and trimmed, the facings are put in place with a very thin oxyphosphate cement between fronts and backings, the pin ends Fig. 3.50. are bent down on the backing within the ferrules, and the ferrules filled with amalgam packed moderately dry. The bridge is then put aside until the amalgam has set, when it is ready for insertion. Fig. 350 shows a central crowii ready to receive the porcelain front, and a piece of bridge-work with the cuspid ferrule chambers as yet unfilled. CHAPTEE VII. GENERAL APPLICATION OF CROWN- AND BRIDGE-WOKK. The construction and general application of bridge-work, as explained in the foregoing chapters, are additionally explained and illustrated in applying them to the following typical cases: Central or Lateral Incisors, Cuspids or Bicuspids. — Figs. 351, 352 illustrate a method of replacing a superior central or lateral. The central or lateral is formed with a base of gold or platinum Fig. 35L Fig. 352. resting closely on the gum. A gold cap-crown on the first bi- cuspid is used to support it in position by means of an iridio-plati- num bar. A small spur placed on the mesial side of the bridge- tooth is suggested in such cases. Figs. 353, 354 show a case in which two centrals are sup- ported in position by bars extending from gold crowns on bicus- pids. The method of construction in these cases is: First cap the bicuspids; then fit and back the bridge-tooth or teeth and fasten in position in the mouth with hard wax. !N^ext take a plaster im- pression. Remove and make plaster and marble-dust model, show- ing teeth and crowns in position. Mark and slightly groove the line of the bar on the model. Fit the bar in position in groove, and wax ends to cap and tooth. Fasten the center of the bar and cover the teeth and caps with investing material, and solder bar or bars and cap or caps together. 189 190 ARTIFICIAL CROWN- AND BRIDGE-WORK. Figs. 355 and 356 illustrate a metliod of construction wliicli will avoid the exposure of gold, and also the presence of a bar against the membrane of the gum. A shell crown is constructed as de- scribed on page 174, Fig. 325, for the bicuspid. The crown is Fig. 353. Fig. 354. placed on the tooth, the lateral adjusted and cemented in position, an impression taken, and a model made as described in the con- struction of case illustrated by Figs. 351 and 352. On the model having the crown and lateral in position, a flat bar is formed be- FiG. 355. Fig. 356. tween the cuspid and lateral across the palatal section of the cuspid to connect and support the lateral. This bar is made by first fit- ting across the palatal side of the cuspid, a piece of thin platinum plate touching the gold crown and backing of the lateral. Over the platinum is placed a still narrower piece of gold plate (clasp- gold preferred). These are waxed at the ends to the cap and GKNKIL \L A I'l'L IC. I TION OF ( IK) WN- . 1 A'Z> BR I IX 1 K- H ■(>I{K. \(j\ lateral, and held in position in the center with investing material. "When the ends have been attached with the solder to the cro^vn and lateral, the investment material is removed from the center and the solder is then flowed across the bar. This forms a bar with a surface of platinum to rest against the tooth. Fig. 357 shows the form of bridge-work suitable for replace- ment of one or two inferior incisors. The labial section of the shell crowns which form the support for the artificial tooth should be removed only sufficient to avoid any considerable exposure of the gold in the movement of the lips. Other cases illustrating methods for single centrals and laterals, cuspids and bicuspids, are shown in Figs. 317, 319, 321, 324, 330, 334, 336, and 345. Fig. 358 explains and illustrates a method of restoring an in- cisor and supporting the adjoining loosened teeth with succes- sive cemented connecting collars of gold in cases of pyorrhea alve- FiG. 357. Fig. 358. Claris. When the natural teeth are all present, but very loose from this disease, connecting the teeth together with a succession of bands steadies each tooth in its socket and consequently permits of much more effectual treatment. For the application of such collars the teeth generally need to be slightly separated. The col- lars may be formed of a strip of pure gold plate, about !N"o. 32 to 33 gauge, by bending and fitting the strips to the forms of any two teeth in the shape shown in Fig. 359, A. This leaves but one thickness of the plate between the teeth. An additional loop can then be added as shown at B, for one adjoining tooth. All the soldering can be done quickly with the Bunsen burner without in- vesting. Centrals, Laterals, or Cuspids ComUned. — Two laterals sup- ported by two central crowns are illustrated in Figs. 360, 361. Spurs might be additionally formed on the laterals to rest on the 192 ARTIFICIAL CROWN- AND BRIDGE-WORK. cuspids. When approximal crowns, as in this case, are united to support bridge-work, a free space should be preserved at the neck between their respective collars to admit the gum septa. Fig. 360. Fig. 361 Figs. 362, 363, 364, and 365 show a bridge of the incisors sup- ported by two collar crowns on the cuspid roots. Shell crowns can also be used for this purpose, according to the preference of the operator. Figs. 366, 367, and 368 illustrate a case with shell crowns for supports. In its construction the best method of pro- cedure is to form and fit the caps or crowns to the cuspids, re- move them in plaster impression and bite, make models, and then bridge between the shell caps or crowns with the incisors. The edges of the bands of these shell caps should be beveled and burnished close to the teeth. If properly done they will resemble gold fillings. When these shell caps become loose from disintegration of the cement they should be immediately reset. It would be well if cases of this style could be removed once a year and re-cemented. Other cases of this character are illus- trated in Figs. 288 and 305. Cuspid, Bicuspids, and Molars Combined.- — Figs. 369 and 370 show bridge-work supported by cuspid and molar cap or crown. If the cuspid contains a living pulp the natural crown should be preserved, and an all-gold or shell crown should be used in preference to the form illustrated. Figs. 314 and 315 illustrate other cases. GENERAL APPLICATION OF CROWN- AND BRIDGE-WORK. 193 Fig. 362. Fig. rSHS. Fig. 364. Fig. 365. 14 194 ARTIFICIAL CROWN- AND BRIDGE-WORK. Bicuspids and Molars Combined. — Fig. 3Yl represents a bridge on the lower jaw from the first bicuspid to the second molar. The inclination of the teeth toward each other suggests the construc- tion of the bridge in the form illustrated. The molar is covered entirely with a cap, the bicuspid only on the occluding surface, Fig. 366. Fig. 367. Fig. 868. with the gold extending only half down the coronal section of the natural crown (A). A pin inserted in the cap fitting a hole ■drilled in the sulcus of the occluding surface of the bicuspid Avill secure this cap in position. This method is very suitable to a case where the crown of the bicuspid is long and the root slightly exposed. Molars under similar circumstances can be capped for bridge-work in like manner. OENEA'AL AI'PLK'ATKjN OF CROWN- AND BRWfiK-WOHh'. 195 Fig. 809. Fig. 370. Fig. 371. 196 ARTIFICIAL CROWN-. AND BRIDGE-WORK. Fig. 372 illustrates a case of bridge-work supported by cast fill- ings on an abraded bicuspid and molar. It will be noticed that tbe molar tips forward considerably. Fig. 372. "Fig. 373 represents a practical case in wliicli the upper third molar and the 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 intervening teeth.-^ Fig. 373. "Fig. 374 represents the case as prepared for the bridge. A, the inner cusp of the bicuspid cut down to allow the placing of a sufficiently thick crown-plate; B, a cylindrical undercut open- ing between the cusps for a retaining-pin ; C, the third molar, made uniform in size from neck to grinding-surface, the latter also being considerably retrenched; D, the crown-plate of a par- tial cap, made of pure gold, soldered with 20-carat gold, and so constructed as to cover every portion of the tooth except its buccal surface, the free edge passing up under the gum; E, a retaining- pin adapted to the opening B ; F, the gold cap for the molar. "Fig. 375 represents the bridge anchored in position with oxy- phosphate cement. 'Dr. W. F. Litch. GENERAL APPLICATION OF CROWN- AND IJRWaE-WORK. 197 ''In the above case it will be observed that there is a considerable space between the bicuspid and cuspid. This made it readily Fio. 374. 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. 'Tig. 376 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 fit into a slot (at D); 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. 377 shows the Ijridge anchored in position. "This case, after two years of wear, was still in perfect con- 198 ARTIFICIAL CROWN- AND BRIDGE-WORK. dition and doing good service. As it was possible to keep the gold attachments, backings, etc., out of sight, the appearance pre- sented is very natural. Fig. 376. "The absence of antagonizing teeth for the bicuspids in each of these cases was a favorable condition, as a considerable thick- ness could be given to the crown-plate without any interference with occlusion. When the conditions are not so favorable, cut- FiG. 377. ting down the inner cusp to the required extent and sinking the opening for the retaining-pin to the necessary depths are processes certainly to be, as a rule, preferred to the entire removal of the crown for the purpose of f erruling the root for the mounting of a crown of gold and porcelain, — a procedure, however, not by any means to be indiscriminately 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 ad- visable, the former may be employed as a compromise, or even GENERAL APPLICATION OF CROWN- AND BRIDGE-WORK. 199 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. 378. Fig. 379. Incisors, Cuspids, Bicuspids, and Molars combined. — Figs. 378 and 379 represent a piece of bridge-work extending from a central incisor to a molar. In such a case the best method of pro- cedure usually, and specially the one most likely to prevent misfit from warping, is, construct the front section, consisting of the central, lateral, and cuspid; next form the molar cap. Fit the molar cap and front section of the bridge in position in the mouth, remove in plaster impression and bite, and construct the bicuspid and molar dummies between the cuspid crown and molar gold cap. In a bridge of this character, if the natural cuspid is intact, a shell crown may be used. Fig. 380 gives the palatal view of a Fig. 380. piece of bridge-work consisting of a gold cap on the molar and shell cap on the crown of the cuspid, supporting a single bicuspid and a lateral incisor. Fi principle. 303 illustrates bridge-work similar in 200 ARTIFICIAL CROWN- AND BRIDGE-WORK. EXTENSIVE APPLICATIONS OF CROWN- AND BRIDGE-WORK. The following illustrations of cemented bridge-work bj Dr. H. A. Parr show extreme cases in the way of large operations in which the system has been applied. Figs. 381, 382, 383, and 38i represent a case in which the roots of the two superior centrals, a partially decayed right first molar, and a badly decayed, pulpless left first molar were all that remained of the upper natural teeth. On the two central roots were mounted collar crowns, and on the two molars all-gold cap- crowns. These four crowns, acting as abutments for the bridge denture, bore between them, proportionately on each side, the force and leverage of occlusion. The contour of the arch in the region of the cuspids was restored by a skillful and artistic placing of the artificial teeth, which are prominent and long. Tigs. 385, 386, 387, and 388 represent a case in which two large and firm superior cuspid roots, and a right pulpless molar, with a saddle on the left side, support a large bridge. In the case illustrated by Figs. 389 and 390, two superior molars and a second bicuspid on the right, and a first bicuspid and a saddle under the "dummy" representing the first molar on the left side, form the abutments. Prior to the insertion of the bridge-work, the patient had worn artificial teeth on a plate. The advisability of extensive permanently cemented bridge-work, such as is illus- trated in this and the case illustrated in Fig. 386, is questionable. The permanency of the latter probably, and most certainly that of the former, cannot be assured. The lateral force of mastication, exerted on the bridge, will Tig. 381. EXTENSIVE Al'I'LICATIONS OE CROWN- AND BRID(JE-\['(jRK. 201 Fig. 382. Fig. 383. Fig. 384. 202 ARTIFICIAL CROWN- AND BRIDGE-WORK. Fig. 385. Fig. 387. Fig. 388. EXTENSIVE APPLICATIONS OF CROWN- AND BRIDd E-WORK. 203 especially affect the side on which the saddle is used, and in time is certain to loosen and destroy the abutments. Cases such as these, where the bridge is so extensive and the abutments so few, are more properly served by inserting what are termed removable plate bridges, which have alveolar support in addition to the abut- ments. The insertion of bridge-work in cases of this character to avoid the presence of a plate can only be regarded as a temporary expedient to afford a respite from that annoyance. It is therefore an expedient not to be indorsed, as the patient in a short time will again have to resort to a plate and again experience the initiatory unpleasantness attending its insertion. In the bridge-work illustrated in Figs. 391, 392, and 393, crowns on a second bicuspid, a pulpless molar, and the roots of a cuspid and lateral constitute the abutments. Fig. 389. Fig 390 204 ARTIFICIAL GROWN- AND BRIDGE-WORK. Fig. 391. { \ r'''''M 'V- i^ \ Fig. 392. Fig. 393. EXTENSIVE APPLICATIONS OF CROWN- AND BRIDGE-WORK. 205 Fig. 394. Fig. 395. Figs. 394 and 395 illustrate an extensive case of artificial re- j)lacement by crowning and bridging operations. Fig. 394 repre- sents the case as presented for treatment. The few remaining superior and inferior natural teeth had no corresponding antago- nists, which caused the interlocking and abnormal condition in regard to occlusion shown. The superior right bicuspid, the left central, and the left cuspid were crowned, the bicuspid being short- ened and the cuspid lengthened in the operation. The intervening 206 ARTIFICIAL CROWN- AND BRIDGE-WORK. lateral root between the central and cuspid, having been treated and filled, was allowed to remain. With, the three crowns to serve as abutments the intervening spaces were bridged with artificial teeth, the extension on the left side being supported by a saddle. The spaces between the inferior cuspids and molars on both sides were bridged, the bicuspid on the left supporting the bridge, instead of the cuspid, as on the right; the left cuspid was crowned and the incisive edges of the incisors trimmed even. Fig. 395 illustrates the finished case, and shows the complete artificial restoration of the parts. Fig. 396. Figs. 396 and 397 represent a case in which crown- and bridge- work has been extensively applied. The occluding surfaces of the teeth were affected with abrasion. Gold crowns with porce- lain fronts which presented laterally the form illustrated in Fig. 396 were mounted on the incisors and cuspids, the pulps of which were preserved. The posterior teeth were crowned with all-gold KXTEysiVK .\i'i'Li(j.\'n(>.\s (>i- (:i>,<)WS- amj i'.i:U)'ii:-\vthe holes at the palatal side. After the backing is drilled grind the porcelain to fit it as perfectly as possible, place it in position and grind off the pins so they slightly protrude. If a suitable long-pin tooth is not procurable, the short pins of an ordinary tooth can be lengthened by bending a piece of platinum wire in the form of a semicircle, and soldering its ends to the ends of the pins with pure gold. The wire is then cut in the center, and the 208 hi: I'M It OF Ch'OH'X- <>i{ bhiixik-work. 209 lengthened pins trimmed as required. The pins are then riveted on the palatal side into the countersunk holes of the backing. The riveting is best done Fig. 399. IS with punch forceps having a large punch, the porcelain front being protected by a piece of lead placed against the labial as- pect (Fig. 398). The heads of the pins should then be burnished smooth with a revolv- ing burnisher. In case of the fracture of the porcelain front of a bicuspid crown or dummy, a corresponding front is selected with very long pins, and ground to fit. Holes are drilled in the gold, in proper positions, to re- ceive the pins their full length. The pins are then roughened a little with a sharp instrument, and pins and front are cemented to the gold. Should the holes extend througk the gold at the palatal side, the cement and the ends of the pins should be covered with gold foil or amalgam. If any gold is present to protect the occluding edge of the porcelain, it should be bur- nished against the surface. Dr. F. M. Shriver's method of fastening the pins in the ba;cldng of incisors and cuspids is as follows: After having fitted the porce- 16 210 ARTIFICIAL CROWN- AND BRIDGE-WORK. lain facing and shortened the pins as described, remove the porce- lain facing and with the sleeve drill, shown in place on a tooth pin in Fig. 399, countersink the end of the pin; with the cone bur — for right angle — countersink the holes on the palatine sur- face of the backing. Prepare a small amount of thin cement and spread it over the backing, after which place the porcelain facing in position, and with a pair of pliers firmly press the facing close to the backing. Warm a small piece of modelling compound, place in the cup on the riveting pliers; then set the riveting point (see Fig. 399) in the countersunk end of the pin, gently pressing the facing into the modelling compound; remove and cool com- pound with ice-water. Replace, and with a firm hand hold the compound closely to the facing, and with a gentle pressure on the riveting point and a slight lateral motion spread the pin; then burnish it down with the round point. Another method to replace a porcelain front is the following: Back the porcelain front around the pins with platinum foil, bend the pins down together on the platinum, and hammer them flat. Invest and flow a little gold plate over the pins and platinum, and file the metal down close to the porcelain. Drill a hole in a strong part of the backing on the bridge at a central point, square the hole, and fit to it a piece of square platinum wire. Attach the end of the wire to the backing of the porcelain front with an atom of wax cement, and while warm insert the wire through the hole in the backing on the bridge, and adjust the porcelain front in cor- rect position. Chill, and remove front and wire. Invest, and solder wire to backing on porcelain front with 18-carat gold solder, and then remove all metal from back of porcelain, except what is necessary to secure the end of the wire to the pins. Countersink the gold backing on the bridge sufiicient to permit the front to come in position. Slit the end of the wire, cement the porcelain front in position to the backing, and bend the ends outward into two slightly grooved places on the backing. Fill the slit in the wire with gold or amalgam, and smooth the surface.-^ Dr. R. W. Starr's method differs from the preceding, in that he uses round instead of square wire, cuts the pins of the porce- lain front off short, making corresponding depressions in the 1 Dr. W. W. Williamson's method. REPAIR OF C/iOWX- Oh' BRIDGE- IVORK. 211 backing on the bridge to receive them and prevent rotation, and solders the end of the wire to retain the front between the pins. He then cuts a screw thread on the wire, and secures it in the backing with a nut on the palatal side screwed into a depression reamed to receive it. Figs. 400, 401, 402, and 403 illustrate this method. Fig. 400. Fig. 401. Fig. 402. Fig. 403. 4 ' Dr. E. A. Bryant describes a method^ of repairing bridge-work by the aid of a set of tools, now made and sold for the purpose, which easily accomplishes the results obtained in the preceding example. Dr. Bryant's method and tools are briefly described as follows: Fig. 404. i ^ Each pin of the selected tooth-facing is to be screw-threaded with die No. 1, Fig. 404, first oiling the pin and finishing it with die i^o. 2. The pin-holes in the bridge backing are countersunk from the rear with the right-angle engine reamer 'No. 3 (see A). With the nut-driver ISTo. 4, one of the gold nuts ISTo. 5 is caught on one prong (see B), and started on one of the pins (see C), and then the other nut is likewise started. Turning one after the other, the nuts are screwed tightly on (see D), and then with engine points the projecting pins and nuts are ground flush with the backing. 1 Dental Cosmos, June, 1894, page 370. 212 ARTIFICIAL CROWN- AND BRIDGE-WORK. Bridge-work can be made with replaceable porcelain fronts which can be easily substituted in case of fracture. A description of their application will be found at page 187. If the character of the breakage is such as will not permit its re- pair in the mouth, the bridge must be removed for the purpose and then reinserted. Under such circumstances the advantages of bridge-work in a detachable form are most evident. The results following the repair of single crowns in the mouth will seldom repay the labor attending it. Removal of Cemented Crowns and Bridges. — When it becomes 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, which when exposed is severed, and the attachment of the cement broken up. The collar can also be slit and bent aside if foimd necessary. If previous to cementation the post of the crown is covered with a film or sheath of gutta-percha, as described in process of cementation on page 137, the detach- FiG. 405. ment of the post when the crown is well heated is usually easily effected. In an all-gold cap-crown on a posterior tooth a hole drilled in the 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 divided 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 instrument. A crown-cutter, an instrument made for the purpose, will facilitate this part of the operation (see Fig. 405). With care and patience 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 or crown-setter (see Fig. 262) can be placed against RKIWIR OF CROWN- OR BRIDOE-WOHK. 213 the metallic part of the crown, or the crown seized with the beaks of heated forceps, the gutta-percha thereby softened, and the crown removed. A hole or slit in a gold collar or crown is repaired easily by first placing a piece of soft wax in the hole or slit on the outside of the gold, adapting a piece of platinum foil larger than the aperture on the inside close against the gold, and fixing it to the wax. The interior of the crown is next filled with investing material, and solder flowed over the platinum and gold on the outside of the collar or crown. The crown should be heated slowly, to allow the plaster to dry out before the soldering is begun. CHAPTEK IX. THE HYGIENIC CONDITION OF THE MOUTH AS AFFECTED BY BKIDGE-WOKK. The probable future condition of a mouth in which a piece 01 bridge-work is permanently fixed is a matter of the deepest interest to both patient and operator. There is no valid reason why an artificial structure in the mouth should be more hurtful than that which is natural, provided that correct conditions are observed in its construction and proper measures are taken for their maintenance. The natural teeth demand care on the part of their owners, and all forms of artificial dentures require at- tention to secure their cleanliness and thus preserve the health of the adjacent tissues. What will result from the wearing of a permanently fixed bridge is almost wholly dependent, in the first place, on the proper application of principles and correct formation in every detail of construction of both crowns and bridge-work; and in the second place, upon the maintenance of cleanliness. E^eglect of a single requirement will so far detract from the usefulness of the work, and may influence the final result disastrously. Firm, properly selected abutments will not redeem incorrect conception or faulty construction; neither will the best construc- tion remedy that which is wrong in principle or application. Self- cleansing spaces, if properly formed, have exactly the contrary effect from what is intended, by becoming receptacles for particles of food debris, instead of preventing their accumulation. Inaccessible spaces or interstices, which are always apt to cause uncleanliness, should be avoided. Continuity of structure of the several parts is also essential to fully insure perfect hygienic condi- tions. The health of a mouth containing a piece of bridge-work con- structed under these precautions can be readily maintained. For this purpose a suitably formed brush and a dentifrice are neces- 214 77//'; lIVdlKNIC CONDITION OF THE MOUTH. 0\^ sary. Floss silk can be passed through apertures around the necka of crowns, in places out of reach of the brush, and drawn along the gum under the bridge by the aid of a slightly curved blunt- pointed needle, to remove accumulations of debris otherwise in- accessible. A solution of a detergent and disinfectant mouth lotion in water, injected with a dental syringe, can be used ad- vantageously to wash out such places and maintain a healthy con- dition of the gums. In addition to these measures, the crown and bridge should be thoroughly cleansed by the dentist at regular intervals. So cared for, a permanently fixed bridge will not militate against the absolute wholesomeness of the mouth; but it can hardly be expected that the insertion of bridge-work will insure a state of the mouth which for cleanliness will be superior to the presence of the natural teeth. ISTeglect on the part of the patient to perform such duties as are necessary to preserve the natural teeth in a healthy state will have about the same effect on an artificial denture. The attention required to be given to bridge-work is not greater than is commensurate with the advantages which it confers on the wearer. CHAPTER X. EEMOVABLE AND DETACHABLE BKIDGE-WOEK. The evident advantages of bridge-work early stimulated the inventive genius of dental mechanists to improve the methods and forms of its construction and to extend its application. With these objects in view, methods have been introduced by whicll bridges are so constructed as to be removable by the patient or de- tachable by the dentist. The construction of bridge-work in either of these forms in some cases overcomes the chief objections argued against the sys- tem. 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. Some forms of small bridges cannot be made removable. To so construct many others would interfere with their practicability. Besides, in a large proportion of cases where properly constructed bridge-work is applied, the removable feature would be of no benefit, so far as regards the health of the abutments or of the ad- joining teeth; neither would it be of any great advantage respect- ing cleanliness. These reasons, together with the fact that re- movable bridge-work is most intricate and laborious in construc- tion, combine to restrict its use in practice. Much that is here stated concerning removable bridge-work might be applied to the detachable form. The necessity for using the latter in preference to the former is limited to a very small sphere, owing to the fact being demonstrated that gutta-percha, alone or combined with oxyphosphate, can be used practically as a cement in most cases, thus permitting the removal of a bridge without much difficulty. In the construction of removable bridge-work a prime requisite is that the posts and collars, or other form of attachment used, shall be so formed that the piece shall move evenly on or off the supporting roots or crowns in adjustment and removal. To secure this, the post-cavities and the gold crowns should be so shaped that the lines of the cavities and of the sides of the gold 216 REMOVABLE INCISOR OR CUSPID CROWN. 217 ■crowns shall be as nearly as possible parallel to one another. To facilitate this, a post of wood or metal may be first accurately but loosely inserted in any root-canal intended to receive a post, and left protruding a quarter of an inch, and an impression taken. On the model made from this impression the post will be found placed as in the mouth. The position and shape of the natural teeth or roots can be thus studied, and their plaster forms trimmed as a guide. Gutta-percha or impression compound, fitted to the mode^i and removed with the posts in position in it, can then be used to guide the operator and gauge the preparation of teeth or roots in the mouth. Posts, or the tubes inclosing them, should be placed as nearly as possible in the lines of the root-canals to avoid weakening the side or sides of the root. When a molar leans forward, the removal of a portion of tha anterior approximal side usually restores its perpendicularity suf- ficiently, as does the cutting away of the posterior side of a bicuspid which inclines backward. The methods and forms of attachments most commonly used in the different styles of removable bridge dentures are very simi- lar. A preliminary description of these and of their constructive details is therefore first in order. REMOVABLE INCISOR OR CUSPID CROWN. A removable gold crown with a porcelain front is frequently used in connection with removable bridge-work where incisors or cuspids form abutments. The cap and tube crown is the style (Fig. 406) prefer- ably applied. It consists of a cap for the €nd of the root with a tube attached ex- tending up the root-canal, and on the cap the crown with, a post fitted tightly to the tube is adjusted. To the crown so formed (Fig. 407) the bridge is joined in the usual manner. The end of the post can be formed with a slit which will permit this portion to be slightly expanded, making what is termed a spring-post. The con- structive details of this crovm are as fol- lows : The root is first prepared and capped the same as for a collar crown. The collar can be formed of gold Fig. 406. Fig. 407. 218 ARTIFICIAL CROWN- AND BRIDGE-WORK. and the cap section of platinum, ISTo. 32 gauge (A, Fig. 408). A substantial piece of gold and platinum wire, from IsTo. 16 to ISTo. 18 gauge (the number being regulated by the size of the root), is slit for about one-eighth of an inch to form a spring-post. This is easily done by placing the wire in a vise and steadily cutting it downward from one end through the center to the required depth with a saw-edged strip of very thin steel (Fig. 409). This takes only a few minutes, and is preferable to the method some- times adopted of partially joining two pieces of half-round wire. The wire is then tapped together at the slit, burnished smooth, and rounded just at the end (B, Fig. 408). The tube for this post is formed by once encircling the post with a piece of iridiot platinum plate, JSTo. 34 gauge, the edge of which is beveled and cut to meet the plate even and close (C). The post is then Pig. 408. Fig. 409. Fig. 410. I D W B withdrawn, and the seam is touched along its length with the smallest possible quantity of borax. The proper way to use borax in fine work is to grind it, mixed with water, on a slab, to a cream- like consistence, and apply on the point of a camel's-hair brush. A very small piece of pure gold is placed in the seam, and the tube is held in a Bunsen flame. When a sufiicient degree of heat is reached, the gold will flow along the seam and form a joint without obstructing the inside passage for the post. The post is then in- serted, and the tube trimmed (D), and gauged in a gauge-plate. With a drill just the size of the tube the root-canal is enlarged so that the tube will fit tightly (Fig. 410). This plan prevents weak- ening of the root by too great enlargement of the canal. A hole the size of the tube is made through the cap, and cap and tube are then adjusted, waxed together, and, the post being withdrawn, REMOVABLE LWISOIl OR (JUSR/D CROWN. 219 they are removed, invested, with the investing material inserted in the tube, and soldered. The second or outer cap is then con- structed for the root-cap, of a piece of platinum about ISTo. 34 gauge. It is perforated in the center, and the post fitted in proper position. At the palatal and approximal sides, if desirable, the l^latinum can be slit and bent over the edge of the root-cap to form, an inner partial band or flange, or a half band can be formed of a piece of plate, the open space at the labial side being filled with the porcelain tooth. The outer cap and the post, having been cemented with wax, are removed and soldered together. As the point of the post may have to be filed, it is well to place it so that the line of the slit shall cross the tooth from mesial to distal side. On this outer cap the porcelain front is fitted and soldered. The end of the tube is closed with a little gutta-percha, and the root- cap cemented on the root with oxyphosphate and the crown placed on it, wliich helps to bring the root-cap to its place and insures the intended position of the crown. When necessary, the split post can be tightened in the tube by slightly springing it open. Fig. 407 represents the finished crown. The incisive edge of the porcelain does not necessarily require to be protected with metal as in fixed bridge-work. A square tapering post, either solid or split in some cases, is preferred to the form above descrilied, especially in a root of a cuspid. When a split post is used, the points should be soldered together. The lower section of the post can then be alone expanded and tightened in the tube (Tig. 411). To receive the tube and post, the canal should be carefully deeply opened and then shaped mth a reamer, such as is illustrated at Tig. 72. Fig. 412 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, and a post attached fitting the root-canal. A j^orcelain cross-pin tooth, the pins of which are set w^ell apart, is then ground and adjusted in position, cemented with wax to the cap, and both removed. Enough plas- FiG. 411. Fig. 412. 220 ARTIFICIAL CROWN- AND BRIDGE-WORK. ter to form a matrix is placed on the labial aspect of the porcelain and collar to hold them in relative position when the wax is re- moved. A flat post is then formed on the root-cap, extending from the palatal edge forward between the pins of the tooth, the porce- lain of which, between the pins, should be 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 gold plate ISTo. 18 gauge, and the spring of clasp or spring gold J^o. 26. The post is soldered to the cap from the opposite side to the spring by investing with- out the tooth. The tooth is then lined with very thin platinum, and with the aid of the matrix is adjusted in position 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, with its inner edge meeting the backing of the tooth. The platinum plate is then cemented with wax to the backing on the tooth, removed with it from the cap and post, and invested, the slot for the post being carefully filled with the investing material. Twenty-carat gold solder is then flowed over the plate and backing so as to con- solidate the parts in one piece. This crown when finished will fit on to the cap and post, the spring of which can be bent to securely retain it. The line of the post on the cap as it fits in the slot in the crown should be such as will favor the insertion and removal of the bridge. In the form shown in Fig. 413, which is a sectional view, a square or round iridio-platinum- wire is used as a post ^r^ on the cap instead of the form above described. p \ The post having been soldered to the cap, a thin M|"V j piece of platinum is first perforated and fitted over B the top of the cap, next a tube of platinum over the ^,__-_^ post and between the pins of the porcelain. The MjT]\ porcelain front is then lined with platinum foil, and \ i_ / / cemented with wax to the tube and the platinum at the base, and removed and soldered together. AVhere one end of a bridge is securely attached to a first molar having a long crown, the form of crown here described is ample support for the other end on a cuspid. JIKMOVABLK BICUSPID AND MOLAR ATTACHMENTS. 221 REMOVABLE BICUSPID AND MOLAR ATTACHMENTS. Biciisi)ids and molars, especially the latter, in all cases where possible, are the teeth selected and most depended on to support all forms of removable bridge-work. Removable Partial Cap and Collar. — This is a form of attach- ment made to fit over a natural tooth, or more frequently a gold crown. The sides of the natural tooth have to be first trimmed as nearly as possible straight or parallel to the sides of any other supporting crown or line of attachment. If the tooth is to be first capped, a straight-sided gold crown is made and fitted. A fusible-metai die of the gold crown is then made; or, better still, the gold crown is removed, a strip of damp paper wound around it, and fusible metal melted and poured in crown and paper tube. This forms a die of Fig. 414. Fig. 415. Fig. 416. the crown, with a shank as seen in Kg. 414. When the natural tooth is not crowned with gold, a die of the tooth is made in a man- ner similar to that described on page 96, and in chapter on "Molds and Dies." The crown is then encircled with a strip of pure gold about JSTo. 30 gauge, one part of which will extend above the rest in the form shown in Fig. 415. The sections of the gold at A, A are to reach from the edge of the neck of the crown to or slightly above the occluding sur- face. The gold is fitted evenly, but not tightly, around the crown, the ends being placed at the side opposite to that where the collar will be joined to the bridge if the space permits. The collar is then removed and the ends soldered together (Fig. 416). The collar is readjusted on the crown, and the part at B, Figs. 416 and 418, bent down over the occluding surface, so that it nearly meets the collar section A. On the outside of the collar a slightly nar- rower strip of gold clasp plate, ISTo. 30 (Fig. 417), is next adjusted 222 ARTIFICIAL CROWN- AND BRIDGE-WORK. ill the position shown at the lines C, Fig, 41Y, then removed and the seam, which had best be located at the point C, Figs. 417 and 418, soldered together. It is readjusted on the gold collar, re- moved with it, and soldered to it. The collar can be invested for this purpose, but the work is more easily done by holding the col- lar in a Bunsen flame and placing small pieces of solder in posi- tion in the seam. Only enough solder should be used to unite the parts, any surplus being carefully avoided. Painting the inner surface of the collar with whiting will prevent the solder flowing there. The collar section of the removable cap is then trimmed smooth. The cap section at B can be adjusted and soldered to the collar now, or preferably after the cap has been united to the bridge, and its relative position on the gold crown accurately determined. Fig. 419 shows the gold crown and the finished removable par- tial gold cap over it. Fig. 417. Fig. 418. Fig. 419. Fig. 420. The gold crown is freed from the fusible metal by dropping it with the die into a ladle containing a quantity of melted fusible metal. The portion within the crown will melt in with that in the ladle and leave the crown, which should then be removed and immersed in nitric acid to remove any traces of the fusible metal still adhering to the gold. Flanged Collar Attachment. — Fig. 420 shows another form of removable partial cap. In this the entire edge of the collar is bent over on the occluding surface of the crown, and thereby supported in position. In the construction the edge of the pure gold collar should be shaped to form the flange. This form of collar may also be made entirely of clasp gold, No. 28 gauge for molars, and of I^o. 29 to 30 gauge for bicuspids. The process is: An accurately fitting collar is first made. The REMOVABLE BICUSPID AXIJ MOLAJi ATTACIIMKXTS. 223 collar is then, by tapping with a small horn or copper hammer, aided by frequent annealings, shaped on the gold crown or die of the tooth. The flange section can be slightly thinned with a small corundum- wheel, and then or subsequently brought to position over the gold crown, or the tooth, and stiffened with solder. When the collar is shaped over the gold crown, the crown should be first filled with fusible metal as previously de- scribed. Spur Collar Support. — Fig. 421 illustrates a form in which a straight-sided removable collar is maintained in position by a lug or spur on the side of a gold crown. Fig. 421. Fig. 422. Fig. 424. Removable Partial Cap and Clasp Attachment. — In this form a partial cap in combination with an elastic gold clasp, encircling only a portion of the crown, is used instead of a collar. Its ap- plication is principally confined to a cuspid or bicuspid tooth or an artificial crown. The attachment is best constructed on a metallic die, either of the natural tooth or of the artificial crown mounted on a model. In the case of a cuspid a piece of pure gold, ITo. 31 gauge, is adapted to the palatal surface and partly over on the approximal side, in the form shown at A, Fig. 422. In some cases it may be extended to the incisive edge. A gold clasp of at least 'No. 24 gauge is fitted over the gold partial cap in the position shown in Fig. 423, the cap being beveled to an imperceptible edge on the sides at the points where the clasp passes forward, to assure perfect adaptation. Cap and clasp are next cemented with wax, then re- moved and joined at the approximal sides with a very small quan- tity of solder. The attachment is then ready to be connected to the bridge denture, which should be done by soldering the clasp portion only at the point B, Fig. 423. This method allows the 224 ARTIFICIAL CROWN- AND BRIDGE-WORK. soft gold of the cap portion to be again adapted to suit any posi- tion the clasp may assume in the final adjustment of the denture in the mouth. The bridge and clasp should then be invested again, and solder flowed over and between the cap and clasp. A Bicuspid or Molar Partial Cap and Clasp Attachment. — Fig. 424 illustrates the form the attachment just described usually assumes in cases of bicuspids and molars. The dotted line marks the boundary of the partial pure gold cap. The construction fol- lows similar lines to those laid down in the case of a cuspid. If preferable, the cap section can be burnished down against the crown; and if necessary, it can be slit, and solder can be flowed over it at the final adjustment of the bridge. This form of at- tachment is especially useful in cases where a natural tooth tips out of line so as to render it difficult to entirely encircle it with a continuous band. Pure gold has been given the preference to thin platinum in the construction of these partial caps, for the reason that the form and the position of the former are less liable to be altered in soldering, an advantage which is relatively more important than the non-fusible quality of the platinum. The forms of attachments described for removable bridge- work are those most generally applied in practice. The methods for their construction, which as given are the results of practical experience, may in some respects differ from those followed by others. In application, as will be shown, they enable the operator to avoid difficulties often encountered in obtaining a proper adjust- ment of removable bridges on the abutments and alveolar border. Special forms of attachments not in general use will be described in the succeeding chapters, in their application to practical cases. Their use in combination with the forms already explained may at times prove advantageous. Connecting Bars. — Connections between the different sections of a removable bridge are formed in the following manner; An impression of the case or of the part to be spanned is taken in plaster, and a cast made by pouring into it fusible metal which melts at a point less than or not over two hundred degrees (see chapter on "Molds and Dies"). The cast must correctly repre- sent the lingual or palatal surfaces of the teeth. Upon this cast a strip of pure gold, iSTo. 30 gauge, about one-quarter of an inch REMOVABLE BfC'I'SI'/D AND MOLAR ATTACHMENTS. 225 in width and of the proper length for the required connecting bar, is burnished over the palatal or lingual surface of the teeth intervening between sections of the bridge or attachment to be connected. Wax is placed on the surface of the gold, and the gold is removed and invested. The wax is next removed, and a piece, or pieces, of gold clasp plate, a trifle narrower than the strip of pure gold, is bent and shaped to fit over its surface. Twentj-carat solder is then flowed over the gold in quantity suf- ficient to join the parts, level the surface, and make a rigid bar capable of resisting such force in use as would tend to destroy its shape in the slightest degree. When the bar is formed on the metallic cast it can be transferred to the plaster model, and then, or in the subsequent construction of the work, connected to the attachments; or the bar can be adjusted in the mouth, cemented Fia. 425. with wax or ligatured on the teeth, the attachments placed in posi- tion, and the bar and attachments removed in their relative posi- tions in a plaster impression. On the model made from this impression they will be found the same as in the mouth. The construction of the bridge can then be continued. Fig. 425 rep- resents a bar of this character to span the lower front teeth and connect attachments on the cuspid and bicuspid. For the Upper Front Teeth. — Where a bar narrower than the one described is required, the strip of pure gold should be cut pro- portionately, and pieces of half-round iridio-platinum or gold clasp wire used to form and stiffen the bar, instead of gold clasp plate. Iridio-platinum wire may be used without the pure gold base, but in such a case the sections of the wire are best soldered with either pure gold or 22-carat plate. Methods for connecting sections of 16 226 ARTIFICIAL CROWN- AND BRIDGE-WORK. a bridge are illustrated in Figs. 303, 351, 353, 430, 434, 447, 482, 590, and 594. Construction of Benwvahle Bridge-Worh. — In removable, as well as other styles of bridge-work, the method of procedure i& governed entirely by the conditions presented in each case. Therefore directions given regarding bridge-work embracing cer- tain teeth and attachments in one instance may vary considerably from what is required for the same tooth in another; consequently the process of construction can only be outlined in somewhat gen- eral terms. Fig. 426. A case frequently presented, involving the loss of a portion of the lower teeth, as shown in Fig. 426, will be taken to illustrate the method generally adopted for the construction of removable bridge-work. The molar is shaped to receive a gold crown. The anterior approximal side is trimmed parallel with the line of the posterior side of the cuspid. Removing a little of the enamel on the distal side of the cuspid will assist the operation and straighten that part of the tooth. A straight-sided gold crown is made for the molar, A bite is first taken in wax for articulating model and then a plaster impression, which will remove the gold molar crown in position, and a cast is made as follows : The form of the cuspid is first filled with fusible metal, and the remainder of the im- pression with pure plaster, as described in chapter on "Molds and Dies.*' A die is then made of the gold crown and a removable cap for the gold crown on this die, and a gold partial cap and clasp attach- ment are made on the metallic form of the cuspid. Dummies are then fitted and soldered together, placed in position, and joined REMOVABLE BKJUSI'ID AND MOLAR ATTACHMENTS. 227 to the attachments with wax cement. The bridge is then removed from the model, invested, and soldered together. In the removal of this style of work from the mouth or from a model, should the wax not hold the parts reliably together, plates should be placed over them, so that when removed they can be accurately readjusted in the plaster. Connection with the attachment is only to be made at the collar section. The gold crown and fusible metal are then separated from the model and the fusible metal removed from the crown in the manner described on page 222. The molar crown and the bridge are then fitted to the mouth. The crown is next cemented on the molar and the bridge im- mediately adjusted over it, pressed into position, and allowed to remain until the cement has set. The partial cap section of the attachments is burnished down on the bicuspid and the gold crown on the molar, while the bridge is kept firmly pressed against the gums. The bridge is then removed, invested, and the partial cap sections made rigid by flowing gold solder over them. The final trimming, finishing, and polishing of the bridge are then per- formed, and it is ready for insertion. The procedure in the case described can be varied by making the entire model of fusible metal, or by placing a little wax in the interior of the grinding-surface of the gold crown, making a plaster model, removing the gold crown and filling it with fusible metal, making the attachment and replacing the gold crown on the model. The cuspid attachment can be formed on a fusible metal cast of the tooth. The methods of construction as above given may be still further varied by first forming the gold crown and attachments to it and the cuspid, fitting them in position in the mouth, taking a plaster impression which will remove them in position, and then making a model of plaster and calcined marble-dust. On this the dum- mies can be fitted and soldered to the attachments. The gold crown is to be removed from the model after the position of the attachment on it is secured by the investing material, and the cavity in the investment is then to be filled with more investment material. Removable bridge-work is best constructed with the bases of the dummy teeth pressing firmly on the tissue of the gum. If the collar of the molar attachment should prove difficult to remove 228 ARTIFICIAL CROWN- AND BRIDGE-WORK. when first inserted, it should be slit at the posterior section, slightly expanded, and reunited with solder, when the cap sections of the attachments are stiffened in the final process of soldering. A small piece of gold plate can be inserted in the aperture of the collar to aid the gold to unite the ends. In Fig. 427 are illustrated the two forms of removable bridge- work that could be constructed for the same case. In the one a clasp attachment is placed on the natural cuspid, in the other the natural crown is excised and a removable cuspid crown con- FiG. 427. structed. In the construction of either style, a gold crown is made for the molar, with a removable gold partial cap and collar attachment. A removable partial cap and clasp attachment is made for the cuspid, or, if the natural crown is excised, a re- movable cuspid crown, and the cap and tube section cemented in position on the root. The crown or crowns and attachments are adjusted in position in the mouth. If the cuspid attachment is used, and it seems liable to become misplaced, it can be liga- tured to the natural crown. An impression and bite are then taken in plaster, and when removed from the mouth the croAvns and attachments are to be replaced in position in the impression, and a model of plaster and calcined marble-dust made, and also an articulating model in plaster. The lateral and bicuspid and molar dummy teeth are next fitted in proper position on the model. A piece of pure gold is adapted against the lateral, and burnished over the palato-approximal side of the central to form the flange. The case is then invested, the gold crown slipped REMOVABLE BlfUSPW AND MOLAR ATTACHMENTS. 229 out of the attachment, the place it occupied is filled with ad- ditional investing material, and the parts are all soldered to- gether. The construction can he varied by first making the bridge from the molar to the cuspid, and then adding the lateral and flange. When finished, a suitable quantity of cement is placed in the gold crown, the crown is fitted on the molar, the bridge adjusted in position, and the teeth occluded and so allowed to remain until the cement sets. The denture illustrated in Fig. 428, a case of Dr. A. S. Rich- mond's, was made to restore a loss of teeth which is frequently Fig. 428. met with, but one not suitable for the insertion of cemented bridge-work. The application of a removable denture combin- ing bridge- and plate-work is a method possessing some advantages over those ordinarily practiced. In brief, the constructive de- tails are: A connecting bar is formed as described on page 224. In the case in hand, when the pure gold to form the connecting bar is adapted to the cast, it is extended around and over the cuspid and bicuspid. Gold clasps are then adapted over the pure gold on these teeth, and attached with solder. The bar and clasp at- tachments are inserted in the mouth, and an impression taken in plaster. Two pieces of sheet lead about No. 26 gauge are placed on the surface of the impression where the saddles are to rest, for the purpose of causing an equal displacement on the plaster model and thus securing an even pressure for the saddles on the alveolar ridge. (See page 173.) A model is next made with the attachments and bar on it in position. Metal casts are also made of the parts at A, A, Fig. 429, and two gold plates struck up. The teeth are then arranged in position, the bicuspids resting on the gums and the molars on the two plates or saddles, and thei denture completed as shown in the illustration. 230 ARTIFICIAL CROWN- AND BRIDGE-WORK. Removable bridge-work offers peculiar advantages for artificial replacement of lower incisors in cases similar to that illustrated in Fig. 430. A portion of the contour of the approximal sides of tbe right cuspid is removed. Shell caps for the right and left cuspids are then formed of crown gold, reaching nearly to the margin Fig. 429. of the gum. The caps are encircled with a narrow strip of stiff gold plate or clasp metal, about JSTo. 35 gauge, which is soldered to the caps as described on page 224 in the construction of molar Fig. 430. partial caps, or are stiffened by flowing a film of coin gold or solder over their surface. The caps are next adjusted in the mouth, and an impression and bite taken in plaster and the caps removed in it. A model of half each plaster and marble-dust and an articula- tion in plaster are then made. Porcelain incisor teeth with straight pins are fitted in position, backed, and a broad bar ex- tending from the lingual-approximal side of the gold cap on the REMOVABLE BWUSPID AND MOLAR ATTACHMENTS. 231 left cuspid around to the mesial side of the lateral is formed of a strip of pure gold, adapted to the parts, overlaid, and soldered to a slightlj narrower strip of gold clasp plate. The different portions are then cemented together with wax, invested on the model, and properly united with solder. When finished and inserted in the mouth, it constitutes a denture that can be worn without inconvenience by the patient, and removed daily and cleansed, which last especially is a great advantage, as in a case like this the teeth replaced have usually been lost by pyorrhea alveolaris and those remaining are affected by the same trouble. Fig. 431. The natural teeth, if loose, are in a measure steadied and sup- ported by the appliance. In some cases, especially if the teeth tip, one or both of the attachments on the cuspids can be made of thick clasp metal in the form of a clasp attachment, as de- scribed on page 224. In the case represented in Tig. 431, gold crowns with remov- able partial cap and collar attachments are made for the molar and bicuspid, and removable crowns with flanges of the metal on the palatal sides for the centrals and cuspid. The right central is capped and the crown fitted over it without a post, as the posts in the other two crowns afford ample security. After the crowns are made, the root-caps are cemented on each root. The central crowns are cemented together with wax, ad- justed in position, covered with a small quantity of investing ma- 232 ARTIFICIAL CROWN- AND BRIDGE-WORK. terial, removed, more investing material added, and the crovi^ns soldered together. The centrals and the cuspid are then adjusted in the mouth, a lateral is backed, fitted, and waxed between them in position, Fig. 432. the whole removed in investing material, and the process of in- \'esting and soldering proceeded with to join the parts as before desc^ribed. This bridge of four teeth is fitted to the mouth, and Fig. 433. the points of the posts trimmed on the side and in the direction which will best favor their entrance into the tubes in each root, so that the bridge will readily slip into position. The dummy bicuspids and molar on the right side between the cuspid and molar are then added by first taking an impression and bite of that REMOVABLE BICUSPID AND MOLAR ATTACHMENTS. 233 section, and then proceeding with the construction as described in previous cases. The section of the bridge with the extension on the left side is next added in a similar manner by taking an im- pression of the part while the portion of the bridge already con- structed is in position, removing bridge and impression together as described on page 228, and making a model. A piece of pure gold is shaped to the model by alternately burnishing and an- nealing, to form a base for the molar. The one molar will exert as much leverage on the abutment of the bridge in mastication as can f^afely be borne. Fig. 432 shows the bridge completed, and Fig. 433 the piece in position. CIIAPTEK XI. KEMOVABLE PLATE BEIDGE-WORK. I]sr this style of work a plate is used to span the space and sup- port the artificial teeth between the abutments. Attachments similar to those used in connection with removable bridge-work are also applicable to removable plate bridges. Removable plate bridge-work is really plate-work secured in position by removable bridge-work attachments, and is intended to combine in a denture the advantages of both systems. In the construction of removable plate bridge-work, removable crowns, caps, or attachments are made for the supporting teeth in the same manner as for remov- able bridge-work, though clasp attachments may be somewhat more freely used. An impression of the part is taken, from which a plaster model is made. On the model an outline of the size of the required plate is marked and the edge of the space scraped sufficiently to in- sure a slight pressure for its margins. A metallic die and counter- die are cast, and a gold plate of the proper size swaged. The at- tachments are adjusted in the mouth and the plate fitted in posi- tion between the attachments, and then the plate is removed. A plaster impression is next taken, and the attachments removed in position in the impression. The gold plate is turned upside down and placed on the surface of the plaster impression between the attachments, an atom of sticky wax being applied at a point or two if necessary to retain it in position. A model is run in the impression, composed of marble-dust, sand, or finely shredded as- bestos, and plaster, of each one part. When the plaster impression is removed from the model, the plate will be found imbedded in place between the attachments. The attachments are then se- curely soldered to the plate. If necessary, before soldering, a little more investing material may be added to protect the attach- ments. A plate made after this method, when fitted "with the at- tachments in the mouth, will press on the membranes of the 234 REMOVABLE I'LATE JiJUD >l! K. 251 Fig. 4t;."). The lialf-ring is then fitted to tlie tooth, attaclied with wax, and removed with the tooth out of tlie phister matrix from the root- cap, invested, and securely soldered on the inside to the Ijacking of the tooth. The tooth and lialf-ring are then adjusted to the root-cap, over the post of which the ring must slide easily (Fig. 465). To this ring the bridge is soldered the same as to a crown. When tlie 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. 404) can be protected by a metallic filling. This form of attachment permits the bridge to be easily removed by affording access to the cement around the pin. The bar ends of the bridge are anch- ored in the crowns with gold or amalgam fillings, Avhich likewise are not difficult to remove. The anchorage cavity for a bar in a gold molar crown for use over a tooth Avitli a living pvilp is best made by cutting out the gold to the form of the slot required, and inserting in its place a piece of platinum of the shape of the walls of the anchorage cavity. The crown is then filled with investing ma- terial, and the metal forming the anchorage cavity soldered to the crown at the edo'es of the cavity. DR. R. W. STARR'S METHODS. Dr. E. Walter Starr gives the following descriptions of his methods in detachable bridge- work: "The case of Mr, W. presented difficulties of an unusual char- acter, as may be seen by inspecting the illustration (Fig. 466), which renders detailed description unnecessary. "^Tt will be observed that the molars and the left second bicuspid overhang to a degree that would make the taking of an accurate impression by ordinarj^ methods well-nigh impossible. After a careful study of the case, it was decided that two separate pieces of detachable bridge-work should be attempted, and, as an essen- tial preliminary step, the overhanging sides of the molars and bicuspids were ground with engine corundum-wheels and points 252 ARTIFICIAL CROWN- AND BRIDGE-WORK. Fig. 466. Fig. 467. DETACIIABLK A\D JiEMOVABLK BRIDGE-WORK. 253 until tliose sides were made much less inclined, when plaster im- pressions were taken, first of one half, and then of the other half, of the jaw. Gold cap-crowns were closely fitted over the molars, left second bicuspid, right first bicuspid, and cuspid stump. Gold crowns were made to telescope over all the caps, which were then, by means of oxyphosphate cement, fixed firmly on the teeth. Suitable plate teeth were selected, fitted, backed, and hard-waxed in place between the telescoping crowns. After hardening the Fig 408. wax with cold water from a tooth-syringe, the pieces were care- fully 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. 467, which also shows the capped teeth and stumps. The figure likewise shows the results of the novel method employed in crowning the incisors. Gold collars were fitted tight on the necks of the incisor stumps, and the porce- lain 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 col- lars, as shown completed in Figs. 467 and 468. 254 ARTIFICIAL CROWN- AND BRIDGE-WORK. "Fig. 468 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 only the spaces between the flat tops of the caps of the 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 upper vulcanite denture was made to replace the old one, which, by improper occlusion, had thrown the full force of mastication on the anterior teeth of the lower jaw, and produced the destructive action that resulted in the deplorable loss of tooth- substance shown in Fig. 466." ^ The next case also presented unusual difficulties. "The for- ward 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 made parallel, or rather slightly tapering to form a truncated cone, with the neck as a base. The molar was alive and sound, but the crown was gone from the pulpless cuspid, which I suitably shaped by means of my root-trimmers (Fig. 469). "An impression was then taken, the cast from which is illus- trated by Fig. 470. A seamless gold- collar was, by 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 gingival margin; a cap piece of gold plate soldered to the top edge of the collar, and a hole drilled through the center of the completed cap (A). 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; but first there was fitted to the cap a telescoping seamless collar, on which was soldered a gold plate, with cusps, to form a molar crown as shown. The molar was then thoroughly dried, slightly painted with Agate cement, and the cap, A, driven hard down with a flat pine stick held upon it and struck with a mallet; the ' Denial Cosmos, vol. xxviii, No. 1, page 17. DETACH A BLK AND REMOVABLE BRIDGE-WORK. 255 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 which was given a roof -shape, as seen above the root in Fig. 470. 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, beside which, B, its form is seen, and to which it was subsequently soldered, after suitable investment to keep the parts in proper place. The root-canal had been previously prepared to receive the tube, which, with its roofed caj), 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 position 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 hoUowness, it looked like the 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. The truss thus formed received an appropriate finish by the rounding 256 ARTIFICIAL CROWN- AND BRIDGE-WORK. and smootliing of its basal borders. A plain plate cuspid was backed with gold plate and fitted on tbe roof -plate, to wbicli, after determining its proper occlusion, it was secured by hard wax; re- moved, invested, and soldered. It was then put into the tube on the root; the telescoping cap put over the molar; the truss put in position in the mouth, and the whole covered with plaster and marble-dust, contained in a suitable sectional impression-tray,, which enabled me to hold the mass steadily in place until the mix- ture was sufficiently hard to bring away cap and truss and roof- plate all in proper position. A second mixture of plaster and Fig. 471. marble-dust, and a suitable trimming of the first mixture after all was hard, sufficed for the soldering process that resulted in the denture which, when finished, appeared as shown detached at C, rig. 4Y0, and mounted on the cast in Fig. 471. 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 sufficiently to soften the gutta-percha, replacing the denture on its anchorages, and directing the proper closure of the occluding teeth." DR. PARR'S METHODS. Detachahle.—Yig. 472 illustrates a method of this style. The teeth forming the abutments lean toward each other posteriorly and anteriorly over the space to be bridged, as shown on the original model, Fig. 4Y3. The bridge is supported by two shoulders on the abutment crowns, which slide into grooves in DKTACHABLK AND RKMOVABLK BRWr^JJ-WORK. 257 the dummies (Fig. 474). These supporting shoulders and slots are made by shaping two pieces of platinum plate to the form shown in Fig. 475, so that one shall telescope the other. The inner one is then invested on the outside surface and filled in with gold plate. The outer piece is then filled inside with in- vesting 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. Fio. 473. Fig. 474. Fig. 475. Fig. 476 shows a bridge constructed with the attachment de- scribed at one end and a double cap attachment at the other.^ Removable Bridge. — In this style the crowns forming the abut- ments are permanently cemented in position, each section of the bridge between them being removable. The case illustrated in Fig. 477 will serve as a type to give the constructive details. The cuspid and molar crowns are first formed in the usual man- ner. A model from an impression is then made, on which the crowns will appear in the same position as in the mouth. A gold and platinum bar (A, Fig. 478) is then formed between the cuspid and molar. The end for the cuspid is rounded, and that ^ Case of Dr. C. L. Alexander, described page 27, Dental Cosmos, vol. xxxiii. 18 . 258 ARTIFICIAL CROWN- AND BRIDGE-WORK. for the molar flattened. This last may be done by hammering the wire flat or by soldering a piece of clasp plate transversely to it. The two ends of the bar are then fitted in sockets of platinum (B, B). The ends of the bar should be bent and the Fig. 476. platinum sockets placed in such a position against the sides of the crowns that the bar can be easily adjusted and removed. The sockets are next soldered to the sides of the cuspid and molar crowns (A, A, Fig. 477), for which purpose the sockets Fig. 477. and crowns should be removed and invested. The sockets are held in position when the wax is melted out by pieces of iron wire, one end of which, covered with a portion of the investing material, is inserted in the socket, the other end being imbedded in the investment. If preferred, the slot on the side of the molar crown can be made with a piece of platinum adapted over DF/rAt'IIABLE AND REMOVABLE BRIDGE- WORK. 259 the flat piece of gold forming the end of the bar, and then soldering the platinum to the side of the crown, the platinum being stiffened bj flowing the solder over it. At this point the crowns and bar may be adjusted in the mouth, as well as on the model, to insure accuracy. A piece of thin platinum or gold is then perforated and slipped over the ends of the bar, which is jDlaced in position on the crowns, and the platinum or gold Pig. 478. adapted to the form of the attachments, and to the immediately adjacent surfaces of the crowns. These shell forms are made to assure to the ends of the bridge a perfect fit by giving them the shape of the crowns and the attachments on the crowns. To this bar the teeth constituting the bridge are fitted in their respective positions and soldered. Bending either end of the bar slightly (B, B, Fig. 477), or sawing a slit in the cuspid end Fig. 479. of it (Fig. 409), affords the means of holding the bridge firmly in position, although it may be removed and reinserted at the option of its wearer. Fig. 479 shows the inserted bridge. Fig. 480 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 section consists of a cap having a spring flange. The flange enters the socket, which the cap incloses on the top and at the sides. The spring is made by bending open a little the part of the flange marked A. 260 ARTIFICIAL CROWN- AND BRIDGE- WORK. This form of attachment is constriicted as follows: To make the spring flange, two pieces of clasp or spring gold plate about 1^0. 23 U. S. standard gauge, one of them one-half and the other one-fourth of an inch long and from one-eighth to one-quarter of an inch wide, the exact dimensions being governed by the case in hand, are laid together, so that one end of the short piece is nearer one end of the larger piece than the other. The edge of the short piece nearest the end of the longer one is then soldered to it with a hard-flowing solder, the two being held during the operation in a blue gas flame with tweezers, and the end is trimmed square. A little whiting placed between the other edges will prevent the solder from flowing between or joining the pieces there. The short piece of plate is to form the spring, and is left unconnected at one end for that purpose (A, Fig. 481). To Form the Socket. — The spring flange is flrst enveloped once around with a thin piece of platinum, a little deeper than the socket is required. The platinum is then enveloped with one thickness of coin gold plate, ISTo. 32 U. S. standard gauge, about the depth the socket is to be, leaving a ledge of the platinum projecting. The plati- num and gold are next removed and soldered, by holding them in a flame and using very little solder, of a hard- flowing variety, which is placed upon the ledge. The sides and ends of the sockets are then filed level and the socket given a square form (B). To Form the Cap.- — The spring flange having been inserted in the socket, two pieces of the spring gold plate of the same length as the socket are adjusted along its sides, the pieces being cut a little wider than the depth of the socket, so that when adjusted they shall project slightly above it. A piece of thin platinum plate is then adapted to the end of the flange, to the socket, and to the pieces of spring plate, first being perforated to allow the projecting ends of the latter to pass through it. The spring plates and the flange plate are then cemented to the plati- num plate with wax, removed from the socket, invested, and sol- dered (C). DKTACIIABLK AXD REMOVABLE BRIDGK-WORh'. Ogl The sockets must be so placed on the crowns that the springs at the ends of the bridge shall enter them on parallel lines. Their proper relative positions to secure this movement are readily determined by attaching the tops of the spring flanges (either temporarily or permanently) to the ends of a piece of wire of the length of the space to be bridged, which will permit the neces- sary adjustment. The sockets are then soldered onto the crowns. When the bridge teeth or dummies adjoining the sockets have been fitted in position, they are withdrawn with the caps and spring flanges, and soldered to the bar, in the manner described at page 258. The gold caps forming the occluding surfaces of the bridge tooth can usually be fitted over the cap. When the socket is attached lengthwise from labial to palatal side to a gold crown as at A, Fig. 477, the spring metal plate of the flange is best placed on the side toward the crown. In a bridge of this style of the anterior teeth only, — where the abutments form the extremities of the piece, — the ends should be attached to the mesial sides of the crowns forming the sup- ports; but when it also carries teeth posterior to the abutment, and the sections of the bridge ^^- are united together, the attachment should be made on the distal side, the bar supporting the anterior teeth resting in a slot formed on the palatal side of the abutment (Fig. 482). A shell crown on a cuspid can be utilized as a support for this form of attachment. The attachment described can also be used in combination with removable plate bridges. Fig. 483 shows the cast of a lower jaw in which only the left second molar, left cuspid, and right first bicuspid remained. The molar and bicuspid were fitted with gold cap-crowns, and spring socket attachments (Dr. Parr's form) were soldered in proper positions on the crowns, as illustrated. The completed denture in position supported by the attachments is seen in Fig. 484. The under side is shown in Fig. 485. Fig. 486 represents the articulated cast of a case in which a similar form of attachment and a clasp were used. This is illustrated in Fig. 487, which needs no description. 262 ARTIFICIAL CROWN- AND BRIDGE-WORK. Fig. 483. Fig. 484. ^ :r r X > Fyi 18^ DF/PA CIL I BIj /<; . I XD RKMO VA BLE BRIDU E- W()RK. 263 Fig. 488 shoAVs the denture in place. It was constructed of vulcanite, and made for and placed in the mouth of a patient Fig. 48r,. Fio. 481 Fig. 488. exhibited at a clinic of the Odontological Society of Pennsyl- vania, at Philadelphia, in December, 1888.^ DR. WATERS'S METHODS. « Dr. T. S. Waters explains the advantages of his removable plate bridge-work as follows: "In the system I present the denture is retained securely and steadily in the mouth, yet is readily re- moved and replaced at pleasure by the wearer. The pressure and strain are distributed properly over all the structures and tis- sues available for the purpose, and the roots and crowns to which the denture is attached are so prepared that there is no place for the lodgment and retention of food, and when the denture is removed, both it and the mouth can be thoroughly cleansed. Should the roots or other tissues be attacked by disease, thus requiring treat- ment, or should repairs to the mechanism become necessary, the movable bridge-work offers facilities for those purposes not to be found in permanent dentures." ^Dental Cosmos, March, 1881). '■^ International Dental Journal, April 1881), page 197. 264 ARTIFICIAL CROWN- AND BRIDGE-WORK. Dr. Waters thus describes the formation, combination, and application of his devices to cases of removable plate bridge-work : "My devices are three in number, each of which may be used alone, or two of them or all three may be combined and applied Fig. 489. Fig. 490. Fig. 491. i f /^ in the same case, as the position, character, and relation of the teeth and roots remaining in the mouth may seem to indicate. "The iirst is a gold crown fitted to and sliding on a cap attached permanently to the root ' or natural crown. This cap is made high and has on one side a longitudinal groove. The gold crown has soldered on the inside a spring catch, which works in the groove on the cap, and holds the crown firmly in its place. The char- acter of the device is seen in application to the case represented in DETACJIABLE AND KKMOVABLE BRIDfiE-WORK. 205 Fig. 489. Fig. 490 shows the denture in position. Fig, 491 gives the lingual aspect. It will be readily seen that under proper circumstances two or more roots or teeth may be fitted with this device, the gold crown may be soldered to and made a part of the denture, making the whole a piece of bridge-work capable of being removed, cleaned, and replaced at will. The. spring catch regu- lates the firmness of retention.^ Fig. 493. Fig 494 "The next device is the box cap and split post; the box cap being fitted permanently to the root, and the split post being soldered to the plate bearing the teeth. The box cap is the usual cap, with a box or tube soldered to it and extending into the root, the cap end of the tube being open. The split post is so ^Dr. "Waters has patented this invention and donated it to the profession. 266 ARTIFICIAL GROWN- AND BRIDGE-WORK. secured to the denture as to slide snugly into this tube, the firm- ness of retention being regulated by pressing the split slightly open when necessary. This device, like the first, may, under Fig. 495. proper circumstances, be used by itself in any case, as shown in application in Mgs. 492, 493, and 494, in which the whole denture is supported by box caps and split posts adjusted, to the roots of the six anterior teeth. DETACH ABLE AND REMOVABLE BRIDGK-]V'<)I{K. Ofjy "The third device consists in soldering to the side of the gold croM'n covering the natural tooth a split pin or post, which is inserted into the open tube attached to the denture. "As before remarked, these devices may be used singly or in combination in any one case. In one of the dentures illustrated the box cap and split post alone are used; in another, the cap, gold crown, and spring catch are used; in the case illustrated in Figs. 495, 496, and 497 the three are applied, in which the entire denture is attached to and retained by two cuspids, a bicuspid, and a molar. In all this, great care must of course l)e taken in the prej^aration of the roots and natural crowns, to protect them against the action of destructive agents." DR. BONWILL'S METHOD. i The special feature of this method is, the advocacy of con- necting the clasp attachment to the plate with a piece of stout gold and platinum wire on the side of the tooth, offering the least resistance to the insertion and removal of' the clasp. This, for instance, should be on the buccal side of a lower molar if it tips inward or forward. The clasp is thus left free to spring over any portion of the crown out of line. The clasp is surmounted with a flange or spur placed at a point free of the occluding teeth, and the plate is made of lieavy gold plate or of two thin plates soldered together. A description of the following practical cases will explain the method: Fig. 498 is a cast for the first upper bicuspid, right side. A filling of gold was placed in the distal surface of the natural cuspid, with a hole, c, drilled into the filling for the pin c. Fig. 499. The second bicuspid had also a large amalgam filling, around which the clasp was placed, so that it would not show from the mouth. Fig. 499 shows the plate with a tube-tooth' or porcelain crown thereon, Avith pin soldered to the plate. The clasp has a flange attached to it at 7i. -^ is a heavy platinized gold bar, showing how it forms a free attachment between plate and clasp, c is a pin, soldered directly to the plate, which enters the hole in the gold filling shown at c in Fig. 498. Fig. 500 is a skeleton plate with the attachments without the tooth made for the case — left side, lower jaw — shown in Fig. 502. '^International Dental Journal^ vol. xiv, page 94. 268 ARTIFICIAL CROWN- AND BRIDGE-WORK. e and e, Fig. 500, are flanges to prevent the plate pressing too hard on the gum. One rests on the molar independent of the clasp, and the other on the bicuspid. A small spur is placed under the flange that is to rest on the bicuspid to fit in a groove in an amalgam filling shown at d, Fig. 502, to keep the anterior portion of the plate in position. The clasp is connected to the plate at the lingual side bj the bar marked i. Fig. 501 shows the finished case with the artificial crown cemented over the pins or vulcanized on. Fig. 498. Fig. 499. Fig. 500. Fig. 501. Fig. 502. Fig. 503. Fig. 503 shows the replacement of a second bicuspid, right side, lower jaw. The bar i is soldered to the plate and clasp on the buccal side of the first molar. The artificial tooth is made entirely of gold, and the flange resting on the first bicuspid is soldered directly to it. The anterior surface of the gold tooth is made concave to fit the distal surface of the first bicuspid, and so prevent lateral movement. In this case a gold crown is used as the artificial tooth, as it facilitates the soldering, adds to the strength, is easy to repair, and is not seen. The rear flange, which rests on the molar, might have been soldered to the gold tooth also, and less strain would thus come on the clasp. CHAPTEK XIII. REMOVABLE BAR-BRIDGES. In removable bar bridge-work the bar is permanently attached to the abutments, and spans the space between them independent of the bridge. The bridge portion proper of the denture, con- sisting of the artificial teeth (dummies), is formed with a slot, or a countersunk base, into which the bar slides as the bridge is placed in position. EiG. 504. In the case represented in Fig. 504, one end of the bar is attached to the gold molar crown and the other end anchored in the cuspid with a gold filling. The bridge section fits over the bar as illustrated. The process of construction as given by Dr. J. G. Morej is as follows : The molar is capped with gold. A flat bar of iridio-platinum, about ISTo. 12 gauge and one-eighth of an inch wide, — ^the width being regulated by the needs of the case in hand,- — is fitted to the space. One end of the bar is fitted in the anchorage cavity in the cuspid, and the other end to the gold molar crown. A slot ia then cut in the bar, beveled slightly toward the gum (Fig. 504). A piece of gold clasp plate, about ^o. 28 gauge, the width of the slot, is cut and shaped in the form of a clamp to fit over both sides of the bar in the slot. The end of the bar is then sol- dered to the gold crown. The bar must be placed far enough •IC,'.) 270 ARTIFICIAL CROWN- AND BRIDGE-WORK. toward the palatal side to leave space for the artificial teeth. Porcelain teeth are liext fitted in place, backed with thin plati- num, cemented with Avax to the clamp-shaped piece of gold, and removed from the bar. Teeth and gold clamp are then in- vested and soldered together. In investing, one end of a narrow strip of sheet iron is inserted in the slot of the gold clamp, and the other end extended into the body of the investment, to hold and steady the gold clamp in position, while the gold solder is flowed between it and the porcelain tooth after the wax is re- moved. When finished, the point of the gold clamp is to be bent a little inward to secure and fasten tlie bridge section when slid into position on the bar. Firmness is also obtained by the slightly beveled form given to the slot in the bar. Kg. 505 gives a sec- tional side view of the bridge-tooth and bar. Fig. 506 represents the bar and bridge section in position.^ Dr. Morey's method of constructing a double bar-bridge with a removable molar or dummy is as follows : The bar is formed as seen in Fig. 507. "A countersunk molar is ground and shaped as seen at A and B, Fig. 508. To the base of the molar and up in the slot is shaped and fitted the shell C, made of a very thin piece of gold and platinum crown-metal by 1 A description of a removable bar-bridge, as given by Dr. J. G. Morey, was presented in the first and second editions of this work. A more extended descrip- tion of bridge-work on this principle is given in the later editions, as many mem- bers of the profession seem to favor the various methods it involves. In England the method is designated the " Gartrell Bridge," having been introduced there by Dr. Gartrell, an American dentist, formerly of New York, now practicing at Penzance, England. The models of a case similar to the one illustrated in Figs. 504 and 506 were exhibited at the Ninth International Medical Congress at Washington and pre- sented by Dr. Morey to the author in 1887, and are still in his possession ; but, as the method did not favorably impress him at ihe time, further description of it than had been given was withheld. — G. E. i JIKMO VA r,LE I:A li-l'.l(lD32. the telescoping crown. When desirable, the ^seamless' collar can be strengthened, after being adapted to the conformation of the- crown, by investing and flowing solder over the outer surface; or by fitting the next larger size of collar around the first, invest- ing and soldering the two together. "The other appliances devised for this system are, a reducing- plate or contractor, a pair of collar pliers, and a hammer. "The contractor (Fig. 532) contains holes which are comple> mentary in shape to the mandrels. The mandrels being applied 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 size than is shown in the mandrels. With this appliance collars TiiF. ma.\'diii:l system. 283 C3 a a M c (Z0§ as as as as a§ I Fk;. 633. a« w (D 9> (t> \S Vi »< o o o o o O O O o o 284 ARTIFICIAL CROWN- AND BRIDGE-WORK. can be evenly and accurately reduced in size at the edges, with- out burring or buckling. The illustration is actual size. "The collar pliers (Fig. 534) are for contouring the collars to shape, one beak being made convex and the other concave to correspond. Fig. 535 is a mallet or hammer, with steel face and horn peen. Fig. 534. Fig. 535. 1 ! "To select and adjust a suitable collar for a crown or root, take a piece of binding- wire (ISTo. 28, 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 mth one finger, twist the ends with a pair of flat-nose pliers until the wire clasps the neck closely at every point (Fig. 536). Where Fig. 536. Fig. 587. there are irregularities in the contour of the tooth, it is necessary to press the wire into them with a burnisher. The ring thus formed will show the exact size and shape of the neck of the tooth. Eemove the ring carefully, lay it on the lead anvil, put over it a piece of flat metal, and with a smart blow from a hammer drive the wire into the lead (Fig. 537). Upon remov- ing the wire, an exact impression of the ring will be left in the anvil. THE MAN DUEL SYSTEM. 285 "JSText, 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. 533), which show the inside diameters of the various sizes. Should none of these correspond exactly, take preferably the next size smaller. Having selected the collar, fit to mandrel with the peen of the hammer, holding it upon the lead, and using a slight pushing force to help in stretching and forming it (Fig. 538). Having driven the collar Fig. 539. Fig. 538. to form, remove it from the man- drel 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. "If the collar or band has been accidentally stretched too much, or if for any reason it is too large, its root-end can easily be reduced to the proper size by 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. 539) until the proper reduction is made." The collar is next trimmed to correspond to the shape of the gum-margin. The cap section to represent the grinding-surface is then added by one of the methods described on pages 83 and 88. The grinding section, in cases of pulpless roots, may be con- structed of porcelain by the use of porcelain cusp-crowns, such as are shown in Fig. 540. Where porcelain is to be used, place the collar in position, and having ascertained how far it should go down on the root, remove it, and with the small spring punch in the collar pliers form projections on the inside of the collar at proper points to serve as stops, which, by resting on the top of the root, will prevent the collar from being forced farther down on 286 ARTIFICIAL CROWN- AND BRIDGE-WORK. it than is desirable (Fig. 541). ISText fit and cement screw-posts in the root-canals, leaving the ends projecting in the space inside the collar, and cement the collar on the root, filling about two- thirds of the depth of the collar. Select a suitable cusp-crown, of the form illustrated in Fig. 540, and fit to inside of end of collar. If too long, shorten the cusps or reduce the length of the collar. F]G .')40 Fig. 541. Ftg. 542. When articulated, form a small square shoulder around the line of the edge of the porcelain with a corundum disk. Fill the remainder of the inside of the collar with cement, mixed to a cream-like consistence, and set the porcelain in position. If there are antagonizing teeth, the mere closing of the patient's jaws will force the cusp to position in posterior teeth. In the front, or where there are no occluding surfaces, force to position with the mallet or a piece of wood as a driver. Fig. ;j43. Porcelain cusp-crowns of the form shown in Fig. 542 are in- tended for use where the labial side of the collar is cut away, and that section is to be represented by the porcelain as shown in Fig. 543. CHAPTEE XVI. THP] HOLLINGSWORTH SYSTEM. The object of the "Hollingsworth System" is to systematize and simplify the process of construction of that style of cro^vn- and bridge-work in most general use. To this end the form of procedure is concisely outlined and some special methods and ap- pliances introduced. The last mentioned consists of a set of two hundred and four forms of solid metallic grinding-surfaces of bi- cuspids and molars, termed in the description "cusp-buttons," for use in forming grinding-surfaces for crowns or dummies; thirty- six facings for shaping the labial surfaces of all-gold bicuspid and molar dummies, and forty for labial and palatal surfaces of all- gold incisors and cuspid crowns. These collectively are to be seen in the case illustrated in Fig. 544; likewise (Fig. 544 A) some other appliances contained in the set. A brief description of the principal methods in connection with the use of the appli- ances is here given. TO MAKE A GOLD CROWN (BICUSPID OR MOLAR). Make a band to fit the root in the ordinary way. Place the band in the mouth (see Fig. 545), and cut off on a line where the adjoining teeth begin to turn to form the cusp (see c, Fig. 545). Place a small piece of wax inside the band to assist in holding the cusp-button, which should be selected to fit the circumference of the band, to articulate, properly, and to correspond in shape with the other teeth (see h, Fig. 545). Remove the button, and place it on the molding-plate with the grinding-surface up (see Fig. 546). Place the small rubber ring around it, pour in a suf- ficient quantity of Melotte's metal to nearly fill the ring (Fig. 547). As soon as the metal sets, chill the surface by dipping in water for a moment, and then remove the rubber ring. When the heat l)egins to return to the surface, a quick rap of the die on 287 288 ARTIFICIAL GROWN- AND BRIDGE-WORK. Fig. 544. yi jf^^^'V t; Set consists of the following : 204 Cusps, 36 Facings, 40 Forms for Incisors and Cuspids, in folding case, 1 Casting Plate (A), 3 Rubber Rings (E, F), 1 Carbon Rod (B), 1 Sheet Asbestos 10x7 in, (C), Boxof Annealed Copper Strips (D). (See Fig. 544 A.) the bench will cause the cusp-button to drop out and leave the mold ready to form the gold cusp. ISTow take a piece of lead, for instance a lead hub, and with a hammer drive into the Melotte- metal die (Fig. 548) to form the counter-die (Fig, 548, d). Till-: II<)IJ,IN<1S\\'()I{TII Si STEM. 289 Fig. 545 Fig. 54 EiG. 546. Fig. 548. Fig. 549. Fig. 550. Fig. 551. XII (4 20 290 ARTIFICIAL CROWN- AND BRIDGE-WORK. Anneal the gold plate, and start the swaging process by coax- ing the plate into the die by hand-pressure (Fig. 549), using a piece of wood which makes a depression for the lead counter- die to rest in. Then place the counter-die on the gold plate (Fig. 550), and drive to a fit. Cut the surplus metal from the hollow cusp with shears (Fig. 551), filing up the edges when necessary, and rub down the under surface on a smooth file until it fits the band made for it (Fig. 545). Wire the cusp and crown together (Fig. 552), place flux and solder in the cap, and hold over a lamp until soldered. Then finish in the usual way. Fig. 552. Fig. 553. Fig. 554. c Note. — If the forms of cusp-buttons do not afford one which articulates perfectly, the diffi- culty is easily remedied by taking the button which most nearly answers, and building up the cusps with Melotte's moldine (Fig. 553). If a band is accidentally cut too short, it can still be utilized. Place moldine upon the molding- plate, put the cusp-button upon it, press down and adjust to make up the deficiency of the band, cutting away the surplus moldine. This will of course throw the soldering line a little farther up on the crown (Fig. 554). TO MAKE SOLID GOLD CUSPS. Scrap gold can be utilized for making a solid gold cusp by casting in asbestos by the following method: After selecting the desired cusp-button, instead of making a mold in Melotte's metal, as before described, take a piece of asbes- tos board about one inch square and one-fourth inch thick, moisten it, and with a hammer drive the cusp-button into it, flush with the surface of the button. (See Fig. 555, a.) Remove the but- THE ITOLLIXasWOJiTH srSTEM. 291 ton, and dry the asbestos in a flame (Fig. 655). "When perfectly dry, place a sufiicient quantity of gold scraps in the die made in the asbestos, and direct the blow-pipe flame upon it until melted, in- clining the carbon stick, as shown, against the die for the double purpose of confining the heat and warming up the carbon stick. When the gold is fused into a button, press it into the die with the carbon stick (Fig. 556). Avoid the use of flux when ivorhing with asbestos. To build up a cusp to make a perfect articu- FiG. 556. Fig. 555. lation, in this method, sealing-wax must be used instead of mold- ine, as in swaging the cusp. Warm the button before applying the wax, and with a warm instrument shape the cusp as desired. TO MAKE GOLD CROWNS (CENTRALS, LATERALS, AND CUSPIDS). Select from the forty different forms in the set that which is most suitable to the case in hand (Fig. 557). (The forms are in pairs, showing labial and lingual surfaces.) Take the meas- urement of the root to be crowned with one of the annealed copper strips, binding the strip around the tooth with pliers (Fig. 558, a). Take this measurement and cut it through the center (Fig. 558, &), then bend the respective halves over the lingual and labial forms selected, at the necks, with the cut ends of the strips Testing on the flat of the plate (Fig. 559). If the measurement is larger than the form selected, build the latter up vdth moldine until the space between the form and strip is filled (Fig. 559, &). Avoid getting moldine on the approximal surface. Remove the strips, dry out the moldine, by passing through a flame a few times, then place the form on the molding plate with a rubber ring around 292 ARTIFICIAL CROWN- AND BRIDGE-WORK. it. Pour Melotte's metal into the ring as in forming the molar or bicuspid cusp, which makes a die of the two sections, lingual and labial. Make a lead counter-die and proceed as directed in the making of a molar cusp, swaging both sections (Fig. 560). Trim off the surplus plate (Fig, 561), and square the opposing edges of the two sections by rubbing them over a dead smooth file. Fig. 557. Fig. 558. Pig. 559. Fig. 560. Fig. 561. Fig. 563. Fig. 564. Bind the two sections together with wire with sufficient solder and flux inside (Figs. 562 and 563), and proceed as in soldering an ordinary band. With a small mechanical saw cut off the upper portion where the tooth begins to slope back (about the dotted lines in Fig. 563). This leaves the crown as shown in Fig. 564, approximal and labial views. Drive on the root. If THE NOLLINOSWO/mr SYSTEM. 293 too small, place on the horn of an anvil and enlarge bj hammer- ing; if too large, band the root in the same manner as for a Rich- mond crown, grinding the tooth to fit. TO INSERT A PORCELAIN FACING. Make the gold crown as described. Select a porcelain facing suitable for the case (Fig. 565). Place the crown on the root in the month, and with an excavator mark on the face where Fig. 565. Fig. 568. Fig. 567. Fig. 572. Fig. 573. Fig. 574. the porcelain is to appear. Remove the crown and saw out, so that the facing will fit loosely. With a knife bevel the inner edge or seat for the facing (Fig. 566). Grind the facing to fit (Fig. 567). Back up the facing with !N^o. 34 or 36 gauge pure gold, punching holes in the backing for pins, annealing as re- quired to readily conform it to the tooth (Figs. 568 and 569). With a sharp knife cut a barb on each side of the pins in the facing, and press the barbs against the backing (Fig. 570), which keeps the backing in place. Burnish down the edges well, being careful not to let the backing overlap the facing. Place the facing in the space prepared for it in the crown (Fig. 571), and bind the two together (not too tight) with wire, wrap- ping the wire directly over the facing with asbestos to prevent 294 ARTIFICIAL CROWN- AND BRIDGE-WORK. discoloration of the porcelain, Flux and solder by holding over a lamp as in case of a band (Fig. 572). Finish in the usual way. If it is desired to use a platinum pin for anchorage, as, for instance, a Logan pin, bend the pins in the facing sufficiently to clamp the anchorage pin, and insert the pin through the gold crown (Fig. 573), finishing as before described. Fig. 574 shows a finished crown so made. TO MAKE THE GRI NDING-SURFACE OF A BRIDGE IN ONE CONTINUOUS PIECE. After having crowned the teeth for the attachment of the bridge, take a bite in modelling compound, remove the com- pound, place the crowns in their impressions, make a cast of Fig. 575. sand and plaster, and place on an articulator; now put moldine between the abutments instead of wax, and get the articulation with cusp-buttons the same as you would for plate teeth (Fig. 575). Then, to remove the buttons without destroying the articu- lation, make a cup by pouring Melotte's metal, as cool as it will flow, on the face of the cusp-buttons. Heat the pouring lip of the ladle and use it to smooth out the half -congealed metal, much as you would a soldering iron (Fig. 576). Then place a thin coating of moldine upon the molding plate. Remove the cup from the articulator with the cusp-buttons in place (Fig. 576, a). Transfer the cusps by inverting the molding plate (Fig. 577), and turn the cusp-buttons out upon the moldine on the plate with the grind- ing-surface up (Fig. 577, a), and they will occupy the same rela- tive positions as when on the articulator. !N"ow place the large rubber ring around the buttons on the plate, and proceed to make a die with Melotte's metal, as before described (Fig. 578). When cool, remove the buttons and coat the face of the die with whiting. Invert the die and raise the 77//'; IIOIJJNaSWOIlTlI SYSTEM. 295 rubber ring sufficiently high on it, and make a counter-die with the same metal by pouring as cool as possible (Fig, 579). This gives the male and female dies with which to swage the con- tinuous grinding-surfaces. Then proceed to swage the gold plate in one piece (Fig. 580), annealing as often as necessary. Trim Fi(i. 57G. off the surplus plate (Fig. 580, a), and place in position on the articulator. Cut the cusps out on the buccal face to avoid show- ing the gold (Fig. 581), grind the porcelain facings to fit the cusps, and back with gold, ITo. 34 or 36, letting the gold come to the cutting-edge, the same as in a single crown, as before described. If there is a space between the cutting-edge and the porcelain, place a little wax in the joint to keep out the plaster invest- ment, invest, remove the wax from between the joints, flux, and solder. FACINGS FOR MAKING ALL-GOLD BRIDGE. If it is desired to make an all-gold bridge, select the proper facings from the set, make a die of Melotte's metal, and swage up, the same as in the continuous bridge before described, and mount gold facings in place of porcelain. CHAPTER XVII. CEOWN- AND BRIDGE-WOKK COMBINED WITH OPEEATIVE DENTISTRY IN DENTAL PROSTHESIS. In croAvn- and bridge-work, artistic skill on the part of the operator can frequently be most advantageously displayed in the conduct of operations. An appearance of symmetry should as much as possible be imparted to the upper front teeth. The contour of the arch, the labial aspect and length of the teeth, singly and collectively, on one side of the mouth in comparison to those on the other, should be observed and studied. That most appreciable results are thus possible of attainment is demonstrated in the following two cases : In the case presented in Fig. 582, that of a gentleman of about sixty-two years of age, is to be seen the irregularity of Fig. 582. the teeth present and the unevenness of their incisive edges and occluding surfaces, the condition having arisen from the combined effects of decay, erosion, mechanical abrasion, and mal- occlusion. The operations performed were as follows: On the right side the second molar was restored by filling; the first molar and the bicuspid crowned with gold; the cuspid and cen- tral were lengthened with solid gold tips, each tip being an- 296 Ol'ERATIVK DKNTISTRV WITH C'liOWX- AND BJtlDdE-WOJiK. 997 chored with three pins; and the lateral was crowned — at the request of the patient — with gold. On the left side the central was crowned with a gold crown with porcelain front, the cuspid shortened and filled on the palatal side, and the bicuspid crowned with gold and the spaces bridged. Guided bj a line at right angles to the median line (Figs. 582 and 583), the teeth and crowns on one side were formed to cor- respond as much as possible in length, shape, and appearance to those on the other. Those teeth affected with pyorrhea were treated. The results of these combined operations, conducted with a view to the artistic as well as the restorative effect, are plainly to be seen in the finished case illustrated in Fig. 583. Fig. 583. What can be quickly accomplished by judicious trimming and shaping of the teeth, in combination with other operations, is well illustrated in the following case: The patient's upper front teeth presented the appearance shown in Fig. 584. The right central and left lateral were pulpless. The central was badly discolored and the lateral slightly so. The central had been bleached, but in a few years gradually resumed its former appear- ance. The other teeth with living pulps and light in color con- trasted most unfavorably. The incisive edges of the centrals were affected with atrophy. The laterals, especially the right one, were elongated from pyorrhea. i The length of the incisors contrasted unfavorably with the cuspids. The patient, a lady, was so an- noyed at the appearance of the teeth, which she considered a permanent disfigurement, that she had positively decided to have all the incisors crowned or extracted and artificially replaced. A most satisfactory compromise was effected, enaljling the patient to 298 ARTIFICIAL CROWN- AND BRIDGE-WORK. avoid either of these extreme measures by tlie performance of the following operations: The pyorrhea was treated, the left lateral was bleached and refilled, the right central natural crown excised and an artificial one (style described on page 113) inserted, and the atrophied incisive edge of the left central removed, all the incisive ends of the other teeth being trimmed to properly corre- spond in length and shape. The improvement effected is ap- parent in the illustration of the finished case, Fig. 585. Fig. 584. V Fig. 585. The results in dental prosthesis which can be accomplished by a combination of operations on the natural teeth with crown- and bridge-work commend the plan strongly to the experienced practitioner. A few more cases are adduced in illustration. A case which was interesting, owing to the conditions pre- sented and the various operations connected with it, is illustrated in Fig. 586. Tig. 587 shows the methods and operations prac- ticed, and Fig. 588 the case completed. The upper front teeth show the effects of abrasion on the in- cisive edges and occluding surfaces. The bicuspids and molars were affected with pyorrhea alveolaris. The four incisors and the left cuspid were pulpless, and alveolar abscess existed at the roots of three of the incisors. The abscesses and root-canals were properly treated. Gold collar crowns with porcelain fronts, hav- OPERA TIVE DENTISTR V WITJI CliO WN- AND BRIDGE- WORK. 299 ing flat incisive edges wliicli perfectly protected the porcelain fronts and slightly opened the bite, were made for the incisors and left cnspid (Fig. 587). The bicuspids and molars were placed Fig. 586. in as hygienic a condition as possible by treatment. On the left side a dummy bicuspid with a bar which fitted in a slot formed to receive it in the occluding surface of the second bicuspid was attached to the cuspid crown. When the cuspid crown with the dummy bicuspid was cemented in position, the bar was an- 300 ARTIFICIAL CROWN- AND BRIDGE-WORK. chored in the slot in tlie second bicuspid with amalgam. The cuspid root being very firm, stability was thus imparted to the natural bicuspid, which was quite loose because of absorption of its socket. On the right side the second bicuspid was entirely capped with a gold seamless crown. On the anterior side of this gold crown an artificial tooth was attached as a dummy first bi- cuspid, with a bar extending from its anterior side and fitted into a slot formed in the incisive surface of the natural cuspid crown. From the posterior side of the second bicuspid gold crown a bar was extended backward into the side of the molar. When the gold crown was cemented in position on the second bicuspid, the anterior bar was firmly anchored in the cuspid with a gold filling, which also lengthened the incisive edge, and the posterior bar was fixed in the molar with amalgam. The reasons for this form of construction were : The second bicuspid was very Tig. 588. loose in its socket, and the molar, though comparatively more stable, was also similarly affected. The attachment of the bar in the cuspid supported the dummy bicuspid and steadied the second bicuspid, and the extension of the posterior bar into the molar likewise afforded additional support to the bicuspid. The pulp of the molar being exposed, was devitalized, removed, and the canal properly filled. Fig. 588 shows the completed case.^ 1 During the presence of the patient in the writer's office, four years after the worlv was completed, the operations were examined by members of the profession. OPERATIVE DKNTlSTRy WITH CROWN- AND BRIDGE-WOJtK. 3OI The lower teeth, in comparison with the upper, were but slightly abraded. The cuspids and one of the incisors were tipped with gold. The molars on the left side were absent, so that bridge- work on the upper jaw on that side between the bicuspid and molar would have been to no purpose. In the case presented in Fig. 589 the operative procedures were confined to the upper jaw, the lower teeth of the patient being in good condition. The bicuspids and the first and second molars of both sides of the upper jaw had been lost many years before, and the incisors and cuspids showed the effects of extensive abra- sion. The occlusion was sustained and the principal part of mas- FiG. 589. tication performed by the incisors, as the third molars had been forced backward and antagonized only very slightly on one side. The patient, a gentleman, had had a plate inserted, to the pres- ence of which he had vainly endeavored to accustom his mouth. The abrasion of the incisors and cuspids was of the rapidly pro- gressive character. These teeth, were contoured with gold foil to the form shown in Fig. 591, and a wire post was inserted in the right lateral, which was pulpless. At the occluding section of and pronounced apparently in as perfect condition as when lirst completed. The treatment of the teeth affected with pyorrhea and the support imparted to them by their attachment to the other firm teeth and to one another had apparently checked the disease, and the affected teeth appeared to he more secure in their sockets than before the insertion of the bridge-work and crowns. 302 ARTIFICIAL CROWN- AND BRIDGE-WORK. each filling, the layer of gold, after being packed with the plugger, was additionally condensed and hardened with a Herbst agate- point burnisher to enable it to better resist the aggressive force of the lower teeth. The third molars were capped and length-, ened with gold crowns, the lines of their sides being made parallel, to admit of a proper adjustment of the supporting collars for a Fig 590 removable plate bridge, by adding gold on their external sur- faces. The plate bridge was employed because of the space be- tween the abutments, which suggested the idea of utilizing the alveolus to assist in supporting it. A narrow shoulder was formed on each crown to support the collars. The attachments to- the cuspids rested by means of a little shoulder on the occluding OPERA Tl VK DENTISTIi i ' WITH (JRO WN- A ND BRID:' COLUMBIA UNIVERSITY LIBRARIES This book is due on the date indicated below, or at the expiration of a definite period after the date of borrowing, as provided by the library rules or by special arrangement with the Librarian in charge. □ ATE BORROWED DATE DUE DATE BORROWED DATE DUE 1 sm' % «§ 1 Cas (747) MlOO A Practical lre,,,,eo.,,,, ,^,3, „^^ 2002449811 RK666 Evans Practical treatise on artificial crown- work. Kvl 1900 J BINDERY ON PERSONAL RESFRVE S? 1\^ \ T:::^T> af f$K^^^ ^1