in ttje Citj> of i^ebj |9orr ^cfjool of Bental anb 0vslI ^urgerp 3^eference %ihvaxy ESSENTIALS OF OPERATIVE DENTISTRY Digitized by the Internet Archive in 2010 with funding from Open Knowledge Commons http://www.archive.org/details/essentialsofoperOOdavi ESSENTIALS OF OPEEATIVE DENTISTRY BY W. CLYDE DAVIS, M.D., D.D.S. DEAN AND PROFESSOR OF OPERATIVE DENTISTRY AND TECHNIC, LINCOLN DENTAL COLLEGE, LINCOLN, NEBRASKA. SECOND REVISED EDITION ST. LOUIS C. V. MOSBY COMPANY 1916 ' ! f Copyright, 1916, by C. V. Mosby Company Press of C. V. Mosby Company St. Louis PREFACE TO SECOND EDITION. Ill presenting the second edition of this work, it is the aim of the author to follow the plan of the first edition, in that it be concise and vet cover a wide field in operative dentistry. The book has been thoroughly rewritten and extensively illus- trated. Four new chapters have been added, several have been materially enlarged, and others eliminated entirely in this edition. There is a complete rearrangement of the chapters which it is believed will more nearly coincide with the progress of the stu- dent through his technical work and the operatory. W. C. D. PREFACE TO FIRST EDITION. In the preparation of this text-book it has been the author's aim to meet a demand in dental college work for a treatise on operative dentistry which is sufficiently condensed to enable the student to master its contents in the comparatively short college terms at his disposal. The subject matter selected is that w^hich is generally taught by the instructors styled as "Professor of Operative Dentistry." From a study of these teachers' courses of instruction it would seem that the definition of Operative Dentistry as commonly used today would be "That branch of dentistry which treats of the mechanical procedures performed within the oral cavity looking to the salvage of the teeth." However, it has seemed wise in several instances to go beyond the exact limitations of this definition to get a better correlation of subjects. The arrangement of the subject matter is different from that usually found, but is in accordance with the usual line of progress of dental students. The author claims little originality in the essentials presented, having gleaned the facts from the writings, teachings and utter- ances of our greatest educators. The "quiz-explanation" method of teaching is the one most in vogue in the leading universities as productive of the most work on the part of the classes taught, and at the same time giving the tutor more freedom for the expression of opinions to give individuality to his course of instruction. An effort has been made to so publish the "Essentials of Oper- ative Dentistry" that it would serve as a foundation for this quiz course as well as be suggestive to the teacher for a more full explanation, and, at the same time, encourage the student to ex- tend his studies to more voluminous reference books, when time would permit, for an explanation in greater detail. The author is much indebted to his co-laborer, partner and wife, Mattie M. Davis, D.M.D., for valuable assistance in connection with the publication of this volume. W. C. D. CONTENTS PART I. CHAPTER I. Page Instrument Nomenclature 17 CHAPTPJR II. Cavity Nomenclature 21 CHAPTER III. Cavity Preparation. (General Considerations.) 29 CHAPTER IV. Gaining Access 31 CHAPTER V. Outline Form 34 CHAPTER VI. Resistance Form 38 CHAPTER VII. Retention Form 40 CHAPTER VIII. Convenience Form 42 CHAPTER IX. Removal of Remaining Carious Dentine. — Finishing Enamel Walls. — Toilet of the Cavity 44 CHAPTER X. Management of Pit and Fissure Cavities. (Class One.) 48 CHAPTER XI. Management of Pit and Fissure Cavities. (Class One, Concluded.) . . 52 CHAPTER XII. Management of Proximal Cavities i\ liicusJMus and Molars. (Class Two.) 58 CJIAPTER XIII. Eargk i'Roxi.MAL Cavitiks Exuangioking tmk Pulp. (Class Two, Con- tinued.; 65 y 10 CONTENTS CHAPTER XIV. Page Management of Proximal Cavities in Incisors and Cuspids Not Involv- ing THE Angle, (Class Three.) 72 CHAPTER XV. Management of Proximal Cavities in Incisors Involving the Angle. (Class Four.) 78 CHAPTER XVI. Management of Cavities in the Gingival Third. (Class Five.) .... 93 CHAPTER XVII. Management of Abraded Surfaces. Occlusal and Incisal. (Class Six.) 96 CHAPTER XVIII. Cavity Preparation for Gold Inlays 98 PART 11. CHAPTER XIX. The Making and Setting of a Gold Inlay 112 CHAPTER XX. Manipulation of Cohesive Gold in the Making of a Filling 123 CHAPTER XXI. ■ Manipulation of Cohesive Gold in the Making of Fillings by Classes . 129 CHAPTER XXII. Finishing Gold Fillings 137 CHAPTER XXIII. Manipulation of Amalgam in the Making of a Filling 139 CHAPTER XXIV. The Use of Cements in Filling Teeth 146 CHAPTER XXV. Manipulation op Silicate in the Making op a Filling 148 CHAPTER XXVI. The Use op Gutta-Percha in Filling Teeth 164 CHAPTER XXVII. Tin as a Filling Material 166 CHAPTER XXVIII. Combination Fillings 169 CONTEXTS 11 PART III. CHAPTER XXIX. Page EXAMINATIOX OF THE MOUTH LOOKING TO DEXTAL SERVICES 174 CHAPTER XXX. The Alleviation of Dental Pains 177 CHAPTER XXXI. Prophylactic Treatment of the Mouth 180 CHAPTER XXXII. Exclusion of Moisture 187 CHAPTER XXXIII. Treatment of Hypersensitive Dentine 195 CHAPTER XXXIV. Protection of the Vital Pulp 204 CHAPTER XXXV. Pulp Devitalization and Removal 211 CHAPTER XXXVI. Management of Putrescent Pulp Canals 219 CHAPTER XXXVII. The Filling of Pulp Canals 225 CHAPTER XXXVIII. Management of Children's Teeth 229 CHAPTER XXXIX. Extraction of Permanent Teeth 233 CHAPTER XL. Extraction of Temporary Teeth 269 CHAPTER XLL Local and Regional Anesthesia 275 CHAI'TKR XLIL The i;se of Fused Porcelai.v i.v Fijj,ing Teeth 293 CHAPTER XLIII. Preparation of Cavities for Porcelain I.vlays 29G CIIAI'TER XLIV. The Constbuctio.v a.nd I'LAcixr; ok a Porcelain Inla.y 300 ILLUSTRATIONS FIG. PAGE 1. Defects in enamel 21 2. Defects in enamel 22 3. Smooth surface decay 23 4. Smooth surface decay 23 5. Class One cavities tilled 24 6. Class Two cavity tilled 24 7. Class Three cavity filled 25 8. Class Four cavity filled 25 9. Class Five cavity filled 25 10. Bisected molar in which a mesial Class Two cavity has been cut and line angles indicated 26 11. Bisected molar in which a mesial Class Two cavity has been cut and point angles indicated 26 12. Diagram of tooth, giving angles and surfaces 27 13. Technic group illustrating outline form 35 14. Another view of cavities illustrated in Fig. 13 35 15. Fillings in place in cavities shown in Figs. 13 and 14 36 16. Another view of fillings shown in Fig. 15 36 17. Complex Class One cavity prepared 50 18. Class One filled. Cavity shown in Fig. 17 51 19. Large Class One cavities prepared 53 20. Class One filled. Cavities shown in Fig. 19 54 21. Lingual pit cavities 55 22. Class One filled. Cavities shown in Fig. 21 56 23. One of the few eases in which the step may be omitted in Class Two cavities 60 24. Class Two cavities in molar and bicuspid suitable for cohesive gold or amalgam 61 25. Class Two filled. Cavities shown in Fig. 24 62 26. Fillings shown in Fig. 25 contacted, illustrating the marble contact . . 63 27. Large Class Two cavities in non-vital teeth restoring part of the occlusal surface for the protection of weakened walls 67 28. Class Two filled. Cavities shown in Fig. 27 67 29. Mesio-occluso-distal cavities in molar and bicuspid, vital teeth .... 68 30. Mesio-occluso-distal fillings. Cavities shown in Fig. 29 68 31. (A) First superior molar, non- vital, restoring the lingual cusps. (B) Second superior bicuspid, non-vital, restoring the entire occlusal surface 69 32. Class Two filled. Cavities shown in Fig. 31 69 33. Class Three cavities filled 73 34. Drawing to illustrate the retention at the incisal angle of Class Three cavity 75 35. Class Three cavities prepared for cohesive gold 76 36. Class Three filled. Cavities shown in Fig. 35 76 37. Drawings to illustrate the principle of the lever in the dislodgement of fillings of the Fourth Class, plan one 79 38. Drawings to illustrate the principle of the lever in the dislodgement of fillings of the Fourth Class, plans one and two 80 39. Drawing to illustrate the difference in the directions the point angle fillings take in tipping to exit with various fillings 82 12 ILLUSTRATIONS 13 FIG. PAGE 40. Drawings to illustrate the importance which should be given to the proper placing of the incisal point angle in fillings of Class Four, plan two 83 41. A study iu the proper placing and depth of the gingival angles ... 84 42. A study of the planes in which the gingival angles should be laid . . 84 43. Cavity of Class Four, plan one, for cohesive gold 85 44. Class Four, plan cue, cavity filled 85 45. Shows incisal outline in Class Four, plan one, fillings with direct occlusion 86 46. Cavity of Class Four, plan two, for cohesive gold 88 47. Class Four, plan two, filled 88 48. Cavity of Class Four, plan three, for cohesive gold 89 49. Class Four, plan three, filled 89 50. Cavity of Class Four, plan four, for cohesive gold 91 51. Class Four, plan four, filled 91 52. Cavity of Class Four, modified plan three, for cohesive gold in the distal of the superior cuspid 92 53. Class Four, modified plan three, filled 92 54. Cavities Class Five for cohesive gold or amalgam 93 55. Class Five filled 94 56. Cavities of Class One for gold inlays 101 57. Class One inlay in position showing gold wire cast iu tlic filling . . . 102 58. Cavities of Class Two for gold inlays 103 59. Cavity of Class Three for gold inlay, lingual approach 105 60. Inlay shown in Fig. 59 partly in place 105 61. Cavity of Class Four, plan one, for gold inlay 106 62. Class Four, plan one, inlay in position 106 63. Cavity of Class Four, plan two, for gold inlay 107 64. Class Four, plan two, gold inlay in position 107 65. Cavity of Class Four, plan three, for gold inlay 108 66. Class Four, plan three, inlay in position 108 67. Cavity of Class Four, plan four, for gold inlay 109 68. Class Four, plan four, showing cavity side of pattern with pins . . . 109 69. Class Four, plan four, inlay in position before removing wire loop . . 109 70. Cla.ss Five cavity and inlay 110 71. >Siiows the necessary amount of metal for adecjuate protection of abraded surfaces, when opening the bite 110 72. Largo restoration in non-vital ease 113 7.'i. Home of the methods by which inlays may be given retentive form in large decays and non-vital cases 115 74. Starting cohesive gold, first plan 130 75. Starting cohesive gold, second plan 131 76. Starting cohesive gold, thii'd plan 132 77. Burnishing back excess golil foil in covering the gingival maigin . . 133 78. Covering tlie giiigivo-lingual angle with cohesive gold 134 79. Suitable cavities for the use of silicate fillings 149 80. A Class One cavity on the labial of a central incisor properly prepared for a silicate filling 149 81. Extensive Class Tliree cavity ])iit\H'i]y prepared for a silicate filling . . 150 82. A Class Five and a Class Three cavity suitable for the use of silicate as a filling ." 150 83. A Class Five cavity jtrojterly (irepared for a silicate filling 151 84. A Class Three cavity, lingual af»itroacli, properly preparcnl for a silicate filling ..." 151 85. A small Class Three cavity, laiiial approach, properly piepared for a silicate filling 152 14 ILLUSTRATIONS FIG. I'^GE 86. A small Glass Three cavity, lingual approach, properly prepared for a silicate filling 152 87. A large Class Three cavity, labial approach, properly prepared for a silicate filling • 152 88. A large Class Three cavity, lingual approach, properly prepared for a silicate filling 15-j 89. A large Class Three cavity properly prepared for a silicate filling . . 153 90. Two extensive Class Three cavities properly prepared for a silicate filling 153 91. A small set of instruments for manipulating silicate 154 92. A suitable slab and spatula for working silicate 155 93. Proper position of the spatula on the slab w^hen manipulating silicate 156 94. Proper placing of the materials when manipulating silicate .... 156 95. Mixing the silicate filling 157 96. Mixing the silicate filling 157 97. Circular motion used in mixing the silicate filling 158 98. Scraping the material from the slab 159 99. The entire mix on the spatula . 160 100. Method of removing the mix from the spatula to the slab 160 101. Proper consistency of silicate 161 102. Shows mix of silicate too thin 161 103. A homemade mallet and point 162 104. Three cavities suitable for silicate fillings 163 105. Shows the results obtained after filling with silicate the cavities shown in Fig. 104 163 106. Combination gold inlay and silicate 171 107. Amalgam in position ready to receive a partial facing of silicate . . 172 108. Amalgam filling shown in Fig. 107 with the silicate facing built in . 172 109. An improper position with the operator doing his work at arm's length 235 110. Types of superior central incisors 236 111. Types of superior lateral incisors 237 112. Position for extracting superior incisors 238 113. Types of inferior central and lateral incisors 239 114. Position for extracting lower incisors 240 115. Types of superior cuspids 241 116. Position for extracting right superior cuspids 242 117. Position for extracting left superior cuspids 243 118. Mesial and distal application of forceps to a superior right cuspid when both adjacent teeth have been extracted 244 119. Types of inferior cuspids 246 120. Position for extracting inferior cuspids 247 121. Types of superior first and second bicuspids 248 122. Position for extracting right superior bicuspids 249 123. Position for extracting left superior bicuspids 250 124. Types of inferior first and second bicuspids 251 125. Position for extracting right inferior bicuspids 252 126. Position for extracting left inferior bicuspids 253 127. Types of superior first and second molars 254 128. Position for extracting first and second right superior molars . . . 255 129. Position for extracting first and second left superior molars . . . 256 130. Types of inferior first and second molars 257 131. Position for extracting first and second right inferior molars . . . 258 132. Position for extracting first and second left inferior molars .... 259 133. Types of superior third molars 260 ILLUSTRATIONS 15 FIG. PAGE 134. T^-pes of abnormal superior third molars 261 135. One of the many abnormal conditions found M-hen extracting upper second and third molars 262 136. Position for extracting riglit upper third molars 263 137. Position for extracting upper left third molars 264 138. T^-pes of inferior third molars 265 139. Elevator beaked forceps for extracting third molars 266 140. Position for extracting right inferior third molars 266 141. Position for extracting left inferior third molar 267 142. Complete set of deciduous teeth with the first permanent molar added . 270 143. Irregularity resulting from premature extraction of first deciduous molar 271 144. Horizontal injection 275 145. Perpendicular injection 276 146. Drawing representing the positions of needles in local anesthesia . , 277 147. First position in the mandibular injection 278 148. Second position in the mandibular injection 279 149. Third position for the mandibular injection 280 150. Fourth and last position for the mandibular injection 281 151. A very clear and easy case with the needle in the best position for the mandibular injection 282 152. A difficult case where the lingula is almost entirely wanting .... 283 153. Same mandible as shown in Fig. 153 with the needle passed to position suflEiciently high to be above the lingula 284 154. A mandible which belongs to a class on which it is very hard to give a mandibular injection 285 155. First and ideal position for giving the mental injection 286 156. Second position for giving the mental injection 287 157. Position of needle in giving the infra-orbital injection 289 158. Final position of the needle in giving the zygomatic injection . . . 291 159. Cavity preparation for a Class Two porcelain inlay 297 160. A Class Three cavity labial approach for porcelain inlay 298 161. A Class Three cavity labial approach for porcelain inlay 298 162. A Class Three cavity lingual approach for porcelain inlay 299 163. A Class Four cavity incisal approach for porcelain inlay 300 164. A Class Four, plan one, inciso-proximal api>roach for porcelain inlay 300 165. A Class Four, plan two, with doultle step for porcelain inlay .... 301 166. A Cla.ss Four, plan three, for porcelain inlay 302 167. Class Five cavities for porcelain inlay 303 168. Incisal cavity for porcelain inlay 304 169. A Class Six cavity using pin anchorage for porcelain inlay .... 305 170. Chisels for securing outline form 314 171. Spoons for removing softened dentine 315 172. Enamel hatchets for completing outline form and flattening dentine walls 316 173. Instruments for cutting point angles and sharpening base line angles . 317 174. Hatchets and hoes for cutting ascending line angles and completing retention form 318 175. Gingival marginal trimmers 319 176. Gold building pluggers 320 177. Dr. Rathbun 's dentech with teeth in position ready for practice work 321 178. A studr-nt who has kept his appointment with his patient, "Mr. Den- tech" 322 179. Forceps made after tlx; i)atterns of the author 323 180. Forceps made after the patterns of the author 324 0PEEAT1\ E 13ENT1STEY PART I CHAPTER I. INSTRUMENT NO:\IENCLATURE. A dental instrument is an appliance, or tool, by means of ^vhicli a dentist performs dental operations. It is quite essential that we loarn the names and uses of the instruments most in use if we are to understand the teachno' of operative procedures. Instruments are named according to the purpose for which they are intended, where and how used, by describing their working points and the shape of their shank. An order name describes that for which an instrument is used, as for example, excavator, clamps, mallet, pluggers, burnishers, etc. A sub-order name describes where or how an instrument of a given order is used and is made by inserting a prefix before the or- der name. P>xainples are hand pluggers, push or pull scalers, etc. A class name describes the working point of an instrument. Ex- amples are serrated plugger, ball burnisher, chisel, hatchet, etc. A sub-class name (k'sci-ibes the shai)e of the shank, and is made by prefixing this (lcs('i-ii)tion to the class or order name or to both combined. P^xamples are bayonet plugger, bin-angle chisel, mon- angle liatfhet excavator, etc. Rights and lefts are made as further divisions of many of the sulvclasscs of instruments and this division is especially advan- tageous ill the spoons, ])in-angle, conti-a-angle hatchets and mar- ginal trimmers, as it enables the user to do the Avork by a move- ment of the instrument from right to left, or left to right, respec- tively. An excavator is that order of hand instrument used in the re- iMoval of I00II1 substance preparatoi-y to the making of a filling. A chisel is thai class of exeavatoi- which lias Hu- cutting edge placed at right angles to the sliaft, is sharpciuMl b\- grinding on ]8 OPERATIVE DENTISTRY one side only and is used by a pushing force applied in the direc- tion of the long axis of the shaft. The chisel edg"e is made with a bevel at an angle calculated to plane and cleave a substance possessed of a grain, and is so tem- pered as to retain an edge when working on hard substances. The use of the chisel is, therefore, the cleaving and planing of enamel. The planing of dentine may be done with a chisel or with other instruments of a similar edge. Chisels are divided into sub-classes according to the shapes of their shanks, as straight, bin-angle, contra-angle, etc. A hoe is that class of excavator with the cutting edge at a right angle with the shaft, sharpened on the distal side only and is used by a pulling force applied parallel with the long axis of the shaft. Hoes are divided into sub-classes according to the shape of their shanks, as, mon-angie, bin-angle, contra-angle and triple-angle con- tra-angle. The hoe is used mostly for cutting dentine. A hatchet is that class of excavator with the line of the cutting edge laid in the plane parallel with the long axis of the shaft. Hatchets are divided into sub-classes the same as the hoes, ac- cording to the shape of their shank, as, mon-angle, bin-angle and triple-angle contra-angle. The hatchet form is indispensable for the construction of flat walls and internal surfaces, the straightening of lines and the sharpening of angles. A gingival marginal trimmer is a modified hatchet. A spoon is that class of excavator Avhich resembles in most re- spects the hatchet, other than the cutting edge. This is sharpened on one side only which is rounded like the convex side of the bowl of a spoon from which it derives its name. The cutting edge is rounded and sharpened to a thin edge. Spoons are always made rights and lefts. The use of a spoon is to remove foreign matter and softened dentine from the tooth cavity. The angles between the shank and the working part are desig- nated as mon-angle, bin-angles, and triple-angles, according to the number of angles used being one, two or three, respectively. The contra-angle is the placing of such angles in the shank of the instrument as to bring the cutting edge near the central line of the shaft which removes the tendency to tip or turn in the hand during use. Bin-angles and triple-angles are properly made only when con- tra-angled, provided the cutting edge is more than three millimeters from the central line of the shaft. INSTRUMENT NOMENCLATURE 19 Formula Names. Some instruments have the formula stamped on the handle in figures. There are generally three numbers given. The first is the Avidth of the hlade in tenths of a millimeter. The second is the length of the blade given in millimeters. The third is the angle of the l)hKle with its handle given in the hundredths of a circle. When a four-numl)er formula is given, as Avith gingival marginal trimmers, the second number in the name designates the angle of the cutting edge of the blade with shaft or handle. This is also given in the hundredths of a circle. A plugg'cr is an order of instrument foi- the packing of material in the making of a filling. Those for gold are serrated on the work- ing point in such shape as to result in a surface made up of prisms. These prisms should lie of exactly the same size on all the i^oints used in any individual filling when packing cohesive gold, as the interchange of points of different-sized serrations causes bridging. (See manipulation of cohesive gold. Chapter XX.) The dental engine is almost indispensable and when properly used is a blessing to our patients and a time-saver to the dentist. How- ever, it is all too frequently used, especially by students and young practitioners, to do things which can properly be done only with the hand instruments. The misuse of the dental engine has caused the public to regard it asthe climax of all pain-producing instru- ments in the dental office, Avhen in reality, if that Avhich should be done with the engine is jiroperly done, only a few seconds of pain is induced in the preparation of a very severe cavity. The engine bur is the woi-klng point of the engine and is made in many shapes and sizes. However, those which are round and in- verted cones, Avhose diameter is smaller than one millimetei", are most frequently indic;i1ed. The tendency of the beginner is to use too lai'ge burs. Hui's are primarily intended to cut dentine in out- lining cavity Avails, and for undermining enamel to facilitate the use of hand insti-iimeiils and 1licy should rarclx' conie in contact A\ ith the enamel. The most indispensable use of the engine is for Ihc i)olishiiig and grinding neeessary 1o the successful Ici-minal ion of many A^aried opei-alioiis, bolh in ;iii'l o\it of Ihc monlli. The sharpening of instruments is of Ihc nlmosl iiii])oi-1aMce and is by no means accomplished \\i1hoii1 skill. Xo heller can a dentist execute finished work Ihan c;iii ;i 1r;idcsiiiaM whose 1ools must be keen of edge if he is 1o produce 1li;i1 which is worlliy of his ci'afl. Again, dull inslrumenis cause an undue amouiil of pain at each at- 20 OPERATIVE DENTISTRY tempt to cut, whereas when sharp, the pain is less and the effort in cutting is materially lessened, resulting in a saving of pain to the patient and time and energy to the dentist. A hard, smooth Arkansas stone is the only suitable abrasive and should be well oiled and wiped with a cloth after each use. Care of Instruments. As the instruments are shipped to the den- tist they are usually made and sharpened especially for the use in- tended and care should be exercised in sharpening that the degree of the angle of the beveled edge is not changed. Tests for Sharpness. An instrument is tested for sharpness best by placing the edge with light pressure against the finger nail and attempting to move it across the surface at right angles to the edge. If it catches or clings to the nail it is ready for use. chaptp:r II. CAVITY NOMENCLATURE. A cavity nomenclature is necessary that we iiia\' iiii(lej'.staii(i one another in conversing about the formation of cavities, the descrip- tion of their several parts and the nietliods of procedure in the preparation of cavities for fillin«rs. Cavities derive their names from the surfaces of the teeth in ■which they occur. Thus occlusal cavity, buccal cavity, labial cav- ity, etc., are cavities occu)'rinj^ in the surfaces named. Fig. 1. — Defects in enamel. Proximal cavities are those occuj-i-inu- in llic proximal surfaces and are rlividr-d into two classes, namely, mesial and distal. A simple cavity is one which involves but one surface. A complex cavity is one which, either from decay or extension in preparation, involves more than one surface. Complex cavities are named by combininf? the names of the su)-- faces of tlif tooth involved, as mesio-occlusal, disto-occlusal, mesio- disto-occlusal, etc. An axial surface cavity is one which occurs in an axial surface. Cavities are divided as to their orij^in into two j^roups. Firsl. Pit and fissure cavities, which are those orif^inatiiif? in the miniilc faults in the enamel. CSee Fiji's. 1 and 2.) 21 22 OPERATIVE DENTISTRY Second. Smooth surface cavities, which are those occurring on sur- faces without defects in the enamel, but are habitually unclean; (See Figs. 3 and 4.) Cavities are divided according to similarity in line of treatment into six divisions. Class One. Those cavities beginning in structural defects. (Pits and fissures.) Class Two, Those cavities in the proximal surfaces of bicuspids and molars. Class Three. Those cavities in the proximal surfaces of incisors and cuspids not involving the incisal angle. Fig. 2. — Defects in enamel. Class Four. Those cavities in the proximal surfaces of incisors and cuspids which require the restoration of the incisal angle. Class Five. Those cavities in the gingival third of the labial, buccal and lingual surfaces not originating in faults in enamel. Class Six. Abraded surfaces. The outside walls of a cavity are those walls placed toAvard the outside surfaces of a tooth and take the names of the surfaces of the tooth toward which they are placed, as in an occlusal cavity the outside walls are buccal, distal, mesial and lingual, while the fifth or internal wall is the pulpal. The pulpal wall is that inside wall of a cavity which covers the pulp and is in a plane at right angles to the long axis of the tooth. CAVITY NOMENCLATURE 23 In case flie j^ulp is removed the piilpal wall becomes the sub- pulpal wall, in multi-rooted teeth. The axial wall is the inside wall of an axial surface cavity which covers the pulp and is in a plane parallel to the long axis of the tooth. Fig. 3. — Smooth surface decay. Fig. 4. — Smooth surfact; decay. In rase the pulp is removal in ;iii axial sui-face cavity the axi.al wall becomes an outside wall and takes llic name of llie surface of tlic tooth lowarfl Avhich il is placed. The gingival wall is the inside wall of an axial surface cavity OPERATIVE DENTISTRY placed toward, and running in the same plane as, the gingivae. Both ging-ival and sub-pulpal walls may be present in cases of pulp removal in mesio-occlusal, disto-occlusal, and mesio-disto-oc- Fig. 5. — Class One cavities filled. Fig. 6. — Class Two cavity filled. clusal cavities when each is on a different level and the individuality of each wall is retained. The inside walls of a cavity are those placed toward the pulp or root of a tooth. CAVITY NOMENCLATURE 25 The base of a cavity, or seat of a filling, is that portion of a cav- ity situated at right angles to the lines of force to Avhich it is most likely to be subjected. Generally speaking, this is the gingival or pulpal M-all, or both, where these Avails are present, as in a step cavitv. Fig. 7. — Class Three cavity filled. Fig. 8. — Class Four cavity filled. Fig. 9. — Class Five cavity filled. A line angle is formed where two walls of a cavity meet along a line and is named by joining the names of the Avails so meeting. There is hut one exception to this rule. That is whoi-e the labial and lingual walls of a proximal cavity in the incisoi-s and cuspids meet along a line. By applying the rule this Avould be called the 26 OPERATI\"E DENTISTRY labio-ling'ual angle, but for convenience this is named the ''incisal- line angle." A point angle is formed where three walls of a cavity meet at Fig. 10. — Bisected molar in which a mesial Class Two cavity has been cut and line angles indicated. The line angles are: a, Gingivo-buccal; b, Gingivo-lingual; c, Gingivo-axial; d, Axio-buccal; e, Axio-lingual; /, Axio-pulpal; g, Pulpo-buccal; h, Pulpo-lingual; i, Pulpo-distal; j, Disto-buccal; k, Disto-lingual. . Fig- 11-— Bisected molar m which a mesial Class Two cavity has been cut and point angles indicated. The point angles are: a, Gingivo-axio-buccal ; b, Gingivo-axio-Iingual; d, Pulpo-disto- lingual; e, Pulpo-disto-buccal. a point and is named by joining the names of the walls so meeting. Tliere is hut one exception to tJiis rule. The point of junction of CAVITY NOMENCLATURE 27 the axial, labial and lingual walls in proximal cavities in the six anterior teeth is, for convenience, named the "ineisal angle." A simple cavity has two sets of line angles. First, the internal line angles surrounding the internal wall, which is the axial wall in axial surface cavities, and the pulpal wall in occlusal cavities. The second set of external line angles is formed by the junc- tion of the outside walls with each other. The enamel margin is that point on the surface of the tooth where the cavitv begins in enamel. Fig. 12. — A, External enamel surface; B, Cavo-surfacc angle; C, Marginal bevel; D, Bevel angle; E, Enamel wall; F, Dento-enamel junction; G, Dentinal wall; H, Base line angles. The external enamel line is tlie entire outline of the cavity at its erianic] iiiarj^in. The cavo-surface angle is the angle foi-med by the junction of tlif \\;ill of the caNily with the external surface of tlie tooth. The base of the cavo-surface angle is the external enamel surface. The marginal bevel of a cavity is the dcdeclion of a cavity wall fr'om its eslahlislictl plane, near the exlenial cnaniel line. It is necessary that beveling be resorted to, in order to manage 28 OPERATIVE DENTISTRY the enamel margins, direct the external enamel line and control the degree of the cavo-surface angle, Avithont disturbing the gen- eral retentive form of the cavity. The bevel angle is the angle formed by the junction of the mar- ginal bevel with the remaining portion of the wall of which it is a. part. The base of the bevel angle is the remaining portion of the cavity wall. The bevel angle is covered when the filling is in position. Its distance from the enamel margin depends upon the filling material used, and the location in the cavity outline. To illustrate : With porcelain inlays and amalgam the bevel angle must be deeply bur- ied, resulting in a thicker edge of filling material. With cast gold inlays and platinum combination fillings the bevel angle should be near the surface, resulting in a short marginal bevel. The distance of the bevel angle from the cavo-surface angle must not affect the degree of the latter angle but determines only the length of the bevel and the thickness of the filling at its margin. The planes of a tooth are three in number ; horizontal plane, mesio- distal plane and bucco-lingual plane. The horizontal plane is at right angles to the long axis of the tooth. The mesio-distal plane passes through the tooth from mesial to distal parallel with the long axis. The bueco-lingnal plane passes through the tooth from buccal to lingual parallel with the long axis of the tooth. In the six anterior teeth this plane would be labio-lingual. CHAPTER III. CAVITY PREPARATION. ( GENERAL CONSIDERATIONS. ) Definition of Cavity Preparation. Cavity preparation is that term applied to those mechanical procedures upon a tooth, looking to the making of a filling, as well as those changes and extensions necessary to resist stress and prevent a recurrence of decay. Aff'ected Dentine is dentine which has been acted upon by the lactic acid in adxaiice of the micro-organisms of caries. Infected Dentine is dentine which has been penetrated by micro- organisms. Objects in Filling- Teeth. There are four general objects in vicAv in the filling of teeth : First. — To arrest the loss of tooth substance. Second. — To prevent recurrence of caries. Tliird. — To restore full tooth contour. Fourfli. — To improve the primary conditions as to the perform- ance of function and esthetic effects. A Completed Cavity should be a combination of flat walls com- ing together at definite angles, surrounded by an external line made up of the largest curves permissible. The Line Angles within a cavity, which are a necessary part of resistance and retention forms, should never be permitted to end in the external enamel line. Order of Procedure. To simplify the preparation of all cavities and to insure tiie (jbservance of certain fundamental principles it is Avell to follow a definite order of procedure. This will greatly facilitate the operations of the student and lead to the establish- ment of habits by the practitioner which Avill stand for thorough methods of execution. The following would seem to be the iiatnial ordci- : First. — Gain access. Second. — Outline form. Third. — Resistance form. Fo}irlk. — Retention form. Fifth. — r'onvcnicnce form. Sixth. — Removal of remaining decay. Seventh. — Finishing of enamel walls. Eighth. — Toilet of the cavity. 29 30 OPERATIVIS DENTISTRY Modification of Form is necessary in cavity preparation to meet the various properties of the different filling materials used. This is particularly true when considering the difference in edge strength and flow of metals and alloys. The character of the oral fluids, the evident care bestowed upon the teeth, condition of patient's health, age of patient and the life expectancy of the patient and of the individual teeth, will fre- quently require a modification of cavity formation to best resist the recurrence of decay and the dislodgement of the filling through stress. CHAPTER IV. GAINING ACCESS. Definition, (iaiiiing access is the term applied to those proced- ures necessary to make sufficient room for the i^roper introduction of the filling. Sufficient Access is Important, that ^ve may have the advantage of space to projDcrly handle the instruments and appliances used in the procedures of making a filling, that we may be al)le to intro- duce the filling into the cavity, that there may be complete contour restoration of tooth form and that the desired contact relation may be established to the adjacent tooth. Access to the Tooth is the first consideration and will involve the opening of the mouth to a sufficient degree to permit of the free use of the usual appliances. The i:)roximal spaces used for the adjustment of the dam should be examined to make sure that the rubber and ligatures Avill pass to the gingival line without injury. A sufficient number of teeth should be isolated, say four or five, to give a clear and unobstructive view of the cavity and surround- ing teeth. The operator must be able to bring the cavity into full view. Cases where there has been considerable decay sub-gingivally, and tumefaction of the gum septa has taken place, proper access Avill involve the packing of the cavity with a tampon of cotton Avhich has been dipped in chlora-percha, oi- a packing of gutta-percha, for a period of twenty-four or forty-eight hours, to crowd the en- croaching gum tissue from the cavity. A neglect of this considera- tion of access Avill often make proper management of the gingival wall and margin most difficult oi- imp()ssil)]e. Surgical Access may be practic(Ml on the cavity mai-giiis, A\heii all tooth structure thus removed w ill subsequently be replaced wilh filling material. It may be practiced on the gum septa when there has been excessive tumefaction in the pi-oximal space. Formerly this method Avas practiced wilh Class I^Mve cavities where the decay Avas to a marked cxlciit subgingival, and it A\as desired to make a cohesive gold filling. However, nnich of this f|uestional>le practice may now be avoided by the use of the gold inlay, made from the wax model, as llic pi-cscncc of tlic ovci'lying gum is no fonsidf'i-al)l(' liindranec. Access as Related to Restoration of Proximal Space. As tooth 31 32 OPERATIVE DENTISTRY substance is lost through decay in proximal cavities, there is in most cases a movement of the teeth to the proximal, encroaching on the normal space, robbing the gum of sufficient room for full festoon. It is wholly impossible in such cases for the operator in making a filling to restore tooth contour, or leave a normal amount of room for the rehabitation of the gum septa, without resorting to separation. The surfaces of a tooth which are covered with healthy gum tissue are practically immune from both prim.ary and secondary caries, and it is greatly to the advantage of a filling, the outline of which in the proximal gingival third, to be so protected. Good access should be gained by preliminary separation, so that when the completed filling with its full tooth-form restoration is in place, there is restored the normal proximal space for the habita- tion of the gum septa. A failure to regard this fact will result in a strangulated, diseased and dwarfed septa, inviting an accumula- tion of the enemy of tooth structure and an early loss of the filling through secondary caries. Restoration of Tooth Form is essential that the full function of the masticating organs may be established and maintained. It is also desirable for esthetic reasons, as the more nearly a dentist approaches complete tooth contour restoration, with all its details, the more pleasing is the appearance and the more artistic the result. Proper Contact Point is often impossible unless sufficient ac- cess has been secured through separation. This contact should be a point of contact, the embrasures widening therefrom in every direction. It should be in no sense a line of contact or a surface, no matter how small. It is advisable many times, in this respect, to improve on nature by slightly varying the surface of the filling from the original shape of the tooth, as often the predisposing cause of the primary decay has been defective contact. The Saving- of Tooth Substance is materially effected by access through preliminary separation, particularly in the placing of in- lays, as the more thoroughly this first step in procedure has been accomplished the less cutting will be required for convenience form, a point of no small importance. Methods of Separation. There are two classifications of separa- tion to gain access, preliminary, which is also slow separation, and immediate, which is rapid, both of which are a part of gaining ac- cess. The preliminary is a part of the first consideration, while im- GAINING ACCESS 33 mediate separation is brought to our attention during the introduc- tion of the filling. Preliminary Separation is best accomplished in proximal cavities in bicuspids and molars (Class Two) by packing into the partially excavated cavity an excess of gutta-percha base plate. A few days, or in some instances a few weeks, will suf^ce to accomplish the desired result, particularly if the patient uses that location in the mouth for daily mastication of solid food. In the proximal space in the six anteriors pi-eliminary separa- tion is best accomplished by the use of cotton tampons tightly packed ill the ca\it}- and ligatured securely to position. Immediate Separation is best accomplished with the mechanical separator, and should be used to gain additional access, not already secured by preliminary separation, or may be used primarily when only a small amount of additional space is desired. This instru- ment should be adjusted as soon as convenient after securing out- line form, and removed only Avhen the filling is finished. Avoid Gum Injuries in the use of elastic rubber. In the use of the methods given care should be used not to ci-owd the gum tissue as permanent injury may result. There are other materials used in slow separation, as linen tape, wooden wedges, etc., each with its merit and indicated use. Soreness Resulting from Tooth Separation should be treated as any case of acute pericementitis, by giving the tooth physiological rest, and the use of stimulating applications on the gum over the tooth's root. CHAPTER V. OUTLINE FORM. Definition. Outline form is that part of cavity preparation which determines the area of the tooth surface to be included within the external enamel line. Rule 1. Extend to Sound Enamel. All cavity margins should be extended until all indications of surface decay have been in- cluded. Rule 2. Obtain Full Length Rods. If necessary, further extend the outline until full-length enamel rods, supported by sound den- tine, have been reached. Rule 3. Self -Cleansing Margins. Extend the cavity outline un- til the surface of the filling can be so formed that the enamel mar- gin not protected by the gum will be mechanically cleansed by the excursions of food in mastication. Rule 4. In Relation to Developmental Grooves. A cavity out- line should not follow a developmental groove, or parallel it so closely as to leave a small strip of intervening enamel. The outline should cross the grooves as squarely as possible. Rule 5. Fissures and Sulcate Grooves. All fissures, sulcate grooves and angular developmental grooves encountered should be included within the cavity outline. This comes in for the greatest consideration when part of the outline is laid on an occlusal sur- face. Rule 6. Enamel Eminences. The outline should avoid extreme eminences of enamel and centers of primary development. Such locations are subject to the extremes of stress during mastication. When the eminence in question is the seat of primary calcification it will be found to be less perfect in formation than the portion midway from that point to the grooves. Rule 7. Avoid Angles in Outline. The outline should be made up of the greatest curves possible, avoiding all angles. Nearly flat axial surfaces should show nearly straight lines or the segments of very large circles, while on occlusal surfaces, which are made up of a succession of depressions and eminences, the outline should be a combination of smaller curves. Rule 8. Outline in the Embrasures. The outlines in the labial, buccal and lingual embrasures should be parallel to each other and 34 OUTLINE FORM 35 at right angles to the seat of the cavity, and pass under the free margin of the gum at a point in full view of the operator. Rule 9. Enamel Margins. The enamel margins should be planed smooth to a full cleavage of the enamel rods and then slightly beveled that the rods at the cavo-surface angle may be full-length Fig. 13. — Teclinic group illustrating outline form. Fig. 14. — Another view of cavities illustrated in Fig. 13. I'od.s, supported l)y shortened enamel i-ods which are ])r()tected by the o\'crlyiim- filling- iii;itei-i;il. Rule 10. Extension for Prevention. Wlicn ])(»ssihle, carry the cavity out line upon snmolli, uM<'lcan .surfaces, from an area of great liability to caries to an area of lesser liability 1o caries. This has reference to caries of enamel onlv and will ccmie into 36 OPERATIVE DENTISTRY consideration in cavity outline when the rules previously given i have not carried the outline to comparatively safe and immune ] localities. \ Fig. IS. — Fillings in place in cavities shown in Figs. 13 and 14. Fig. 16. — Another view of fillings shown in Fig. 15. Extension for prevention does not mean tJie consideration of re- sistance to stress. It bears no reference to decay of the dentine. It has no relation to the management of frail walls. OUTLINE FORM 37 Ifs }n(t.ri)uu)n tipiAicdiion is found in the management of small cavities where the ravages of decay have not yet carried the out- line of the cavity to areas not subject to pi'imary enamel dissolu- tion. Tlie abuses of extension ferr prevention result in much unneces- sary loss of tooth substance, while its sane and legitimate use is one of the most important factors in tooth salvage. Dangers of Increased Cavity Outline. The danger of secondary caries increases in each mouth proportionately as the aggregate length of cavity outline is increased. To IJlusfrafi. If the total length of cavity outline of all fillings in a mouth is doubled by the increase in numl^er of fillings the lia])ility to secondary caries is doubled, all else being equal. For that reason each individual cavity should have its outline as short as permissible. The laying of cavity outline in locations not suscepti]:)le to pri- mary caries "will materially decrease the liability to recurrent de- cay, even though the aggregate cavity outline in the mouth is thereby greatly lengtiiened. An aggregate cavity outline of two feet is preferable to a total of one foot, provided the additional 1-^ngth has been caused to extend to locations not lia])le to caries. CHAPTER VI. EESISTANCE FORM. Definition. — Extension for resistance is a term applied to that procedure whicli has for its sole object the carrying of the cavity outline from localities subjected to great stress, to localities not frequently subjected to the crushing strain. This is often mistaken for extension for prevention, whereas it has reference only to re- sistance to stress. A proper application of this procedure will involve a careful study of occlusion and articulation in each individual case. Resistance form involves a consideration of the management of weakened enamel walls and a stud}^ of the flow and edge strength of the filling material used with a view of so shaping the cavity as to minimize the effects of the crushing strain. Its importance is in direct proportion to the exposure of the fill- ing in occlusion and articulation, and the strength of the closure of the jaAvs. The force to provide for is from one to two hundred pounds and in some cases even more, particularly in mid- jaw locations. Weakened enamel walls are those which through decay, or un- necessary cutting, have been robbed of much of their supporting dentine. All such unsupported enamel should be cut away with a chisel, particularly if by any chance the wall of enamel under con- sideration Avill receive much stress in the process of mastication, or the introduction of the filling. Stress from within should be avoided by not allowing such weak- ened walls to remain and form any part of the retention of the filling. Weakened walls are sometimes allowed to remain, or a portion of them, when they can be so protected by a layer of rigid filling material as to prevent all stress, but this is permissible only when their presence will screen unsightly metal fillings and when the kind of filling used can be introduced Avithout injury to the walls. Before applying the rubber dam each case should be inspected for the surface contact in occlusion and articulation and then the margin so laid as to occupy the least exposed position. Many times all stress cannot be avoided, but the amount of stress a margin is liable to receive should have due consideration and good judgment exercised in the placing of the margin. 38 RESISTANCE FORM 39 Resistance Form as Applied to Filling Material. We are forced to eoii.sider the properties of the filling material to be used in each individual cavity. In preparing the cavity we consider the resist- ing power of the enamel margin we are a])le to obtain. We also take into account the resistance of the filling material used, to the crushing strain, as this property varies greatly. Amalgam, even under the most favorable manipulation, is subject to flow and more or less spheroiding, which often results in a slight exposure of the cavo-surface angle. Again, amalgam is not ductal, hence these edges of this filling are easily fractured at the margins under stress. This liability to fracture at the margin is also true of our cement and silicate fillings and great care should be exercised in placing the margins of these fillings. Cohesive gold, especially Avhen alloyed with platinum, is our best filling material to resist the crushing strain at the margins, and when the edges are not too thin, the repeated blows from the opposing teeth only tend to drive this material in closer adaptation to the margins. When using the gold inlay, it is quite necessary to exercise great care at the mar- gins to resist the crushing strain, not of the gold, but of the en- amel margin and the intervening cement, for unless the gold in- lay fits better than the average gold inlay, there is a line of ce- ment which is subsequently dissolved. This leaves the last rods at the cavo-surface angle unprotected, and very liable to injury. It therefore follows that the amount of marginal extension for resistance form is less for cohesive gold and gold inlays than other fillings. The greater the edge strength of the filling matei-ial, the more protection it gives the cavity margins. Yet resistance form should receive careful consideration with fillings of maximum edge strength. CHAPTER VII. RETENTION FORM. Definition. Retention form is that part of the procedure in cav- ity preparation which deals with the provisions for preventing the filing from being displaced by the tipping strain. Force which results in tipping the filling bodily from the cavity, is one of the greatest enemies to permanency in tooth filling, second only to re- current caries. Partially Provided For in R-esistance Form. Retention form is partially provided for in the previous step of resistance form, but it is further necessary that provision be made to resist the force of mastication in order to prevent the filling as a whole from being moved from its seat. Maximum Retention Form is required in cavities in the proximal surfaces as the missing proximal wall renders these fillings particu- larly exposed to injury by the tipping force, during the movements of the mandible. Flat seats for fillings are imperative in retention form. Seats should be cut in a plane at right angles to the stress of mastica- tion, which is usually at right angles to the long axis of the tooth. The Step as a Part of Retention Form. The addition of the step in cavities of Class Two and Class Four is for the purpose of giving added retention form. By this procedure in proximal cavities in bicuspids and molars, the stress upon buccal and lingual walls of the cavity proper is transferred to those portions of the same walls which are a part of the step, a location much better situated to withstand the tipping strain. In cavities of Class Four, the addi- tion of the step on the incisal or lingual, or both, will give added retention form, avoiding heavy cutting at the angle, which weakens the remaining tooth substance at the angle, to say nothing of the dangers of crossing the retractive tract of the pulp in this location. Maximum Retention Form is not required when making simple cavities, as they are protected from the dangers of lateral strain by the presence of surrounding external walls. This will be found to be the case in cavities of Classes One, Three and Five when oc- clusion is normal. While in cavities of Classes Two, Four and Six, much additional cutting is sometimes necessary to give ample re- tention form. Acute Angles Required. Much of the retention form required 40 RETEXTIOX FORM 41 is gained by laj-ing the external surrounding Avails at definite angles to the seat of the filliiiu'. Little Retention in Enamel. It should be remembered in this step of cavity preparation that there is very little resistance to force in a filling wherein retention form is provided for in enamel walls. The enamel should be removed to a depth sufficient to get anchorage in angles laid in dentine. A good idea of the amount of retention form possessed ])y any completed cavity may be gained if one will for the time being imagine that all enamel has been re- moved from the tooth. The remaining cavity Avill still have nearly the original amount of retention form. We rely upon the presence of enamel in liable areas for resistance to recurrent caries and upon .sound dentine for retention form. CHAPTER VIII. CONVENIENCE FORM. Definition. Convenience form is that part of cavity preparation wherein is made those additional changes necessary for the proper placing of a filling. Sparingly Used. As these additional cavity changes and their accompanying loss of tooth substance are made entirely for the convenience of the operator they should be resorted to only in cases of necessity. Maximum Convenience Form. The cutting necessary for con- venience form reaches the maximum ; first, with inlay fillings, as the previously prepared filling is moved to position en masse ; sec- ond, in the making of a cohesive gold filling, as it is of value to apply force as near as possible at a right angle to the anchorage of the first portion of gold, and at an angle of 45 degrees to the wall against which the gold is being condensed ; third, in cavities in the posterior teeth, and in distal cavities as compared with mesial ; fourth, more is required for proximal fillings not previously sepa- rated. Minimum Convenience Form is required; first, in using plastic fillings ; second, in anterior oral locations ; third, where the teeth have had ample separation before the making of a proximal filling. The Abuse of Convenience Form is of harm to the teeth and has reached its height in a desire to inlay every case possible. When excessive cutting for convenience form is necessary to the making of an inlay, it would often be better to avoid the unnecessary loss of tooth substance b^v^ changing the character of the filling. Suitable Instruments for various locations in the mouth, par- ticularly with the posterior distal cavities, will do much to minimize convenience form. Previous Separation is the most potent factor of all in lessening the amount of cutting for convenience form, the same having been considered fully in access form, and should be resorted to in cav- ities of Classes Two and Three if for no other reason. Starting Points for the making of a cohesive gold filling are a part of convenience form and are made by making one of the point angles more acute than is required for general retention. This is made in the point angle farthest from the hand when the 42 COXVENIEXCE FORM 43 same is in position with the plugger point resting in the cavity. This will be fonnd to be the point angle farthest from vision and .most difficult to fill, and from the latter fact should be the first filled. CHAPTER IX. REMOVAL OF REMAINING CARIOUS DENTINE.— FINISHING ENAMEL WALLS.— TOILET OF THE CAVITY. Eemoval of Remaining' Carious Dentine. Definition. This order is the secondary consideration of af- fected dentine. In the smaller cavities the previous steps in cav- ity preparation will have removed all affected dentine and this step has little consequence. However, it is well to have this step come to the mind even in these cases so that the minute corners and ob- scure localities are not allowed to pass imperfectly prepared. In Large Decays the pulp is often in question. The dentine has been softened to a near approach to the pulp. If all of this be re- moved early in the procedure, the pulp Avill be exposed to the dam- aging effects of air drafts from the chip blower, or possibly low temperatures in the operating room. Pulps thus exposed not in- frequently take on the initial stages of destructive diseases from which they never recover, resulting in much pain to the patient and chagrin to the operator. The foregoing is particularly true when one is making a filling for each of two large proximal cavities. Two Large Proximal Cavities. It is often desirable to prepare both cavities at the same sitting, particularly when filling with amalgam. With the cavity first prepared, there might be a long exposure of the pulp to a lower than body temperature, if the overlying de- cayed dentine is removed at the time the major jDortion is ex- cavated. Technic. The remaining decay in this step of procedure should be removed with broad spoon excavators, when working on axial or pulpal walls. In small cavities where there is no danger of pulp exposure the instruments should be small hatchets, with which the dento-enamel junction should be examined around the entire cav- ity. In case a softened area is found and removed the overlying enamel should be chiseled aAvay, thus restoring the correct out- line. Where Exposed Pulp is expected or pulp treatment is intended, the decay is removed just following outline form. 44 TOILET OF THE CAVITY 45 Finishing' Enamel Walls. Definition. The last cutting done in the preparation of a cavity is the finishing of enamel walls. This should ahvays be done with the rubber dam in place or at least sufficient means taken to pre- A'ent the margins from again becoming moist. No Moisture should be Permitted to come in contact with any portion of the cavity surface, after final instrumentation, and if by accident any portion should become wet that portion should be thoroughly dried and freshened ])y cutting away the surface, and the filling immediately placed. The Cavo-surface Angle of the cavity in every part of the cavity outline should receive special attention at this step in cavity prep- aration. The Plane of the Enamel \\all should be so laid Avith reference to the cleavage of the enamel that these will be cut more from the outer than the inner ends of the rods, resulting in the last rod at the cavo-surface angle being a full length rod, supported by short- ened rods. The shortened enamel rods are covered with the fill- ing material \\lien the completed filling is in position. This is accomplished by a slight planing motion parallel to the external enamel line, using a keen-edged chisel or enamel hatchet. The gingival margin trimmers are especially adapted for this pur- pose Avheu finishing the margins in the gingival third. The Marginal Bevel should be laid in a plane at an angle of from six to ten centi'igrade degrees from the plane of the enamel cleav- age. The Depth of the Marginal Bevel sliould generally not include more thaji one-fourth of the enamel wall, but when making a fill- ing of inferior edge strength, as amalgam, porcelain, cement, etc., it becomes necessary to bury the bevel angle more deeply. Locations subject to great stress also require the placing of the bevel angle more deeply, even carrying it beyond the enamel- and laying it in the dentine. Toilet of the Cavity. Definition. The toilet of the cavity is Hie final stcj) in the prep- aration of the cavity and consists of freeing the cavity of all loose particles of tooth substance whicli arc not fiiinlx attached to the <'avity walls. This is best accomplished l)\- a blast of air from llic clii]) blowei-, follr)wed hy a tliof(»n- will be found to haA^e progressed more toward one embrasure than the otliei- Avhich necessitates ad- ditional cntting foi- pi-evention, in the direction of the embrasure least apj)roached by decay. This should be done to the fnlfillment of the I'ule for "extension fo?- prevention." Gingival Outline. The gingival onllinc in these eases Avill gen- erally be under the free margin of the gnm. At this stage it should be planed Avith the enamel hatchets until the overhanging enamel 65 66 OPERATIVE DENTISTRY is broken away to give access form for the free passage of the dam and ligature, which should now be placed and the cavity super- ficially sterilized. Occlusal Outline. When the cavity has been rendered dry the occlusal outline should be proceeded with. This is carried out as previously given in the forming of the step portion, and the full satisfaction of the rules given in Outline Form, Chapter V. Removal of Remaining Decay. This is an instance where the sixth step in cavity preparation comes in third and should now be cautiously proceeded with. Technic. Large spoons should be used. The softened and dis- colored dentine should be lifted from its position with as little pres- sure pulp-wise as possible. If exposure exists upon its removal, pulp treatment for devitalization and removal is the immediate pro- cedure. If exposure does not exist and the operator has reason to believe that that organ is healthy the pulpal and axial walls should be lightly scraped with large spoon excavators, the walls disinfected with the favorite drug, then dried, phenolized and dried again, the latter precaution to prevent thermal shock to the pulp during the remaining portion of cavity preparation, the impera- tive necessity for which is shown when pain is induced by a blast of air from the chip blower. Resistance and Retention Forms. When the central portion of the decay is found to be deep and no exposure exists, the pulpal and axial walls should be left in their central portions much as de- cay has left them, no attempt being made to flatten these walls on a plane of their greatest depth as pulp exposure may result. The line angles surrounding these two walls should be established on higher levels. The Gingival Wall should be made flat in every direction. This is accomplished by lowering the point angles root-wise to the level of the central portion. Convenience Form. Every part of the cavity should be exam- ined to see that it is accessible to direct force in the packing of the filling and a convenience point cut in each of the gingivo-axio- lingual and gingivo-axio-buccal point angles. Pulp Protection. The cavity should be flooded with an efficient non-irritating disinfectant, dried, phenolized and again dried. If the pulp is in danger it should be protected as described in Chap- ter XXXIV. LARGE PROXIMAL CAVITIES ENDANGERING PULP 67 Finish of Enamel Walls. The enamel Avails should now be inspected, corrected for com- plete cleavage and the proper cavo-surface angle established, iis- Fig. 27. — Large Class Two cavities in non-vital teeth restoring part of the occlusal surface for the protection of weakened walls. A B Fig. 28. — Class Two filled. Cavities shown in Fig. 27. ing for this a keen-edged cliiscl and a light hand with a planing motion parallel witii the external enamel line. For Toilet of the Cavity use a few blasts of air from the chip C8 OPERATR^ DENTISTRY blower, followed with a thorough brushing with a ball of cotton and more air blasts. The filling should be immediately placed. Large Proximal Cavities in Non- Vital Teeth. In the management of this class of cavities, cutting for resistance Fig. 29. — Mesio-occluso-distal (M.O.D.) cavities in molar ani bicuspid, vital teeth. Note that the occlusal portion of the cavities does not show any retentive form. It is not necessary to undercut these walls as there is ample retention in other parts of the cavity. A B Fig. 30. — Mesio-occluso-distal fillings. Cavities shown in Fig. 29. to stress reaches the maximum and outline is many times materially extended for this purpose alone. Outline Form, With Molars. All decay and softened dentine is removed. Often this will leave standing an entire cusp of un- LARGE PROXIMAL CAVITIES EXDAXGERIXG PULP 69 supported enamel and possibly both proximal cusps are thus un- supported. Ill such cases a thin-edged carborundum wheel is placed on the occlusal and this surface ground away for one or two milli- meters, extending as far toward the central axial line to just be- -^^^^^^H PH '^;i^H ^ [ M i^^ 1 ^l^HHi^l Fig. 31. — {A) First superior molar, non-vital, restoring the lingual cusps. (B) Second superior bicuspid, non-vital, restoring the entire occlusal surface. A B Fi^. 32. — Class Two filled. Cavities shown in Fig. 31. yoiid the (Miccal or lingual groove, or bolh when l)()tli cusps are to be removed. This grinding process is carried to a greater depth in the region of the groove, resulting in a stej) which gives the fill- ing an occlusal surface seating. 70 OPERATIVE DENTISTRY With Bicuspids this buccal or lingual outline is carried past th.e crest of the cusp involved and partially down the opposite slope. This procedure results in disarticulating the frail enamel w^all and so placing the metal that it will receive the force of mastication. In Mesio-Disto-Occlusal Cavities in both bicuspids and molars, which are vital, and when using cohesive gold as a filling, the occlusal outline should include all of the middle third bucco-lingually. It should be made sufficiently deep to remove all of the enamel in the central fissure. For cohesive gold the buccal and lingual walls should be parallel and without retention as the retentive form should all be placed low in the gingival angles of both mesial and distal cavities. In the use of amalgam the outline should be farther extended buc- co-lingually, to include about one-half of each of the buccal and lin- gual thirds. Thus two-thirds of the occlusal surface bucco-lingually will be filling. This occlusal portion should be without retentive form with the buccal and lingual walls meeting the pulpal wall at angles slightly obtuse. This is the minimum amount of extension for favorable vital cases. In Cases of Extreme Frailty the entire occlusal surface of molars and bicuspids should be replaced with filling of at least one milli- meter in thickness. With upper molars and bicuspids, when non- vital and very frail mesio-occluso-distal cavities, the lingual cusps should be removed for one or two millimeters and replaced with filling material. Retention Form is Completed by squaring up the side walls and sub-pulpal wall, making a box shape of the pulp chamber, with fairly definite point angles. Convenience Form. No convenience form is necessary in this class of cavities, except for inlay fillings, which will be considered later. Neglected Access Form. In cases where large proximal cavities are of long standing and there has been much tipping to the prox- imal of one or both teeth, preliminary separation for good access is essential. Without this preliminary step complete contour res- toration and proper contact is impossible. This is particularly true when the cavity is in the mesial of the first molar. Many times the second bicuspid will seem to have been engulfed within the molar cavity. In cases where preliminary separation for obvious reasons is impossible, the evil may be partly overcome by the free cutting away of both buccal and lingual walls until the filling may LARGE PROXIMAL CAVITIES ENDANGERING PULP 71 be built ill with a proximal surface slightly convex to the prox- inial. However, this is but a makeshift of a filling and the result- ing proximal space will ahvays be defective. Toilet of the Cavity. In large decays, particularly if the pulp has been removed, there is more or less danger in leaving coatings of various materials clinging to the walls. Care should be taken that the walls are scrupulously clean. It is an advantage if the cavity be scrubbed with solvents for the suspected coatings. The cavity should then be dried, the enamel walls planed and the cav- ity freed of all debris. Over-desiccation. Particular care should be had not to use ex- cess desiccation in pulpless teeth as this will render them brittle and easy of fracture when put to use. CHAPTER XIV. MANAGEMENT OF PROXIMAL CAVITIES IN INCISORS AND CUSPIDS NOT INVOLVING THE ANGLE. (CLASS THREE.) Definition. Class Three cavities are those in the proximal of incisors and cuspids where it is not necessary to restore the ineisal angle. The angle may be allowed to remain when the enamel at the angle is supported by sound dentine to an extent which will give it sufficient resistance to prevent fracture under stress of mastication. General Form of Class Three. Cavities in incisor proximal sur- faces differ from all others in that they are in the surface of teeth of a triangular form and the cavities of necessity must be of this form, rather than the typical box shape in the other classes of cavities. Location of Primary Decay. The location of primary decay, as with all contact decay, is just gingivally from contact point. This will result, as a rule, in the seat of initial decay being about mid- way from the ineisal edge to the gingival outline. As the plates of enamel, both labial and lingual, are quite heavy and usually removed from direct stress, there will generally be considerable loss of dentine while the enamel walls are yet intact. The decay may be apparently small, yet reflected light by the use of mouth mirror will show a discoloration of a well defined area. The curved tine of an explorer may or may not enter from either the labial or lingual embrasure. Opening the Cavity. Bathe the surfaces of all the anterior teeth in that jaw with water to free them of micro-organisms and gummy material, particularly the gingival border, and apply the mechan- ical separator. Gaining Access. With a small straight chisel of about one milli- meter in width cut away the enamel edge, throwing the chips into the cavity. Adequate finger rest must be secured before applying the chisel and only small portions of enamel engaged at each ap- plication, as a failure in either respect may result in checking the j3namel to a greater extent than desired. When sufficient entrance has been made to the cavity to admit the instrument, the remain- ing enamel margins may be planed from this direction until a liga- 72 PROXIMAL CAVITIES IN INCISORS AND CUSPIDS 73 tiire Avill pass from the incisal to the gingival line. Where time Avill permit the ease should be packed for preliminary separation as described in Chapter IV. If immediate separation and filling is to be practiced the rubber dam should be adjusted and the me- chanical separator placed and tightened to a snug pressure. The separator should be tightened from time to time until the required separation is obtained. The approxi)nate space required is from one-half to one millimeter Avhere only one cavity exists in the prox- imal, and a full millimeter in cases where two cavities exist. Outline Form. As these cavities are located in the most exposed portion of the mouth esthetic reasons demand as little cutting as possible consistent with the demands for permanency. However, ABC Fig. 33. — Class Three cavities filled so that the entire cavity outline, excepting that jior- tion covered by gum tissue, is in full view of the operator. The gingival portion of (B) has been cut sufficiently low to be covered by gum tissue. it is a good I'ule, in outlining cavities of Class Three, to extend in all directions until when the filling is completed, the entire cavity outline not covered with gum tissue, is in full view of the operator. (Fig. 33.) As stated before, excessive cutting to obtain this con- dition may be obviated by proper separation. The Gingival Outline should be carried midway l)etween con- tact and gum line, and farther extended to go under the gum Avhen it approaches to within one millimeter of the gum. Great care should be exercised to scpiai-o out both labial and lingual axio- gingival angles, carrying tlicui suffi('ientl\' into these embi-asuT'es 74 OPERATIVE DENTISTRY that the cavity margins may be in full view as they pass under the gum. The Incisal Outline should be carried incisally until the margin of the filling will be permanently in view, with a space sufficient to admit of the free use of the tooth brush on the margin. This would, in many instances, carry the margin beyond the incisal edge and make a Class Four cavity and is only avoided by separa- tion and filling of the cavity to a slightly excess contour. The Labial Outline should be carried into the labial embrasure until the margins are in full view. The enamel should be split away until full length rods are obtained. On account of the ex- posed location of these cavities the esthetic reasons demand as lit- tle cutting labially as possible. As this margin is practically re- moved from the stress of occlusion it is not essential that the enamel be supported by dentine in every instance. However, care should be taken that the rods are full length and that all rods are re- moved where there has been a backward decay as shown by a whitened powder-like condition at their dentinal ends. Additional Extension for esthetic reasons is sometimes required in th^ labial embrasure. This is more often true in the mesial cavi- ties wherein the teeth are angular in form and present surfaces that are quite flat, resulting in a very square or prominent mesio- labial angle. In such cases the outline should be carried over the angle and into the labial surface, that the metal may be brought into the light, otherwise the completed filling will have the appear- ance of a decay or dark spot on the tooth. The Lingual Outline must be carried into the lingual embrasure sufficiently to be brought into full view in all cases. In the case of teeth of rounded form this will not always in- clude the proximal marginal ridge. In teeth of a squared form and prominent lingual ridges the marginal ridges should be in- cluded and the outline carried along the axial slope of the ridge. The fact that many cases show a lingual articulation and occlusion on the lingual marginal ridges of upper incisors, will bring de- mands for including within the cavity the major portion of these ridges, unless supported by a good bulk of sound dentine. The failure to recognize this fact on the part of many operators is re- sponsible for the loss of a large per cent of this class of fillings. Resistance Form. No special resistance form other than that just given is required in this class of cavities. Retention Form. When this order in the preparation has been reached attention should be directed to the incisal angle, particu- PROXIMAL CAVITIES IN INCISORS AND CUSPIDS 75 larly in the larger eavities, as eases Avill be met in which it will be found necessary to remove the incisal angle to secure proper ^'retention form." This looking to the incisal first will decide this point early in the procedure. The Incisal Line Angle should meet the axial wall at least at a right angle. In eases where this line angle is short, as found in shallow cavities, the incisal line angle should meet the axial wall at a slightly acute angle. It is not necessary to make a convenience angle at the incisal point angle. (Fig. 34.) The bevel angle on the gingival wall becomes the fulcrum. It is only necessary that the distance from this point to the incisal point angle be greater than that from the same point on the gin- Fig. 34. — Drawing to illustrate the retention at the incisal angle of Class Three cavity. In shallow cavities with a short incisal line angle as d — b, the angle at b should be acute. In deeper cavities and longer incisal line angles as the one shown at d — c, the incisal point angle is efficient if it is a right angle and may even be obtuse. In the illustration shown the filling would pivot to exit at a. Dotted lines a — b and a — c are the same length hence the point angles of the two fillings would describe an arc of the same circle in tipping to exit. gival wall to the most external portion of the incisal line angle. The more shallow the cavity in Class Three the more acute must be the incisal point angle. Other Point Angles. The gingivo-axio-labial and the gingivo- axio-lingual p(nnt angles are now carried into the dentine at the expense of both axial and external Avails, care being given not to groove the gingival wall. Line Angles. Line angles are made with small hatchets and hoes of suitable sizes, say, one-third to one-half millimeter in width, Avith edges that are keen and whose corners are well defined, not having been rounded through careless shai-pening or wear. 76 OPERATIVE DENTISTRY The Axio-Labial Line Angle is chased and sharpened for its entire length, making it particularly definite as it approaches each of the point angles. The Axio-Lingual Line Angle is made definite for one millimeter in each direction from its two point angles, omitting the central por- Fig. 35. — Class Three cavities prepared for cohesive gold. While the cavity in the cuspid (A) restores the mesial angle the shape of these cavities and the rules governing their man- agement places them in Class Three. ABC Fig. 36. — Class Three filled. Cavities shovi^n in Fig. 35. tion, as this precaution will give added resistance form to the lingual wall. The sharpening of these line angles is best accomplished by engaging the instrument in the dentine the desired distance from the point angle and cutting to the angle. The Gingivo-Axial Line Angle should be well defined to make the PROXIMAL CAVITIES IX INCISORS AND CUSPIDS 77 gingival wall meet the axial at a definite angle, but should in no way be a ditch or groove. The Gingivo-Labial and Gingivo-Lingiial Line Angles should be cut aAvay from their point angles out to and end at the dento-enamel junction. As the general form of the cavity is that of a triangle these angles will always be acute. Gingival Wall. The gingival wall should be flat in every direc- tion. Axial Wall. The axial wall should be left as decay has left it in the central portion and all additional cutting should tend to make it take on the form, in miniature, of the surface of the tooth in which the decay has originated. A disregard of this rule will endanger the pulp, Avhereas if the axial M-all is left as convex as possible the pulp has all ]')ossible protection. Labial and Lingual Walls. These walls should be, as far as pos- sible, of the same thickness for their entire length, which will re- sult in their inner surfaces being of the same contour as the ex- ternal surface of the tooth. Convenience Form. Ta\'o convenience points are advisable in this class of cavities, cut in each of the gingivo-axio-labial and the gin- givo-axio-lingual angles. The filling should l)e begun in the latter angle. Removal of Remaining Decay. At this point inspect the dento- enaiiiel junction foi- softened dentine. Also the entire axial wall should be scraped with large spoons for the i-emoval of the last of the softened dentine, the cavity disinfected, di'ied, phenolized and again dried. Pul]) ])i-otoctor should be applied when indicated. Finish of Enamel Walls. The enamel Avails should be planed to full cleavage, with suitable insti-uments of chisel edges, not forget- ting the incisal and gingival inclination of the rods of these loca- tions. Bevel the cavo-surface angle, give the cavity its toilet and iiiiiiK'diatcly ])laf'c the filling. In Non- Vital Cases. When the axial wall has been lost l^y reason of pulp removal the entire pulp chamber should be filled Avith ce- ment of a A'ery light yelloAv color or even a Avhite cement may be used. In extremely frail teeth this may be only pai'tially filled and the remaining portion used for retention. CHAPTER XV. MANAGEMENT OF PROXIMAL CAVITIES IN INCISORS IN- VOLVING THE ANGLE. (CLASS FOUR.) Definition. Cavities of Class Four are those in which the incisal angle has either been lost or can not be safely retained. The deci- sion as to its restoration is of most vital importance. To cnt the angle from nearly every incisor which has a proximal decay is little short of malpractice, while at the same time to attempt to save those not wholly and adequately supported by dentine is to invite many disastrous failures. Conditions Demanding Frequent Angle Restoration. First. When contact is in the incisal third. In such cases a very small decay will involve all of the dentine toward the incisal angle. Second. Incisors which have long flat proximal surfaces. Such teeth will show a line of decay extending gingivo-incisally and may entirely weaken the incisal angle before the pulp is in danger. Third. The pulp may be involved and its removal materially lessens the resistance of supporting dentine at the angle. FourtJi. The angle under consideration may be so located that it is frequently required to stand great stress in service. This is a point which must not be overlooked as an angle which stands well exposed must bear much greater and more often repeated force than an angle which does not occlude or can not be brought into articula- tion. Difference Between Mesial and Distal Surfaces. The above four conditions will be more frequently met with in mesial surfaces, hence the mesial angles are in greater danger and more often re- quire restoration. Plans of Angle Restoration. There are four general plans of re- storing the incisal angle which are worthy of consideration. Many plans have been advanced from time to time, but the four given below seem to have remained in favor. Retention Form in Class Four Fillings. With each of the plans presented and generally practiced the effort is made to remove or nullify the principle of the lever. With proximal fillings wherein the force of mastication is brought in direct contact with the filling the principles of the lever must be reckoned with. The force of mastication is the power, the filling the lever, the anchorage in the point angles the load and the point on 78 PROXIMAL CAVITIES IN INCISORS INVOLVING ANGLE 79 which the filling would most likely pivot to exit the fulcrum. By a study of the case we find we must deal with the force of levers of both the first and second class. In Fig. 37 we have an illustration of a Class Four, plan one filling wherein the principles of a lever of the second class are fully opera- tive. The heavy long lines a-h represent the full length of the lever. The short heavy lines a-c represent that part of the lever which is the Avorking arm, as the load is at c. That we may study the amount of anchorage to be provided for at the incisal angle, (c), we will ignore the assistance of the two gingival point angles and for that reason they have not been shown in the drawing. We here Fig. 37. — Drawings to illustrate the principle of the lever in the dislodgement of fillings of the fourth class, plan one. have a lever of the second class with the fulcrum at a, the load at c and the force at h. In order that we may not inject into the problem at this time the principle of the bent lever we will consider that by the lateral move- ment of the mandible the force is applied at right angles to the "lever-arm." In diagram A, Fig. 37, the working arm is one-half of the lever which is of the second class. We then have the follow- ing with X representing the load, or unknown quantity: 100 lbs. : X : : 2 : 4 = ^°° _ = 200 lbs. = x. 2x It would therefore follow that an incisal point angle placed mid- 80 OPERATIVE DENTISTRY way betAveen the gingival wall and the incisal surface of the filling would be required to stand a strain just double the force at the in- cisal, or place of impact. In diagram B, Fig. 37, the incisal point angle is placed three-fourths of the way from the gingival to the in- cisal and we then have : 400 100 lbs. : X : : 3 : 4 = — g— — ISSl/g lbs. — x. This shows a strain on the incisal point angle of one hundred and thirty-three pounds. It will therefore be seen that the incisal point Fig. 38. — Drawing.s to illustrate the principle of the lever in the dislodgement of fillings of the fourth class, plans one and two. angle should be laid as close to the incisal edge of the tooth as the strength of the dentine protecting that angle will permit as it fol- lows that: "Tlie fartlier tlie incisal angle is from tlie force of masti- cation the greater will he tlie strain on hotJi dentine and filling at tJiis angle." With Fig. 38 Ave Avill consider the principles in a little more com- plicated form. Let a represent the fulcrum, h and c the loads and d the point of the application of the force. The radii of the arcs of the circles represent a fcAV of the directions from which force may be received by the filling. With the light lines the force Avould be PROXIMAL CAVITIES IX IXCISORS IXVOLVIXG AXGLE 81 absorbed by the walls of the cavity. Force from the direction of the dark lines -wonld pnt into operation the principles of the lever. In diagram A, Fig 38, the filling would operate as a lever of the second class upon the load at c, as described in Fig. 37. With the gingival point angles at h the filling Avould operate as a lever of the first class over the same fulcrum (a), provided the gingival outline or fulcrum has been laid higher than the point angle and therefore nearer the point of the application of the force. In case the gingival margin has 1)een laid lower than the point angle or farther from the point of impact than the fulcrum we have a lever of the second class which when figured out will draw an im- mense load as shown in the explanation of Fig. 37. In case the gingival poiut angles are cut more root-wise than the gingival margin and we have a lever of the first class we must con- sider the principles of the l^ent lever. AVhen the direction of the force (or of the resistance) is not at right angles to the arm or the lever on Avhich it acts, the "le^er-arm" is the length of the per- pendicular from the fulcrum to the line of the dii'ection of the force (or the resistance). AVe must therefore conclude: First, that gingival point angles should be placed so as to extend more root-wise than the height of the gingival line at the proximal (that part of the gingival wall which is nearest the incisal is regarded as the highest point). Second, the farther the gingiA'al wall with all its parts is from the incisal the greater will ])e the length of the power arm with each individual blow. Third, the nearer the gingival wall is to the incisal the less the number of directions from Avhich force may be received which will act upon the filling as a lever. In order that we may eliminate the principles of the levers, the step cavity, in classes two and four, has been devised as shown in diagram B, Fig. 38. It will l>e seen by the radii of the three arcs drawn that the increase of the surface of the filling exposed to force does not increase the dangers of the lever as the area of the seat of the filling has also been increased Avhich Avill absorb the force beneath the increased surface. Again, so long as the incisal angle in the step (at c) holds and the filling material remains rigid the lever principle has been eliiiiinalc*! as regards all other anchorage of the filling. Direction of the Incisal Angle. I'ig. :!!) is a diawing to illnstrate the difference in the directions Die ])oint anyles take in tii)ping to exit with various filling. Lot the ])('i-])('ii(licnhii- shaft i'e]iresent the varying length of (.'lass I-'oui- fillings and the hoi-izontal bars the 82 OPERATIVE DENTISTRY varying lengths of the step hi plan two of this class. The dotted lines are the radii of the various circles the arcs of which the point angles would describe in moving to exit, pivoting on the gingival margin. The length of the step portion relative to the height of the filling determines the direction the incisal point angle must take to exit. With a short proximal portion and a comparatively long step portion, the first movement of the point angle is almost per- pendicular. See fillings in Fig. 39 {a, x, li; also g, f, n). Fig. 39._Drawing to illustrate the difference in the directions the point angle fillings take in tipping to exit with various fillings. Note the difference in the direction the point angle would take to exit with an increased length of filling inciso-gingivally. Also see li, X, a, and then li, x, h, and on down until it is It, x, g. It vnil be seen that there is a gradation toward the horizontal movement of the incisal point angle to exit. Again note the change of direc- tion to exit of the incisal point angles in g, a, i, and then g, h, j, then g, c, h, and on down to g, f, n. We see in this series that there is a gradation toward the perpendicular movement of the incisal point PROXIMAL CAVITIES IX INCISORS INVOLVING ANGLE 83 angle to exit. In the first instance "\ve lengthened the axial wall, us- ing the same length of step. In the second instance we shortened the axial wall and at the same time lengthened the step and the change is more rapid. It would seem then that the direction to be given the incisal point angle is determined by the degree of the circle in which lays a line drawn from the deepest portion of the incisal point angle to the fulcrum. (See dotted lines Fig. 39.) The nearer this line in a given case approaches the perpendicular to the axial part of the filling the more essential is it that the point angle be cut in the same plane as the axial wall. Also the nearer this line approaches ninety degrees from the perpendicular the more es- sential is it that the incisal point angle be cut at forty-five degrees to the perpendicular of the axial wall. Bv a study of Fig. 40 it will be seen that the incisal angle of Fig. 40. — Drawings to illustrate the importance which should be given to the proper plac- ing of the incisal point angle in fillings of Class Four, plan two, with particular reference to the plane in which wall b — c should be cut. A would be effective while B would offer no resistance to exit with a filling pivoting at a. By materially shortening the axial walls of both, the point angle of B becomes effective and that of A ineffective. As shown in the drawings in A the dentine included in h, c, d is the rotontif)n i)roduced by having dotted line a, h longer than line a, c. Ill B these lines are the same length, hence no retention. The filling.'- l)ff()iiif's a Ifxcr to lift the gingival point angles. The Gingival Angles. h\ the study of the gingival angle reten- tion, wf will eliminate the incisal angle and consider that it has been improperly laid or has been Aveakened and llio lexer foreo has been transmitted to the gingival angles. 84 OPERATIVE DENTISTRY In Fig. 41, a is the fulcrum and h the extreme point of the angle. Dotted lines a-h are the radii of the circles the arcs of which the point angle fillings would describe in going to exit. The two gingival point angles should be of different depths so that they Avill describe the arcs of different circles in being drawn to exit. It is most cojivenient to make the gingivo-axio-lingual the deeper. A B Fig. 41. — A study in the proper placing and deptli of the gingival angles. .../ Fig. 42. — A study of the planes in which the gingival angles should be laid. It is also essential that the two gingival point angles be so laid that the circles, the arcs of which the point angle fillings describe in passing to exit, stand in different planes as illustrated in Fig. 42. Failure to observe the last two principles given removes retention form as regards the gingival angles. PROXIMAL CAVITIES IX INCISORS INVOLVING ANGLE 85 First Plan of Angle Restoration. (Class Four.) The first plan of anchorage is made by undercutting the incisal edge. This plan is indicated in teeth of rather thick incisal edge that are rather short and stocky as they have a greater body of den- line near the angles upon Avhich to depend. Fig. 43. — Cavity of Class Four, plan one, for cohesive gold. Fig. 44. — Class Four, plan one, cavity filled. Labial and lingual views. Cavity shown in Fig. 43. As a rule the horns of tlic i)ulp in siicli teeth arc Avell retracted, at lejist in adult mouths, and there is less danger of pulp exposure as compared Avith the teeth of thin edges and angular outline. If this plan has been decided upon, Iho cavily sh(mld be cut well to the 86 OPERATIVE DENTISTRY gingival, particularly at the gingival angles, in some cases to the ex- tent that the gingival wall is made convex to the incisal. The Gingival Point Angles should be deep and well defined at the expense of both gingival and axial walls. This is particularly true of the gingivo-lingual angles, to protect against the torsion strain. To Assist the Incisal Angle. To resist the tipping strain both the labial and lingual Avails should be slightly grooved along the axio- labial and axio-lingual line angles much in the same way as with large Class Three cavities. The Labial Outline should so proceed that the completed filling will be of about equal width for its entire length except that as it approaches the incisal edge it should be slightly curved to the axial. Fig. 45. — Shows incisal outline in Class Four, plan one, fillings with direct occlusion. A Rule for Labial Outlines. All cavity outlines in incisal angle restorations should curve to the axial as they approach the incisal edge. The nearer this outline approaches the central axial line of the tooth the greater should be the curve. When the central axial line is reached by a cavity outline, the same should then be extended to involve the opposite angle. There are exceptions to the above rule but maximum resistance to stress is only thereby obtained. The Necessity for Curving to the Axial. When approaching the incisal edge curve to the axial that the last rods at the cavo-surface angle may be adequately supported. A large per cent of fillings where this precaution has been neglected fail, showing a primary fault due to the breaking away of the enamel at this point. PROXIMAL CAVITIES IN INCISORS INVOLVING ANGLE 87 The Incisal Outline as it crosses the incisal edge of thick teeth shoukl have in its center a curve toward the axial caused by a slight groove in the center of the dentine. This groove which ends at this point in the cavity outline should originate at the external end of the incisal line angle. If there is sufficient dentine, and there gen- erally will be in the class of cases calling for this plan of restora- tion, this groove is of best service if it be a flattened groove and made Avith a small hoe or hatchet. (Fig. 45.) The LingTial Outline should be the same as for large Class Three except in the incisal third Avhen it should curve to the axial even more rapidly than the labial outline and for a longer distance, re- sulting in cutting away more enamel from the lingual than is re- moved by the labial outline. This is made necessary from the fact that all stress is from the lingual. With Lower Incisors the reverse is true and it is necessary to re- move slightly more of the labial enamel in angle restoration, a fact Avhicli materially mars these teeth from an esthetic point of view. Fortunately Ave have comj^aratiA-ely fcAv angles to restore on loAver incisors, but Avhen they are presented the fact must be borne in mind that they receive the major portion of stress from the inciso- labial direction. Second Plan of Angle Restoration. (Class Four.) The second plan of restoration is indicated in teeth that are of medium thickness, particularly if they are of angular build or have a direct contact on the incisal edge either in occlusion or articula- tion, and consists in the additon to plan one of Avhat is termed the incisal step. The cavity proper is prepared the same as has been outlined in plan one up to the forming of the step. The Incisal Edge is cut aAvay Avith a narroAv-edged carborundum stone, the cutting being extended toAvard the opposite angle a dis- tance equal to the Avidth of the cavity proper. The incisal outline should avoid both the centers of primary calcification and the point of coalescence, two Aveak places in enamel construction. The cut- ting should be more at the expense of the lingual side of the tooth by onc-h;i]f to one millimeter. The Depth of This Step, inciso-gingivally, Avill depend upon the thickness of the cutting edge, and the probable stress it Avill receive. The thinner the edge and the greater the probable stress, the deep- er must be the step. The majority of cases Avill shoAV not to exceed one milliiiieter of gold on the labial in the step portion. Technic of Cutting. A small i-onnd bur is then used to cut a 88 OPERATIVE DENTISTRY groove in this newly formed pulpal wall, near the clento-enamel junction next to the lingual plate of enamel. The lingual enamel is then removed with a chisel thus carrying that portion of the pulpal wall to a loAver level. This process is continued until it is at least Fig. 46. — Cavity of Class Four, plan two, for cohesive gold. Fig. 47. — Class Four, plan two, filled. Labial and lingual views. A very popular method. Cavity shown in Fig. 46. one-half millimeter to one millimeter lower than the labial portion of the pulpal wall. This leaves the major portion of the dentine sup- porting the labial plate of enamel. The Point Angle in the Step Portion should be deepened and made PROXIMAL CAVITIES IN INCISORS INVOLVING ANGLE 89 acute largely at the expense of the piilpal Avail. This will place it in just the right position to resist stress from the probable source and prevent tipping. (See Fig. 37.) This Second Plan is Particularly Indicated in eases of mueli wear Fig. 48. — Cavity of Class Four, plan tliree. for cohesive gold. A B Fig. 49.— Class Four, plan three, filled. Laliial and lingual views. Cavity shown in Fig. 48. on the incisal, due to wliat is called "end-to-end" bite. However, in such cases all of the exposed dentine on the incisal edge should be included in the .step and it is not necessary to remove much of either of the lalnal ov liiiuua! ])lMtes of enamel. In such cases the 90 OPERATIVE DENTISTRY step portion should be retentive throughout as it is liable to be worn away by subsequent wear, growing thinner from year to year, hence the necessity of retentive form from cavo-surface angle to the base line angles. Third Plan of Angle Restoration. (Class Four.) This plan is the addition to plan one of the lingual step. It is particularly indicated in cases of long incisors which are quite thin labio-lingually and subjected to a long sweep of the lower incisors in the movements of articulation, or what is spoken of as the ''scis- sors bite." Also Indicated in cases where the axial wall extends out to the enamel edge on the lingual thus removing the lingual wall. The Labial Outline is the same as with the first plan of restora- tion. The step is formed on the lingual b;^ cutting away the enamel from the lingual surface of the tooth toward the central axial line for a distance of from one to two millimeters at the incisal edge. As the gingival is approached the cutting is narrowed to a point where the marginal ridge may be crossed at right angles to meet the gingival portion of the outline. This will form a V-shaped axial Avail of dentine facing the lingual. There should be cut a flat- floored groove in this dentine parallel with the remaining enamel Avail ending in the gingiA^o-axio -lingual angle AA^hich should be an acute conA'enience angle. The plan giA^es great resistance to stress from lingual pressure. Fourth Plan of Angle Restoration. (Class Four.) This plan consists of resorting to all of the features of resistance and retention embodied in plans tAVo and three by combining both the lingual and incisal steps. Each of these has been fully de- scribed and the method of cutting both steps to the same should not prove hard to accomplish. By this plan the maximum resistance and retention forms are se- cured Avith the minimum loss of dentine. It must be remembered that resistance to stress is good in proportion to the amount of se- curing dentine retained, hence it should be sparingly cut away. The remoA'al of enamel to lay bare dentine Avherein to lay anchor- age is only harmful from the esthetic standpoint and is of little loss when taken aAvay from a surface not in vicAV, as is the case Avhen Ave cut aAvay a portion of the lingual plate. Cavities in the Distal of Superior Cuspids. On account of the peculiar articulation of the lingual surface of superior cuspids this PROXIMAL CAVITIES IN INCISORS INVOLVING ANGLE 91 cavity has been left for separate consideration. The plan given is a modification of plan three, using a lingual step not unlike the oc- clusal step in a class two cavity. Fig. 50. — Cavity of Class Four, plan four, for cohesive gold showing maximum anchorage with a minimum loss of dentine. The use of this plan is advised when the lingual stress is great. A B Fig. 51. — Class Four, jilan four, filled. I.aliial and lingual views. Cavity shown in Fig. 50. Access is an easy uiattei- as the decay is in the most prominent part of the distal surface and ;i little work with the chisel gives ac- cess to the cavitv. 92 OPERATIVE DENTISTRY Outline Form. In outlining the cavity proper most of that vv^hich has been said about plan one should be followed here. As to the lingual outline and that of the step particular attention must be paid to so placing the margins as to remove them as much as possible from the stress of articulation. The Step. The lingual step is added to this cavity as it ma- terially assists in retention, resistance and convenience forms. In the laying of the walls of the step portion the particulars are carried out much as though the lingual surface of the cuspid were an occlusal surface, as next to an occlusal surface it receives the greatest stress in articulation. Axial Walls. It will be seen that this cavity has two axial walls. Fig. 52. Fig. 5; Fig. 52. — Cavity of Class Four, modified plan three, for cohesive gold in the distal of the superior cuspid. This plan is sometimes tised to advantage in the incisors when the tooth is short and stocky. In such cases the lingual step is made to include the lingual pit. Fig. 53. — Class Four, modified plan three, filled. Cavity shown in Fig. 52. The one in cavity proper is the axial, while that in the step is termed the lingual axial wall. The Lingnal Axial Wall should be placed on a plane parallel with the lingual surface of the tooth. Its surrounding line angles should be laid just below the dento-enamel junction. Convenience Form in this cavity is pretty well secured by the ad- dition of this lingual step, as the filling is then easily built in from the lingual direction. Both gingival point angles in the cavity proper should be made convenience angles as well as the axio- gingivo-mesial point angle in the step portion. CHAPTER XVI. MANAGEMENT OF CAVITIES IX THE GINGIVAL THIKD. (CLASS FIVE.) Gingival Third Cavities Differ from all other cavities in the teeth ill that they uriinal I'idge. When this is reached on the buccal or lingual the outline should include the marginal ridge and at least one millimeter of the axial Avail be involved. All deep grooves should be included. The curves should be as generous as possible. Resistance Form. The same rules apply as to other fillings. W'lieii iiiucii of the supporting dentine has been removed through decay or cavity preparation from either the buccal or lingual walls, that portion Avithiii the cavity should be covei-ed with a thin layer of black wax. which prevents the wax pattern fi-om coming in con- 102 OPERATIVE DENTISTRY tact with these walls. The cast mlay will then not touch these walls during the process of introduction, which will often save a fracture of these walls, due to stress from within when driving the inlay home to a seat. The Major Portion of Retention Form comes in for considera- tion after the inlay has been cast and fitted and just before ce- menting to place. However, a flat seat and nearly parallel walls Fig. 57. — Class One inlay in position showing gold wire cast in the filling, which was put into the wax pattern to support the long buccal arin. Cavity shown at (S) Fig. 56. to this seat with fairly definite angles, is necessary to guard against the tipping strain and produce proper retention form. Preparation of Cavities of Class Two. Large proximal cavities in molars and biscupids are successfully handled with this method of filling. Access. Preliminary separation is of the greatest service here and should be general practice as much cutting for convenience form is avoided, and better contact secured. Complete Preliminary Separation very materially facilitates the removal of the wax pattern as the operator does not have to be as careful about having his wax pattern tight against the surface of the adjacent tooth. In addition to the preliminary separation before making the pattern, it is to the advantage of the operator CAVITY PREPARATION FOR GOLD INLAYS 103 to pack the case for additional separation during the interim be- tween making the pattern and setting the inlay. Outline Form. The outline for inlay filling is much the same as for other methods. Care should be taken that the buccal and lingual walls are parallel, particularly the enamel portion of these walls, as the wax pattern must move directly to the occlusal sur- face in exit. It is equally essential in inlays that angles and sharp turns in outline be avoided, particularly as they will not take in the wax pattern and any defect in the casting exaggerates the misfit. Resistance Form. Flat gingival and pulpal walls are demanded in class two. Weakened buccal and lingual cusps should be re- moved and replaced with the filling material. » Fig. 58. — Cavities of Class Two for gold inlays. Cavity side of inlays shown. Black wax has been used in the molar to temporarily remove the retention produced by decay. Retention Form is best secured for vital cases by making four convenience angles in each case similar in size to those for co- hesive gold. However, these convenience angles should be laid d(nvu in the gingival and ])ulj)al walls and cut entirely at the ex- pense of these walls rather than at the expense of the tooth substance in the region of the ascending line angles. To describe the process more accurately take a round bur, about number one-half or iniiii^ ber two, sink it into the gingivo-axio-buccal and gingivo-axio-lin- gual j)oint angles about the depth of the bur. To this point the procedure is the same as though we were going to make a con- venience angle for cohesive gold. Instead of sinking the bur later- ally into the ascendinjj line angle and drawing it occlusally, as 104 OPERATIVE DENTISTRY with cohesive gold, we draw it toward the mesio-distal plane along the gingivo-axial line angle, allowing it to fade out, after going once or twice the width of the bur, taking the tooth substance from the gingival wall. Treat both lower point angles in this man- ner. In the step portion of the cavity follow the same procedure in the two point angles, cutting all tooth substances at the expense of the pulpal wall. This results in giving the cavity draw to the occlusal and giving your inlay four lugs, which key the filling to a seating, particularly in the region of the gingivo-buccal and gin- givo-lingual point angles. It also results in placing your retention form high in vital cases and near the force of mastication, and in a part of a vital tooth which is well suited to stand the tipping strain. (Fig. 58.) In Non-Vital Cases the retention form should be placed low in the tooth. In fact the major portion of it should be below the gin- gival wall, and this is more frequently secured by the use of the pin inlay. When the pin is not used, the pulp chamber is so shaped that the wax pattern Avill show a lug, which can be used for the major portion of the retention. Finishing of Enamel Walls. This part of the cavity prepara- tion should be attended to with all of the care and detail that is required when making a cohesive gold filling. In addition there- to, after the planing has been done with a chisel, x>articularly on the buccal and lingual outline, these margins should be pol- ished with a very fine grit disk. This facilitates the travel of the wax on these two surfaces when going to exit. A chisel fin- ish on these surfaces, results in a pattern that under the micro- scope shows little fine-projections, which have gone into the rough- ened surface. In drawing the pattern these little projections have been bent and point gingivally. This results in an imperfect cast- ing along these surfaces and interferes with the fit. Whereas if the surfaces have been polished, a polished wax pattern results and the completed inlay more nearly fits the margins. When the cavity on account of decay is naturally retentive or has undercuts these are temporarily filled and overcome by cov- ering the retentive portion of the cavity with some substance, as temporary stopping or wax of a different color than that used in making the pattern. Preparation of Cavities of Class Three. The gold inlay is seldom indicated, in cavities of Class Three. CAVITY PREPARATION FOR GOLD INLAYS 105 All exception may be made in those Avhieh are lary:e and have thrcniuh decay lost their entire lingnal wall. Access. It is of a necessity from the lingual as Class Three cavities receive their stress from that direction. The Outline is the same as though a cohesive filling "were to be made. Care should be taken that the labial level is laid on the same plane as the travel of the wax pattern to exit, else this por- tion of the model will l)e distorted in removal. The Gingival Wall Should Meet the axial Avail at an acute an- Fig. 59. — Cavity of Class Three for gold inlay, lingual approach. Cavity side of inlay shown. gle and the cavity should liave a 1 axio-incisal. • The labio-axial line than the outline of the cavity wh gual surface. This will result in lingual. As the labial wall, which care should be taken that it is w else the seating of the iiilav will Fig. 60. — Inlay shown in in place. Fig. 59 partly ine angle which might be termed angle should be slightly shorter ere the axial Avail meets the lin- allowing the pattern exit to the is the seat of the cavity, is frail, ell supported by sound dentine, cause fracture of this Avail. Preparation of Cavities of Class Four. The u.se of the inlay sliould be largely restricted to non-vital ca.ses and a ])iii in the pulp canal used for the major portion of leteiilion. If the Inlay is used in Class Four plans one and Ihree, the case 106 OPERATIVE DENTISTRY sliould always be devitalized. In vital cases the inlay may be used to advantage in plans two and four. Resistance Form. In this part of cavity procedure the same care should be exercised as when using the cohesive gold filling. Fig. 61. — Cavity of Class Four, plan one, for gold inlay. Cavity side of inlay shown. Fig. 62. — Class Four, plan one, inlay in position. Cavity shown in Fig. 61. This is particularly true at the incisal edge, where the beveling to the axial should be quite generous to protect against breaking down of this margin due to the fact that stress comes at right angles to the long axis of the enamel rods. CAVITY PREPARATION FOR GOLD INLAYS 107 Retention Form. This step in cavity procedure will vary ac- cording to Avhich plan of Class Four is used. In plan one, which as before stated should be used only in non-vital cases, a pin should be placed in the pulp canal and depended upon almost en- Fig. 63. — Cavity of Class Four, plan two, for gold inlay. Cavity side of inlay shown. wax has been used to temporarily remove undercuts caused by decay. Black Fig. 64. — Class Four, plan two, gold inlay in position. Cavity shown in Fig. 63. tirely for tlie rctenti('lding cold again rctui'us. 124 OPERATI\'E DENTISTEY If tlie Surface of Foil Becomes contaminated with, a non-evapor- able substance the injury is permanent. To Protect tlie Surface of Gold. Place in the drawer where the gold is kept a small pledget of cotton or spunk saturated with am- monia. Ammonium salts will form on the surface of the gold, which are easily volatilized b^' heat, leaving the gold clean. Before anneal- ing such gold will be found thoroughly non-cohesive. This meth- od of treating the gold to the fumes of ammonia will obviate the necessity of keeping more than one kind of gold on hand, as all will be non-cohesive till annealed and can be used in either form. Annealing" Gold is for the sole purpose of cleaning the surface of the gold by volatilizing any film that may have collected. The Degree of Heat is about 1100°F., or just below red heat. In the daylight this color is not apparent, but on a dark day the dull red color should show. The gold is not materially injured if carried to the full red of 1200 or 1300 degrees, but in no case should the melting point be reached, as it destroys the possibility of adaptation to the walls of the cavity, or the surface of the gold already in place. Methods of Annealing. The electric annealer is by far the most satisfactory means, as it is possible to always obtain the same de- gree of heat for a continued period. Tlie Next Best Means is to place the gold on a tray above a flame, thus separating the flame from the gold, preventing contamination of the gold with carbon, and various gases which are frequently met with in combustion. Gold SJiould Not Be Annealed hy Passing It TJirougli tlie Open Flame of either gas or alcohol, holding the gold either on a plug- ger point or the foil carriers. This is quite a common practice, which should be discontinued. In the first place, heating the gold with the open flame frequently contaminates its surface, to the injury of its welding properties. Also that portion of the gold next to the carrier is not sufficient- ly heated and remains non-cohesive, a fact which is shown by the subsequent pitting of the surface of the filling during service by the flecking off of these non-cohesive particles. Specific Gravity. The specific gravity of the cast gold inlay is about 19, varying the fraction of a point. It is possible to condense a cohesive gold filling when confined between the Avails of elastic dentine so as to obtain a slightly greater specific gravity than the cast inlay. However, this degree COHESIVE GOLD IN THE MAKING OF A FILLING 125 of solidity is not possible of attainment unless the gold is eon- fined and the Avedoing- principle is taken advantage of. Cohesion of Gold. The surfaces of pure gold Avheii absolutely clean readily cohere. This cohesion is brought about by the fric- tion of the surfaces of the gold when in absolute adaptation. The degree of cohesion is in proportion to the friction. The friction is in proportion to the load, the extent of the surfaces in opposi- tion and the speed of the travel of the surfaces one upon the other. Hence, the greater the load, the smaller the surface, and the more rapid the movement of one surface upon the other the greater the cohesion. Polished surfaces of gold must be brought into co- adaptation in order to get cohesion. The smaller the surfaces and the thinner the sheets, the less load and speed will be required. The Serrated Plugger Points are used in condensing cohesive gold for the following reasons: That these polished surfaces may be kept small and uniform ; that great pressure (load) may be eas- ily exerted on the polished planes previously left in the surface of the gold by the wedge-shaped serrations. The mallet is applied to give the additional factor in friction (speed) as the fresh gold is moved over these small polished surfaces. The above conditions are obtained with the least exertion on the part of the operator and annoyance to the patient by the serrated plugger point, which is made of a collection of pyramids which act as so many wedges and exert great lateral force (load) upon the polished sides of their previous impression. That gold coheres to polished surfaces can be easily demonstrated by taking any cohesive gold filling and burnishing its surface to a glossy finish. Pellets of gold from the annealer will readily cohere and the filling may be continued to full contour by applying a steel burnisher with heavy pressure drawn over the surface of the fresh gold. This process proves that burnished gold coheres, but it is slow and la])orious and ol^jeetion- able to the patient, heuce the serrated ])luggei' point which ac- complishes the same result, the friction of polished surfaces of gold under pressure, causing their welding. Bridging is the tei-m applied to that faulty manipulation Avhich results in air s])aces within the body of the filling, caused by the gold failing to reach the b(>ttom of the indentations of the serrated plugger point. The Cause may ])e insufficient pi-essure being given the plugger point, lln- ii-old thereby sto])j)iiig short of the bottom of the serra- tions, or it may be caused by too mucli liglit niallc) iiig, going over tlie r ])oint still niaiiilained at an angle (»f 12 degrees 1o the plane of the axial Avail. The Layers of Gold in Class l-'onr should i-cceive some atlcnlion and what is said in this (•oniic<-1ion is Irnc of all conloui- resffira- 136 OPERATIVE DENTISTRY tions subject to great stress. Not a little trouble has been experi- enced in the breaking of such fillings through given lines of fracture. These should be noticed and the layers of gold leaf so placed as to cross these lines. The tensile strength of the sheets of gold is greater than the usual cohesion obtained giving a filling more strength across the laminations than parallel with them. Class Five Cavities in the Gingival Third. Class Five cavities in the gingival third need no special mention as they are built under the rules already outlined in Class One. The gold is usually started in the disto-axio-gingival angle and carried along the gingivo-axial line angle to the other gingival point angle. The gingival wall will be the first wall to be completely cov- ered. The mallet force should not be directed at a right angle until that wall has been covered with a considerable layer of gold. Class Six. Abraded Surfaces. These cavities are built the same as large flat cavities in the same surface, the principles of which have been given. CHAPTER XXII. FINISHING GOLD FILLINGS. Secondary Consideration. When a gold filling has been built to its full size, the entire surface should be gone over with a plugger point of moderate size. The point should be stepped so as to cover every accessible part of the filling. A light mallet with a hard surface should be used. A two ounce steel-faced mallet is preferred. Burnishing-. All accessible parts of the surface should then be thoroughly burnished with a steel burnisher. The egg-shaped bur- nisher is of most universal use as it will reach most positions. If the filling is a proximal filling of Classes Two, Three or Four, a thin steel hand matrix should ])e forced between the filling and the proximating tooth to burnish the contact point and to better con- dense and harden the filling at this place. This is done by swinging the handle back and forth describing the part of a circle, till there is moi'e or less freedom of movement of the burnisher. Following This Secondary Condensation the process of smoothing the surface with abrasives begins. The first efforts should be to find cavity outline, second, to correct contour in localities where an ex- cess ha>s been built and third, to polish the contact point. This is best accomplished by the use of small carljorundum stones on occlusal surfaces, disks on buccal, lingual and labial contours, and narrow coarse strips in the proximal, gingivally from contact point assisted by the use of file cut burnishers. Attention should first be given to all parts of the filling except contact point which, in all proximal fillings should be the last place to receive finish. The Use of the Saw in the proximal space in the finishing of the filling cannot be ttjo .strongly condemned. In the first place no cut- ting in.strument, or coarse abradent, as strips or disks, should Ijc made to pass contact point except whei'c there has been ample })re- liminary separation and the return of the teeth to position is relied upon to close the resultant space. Again there is no excuse for build- ing an excess of contour sufficient to engage the bite of a saw blade. The Excess at the Gingival should be sliglit, and it, with the ex- cess fullness ill 11h' ciiihrasurcs, should be filed away with the files, or whittled off with the burnishing knife, the edge of which should be keen. The files should ])e cai'ried through the eiii1)t'asures as fai" to- y.'.T 138 OPERATIVE DENTISTRY ward the center of the filling as possible and drawn directly outward and over the edge of the filling out to the external enamel surface. The Finishing" Knife should be engaged into the substance of the gold and drawn from the gum and at the same time outward, tak- ing off only a small portion of gold at each cut. Coarse Abrasives, as carborundum stones and coarse disks and strips, should be abandoned as soon as a near approach to the cavo- surface angle is reached, and the files, plug-finishing burs, and knife edged instruments resorted to, to bring into view the exact cavity outline, after which the finer strips and disks should be employed to bring gold and tooth substance to an exact level at the cavo-sarface angle for the entire cavity outline. Finishing Strips in the Proximal. To reduce the quantity of gold from contact point to the gingival, a coarse finishing strip sufficient- ly narrow to reach from the gingival outline to near the contact point only, is of advantage. This strip is introduced by sharpening one end and passing through the embrasure below contact point and then drawn back and forth till the desired surface is secured. Fine narrow linen strips are then used in the same way to give a final finish to this place of difficult access. When the Entire Cavity Outline Has Been Exposed and the sur- face otherAvise made ready for the final finish the separator should be tightened another degree, when it will be found that a broad fine linen strip will easily pass contact point. This should be given three or four sweeps with this broad strip not too tightly drawn, when the contact point should be considered finished. The separator should be gradually loosened and removed, the rub- ber dam removed and the filling tested for occlusion and articula- tion and properly shaped. The filling should then receive a thorough finish, with wood points, leather wheels and tooth cleaning brushes, carrying first pumice, then whiting, till the surface of the filling is as smooth as the external enamel surface. CHAPTER XXIII. MANIPULATION OF AMALGA:\I IN THE MAKING OF A FILLING. Definition. Anuilgam is a coiuposition of inercury witli one or more other metals. It is most commonly combined with two or more other metals which have been previously alloyed and finely divided either as shavings or filings to facilitate union wdth the mercury. History. Amalgam for the filling of teeth was int?-odnced into Fi-ance about the year 182G by M. Teveau, who called it "silver paste." This was composed of silver and mercury alone, and must have given very unsatisfactory results as compared with those se- cured in the use of our modern alloys. Reception. The use of amalgam A\as given a most uu^velc()lne reception l^y the profession at large, while the converts of the "new process" were equally emphatic in their praise of the ucav filling which "would certainly cheapen dentistry, and harm the profession." But time has proved amalgam to be a blessing to the poorer classes in that it brings dentistry within the reach of all purses and has thereby proved of advantage to the dental profession by broadening its field of usefulness. "While amalgam has many faults and should generally be avoided when finance will permit, the fact still remains that moi'c teeth have been saved through its use than with any other filling material. However the ])ercentage of salvage is greater Avith gold, which foi'ces amalsiam to second place. The Properties of Amalgam wliidi rcndei' it of value as a filling material ai'c: I'^ii'st. its ])lasticity eliminating access form in cavity preparation, making ])ossil)le the 1)uilding up of lost contours in inac- cessible places in the mouth, where convenience and access foi-ms are hard to secui'e. sufficient foi* the manipulation of gold either co- hesive or as an inlay; second, its ])i'operty of being but slightly af- fected by the oral lluids, and tlic fact that it is faii-ly stable as to bulk and shaj)e; and last, but not ](>ast in the minds of many pa- tients, we ai-e soi-ry to say, is its cheapness, as most dentists see fit to l>uild filliny:s of amalgam for a much smallei" fee than gold. The Objections to Amalgam arc: lis tendency to discolor both as t(j its (xposcd surface and Ihc Iccth with which it has l)een filled due to slight leakage Avith old fillings; its comj)arative]y large ex- pansion and contraction range; its continued flow under load; its 140 OPERATIVE DENTISTRY poor edge strength; its spheroiding during setting, when not prop- erly mixed from a perfect alloy. It is also liable to injury between the time of introduction and complete setting through carelessness of either dentist or patient. The Extent of Expansion and Contraction of amalgam is not un- der the control of manipulation by the operator, but is controlled by the composition of the alloy both as to materials used and their proportions; as well as the method of their preparation. The Flow of Amalgam under pressure is the term applied to the tendency of amalgams to flatten or move from under stress. Most metals will yield or flatten under a given stress in proportion to the load, up to a given point, and then cease unless the weight is increased. However amalgam continues to yield as long as the pres- sure is continued even though it is not increased. This peculiarity in amalgam explains the phenomenon often ob- served in the mouth. Amalgams differ as to the amount of force necessary to produce flow, yet the peculiarity is exhibited by all amalgams. Edge Strength in a Filling is the term applied to the resistance a filling shows to stress upon thin margins at that portion of a fill- ing which covers the marginal bevel. Edge Strength in Amalgam. This depends first, upon the metals entering into the alloy. The greater the proportion of silver enter- ing into the amalgam up to seventy-five per cent, the greater the edge strength. Above seventy-five per cent it becomes more brittle. Second, the manner of packing. Third, the amount of actual union between mercury and alloy. Fourth, bulk at margin. The Maximum Strength will be obtained when the alloy contains just enough mercury so that the mass will take the impression of the skin markings after prolonged kneading between the thumb and forefinger. Any more or less weakens the edge strength. The Length of Time the Alloy Stands has an effect upon edge strength, as amalgams made from alloys lose their edge strength pro- gressively with time, the more rapidly the higher the average tem- perature. However Aged Alloys SJiow Less Variations in Expansion, Con- traction and Range, and artificial aging is resorted to for this rea- son and is done by annealing. This annealing produces an amalgam that shows more uniform and consistent properties. Annealing of Amalgam is accomplished by subjecting the alloy when freshly cut to either a dry or moist heat ranging from 110° F. AMALGAM IX THE MAKING OF A FILLING 141 to 212° F. for some hours or days. The lower temperature for a lonofer period produces the best results. Effect of Annealing. The artificial aging increases the contrac- tion, the flow, and the ability to withstand the crushing strain; the amalgam requires less mercury, and sets slower. The Alloy Showing the Least Expansion and Contraction ^\ hen unannealed is composed of seventy-two parts silver and twenty- eight parts tin and may be modified very slightly by adding a small per cent of copper or other metals. Wlien annealed the above for- mula of silver tin alloy should be changed to seventy-six parts sil- ver and twenty-four parts tin, to get a stable amalgam. Cavity Preparation for Amalgam. IMany of the failures in the use of amalgam attributed to the property of the material used are in fact due to laxity in cavity preparation, since many practitioners believe that thoroughness is unnecessary in this particular. The preparation of a cavity for the reception of amalgam is even more exacting than for gold, as the operator is dealing with a filling ma- terial possessed of a greater number of faults, each of which must be given consideration, and the cavity should be prepared in such a manner as to minimize these to the least degree. In compar- ing amalgam Avith gold it might be said that amalgam requires less access in awkward localities in the mouth, requires much separation in proximal fillings, and that the outline form must re- ceive more careful consideration as the margins must be farther removed from positions of great liability to caries, as well as stress. Flat Seats for Fillings are even more imperative than Avith gold, and the occlusal step must be broader l)ucco-lingually. The enamel walls must be finished Avith as great care, Avith a ca\''0-surface angle more acute, and a more deeply buried bevel angle. Cavities must have more retentive form. The Rubber Dam is very essential as it is imperative that amal- gam Ijc built against dry, freshly cut, walls and margins. It is as impossible to make a good amalgam filling as it is a good gold fill- ing against moist Avails. The residue from the saliva upon the Avails will shoAv leakage more quickly Avith the amalgam filling than with the gold. When operators come to the full realization of this fact and manipulate all amalgam filliugs Avith as gi'cat care as gold, with reference to dry conditions, the frequent failures of amalgam will be materially lessened. The Matrix. All cavities fillc*! w iiti amalgam must have coiiliii- uons sun-ouiidiiig walls. This will necessitate the adjustment of the 142 OPERATIVE DENTISTRY matrix in cases where a wall is missing and applies to all Class Two cavities which reach the occlusal surface. The matrix should be thoroughly wedged at the gingival, to pre- vent excess contour at this point, and to secure additional space that contact point may be made close. It should be made of steel as thin as one one-thousandth of an inch. It should be made to encircle the tooth firmly either by ligating or by a retaining appliance, several of which are on the market. When two proximal fillings are to be built at the same time and in the same proximal space, two matrices are necessary, one for each tooth involved. However, better results are obtained, particularly with reference to proper contact restoration, by building up and finishing one fill- ing first, and then building the other filling at a subsequent sitting. By using a specially prepared matrix band of the proper size for the second filling, with a hole cut in the matrix to allow" the metal to protrude at the point of contact w^ith the first made filling, an ideal result may be obtained. Separation. Preliminary or immediate separation is just as es- sential in the use of amalgam as gold. Making- the Proper Proportions of Alloy and Mercury. Each operator should test his favorite alloys and determine the exact amount of mercury for a given quantit}^ of alloy, and b}^ the use of a pair of balances be able to always mix in exactly the same pro- portions. By this means the operator is able to produce the best product by having the amalgam at its best. By the uniformity he becomes familiar with the habits of that particular alloy. This method need not be a time-loser, if the portions of alloy and mercury are previously put up in separate capsules ready for im- mediate use. In early practice this can be done by the dentist him- self at leisure times and in after years by the assistant. Making the Mix. Upon the thorough incorporation of the mer- cury with the alloy prior to placing in the cavity depends much of the good qualities of an amalgam filling. Poorly mixed alloys have little strength. Amalgamation in an amalgam filling is never entirely complete, and while this process is going on, there is a certain amount of molecular action, which tends to change the form of the filling as a whole. A very great per cent of this union may be in- duced before placing the filling by a thorough preliminary mixing and kneading of the mass. To this end the alloy and mercury should be put into a wedge- wood mortar and thoroughly ground together till the contents seem to have become one mass. It should then be removed to the palm a:mal(;;am ix the making of a filling 143 of the hand and made into a pcllot and then transferred to the thumb finger grasp and rolled between the fingers with sufficient force to produce a decided squeaking noise, sometimes spoken of as the "cry of tin."" p]ither too little or too much mercury will destroy this sound which should l)e sought. This kneading should be continued till the maximum plasticity has been secured, and the tendency to stiffen has just appeared. Wringing- Out Excess Mercury. All surplus mercury should be expressed as soon as detected. With small masses this is thoroughly and quickly done l)y grasping the mass between the ball of the thumb and the tip of the first or second finger. The flesh of the fingers should entirely cover the mass from view. Then by a rocking mo- tion in which the mass is kept entirely covei'ed the mercury svill appear from between the fingers and not carry Avith it any appreci- able amount of the alloy. If the mass is too large to keep entirely covered during the proc- ess, it may be placed in a chamois skin and wrung to dryness, or di- vided into pieces sufficiently small to be manipulated with the fingers. As soon as the excess mercury has been expressed the whole mass should be again kneaded, as it should not be allowed to stand in this compressed condition. The mass should be rolled between the thumb and finger into a loose rope, In-oken into pieces, and laid in a posi- tion convenient to cany to the mouth. The rope or ball of amal- gam should never be cut with instruments, as that part close to the instrument is compressed and rapid setting facilitated. Amalg-am Pluggers. The packing instruments sliouid l)e as large as can be well used in the cavity, that the whole mass may receive the force of compression at each effort. The face of the plugger should be serrated to prevent slipping. A l)all l)urnisher should not be used in packing amalgam, but is intended foi' finishing after the amalgam has set. Making- the Filling-. Tlie cavity should be in complete readiness to receive the amalgam immediately after it has l)een prepared. The size of the portions will depend upon the orifice of the cavity, and should be as large as can be easily crowded into the opening. This should be immediately compressed upon the seat of the cavity with as large a jduggei- as possible, with a rocking motion and as much •weight as the circumstances will permit. When using a point that is much smaller than the cavity, the same Avedging principle used in packing gold should be employed; that is, compi-ess the central por- tion of the mass first and against the walls last. A burnisher should not be used ; neithei- should the bui'iiishing nor \\i|)iiig motion be used. 144 OPERATIVE DENTISTRY but all compressing force should be directed at a right angle to the base wall. Quite a body of excess should then be added to the occlusal por- tion and a plugger point applied with mallet force which should be augmented with hard hand pressure. The hand pressure and mallet force combined will produce a more dense filling than by any other method and at the same time crowd the yet movable particles of amal- gam and alloy into closer adaptation to every portion of the cav- ity walls. Trimming' Amalgam Fillings. After packing the amalgam it should be allowed to set undisturbed for one or two minutes, when the excess may be cut away with suitable knives. Gum lancet No. 2 and the discoid and cleoid from the ''University set" are service- able, as are also the large spoon excavators. Removal of Matrix. The matrix should then be removed in prox- imal cavities by drawing to the buccal while pressing the ball of the finger gently on the occlusal surface. A loosely rolled, rather large, ball of cotton should be laid on the amalgam filling under the finger tip, in order to prevent the matrix from traveling occlusally in the process of removal. The rubber dam should then be removed and the patient instructed to slowly close the teeth, stopping the instant he feels the presence of the filling between the teeth, which will occur if excess contour has been built. With the teeth still held in this same position, the patient is requested to give the jaws a gentle side movement. This will result in burnishing the spots of contact, after which the excess should be whittled away with knife-edged instruments. Amalgam Should Be Cut From the Margins to the filling, Avhich is just the reverse from the travel of the instrument in cutting gold fillings. If the cutting instrument moves from the filling to the cavo- surface angle with amalgam that is only partially set, it is liable to sink too deeply into the substance of the filling and expose the margin as it crosses over. . Passing Contact Point. In proximal fillings of amalgam nothing of any description should ever be allowed to pass the contact point until the amalgam has completed the process of setting, as one such attempt forever destroys proper contact and a filling so treated be- comes at once a makeshift. All overhanging amalgam should be cut away, around the entire cavity outline, but the region of contact point should be entirely neglected at this time, and left for final shaping during the process of polishing. Finally the filling should be gently wiped with spunk or cotton. AMALGA:\r IX THE MAKING OF A FILLING 145 Polishing". All nmal^aiu tillinss should i-eeeive as thorough and careful polishing as gold. This must he done at a suhsequent sit- ting. In proximal fillings the separator should l)e adjusted and the contact point properly formed and polished. For this work ahradents of only the finest nature should he em- ployed. Burs, carhorundum stones, coarse strips and disks only do harm and ])rolong the operation. Fine stri])s. disks, wood points and leather wheels, using first pumice then whiting, and lastly the tooth polishing rul)ber cups should he used. CHAPTER XXIV. THE USE OF CEMENTS IN FILLING TEETH. Varieties. There are five main varieties of cement available for use in the operation of filling teeth; silicate, cement, oxyphosphate of zinc, oxychloride of zinc, sulphate of zinc, and oxyphosphate of copper. Cavity Preparation for cement when the entire filling is to be of cement is not unlike that for any other filling, except that the cavo- surface angle is left the same as that produced by the cleavage of the enamel, omitting the marginal bevel. The cavity should be given the usual retention form, and the matrix must be employed in cav- ities to supply the missing wall that the cement may be introduced with pressure to condense and create close adaptation to walls. The rules given for dryness in the manipulation of gold and amal- gam are also to be observed in cement filling. The silicate cements have been evolved in an effort to produce a cement that would more nearly harmonize with the color of the teeth ; to better withstand the action of the oral fluids and the abrad- ing effects of mastication. Berylite is a prominent illustration of a silicate cement. Some of the silicates are now used as independent fillings and are not suitable for use as a cement. This material as a silicate filling is given full consideration in Chapter XXV. Oxyphosphate of Zinc has many uses in the cavities of teeth as a partial filling and in some instances for the complete filling. Be- ing a poor conductor, it makes an excellent agent as an intermediate between metal fillings and closely approached pulps. Its adhesive quality gives it great value as a means of adding re- tention to all kinds of metal fillings. This quality together with its harmonious color with tooth substance makes it invaluable for lin- ing weakened enamel walls which have lost much of their support- ing dentine. Its Chief Fault is its tendency to dissolve in the fluids of the mouth, which renders it comparatively temporary. However there is a considerable variation in its behavior in different mouths; in some instances it wears for years. Oxychloride of Zinc is indicated in pulpless teeth to fill the pulp chamber, after the canals have been previously filled with gutta- percha, and for the lining of cavities for the preservation of color where adhesiveness is not of importance. It is not indicated in 146 THE USE OF CEMENTS IX FILLING TEETH 147 teetli ^vith closely approached vital pulp, or as a root filling, on ac- count of its irritating properties. Sulphate of Zinc, wlieu pure, is the least irritating of all cements and is one of the best materials for pulp protection. A pulp cap- ping of this material is of most universal application. Oxyphosphate of Copper is especially indicated in remote cav- ities on the necks of teeth occasioned by gum recession. Cavities which are so ill-defined that the use of amalgam or gutta-percha is difficult, may be successfully filled with this preparation of copper. It can be made to adhere very tenaciously to the walls of a cavity, thus obviating much cutting. Oxyphosphate of copper is also in- dicated in the small cavities in the deciduous teeth. It is claimed that this material exerts a therapeutic influence up- on the tooth substance, thus preventing further decay. Manipulation of Oxyphosphate of Zinc Cement. The method of mixing this cement is not in the least difficult, yet certain details are essential. The slab, preferably of smooth glass, should be clean. The spatula should be flat with the side slightly convex. Agate is the best material as it is not acted upon by the liquid. The liquid and powder should be placed upon the slab separately, the drop of liquid being carried there by the use of a small glass rod. The spatula should never be immersed in the bottle to obtain more fluid as this would destroy the efficiency of the liquid. Crystallized portions should be carefully wiped off the mouth of the bottle as soon as detected. Plan of Spatulating. The powder should be added to the liquid a little at a time and each portion thoroughly rubbed by a swinging circular movement of the spatula upon the slab. This rubbing should not be rapid or vigorous. For lining cavities, where thin layers are desired which are very adhesive, the cement will prove correctly mixed when it shows slight stringiness and when the first stickiness appears, as shown by the slight resistance offered the spatula in its movement over the slab. Where the entire filling is to be of cement, more powder should be added and the spatulation continued till the cement materially resists spatulation and the mass is the consistency of freshl}^ made putty. When cement is of the consistency desired no time should be lost in placing it in position, and it should be allowed to harden undisturbed. If the cement is to form the en- tire filling and permanency is desired, it should be crowded to place with .some force and rapidly shaped up. As soon as crystallization begins it should not be disturbed by manipulation till it has fully hardened, when it should he f)olishfd wilh fine Hlri|)s jiikI disks. CHAPTER XXV. MANIPULATION OF SILICATE IN THE MAKING OF A FILLING. Definition. Maierials for Silicate Fillings are marketed under trade names which no donbt snit the purposes of the various manu- facturers, and there can be no just criticism offered from the stand- point of the tradesman. However some confusion exists among the members of the dental profession as to the correct term to use which is broad enough to cover all of this class of fillings and not desig- nate any special make. We will therefore consider some definitions from Webster's ''Unabridged Dictionary." Silicate (a noun) "is a salt composed of silicic acid and a base." Silicate from which we make fillings is made by silicatization. Silicatization (a noun) "is the process of combining with silica, so as to change to a silicate," which is, chemically speaking, a syn- thetic process, — "the uniting of elements to form a compound." Porcelain (a noun). "A fine translucent kind of earthenware," named after the shell ' ' Porcellana " " either on account of its smooth- ness and whiteness, or because it was believed to be made from it." Cement (a noun) when used as a noun is, "x\ny substance used for making bodies adhere to each other, as mortar, glue, etc." Cement (a transitive verb). "To unite by the application of a substance Avhich causes bodies to adhere together." Cement (an intransitive verb). "To unite or become solid; to unite and cohere." Cementation (a noun). "The act of uniting by a suitable sub- stance." Chemical definition: "A process which consists in sur- rounding a solid body with the powder of other substances, and heat- ing the whole to a degree not sufficient to cause fusion, the physical properties of the body being changed by chemical combination with the powder; thus iron becomes steel by cementation with charcoal and green glass porcelain, by cementation with sand." Enamel (a noun). "A substance of the nature of glass, but more fusible and nearl}^ opaque, — with a variety of colors; also other ma- terials used for giving a highly polished ornamental surface." Ana- tomical definition: "The smooth, hard substance which covers the crown or visible part of a tooth, overlying the dentine." Fi^om the foregoing references to Webster it would seem that the term "silicate filling" is correct when used to name this kind of 148 silicatp: IX the making of a filling 149 filliiio material as a class aiul when used to restore lost tooth sub- stance. The use of the word '■cement" as a part of the name, hence a noun, is incorrect unless the substance is used to "make bodies ad- here together" and should be eliminated from the names of the silicates and other compounds intended for a filling per se, except when adhesive properties are taken advantage of. The term "synthetic" is correctly used when applied to any of the plastics now in use in dentistry, with a possible exception in amalgam, as chemists are divided in their opinions as to exactly what takes place in amalgamation. The use of the Avord "Porcelain" as a part of the name, its being correct or incorrect, depends entirely Fig. 79. Fig. 79. — Suitable cavities for the use of silicate fillings. Fig. Fig. 80. — A Class One cavity on the labial of a central incisor properly prepared for a silicate filling. The decays are shown in Fig. 79. upon our undei'standing of the degree of heat necessary to bring about cementation. (Sec definition.) This is accomplished at com- paratively low and ordinary temperatures with most of the makes. All are assisted in the process by temperatures slightly above that of the body, with one maker advising the melted jiaraffine bath dur- ing the period of setting. The use of the term "Enamel" is cor- rect provided it is a "substance of the nature of glass, more fusible. nearl.v opaque, used foi' giving a poli.shed ornamental surface." and the prefix of "Artificial" jn-ovided it is "a sul)stitute" for the nat- ural covering of a tooth's crowiL Tt would seem that the silicates are all synthetic, that they all partake of the natui-e of poi'celain. 150 OPERATIVE DENTISTRY that they are a trade enamel, that they are artificial when replace- ing the lost enamel of human teeth, that they are cement when used to hold a filling of other material in the tooth or when the material itself adheres to the tooth, and that they are not cement (a noun) when used as a filling per se. The author therefore takes the position that the filling material under consideration is ''silicate" as the correct manipulation of most makes eliminates adhesion to the cavity. Those which adhere to the cavity or will retain fillings of other materials in the cavity are for that reason a silicate cement. It therefore follows that with the use of silicate there must be retentive form in cavity preparation. At Fig. 81. Fig. 82 Fig. 81. — Extensive Class Three cavity properly prepared for a silicate filling. Decay shown in Fig. 79. Fig. 82. — A Class Five and a Class Three cavity suitable for the use of silicate as a filling. this time we find the best illustrations of this class of silicate in " De Trey's Synthetic Porcelain" and Ascher's ''Artificial Enamel," neither of which should be used as a cement. Cavity Preparation is quite similar to that for an amalgam filling and is here considered in the order of cavity procedure. Gaining Access. The access required for the silicate filling is the same as that for any other plastic filling, as far as its introduction is considered and the conditions sought at the time the filling is com- pleted. Contact point in Classes Two, Three and Four is just as essential, but is harder to maintain due to interproximal wear. It SILICATE IN THE MAKING OF A FILLING 151 would therefore follow that the primary contact should be greater and broader. In other words, if we are to use the marble contact it should be the contacting of larger marbles than in the more dur- able metal fillings. To put it in other words, the convexity of the filling's surface should be the segment of a larger circle than the metal filling. Proper separation is essential. Outline Form. In the consideration of outline form, the same rules should apply as when using any other filling. We should ex- tend cavity margins until all surface decay has been included. With other filling materials, we sometimes falter in this because of the un- sightly results, but with silicate, when the color has been properly chosen, there should be no hesitancy, as large fillings are generally Fig. 83. ' Fig. 84. Fig. 83. — A Class Five cavity properly prepared for a silicate filling. The decay is shown in Fig. 82. Fig. 84. — A Class Three cavity, lingual apjiroach, properly prepared for a silicate filling. The decay is shown in Fig. 82. as little observed as small ones, especially on flat labial and buccal surfaces. When fissures and sulcate grooves are encountered, they should always be included in the outline, as a leaky filling will re- sult at the triangular space formed where the sulcate grooves meet the filling. Resistance Form. In dealing with resistance to the crushing strain, wo have a greater problem to solve than in the use of almost any other material. The edge of the filling is more easily broken, and after some months or years of wear there is great danger of ex- posure of the cavo-surfacc angle. It is therefore necessary to lay 152 OPERATIVE DENTISTRY Fig. 85. Fig. 86. Fig. 85. — A small Class Three cavity, labial approach, properly prepared for a silica'.e filling. Fig. 86. — A small Class Three cavity, lingual apjn-oach, properly prepared for a silicate falling. Fig. 87. Fig. 88. Fig. 87. — A large Class Three cavity, labial approach, properly prepared for a silicate filling. Note the irregular outline on the lalsial. This is not objectionable, for many times an ir- regular outline hides a sli.ght deviation from the proper color. Fig. 88.- — A large Class Three cavity, lingual approach, properly prepared for a silicate filling. Note the fact that this cavity has two axial wails. This is a good form of preparation in vital cases. SILICATE IN THE MAKING OF A FILLING 153 the cavity outline in areas subject to as little stress as possible. In locations subject to great liability to stress, it is necessary to ex- tend the outline until full-lenoth enamel rods, supported by sound dentine, have been reached and then beyond that to a location not subject to the travel of the cusps of opposing teeth in the process of articulation. It is not necessary to pay much attention to devel- opmental grooves, for when these grooves are normally formed they are fully as strong as the material in hand. It is most important that all enamel eminences be avoided, as the material is quite friable and offers very little support to the cavo-surface angle. Retention Form. Provision against the tipping strain is the same as for other fillings and is more like that for amalgam. This Fig. 89. Fig. 90. Fig. 89. — A large Class Three civity |)ropcrly jjreiiarcd for a silicate filling. Note the small amount of dentine yet remaining near the incisal angle. While this angle can inoperly remain when using a silicate filling, it would be entirely out of the question when using co- hesive gold. Fig. 90. — Two extensive Class Three cavities projjcrly prepared for silicate fillings. In both of these cavities the dentine has been practically all removed at the incisal angles. Cases like these may be filled with silicate but should be regarded as temjjorary in a large majority of the cases. The retention of these angles after filling will depend entirely upon the amount of force to which they were subjected. They would be comparatively permanent in cases of ir- regularity when that condition [)laced these angles in a position removed from stress in oc- clusion and articulation. material only reaches its maxiniuiii strength to resist dissolution and the crushing strain when it has been so thickly mixed that it has lost practically all of its adhesive (|ualities. Therefore, the rules which apply to cavity pi'cpai'ation in refci'cnce to retention form would be the same as in the use of amalgam. We must have flat walls excepting the axial, flat seats of generous pi'o[)oi'tioiis and def- inite angles. 154 OPERATIVE DENTISTRY Convenience Form. This step in cavit^^ preparation for the silicate filling, as with other plastics, comes in for only a minimum consideration, as it is seldom necessary in the use of this material to make any changes to facilitate the making of the filling, for when other rules have been followed we find ample convenience for its in- troduction. Removal of Remaining' Decay. There is one major reason why all softened dentine should be removed from the cavity walls. The decalcified portion of tooth substance is always saturated with the acid of tooth decay, — ^lactic acid. Experience has proved that the crystallizing silicate will absorb this acid, resulting in a filling of weak structure. It would therefore follow that no softened dentine be allowed to remain in the cavity. Finishing- of Enamel Walls. With other fillings it has been found - -" — <~ J, MSH^Bfliii i ! iMiiiirfiiiiBiltBnilT^ 3 :^ ^ ^-•^Si' IRk_ fcMtt^fn 1- .^..^■r ^^^^ fifl^" ^^jL Wi ■-??--5*3?^- — -;•— ^srr ^^^^^ Fig. 91. — A small set of instrumencs for manipulating silicate. advisable to bevel the enamel margins from 6 to 10 degrees centi- grade. With all silicate fillings, this beveling seems to make an ad- ditional weakness and should be avoided as it will cause the filling to break at the margin, even though the procedure results in an im- perfect cavity, from a scientific standpoint. "We should determine that we have full-length rods and that we have found their direc- tion by complete cleavage and then omit the beveling. Toilet of the Cavity. To the ordinary toilet given for other fill- ings should be added the varnishing of the dentine walls, as a pre- caution against the material absorbing either acid or moisture from the walls or the absorption by drying dentinal walls of the fluid part of the filling, due to excessively desiccated dentine. Rubber Dam. The application of the rubber dam, or other means equally as efficient, should have taken place following partial outline SILICATE IN THE MAKING OF A FILLING 155 form. Prior to adjusting the rubber dam, the color or combination of colors should have been selected, as the opinion formed after the rubber dam has been in place for a short time is worthless as a guide to the proper shade to be used. During the early experience with this material, with each operator, the shade guide should be fre- quently used as an educator, but in a few months, the operator should begin to be so familiar with the resulting colors that no shade guide is necessary. Making" the Filling". When cavity preparation is completed, the proper material and instruments for making the filling should be Fig. 92. — A suitable slab and spatula for working silicate. The slab should be thick and heavy in order that when chilled it will remain at a low temjierature during the mixing of the silicate. placed in a handy position. Absolute cleanliness is imperative, par- ticularly during the process of mixing, as otherwise the filling when completed will not be chemically pure. The mixing slab should al- ways be kept scrupulously clean, should not have a scratched sur- face and should be without color. This last point is to avoid any effect color could have on the judgment as to the shade desired. A good slab is produced by taking a large-mouthed bottle and filling it with cold water, or even ice water, in order that during manipula- tion the material may be held at a low temperature. Before using a thick glass slab (Fig. 92) chill to a temperature of GO degrees or a little below. The temperature feature in this manipulation is of imj)ortance. With nearly all of the pi-ocesses in the filling of teeth wherein the dentist depends upon sul)sequent chemical action for 156 OPERATIVE DENTISTRY a final result, cheinical action should be either retarded or held in check during the entire process of manipulation, which is easily accomplished by a low temperature mix. "The process of set- Fig. 93. — Proper position of the spatula on the slab when manipulating silicate. Fig. 94. — Proper placing of the materials when manipulating silicate. ting" as it is called is held in check until the material is finally in place and further disturbance unnecessary. As soon as the filling has been placed in the tooth, the warmth of the body is sufficient SILICATE IX THE MAKING OF A FILLING 157 to hasten the eheiuieal action and l:)etter results Avili be secured. "With most of the silicate fillings, the body temperature is suf- ficient: with others tlie best i-esult can only be obtained by keeping Fig. 95. — Taking the first portion of the i)0\vder whic'i should bi- aliout half of the entiri amount needed. I-'ig. 96. — fncorporatinf; the first portion of the powder. llic filling for a sliiot time biillictl in nu'ltcd pai-aflinc. Tlu' mix- ing slal) slionbl be ill as b)\\' a Icnipcrjil urc as i)ossibb' and shonbl not }»i-odiicc disconililnrc to Ihc palicnl. A Icnijx'ralui'c of (iO degrees 158 OPERATIVE DENTISTRY seems to be as low as can be borne by the patient when placing a filling in a vital tooth. It is therefore quite practical to use a bottle slab wherein the thermometer reaches 55 to 60 degrees, as no doubt the temperature of the filling is about 68 when placed in the tooth. It is quite possible to use a bottle that contains iced water when the filling is to be placed in a non-vital tooth. .At such times when the atmosphere is close to the dew point, as is evidenced by the condensation on the fountain cuspidor, there will be trouble about the formation of moisture on the cold bottle. . When this is only slight, it does not seem to damage the filling. However, when the condensation is sufficient to be noticed, or is excessive, the den- tist has to either content himself with manipulation at a higher temperature or postpone the operation to a time when the atmos- phere is above the dew point. The spatula must be of some ma- terial which will give off none of its substance during the process of mixing. For this reason the agate is the best and most popular. Fig. 91. — Illustrating the circular motion which should be given the spatula in mixing a silicate filling. Note that the spatula should be moved first in one direction and then in the other as indicated by the arrows. Also that the spatula describes segments of small circles and that the material is not spread over any considerable surface of the slab. Begin the mixing only when the cavity is prepared and dried, and the filling instruments are laid out and ready for immediate use. While there is no great haste as long as the material lays on. the cold slab, there are left but a few seconds to make the filling after the material has been removed from the slab, on account of the rising temperature hastening chemical action. Preparing Materials. First pour out near the end of the slab to the right, the amount of powder the mix is liable to require, and then place stopper in the bottle. With the dropper place the proper quantity of liquid near and to the left of the powder. Im- mediately return the dropper to the bottle and secure the cap to prevent evaporation. The best results are obtained when no less than three drops of liquid are used for the mix. Do not shake the liquid bottle. Make the mix promptly, for if there is any consider- able delay, the chemical formula of the liquid may be changed, due SILICATE IX THE MAKING OF A FILLING 159 to an evaporation in a dry atmosphere or the addition of water in taking np the condensation from the cold slab at low barometer. Making- the Mix. Begin ^^'ith sufficient liquid on the slab and do not add any more at that stage. Mix by drawing into the liquid about one-half of the total amount of powder required to make the completed filling. Begin the mix by spatulating with a light rotat- ing movement ; hold the spatula flat on the slab, describing the arc of a small circle with a diameter of say one-fourth of an inch. As soon as the poM'der has been all incorporated and the mass ren- dered uniform, scrape all of the mass off the slab with about three strokes. Take one-third of the mix each time. This assists in se- curing uniformity of the mass. Then put it back on the slab this Fig. 98. — The last stroke of scraping the material from the slab. time getting all off the spatula. Do not scrape the spatula on the edge of the slab, but place it flat on the slab, holding it firmly and giving it a turn in the hand, Avhich will practically clean it. Here more powder is added, a small portion at a time, and incor- porated in the mass already mixed, by the method of crowding, which is done by rolling the spatula first against one side of the mass on the slab and then against the other. The addition of the powder by this crowding process is continued until the mass l)e- comes of a consistency of putty, losing practically all of its adlie- sion and giving only slight evidence of a tendency to follow the spatula from the slab. The Proper Consistency is reached when the mass has been mixed 160 OPERATIVE DENTISTRY SO stiff that the material just loses its gloss when being crowded by a rotating spatula, yet can be made to show a glossy surface when patted three or four blows with the spatula. In case the material looks very wet and glossy the mix is not yet stiff enough. If the three or four blows do not produce gloss, the mix is too heavy and must be entirely discarded. Time of the Mix. The lower the temperature at which the sili- cate is mixed the longer may be the time of manipulation ; also the thinner the mix, the longer wdll it be before the chemical ac- tion of the setting will be noticed. By using the cold process of mixing, the time of manipulation is lengthened and the time of set- rig. 99. — The entire mix on the spatula. \ i.^ Fig. 100. — Illustrating in three successive steps the method of removing the mix from the spatula to the slab. ting after leaving the slab is materially shortened, due to the thick mixture obtainal^le. Making the Filling. It is important that all moisture be ex- cluded, as we cannot manipulate silicate under moist conditions. Agate or ivory instruments are preferred for placing the material in the cavity. Those of bone or shell will do. If the instruments are absolutely clean and polished so that they wall give off no sub- stance in the material, it is possible to place the silicate in the cav- ity with steel instruments and get no subsequent discoloration. Fill the cavity slightly to excess with absolutely clean instruments by taking a quantity, one-half of that required to fill the cavity, and crowd or wipe the material against every portion of the cavity walls from cavo-surface angle to cavo-surface angle. The second time, take up a sufficient quantity to more than fill the cavity. SILICATE IX THE MAKING OF A FILLING 161 Crowd this into position and hastily get a partial contour. Ini- niediately pat or paddle the material to complete contour, continu- ing until the material has been crowded slightly over the margins. This paddling force will jar the material so as to bring back the gloss, as produced by patting on the slab. In case the gloss is not produced by the paddling, a homogeneous mass is not secured and the fill- Fig. lijl. — i'loijcr (.oiisistency of silicate, for inimcdialc introduction into the cavitv Fig. 102. — This mix of silicate is yet too thin and there should be more powder added. The material should show a tendency to follow the spatula when moved from the slab but it should not follow the sjotula as here shown. ing will lack proper cobir, will be of poor edge strength, and will make a very weak filling. Jf the glo.ss has ])0("ii i)roduced by the paddling or jarring of the material, it should be allowed to remain undisturbed until the process of setting has sufficiently taken place that the body of Uic filling will not be moved l)y any work ii])on its surface. 162 OPERATIVE DENTISTRY The Use of the Matrix either upon the posterior or anterior teeth should be the same as that for the introduction of the amalgam filling. With Class Three fillings, one end of the matrix is left loose until the cavity has been filled more than full with the ma- terial. The loose end is then brought over the tooth and tapped on the outside of the surface as it is being tightened upon the filling. This jarring process of bringing the matrix to position results in a homogeneous mass beneath the matrix. Immediately after pad- dling the filling and the detection of the glossy surface, the filling is to be entirely coated with cocoa butter to exclude the air during the process of setting. Finishing- the Filling-. After the filling has been allowed to stand undisturbed for three or four minutes (no longer), there should be applied a very thin-edged knife or chisel and by a scraping motion Fig. 103. — A homemade mallet and point used by the author in paddling and jarring silicate to position in the cavity. The mallet should be of light weight and have a soft sur- face. The plugger point here shown is made of platinized gold. Tandilum would be better for this provided it had a handle attached which was of very light material. It is quite neces- sary in this process that both hammer and plugger point are of the least possible weight. parallel with the cavity outline the excess is cut away to within one-tenth of a millimeter of the cavo-surface angle, at the same time reducing the general contour to that desired, keeping the filling submerged in the cocoa butter. When the filling has been in position five or six minutes, very fine strips or disks coated with cocoa butter may be used to produce the desired gloss. The author prefers to leave the filling with file and knife finish and has aban-' doned the use of strips and discs as injurious. This completed filling should be scrubbed with cotton balls in order to remove all of the cocoa butter possible and the finished filling painted with a copal-ether varnish. No varnish of which alcohol is a part should be used. Evaporate to dryness with air, remove the rubber dam a.nd test for occlusion and articulation, provided the filling in- SILICATE IX THE MAKING OF A FILLING 163 volves the occlusal or incisal surfaces. In case the filling is found to strike the apposing teeth, the excess should be ground off with fine carborundum wheels, and again varnished. It is entirely safe to use carbon paper to print these fillings, the same as with gold or amalgam and its use will not cause discoloration of the filling. The instruments used in reducing the size of silicate fillings should be the same as when reducing the bulk of a gold filling. The manufacturers of some of the silicates advise not to use any steel Fig. 104. Fig. 104. — Three cavities suitable for silicate fillings. Fig. 105. Fig. 105. — This shows the results obtained after filling with silicate the cavities shown in previous figure. instruments in the finishing of these fillings, but clinical experi- ence has proved that any injury Avhich can result is not due to the instruments, but to their unclean condition. Facing Metal Fillings with silicate is many times of advantage and is at this time tlie only method wherein it is advisable lo use silicate in connection with angle restoration in Class Four fillings. This will be more fully discussed in Chapter XXVIII dealing with Combination Fillings. (Sec Figs. lOG, 107 and 108.) CHAPTER XXVl. THE USE OF GUTTA-PERCHA IX FILLING TEETH. Gutta-Percha has its place in various operations upon the teeth. It is not acted upon by the fluids of the mouth and is quite permanent when placed in locations protected from the force of mastication. It is a good tooth preserver as decay does not readily take place in cavities so filled. Base Plate Gutta-Percha is the best form to be had. It comes in the -white and pink colors, the last named being the most dur- able in positions exposed to wear as it gets the harder upon cooling. Filling- Cavities with Gutta-Percha. This material is indicated in subgingival cavities, both buccal and proximal, where a fill- ing that is a very poor conductor of heat is desired, on account of close proximity to the pulp, the pulp being not yet exposed. It is also indicated for those distressing cases where there is a decay started in the occlusal surface of a lower third molar which has erupted with its occlusal surface at an angle of about forty- five degrees to the distal of the second molar. Such cases cannot as a rule be properly extended to cheek decay in the use of amal- gam or gold. The gutta-percha filling will check decay and if renewed at stated periods will produce sufficient separation for correct filling or to render extraction easy. Method of Preparation and Filling. The cavity should be freed of all decay and the cleavage of the enamel secured, omitting the marginal bevel. The cavity should be sterilized and dried, then slighth' moistened with campho-phenique or eucalyptol. The gutta-percha should then be warmed and immediately crowded to position. Care should be taken that the material is not overheated as slight burning destroys the durability of rubber. The gutta-percha should be introduced piece by piece sufficient to a little more than fill the cavity. The surplus must be wiped off flush with the cavity margins with warmed burnishers. Finally the surface should be wiped with a cotton ball carrying chloro- form. For Root Canal Fillings. The gutta-percha is dissolved in chloro- form to the consistency of molasses, and carried to the canals by 164: GUTTA-FERCHA IN FILLING TEETH 165 dipping a smooth broach in the container. The canals should have been previously flooded Avith oil of eucalyptol, and the chlora- percha mixed with the eucalyptol in the root canal resulting in Avhat may be termed euco-percha. The eucalyptol may be added to the chlora-percha in the bottle, but the method given first is for various reasons the better. For Canal Points. Gutta-percha is the standard material for canal points Avhich should be at hand in various sizes to suit all oases. These may be manufactured by the dentist, but with little econ- omy, as they are well made by machinery. Tliose Mhich are flat- tened on the larger end are the most handy to use. Such may be had from your dealer, or the assistant can flatten them as pur- chased by placing them on a glass mixing slab and-pressing each larLi-e end Avith a smooth cold steel instrument. Slow Separation. Gutta-percha for slow separation in proximo- oeclusal cavities is unexcelled, the force of mastication doing the Avork sloAvly but surely. This fact prohibits the use of gutta- percha as a permanent filling in Class Tavo cavities. Temporary Stopping, as purchased from the dealer, is gutta- percha to Avhich Avax has been added to render it more plastic Avhen Avarmed. This is ideal for sealing in dressings, excepting when arsenic has been used, in Avhich ease poorly mixed amalgam is better. CHAPTER XXVII. TIN AS A FILLING MATERIAL History. The first use of tin as a material for filling teeth would seem to date back to about 1780 and was much written about as a tooth preserver for the century following. After the introduc- tion of amalgam in 1826 there seemed to have been much rivalry between the two substances, amalgam gaining the favored position. At the World's Columbian Dental Congress, in Chicago, 1893, as will be seen by the report, many dentists of national repute went on record as classifying tin as one of our best tooth savers and de- plored the fact that its value was being lost sight of. The late Dr. W. C. Barrett expressed himself so emphatically as to say, ' ' Tin is as cohesive as gold, and if everything were blotted out of existence with which teeth could be filled, except tin, more teeth would be saved." This may be putting it a little too strongly, but the fact remains that more teeth would be permanently saved if a more general use of tin was common with the profession today. Therapeutic Value of a Tin Filling-. Of all our filling materials there are only two for which any therapeutic value is claimed. All others prevent the farther loss of tooth substance by exclusion ; mechanically shielding the defenseless tooth substance from the dissolving properties of the products of fermentation. The Therapeutic Action of Tin is probably due to the formation of the sulfid of tin which is caused by the presence of sulfuretted hydrogen from the decomposition of food substance. The dentinal walls of a cavity which has been filled with tin for some time, turn brown or black and seem to have undergone a structural change rendering them quite impervious to decay, and very hard to ex- cavate with hand instruments or the engine bur. Discoloration. In some mouths tin turns black not only upon its external surface but this color is in a measure transmitted to the tooth substance, a fact which is one of the greatest objections to its use and debars it from exposed positions in the anterior por- tion of the mouth. In other mouths there seems to be little dis- coloration, the filling remaining polished and of a light color. The Amount of Discoloration seems to bear no relation to its permanency as to bulk or as a tooth preserver. Thermal Conductivity. Tin is only one-fourth as good a con- 166 TIN AS A FILLING MATERIAL 167 ductor of heat as gold, hence, indicated under gold fillings in deep- seated caries Avith vital pulp. Indicated in Rapid Caries. In caries of a light or Avliite color indicating the most rapid form of decay, tin is of peculiar advan- tage, particularly in regions removed from view and protected from the wear of mastication. Tin in the Teeth of Children. There is no better material for fill- ing the teeth of children than tin. The principle of mechanical ex- clusion depended upon with other filling materials to prevent re- current decay does not seem to be sufficient in the rapid form of decay met with in both temporary and permanent teeth in the mouths of children particularly during the age of rapid develop- ment as found before the age of fifteen or sixteen. The additional advantage of the therapeutic influences of tin seems to be sufficient to check this rapid progress of decay till a period is reached when the process of tooth destruction is less apparent, due to more hy- gienic conditions in the oral cavity. Cavity Preparation for Tin. The cavity preparation for the use of tin is not unlike that given in the chapters on cavity prepara- tion by classes for cohesive gold. It will be of advantage if the convenience angles are a little more distinct, and the general re- tentive form throughout should be emphasized. The bevel angle should be a little more deeply buried as the edge strength is not as good as hammered gold. However the edge strength is better than amalgam. Tin has no tendency to spheroid like amalgam. Its flow is similar to that of gold but gi-eater with the same given load and like gold it is capable of being so condensed that it will stand repeated stress of a given load within a limited range and shoAv no flow. Forms of Tin. Formerly the only form of tin to be had for this purpose Avas the sheet tin. This was manipulated in much the same way as cohesive gold except that it required no annealing. It was then, and is yet, sometimes combined with gold by rolling a sheet of pure tin with a sheet of annealed cohesive gold into rolls, the gold on the outside and condensed in the usual manner using a large proportion of hand pressure. At present there is on the market a form of tin prepared in the shreds, which appears like a mass of coarse silver-colored hair. This is removed from the tube and shaped into pellets of suitable size and placed in the cavity in the manner one would place pellets of gold. Methods of Introduction. Tlio lubbci- flnm or other efficient 168 OPERATIVE DENTISTRY means of dryness must be used. When one of the surrounding walls is missing as in proximo-occlusal cavities in bicuspids and molars (Class Two) the matrix must be in place. The first pellet of tin introduced should completely cover the base of cavity and be thoroughly condensed by good steady hand pressure, with points at least one square millimeter in size employing the rock- ing motion. The points should have deep serrations and be so stepped as to include the entire surface. This hand pressure should be followed with the mallet force using a plugger point of medium serrations and the surface en- tirely gone over. A new pellet may now be applied and the plan just given repeated. If the filling is to be entirely of tin the cavity should be filled to excess and by a process of burnishing, con- densed and rubbed to the size desired. This last method gives a surface of the greatest density possible. Tin and Gold. When the filling is to be completed with cohesive gold little dependence should be put upon the gold adhering to the tin as the union is only slight. With a round-pointed instrument new convenience angles should be made in the substance of the tin near the line angles. The remainder of the cavity should be retentive independent of the space occupied by the tin. Tin and Amalgam. No special care is needed when the filling is to be completed with amalgam. Amalgamation takes place in that portion of the tin next to the amalgam proper and the union is quite strong, even more than tin to tin. The amalgam should, if possible, be more thoroug?dy mixed and the process of kneading prolonged that all amalgamation possible be secured before con- tacting with the tin as the tin will take up some of the mercury from the amalgam for which it has a great affinity. This is liable to injure the amalgam as to strength unless the mixing has been thorough. The use of tin and amalgam is not advised where the surface of the tin is to be exposed by forming any portion of the contour as the presence of the mercury absorbed causes the tin to rapidly disintegrate. Gold should be used for topping in such cases. Tin in Bifurcated and Punctured Roots. When through decay or by accident the cavity extends to the exposure of the peridental membrane the use of tin has no substitute. The opening should be rendered as clean as possible, sterilized and dried. The open- ing should be covered with a mat of pure tin made from foMed sheets, being lightly burnished to place and covered with amal- gam and the cavity finished with the desired material. CHAPTER XXVIII. COMBINATION FILLINGS Definition. A eoinbinatioii filling is a filling composed of two or more distinct snbstances introdneed into the cavity separately. Objects of a Combination. The object of combining various ma- terials in the filling of a tooth's cavity is to secure a perfect fill- ing, one possessed of all vii-tues, and no faults. Many such com- binations of material meet this demand in a large measure by bringing into service the strong features of each material, and at the same time nullifying the faults of all material entering into the construction. Since dentistry has been raised to the dignity of a science there has been a diligent search to discover a filling material which pos- sesses the virtues of all and the faults of none in present use. At the present time this is more nearly reached by the various com- binations possible with the usual distinct materials. If perchance the ideal filling is ever produced, dentistry will at once become much simplified as to methods of procedure. Single Materials Used as a Filling. There are only two filling materials now in use which are used in their pure state, pure gold and pure tin, and there are many instances where these combined Avith each other or Avith other materials, Avill produce better results than Avhen used alone. Gold and Tin Combination. This condiination is of service in large cavities of Class Two which are subgingival and in large oeclu.sal cavities in molars, where the i)ulpal wall is deep and rounded. In this combination the tin should be placed in the cav- ity first and thoroughly condensed, and the filling com])leted with cohesive gold. In Class Two the tin should cover the gingival Avall at least one millimeter deep and be condensed to ])la('o with Uie mali'ix in position. Benefits derived. Dcniinc upon wliich has been built a thor- oughly condensed tin filliny- docs not readily decay. Bv com- pleting the filling A\ith gold the discoloi-ation of tooth substance is avoided and the gold will bettci- i-esist the force of mastication. Gold and Cement. The ol^jcct of this coinhination is to ]U'oduce a filling tliat is adhesive, will ])rotect A\cal< ANalis, and resist the lluids of the mouth and the force of mastication. ](]9 170 OPERATIVE DENTISTRY Two Methods of Combining'. There are two methods of produc- ing this combination. One is to cast the filling and lay it into the cement-covered cavity, which is the inlay method. The other is to build cohesive gold into a thin mix of soft cement with which the walls of the cavity have been coated. The essential feature of both is that the cement be completely covered to protect it from dissolution by external agencies, as the fluids of the mouth and the effects of wear. When Indicated. The inlay combination is indicated in large cavities of easy access. The built-in method of combination is in- dicated in small cavities of more difficult access, and where cor- rect cavity formation is impossible or ill-advised. When using this method convenience angles may be omitted. Gold and Platinum. This combination adds to the many virtues of cohesive gold fillings by increasing the resistance of the filling to the wear of mastication. The pure gold is first used as it is capa- ble of more perfect adaptation to the walls, all of which should be covered before taking up the platinized gold. The contour por- tion should be made of the alloy. This alloy comes from the sup- ply house in sheets which appear to be pure gold except that the color is a little lighter. This foil comes in three numbers, 1, 2 and 3, the No. 2 being preferable for most cases. The rules for condensation are just the same as for pure gold, only the observance of each specific rule giVen on that subject is more emphatically demanded here, and when strictly followed the alloy will prove as easily handled. Cohesive Gold and Non-Cohesive Gold Combined. By this com- bination much time is saved as the non-cohesive gold may be in- troduced in greater masses than the cohesive. Also the soft gold is more easily adapted to the walls than cohesive. The cohesive gold is used to finish the contour as it will better resist the torsion strain and the effects of abrasion. Before the introduction of cohesive gold all gold fillings were non-cohesive, but since the introduction of the former the art of filling teeth well with soft gold has rapidly declined, so that the making of an entirely non-cohesive gold filling is now the exception. Cement and Amalgam. Results similar to what might be termed an amalgam inlay are produced by coating the prepared cavity with cement, and immediately burnishing into this fresh cement, a por- tion of the amalgam. The enamel margins are rendered clean COMBINATION FILLINGS 171 again by freshly cutting them with a chisel for their entire outline and the amalgam filling immediately finished in the usual way. The Benefits. This combination produces a filling with the vir- tues of an amalgam to which is added the adhesion of the cement and the protection of cavity wall from fracture and discoloration When Indicated. This is indicated in most large cavities to be filled with amalgam, where the walls are weak and thin and in cavities where insufficient retentive form is secured. Cement and Porcelain. Cement is combined with porcelain in the filhng of teeth for the purpose of making the filling adhere. The porcelain protects the cement from dissolution. Silicate Cement and Fused Porcelain. Fused porcelain inlavs g^o^^^-^iJ:^.^°^ -- -f -^, d^-^^!iii!j^i^\^-X ^n [:isr »^ 16- ■•"". — \-oirioinaiion ready to receive the silicate may be set with some of the silicate cements to great advantage. The silicate filling materials which are at their best when mixed thin enough to be adhesive are those which can be used as a ce- ment. In fact some operators are using these materials for setting the gold inhiy with seemingly good results. Silicate and Gold. Silicate may be used to face the gold fillino- lor esthetic reasons. In filling Class Four cavities with the gold inlay, by either one of the four phins, the wax may be cut out of the pattern so as to present a labial surface almost entirely of silicate. After these two materials are combined in this class of cavity, care should be taken that the incisal edge is of gold and 172 OPERATIVE DENTISTRY particularly that the cavo-surface angle on the incisal outline is protected by one-half of a millimeter to a millimeter of the cast gold. The cast should be made and set with oxyphosphate of zinc cement. At a subsequent setting the silicate face may be built in. A similar effect is produced with the bicuspids and molars, in crown work. The gold crown is made in the usual way and set. A carborundum stone is applied to the buccal surface and ground away and a sufficient amount of cement cut out to make room for the building in of the silicate. Before building in the silicate it is best to coat the cement which is exposed within the crown with a thin application of copal-ether varnish. Silicate and Amalgam. Many large contour amalgam fillings on the mesial surfaces of bicuspids and molars i)articularly in the Fig. 107. Fig- 108. Fig. 107. — Amalgam in position ready to receive a partial facing of silicate. Pig 108— This represents the amalgam filling shown in Fig. 107 with the silicate facing built in. The dotted line shows the outline of the silicate with that portion marked x, repre- senting the silicate. superior teeth are unsightly. A very pleasing effect is produced l)y cutting away the mesio-buccal contour of amalgam, either in new or old fillings, and in the resulting cavity, build silicate. The silicate will not discolor when thus applied to the amalgam. How- ever, each individual case seems to require a different shade and to get it right a trial mix should be made before deciding on the combination of powder to produce the desired shade. Silicate as Applied to Prosthetic Work. It is not Avithin the scope of this book to deal with prosthetic procedures. However, it is well to call attention to the fact that this material is used to COMBINATION FILLINGS 173 advantage in the facing- of crowns, the fitting of gingival ends of porcelain pin crowns to the root, and its application to many places in pieces of bridge work. It is also useful in the facing of Ijartial and full removable dentures in a color to imitate the natural gum tissues. There are many other combinations which are made and used to advantage in tooth salvage. It is improbable that the perfect filling material will ever be produced as the demands are so varied in different mouths, and in different localities in the same mouth. "We are more nearly able to meet all of those varying conditions by a wise selection of the materials to be used in each case and a judicious combination will go far to produce the perfect filling for each individual cavity as presented. PART III CHAPTEK XXIX. EXAMINATION OF THE MOUTH LOOKING TO DENTAL SERVICES The First Duty of a dentist to one presenting himself for dental services is to comply with the patient's request, which is generally to examine a special tooth or a diseased condition of which the patient is aware. If the patient does not make such a special re- quest it is well to ask some form of a leading question as to the reason of the call. This fact elicited, all else should be ignored until the object of the first visit has been accomplished. A Light Hand and Slow Movements are very essential for the first few moments, especially at the first meeting of patient and dentist, as first impressions are often lasting and if the stranger is ap- proached in a careless manner he may get ideas of undue rough- ness, many times unfounded, yet, nevertheless, lasting with the nervous patient. The Washing" of the Hands in the patient's presence or in run- ning water within hearing of the patient should be universally practiced no matter if the operator knows his hands to be already scrupulously clean, as it assures the patient that the operator has a regard for at least the simpler forms of cleanliness. The Linen Upon the Chair should be inviting and unsoiled. If convenient, it is well that the patient see that which is already on the chair changed for fresh. Few Instruments should be in sight, as they serve to remind the patient of former experiences not always pleasant. After the First Requests of the patient have been complied with it is well to take a rather general survey of the mouth before an- swering many questions regarding the advice to the patient as to future procedures. The operator should note in this "bird's-eye view," as it Avere, the probable care that is being bestowed upon the teeth and mouth in a prophylactic way. Also the health of the soft tissues, the number of extracted teeth, the presence of den- tures and amount of dental Avork previously done, noting its qual- ity and probable age, as well as the number of badly decayed teeth yet unfilled. He should note the health of the patient, probable 174 EXAMINATION OF MOUTH LOOKING TO DENTAL SERVICES 175 age and habits. All this can be done at a glance and in a few second's time, Avhen the operator will be much better qualified to advise the patient as to Avhat is best to do in a special case. If the Patient Is in Pain its alleviation is of first importance and should receive immediate attention. It may require the applica- tion of medicinal remedies, or some mechanical procedure or even the extraction of a tooth, but, whatever it may be, it must be done at once as the patient is in no mood to receive sage advice about the future when he is at present in pain. Early in the Examination Sitting- the patient should be advised of the necessity of a prophylactic treatment provided the teeth and mouth are not scrupulously clean, which is seldom the case, nnless the patient has recently visited the dentist for that purpose. This Is Second Only to the relief of pain and it is manifestly the dentist's duty to attend to prophylaxis before proceeding to the making of fillings. A Careful Examination should be suggested, folloAving the hasty inspection, and, if advised to do so by the patient, the dentist may then proceed to search all surfaces for the various classes of decay, not forgetting the vulnerable points about Avork previously placed, as the margins of fillings and about the bands of crowns. The Instruments Needed are, a clear, uninjured mouth mirror, a sharp pointed instrument called an explorer , cotton pliers and small balls of absorbent cotton, waxed floss silk, chip blower and mechanical separator. A small electric mouth lamp is also of value. The Use of the Mouth Mirror is to see therein the image of sur- faces and locations where direct vision is impei-fect or impossible and to flood the point being examined with an abundance of light. Many cavities existing in the proximal spaces are not noticed until strong rays of light from a different angle than the line of vision of the examiner have been dii-ected against them. The Use of the Explorer is to note the extent of decalcification at suspected points and the inspection ol' pits and grooves for faults in enamel. This instrument should be in the shape of an elongated cork screw turn, that the more inaccessible points may be reached. A light hand in i1s use is iin])('fative as the dentist is not excu.sed for breaking (lov>n tooth substances or for causing much pain in any of the processes af examination. Absorbent Cotton in the pliers is used to take up the moisture in cavities of considerable si/e and wliosc depth ([ucstions pi'oxiniity 176 OPERATIVE DENTISTRY to the pulp ; also sensitive surfaces suspected in shallow cavities, particularly those in the gingival third. The cotton balls should not be too large and rather tighth^ rolled. Waxed Floss Silk is used to examine the proximal space where the reflection of light does not make diagnosis positive. It cleans the surfaces of debris and food particles, giving a deeper insight from the embrasure. When surfaces are roughened or cupped from incipient caries, it will show by the catching or cutting of the fibers of the thread ; if the surfaces still retain their normal polish the thread will pass uninjured. The Chip Blower is a small hand bellows for the expulsion of air and is used in examination of the teeth to blow away and evaporate the moisture from points where it is held by capillary attraction, giving, thereby, a better view and a more correct idea as to the color present, which is a strong factor in a diagnosis of conditions. The Mechanical Separator will sometimes be of service to gain a little added space for the inspection of contacting surfaces. The Use of the Electric Lamp on the lingual side of the teeth has many advantages and is a speedy and sure way of detecting any of the stages of caries in the proximal spaces, the vitality of a tooth's pulp as well as abnormal conditions about the alveolar wall and the presence of pus and inflammatory changes in the maxillary sinus. When the Examination Is Completed the patient should be ad- vised of the true condition of his mouth, including the indicated treatment of both hard and soft tissues. If the patient indicates a desire to have the services rendered as outlined by the dentist it is entirely good business, and by no means unprofessional, to ap- prise the patient of the probable cost of the work as planned when it can be approximately estimated, unless the patient is a frequent visitor and familiar with the -charges expected from the dentist con- sulted. CHAPTER XXX. THE ALLEVIATION OF DENTAL PAINS. The First Duty of the Dentist is to relieve suffering, and as in many instances this is the reason for the first call of the patient it is most essential that the relief sought is obtained. Many times the relieving of a paroxysm of pain by the dentist has made a lifelong friend and patient. The Diagnosis is a most vital point and the battle is half won when tliis is correctly made. Pay Strict Attention to What the Patient Has to Say as he is quite sure to give you his symptoms in the order of their prominence and it is generally the prominent symptoms that are pathognomonic. After the Patient Has Given the Most Aggravated Symptoms, make an examination of the afflicted part of the mouth to verify the statements made. If all is not clear quiz him more specifically. Do not jump at conclusions. The patient is generally right as to symp- toms but frequently wrong as to location and cause. These last are the points the dentist must decide, as well as upon the treatment for relief. There Are Two Divisions of Dental Pains, those arising from lesions of the tooth pulp, and those arising from degenerative changes in the sub-dental tissues, which are generally the sequela of the same destructive processes in the pulp. They may follow the pulp troubles or occur simultaneously with them. Pulp Lesions. Symptoms are sensitiveness to thermal changes. The tooth is not necessarily sore to percussion. Pain is increased or induced when assuming a recumbent position. The presence of foreign substances in the tooth cavity cause pain especially when pressed against the walls of the cavity. Pain comes in paroxysms with a tendency to intermittence. Patient may complain of ''jump- ing toothache." These symptoms may all be present in the same case or only one at a time in the series of changes that take place ill M pulp from the initial affection to its death. The Treatment for Speedy Relief is varied according to the most jtroiniiicnt syiii[)1()iiis, ;is llicsc are the indications of the stage of dis- sf)lutioii. If Cold Air or Water Causes Pain of a quick, sharp, shooting na- ture. coiiK's on suddenly and passes off immediately upon the tooth regaininjr the body ternixTalure, the }>ulp is in the stages of active 177 178 OPERATIVE DENTISTRY hyperemia, which is the initial stage of a destructive disease, and will respond immediately to the application of anodyne and effectual protection from air and fluids, which is accomplished by stopping the cavity with a non-conductor, generally cotton, or temporary stop- ping, or an application of phenol. If Warm Fluids Cause or Intensify the Pain and the application of cold relieves the pain temporarily, the pulp will be found to be well advanced in the stages of dissolution, some portion of which has been resolved into the end products. Gaseous substances oc- cupy portions of the pulp cavity, which is closed over the entire coronal portion by a layer of dentine, a filling or a plug of foreign substance. These gases are expanded by the elevation of the tem- perature, causing increased pressure upon the remaining vital por- tions of the pulp and intense pain results, which is further aug- mented, many times, by the pulsations of the heart. The pulsating symptom in this instance indicates that quite a portion of the pulp is yet vital. The Treatment for Relief in This Case, Avhich is called closed putrescence, is the removal of the obstruction for the escape of the gas. This involves opening into the pulp chamber through the route of the least obstruction or injury to the tooth. Necrotic portions of the pulp should be removed, disinfectants and anodynes applied and devitalization of the remaining vital portion effected. If Moderately Warm Fluids Cause Pain as well as cold the pulp is in the first stages of passive hyperemia or congestion. This con- dition is generally soon followed by the symptom of being more pain- ful upon the patient's lying down and the throbbing pains setting in, and many times patients will say, "I have the jumping tooth- ache ; " or, " It began last evening about fifteen minutes after I went to bed." Treatment of Passive Hyperemia Pulp for relief is sterilization of immediate surrounding tissue at the tooth's cavity and the ap- plication of sedatives and anodynes. If the pulp can be bled with causing but slight pain it is beneficial ; then proceed to devitalization. The Painting of the Gum with a revulsive is of service, especially if the pericementum is taking on the stages of inflammation indi- cated by slight soreness to percussion. If the Presence of a Foreign Substance in a cavity causes pain it may be an exposed pulp which is not very highly organized, or hyper- sensitive dentine covered with a layer of leathery decay. The Treatment Is the Removal of the offending object and the prevention of its recurrence by temporary or permanent stopping. ALLEVIATION OF DENTAL PAINS 179 Pericemental Diseases Causing Pain have for their most path- ognomonic symptom the soreness to percussion, as shown by gently tapping on the occlusal surface of the tooth with a steel instru- ment. Slight swelling of the pericementum causes the tooth to ap- pear to the patient as much elongated and the patient will generally make such remarks as these, "I have a sore tooth;" "It hurts to close my teeth;" "My tooth is too long," etc. If the pulp is entirely dead, and removed, or there is not a ease of enclosed putrescence, thermal changes will have no effect, except in rare eases warmth applied to the parts will give a slight sense of relief. Treatment for the Relief of Pericemental Pains is the thorough and complete removal of the cause, generally consisting of necrotic pulp tissue, and infectious matter in the pulp chamber. This should be thoroughly removed by mechanical means, assisted by the use of chemicals, and the entire chamber from crown to apex rendered aseptic as soon as possible. If Pus Has Formed at the apical space and flows freely down the root canal temporary relief is most certain to follow if the case is allowed to remain open for twenty-four or forty-eight hours for free drainage, when fiirtlior treatment may be proceeded with. Acute Alveolar Abscesses should be opened externally, as soon as the presence of pus can be diagnosed, this to be done external to the alveolar wall and is least painfully done by freezing the tissues to be punctured. Abscesses Are Assisted to the Surface by painting the mucous membrane over the diseased portion Avith aconite and iodine. In no case should such an abscess, no matter what its size, be lanced through the external surface of the face as all are easily reached from within the mouth. CHAPTER XXXI. PEOPHYLACTIC TREATMENT OF THE MOUTH. The Importance of Prophylactic Treatment early in a series of visits to a dentist and at stated periods thereafter, is second only to the relief of pain, the neglect of which jeopardizes the remain- ing tooth structures, the permanency of attempts to check the ravages of caries and disease, as well as the reputation of the op- erator's skill. Unhygienic Conditions About the Teeth are the sole, immediate and exciting cause of primary or secondary decay of the teeth, and many an operator of exceptional skill as to the making of fillings has failed from a disregard of these conditions. As much of the success of dental operations depends upon the care of the mouth by both dentist and patient in the w^ay of prophylaxis, as upon the skill of the dentist as an operator. The making of a fill- ing is but the repair of an injury and is only a temporary check to the progress of destruction, if the primary cause of dissolution is to remain operative. The Sub-Dental Tissues are also diseased by a lack of prophy- laxis to the extent, many times, of their entire loss, so that the teeth, themselves, are loosened and lost, through a lack of struc- tures to support them, w^hile the teeth so lost are many times yet undecayed, and, in the present-day advancement of dentistry, ex- perienced operators are forced to consign more teeth to the for- ceps from the result of diseased conditions in the tissues surround- ing them than from decay of the teeth, themselves. If this be true the dentist cannot ignore the importance of combating the agencies which bring it about. Preventive Dentistry has the same great field of usefulness as has "preventive medicine" in the practice of medicine and the dentist who masters this phase of the science of dentistry has gone a long way towards success, and many defects in manipulation, ability and ideals in conditions about tooth repair impossible of at- tainment, will stand the test of time if only hygienic conditions are attained and maintained. The Kinds of Deposits Upon the Teeth are generally classified as salivary calculus, serumal calculus, green stain and sordes. The first two named are enemies to tissue about the teeth, while 180 PROPHYLACTIC TREATMENT OF THE MOUTH 181 the last two are responsible for most of the destruction of the hard dental tissues l)y caries. Composition of Salivary Calculus. Mixed saliva contains in man an average of al)out 0.5 per cent solids. The calculus is pre- cipitated into the mouth in a form of a finely divided calco- globulin, Avhich collects in masses upon any stationary object, close to the mouth of the gland ducts. The fresh deposit is very soft and greasy to feel when first deposited, but within twenty- four hours it begins to harden and increases in hardness up to the time of thirty or sixty days, when it has generally attained its full hardness and will break away from the stationary ol)ject in masses shoAving distinct lines of fracture. Lime Salts Held in Solution. Calcium phosphate and magnesium phosphate are held in solution in the saliva, made possible by the presence of a little carbon dioxide. Reasons for Precipitation. When the saliva is discharged into the mouth it is released from the normal blood pressure and some of the carbon dioxide escapes which allows the calcium salts to be precipitated. The lactic acid Avhieh is continually formed in the mouth converts the mucus into a curd in which the calcium salts are entangled to harden into salivary calculus. This process is as- sisted by the presence of the oxygen taken into the mouth with the breath, Avhich facilitates the liberation of the carbon dioxide, in the process of oxidization. Time of Deposits. It Avould seem from the experiments of Dr. Black that the deposits of salivary calculus are paroxysmal and also that these periods of rapid deposit follow the ingestion of heavy meals. He thinks that these periods of excessive deposits come at a time Avhen the blood is overcharged with food pabulum. Kind of Food. It (Iocs not seem from his experiments that the kind of food has very much to do with these deposits. The more easily a food is digested, the more quickly folh)wing the meal will the.se deposits appear. Habits of Patient. Tt Avould seem that the habits of the patient have little to d(j in influencing the amount of these deposits. However those Avho live a life of physical exertion, which favors the using of heavy meals have a greater tendency to deposits of tartar than those Avhoso vocation Avould cause them lo eat lightly. Mouths Most Subject to the Deposit. From our ])reseiit under- standing of this subject it would seem that the mouths most sub- ject to 1h(' dcposil of s;iliv;ii'\' c;ilculus ai'o those individuals. 182 OPERATIVE DENTISTRY First, who from constitutional reasons have a tendency to an abundance of carbon dioxide in the excretions and secretions. This condition may be brought about by great physical or mental activity or v^here the skin, kidneys or lungs, or all, are not per- forming their full functions. These are the principal eliminaters of carbon dioxide. Such individuals are very liable to be troubled with precipitation M^ithin the gland and ducts, through v^hich their secretions are expelled, resulting in cystic, glandular, biliary or renal calculi. Second, those individuals who either occasionally or habitually engorge heavy meals, wherein the quantity of such meals is greater than that needed for growth or maintenance. Third, in mouths wherein the amount of lactic acid is more than normal. Fourtli, in the mouths of public speakers and mouth breathers, whether awake or during sleep. The great amount of oxygen com- ing in contact with the saliva assists in the rapid liberation of the carbon dioxide and consequent rapid precipitation of the calcium salts. Prevention of Salivary Deposits. It would seem that salivary deposits can largely be prevented by stimulating the circulation; stimulating the elimination of carbon dioxide from the body; checking mouth breathing as much as possible, correcting over- acidity of the mouth, limiting the amount of food taken into the stomach at each meal by more nearly equalizing the three daily meals to the needs of the body. Also by so highly polishing the e^urfaces of the teeth upon which the deposit is precipitated, as to facilitate the mechanical removal of the fresh deposits. Last but not least, so instructing the patients in the mechanical features of the care of their teeth that insofar as possible all fresh deposits are removed before hardening takes place. Serumal Calculus is a calcic precipitate from the blood. The salts in solution in the blood as well as the stability of suspension depends materially upon the presence of a normal amount of car- bon dioxide. Serumal Calculus Is Deposited beneath the gum tissue wherein there is a passive hyperemic condition or congestion. Here we have excessive tissue waste, lessened alkalinity of the blood, a lib- eration of the carbon dioxide and consequent precipitation of the inorganic salts. By the recession of the gum after the formation PROPHYLACTIC TREATMENT OF THE MOUTH 183 of the serumal form of calculus, it may be exposed to view, or mixed Avith the mass of salivary calculus. Serumal Calculus in Appearance is of a much darker color than salivary of a harder constituency, and generally adheres to the surface of the tooth more tenaciously. Serumal Calculus Is Also Found on unexposed portions of roots of teeth Avhicli approximate inflammatory exudates, or, are bathed in escaping blood plasma associated with chronic conditions of the apical space. It also appears in other portions of the body as about the joints subjected to chronic inflammations as well as in the glands continually gorged with blood. The Bulk of Serumal Calculus is comparatively small, owing to its formation in restricted spaces and is generally found in small nodules, narroAv bands and thin scales, not always easy of detec- tion or removal. Stains Upon the Teeth are of varying degrees of shade in several colors and from co.smetic reasons stand for immediate removal when detected. However the green stain found upon teeth is so closely connected with the first stages of caries on surfaces so af- fected that it deserves special consideration. Green Stain Is Generally Confined to the labial surfaces and particularly the gingival third of the anterior teeth. It is most frequently found upon the teeth of children and may be seen either upon the temporary or permanent teeth. When it persists for a considerable time upon these surfaces of the permanent teeth the enamel will be found to be etched by a dissolution of the cemental substance evidenced by the whitened surface. The Color Is Due to the bacteria present. The Injury to Tooth Substance is due to the acid which these bacteria produce. The Reason for Their Presence is the favora])le place for lodg- ment affoi'ded by the pei'sistence of the cuticula dentis. Sordes Consists of a mixture of food, epithelial matter and micro-organisms collected upon the teeth. Neglect in the Removal of Sordes results in tooth caries, partic- ularly in localities habitually so unclean. The Removal of Salivary Calculus is accomplished by two prin- cipal plans, the push-cut method and the draw-cut method, each with its advantages. By the Push-Cut Method the blade of the scaler, which has a blunt chisel edge, is forced between the calculus and enamel trav- 184 OPERATIVE DENTISTRY eling in the direction of the root. In its use the principal danger is the slipping of the instrument to the gum tissue beyond and this accident should be well guarded against by first securing a pos- itive and sufficient hand rest. By the Pull-Cut Method the blade of the scaler, which has a hoe point of about twenty-eight degrees, is first passed under the free margin of the gum, its point engaged on the ledge of the calculus and its removal accomplished by a pulling force applied toward the crown of the tooth, or in a plane parallel vvdth the long axis of the tooth. Care should be taken in passing the instrument under the free margin not to lacerate the gums. Pen grasp should be used and a secure hand rest obtained before making an effort to remove the deposit. The First Teeth to Be Scaled is not important, yet if attention is first directed to the lingual surfaces of the lower incisors, we are able to create an impression upon our patients of the impor- tance of the work in hand. It is here we generally find the heavi- est deposits and by removing these first, and allowing them to fall in the mouth the patient is fully awakened to the need of the service being rendered. The same impressions never seem possible if the removal of the larger masses is left until the last. The Proximal Surfaces Are Best Scaled with the pruning hook, draw-cut scaler or the straight push-cut having a very thin blade and about a twenty-three degree bevel. These proximal surfaces will need such attention more from the deposit of serumal calculus than from the salivary variety, which is only present in the proximal surfaces after gum recession. The Removal of Serumal Calculus is much more difficult than salivary, as all of the work is done under the cover of the gum. which requires delicacy of touch and the highest degree of digital skill. Calculus Must Be Distinguished From Cementum, bone and soft tissues, simply by the sensation of touch conveyed through contact of the instrument with the structures in question. The Surface of Eoots, where the attachment of the perice- mentum has been lost, must be carefully examined and the re- moval of all calculus accomplished, and the root or roots thor- oughly polished, as the gum will not regain health where particles of the deposit remain. Several sittings are often necessary to ac- complish satisfactory results. Pyorrhea Alveolaris. The desire to keep this book within eer- PROPHYLACTIC TREATMENT OF THE MOUTH 185 tain limitations prevents the consideration of pyorrhea in its treat- ment. However the foregoing procedure will go far towards the prevention and cure of pyorrhea alveolaris. In fact thorough prophylaxis is the prime essential in the treatment of that disease. The Removal of Green Stain is principally accomplished by the application of some abradent, as pumice stone, with a revolving brush in the dental engine. This also polishes the croAvns of the teeth, removing the small particles of calculus still adhering to them after scaling. Hydrogen dioxide (HoO,) added to the powdered pumice in place of water Avill assist in removing the stains and particularly green stain, of which it is a partial solvent. Following the use of pumice the gums should be thoroughly syringed with water to re- move any trace of tlie pumice, which is insolul)le in the mouth and should not be left around the free margins of the gums. A Clean New Brush Wheel should be used and a fresh mix of the powder made for each patient as a means of preventing the transmission of disease as well as from a standpoint of cleanliness. As well might our patients be asked to all use the same toothbrush^ a thing not thought of, even by members of the same family. The Removal of Sordes is a matter which must be left to the ef- forts of the patients. Its accumulation about favorable portions of the teeth and mouth is but the matter of a night or a day arid upon its speedy and frequent removal depends the salvage of the teeth from the ravages of caries. The Toothbrush is the one great cleansing agent and nine-tenths of the removal of sordes is accomplished purely by mechanical ab- rasion through the movements of the bristles of the brush over the surface of the teeth. The movements of the bristles should be not only crosswise to the long axis of the teeth, but also from root to crown and vice versa, that the travel of the bristles nmy parallel the gingival, enter the embrasures and traverse the grooves and fissures. Hydrogen Dioxide Is the Only Agent Avhich can be used in the moutli ill sufficient strength to dissolve sordes and not injure either the hard or soft oral tissues. This may be used either upon the brush or as a mouth Avash. The dissolution of sordes is accom- plished by oxidation. The Massage of the Gums is advised to i-eiiiove all nnsolidified calculu.s, food particles and other foreign substances from beneath the free margins of the gums as this appears to be the only satis- 186 OPERATIVE DENTISTRY factory method of cleansing these spaces. The massage is also most beneficial to the gums. It stimulates the circulation, retards tissue waste and lessens the deposit of serumal calculus, and in ad- dition forces away that which has been precipitated before it has an opportunity to solidify. Instructions to Patients as to the care of their teeth is an all- important duty of the dentist, not only from the standpoint of what is best for the patient, but much of the dentist's reputation as an operator depends upon the subsequent care given the teeth by the owner following the making of fillings, for upon their en- vironment depends their permanency. Comparatively few indi- viduals know how to properly care for the mouth and many will insist to their dentist that they are most careful of their oral hab- its when upon examination, the dentist finds surfaces which appear never to have been cared for in the least. They have failed to reach these surfaces with their brush. The Technic of Proper Brushing should be thoroughly ex- plained, with special reference to reaching the surface which they seem to be neglecting. Instruct them as to the massage of the gums with the finger tips, rubbing not only crosswise but also from root to crown, assuring them. that if the gums bleed easily it is all the more essential that they repeat the operation and that finally they will regain their normal health and then they will not bleed under the treatment advised. The Use of Floss Silk for passing through the proximal spaces to clean contacting surfaces by wiping off the embrasures and reaching points inaccessible to the brush, should be demonstrated to the patient. Care should be taken not to snap the thread past contact points as it may lacerate the gums. Toothpicks have no place in the care of the teeth and should be prohibited by law, especially those of soft wood so commonly found on the market and at public eating houses. Their square corners and slivered ends irritate the gums, causing" their disease and recession thereby destroying the natural protection to the most vulnerable portions of the teeth. CHAPTER XXXII. EXCLUSION OF MOISTURE The Exclusion of Moisture from most operations upon the teeth is essential to the successful manipulation of most filling materials, the sterilization of tooth structures and the prevention of infec- tion, the cleanliness of cavity walls and margins, that a perfect view of the cavity may be obtained, that the extent of decalcifica- tion may be observed, to diminish the pain of operations on living dentine and to protect the soft tissues from injury in the use of caustic drugs, as well as to save time of both patient and operator. The Methods of Securing Dryness during operations are here given. The Rubber Dam, invented and given to the dental profession in 1864 by Dr. Sanford C. Barnum, of New York City, is widely used. Absorbents, as napkins, cotton rolls and pads packed about the teeth and near the mouths of ducts, assisted by specially con- structed clamps upon the teeth are also used. Dryness is also se- cured by the )'.se of the saliva ejector whereby the mouth is con- tinually drained of the secretions. The Objections to the Use of the Rubber Dam are entirely on the part of the patient and can generally be traced to awkward and unskilled handling on the part of the operator. Every oper- ator should become dextrous with each method, that he may em- ploy the one most expedient in every case, using the one least objectionable to the patient. The Neglect of Dryness in dental operations is to invite disaster in root canal treatment, as Avell as short life to all fillings so placed, and the operator who makes it a practice to neglect this essential, obtains only a ^lartial success in that which he attempts. So Important Is Dryness that a patient should be warned that a certain operation, where moisture has been allowed to flood the field, is short-lived at best and is liable to failure from this cause. Such conditions seldom arise but are occasionally met with, due to location and extent of decay and also from the fact that there are some patients who are nauseated by the presence of the dam or absoj'bents about all but the most anterior teeth. All Filling Materials are better manipulated under dry condi- tions at some stage of the operation, porcelain being the only one demanding moist conditions at any stage of the process. This 187 188 OPERATIVE DENTISTRY moisture in porcelain filling is only required to preserve the shade of the tooth substance to be imitated in the fused filling. Those to Which Dryness Is Most Essential are silicate, cohesive gold, cement amalgam and gutta-percha, named in the order of the importance of the demands. It is true that all of these excepting silicate may be successfully manipulated under moist conditions, but the effort is greater and the certainty of success is materially decreased. The Exclusion of Moisture for Sterilization and the prevention of infection is imperative in the last stages of cavity preparation, as it is physically impossible to properly perform the toilet of the cavity and properly sterilize the same when flooded or even under moist conditions. The Proper Treatment of Pulp Canals cannot be accomplished when flooded by the oral fluids to say nothing of the introduction of a permanent root filling. The saliva is at all times impregnated with various forms of bacteria. Its presence invites failure by pre- venting sterilization of canals already septic and permitting the re-infection of those already sterile. Cavity Walls, and particularly the beveled margins, must be freshly cut and planed after being moistened before the introduc- tion of a filling, as this is the only means of having an absolutely clean surface. We may resort to absorbing and evaporating the moisture from the walls and margins of a cavity, but there will invariably be left a residue or film upon the surface which is solu- ble in the oral fluids. No amount of pressure in introducing the filling, be it rubber, amalgam or cohesive gold, will displace the moisture absorbed by the cavity surfaces, hence we have this layer of moisture or sediment intervening the filling and cavity. This will be exchanged in course of time for that upon the outside carrying with it bacteria and the products of fermentation or lac- tic acid and secondary caries is the result. Bacteria, which are the active agents of caries, will go where moisture Avill not, and the lactic acid which they secrete will go where the space is too small for the bacteria. It will therefore be readily seen that a moist sur- face or one coated with a residue of an evaporated mixture, whether medicine or saliva, intervening between a filling and a cavity wall, becomes a large passage way for the greatest enemy to tooth substance — lactic acid. A Better View of the Cavity Is Obtained When Dry, as its out- lines become more distinct and its size and shape better defined. EXCLUSION OP MOISTURE 189 No mechanic ever thinks of trying to accomplish his best work with the object submerged in moistui-e. The rays of light are broken, objects are distorted and distances misjudged. The dentist ■who does not effectually exclude the moisture from the immediate neighborhood of a cavity will catch only a glimpse now and then of portions of a cavity, this being particularly true of the gingival wall, except in cases of gum recession. The Extent of Decalcification of both dentine and enamel is di- agnosed only when dryness is obtained to bring out the colors and shades of each incident to these conditions. It is impossible to make proper cavity extension until the cavity has been made dry and so maintained for some time, as this is often the only means of detecting superficial caries. Semi-decalcified tooth substance, when moist, materially resembles the healthy structures and must be dried to detect its injured condition. The Pain of Cavity Excavation is materially decreased by the extraction of the moisture from the dentine. The protoplasm within the dental tul)ules is the means of transmitting the sensa- tion of pain to the vital pulp. Water is a large constituent of pro- toplasm and the extraction of this moisture through extreme and continued dryness removes the media of sensitiveness. It is there- fore but humane that the cutting of dentine be done with the mois- ture excluded. When Using- Caustic and Concentrated Drugs the moisture should be excluded, that the drug may not be carried away to the injury of adjacent tissues and that the drugs may not be diluted to deti'act from their efficiency in accomplishing that for which they were used. Drugs placed in the cavities of teeth with moist mar- gins even when placed under fillings of rubber, cement or amalgam, will follow the moisture of these margins to join that without and great damage to the surrounding tissues often results from no other cause than a hiok of the exclusion of moisture during the operation. As a Time Saver the exclusion of moisture should not be ovei"- looked. With a dry cavity the continued uninterrupted view per- mits of more continuous woi-k by the dentist. He does not have to wait for the patient to expectorate, make a few remarks and leisurely resume his position in the chaii-, not always in the position desired for operating. The opei-atoi- will also be saved nnich time in dry- ing the cavity after each flooding. All this takes valuable time, much more than is re(|uired tf) adjust a dam. The Rubber Dam is the most (IcpciMhihIc nicans of securing a d?-y 190 OPERATIVE DENTISTRY field for operating and its proper and speedy adjustment should be mastered. It is made in three thicknesses ; heavy, light and medium, the medium being the weight best adapted for all purposes where only one weight is to be kept at hand. The Size and Shape is of little importance so long as it com- pletely covers the mouth after it has been made to isolate the teeth desired, as well as cover the chin and extend to either side of the mouth sufficient for the proper engagement of the holder. This will require a piece from five to six inches square, for all cases back of the six anterior teeth and is most frequently the size used on the anterior teeth. However, some economy of rubber dam may be prac- ticed by cutting these squares in two triangular pieces, each of which will do for a separate case. These are applied with the diagonal of the quadrilateral (hypotenuse) uppermost. The Holes to Receive the Teeth should be of the proper size and smoothly cut, otherwise there is an increased liability of being torn in adjustment. This is best done by the use of the rubber dam punch to be had at dental depots. However, in the absence of this, a very good result is obtained by drawing the rubber tightly over a tapering round handle of an instrument and touching the sharp edge of a knife to the rubber down the side of the handle when a per- fectly round piece will be cut out. The Distance Between the Holes will vary according to the space between the teeth, the height of the festoon of the gum, the weight of the dam and the size of the teeth to be engaged. Generally speak- ing, the holes are cut from two to four millimeters apart in medium dam. The lighter the dam the farther apart should be the holes. The holes are farther spaced with extremely large gum festoons, also when there is a considerable gum recession. If the holes are too close together in above condition the dam may not cover the entire proxi- mal tissues and a leakage may occur, or the gum septa may be un- duly compressed and permanent injury result from strangulation. If the holes are too far apart the rubber will wrinkle and bag at the proximal spaces and seriously hinder operations in these localities. The Location of the Holes in the piece of rubber dam depends upon the location of the tooth to be operated upon and the teeth to be isolated. A beginner will do well to first place the dam over the mouth in the position desired for the outside edges, request the patient to open the mouth and with the finger cause the dam to come in contact with the occlusal surfaces of the teeth it is intended to include and then punch the holes as this trial indicates. By this EXCLUSION OF MOISTURE 191 method the operator will soon become familiar with the location in each case. The Number of Teeth Isolated depends upon the location and the operation to be performed. For the short treatment cases, sometimes the placing of one or two teeth under the dam will suffice, but in most cases where fillings are to be made and polished, from five to eight teeth should be included that a good view of the field of opera- tion may be had and the loose folds of dam carried farther away to avoid them catching in the revolving points of the engine. With Anterior Teeth the first bicuspid tooth of either side should be included, as the cuspid from its conical shape is many times unsafe for a final ligature. With Bicuspids and Molars as the objective teeth in an opera- tion, there should also be included the teeth anterior to the median line. The Clamp should be placed on the tooth back of the one to be operated upon, excepting in mesial cavities in second molars when the clamp may be placed on the second molar, thereby avoiding the clamping of the third molar except when absolutely necessary, as with distal cavities in second molars. The Placing' of the Dam requires the freedom of both hands of the operator, and the aid of an assistant is of value. The necks of the teeth upon which the rubber dam is to be placed should be cleansed of all calculus and sordes and fllooded with a jet of water from the syringe. If the gums show hypersensitiveness they should be bathed in a solution of novocain, restricting its use to the gingival borders. Waxed silk should be passed through the proximal spaces to clean them and prove access for the rubber. If sharp margins of cavities cut the silk these should be dulled by passing a thin ribbon saw through the proximal space or, with the chisel, carry the margin sufficiently into the embrasure to give access. AVhen teeth are in close contact so that the silk thread is passed with difficulty, the rubber can be made to pass more readily by the use of soap, which is done by placing the row of holes on the ball of the index finger, occlusal .side up, and rubbing the soaped fingers of the other hand across the holes. The Occlusal Side of the Rubber Dam is that side which is to- war-capping more hazardous and it should be practiced with great care in this location. Again, less risk should be taken in the 206 OPERATIVE DENTISTRY capping of pulps in the anterior portion of the mouth as it is better to remove a number of questionable pulps than to have one die in the tooth with its consequent discoloration. The Length of the Time the pulp has been exposed to the irritat- ing influences is to be taken into account as the shorter the time of exposure, the greater the probabilities of success in capping. The Stage of Hyperemia should be a safe criterion where there are actual pulp complications, as there will be in almost every deep- seated cavity. In active hyperemia, from causes other than bacteria, it is safe to protect the pulp from futui'e irritation and insure its conservation. However, when the symptoms of passive hyperemia have developed it is not safe practice to attempt to restore the pulp to normal and expect permanency. The Symptoms of Active Hyperemia when the pulp demands protection and success may be expected are : First — When the excavated cavity exposed to the air causes a con- tinued pain not of a throbbing nature and the condition is relieved by packing the cavity with dry cotton. Second — When a blast of air from the chip blower causes a quick, sharp, shooting pain which subsides as quickly as it came. TTiird — When the pulp shows the power of accommodation as evi- denced by tolerating a draft of cold air when the same is gradually applied. Fourth — When it is improbable that the pulp has become infected. Pulps Infected With Bacteria should be extirpated as too large a percentage of those exposed and capped die and thereby bring re- proach upon dentistry in general and chagrin to the careful operator. The time was when the profession attempted to conserve all por- tions of the pulp found to be vital, even to amputating the coronal portion and leaving intact the vital stumps. However, this was in the days of imperfect root canal treatment and filling and about as many abscesses followed one kind of treatment as the other. But at the present time the removal of a pulp is attended with such uni- versal success that the capping of exposed pulps, in general, is un- warranted, as most pulps are infected at the time of exposure. Even in the case of an accidental exposure in the preparation of a cavity neither cavity nor instruments are surgically sterile. The General Health of the Patient must be considered when choosing between the conservative or radical treatment of the pulp. With the same conditions presented, the pulps in the teeth of the an- emic patient, those wherein the vital processes are at low ebb, or the PROTECTION OF THE VITAL PULP 207 elimination of the vital ash is imperfect and cell metabolism is defi- cient, protective means of conservation are more imperative, while at the same time less risk should be taken in questionable cases. With Robust and Particularly Plethoric Patients, all inflamma- tory processes run a rapid and riotous course, and when the pulp has taken on any stage of hyperemia changes towards dissolution are of rapid succession. In Deep-Seated Cavities it is not unlikely that the thin layer of the dentine covering the pulp is infected and the pulp should be protected from the invasion by the thorough disinfection of the over- lying dentine by medication, previous to filling as well as placing next to the dentine in question and under the filling a permanent dressing which will exert a mildly antiseptic influence for some time following the operation. The Requirements of the Materials Used in Protective Pro- cedures Are: First — That they shall be poor conductors of heat and cold. Second — That they shall be non-changing in character, both as to consistency and bulk. Tliii'd — That they have no action upon the pulp. Fourtli — That they may be introduced into deep seated cavities without pressure. The Materials Advocated for This Purpose Are Numerous and the market is flooded with preparations of a secret nature which are warranted to save the pulp in almost any stage of dissolution, but the operator who pins his faith to such slipshod methods will sooner or later find that he has been duped and his grief is measured by the extent to which he has employed these cure-all methods. There Are Four Distinct Classifications Avherein success may be expected in methods of pulp protection. The treatment of each class is here given. First Class. In the Progressive Stage of Caries ^\•hcrein Init lit- tle dentine has l)een lost, yet a blast of air from the chip blower causes a fiuick, sharj) pain, passing off as soon as the draft of air is checked, we find the simplest form demanding protective measures. This is the class most often neglected hy the operator and many times irrei)arable injury is done a pulp by placing in such a cavity a filling of high conductivity, such as gold or amalgam. The patient often believes that "cold water leaks in about the filling" and may visit another dentist thinking that he has a poor piece of dentistry, and the patient may be lost to an otherwise good opei'ator, all through the neglect of what may appear to the operator as a trivial matter. 208 OPERATIVE DENTISTRY The Treatment of the First Class is the thorough dismfection and then the application of phenol, full strength, for a few seconds, when the cavity should be dried and it will be found unaffected by the blast of air from the chip blower. The change is brought about by the superficial coagulation of the albumen in the exposed ends of the dental tubuli which renders them non-conductive. Second Class. If, after one or two applications of the phenol as above, the distress from the blast of air is not relieved, or if the pain is continuous while the surface of the cavity is exposed to the air it is probably of the second class as met with in the nearer ap- proaches to the pulp. This class of cases demands a media interven- ing the dentine and the filling. The Treatment in the Second Class is as follows : Moisten the cavity with phenol and evaporate to comparative dryness. Then paint the entire dentinal walls with a cavity varnish composed of copal and gum dammar in alcohol and ether solution. Such a prep- aration can be had at the dental depots or it can be prepared by the druggist. This should be thin and spread evenly, applying one, two or three coats and drying with a draft of air from the chip blower after each coat. When the varnish is entirely hardened the filling may be placed. Third Class. In the deep-seated stage of caries, where large quantities of dentine have been lost, even though the pulps may seem to be protected by secondary dentine that is much retracted, it is not safe to place a metal filling directly on the overlying den- tine. The lost tooth structure should in a measure be replaced with a material which is not a better conductor of thermal changes than dentine. This should be neutral as far as irritating properties are concerned, non-changing and should resist the force necessary to properly introduce the intended filling. The Treatment in the Third Class is as follows : Phenolize and dry. Varnish with the above cavity varnish and dry. Flow over the dentine, covering most if not all of the axial or pulpal wall, or both, according to the class of cavity being treated, a thin layer of oxyphosphate of zinc cement, being careful not to include thereunder any air bubbles; also apply without pressure. Then allow this to set to complete hardness, when the filling may be completed. In the three classes given above it will be noted that coagulation of the protoplasm in the exposed ends of the tubuli was the first step. This is good practice from the fact that this layer of coagulum is the least irritant to the remaining protoplasm of anything of which we have knowledge. Phenol is very limited in the extent of its action PROTECTION' OF THE VITAL PULP 209 and this layer of coagulation is very thin. Again, with this third class, it will be noted that in addition to the nse of the phenol the cavity is given a coat of varnish before applying the oxyphosphate of zinc cement. This procedure is to prevent the irritating effects of the phosphoric acid, particularly while the cement is setting. Again, should the zinc contain any impurities their action on the pulp is prevented. One of the impurities of zinc is arsenic and some cements are thought to contain traces of this devitalizing agent. The cavity varnish given above is quite impervious to this element when it has been thoroughly hardened, a fact which should not ])e over- looked when it is desired to prevent the action of arsenic trioxide in a particular direction in a dental wall. Fourth Class. In deep-seated cavities where there is a slight pulp complication from thermal shock and where the thin overlying layer of dentine is probably infected to some depth and more deeply affected in the process of caries, the dentine should be subjected to quite a continued disinfecting process and a portion of the lost den- tine restored with a non-conducting material to shield the pulp from sudden thermal changes. The Treatment in the Fourth Class of cases is as follows: The cavity should be flooded with a non-irritating antiseptic, as campho- phenique, pure beeehwood creosote or oil of cloves. If sealed in the cavity for twenty-four hours the result will l)e much better. The cavity should be then wiped dry with absorbent cotton and a thin paste of a cement containing sulphate of zinc spread over the den- tine overlying the pulp. This paste should be tliiii enough to flow to position when coaxed with a small in.strument, yet thick enough to prevent its spreading to surfaces not needed. Over this spread a layer of oxyphosphate of zinc cement and jilldu this to set hard be- fore completing the filling. In very questionable cases, the eiitire cavity may be completed with the cement and the patient dismissed for six months, at the end of which time, if the pulp is found to be normal, a portion of the ce- ment may be removed and replaced with a more permanent ma- terial. Pulp Preservers and So-Called Mummifiers should be avoided. Even their name is misleading and such i)]'epai-ations arc used with- out permanent success in the majoi-ity of ca.ses. Their use simply proclaims their users as un.skilled laggards who will accept an un- certainty to avoid a little honest labor in pulp extirpation and root filling. The entire procedure is diabolical and cannot be condemned 210 OPERATIVE DENTISTRY in too severe terms as a retrogression in dentistry, unskilled in prin- ciple and unwarranted in practice. Gutta-Percha as a Protecting Covering is not a success from the fact of its great range of contraction and expansion under varying thermal changes. When enclosed under a perfectly tight and un- yielding filling, as all fillings should be, the change in bulk must have a piston-like effect upon the contents of the dental tubuli result- ing in continued irritation. CHAPTER XXXV. PULP DEVITALIZATION AND REMOVAL. The Reason for Devitalization and Removal of a pulp is its pres- ent unhealthy condition or when its future health is in danger, on account of environment in the way of dental operations. There Are Two General Causes of diseased pulps. First. That succession of tissue changes which has its origin in active hyperemia and its end in death due to the presence of bacteria or their products — inflammation. Second. Reparative congestion, due to traumatic injury, abnor- mal thermal stimuli, lack of normal thermal stimuli and peripheral nerve irritation. Bacteria and Their Products may enter the pulp tissue either through a loss of its normal covering, the dentine, as in the case of deep-seated caries, or through the general circulation by way of the apical foramen, as in pyorrhea alveolaris, or in other pus conditions in close proximity to the pulp vessels. We have no means of know- ing that a pulp thus invaded has recovered, while we have complete proof of their subsequent death from this cause, hence devitaliza- tion is indicated as soon as diagnosis is clear. The Removal of the Cause in reparative congestion of the pulp will genei-ally suffice to save the pulp from further destruction pro- vided the intervention is in the stage of active hyperemia. The Traumatic Injuries most common in the production of pulp congestion are blows upon the teeth either through accident or ex- cessive malleting in dental operations; rapid movement by the ortho- dontist; abnormal stress in occlusion or articulation; malocclusion and abnormal movement of the tooth in its alveolus made possible by the loss of supporting structures. Abnormal Thermal Stimuli is a most potent factor in producing pulp congestion. The pulp is particularly and peculiarly susceptible to thermal changes and this idiosyncrasy is very rapidly magnified as the stages of congestion progress. The Reason for Abnormal Thermal Changes reaching the pulp is the loss of its natui'al covering, the dentiiie and enamel, through caries, erosion, abrasion oi" dental operations as well as the denuding of the root by a recession or loss of the sub-gingival structures. Lack of Normal Thermal Stimuli will induce a stagnated cii-cu- lation with a sequela of degtinerative changes within the pulp tissues, 211 212 OPERATIVE DENTISTRY resulting, many times, in the death of that organ. While the pulp is profoundly affected by abnormal exposure to heat and cold it is eminently essential to its normal physiological existence that it re- ceive the stimulating effects of the ranges of temperature usually found in food and drink while covered with the entire tooth. Peripheral Nerve Irritation may bring about reparative conges- tion within the pulp causing excessive tissue waste and a precipita- tion of lime salts within the pulp. There are two classes of these deposits, known as calcific degeneration and pulp nodules, the latter being the sequela of peripheral irritation, while calcific degeneration is the result of little local passive hyperemias with its cause related to abnormal thermal changes. The Irritation May Be in the terniinal fibers of the nerves A^-ithin the pulp where the nodules are found, or in an approximating toothy or in a tooth in the same lateral half of the jaw or face. Cases are reported where it is evident that the cause is even more remote than has been stated, it being a local expression of a general neurotic con- dition. The Requirements of a Devitalizing Agent are : First. That the present and future health of adjacent tissues be maintained. Second. That it act painlessly. TMrd. That the dentine is not discolored. Fourtli. That devitalization be accomplished promptly, resulting in a saving of time to both the patient and operator. The Methods of Pulp Devitalization practiced at this time are two: Surgical amputation while anesthetized and poisoning by the application of arsenic trioxide. To Determine the Method to employ in any given case requires an understanding of the pulp presented, its immediate surroundings, and results sought. Also the time at the disposal of patient and operator. While each of the two methods has its advantages, either can be so used as to meet the requirements of a satisfactory means of devitalization. Anesthetization of the Pulp is accomplished by forcing into the pulp either a solution of cocaine hydrochloride or novocain popularly known as ''pressure anesthesia." Anesthetization Is Indicated: First. When it is desired to remove a normal pulp. Second. When slight exposure of the pulp exists which has not yet reached the stage of passive hyperemia. PULP DEVITALIZATION AND REMOVAL 213 Third. Pulps whose circulatory system is active, but whose ner- vous system is either deficient in development or is in the stages of neuroparalysis. Access to the tooth is a factor to be considered and will result in the more frequent use of this method with the anterior teeth. The possibility of securing a sterile field of operation must be considered as an advantage. The Technic of the Operation wliere a cavity exists is as follows : Apply the rubber dam. Excavate the affected dentine. Sterilize the remaining cavity. Place in the cavity over the pulp a small pellet of cotton saturated Avith either cocaine or novocain. Apply over this a piece of unvulcanized rubber which will approximately fill the cavity and with l)lunt instruments, as amalgam packers, gently force the mass in the direction of the pulp. It is essential that the rubber first come into contact with the cavity margins at all points, or the fluid will not be confined and its escape renders the attempt a fail- ure. If the first pressure of the confined solution upon the pulp causes pain the operator should stop increasing the pressure, but hold the advantage gained by not releasing the pressure already ap- plied, when, after Avaiting a minute or two, the pressure may be in- creased and finally the rubber can be kneaded into the cavity with considerable force. Sometimes one application thus made will com- pletely anesthetize a pulp. However, other eases Avill require two or more applications. BetAveen such applications the dentine should be removed from over the pulp to complete exposure Avhere this can be done Avithout undue pain to the patient. When, after tAvo or three attempts of the above method there seems to be no effect obtained, it is generally best for both patient and oper- ator to i-esort to the application of arsenic, unless the case is suited to favor the use of the high pressure syringe. The High Pressure Syringe is of service Avhei-e no exposure ex- ists, and Avhere the necessary puncture for the introduction of the gyringe point can be included in the filling, or Avhere the croAAai is to give place to an artificial one as an abutment for a bridge. The method has to recommend it speed, a certainty of preserving the color and is generally accomyilishod Avith little ov no pnin to the pn- tient. The Technic in Its Use. To Ihc prescription given for the open cavity add fift('(!n drojjs of distilled water and load the syringe, see- ing that all joints are screwed uj) tight. Select a point of direct access either on the dentinal walls or it may be on Ihc cxtei-nal onaiiK'l surface, preferably in the gingival third of the toolh. and drill a hole directly towards the f)iilp one millimeter in depth and as much 214 OPERATIVE DENTISTRY farther as possible without causing the patient pain. The drill used should be smaller than the syringe point that a close fit to the hole may be secured. Syringes are generally constructed so that a drill made by flattening a No. 1-2 round bur will make a proper sized hole. The syringe is then applied to the opening with some pressure and its contents forced into the dentine. It is essential that the solution be perfectly imprisoned as it re- quires high pressure to force the anesthetic through the tubuli. Af- ter holding the solution at high pressure in contact with the dentine for one or two minutes it should be removed and the drill applied to the hole to test its sensitiveness. If desensitized the hole should be carried close to the pulp but not so far as to enter the chamber. The syringe should be again applied and with great care, as sudden force may cause pain by too rapid pressure upon the pulp. Great Care Should Be Exercised when the pulp has been thus nearly or quite exposed not to force into the pulp any considerable amount of the anesthetic as it is carried or forced beyond the apical foramen, from which no good can result and harm may, particularly if the contents of an infected pulp are forced through to the tissues of the pericementum. Pulp Extirpation by Hypodermic Injection. Pulps may be re- moved very quickly and without pain by injecting the solution of novocain as given for use in extracting teeth in Chapter XLI. If Correctly Done the Pulp May Be Removed or the tooth ex- tracted painlessly. Extreme care as to asepsis must be given. This danger of infection makes this method unsuited for general use, but applicable to cases where haste is imperative or where trouble is ex- perienced in the use of pressure anesthesia or arsenic devitalization. The Removal of an Anesthetized Pulp is accomplished by gain- ing access to the pulp chamber from a position which will admit of direct or nearly direct approach to each of the pulp canals, and mak- ing the opening large enough to admit light enough to see either by direct vision or the image in the mirror, the entire floor of the cham- ber. First, a smooth sterile broach is passed down each canal to the apex of the root, to test the completeness of the anesthetization. If no sensation is found the barbed broach is then passed to the apex, preferably an extra fine size. This should be twisted to the right about one complete turn and then gently drawn from the cavity, which should result in the amputation and removal of the entire pulp. This accomplished, the sides of the canal should be rasped with a barbed broach of a larger size to remove any shreds which may adhere to the sides of the canals. PULP DEVITALIZATION AND REMOVAL 215 To Check Hemorrhag-e, should that ensue, Avash the chamber and canals with cold water, dry as quickly as possible, flood cavity with a drop of adrenalin chloride and apply a plug of dental rubber, pressing this into the cavity and holding it for a few minutes. Re- move the rul)ber and wash again with cold water. If hemorrhage continues repeat holding the adrenalin confined longer than before and applying a little more force. Care should be used in this pro- cedure as a sore tooth will result when the method has been used too vigorously. Again thoroughly bathe the canals with cold water or alcohol and dry. Discoloration Results from allowing any blood to remain in con- tact with the dentine, even though it be only from one treatment to another as the iron of the hemoglobin is absorbed or forced into the tubuli resulting in permanent discoloration. The use of liydrogen dioxide is not good practice until the blood has been washed from the dentinal walls as it oxidizes the iron of the hemoglobin and dis- coloration Avill result. Post-Extirpation Pains may l)e prevented by pumping into the canals phenol with a smooth broach continuing this until the nerve stump at the foramen is bathed with this agent. This also has the effect of coagulating the mouths of the dental tubuli, resulting in sealing them to agents which may cause discoloration. It Is the Best Practice to Dress the Canal or Canals for a few days with a stimulating anodyne which is at least mildly antiseptic, as the anesthetizing of the pulp has ])ro])al)ly so much affected the tissues in the apical space that there is nothing to guide us in prop- erly filling the pulp canals. Immediate Canal Filling in these cases is sometimes practiced where lack of time demands a hurried completion of the case and is quite successfully accomplished where all is just right. But so many times ideal conditions for canal filling are not obtainable that its universal practice is condemned. However, if there is to be im- mediate canal filling the pulp canals should be l)athed with water and dried with warm air, flooded with phenol and again dried, this time with the aid of absolute alcohol, when the canal filling may be introduced as outlined in the chapter on "The Filling of Pulp Canals." Devitalization With Arsenic Trioxide is llic mctliod in most fre- quent use and although not always to be i)referred to ancstliotiza- tion. it may })c us('lie(l not only upvvai'd but backward, rememberinf? that the apices of the two roots are nol directly un- 260 OPERATIVE DENTISTRY Fig. 133. — Types of superior third molars. The first row shows the buccal, the second row the lingual, the third row the mesial, and the fourth row the distal surface. (From Winter's Exo- dontia.) EXTRACTION OF PERMANENT TEETH 261 I''iK. 134. — Types of al)norni;il siiiierior iliii rooted teeth, the Ihirrl row shows ticlh with root> Till- lust anil second rows show four- fuse*], the fourth row shows teeth . ...^. , .... .,,..., ,.,„ .-,■■. ,vv7. iiuiii Willi loois iiiai are lused, me lourtn row snows feetli hayini? crowns with a smRle cone and only one root, and the liflh row shows teeth having roots in which there is great variation in form. (I'roiii Winter's J;xodonlia.; 262 OPERATIVE DENTISTRY der the crown but posterior to it, giving the root a curve backward. A common error is made when the force of traction is applied at a right angle to the plane of occlusion. There should be no rotation. I'or as these are double-rooted teeth rotation accomplishes nothing except to increase the pain by alternately increasing and releasing the pressure upon the highly vascular and sensitive peridental membrane. Pressure should be directly buccal. Although it may seem t'o the operator that the process is thinner upon the lingual aspect of the inferior maxillffi, this is generally not the case. Yet, as with all lower teeth, a malocclusion or an irregularity may make the process thicker on the buccal surface. Superior Third Molars. Rotation is applied in but one direction, one that would roll the top of the hand towards the median line. Pressure should be buccal and at the same time distal. Being the Fig. ISS.^One of the many abnormal conditions found when extracting upper second and third molars. In this case the first molar was the only one which had erupted. The patient was about forty years of age. A very severe abscess appeared beneath the tissues overlying the second and third molars. An incision revealed the condition. The photograph shows the result of extracting, all three coming out attached. last tooth in the mouth and seated at the angle of the jaw, it is not very firmly supported by the process, which in some cases is almost entirely wanting on the posterior buccal corner. Inferior Third Molars. Traction should not be only upward, but backward, which can be accomplished after grasping the tooth with the beaks of the forceps, and allowing the handle to lie across and near the anterior, inferior teeth. As the traction is applied the handles are raised and have an amount of spring which will tilt the crown backwards in proportion to the distance the anterior teeth are separated by the opening of the mouth. Here we have the only tooth in which there is an almost universal exception to the direction in which the pressure should be applied to be in the line of the least resistance. In the case of the third inferior molar, it is to the lingual. The coronoid process of the inferior maxillee comes down EXTRACTION OF PERMANENT TEETH 263 endino: in the external oblique line which is an eminence and ma- terially thickens the jawbone just buccal to the third molars. It must also be remembered that there is little of the alveolar process formed around the third molar, seldom more than that por- Fig. 136. — Position for extracting right upper thinl molars. tion which buihls in a round tho neck to insure its i-etentioii. Thci'e- forc when th(! tooth is broken off it at once becomes a very difficult task to remove the i"cmainiii is a powerful one as the bones and muscles of the arm and body are in a position to exert a great amount of force while giving the tooth buccal pressure and rotation with the top of the forceps moving toward the median line in the rotary motion and the handles of the forceps, are pushed out and back. While this may look awkward in the photograph many of my students who have tried it have been very much pleased with the results. Injury in this way at this particular point may be far-reaching- in its effect, as fractures are most likely to follow weakened portions; EXTRACTION OF PERMAXEXT TEETH 265 Fig. 138. — Types of inferior third molars, the lingual, the third row the mesial, and the fourth row the distal surface incomplete and malformed molar roots. The first row shows the buccal, the second row The fifth row shows (From Winter's Exodontia.) 266 OPERATIVE DENTISTRY Fig. 139. — Elevator beaked forceps for extracting third molars. Fig. 140. — Position for extracting right inferior third molars. EXTRACTION OF PERMANENT TEETH 267 of the bone, and in this case they overlie the inferior dental nerve and vessels. Hemorrhage Following Extraction. Excessive hemori'hatje fre- quently follows tooth extraction, and is more frequently met with in cases after extractino^ first or second lower molars. Fig. 141. — Position for extracting left inferior third molars. In Mild Cases a tamijon of cotton salui-aled willi liydroj^cii di- oxide or adrenalin chloride crowded well to the bottom of the alveolus from wliif'li tlif licmorrhaf^e is cominj? will usually be sufficient. In Severe Cases a tampon made of the sci-apings ol" oak-tanned 268 OPERATIVE' DENTISTRY sole leather will prove effective. T*he scrapings are made by the den- tist from a piece of sole leather by scraping shreds from the edge. These should be previously prepared and ready for an emergency. They should be placed in a large-mouthed bottle and sterilized by dry heat and securely corked. Method of Applying". When case pi-esents, there should be three pellets made, small, medium and large about the size of the al- veolus. These should be introduced quickly one after the other and pressed to position and held there for some minutes with the ball of the finger. The leather scrapings will swell and effectually plug the alveolus. Also the tannin in the leather liberates the fibrinogen and an im- pei-vious clot is formed. Within twenty-four hours the last applied pellet of scrapings will have been raised out of the socket and the next two will soon follow. This is recommended as a method that has never failed in a long list of desperate cases but should not be resorted to except as an ex- treme measure as great soreness frequently follows the treatment due to the interference with the circulation for some considerable distance about the bleeding alveolus. Hypodermic Injections of Adrenalin Chloride for hemorrhage following extraction is good practice. Load the syringe part full with Ringer's solution to which has been added five drops of ad- renalin chloride. Introduce the needle, which should be long and large, into the apical space and inject a few drops. Repeat two or three times if necessary. Capillary Hemorrhage. If the hemorrhage is capillary, inject into the tissues from which the blood is coming. CHAPTER XL. EXTRACTION OF TEMPORARY TEETH. The extraction of temporary teeth at the proper time and under normal conditions is not a difficult operation, owing to the amount of phj^siological resorption of both alveolar process and roots of the teeth. The Most Important Thing Connected With Their Extraction is an accurate knowledge of the order in which nature proposes to re- place them with the permanent set. Results From a Disregard of This Order. The premature or tardy extraction of temporary teeth has more to do with irregular and unsightly permanent teeth than any other one cause. There- fore it is w^ell to make a careful study of the order in wdiich the tem- porary set is replaced. Time of Eruption of the First Permanent Molar. The first molar teeth make their appearance at between five and six years of age. They are generally supposed by the laity to be deciduous and are frequently allowed to decay beyond remedy before the mistake is discovered. They are then extracted without much thought, either through necessity or from being mistaken for temporary teeth by the physician on account of the youth of the patient. The parents are wonderfully surprised to find such enormous i-oots on Avhat they believe to be a temporary tooth. Duty of Dentist in This Matter. The practitioner of dentistry has a very important duty to perform in insisting upon the reten- tion of this tooth; for through its loss a decided derangement of the permanent set results and lack of proper development of the jaw is Olicoiii';if;('(l. First Permanent Tooth to Erupt. Fig. 142 is a side view of child's jaw at about the sixth year. No. 1 in the top row is the fii'st molar, aiid is a part of the permanent set, the second and third molai-s coming in after the temporary set has been entirely replaced by i)crmanent teeth. Reasons for a Permanent Tooth at This Time. Nature in giving us tiiis pci-mauc'iit tooth at tliis pjii-ticuhir time and located at this particular place, seems to desire to put in a permanent fixture as a dividing line in the jaw between the teeth which are lo be replaced, an«1 lliosc which arc not. as shown by lijie A- A. Evil Effects of Early Extraction. // /;,// /'roper F.xirarlion and 269 270 OPERATIVE DENTISTRY Coacliing Into Place of the various teeth in their proper order the position of this line A-A, which bisects the jaw just at the mesial of the first permanent molar, is not allowed to move anteriorly, there is left just the proper space which the permanent teeth will occupy- when they replace the temporary set, provided the jaw development is not interfered with, but if by the premature extraction of the sec- ond temporary molar, this first permanent molar is allowed to tip forward, thereby moving line A-A anteriorly, we have encroached just that much upon the space required by the permanent teeth. The Irregularity Resulting From Such a Mistake will probably be shown in the cuspid as this is the last of the temporary set to be 3-3-6-4 -5 i-3-!^-— 4— 5 Fig. 142. — Represents the complete set of deciduous teeth with the first permanent molar added. Lower row of figures represents the order the deciduou steeth generally erutp. Upper row of figures represents the order of the replacement by the permanent set. replaced. (See Fig. 143.) Again, if the first permanent molar is extracted before the temporary teeth have been replaced, nature seems to realize that further development of the jaw on this side is not necessary, and the jaw- — be it lower or upper — will generally lack in length to correspond with its antagonist, the width of the tooth extracted. This may not be noticed in the exhibition of faulty oc- clusion or irregularities but a careful study of the features will show lack of artistic contour. Let us here consider the order in which the temporary teeth are replaced by the permanent set. By reference to Fig. 142, you will see that the order differs somewhat. EXTRACTION OF TEMPORARY TEETH 271 The lower figures represent the order of eruption of the temporary set. The upper figures represent the order of the replacement by the permanent set including this first permanent molar. Nature has wise reasons for this change in the order. The Inferior Teeth Generally Precede the Superior in the an- terior part of the mouth by a few w^eeks and in the posterior part by a few months with the exception of the third molars. The inferior third molars sometimes precede the superiors by years. It must also be borne in mind that the variance in length of time and age of erup- tion is shorter in the case of females than of males. Difference in Time as to Sex. Some females erupt their third molars as young as the sixteenth year, some males do not erupt them as late as the twenty-seventh year. They may be in part or entirely wanting in either male or female during life. Thev are sometimes Fig. 143. — Irregularity resulting from premature extraction of the first deciduous molar. so far retarded that they do not erupt until after the extraction of the first and second molars late in life. This sometimes gives rise to an idea in the patient's mind that he has at least part of a third set of teeth. Compare Orders of Eruption. A careful consideration of the two tables will show that in the temporary set the cuspid teeth erupt before the temporary molars, while these are replaced by the per- manent teeth in a different order. The first temporary molar is re- placed by the fii-st Incuspid. Then the second temporary molar is replaced by the second bicuspid and next we have the cuspid tooth comirii^ into ])]nco, forming Ibe keystone of the arch. The Reason for Nature's Change of This Order. At five years we find the full (•onii)l(;nient of teinpoi-aiy teeth in i)lace, only twenty in number. Then nature j)Uts in this dividing line by putting into place one ])f'rnianent tooth, tho first permanent molar, before she 272 . OPERATIVE DENTISTRY makes any attempt at interfering with the temporary arch already established. AVhen this tooth is fully in place nature begins her work of re- placement. First come the centrals, then the laterals, and if Ave were to follow the order in which these same temporary teeth were erupted we would next have the cuspid, but not so, we have the first temporary molar lost and replaced by the first bicuspid, and as this temporary molar is lost, the first bicuspid has a space to occupy between two teeth, which should be in position to guide and assist it to proper place, leaving the second temporary molar in position to hold the first permanent molar in its correct posi- tion. Then nature replaces the second temporary molar with the second bicuspid. Note that these two temporary molars are wider than the permanent bicuspids taking their place, but the cuspid of the permanent set is Avider than the temporary cuspid. Loss of Temporary Cuspid. As soon as the temporary molars have been replaced by the bicuspids, the temporary cuspids should be lost and replaced by the permanent cuspids, which as stated before, forms the keystone of the arch, and being a little wider wedges the two bicuspids quickly back into position against the first permanent molar. Coming into position just in this order and at this time it is easily seen how the first permanent molar is kept in its proper place. At this time the question may arise as to how the permanent centrals and laterals find sufficient room, be- ing so much larger than their predecessors. This is compensated for by the development of the maxillte at this age. Some authors advance the idea that the difference in the space occupied by these four teeth was compensated for by the permanent bicuspids being smaller than the temporary molars. We cannot agree with this. For when the four incisor teeth are erupted in position in almost every instance the temporary cuspid retains its former and original place. Having completed the changing of the temporary teeth nature will add teeth to the posterior part of the jaw without any danger of subsequent irregularities. Evils Resulting From Disregarding the Order in Which the Temporary Teeth Are Replaced by the Permanent in Their Extrac- tion. For instance, if, as we are frequently requested by our patrons, we extract lateral incisors before the central incisors have attained nearly their proper height in the process of eruption, either one of the two evils may result. EXTRACTION OF TEMPORARY TEETH 273 The central incisors in the inferior maxilla stand on either side of the symphysis, or where the two segments of the jawbone unite. In the superior maxilla the central incisors stand on either side of the median line in the intermaxillary bones. If the temporary laterals are extracted before the centrals are fully erupted, should the jaw continue proper development, the central incisors will stand apart as they do not have the lateral incisors to hold them toward the median line. Thus when the laterals attempt to come into place, their space has been encroached upon and they may fail to crowd the centrals over to place. HoAvever in most cases the bones do not continue proper develop- ment and the space between the two temporary cuspids occupied by the four temporary incisors, is not sufficiently increased to ac- commodate the permanent incisors; hence the crowded condition frequently met with. Therefore no lateral incisors should be extracted until the cen- tral incisors are quite in position. If the central incisors do not seem to have sufficient room, instruct the patient to put pressure with the tongue or fingers in the labial direction which will put them into proper position; but for no reason whatever should the laterals be extracted before the centrals have attained their proper height in the line of occlusion. Next we lose the lateral incisors. As this tooth erupts after the temporary lateral has been extracted, it very frequently loosens the temporary cuspid, which by this time has had its root quite freely resorbed. Patients then request that the cuspid be extracted as the lateral has not sufficient room. Very frequently it will look as though this was necessary. However if we extract the cuspid at this point rest assured that there will not be room enough for the permanent cuspid, Avhen it wishes admittance to the arch. We should insist upon the retention of the cuspids and as the lateral crowds for room, development all through the jaw and especially at the median line will take place. In the superior jaw the intermaxillary bones materially develop at this age, and as the temporary cuspid is not lost until between the eleventh and thirteenth year the development is ample. So the incisor teeth (the two centrals and two laterals), have allotted to them the space between the temporary cuspids, as well as that which is made by the growth of the jaw between the time of their eruption and the loss of the cuspid teeth. Therefore the lateral, which did not seem to have space enough when it erupted will have ample space in five years as it is that 274 OPERATIVE DENTISTRY long before any teeth in its immediate vicinity are disturbed. Na- ture then skips this cuspid tooth which is to hold the incisors in place, and the first temporary molar is replaced by the bicuspid which has ample room and needs little attention beyond the re- moval of its predecessor at the proper time. Just at this point the second temporary molar may become decayed or lost and patients will insist upon its extraction ; but if by any means the patient can be made comparatively comfortable it should not be extracted as its removal allows the first permanent molar to move forward caused by the growing and developing second permanent molar at this age. When the first bicuspid is fully erupted to the line of mastication, we are justified in removing the second temporary molar to give place to its successor. During the eruption of the first bicuspid, the cuspid will very frequently become loose and pos- sibly hard to retain, and the patient will again insist upon its re- moval; but it should not be extracted at this time. Leave the temporary cuspid in position until all of the other teeth have been replaced. If the order which nature has mapped out has been preserved, an even set of teeth will result in almost every instance. If the order has been interfered with in the least, the patient's mouth is placed in a condition where gross irregu- larities, faulty occlusion, and great disfigurement is almost sure to result. Therefore the great necessity for the preserA^ation of na- ture's order in the extraction of the temporary teeth. It is the one thing to be looked after and adhered to and should be disregarded only in extreme cases, which does not mean merely the satisfaction of the ideas of parents. The operation of extracting temporary teeth is simple. If we have carefully looked the mouth over and decided that it is necessary to extract any tooth, it can be accom- plished with almost any pair of forceps. Great care should be taken not to take too deep a grasp upon the tooth, that the develop- ing permanent tooth, which is supposed to be close to its tem- porary predecessor, may not be injured in the removal of the tem- porary tooth. It is also advantageous to use a lance separating the gum from the tooth as the gum at or near the neck of the tooth frequently adheres quite strongly to the cementum. By using the lance, laceration of the parts is avoided. When there is nothing left but the separated or decayed points or unabsorbed portions of roots, it is best to remove them with a root elevator or chisel. CHAPTER XLI. LOCAL AND REGIONAL ANESTHESLi Definition. Local anesthesia is that term applied to the results obtained when only a {-ireumscribed part of the body is rendered without sensation. FiK- 144. — Horizontal injection, a represents place of puncturing tlie soft tissues. Divisions of Local Anesthesia ai-e s>irface aiicstliesia, iiiMlti-alion aii<-.sllicsi;i. iiil r;i-al vcolar ;iiicst licsia, and regional anesthesia (fre- quently called foiidiictive), 275 276 OPERATIVE DENTISTRY Fig. 145.— Perpendicular injection, a represents place of puncturing the soft tissues. Uses in Dentistry. Local anesthesia when rightly practiced and successfully used is the most practical anesthesia for exodontia minor surgical operations about the mouth, as well as most of the' delicate dental operations connected with pulps of teeth. The sue- LOCAL AND REGIONAL ANESTHESIA 277 cess of local anesthesia is based on a working knowledge of the oral anatomy, sernpulons asepsis, fresh drugs and a correct technic in their use. Anatomy. The knowledge of anatomy should embrace a clear understanding of the muscular attachments, the position of the foramen and a knowledge of the position of the trigeminal nerve with its complete ramifications. Cocaine. For many years cocaine has been almost universally used by the dental profession as the principal local anesthetic. Its Fig. 146.— Drawing representing the positions of needles in local anesthesia, j^, position for subperiosteal injection for surgical anesthesia; B, intra-alveolus injection. This will re- sult in surgical and sometimes dental anesthesia. This injection is subject to very severe criticism due to the liability of the introduction of infection. C, intra-alyeolar injection. Ihis will result in dental anesthesia and quite frequently surgical anesthesia on the side towara which the injection is made. toxicity was not clearly understood at the beginning and thus oc- curred overdosing particularly with stale solutions. It has been fully demonstrated that some individuals could stand heavy doses without showing systemic ill effects, while death would result in other ca.ses where only a small dose had been u.sod. For these rea- sons the profession has been hiuiling a substitute. That substitute seems to have been found in novocain. Novocain is ('(iiial to cocaine in anesthesia ])rodu(*ing power. It 278 OPERATIVE DENTISTRY is relatively non-toxic. It is particularly non-irritating even on the most delicate tissues. It is easily combined with suprarenin, and, so combined, does not loose its anesthesia producing power. Neither does it affect the action of the suprarenin. It can be Fig. 147. — First ijosition in the mandibular injection. boiled for the purpose of completing sterilization. Novocain is a non-habit producing drug, and, as claimed by the manufacturers, is derived from an entirely different source than cocaine, to which it is in no way related. The general effects upon the system af- ter it has been absorbed are scarcely perceptible. Neither the cir- culation nor the respiration suffers and the blood pressure is not LOCAL AND REGIONAL ANESTHESIA 279 iiici-eased. From experiiueiits it has been found to be only one- seventh as toxic as cocaine. Doses. The best solution for dental uses is probably the two Pig 148— Second position in the mandibular injection. This position is taken for the deposit of the anesthesia for the lingual nerve. per cent solution for both the inliltration and the regional nietbods. The iiiaximurii dose of a two per cent solution is twenty-four cubic ceiitiiiioters. Such a quantity would never be called for in any dental operation. 280 OPERATIVE DENTISTRY Suprarenin is added to contract the capillaries and prevent ab- sorption and infiltration into the tissues beyond the field of opera- tion, thereby increasing the duration and strength of the anesthesia. It is also added in certain cases to decrease the flow of blood. Fig. 149. — Third position for the mandibular injection. Dosage of Suprarenin. Difeering from the amount of novocain used the suprarenin should be varied for individual cases. In fact it has probably been the practice of surgeons to use too strong a solution of suprarenin in their local injections. Preparing the Solution. In a dissolving cup, place a tablet of LOCAL AND REGIONAL ANESTHESIA 281 novocain and siiprarenin to which add Ringer's solution Q. S. to make a two per cent solution of the novocain. Boil over the open flame for one-half minute to sterilize. Fig. 150. — Fourth and last position for the mandibular injection. Ringer's Solution is made as f()]h)ws: Ringer's ta])lots; sodium chloride, 0.050 gt;itii; calcium chloi-ide, 0.004 gram; potassium chloride, 0.002 gram. Dissolve leii tablets in 100 cubic centimeters ^82 OPERATIVE DENTISTRY of aqua dest. Sterilize by boiling and put in bottle double corked to be ready for use when needed. Stale solutions of novocain and suprarenin should not be used. It should be mixed fresh for each operation. It should not come in contact with anything but the boiling cup and the syringe and should not be left longer than necessary in either of these. Care of Novocain Tablets. The tablets should not be touched with the hands and should be kept in a bottle, rubber-stoppered. The solution should be as clear as water and discarded as soon as it shows a light pink color. Fig. 151. — A very clear and easy case with the needle in the best position for the mandibular injection. Surface anesthesia is anesthesia produced by topical application. The method is of advantage upon mucous membranes, as they ab- sorb the solution rapidly. The effect is generall}^ not deep. How- ever, applied to the gum it is usually sufficient for fitting bands and crowns or the finishing of fillings at the gingival margin. A pellet of cotton saturated with a tAventy per cent solution of novo- cain and packed on the floor of the nasal cavity over the incisor teeth will many times anesthetize the incisors of the respective side LOCAL AND REGIONAL ANESTHESIA 283 sufficient for operations upon the dentine and even for pulp extir- pation. Infiltration Anesthesia is the method whereby anesthesia is pro- duced by injection of the tissues about the nerve endings. The suc- Fig. 152. — This represents a difficult case where the lingula is almost entirely wanting and the needle has entered the sulcus too low and may yet l)e engaged in the tissues of the external pterygoid muhcle which it must have penetrated to reach this positicHi. ce.ss of the methotl dcjx'iids upon' the tlvorouf^liness witli wliich the tissues to be operated upon are infiltrated. Tf any nerve endinjjs are missed only partial success is ohliiincd. T\iv infillr-ition 584 OPERATIVE DENTISTRY method is of advantage in the extraction of non-vital teeth, roots and parts of roots. It is the best method for the extraction of all deciduous teeth and roots. This method is used for any of the teeth in the maxilla, but the greatest success is with the single- Fig. 153. — The same mandible shown in Fig. 152 with the needle passed to position suiificiently high to be above the lingula represented by a. rooted teeth. With the mandible the infiltration method is of little service posterior to the cuspids when vital teeth are involved. There are but two injections to consider with the infiltration method in dental operations, namely, the horizontal and perpendicular. LOCAL AND REGIONAL ANESTHESLA. 285 The Horizontal Injection for the bicuspids and molars excepting the third molar. By this method several teeth may be injected with only the one puncture of the tissues, thereby materially less- ening the liability of infection. This injection is contraindicated in diseased tissue. The Perpendicular Injection is applicable for all single-rooted teeth. The needle should generally be inserted just below the gum margin and the point carried lingually or buccally of the apex of Fig. 154. — This is a mandible which belongs to a class on which it is very hard to give a mandibular injection. Note that the internal oblique line is continuous up to the sigmoid notch. The lingula (a) is one cm. higher than normal and is only about four mm. back of the internal oblir|uc line. Conditions like this possibly explain why even the most expert sometimes do not get results upon first attempt. the tooth the anesthesia of which is desired. The solution is in- jected without pressure and the needle does not go sub-periosteal as in distinction from the intra-alveolar. The quantity of solu- tion to inject is about one and a half cubic centimeters for the horizontal injection and about one cubic centimeter for the per- pendicular. A one-inch needle of small size is best suited for all infiltration work. Intra-alveolar Anesthesia has for its object the blocking of the 286 OPERATIVE DENTISTRY nerve before it enters the pulp of an individual tooth by injecting deeply into the alveolus. There are two injections in this method. They are the pericemental and the subperiosteal, or intraosseous. Tlie Pericemental Injection has been the most widely used of all the methods of local anesthesia up to this time, for the reason that it requires the minimum amount of the drugs used. This is a point Fig. 155.- — First and ideal position for giving the mental injection, a represents the posi- tion of puncturing the soft tissues. With fleshy patients the syringe barrel will of necessity have to be more anterior. of great importance in the use of cocaine. However, with the ad- vent of novocain the method will be used less frequently, owing to the liability of infection. The method has been useful in sur- gery, in extracting teeth, due to the accompanying infiltration of surrounding tissues. The needle should be short, say one-fourth of an inch, and of twenty-eight or twenty-nine gauge. LOCAL AND REGIONAL ANESTHESIA 287 Tlie Suh-periosteal Injection in intra-alveolar anesthesia is of the greatest use in operating upon vital dentine and pulp extirpation. The needle should be short and stocky, twenty or twenty-two gauge. It is inserted beneath the periosteum and even into the alveolar process itself, as near as possible to the apical foramen of the tooth to be operated upon. Considerable force is used in both of Fig. 156. — Second position for giving the mental injection, showing the linger compressing the tissues over the needle inside of the mouth to facilitate injecting tl>e canal. the intra-alveolar injections in coiinlcr distindion of all of the other methods of locjil anesthesia. Regional Anesthesia Conductive Anesthesia is sliietly a neive blocking process whereby a region of llie desired e.xlent is anes- thetized. The method is not new^, having been ])rac1iced more or less since the latter eighties, but has received a great impetus, due 288 OPERATIVE DENTISTRY lo the production of an agent like novocain which is comparatively safe for general practice. Regional anesthesia is by no means limited to the field of dentistry, but its use is as broad as the field of surgery on mankind, as well as that on the lower animals. The surgeon has but to know his anatomy to be able to render a region as void of sensation as though the part had been amputated from the body. For instance, the arm is now operated on without pain, even to amputation, by surrounding the axillary nerve with a puddle of a two per cent solution of novocain with suprarenin, reached with a needle in the top of the shoulder posterior to the clavical and internal and anterior to the scapula. Aside from the completeness of the anesthesia obtained, regional anesthesia has to recommend it the fact that the injection is made far from the field of operation, which is many times undergoing pathological changes often due to bacterial invasion. About the face, we have seven separate and distinct nerve blocking operations for regional anesthesia. The injections are; Gasserian ganglion, Spheno-maxil- lary, Pterygo-mandibular, Mental, Infra-orbital, Zygomatic, and Posterior and Anterior palatine. The Gasserian and Spheno-maxillary Injections are employed for major surgical operations about the face and will be passed over by simply mentioning them, as the strictly operative dentist will have no need to employ them. However, the remaining five injec- tions are of vital interest to the general practitioner of dentistry and will be taken up in the order given. Pterygo-Mandibular Injection has for its object the blocking of the nerve supply to the lateral half of the mandible and the im- mediate overlying tissues. Technic of Injection. Palpate the posterior molar triangle hav- ing first sterilized the immediate field of puncture with campho- phenique. Then find the internal oblique line. Puncture the tis- sues over its inner edge, using a forty-five millimeter iridio-platinum needle, one centimeter above the plane of the inferior teeth with the barrel of the syringe resting on the occlusal surfaces of the bicuspids of the opposite side, as shown in Fig. 147. Push the needle point four or five millimeters into the tissues. Now swing the syringe to the position shown in Fig. 148 for the lingual nerve. Again swing the syringe into the position shown in Fig. 149. Push the needle into the tissues, closely following the inner surface of ramus for a distance of about two centimeters in all (see Fig. 150), varying with the size and age of the patient. To follow the inner LOCAL AND REGIONAL ANESTHESIA 289 Fig. I37. — Position of needle in giving the infra-orbital injection, o represents the place of puncturing the soft tissues. If it is desired to accompany this injection with the perpen- dicular infiltration injection, the soft tissues should be punctured midway between the point marked a and the gingival margin of the gum. surface of the ramus will necessitate the swingin<>: of the syringe to the median line as the needle proj^resses. It is very essential that the needle passes into the sulfus iiiandihularis, above the lingual, or el.se it will pa.ss over this int.i llic pici-ygoid muscle, of- 290 OPERATIVE DENTISTRY ten resulting in false unilateral ankylosis, generally temporary, but sometimes more or less permanent and always to be avoided. If anesthesia of only the pulps of the teeth is desired, the special part of the injection for the lingual nerve should be omitted, as there is less liability of injecting bundles of muscle fibers. In case injection is made for surgical purposes, as the extraction of the first molar and bicuspid, an infiltration injection had best be made buccal to the tooth or teeth to be extracted to include the descend- ing branch of the buccal branch of the third division of the fifth, which is given off just above the pterygoideus internus and ener- vates the soft tissues of the biscuspids and molars buccally. An- esthesia occurs in fifteen to twenty minutes and lasts about one hour, sometimes longer. If longer anesthesia is desired, the amount of the injection is to be increased up to four cubic centimeters. The first sign of anesthesia is the numbness of the side of the tongue if the injection for the lingual nerve has been included and of the lip above the mental foramen on that side. These are the signs of a successful injection and occur in a very short time, yet the deepest state of the anesthesia may not work back to the pos- terior molars for twenty to thirty minutes, as frequently happens with operations for the extraction of lower third molars. Mental Injection. The mental injection is made with a one or two centimeter needle passed as shown in Fig. 155. The operator should compress the mucous membrane and tissues over the foramen. When the needle is felt under the finger (see Fig. 156) one cubic centimeter should be injected while pressing which will direct the solution through the foramen into the mandibular canal, anesthetizing the first bicuspid, cuspid and incisors of the respec- tive side. Infra-Orbital Injection. This injection is made in the same way as that described for the mental foramen, using the same length of needle and one cubic centimeter of the solution. Dental and surgi- cal anesthesia is obtained in the bicuspids, cuspid and incisors of the respective side. Zygomatic Injection. The long needle is inserted over the roots of the second superior molar progressing upward, backward and inward, depositing some of the solution as the needle progresses, until the position of the needle is as shown in Fig. 158 where the last of the solution is deposited, in all two cubic centimeters. This injection will reach the posterior superior alveolar nerve and the middle superior alveolar in case it is given off before the maxillary LOCAL AND REGIONAL ANESTHESIA 291 Fig. 158.— I-inal position of the needle in giving the zygomatic injection, a represents the place of puncturing the soft tissues. nerve enters the iiifi-a-orl)it;il canal. It is many times advisable to add to this the horizontal infilti'ation injection as shown in Fig. 144 to reach the anterior superior alveolar, the branches of which anastojHose with the branches of the middle alveolar. This zvfroniatic injection especially when assisted by the horizontal in- 292 OPERATIVE DENTISTRY jection will give dental and surgical anesthesia of the biseuspids and molars of the respective side. Palatine Injections. The needle is inserted above the gingival margin of the mesial part of the third molar for the posterior palatine and passed upward and backward to the palatine process, injecting one-third of a cubic centimeter. For the anterior pala- tine the needle is inserted lingually and above the gingival margins of the superior central incisors and passed upward and backward to the anterior palatine canals, depositing one-third of a cubic centimeter. These injections will anesthetize the palatal part of the gums for surgical work, as extractions. In Conclusion. Always use the simplest method that will be successful. Do not inject pathological tissue. Avoid infection. Use only fresh solutions. Do not inject muscle tissue. Use a solu- tion that is isotonic. Attempt regional anesthesia only after care- ful study and preparation. CHAPTER XLII. THE USE OF FUSED PORCELAIN IN FILLING TEETH. Definition. A porcelain inlay is a filling made of dental porce- lain and retained in position by cement. A Dental Porcelain is a solidified mass of silicious substances suspended in a flux of fused silicate. Composition. Dental porcelain is composed: First, of the basal ingredients which are refractory, as silex, kaolin, and feldspar. Sec- ond, fluxes used to increase the fusibility. Those in common use are sodium borate, or borax, (NaoB^O-), sodium carbonate (NagCog), and potassium carbonate (K2CO3). Third, metals and oxides used as pigments. Silex (SiOo) is the oxide of silicon. It is an infusible substance, insoluble except in hydrofluoric acid and is used to give strength to the porcelain. It gives it more translucent appearance. Kaolin [Al^(SiOj3.4H20] is the silicate of aluminum. It is added to the porcelain to give stability, and permits unfused porcelain to be molded and carved in the shaping of the contour. Feldspar [KoOAlo03( 8100)6] is the double silicate of aluminum and potassium. It forms over eighty per cent of the basal mass of porcelain and adds translucenc3\ Pigments. The various shades and colors in porcelain are pro- duced by the addition of precipitated gold, platinum, purple of cassius, oxides of cobalt, titanium, iron, uranium and silver, pro- ducing the colors of red, yelloAV, blue, green, broAvn and gray. High-Fusing Porcelain. By high-fusing porcelain is meant a porcelain that requires five minutes or more to fuse at a tempera- ture exceeding the fusing point of pure gold. Low-Fusing Porcelain. This is a porcelain that requires less than five minutes to fuse at a temperature not exceeding the fusing point of pure gold. This division is one of creation by the manu- facturers and commonly accepted by the profession. However the distinction is only relative as porcelain has no definite fusing point, as any enamel ov tooth foundation body may be fused on a matrix fif purf yold ii' ciKjiiifl) time is yivoii to the fusing pi'ocess. Effects of Fusing at Lower Temperatures and a Longer Time. A more homogeneous mass is produced. A more characteristic color is maintained. A less friable filling is produced. 293 294 OPERATIVE DENTISTRY A High-Fusing Porcelain May Be Made Low-Fusing by repeated fusing and grinding. In Building a Filling by Layers the first layer should be fused to a state of high biscuit otherwise the process of fusing the sub- sequent layers will over-fuse the first. High Biscuit Fuse. Heating the porcelain sufficient to obtain shrinkage, but not enough to glaze. Fine Grinding. The more finely porcelain is ground the lower the fusing point from the same formula and the greater the shrink- age. Size of Mass. The larger the mass the greater the length of time required to fuse. Amount of Flux. The more flux a porcelain contains the great- er the liability to bubble, which liabilitj'' increases as the tempera- ture is raised. Shrinkage in Fusing. High fusing porcelains shrink from fif- teen to twenty-five per cent. Low fusing porcelain shrinks from twenty to thirty-five per cent. Spheroiding. All porcelains have a great tendency to spheroid when over-fused. A Basal Body is porcelain composed of basal ingredients and the pigments. A Foundation Body is one composed of basal ingredients to which has been added a flux to increase fusibility, and has been ground less fine than enamel body to raise fusing point and give stability as to form. An Enamel Body is a basal body which has been more finely ground and to which there has been added more flux to increase fusibility. The Advantages of the Porcelain Inlay. When skillfully made they more nearly harmonize with tooth structure in appearance. Thermal changes do not readily affect the pulp in vital cases as porcelain is not as good a conductor as metal. Margins of cavities well filled with porcelain are not readily at- tacked by caries, as cement dissolves out of the margin to a depth only equal to the breadth of the line exposed. Patients are relieved of sitting with the rubber dam in position for protracted periods. The Disadvantages of the Porcelain Inlay. The friability of porcelain restricts its use to locations removed from great stress. It is necessary to omit the marginal bevel in all cavities, as the USE OF FUSED PORCELAIN IN FILLING TEETH 295 edge strength of porcelain is no greater than full length enamel rods. The Cavo-surface Angle should be that which the cleavage of the enamel gives, or about a right angle. Its greatest disadvan- tage is the fact that the inlay must be set upon unclean walls as the whole process must be done under moist conditions; moisture being necessary to maintain the color of the teeth while trying to imitate their shade. This prevents the placing of the filling upon freshly cut surfaces M^hich have not been moistened, the greatest enemy to all inlay fillings. Another disadvantage is that the retention of the porcelain de- pends upon the integrity of the cement, which is not wholly pro- tected at the margins. While porcelain inlays fit the cavity from a practical standpoint, the fact exists that they never exactly fill the cavity, the cement taking up the space resulting from the mis- fit, and is exposed in proportion to the amount of existing space at the margins. Indication for Porcelain Filling'. Porcelain is indicated in the following : In cavities in the anterior location in the mouths of patients who have an appreciation for esthetic qualities of dental operations. In cavities of Class One Avhen they occur in defects on labial surfaces. In cavities of Class Three when much of the labial wall is gone and rather strong lingual wall remains. In cavities of Class Four, plan three, vital teeth with rather thick incisal edge, not subjected to great stress in articulation. In cavities of Class Four, plan one, when proximating tooth is not in position as when the missing tooth is worn upon a plate or is to be subsequently replaced with a crown or bridge. In cavities of Class Four, plan four, in upper teeth when the lingual surface does not articulate. In gingival third (Class Five) in anterior teeth exposed to view when patient smiles. In cavities of Class Six on the six anterior teeth, when the porce- lain is built to a thickness of at least two millimeters, and in pulp- less lower molars, restoring the entire occusal surface. Contraindications. Porcelain is not indicated in the cavities not i;bovc mentioned, and in all locations subject to great stress and where good access form is difficult to obtain. CHAPTER XLIII. PEEPARATION OF CAVITIES FOR PORCELAIN INLAYS The filling of teeth with porcelain demands some change in the usual and accepted form of cavity preparation for other materials. Access Form. Access form reaches its maximum in porcelain filling. Even greater access is required than for the gold inlay. Hence preliminary separation should be practiced with all proximal fillings, before forming the matrix, and generally mechanical separation is of advantage when setting the filling. Outline Form for Porcelain Inlays. Outlines must be extended to regions of sound enamel. The obtaining of full length enamel rods supported by sound dentine is imperative. Extending to self- cleansing margins is of additional advantage, yet not so impera- tive as with gold filling, as secondary decay is not as liable to take place about a porcelain filling. The outline should not follow a developmental groove nor cross a ridge at its extreme eminence. Sharp angles in outline should be avoided. Extension for prevention as applied to the embrasures is not as great as with metal fillings. Extension for Resistance to Stress at margins is more essential than with gold, due to the friability of porcelain margins. Resistance Form for Porcelain Inlays. The rules for flat seats for all fillings apply equally to porcelain fillings. The use of the step in Class Four is essential to give added resistance to the tip- ping strain. Margins should be extended to locations less fre- quented by the crushing strain. Retention Form for Porcelain Inlays. Maximum retention form is required in all directions except one, until the matrix has been formed and the filling made ready for setting, when retention should be added in the remaining direction. Acute line and point angles should be avoided; all angles being rounded angles until the matrix is formed. Convenience Form for Porcelain Inlays. The filling of teeth with porcelain requires more cutting for convenience form than for any other method. This fact makes such fillings contraindi- cated many times, due to the great loss of tooth substance neces- sary to properly form the matrix and introduce the filling. Pre- vious separation Avill overcome this cutting to a large extent with this as well as other fillings. 296 PREPARATION OF CAVITIES FOR PORCELAIN INLAYS 297 Finish of Enamel Walls. All finishing of enamel avails must be completed before forming the matrix. The cavo-surface angle should be a right angle as the strength of fused porcelain is about equal to supported enamel margins. If a bevel angle exists it should be deeply buried. Toilet of the Cavity. This is attended to the same as with other inlay fillings before forming the matrix. Another Cavity Toilet is necessary just before setting the in- lay. This consists in washing the cavity with chloroform to dis- solve any oily substances adhering to the cavity walls. This is Fig. 159. — Cavity preparation for a Class Two porcelain inlay, non-vital case with the porcelain occupying a portion of the pulp chamber. followed Avith absolute alcohol and moderately dried. Excessive desiccation is not required and in fact should not be practiced as the integrity of the cemental substance in the enamel is injured and liability to marginal checking increased. Preparation of Cavities of Class One. Defects in enamel. Porce- lain is indicated in cavities on tlie labial surfaces of the six an- terior, due to faulty enamel. These are shown as small orifices in the enamel surface, generally rounded in form, and is the result of imperfect development. The cavity should bo not loss than two millimeters in width at its narrowest point, as a smallor cavity than this hinders proper working. 298 OPERATIVE DENTISTRY Avoid the Exact Circle in outline, as this will bewilder the oper- ator as to the position when setting. In case the outline is so near a circle as to make position questionable, the axial wall should have a small rounded pit at one side to guide the operator in set- ting. The Axial Wall should, in large cavities, be the miniature of the tooth surface in which it occurs. The axial wall of small cavities should have a rounded groove cut around the entire circumference. The Surrounding' Walls should meet the axial at an obtuse angle to relieve any undercuts before the matrix is formed. When the Fig. 160. — A Class Three cavity labial approach for porcelain inlay. Fig. 161. — A Class Three cavity labial approach for porcelain inlay. inlay is ready to set give the cavity retentive form by making the base line angles acute. Cavities in Proximal of Bicuspids and Molars. Class Two. Ex- perience has taught us that porcelain is not indicated in this class of cavities. Their location subjects the filling to extreme crushing strain which porcelain will not stand. The occlusal surfaces are of an irregular shape and made up of a great variety of forms with surfaces in any number of planes. This makes the right angle cavo-surface angle demanded in porcelain filling improbable and results in exposing porcelain margins of an acute angle. (Fig. 159 may be used.) PREPARATIOX OF CAVITIES FOR PORCELAIN INLAYS 299 Cavities in Proximal of Incisors and Cuspids Not Involving- the Angle. Class Three. This class of cavity is ideal for porcelain in- lays and is by far the most sightly filling Avhen properly done. These Cavities Should be Divided Into Two Classes in accord- ance with the three different lines of approach. First division, labial approach; second division, lingual ap- proach. Fig. 162. — A Class Three cavity lingual approach for porcelain inlay. Labial Approach, This approach should be decided upon when any considerable amount of the labial enamel is to be replaced and a lingual wall is possible. (Figs. IGO and 161.) The Gingival Wall should be extended gingivally to include all affected enamel. It should be flat axio-proximally and meet the axial wall at an angle slightly acute. It should meet the lingual wall at an angle slightly obtuse. The Axial Wall should be flat ]al)io-]ingually and be continu- ous from the axio-liiigual line angle to the labial cavo-surface angle which results in the entire removal of the labial wall. This wall should meet the lingual and incisal walls at an acute angle. The incisal lingual line angle should bo slightly obtuse. This results 300 OPERATIVE DENTISTRY in a cavity retentive in all directions except to the labial which gives it "draw" in this direction. Lingnal Approach. The whole general plan is reversed result- ing in the retention of all or a good portion of the labial wall and an entire absence of the lingual wall resulting in the draw being to the lingual. To Resist the Tipping Strain the lingual step may be added. This is done by cutting away a sufficient amount of the lingual en- amel resulting in two axial walls. One will face the proximal and Fig. 163.- — A Class Four cavity incisal approach for porcelain inlay. Fig. 164. — A Class Four, plan one, inciso- proximal approach for porcelain inlay. the other the lingual. This creates a line angle where the two walls unite, the axio-axial line angle which should be a rounded angle. Just before setting the inlay the axial wall should be slight- ly grooved next to the surrounding walls, except in the region of the incisal point angle. Cavities in Proximal of Incisors and Cuspids Involving the Angle. Class Four, Plan One. This plan of angle restoration may be suc- cessfully accomplished with porcelain when the conditions of stress would permit of this plan being used with any other ma- PREPARATION OF CAVITIES FOR PORCELAIN INLAYS 301 terial. The cavity form is the same as that just described for a gold inlay. Proximal Approach May be Used in this instance under some conditions. The incisal approach may be used "when excess sepa- ration has been produced a little greater than the length of the in- cisal line angle, as "vvell as more than the thickness of the inlay measuring from contact point to the greatest depth of the axial wall, "which permits the filling entrance from the incisal. To Break the Cement Line on the Incisal Edge a rounded groove Fig. 165. — A Class Four, plan two, with double step for porcelain inlay. should l)e made fi'om the external end of the incisal line angle to the incisal cavo-surface angle. Plan Two, Class Four, is suitable for porcelain filling provided the material will stand the strain at union of step and cavity proper. The double step is advised. (Fig. 164.) Plan Three, Class Four. The addition of the lingual step makes many angle lestoiations with porcelain practical, as the tipping strain can be well provided for by grooving in the lingual axial wall next to the distal or mesial wall according to whether the cavity is distal or mesial. The cavity should be so shaped that the draw is directly to the incisal. The gingival wall should be 302 OPERATIVE DENTISTRY flat and meet both axial walls at an acute angle. The axio-labial line angle should be acute. The lingual axial wall should be con- cave. The axio-axial line angle should be a rounded angle and continue out to the incisal cavo-surface angle. Plan Four, Class Four. In angle restoration the creation of both incisal and lingual steps is most popular. The incisal step is formed in much the same way as when gold is to be used. However the pulpal wall should be placed farther from the incisal edge and be laid in a plan less acute to the axial wall than for gold. The angle formed by the junction of these walls, the axio-pulpal angle, should be rounded. In forming the lingual step the enamel may be removed entirely to a level of the gingival wall, or it may be only as much of the incisal portion as may seem necessary to strengthen the body of porcelain in the incisal region and resist the tipping strain. Fig. 166. — A Class Four, plan three, for porcelain inlay. The Double Step is of service in cases where there has been ex- tensive loss of tooth structure, particularly in non-vital cases. This plan results in a gingival wall and two pulpal walls ; also in two short axial walls placed on an equal number of levels. The gingival and pulpal walls should be made to meet the axial walls at acute angles. Each of the two pulpal walls should be grooved from the connecting axial walls, and each axial wall in the central portion resulting in a continuous groove from the gingivo-axial line angle to the incisal edge. This cavity has draw directly to the incisal. Cavities Occurring- in the Gingival Third of Class Five. Labial cavities in the gingival third are favorite places for porcelain and should to a large measure displace gold. If the cavity extends be- neath the gum line, the gum should be forced from position by PREPARATION OF CAVITIES FOR PORCELAIN INLAYS 303 previous packing of gutta-percha or cotton saturated with chlora- percha. Outline Form should be the same as for other filling. The axial vail should be the miniature of the tooth surface wherein the cavity occurs. The gingival Avail should be flat and meet the axial at an acute angle. All other surrounding walls should meet the axial at slightlj' obtuse angles. This gives a cavity with draAV to the labial alloAving the incisal portion to saving out in advance, the inlay going to place gingival first. This hinge movement is slight but constitutes a valuable point ^^^^L^ ^ Fig. 167. — Class Five cavities for porcelain inlay. in subsequent retention. Just before setting the inlay the axio- incisal line angle should be sharpened to add retention foi-m. In cases where the decay resulting in a cavity is materially TiorsesJioe in form the cavity may be filled by two distinct o])oiati()iis. This is accomplished by filling the cavity with cement and cut- ting out one-half and filling with porcelain. This completed, the other half is cut out and the operator then proceeds to fill that por- tion. This rcsulls ill two poi'fclain fillings with cement between. One Point Must Be Observed. Tlie fii-st portion of porcelain will necessarily slightly overlap a cement Avail. Before setting, this portion of the inlay mu.st be ground at the expense of the ex- ternal surface of the filling to reverse the di-aw, oi* this poi-tion of 304 OPERATIVE DENTISTRY the remaining cavity will be found with an objectionable under- cut hard to manage. Restoration of a Portion of the Incisal Edge. The general out- line in this class of cavities when they are simply a notch in the body of the tooth, is that of the half moon when viewed either from the labial or the lingual. HoAvever the lingual enamel should be removed for a greater distance root-wise resulting in a lingual step to provide against the tipping strain. The pulpal wall should have a groove mesio-distally in its central portion and extend well Fig. 168. — Incisal cavity for porcelain inlay. up along both mesial and distal walls, and with the larger cavities coming out to the cavo-surface angle. Restoration of the Entire Incisal Edge — Outline Form. The en- amel is chiseled root- wise till it is firm and will result in a thick- ness of porcelain at all points equal to at least two millimeters. Retention is accomplished by the addition of pins, or a generous lingual step, or both. In vital cases where pin retention is to be used there should be cut a V-shaped groove mesio-distally, the spreading angles of PREPARATION OF CA^^TIES FOR PORCELAIN IXLAYS 305 which should come just short of the dento-enamel junction labially and lingually, Mesially and distally it should continue to the cavo-surface angle. A pin hole should then be bored in the ex- treme ends of this groove not a great distance from the dento-en- amel junction in the dentine to receive the pins. AVhen the lingual step is to be added the enamel on the lingual is removed additional- ly to a distance root-wise at least equal to the labial exposure ; also an amount of dentine sufficient to make the newly created axial wall meet the two pulpal walls at right angles. If pins are to be added the holes should be bored in the floor of the pulpal wall nearer the labial surface. In Pulpless Six Anterior Teeth the pulp chamber may be rounded out and porcelain so baked as to form a post of porcelain for re- tention. Fig. 169. — A Class Six cavity using pin anchorage for porcelain inlay. This plan is also used with the gold inlay. Pulpless Molars are ti-eated in the same way. Treatment of Teeth With Malformed Enamel. The major por- tion or all of the enamel can he successfully replaced with porce- lain. The enamel is removed to the desired point resulting in a gingival wall entirely encircling the tooth. Sufficient dentine is removed in the incisal region to render the largest girth at the gingivo-axial line angle which is continuous around the tooth. This leaves a peg-.shaped bod}' of dentine over which the porcelain is telescoped. The method is termed the jacket crown and the method of construction and setting is fully described in the Avritings of others (*n r-rown work. CHAPTEE XLIV. THE CONSTRUCTION AND PLACING OF A PORCELAIN INLAY Following tlie completion of cavity preparation the next step in porcelain inlay filling is the formation of a matrix. A Matrix is a thin piece of metal shaped to the cavity form in which the porcelain is fused. Matrix Material. The matrix materials in common use are pure gold, pure platinum and platinized gold. Pure gold and platinized gold can be used only with Avhat is termed low fusing bodies, while pure platinum can be used with either high or low fusing bodies. Gold is more easily shaped to cavity form, but tears more easily and does not hold its shape as well after burnishing. Thickness of Foil. The most popular thickness of platinum foil to be used in the construction of a matrix is 1-1,000 of an inch. Thicker than this is difficult to manipulate, while the thinner foils tear too easily, and are more liable to distortion during the processes of building and fusing. Annealing of Matrix Material. This is best accomplished by placing the entire sheet of material as it comes from the supply house in the electric oven and bringing it to the desired tempera- ture before cutting off the piece desired for the case in hand. Pure gold and platinized gold should be brought to the full red heat or about 1,200° or 1,300° F. Platinum should be carried up as high as it is expected to carry the temperature during the process of fusing and held there for two or three minutes. It is not necessary to an- neal several times during the process of shaping the matrix. Methods of Forming the Matrix. There are three general methods in use for the construction of a matrix. First, burnishing directly into the cavity. Second, swaging over an impression of the cavity. Third, swaging into a model of the cavity. Each has its advantage in different cases and are recommended by all porcelain workers. However, the combination of the first and second methods will bring good results and is the method re- quiring the least time. Technic of the Combination Method. First take an impression of the cavity. If the cavity is large it is best to use modeling com- pound, trimming off that part which flares out over the external 306 CONSTRUCTION AND PLACING OF PORCELAIN INLAY 307 surface of the tooth. The matrix is then shaped over this iinpres- sion with the fingers, using the soft part of the ball of the thumb as a counter die. The most prominent parts of the impression will represent the deepest portion of the cavity and A\'ill assist in causing the matrix to reach this Avithout tearing which is accomplished by using the impression to crowd the matrix to position. The impression should be removed leaving the matrix, Avhich has been by this means partially swaged, in the cavity. The Removal of the Impression Without Carrying' Away the Matrix is accomplished by bending the portions of matrix exposed above the cavo-surface angle aAvay from the impression. The matrix should not be burnished down onto the external surface of the tooth until the other portion has been made to thoroughly con- form to the cavity walls. "When the impression has been removed the matrix should be thoroughly burnished to all cavity walls beginning at the seat of the cavity first. This burnishing is done with suitable smooth- faced instruments, keeping moistened chamois skin discs between the instrument and the matrix. The cavity should now be packed with damp cotton halls crowd- ing the matrix ahead of them to every part of the cavity. While this cotton is in position, the matrix should receive thorough burn- ishing at the cavity margins and finally be turned out on to the ex- ternal surface of the tooth a distance of one-fourth of a millimeter to one full millimeter in all locations except one, Avhieli may l)e tAvo or three millimeters. This one place will facilitate liandling during the process of fill- ing in the porcelain. The cotton may now l)e removed and gum camphf)!- ()]" gold inlay casting wax ci'ov\ded into the cavity over the matrix, filling the cavity nearly full with one piece of nmterial packed to place with a flat-faced amalgam burnisher as large as the cavity Avill admit. Removal of Matrix. The matT-ix is then removed from the cav- ity by sticking the tine of an cx])loi(r into the body of the cam- plior or wax near its central poiiioii. The matrix and wax or camphor still on the tine of the explorer should be immersed in alcohol if camphor has been used or chloroform if Avax has been used, which will immediately loosen the tine and dissolve the ma- terial from the matrix, aftei* which the nialrix shonld be picked np 308 OPERATIVE DENTISTRY in the lock tweezers at that portion where the metal has been left to extend the farthest from the cavo-surface angle. The matrix should now be passed through the alcohol flame when the camphor or Avax remaining will be burned off leaving no ash. Wood as an Impression. In simple small cavities it is well to shape a piece of soft pine (as cork pine) to proximately fit the cav- ity. This should be then introduced against the deepest portion of the cavity and given a few blows from the mallet which will cause the wood to conform to the floor of the cavity. This should then be used as an impression and the matrix forming proceeded with, as described when modeling compound has been used. The use of the stick with modeling compound on the end is of advan- tage in large deep cavities where the pulp chamber is to be filled with porcelain in place of metal pin. By this means it is possible to place a matrix well to the bottom of any cavity without tearing, provided the walls are regular and have the proper draw devoid of under cuts. Taking the Spring- Out of a Matrix. If a matrix seems to retain "spring" and does not seem to lay well on all surfaces, as fre- quently met with in complex cavity outlines, this may be removed by the following method : When cavity is thoroughly packed with wet cotton, stretch a piece of rubber dam over the matrix, cotton and all, and thoroughly burnish the entire outline. If ''spring" still persists, remove the matrix and anneal, and then repeat the method when it will be found that the fault has been removed. Selection of Porcelain. The selection of that portion of the in- lay which replaces dentine and that which replaces enamel should be attended to before the process of building begins. The part replacing dentine should be of foundation body coarsely ground and of a yellow color in all vital cases. In devital cases this shade may be darkened by the addition of the brown shade, and in. vital teeth for young patients, particularly if the cavity is shallow, or on a distal surface, the addition of white powder is of advantage to lighten the shade of yellow. The enamel shades may be decided upon after a careful study of the shades and hues found in each case. Delicate shading is se- cured by building one layer upon another, thus getting the benefits of reflected light. The deep and pronounced shades and colors are best obtained by building in sections. Teeth that are much of one color and not pronounced in lines of shades will be best represented by the layer method, while teeth that are decidedly yellow at the CONSTRUCTION AND PLACING OF PORCELAIN INLAY 309 cervix and pronouncedly blue at the ineisal edge are best repre- sented by building in sections provided ; the cavity involves both regions spoken of as in Class Four (proximo-incisal). After the different sections have been applied and brought to a hard biscuit fuse, a uniform layer of neutral color is applied over the whole and all fully fused. Applying- the Porcelain to the Matrix. The foundation body is put upon the porcelain or glass slab and sufficient distilled water, or alcohol or a mixture of both, added to make a stiff paste, stiff enough to retain its shape when taken up on the point of a spatula. A small quantity of this is laid in the bottom of the matrix and by a little jolting made to flow over the surface. This jolting is best produced by drawing the edge of a fine gold file over the tweezers holding the matrix. The additions should be continued until sufficient body has been added. Excess moisture is removed by repeated jolting and absorbing with blotting paper. Dark col- ored blotting paper is used so as to detect any paper fibers Avhich by accident adhere, which should be removed. The addition of dry porcelain of the same color will take up the excess moisture, the surplus adhering powder being brushed off with a small brush. In Case the Matrix is Torn, the opening has to be comparatively large to cause the porcelain to run through, unless the matrix is damp on the cavity side or too moist a mix is being applied. Should any of the porcelain flow through, it can be removed with a dry brush provided the porcelain has been rendered quite dry. Do not apply a wet brush to the cavity side of the matrix. The inlay should now be placed in the oven and fused sufficiently to produce the greater part of the shrinkage, but not to a full gloss. When removed from the oven if more foundation is needed it should bo added and fired to a high biscuit. The Enamel in Proper Shades is now added, either in layers or sections, and again fired to a high biscuit. The inlay should then be tried into the cavity for bulk and contour. If not correct more enamel is added. When the contour suits, the inlay is replaced in the oven and fired to a full glaze. The skill necessary to reproduce the colors of the teeth comes with practice and the longer one en- gages in this work the more often Avill the results please the oper- ator, Technic of Fusing- Porcelain. The furnace should be first heated up to a Ijriglit ]■(',(] and licl'l lliere for n minute or Uvo, to thor- 310 OPERATIVE DENTISTRY oughly warm the fire clay entirely through, and then the lever re- turned to the first button to maintain a v-'arm oven. When ready to fuse, the furnace is completely shut off provided the oven shows any redness. Never put an inlay mix into a hot oven, as it causes too rapid evaporation of the moisture, producing checks and an extremely friable porcelain. When the inlay is in position in the oven the lever is put on the second or third button and advanced only when the needle of the milliamperemeter ceases to advance. The heat should be increased gradually and when it has reached the desired degree immediately shut off. Each furnace has a way peculiar to itself and each oper- ator should learn the time for perfect results. Grinding- to Contour. After the final fusing the inlay should be tried in and ground to contour and articulation on the incisal or occlusal surface before removing the matrix. To Remove the Matrix. Drop the inlay and the matrix in alco- hol or water, then remove and peel the matrix from the inlay, draw- ing from the margins all around first, then from the body of the filling. This procedure prevents chipping at the margins. Etching- the Cavity Side of Inlay. When the matrix has been removed the inlay shoiQd be embedded, contour surface down, into a sheet of pink base plate wax. With a warm spatula it is sealed entirely around, being sure to cover the edges of the inlay on the cavity side for a short distance, say one-half millimeter. This leaves the cavity side exposed, upon which is applied hydrofluoric acid. This is applied by dipping a stick in the wax bottle in which the acid is delivered, and painting the inlay with a small quantity of the acid. Two minutes will generally be sufficient to thoroughly etch the surface. Toilet of Inlay. The inlay should be flooded with water, re- moved from the wax and placed in boiling water for a few minutes and then given a chloroform bath, and dried with warm air while laying on spunk or blotting paper, and should not be again con- tacted with the hands on the cavity side. Toilet of Cavity. The cavity should be rendered dry. All in- lays, and particularly the large ones, are best set with white ce- ment with the faintest tinge of cream. The attempt to match the color of tooth substance with the cement is an error as the pigment in the cement increases the shadow line which is objectionable. Use a white cement mixed to the consistency of greatest adhesive- ness yet thin enough to flow from between inlay and cavity walls CONSTRUCTIOX AND PLACING OF PORCELAIN INLAY 311 with light pressure. This will be about the consistency of thin cream. The cement should be thoroughly and rapidly spatulated and when the ''stick" is felt under the spatula it should be ap- plied to the cavity and the surface of the inlay which is immediate- ly placed. Use a non-corrosive spatula, preferably bone or agate. Apply to the cavity with a flattened orangewood stick. Press in- lay to position with a stick of orangewood using gentle pressure, gently tapping the end of stick with the knuckle of the forefinger, or blows of equally cushioned nature. In labial and buccal fillings (Class Five) the inlay should re- ceive gentle pressure for five or ten minutes. In proximal (Classes Three and Four) the filling should be gently wedged against the proximating tooth or tightly ligatured to position and so left for some hours. The Finishing- should be left till another sitting. If the building has been "svell done there will be little to do. All overhanging mar- gins should be dressed doAvn with fine stones and disks and the surface polished with small Arkansas stones, using a light hand and keeping the stones well watered. APPENDIX As a suggestion to those Avho use this book as a text in college teaching, the author submits the following courses based on the subject matter of the foregoing chapters and illustrations. Herein are also shoAvn the author's selection of instruments for doing the ■work and Dr. Rathbun's "dentech" to take the place of the pa- tients. While carrying out this course the freshman completes the first seventeen chapters. During the second year the student hurriedly reviews the first seventeen chapters and completes the remainder of the book. The courses in both the first and second years are quiz courses. The third year students review the book entirely w^ith the teacher giving lectures elaborating on each subject by adding personal ideas to give individuality to the course. The fourth year is devoted |o a study of the subject as presented by other writ- ers, each member of the class writing papers for the consideration of his fellow-classmen, who should be allowed to discuss the papers presented. Operative and Dental Anatomy Technic Courses FRESHMAN YEAR. First Semester. (1) Fourteen plaster tooth carvings, three times Black's measure- ments. Second Semester. (2) Fourteen bone tooth carvings, average measurements. (3) Six bone tooth carvings from models of extracted teeth. (4) Nine cavities as assigned in technic block, finished March 1st. (5) Twenty-four cavities as assigned in fourteen plaster teeth. finished May 1st. (See Figs. 13 and 14.) JUNIOR YEAR. First Semester. (6) Fill nine cavities in technic block. (7) Mount bone carvings and natural teeth on "dentcch." (See Fig. 177.) (8) Fill natural teeth as per following list. A. Second lower molar. Occlusal. Class One cavity. Expose 313 314 OPERATIVE DENTISTRY Fig. 170. — Excavators, group one. Chisels for securing outline form. APPENDIX 315 Fig. 171.— Kxcavators, group two. Si)Oons for removing softened dentine. 316 OPERATIVE DENTISTRY Fig. 172. — Excavators, group three. Enamel hatchets for completing outline form and ] flattening dentine walls. ■ APPENDIX 317 •"ig. 173. Kxcavators, group four. Instrumenls for cutting point angles and sharpening base line angles. 318 OPERATIVE DENTISTRY Fig. 174. — Excavators, group five. Hatchets and hoes for cutting ascending line angles and completing retention form. APPENDIX 319 Fig. 175.— Kxcavators, group six. Gingival marginal trimmers. InMrumcits for «:hnT)intr an.l finishing gingival walls. ' 320 OPERATIVE DENTISTRY I Fig. 176-B. Figs. 176, A and B. — Gold building pluggers.. Numbers one to seven inclusive are for building foil gold. These instruments have the same sized serrations and are made in conformity with the principles taught in Chapters XIX and XX. In- struments numbers eight to twelve inclusive are for building fiber gold. These five instruments have serrations specially adapted for use on this form of gold. In changing from foil builders to fiber gold builders or vice versa the surface of the gold should be gone entirely over, before add- ing the differently prepared gold, with the instru- ment with which the operator expects to condense the new gold. Fig. 176-^. APPENDIX 321 Fig. 177. — Dr. Rathhun's dc-ntech with teeth in position ready tor practice work. This appliance may be used either on the bencli or head rest of any operating chair. The author advises the advanced worlt with this on the dental chair to familiarize the student with positions. 322 OPERATIVE DENTISTRY pulp. Devitalize. Remove pulp. Fill pulp canals. Fill cavity vs/'ith silver cast inlay. B. Upper lateral. Lingual pit. Class One. Open and treat for putrescence. Fill pulp canal. Fill cavity with amalgam. C. Second lower bicuspid. Occlusal pit. Class One cavity. Open Fig. 178. — This shows a student who has kept his appointment with his patient, "Mr. Dentech." The student is required to keep an appointment book with this dummy patient the same as though the mouth to be worked on was animate. and treat for putrescence. Fill pulp canal. Fill cavity with tin. D. Upper central. Distal. Class Three cavity. Expose pulp. Devitalize. Fill pulp canal. Fill cavity with cement. E. First lower molar. Mesial. Class Two cavity. Devitalize. Remove pulp. Fill pulp canal. Fill cavity with tin, restoring con- tact. F. First superior molar. Mesial. Class Two cavity. Devitalize. Fill pulp canals. Fill with amalgam restoring the contour and con- tact. APPENDIX 323 G. Second superior molar. Class One cavity. Central pit rather large. Prepare so as not to injure the pulp in vital case. Fill with amalgam. H. First and second superior bicuspids. Mesial cavities. Class Fig. 179. — Forceps made after the patterns of the author. The middle and right hand pairs are spoon beak forceps, hollow ground and should be kept reasonably sharp by grinding. Two. Expo.se pulps. Use pressure anesthesia. Remove pulps. Fill pulp canals of both. Fill both cavities with tin. I. First inferior molar. T'lass Five. Prepare cavity and fill with amalgam without injury to the pulp. ./. Admitted to infirmary practice. 324 OPERATIVE DENTISTRY Second Semester. \ (9) Twenty-four cavities in carved bone teeth mounted on "den- i tech, ' ' duplicating those in plaster teeth of the freshman year. Cut ] and fill in the order listed, completing each filling before cutting the \ next cavity. \ Fig. 180. — Forceps made after the patterns of the author. The right hand pair is a combination of cow liorn and hawk bill beak. INDEX A Abrasion: causes not clear, 96 incisal, 97 mechanical, 195 Abscess: alveolar, acute, 179 alveolar, chronic, 224 Absorbents, 187, 194 Absorbent cotton, use of, 175 Access form, defined, 31 importance of, 31 surgical for, 31 Access form for: class two, first method, 58 second method, 59 third method, 59 class three, 72 inlays, 99 class two, 102 class three, 105 silicate, 150 Affected dentine, 29 Alloy, ageing of, 140 annealing of, 141 Alveolus, opening mouth of, 234 Amalgam: cavity preparation for, 141 contraction of, 140 cutting from the margins for, 144 defined, 139 edge strength of, 140 expansion of, 140 expressing mercury from, 143 flat seats for, 141 flow of, 140 history, 139 making the filling, 144 making the mix, 142 matrix, removal of, 114 matrix, use of, 141 maximum strength of, 140 Amalgam — Cont 'd objections to, 139 polishing of, 145 properties of, 139 proportion of alloy and mercury, 142 reception of, 129 trimming the filling of, 144 Anesthesia: conductive, 285 infiltration, 282 intra-alveolar, 201 local and regional, 275, 292 pressure, for pulp, 213, 214 pulp, 212 sensitive dentine, 202 sensitive dentine, general for, 202 surface, 282 Angles, avoided in outline, 34 avoided in outline, class two, 61 line, class two, 62 Angle restoration: conditions demanding, class four, 78 plans of, class four, 78 plan one, class four, 85 plan two, class four, 87 indications for, 88 plan three, class four, 89 indications for, 88 plan four, class four, 90 Appendix, 313, 324 Arsenic tri oxide: caution in use of, 217 combination, 215 poisoning from, 217 retainer, 216, 217, technic in, use of, 216 amalgam as a, 216 cement as a, 217 cotton as a, 217 stopping as a, 217 soreness from, 217 time of aiijtlication of, 217 325 326 INDEX Bevel angle, base of, 28 defined, 27 Broacli, cotton carrying, 226 Burnishing cohesive gold, 137 Calculus: salivary: composition of, 181 removal of, 183 serumal : appearance of, 183 deposited, 182 distinguished from, 184 removal of, 184 Canal point, size of, 227 Canal, filling, pulp: chlora-percha as, 227 general, 225-228 gutta-percha as, 227 immediate, 215, 218 material for, 225 most popular, 227 necessity of, 225 objective point in, 225 perfect, 225 ready for, 225 Caries: progressive stage of, 207 rapid, indications of, 167, 195 Carious dentine: in large decays, 44 in large proximal cavities, 44 predisposing causes, class one, 48 class two, 58 removal of remaining, defined, 44 Cavities: axial surface, 21 base of, 24 buccal and lingual surfaces, 55 cavo-surface angle, defined, 27 for fused porcelain, 295 class one, defined, 22 class two, defined, 22 early detection essential, 58 non-vital, 67 Cavities — Cont 'd class three, defined, 22 form of, 72 management of, 72 class four, 78-92 defined, 22 inlay, 63 class five, 93-95 defined, 22 prevention of, 93 tendency to spread, 93 class six, 96, 97 cause of, 96 defined, 96 early restoration in, 97 line angles in, 25 occlusal surfaces, 97 complex, 21 distal superior cuspids, 91 divisions as to manipulation, 22 groups of, 21 how named, 21 increased outline in, dangers of. - 37 laying of outline, 37 mesio-disto-occlusal, non-vital, 68 mesio-disto-occlusal, vital, 68 point angles in, 25 proximal, 21 simple, 21 stress from within, 38 toilet of, 45-47 Cavity nomenclature, 21-28 necessity of, 21 names, how derived, 21 Cavity preparation: completed, defined, 29 general consideration of, 30 gold inlay, 98-111 modification of form, 29 order of procedure in, 29 porcelain inlay, 296-305 Cements: amalgam, and, 170 cavity preparation for, 146 cement, int. v. defined, 148 cement, n. defined, 148 cement, t. v. defined, 148 INDEX 327 Cements — Cont 'd eementatiou, ii. do&ied, 148 gold, and, 1G9 porcelain, and, 171 retainer of arsenic, 217 varieties of, 146 Cementum, exposure of, 196 Children 's teeth, management of, 229-233 cavities, class one, in, 230 cavities, class two, in, 230 cavities, class three, in, 231 cavity preparation in, 230 early attention imperative, 229 exposed pulp, in, 231 extension for prevention in, 230 extension for resistance in, 230 filling materials in, 230 first difficulty in, 229 first visit of child, 229 inter-proximal grinding in, 231 root filling in, 232 Chip blower, use of, 176 Chloroform, 202 Clamp: cervical, use of, 194 methods of applying, 191, 194 Cocaine: for sensitive dentine, 277 local anesthesia, with, 277 Combination fillings, cement and amalgam, 170 cement and porcelain, 171 defined, 169 gold and cement, 170 gold, cohesive and non-cohesive 170 gold and platinum, 170 gold and tin, 169 object of, 169 silicate and amalgam, 172 silicate cement and fused por- celain, 171 silicate and gold, 171 Contact point, proper, 32 build of, amalgam, 144 class six, 97 condensing of, 132 position of, 132 Convenience form, 42-43 abuse of, 42 class one, 50 class two, 63, 60 class three, 77 defined, 42 distal superior cuspid, 92 inlays, 99 maximum required, 42 minimum required, 42 porcelain inlays, 296 previous separation lessening, 42 silicate, 154 sparingly used, 42 suitable instruments for, 42 D Dentech, 321 Deposits, 180 food as related to, 181 habits as to, 181 kinds, upon the teeth, 180 mouths most subject to, 181 salivary, prevention of, 182 time of, 181 Disinfection and pulp protection, 46 Disks and strips, are in use of, 46 Dryness, 187 importance of, 187 neglect of, 187 E Electric lamps, use of, 176 Enamel: defined, 97 edge, 97 malformed, 305 margin, 27 plane of, 45 Enamel walls, 45 axial, surface pit, 56 class one, 50 class two, 63, 67 class three, 77 inlay, class two, 104 inlay, class four, 109 328 INDEX Enamel walls — Cont'd inlay, porcelain, 297 silicate, 154 Examination of moutlis: care in, 175 instruments needed in, 175 light liand in, 174 when completed, 176 Exclusion of moisture, 186 as a time saver, 189 better view of the cavity, 188 decalcification detected, 189 for proper canal treatment, 188 for sterilization, 188 methods of, 186 pain decreased by, 189 Explorer, use of, 175 External enamel line, defined, 27 Extensions gingivally: buccal, class one, 56 buccal, class two, 60 Extension for prevention : approaching the gum, 56 buccal pits, 56 defined, 35 esthetic reasons, 74 Extraction of teeth, permanent, 233-268 care in, 263 forces used in, 234 general consideration of, 233 hemorrhage following, 267, 268 movements in, 234 positions in, 234 position of arms in, 240 position of hands in 240 position of operator for inferior, 238 position of operator for superior, 235 resistance of patient in, 243 rules for, inferior bicuspids, 253 superior bicuspids, 249 inferior cuspids, 249 superior cuspids, 245 inferior incisors, 245 superior incisors, 244 inferior molars, 259 superior molars, 256 Extraction of teeth: rules for — Cont'd. third, inferior molar, 262 third, superior molar, 262 temporary teeth, 269-274 early extraction, evil results of, 269 first molar, related to, 269 first molar, time of eruption, reasons for, 269 F Feldspar, formula of, 293 Finishing cohesive gold filling, 137 abrasives in, 138 burnishing in, 137 gingival excess in, 137 knife, in, 138 strips, in, 138 Floss silk, waxed, use of, 176, 186 G Gingival Angles, class four, 83 Gingival outline, class two, 61, 65 class three, 73 class five, 94 Gold: annealing of, 124 application of, 127 bridging of, 125 building of class five, 136 building of class six, 136 cement and, 169 cohesion of, 125 cohesive physical properties, 123 condensation, secondary, 137 condensing of, 127 covering of pulpal wall, with, 131 hand pressure in use of, 127 last portions of, class two, 133 layers of, 135 objectionable qualities, of, 123 order of stepping, 129 buccal cavities, 129 class two, 130 irregular outline, 129 occlusal cavities, 129 INDEX 329 Gold— Cont 'd platinum and, 170 preparation of, 126 specific gravity of, 125 starting a filling, class one, 129 class two, 129 class three, 133 class four, 135 tin and, 169 use of, in class five, 95 welding of, 123 Gum massage, 185 Gutta-percha, 16i base plate, 164 canal points of, 165 filling root canals with, 164 filling with, 164 preparation of filling, 164 separation with, 165 temporary stopping of, 165 H Hand pressure, cohesive gold, 12 S Health of patient, 207 Hydrogen dioxide, 185 Hj-peremia : active, 177, 206 passive, 178 stages of, 206 Hypersensitive dentine, defined, 195 caustic potassa in, 200 chloroform in, 202 cold air in, 199 dessication of, 198 destroying agents in, 199 electric current in, 199 formaldehyde in, 200 moisture, heat and cold in, 199 nitrous oxide in, 202 novocain, 201 oil of cloves in, 201 phenol in, 200 potassium bromide in, 202 rapid breathing in, 203 sharp instruments in, 203 silver nitrate in, 200 Bomnoforme in, 202 Hypersensitive dentine — Cont 'd treatment of, 195-203 zinc chloride in, 200 Incisal abrasion, class six, 97 Incisal angle: class three, filling of, 87 class four, 78 class four, direction of, 81 class four, to assist the, 86 Incisal edge, porcelain inlay, 304 Incisal line angle, class three, 75 Incisal outline: class three, 74 class four, plan one, 87 class five, 94 Infected dentine, 29 Inlays : beveling of cavo-surface angles, 100 carving the wax, 114 defined, 98 finishing the, 122 gold used, in, 121 heating the gold, for, 120 history of, 112 hole leading to model, 121 indications for, 98 investing, pattern of, 119 line of approach, for, 100 making pattern, for, 113, 119 making the cast, of, 120 materials for, 98 matrix for, 119 not indicated, 98 object of, 112 occlusal restoration, with, 118 pin for, 116 placing spruce wire for, 115 porcelain, construction of, 306- 311 applying of, 309 etching of, 310 finishing of, 310 grinding of, 310 matrix for, 306 pushing tcchnic of, 310 selection of, 308 toilet of, 310 530 INDEX Inlays — Cont 'd retention form for, 51 retention temporarily removed, 51 retention form of pattern, 115 saturating the model, 120 setting, 122 sponge gold as pattern, 119 sweating the contour, 118, 119 temperature of the model, 120 toilet for, 100 undercuts, filling of, 113 wax pattern, for, 113 Instruments, 17-20 angles in, 18 bin-angles in, 18 bur, 19 care of, 20 chisel, defined, 18 edge, 18 use of, 18 class name, II contra angles in, 18 cuts of, 314, 324 dental engine, use of, 19 exrjavators, 17 few in sight, 174 formula names, for, 18 gingival marginal trimmer, 18 hatchets, defined, 18 hoes, defined, 18 how named, 17 nomenclature, for, 17-20 plugger, point serrated, 19, 125, 126 amalgam, 143 rotating the, 126 size of, 126 rights and lefts, 17 sharpening of, 19 spoon, use of, 18 sub-class name, 17 sub-order name, 17 test for sharpness, 20 triple-angles in, 18 Instrumentation, lingual pit, 57 K Kaolin, formula of, 293 Labial outline: class three, 74 class four, plan one, rule for, 8G class four, plan three, 90 Length of sitting (children), 230 Ligature, 192 caution in use of, 192 cutting ends of, 193 how made, 192 knot in, 193 removal of, 193 Wedelstaedt tie, 193 Lime salts in solution, precipita- tion of, 181 Line angles, (see Cavity), axio-labial, class three, 76 axio-lingual, class three, 76 gingivo-axial, 77 Linen, 174 Lingual approach: advised, 135 class three, cohesive gold, 135 inlay illustrated, 105 Lingual outline : class three, 75 class four, plan one, 87 lower incisors, 87 Local anesthesia: anatomy, relatfd to, 277 cocaine in, 277 defined, 275 horizontal injection in, 285 infiltration in, 283 intra-alveolar in, 285 novocain, doses of, 279 novocain in, 277 pericemental injection in, 286 perpendicular injection in, 285 preparing solution for, 280 Einger's solution for, 281 suprarenin, doses of, 280 suprarenin in, 280 uses in dentistry, 276 M Mallet force: alone, 128 automatic, 128 INDEX 331 Mallet force — Cont'd hand, 128 power, 128 rule of, 128 Marginal bevel: angle of, 45 defined, 27 depth of, 45 necessity of, 27 Matrix: annealing of, 306 applying porcelain to, 309 material, for, 306 methods of forming, 306 porcelain inlay, 306 removal of, amalgam, 144 removal from porcelain, 310 taking the spring out of, 308 thickness of, 306 torn, 309 use of, class two, gold, 133 use of, in silicate filling, 162 use of, with amalgam, 141 Mouth mirror, use of, 175 N Novocain: sensitive dentine, 201 tablets, care cf, 281 Nitrous oxide, 202 O Objects in filling teeth, 29, 96 Occlusal defects, 48 Occlusal outline: class two, 66 class five, 94 Operative technic courses, 313, 322, 323, 324 Order of procedure: cavity, 29 for inlays, 99 Outline form: buccal pits, 55 class one, 48 class two, 59, 65 class three, 73 class five, 303 Outline form — Cont'd curving to the axial, class four, 86 defined, 34 distal superior cuspids, 91 for silicate, 151 inlays, class one, 101 class two, 103 class three, 105 large class one, 52 lingual pits, 55 porcelain inlays, 296 rule one of, 34 rule two of, 34 rule three of, 34 rule four of, 34 rule five of~ 34 rule six of, 34 rule seven of, 34 rule eight of, 34 rule nine of, 35 rule ten of, 35 step omitted in class two, 59 Over dessication, 71 Oxychloride of zinc, 146 Oxyphosphate of copper, 147 Oxyphosphate of zinc, 146 manipulation of, 147 spatulation of, 147 Pain, dental: alleviations of, 177 cold, causes, 177 divisions of, 177 foreign substances, causes, 178 patents in, 175 pericemental diseases, causing, 179 symptoms, aggravated, 177 treatment for, 177, 178, 179 Passive hyperemia of pulp, 178 Pins: placing for inlay, 116 soldered to matrix, 116 Tungston, 116 Planes of :i tooth: bucco-lingual, 28 332 INDEX Planes of a tooth — Cont'd horizontal, 28 mesio-distal, 28 Porcelain: advantages of, 294 basal body, 294 biscuit fuse, 294 build of layers, 294 cavo-surface angle for, 295 cement line in, 301 composition of, 293 contra-indications for, 295 dental, fused, 293-295 disadvantages of, 294 double step in, 302 enamel body, 294 fine grinding of, 294 flux, amount of, 294 foundation body, 294 high fusing, 293, 294 indications for, 295 lingual approach, class three for, 300 low fusing, 293 methods of fusing, 293 pigments in, 293 proximal approach for, 301 shrinkage in, 294 size of mass, 24 spheroiding of, 294 Potassium bromide, 202 Preventive dentistry, 180 Primary decay, location of, class three, 72 Prophylactic treatment, oral, 180 brushing, technie of, 186 importance of, 180 instructions to patients in, 186 oral hygiene, children, 229 Proximal Space, restoration of, 31 Pulp: canals, air in, 227 bent, 226 putrescent, 219 small, management of, 225 chamber, cleaning of, 228 chief idiosyncrasy of, 204 devitalization, causes for, 211 agents for, 212 Pulp : ■ devitalization — Cont 'd anesthetization for, 212 arsenic trioxide, for, 215 bacteria as related to, 211 care exercised in, 214 determining the method of, 212 high pressure for, 213 methods of, 212 technie of, 213 exposed, class one, 53 exposure, dangers in, class two, 65 exposure feared, class one, 52 infected with bacteria, 206 involved, class five, 95 lesions of, 177 normal, 204 partially devitalized, 218 peripheral nerve irritation, 212 preservers, 209 protection, 204-210 gutta percha in, 210 in class two, 66 in deep seated cavities, 207 indications for, 205 materials used in, 207 putrescence, 219-224 animal fats in, 221 autogenous, symptoms of, 222 autogenous, treatment of, 222 classes of, 219 closed, symptoms of, 222 closed, treatment of, 222 complicated, symptoms of, 223 complicated, treatment of, 223 defined, 219 open, symptoms of, 220 open, treatment of, 220 treatment of, general, 220 recuperative powers of, 204 removal of, 214-218 canal dressing following, 215 canal filling following, 215 discolorations following, 215 hemorrhage following, 215 pains following, 215 sensations are conveyed to, 195 stimuli, abnormal, 211 stimuli, normal, 211 traumatic injuries to, 211 INDEX 333 Pus in apical space, 179 " Putrefaction defined, 219 Pyorrhea alveolaris, IS-t R Eegional anesthesia: defined, 287 gasserian injection in, 288 infra-orbital injection in, 290 mental injection in, 290 palatine injection in, 292 pterygo-niandibular injection in, 288 spheno-maxillary injection in, 288 zygomatic injection in, 290 Eemoval of remaining decay: class one, 50 class two, 66 class three, 77 for cilicate, 154 inlays, 99 Resistance form: applied to filling material, 39 buccal pits, 55 class one, 49 class two, 62, 66 class three, 75 extension for, defined, 38 force to provide for in, 38 for porcelain inlays, 296 for silicate inlays, 151 importance of, 38 inlays, 99 class one, 101 class two, 103 class four, plan one, 106 involves a consideration of, 38 Retention angles for inlays, 99 Retention form: acute angles required in, 40 buccal pits, 56 class one, 49 class two, 62, 66 class three, 75 class four, 78-81 class five, 94 flat seats in, 40 inlays, class one, 102 Retention form: flat seats in — Cont'd class two, 103 class four, plan two, 107 for porcelain inlays, 296 for silicate, 153 little, in enamel, 41 maximum not required, 40 maximum required, 40 step as a portion of, 40 Einger^s solution, 281 Rubber dam: before ai^plying, 38 class one, 52 essential in filling with amalgam, 141 for silicate, 154 gingival side of, 191 holes, distance between, 190 holes, location of, 190 holes, size of, 190 invented by, 387 leaks in, 46 method of applying the, 191 number of teeth isolated with, 191, objections to use of, 187 occlusal side of, 191 placing of, 191 prevent leakage in, 192 removal of, 194 size and shape of, 190 thickness of, 189 S Secretions, abnormal, oral, 196 Separation: class two cavities, 59 for amalgam, 142 gutta-percha for, 165 immediate, 33 inlays, class two, 102 methods of, 32 preliminary, 33 soreness resulting from, 33 mechanical not essential, 176 use of, class two, gold, 133 Silex, formula of, 293 Silicate: amalgam, and, 171 334 INDEX Silicate — Cont 'd applied to prosthetic work, 172 cavity preparation for, 150 defined, 148 facing metal fillings with, 160 finishing the filling, 162 gold, and, 171 making the filling, 155 making the mix, 159 preparing the materials, 158 proper consistency, 159 time in mixing, 160 use of matrix, 162 Silieatization, defined, 148 Somnoform, 202 Sordes, consistency of, 183 Sordes, removal of, 183, 185 StaijQS on the teeth, 183 green stains, color due to, 183 injury to teeth, 183 removal of, 185 where found, 183 Step: area included, class two, 61 depth of class four, plan two, 87 distal superior cuspids, 91 forming of, 61 omitted in class two. 51 technic of cutting, class four, plan two, 88 T Teeth: compared, 270 order, changes in, 271 disregarding of, 272 of eruption, 270 Tin: amalgam and, 168 as a filling material, 166 cavity preparation for, 167 discoloration, amount of, 166 discoloration, by, 166 forms of, 167 gold and, 168, 169 history of, 166 in teeth of children, 167 methods of introduction, 167, therapeutic action of, 166 thermal conductivity of, 166 Toilet of cavity: best accomplished by, 45 class one, 51 class two, 67 defined, 45 for porcelain inlays, 297, 310 for silicate, 154 Tooth: brush, use of, 185 form, restoring of, 32 picks, 186 substance, saving of, 32 Tubuli, contents of, 195 W Wall: axial, class two, 62 class three, 77 defined, 23 for porcelain, class one, 298 for porcelain, class three, 299 buccal, class two, 62 distal superior cuspid, 91, 92 freshly cut, 88 gingival, defined, 23 gingival, class two, 66 gingival, class three, 77 gingival, class three, inlay, 105 inside, defined, 24 labial, 77 lingual, 77 lingual, axial, 62 lingual, class two, 92 occlusal, class five, inlay, 110 outside, defined, 22 pulpal, class two, 62 pulpal, defined, 22 sub-pulpal, defined, 23 weakened enamel, 38 Wide enamel margin, indicated, 46 Zinc: chloride of, 200 oxychlorate of, 146 oxyphosphate of, 146 sulphate of, 147 D29 1916 RK501 Davis Essentials of operative dentistry.