co^^^t^l^P'^^Jl^, 
 
 HX64072592 
 RK656 C531 P rosthetic articulal 
 
 RECAP 
 
 ii'ii:!; 
 
 -uo^thetic 
 Articulation 
 
 m 
 
 7 i'i ' )■ 
 
 George Voc^o Clapp.O.D.5. 
 
 l5MPI!'!liilira 
 
 (Hill 
 
 i ii lliiil'^'^P 
 
 
 il: i" ' 
 
 i 1 1^ 
 
 :HJi!| 1 i 
 
 If 
 
 liLlilii). 
 
 Hi. ' 1 I ' I • ■ 1 
 
 
 liiN'l!!!)!'^ Ill 
 
 lliiitii'iliiliilllijir 
 
 ' 'I 
 
 \.y.i\ 
 
 ,,., i!i It : I i':ii 
 
Columbia Winihtv^it^ c^. 
 in tfje Citp of j^eto Porfe (/ 
 
 ^cl^ool of Bental anb (J^ral ^urgerp 
 
 i^eference Eifararp 
 
 \ 
 
Digitized by the Internet Archive 
 
 in 2010 with funding from 
 
 Open Knowledge Commons 
 
 http://www.archive.org/details/prostheticarticuOOclap 
 
Prosthetic 
 Articulation 
 
 BY 
 
 George Wood Clapp, D.D.S. 
 
 wmMTTimmm^ 
 
 PUBI.ISHF.I) BY 
 
 THE DENTISTS' SUPPLY COMPANY 
 
 220 Wpist 42nd Sirilet 
 New York 
 
..I 
 
 Copyright 1914 
 
 BY 
 
 George Wood Clapp, D.D.S. 
 
PREFACE. 
 
 Tliis book is intended to make plain the principles of impression 
 taking and prosthetic articulation, but not to cover all applications of 
 those principles or to explain everv minute detail of technic. 
 
 What is here presented has been learned from many sources. I 
 wish to disclaim originality in connection with anything appearing in 
 the book, and to express my thanks to all who have aided in any way. 
 Especial thanks are due to three helpers, as follows: 
 
 ^Ir. S. G. Supplee taught me the method of taking impressions 
 and helped in preparing this presentation. He follows Dr. Greene's 
 method, but has effected important improvements in finishing the im- 
 pressions with the mouth closed and under normal biting stress. For 
 this reason I have called the method herein described the Greene-Supplee 
 method. Impressions finished in this way form excellent bases for re- 
 cording mandibular movements by Professor Gysi's methods. 
 
 Dr. J. Leon Williams has permitted the use of his methods of se- 
 lecting porcelain tooth forms. I believe these to be the first really scien- 
 tific methods of selecting tooth forms ever offered. By means of them 
 a person untrained in dentistry can select tooth forms better than has 
 heretofore been possible to even skilled dentists. 
 
 Professor Gysi's methods of articulation seem to me far superior 
 to any others. They demand more of the dentist in the early stages of 
 the work than other methods. Put they yield results not otherwise ob- 
 tainable. And, f)iice mastered, they really save time. 
 
 (Jysi articulators and Trubyte teeth are described and illustrated 
 hci-e because I believe them to be unapproached by any other products 
 in their respective lines. 
 
 The Authoj-. 
 
Table of Contents 
 
 PART I 
 
 Impression Taking 
 
 The Object in Impression Taking, 11; Nausea from Dentures, 11; 
 Impression Material, 12; Essential Steps in Impression Taking, 12; 
 Examining tlie Moutli, 12; Positions of Upper Buccal Attacliments, 
 14-15; Guidance by Facts Learned During Examination of the Mouth, 
 16; Chart for Artificial Dentures, 17; Impression Trays, 18-19; Warm- 
 ing the Compound, 2 0-21; Attaching the Compound to the Tray, 20-21; 
 Shaping the Compound for the Impression, 22-23; Shaping the 
 Compound for an Upper Impression, 24-27; The Upper Baseplate 
 Impression — Trimming the Bite, 28-35; Taking the Lower Baseplate 
 Impression, 3 6-3 9; Making the Baseplate Impressions into Trial Plates, 
 40-42; Recording the Bite, 43-45; Building up the Margins of the 
 Upper Impressions, 4 6-47; Massaging the Margins of the Upper Im- 
 pressions, 48-49; Condensing the Upper Buccal and Labial Attach- 
 ments, 50-51; The Antero-posterior Length of the Upper Impression, 
 52-53; Adapting the Upper Impression to the Palatal Soft Tissues 
 — The Effect of Adaptation, 54-5 7; Essentials of Comfort in a 
 Lower Denture, 58; Finishing the Lower Impression, 59; Taking Partial 
 Impressions, 60-61; Points to be Remembered in Refitting Upper Plates 
 or in Taking New Impressions, 62-63. 
 
 PART II 
 
 Selecting The Forms And Sizes In Anterior Teeth 
 
 Foreword, 67; The Origin of Face Forms and Tooth Forms, 6 8-69; 
 Harmony Between Facial Forms and Tooth Forms, 70-71; The Tem- 
 peramental Theory of Tooth Forms — The Application of these Discov- 
 eries to Porcelain Teeth, 72-75; Determining the Type of Face and 
 Teeth, 76-77; Modifications of the Square Type of Face, 78-79; Modifica- 
 tions of the Tapering Type of Face, 80-81; Modifications of the Ovoid 
 Type of Face, 82-83; Modifications of the Square Type in Teeth (Class 
 I), 84-85; Modifications of the Tapering Type of Teeth (Class II), 8 6-87; 
 Modifications of the Ovoid Type of Teeth (Class III), 88-8 9; Selecting 
 Anterior Teeth of Proper Sizes, 90-94; Determining Width of the Full 
 Set, 94-96; Selecting Teeth for Partial Cases, Bridges and Crowns, 97; 
 Selecting Lower Teeth, 97. 
 
PART III 
 
 Colors In Natural And Artificial Teeth 
 
 Foreword, 101; The Color Scheme in Natural Teeth, 102; How Color in 
 Natural Teeth was Studied, 103; Color Analysis, 104-108; How the 
 Colors are Placed in Natural Teeth, 109; The Vagaries of Color in 
 Natural Teeth, 110-111; Colors and Shades in Ordinary Artificial Teeth, 
 112; Colors and Shades in Trubyte Teeth, 113; Suggestions for Select- 
 ing Colors and Shades, 114; Table of the Colors in the Twentieth Cen- 
 tury Shade Guide, 115; Enamel Markings in Natural and Porcelain 
 Teeth, 116. 
 
 PART IV 
 
 Efficiency In Bicuspids And Molars 
 
 Foreword, 119; Functions of the Natural Bicuspids and Molars, 12 0- 
 121; Modifications of Natural Forms Necessary in Porcelain Teeth, 122; 
 What Constitutes Depth of Bite, 122; Five Stages of Wear of Natural 
 Teeth, 123; The Working Bite, 124-126; The Balancing Bite, 126-127; 
 Proper Formation of Cuspid Edges, 128-129; Cracking and Tearing 
 Power in the Bicuspids, 130-131; Cutting and Grinding Power in the 
 Molars, 132-133; The Impossibility of Grinding Improperly Formed 
 Teeth to Proper Bites or to Efficient Forms, 134-135. 
 
 PART V 
 The Selection Of An Articulator 
 
 Foreword, 139; Selecting an Articulator, 141; How the Jaw Movements 
 were Recorded, 142; Recording Opening and Closing Movements, 142- 
 143; The Importance of the Records of the Opening and Closing Move- 
 ments, 144-14 5; The Practical Importance of Correct Opening and 
 Closing Movements, 146-147; Recording Lateral Movements of Condyles 
 and Chin, 14 8-149; The Importance of the Records of the Lateral 
 Movements, 150-151; The Practical Value of the Lateral Movements, 
 152-157; The Influence of these Adjustments on the Movements of the 
 Bicuspids and Molars, 158; Permit Deeper Underbite of Lower Incisors, 
 159; Increase the Cutting Power of the Incisors, 159-160; The Gysi 
 Adaptable Articulator, 161-162; The Gysi Simplex Articulator, 163-165. 
 
PART VI 
 
 Mounting The Trial Plates On The Articulator 
 
 Measuring the Patient's Mandibular Movements, 169-179; Determin- 
 ing the Inclinations of the Lateral Path of the Condyle, 180-181; Meas- 
 uring the Inclination of the Downward Condyle Paths, 182-184; Pour- 
 ing the Models, 185; The Relation of the Incisor Point to the Condyles, 
 186-18 7; Mounting the Models on the Adaptable Articulator, 18 8; De- 
 termining the Horizontal Locations of the Rotation Points, 188; Attach- 
 ing the Models to the Gysi Simplex Articulator, 190-193. 
 
 PART VII 
 
 Articulating The Teeth 
 
 Making Wax Trial Plates, 19 6-197; Setting the Anterior Teeth, 198- 
 201; Relative Widths of Upper and Lower Anterior Teeth, 2 02-2 03; 
 Grinding Anterior Teeth to Form, 2 04-2 05; Setting up the Bicuspids 
 and Molars, 206-211; Automatic Articulation, 212-214; Grinding the 
 Teeth to Finished Articulation, 215-217; Trubyte Molar Blocks, 218- 
 219; Waxing Plates to Facilitate Pronunciation, 22 0; Investing the 
 Bicuspids and Molars, 220; Articulating the Vulcanized Dentures, 22 0. 
 
 PART VIII 
 
 Illustrations And Descriptions Of Teeth 
 And Tables Of Dimensions 
 
 Form 1 — Class 1 226-227 
 
 Form 2 — Class I. . . 228-229 
 
 Form 3 — Class 1 230-231 
 
 Form 4 — ^^Class I .23 2-233 
 
 Form 5 — ^Class 1 234-235 
 
 Form 1 — ^Class II 236-237 
 
 Form 2 — Class II 238-239 
 
 Form 3 — Class II 240-241 
 
 Form 4 — Class II 242-243 
 
PART I 
 
 Impression Taking 
 
THE OBJECT IX IMPRESSIOX TAKING 
 
 is to secure models over which to make dentures that exhibit 
 Relative stability in all positions of the mouth, 
 Efficiency in speech and mastication, and 
 Comfort to the patient. 
 
 Impressions finished with the mouth closed facilitate the making of 
 such dentures for the following reasons : 
 
 When the mouth is opened, the soft tissues on the buccal sides of 
 the upper ridge, and overlying the hard palate are distended. Im- 
 pressions taken with the mouth open yield models of the tissues in 
 distended positions. Dentures made over such models are often not 
 stable in all positions of the lips and cheeks. 
 
 When the mouth is open, the two prominent bands of soft tissue 
 on the buccal side of each upper ridge are distended backward from 
 their attachment to the ridge. For want of a better term I have called 
 this the ''posterior position." When the mouth is closed and at rest, the 
 anterior band occupies what I have called the ''^middle position," while 
 the posterior band seems to lose its individuality. 
 
 When the mouth is closed and the lips are thrust forward as in 
 whistling or seizing food, the anterior band occupies what I have called 
 the ''anterior position." The posterior band is rarely prominent in this 
 position. 
 
 The positions of these bands are shown in Figures 2-3-4. 
 
 If the buccal margins of the impression are trimmed to fit these 
 bands in the posterior position, the act of thrusting the lips out in biting 
 food is very likely to dislodge the upper denture. But if the margins of 
 the impression be trimmed to fit the attachments in the anterior position, 
 it will Ite impossible to dislodge the denture by any movements of the 
 lips. 
 
 Iiupix'ssions with properly trimmed margins can l)e taken only 
 while the mouth is closed and the upper and lower impressions support 
 each other under normal l)iting strain. The eU'ects of such trimming 
 are shown in the ilbistrations on page 15. 
 
 NAUSEA FKOM DENTURES. 
 
 Nausea is not caused by a properly fitting upper denture extending 
 too far backward, but by an imperfect fit of the posterior margin of 
 the denture, so that the soft tissues in moving up and down just touch 
 the denture, and a tickling sensation is caused, which results in nausea. 
 
 If an efiort is made to secure a fit by carving the model so that the 
 posterior margin of the denture j)rosses up into the soft tissues, nausea 
 may result. 
 
 If the impression })e finished witli the mouth closed and the im- 
 pressions under normal l)iting strain, the upper denture may be carried 
 as far l)ack as is reqnircd, witlif)ut causing nausea. 
 
 11 
 
IMPKESSIOX MATEEIAL. 
 
 Modeling compound is preferred for impression taking because : 
 
 It permits taking the impression in "stages." 
 
 Impressions may be finished with the moutli closed and under nor- 
 mal biting stress. This permits such adaptation of the dentures to the 
 soft tissues as is not otherwise possible, and seems to the writer the most 
 important advance in impression taking methods of recent years. 
 
 The dentist may know from the impressions whether or not the 
 dentures will fit the mouth. 
 
 Minor imperfections in the impressions can be easily corrected. 
 
 The impressions are built into trial plates. This expedites den- 
 ture completion. 
 
 ISTone of these procedures is practicable with plaster of paris. 
 
 ESSENTIAL STEPS IX IMFRESSIOIst TAKIXG. 
 
 Examining the moutli. 
 Trimming the upper and lower trays. 
 Shaping the compound in the trays. 
 Taking the working impressions. 
 Making upper and lower trial plates. 
 Finishing the impressions. 
 
 EXAMIXIXG THE MOUTH. 
 Figure Xo. 1. 
 
 Every mouth should he examined as to : 
 
 The character and extent of soft tissues overlying the hard palate. 
 
 Where the movable portion of the soft palate begins. 
 
 The character and extent of soft tissues in the ridges. 
 
 The location and strength of the muscular attachments on the 
 buccal sides of the upper ridge and both sides of the lower ridge. 
 
 The space between the tuberosities of the upper ridge and the rami 
 of the mandible when the mouth is closed. 
 
 Examinations should be made with the finger, with the mouth open 
 and closed. 
 
 All unusual conditions should be recorded on a chart. They may 
 aid in making the dentures or in satisfying the patient. 
 
 The chart used at the Gysi School of Articulation is reproduced 
 on page 17. It follows very closely Dr. McLeran's design. 
 
 12 
 
I'iK. 1. 
 Kxiiiiiiiilii;^ till- iiioiitli tiy tlii' Miil of the linger. 
 
 13 
 
POSITIONS OF THE UPPER BUCCAL^ ATTACHMEXTS. 
 
 Figures Xos. 2, 3, 4. 
 
 The darkened areas in Figure 2A show the two prominent bands 
 of tissue attached to the buccal side of the upper ridge, in the position 
 they occupy when the mouth is wide open. I call this "the posterior 
 position." Both bands are prominent. 
 
 The blackened area in Figure 2B shows the position occupied by 
 the anterior band when the mouth is closed and the tissues are relaxed. 
 I call this "the middle position." Under this condition the posterior 
 band seems to lose its definition and merge into the other tissues. 
 
 When the lips are projected, as in whistling or taking food, the 
 anterior band moves forward with its attachment to the ridge as a 
 center, to what I call "the anterior position." This position cannot 
 be easily shown in a model but its influence on the margin of an impres- 
 sion can be seen in Figure 31C. The posterior band does not seem to 
 be prominent in this position. 
 
 The Greene-Supplee method of impression taking allows both bands 
 to "trim" the buccal margin of the upper impression to all of their 
 positions, and then condenses the margin against the buccal tissues with 
 the mouth closed, the muscles relaxed, and the anterior band in middle 
 position. Dentures thus "muscle trimmed" are generally stable in all 
 positions of the mouth. 
 
 Figure 3A shows a model of a mouth with the tissues in the pos- 
 terior position and a metal plate adapted to it. Figure 3B shows a 
 model of a mouth made with the buccal tissues relaxed in middle posi- 
 tions, and the same metal plate on it. The space between the model 
 and the margin of the plate is noticeable. 
 
 Figure 4A shows a plaster impression of a lower jaw, as usually 
 taken. There is a great excess of material, which has distended the 
 tissues on both sides of the ridge. This distension prevents the adapta- 
 tion of the margins of the denture to the tissues at the base of the lower 
 ridge. Such adaptation is essential to comfort and efficiency in a lower 
 denture. 
 
 Figure 4B shows a lower impression taken after the Greene-Sup- 
 plee method and properly adapted to the tissues at the side of the ridge. 
 This impression is comfortable and relatively stable in all positions of 
 the mouth. 
 
 14 
 
Fig. 2. 
 
 Fig. 3. 
 
 Fig. 4, 
 15 
 
GUIDAXCE BY FACTS LEARI\TED DURI^s^G EXAMI]^ATI0X 
 
 OF THE MOUTH. 
 
 The upper denture should extend far enough back of the hard 
 palate so that its margin will make a valve with the soft tissu-es. In 
 cases of firm ridges in the front of the mouth, the denture need not 
 extend back onto the movable soft tissues. When the ridge in front is 
 very soft, the denture must extend farther Imckward to prevent being- 
 thrown down in biting. 
 
 Care must be taken not to displace the tissues in soft ridges. In 
 cases with very flabby ridges, special steps to prevent displacement 
 must Ije taken. Care must be taken also not to stretch the tissues on 
 the upper surface of the lower ridge, and cause pain. 
 
 The muscular attachments on the buccal side of the upper ridge 
 may be extensive or small, and strong or weak. The firmer the muscles, 
 the greater care must be taken to provide for their accommodation by 
 the margins of the denture. 
 
 The muscles on both sides of the lower ridge must be accommo- 
 dated. They are weak but effective in dislodging a denture. Perhaps 
 even more care is necessary here than in the upper denture. In cases 
 with narrow lower ridges, the lower denture may need to ride partly 
 on the muscles. But it must be evenly raised and lowered by the 
 muscles during movements Avith the mouth open, and not thrown out 
 of position. 
 
 Care must be taken that the upper tray and impression are so 
 trimmed between the tuberosity of the upper ridge and the ramus of 
 the lower jaw, that the denture shall not cause congestion of the tissues. 
 
 Spots of very hard tissue overlying the hard palate must be re- 
 lieved by laying tin of proper thickness over the model just before 
 vulcanizing. This applies especially to the tissues of the .median line. 
 
 16 
 
Chart for Artificial Dentures 
 
 (after that compiled by J. W. McLERAN. OMAHA. NEB.) 
 
 Name 
 
 Address. 
 
 MEMBRANE 
 
 ARCH AND VAULT. 
 
 INFLAMED HIGH. FLAT. OVAL. FRESH. 
 
 REGULAR 
 
 Firm. 
 
 PERMANENT. 
 
 FLABBY 
 
 SUBMUCOUS 
 
 TISSUE. 
 
 ABNORMAL 
 
 MUSCULAR OR 
 
 GLAND. ATTACHMENT. 
 
 LATERAL 
 CONDYLE PATHS. 
 
 FORWARD 
 CONDYLE PATHS. 
 
 ^ ^ RIGHT 
 
 BONY PROMINENCE. 
 
 UNDERCUT. 
 
 ROTATION POINTS OUT 
 FROM CENTER 
 
 Right at No. 
 
 SELECTION OF TEETH. 
 
 M EASUREMENTS 
 
 UPPER 
 MOULD 
 NUMBER 
 
 -MM. LENGTH OF CENTRAL INCISORS. 
 
 -MM. Combined Bite and Shut 
 MM. Rioge Lap. 
 
 MM. Width 6 Anteriors 
 
 -MM. Width Full Set. id. 
 
 MM. I 
 
 
 MM 
 
 LOWER 
 
 
 MOULD 
 
 
 
 
 MM. 
 
 
 Shade Upper Central- 
 
 Kind OF TEETh 
 
 l''iKlir« ^ 
 
 17 
 
IMPKESSIOis^ TRAYS. 
 
 The trays here illustrated are those designed by Dr. Greene. Those 
 designed by Mr. Supplee are more convenient in some respects. Other 
 trays can be used by proper trimming, and are used by some followers 
 of this method. 
 
 Trim the upper tray for antero-posterior length first. If the alveolar 
 ridge in the anterior portion of the upper jaw was found to be hard, 
 trim the center of the posterior margin to rest on the soft tissues imme- 
 diately posterior to the margin of the hard palate. If the ridge was 
 soft, trim the tray to extend back a little way onto the tissues which can 
 be seen to vibrate when the patient opens the mouth and says "Ah." 
 
 Bend the posterior margin of the tray to lie in easy contact with the 
 tissues from the ridge on one side to the ridge on the other. 
 
 Trim the buccal margins of the tray until they ''clear ' all muscular 
 attachments, so that the patient cannot bring any pressure on the tray 
 by lip or cheek movements. Bend these margins so that they follow 
 the outer sides of the ridge, about Ys inch away. 
 
 The upper tray, as thus trimmed, will be "shorter" in all direc- 
 tions, than the impression is to be. This permits manipulation of the 
 margins of impression material, where they extend beyond the margins 
 of the tray. 
 
 Trim the height of the "heels" of the buccal margins according to 
 the amount of free space between the tuberosity of the upper jaAv and 
 the ramus of the lower. 
 
 Trim the labial and buccal margins of the lower tray until it can- 
 not be dislodged by lifting the cheeks and lips. 
 
 Trim the inner margin until lifting the tongue does not dislodge it. 
 
 The tray as thus trimmed may be extremely narrow. This need 
 not cause apprehension. The only function of a lower tray is to carry 
 the compound to place. 
 
 Bend the handles of both trays out of the way of the lips. 
 Dry both trays to receive compound. 
 
 18 
 
Fig. 6 
 
 A. A Greene tray, untrimmed for lielglit or length and not tittt'd to tlie curvature of 
 tbe vault or ridge. This tray is likely to distend the tissues. It locates the posterior 
 margin of the denture without reference to the conditions in the mouth. It prevents 
 adaptation of the impression margins at all the borders. 
 
 B. An excess of compound arranged with more care tliaii is custoin.-iry, in the tray 
 shown in "A." Note the thickness of compound at the posterior margin of the trny. 
 
 C. The impression taken with the tray and compound shown in "A" and "B." Tiiis 
 compound was evenly hot throughout the mass. The posterior margin of the tray has 
 come into contact with the tissues at two spots, while the center of this margin was too 
 far from the tissues. This iniijression was taken witli the mouth open and without 
 "muscle trimming." 
 
 Fig. 7 
 
 A. The same tray as is Hhown in OA, but trimmed for length, and bent to easy 
 contact with the tisHues of the vault at ttie posterior margin. The buccal and labial 
 tnargins trimmed to "clear" all muscles and to follow tli(! curvafui-e oC (lie ridge. 'I'his 
 tray permits maniiiulation of all lmt)resslon margins. 
 
 B. About the right amount of (•om|)ouMd, projierly arranged in tray. Note tliat 
 tbe compound does not extend rjulte to tlie rear margin of tlie tray iu tlie median line. 
 
 C A basefilate Imiiresslon from the same mouth as the irnpiessioii In fiC. The 
 DiaMHage Illustrated In i'"lg. 17 has been applied. This inroiiiiilcic iiiipicssiou is better 
 than the supposerlly comidete one in l''lg. (!<'. 
 
 19 
 
WAEMIJSTG THE COMPOUND. 
 
 rigure jSTo. 8. 
 
 Less than half a sheet of compound is usually sufficient for an 
 upper impression of ordinary size. The more skillful the operator the 
 less compound he requires. 
 
 The compound is to he immersed in hot but not boiling water, and 
 heated until the sharp margins begin to round down. It should then 
 be kneaded until the mass is of equal softness throughout. 
 
 If the fingers are kept wet, the hot compound will not stick to them. 
 
 If the vessel containing the water is heated from below, a piece of 
 blotter may be laid in the bottom to prevent the compound sticking to 
 the dish. If the blotter extends above the water on two sides, it will 
 be useful in lifting the compound. 
 
 Electric heaters which heat the upper surface of the water more 
 than that in the bottom of the dish may be had, and are advantageous. 
 
 Form the soft compound into a smooth l^all. 
 
 ATTACHING THE C0MP0U:N^D TO THE TEAY. 
 Figure iSTo. 9. 
 
 Heat one side of the compound above a tiny gas flame or an alcohol 
 flame until it sizzles. 
 
 Attach the sizzling side to the center of the dry upper tray. 
 
 20 
 
Less than half a sheet of (•onipound is reciuired for an upper impression of niedluni 
 size. It is heated in water of a temperature of about 160° until the sharp margins be^'in 
 to round. It should be kneaded until it is an even softness throughout the mass and 
 shaped into a ball. 
 
 rig. ;• 
 
 'JIh! upper ImpreKsioii tray Is dried. One siih- of the ball of ciiiripipiiiid is heated over the 
 flame until It hIz/Jch uikI Im at onee attached to the citiiU-i- of the vault of the drii^d tray. 
 
 21 
 
SHAPmO THE COMPOUND FOE THE IMPRESSIOK 
 Figure JSTos. 10 and 11. 
 
 With wet fingers quickly shape the soft compound into a mound in 
 the center of the tray, a depression all along where the alveolar ridge 
 will come, and a relatively high ridge to go up under the lip and cheeks. 
 
 Do not allow the compound to extend quite to the posterior border 
 of the trav. 
 
 The compound is shaped as described above to cause it to come first 
 into contact with the tissues as shown in Figure 11. It should strike 
 first the centre of the vault of the palate, and the labial and buccal sides 
 of the ridge, and flow from both directions to the alveolar border. In 
 this way, distortion or displacement of soft ridges is avoided and perfect 
 impressions obtained. 
 
 When the ridge is extremely soft, that portion of the working im- 
 pression which came into contact with the soft ridge tissues may be 
 cut away, very soft plaster flowed into that portion of the tray, and the 
 impression replaced in the mouth. In this way, impressions of very 
 soft ridges tnay be obtained. 
 
 Care must be taken not to push forward the ridge in the anterior 
 13art of the mouth, or pain mnj result from pressure on the blood ves- 
 sels and nerves passing through the anterior palatine canal in the 
 median line, just back of the incisors. 
 
 When taking the lower impression, the tissues on top of the ridge 
 must not be stretched or pain will be caused. 
 
 22 
 
ViSX. 10 
 
 Willi wet tiiifrors sli:i|ic the ball of compound to iireseiit a trough where the alveolar 
 ridge will come, a higli ridge to go up under the lip and cheeks and a mound in the 
 center of the vault. I>o not allow the compound to extend (luite to the posterior margin 
 of the tray. 
 
 Tin- compound Is Intendr-d t 
 and laldnl sides of the ridge and t^ 
 Hideti. 'i'lils prevents condensation 
 buccal margins of the tray are low 
 
 Fig. n 
 
 sirikc lirsl I Ik 
 
 center of the vault an<l on the buccal 
 Ib.w tri the crest of the riilge by [ii-essure from both 
 or disphiicment of even soft ridges. Note that the 
 ■r than the margins of the impression will be. 
 
 23 
 
SHAPING THE COMPOUND FOR AN UPPER IMPRESSION 
 
 • — Continued. 
 
 Figures Nos. 12 and 13. 
 
 Draw the compound into a hill which shall come in the center of 
 the vault. If there is more compound than is likely to be required, it 
 can be pinched off as shown here. Keep the compound from extending 
 to the posterior margin of the tray. 
 
 Warm the ''hill" of compound over a gentle flame so that its top 
 shall round down, but shall still present a higher cone than will 1)e re- 
 quired by the formation of the vault. 
 
 24 
 

 ^ 
 
 ^^ 
 
 
 K' 
 
 
 Fig. 12 
 
 Shape the (■ompduiul iiitu tlie fdrin of a hill in the center of tlie tray. Keep it warm dvcr 
 
 tlie tlanie and plmh oft' any excess at the top of the hill. 
 
 Kit,'. 13 
 When tlu- coiiipoiind has been propci-l.v shajiod and the c.m'css pinched off, warm the 
 top of the liill over the flame so that it i-aii he shaped down to a smo(j|h surface. Then 
 I>aHs the entire Iniprr-ssirin siirfaic of tlic '(iiiipoiiiid ahovc a small llamc, so tliat tlic 
 Knrf;i<'e nia.v be rendered softer Iharj I lie iinderl \ In;,' portions. |)i|i IIm> Ir.iy and idmiHinnd 
 into hot water to erjnalixe the heal. 
 
 25 
 
SHAPI:NG the COMPOU^^D for A'N upper IMPRESSIOK 
 
 Eiffures jSTos. 14 and 15. 
 
 '^fci" 
 
 When tlie top of the "hilF' of componnd has been properly warmed 
 over the flame, dip the entire tray into hot, but not boiling water, to 
 equalize the heat and avoid burning the patient. 
 
 When the heat has been equalized in this manner, it is desirable 
 to heat the surface of the compound more than that which lies deeper in 
 the tray, so that the surface shall be in condition to ^'flow" easily and 
 shall be supported by the slightly cooler compound between what may 
 be spoken of as "the surface layer" and the tray. 
 
 This additional heating of the surface compound may be effected 
 by turning the tray so that the palatal surface is downward and in this 
 position immersing the margins of compound and the "hill" in water, 
 of a temperature about 160 degrees, but not immersing the tray. 
 
 The tray should then be quickly inserted into the mouth, since the 
 surface will be in the finest possible condition for impression taking. 
 
 26 
 
Fig. 1-i 
 It is a principle of tliis method of Impression taking tbat the surface of the compound 
 shall be as soft as may be without changin.i; form, while the underlying portions of the 
 compound shall be slightly cooler apd firmer. 
 
 When the surface has been heated as described and the heat has been equalized, 
 the tray may be held with the impression side down and the hill and margins of the 
 innpression immersed for a little in hot water. The tray should not be immersed. 
 AVhen it is removed, the surface should be just ready to flow, while the underlying 
 portions of compound will not be (|uite so soft. The tray is then quickly inserted in 
 the mouth. 
 
 27 
 
THE UPPER BASEPLATE IMPEESSIOX. 
 
 Figure I^o. 15. 
 
 Tlie tray is passed into the mouth and pressed about half way 
 "home" with a slight wave-like, side to side motion. The compound 
 on the buccal and labial surfaces of the ridge is pressed upward and 
 against the ridge by putting the finger into the mouth as here shown. 
 
 This carries the compound against the ridge and higher than the 
 margins of the impression will finally be. It makes possible the proper 
 trimming of the margins by the muscles. 
 
 If the compound is not carried up by the finger, the margins of 
 the impression may be deficient, and much of the value of this method 
 may be lost. 
 
 28 
 
('iin-y\lii; tlio coiiiiioiiimI ii|< iiiiilci- tln' lip nnd rlicck.s to iiism-c siillicifiilly lii;,Mi rims. 
 
 29 
 
THE UPPER BASEPLATE IMPRESSI0:N'— Continued. 
 Figure JSTo. 16. 
 
 While the cup is being pressed ^'home," have the patient draw back 
 the lips as in hearty laughing and then push them well out, as in the 
 position for whistling. These motions of the cheeks and lips call into 
 action the muscles which extend over the margins of the impression, 
 and enable them to shape the compound to forms which will accom- 
 modate their movements without dislodging the denture. That is, 
 the muscles ''trim" the margins of the impression. The importance of 
 this will be more apparent, later. 
 
 The necessities of illustrating the action of the upper lip, required 
 the dentist to stand well back for this picture. In practice, it is im- 
 possible to stand back in this way and hold the hand so far back with- 
 out rocking the impression, which will cause the denture to rock also. 
 
 The dentist must stand in front of the patient, must see that his 
 finger extends well back under the tray, must press the tray up at the 
 back first, and when it is in position, must hold it firmly against the 
 palate, with just the slightest forward pressure to carry it toward the 
 highest part of the vault. 
 
 The patient will probably make the lip motions more intelligently 
 if the dentist instructs the patient how to make them before commencing 
 impression taking, and if he makes them when he directs the patient to. 
 
 30 
 
Patient "musck'-trlriiinliiK" upper imprcssiDii by Hi) iiiovciiH.'iits. 
 
 31 
 
THE UPPEK BASEPLATE IM PEE SSIOJN'— Continued. 
 
 Figure jSTo. 17. 
 
 Wlien the compound was pressed up under the lip and cheeks as 
 shown in Figure 13, it was carried higher than the margin of the im- 
 pression will be, in order that it might be trimmed by the action of the 
 muscles. 
 
 The motions of the cheeks and lip shown in Figure 17 trimmed 
 the margins of the comjDOund, by turning it outward and downward 
 where it interfered with their movements. In doing this, they fre- 
 quently turn it too far downward, and it is necessary to press it inward 
 against the tissues and carry it again a little upward. 
 
 These ends can be achieved by applying the thumb and forefinger 
 ■oi the left hand to the cheeks and lip, heloiv the upper margin of the 
 tray, and giving them a slight rotary motion, with gentle inward pres- 
 sure. Care must be taken not to pull downward. The tray is mean- 
 time held firmly in position by the finger of the right hand in the vault. 
 
 This massage will also continue the downward movement of the 
 excess compound and turn it beneath the tray. 
 
 When this massage has been completed, an impression should be 
 ;sufiiciently well adapted to the vault of the mouth and the surface of 
 the ridges so that it will not rock. If it rocks, it must be corrected or 
 remade, since the rocking will invariably lead to trouble. 
 
 As a general thing, an impression which has been carefully taken, 
 this far, will have also enough of what Dr. Greene calls "sticktion" to 
 permit its use in the later stages of impression taking. 
 
 N 
 
 32 
 
Fit,'. 17 
 I"ir>t iii;iss;ijrf, Ix'Idw npiicr iii;ir;;iii (if tray. 
 
 33 
 
TRIMMK^^G THE UPPER BASEPLATE IMPRESSION 
 
 Figures N^os. 18 and 19. 
 
 The margins of the impression, as it first comes from the mouth, 
 are generally thick enough to distend the tissues of the cheeks and lips, 
 a condition which must be avoided. 
 
 Trim the buccal and labial margins after the manner shown in 
 Figure 'No. 18, until they are of the thickness desired in the finished 
 denture, and give the patient's face the desired expression. Care should 
 be taken not to alter the form of the margins or to break the compound. 
 If the compound is broken in trimming, no effort should be made to 
 repair it until after the bite is taken. Efforts to repair it before that 
 stage is reached, usually result in spoiling the impression. If the 
 posterior margin of the impression cup was exposed in taking the im- 
 pression, it should be bent backward out of contact with the tissues. 
 The exposed area will later on be covered with compound. 
 
 In trimming the labial and buccal margins, much care should 
 be taken to restore the expression, especially in the region of the canine 
 eminences. Figure 19 shows a patient without trial plates and again 
 with properly built trial plates. 
 
 The posterior margin of the impression should be trimmed to the 
 exact length desired in the finished denture. When the alveolar ridge 
 in front is hard, the denture will extend on to the relatively immovable 
 soft tissues immediately posterior to the hard palate. When the an- 
 terior alveolar ridge is soft, the denture will extend back onto the mov- 
 able soft tissues. 
 
 The "heels" of the buccal margins should be trimmed thin, so that 
 they will not distend the cheeks, and so that they can be warmed and 
 massaged into the desired contact with the tissues. 
 
 The possibility of softening the margins and adapting them by 
 pressure with the mouth closed and the impressions supported in place 
 under normal biting strain, constitutes the great advantage of the 
 G-reene-Supplee method of impression taking. The impression is now 
 laid aside until the lower impression has been taken. 
 
 34 
 
Trimming impression to proper buccal and labial thickness. 
 
 Fl(?. 19 
 By properly flllln;? out and "llftInK" the tlHsues, great changes In the expression 
 
 can be effected. 
 
 35 
 
TAKIXG THE LOWER BASEPLATE IMPRESSIOK 
 
 Figures Nos. 20 and 21. 
 
 Soften the compound in hot bnt not boiling water, in the same 
 manner as for the npper impression. Form it into a roll about half as 
 thick again as a lead penciL Lay it aside to cool slightly while drying 
 the tray. Heat one side of the roll over a small flame until it sizzles. 
 Attach this side to tlie dry tray. Pinch oft" the excess of compound at 
 the ends of the tray. Llold the tray with the compound side up, and 
 immerse the tray but not the compound, for an instant in cold water. 
 This will cool the tray and the compound next to it and cause the cooler 
 portions of the compound to act as a tray to keep the softer portions 
 from getting too far out of place. 
 
 Soften the surface of the compound over the flame and then dip 
 the compound but not the tray, into hot water to equalize the heato 
 It is then ready for prompt insertion into the mouth. 
 
 For lower impressions, the compound should have l^egun to cool 
 a, little on the side next to the tray as mentioned above but should be 
 ready to "flow" on the surface. If the compound be too soft all the way 
 through, the tray is likely to come into contact with the tissues and 
 cause muscle strain and an imperfect impression. 
 
 If the tray comes into contact with the tissues, it must be cut away 
 at the exposed points until it is lower than the adjoining compound. 
 
 36 
 
Vig. 20 
 
 as th 
 
 Shape a roll of compound about as thick again as an ordinary lead pencil and as long 
 he arcli of the lower tray. Lay it aside to cool a little while drying the tray. 
 
 Wiiriii one side of the roll till it sizj 
 I'XiftHH cdiiipoiinil Jit th<' ends. Snflcii the 
 fldiiie until It Ih nearly rejidv to tluu, |)ip 
 'ouipouiid next to It, Into liot walir l<> !■■ 
 the mouth. 
 
 the 
 |ii;ili 
 
 il :itt:i< 
 
 ssidii s 
 
 iprcssii 
 
 the Ik 
 
 Il It l< 
 iirCiU'c 
 >ii siirl'; 
 
 ■Ml. It 
 
 IIm' 
 if II 
 
 ml not 
 Ihc'ii re 
 
 lr;iy. I 'in 
 ipoiiiid iiv 
 
 the tr:iv 
 •Mdy to pi 
 
 ■h oir 
 •r I he 
 <\- I lie 
 
 37 
 
TAKII^^G THE LOWER BASEPLATE IMPRESSION". 
 
 Figure 'No. 22. 
 
 Place the tray and compound in the mouth and locate them di- 
 rectly over the ridge, or a little to the lingual of the anterior part of the 
 ridge. When they are properly in place, have the patient open the 
 mouth as wide as possible. Stand in front of the patient, place a fore- 
 finger on the bicuspid region of each side, and make very light pres- 
 sure on the tray. If the tray was placed a little to lingual of the ridge, 
 this pressure can be slightly forward as well as downward, which is 
 an advantage, because it forces the excess compound to flow to the 
 lingual side of the ridge, where it can be easily controlled. 
 
 Change the position of the hands so as to bring the first and middle 
 fingers of the left hand on the two sides of the tray in the bicuspid 
 region, and hold the tray steadily in place with very light pressure. 
 Ask the patient to close slightly, so as to relax the muscles. Reach 
 under the left wrist, and with a thumb and finger of the right hand 
 make a quick, light massage on the outside of the cheeks in the region 
 of the bicuspids and molars. 
 
 Place the index finger of one hand on each side of the tray in the 
 bicuspid region, and, if the patient is sufficiently intelligent to co- 
 operate with your eft'orts, ask her to make one effort to SAvallow. If the 
 patient is not intelligent and might bite the fingers, ask her to raise 
 the tongue a little. The contraction of the muscles in swallowing will 
 begin the "trimming" of the compound on the lingual margin of the 
 impression. 
 
 Remove the impression from the mouth and trim away all surplus 
 compound until the impression is smaller than the lower denture is to 
 be. This impression is intended only to lie on top of the ridge and 
 serve as the base for a trial plate. Ho corrections should be attempted 
 at this time unless the impression rocks. If the impression rocks, it 
 should be corrected by warming the entire ridge surface evenly, re- 
 placing in the mouth and holding down with light but firm pressure. 
 If this does not correct it, a new impression should be taken. 
 
 38 
 
Klg. 22 
 Lo<ate the lower tray and coinpoiiiKl directly over or a little to the lingual of the ridge. 
 
 .S9 
 
MAKING THE BASEPLATE IMPEESSI0:NTS INTO TRIAL 
 
 PLATES. 
 
 Figures Nos. 23 and 24. 
 
 The working impressions are made into trial plates by adding a 
 roll of componnd to each and trimming it to indicate the positions to 
 which the teeth are to be set. 
 
 Shape a roll of compound a little larger than was used for the 
 lower impression, and as long as the lower ridge, from heel around to 
 heeL Heat the middle portion of one side until it sizzles and attach it 
 to the anterior portion of the ridge of the lower tray, leaying the ends 
 free. Direct the heat of a tiny flame between the tray and the unat- 
 tached portion of the roll, and when each end is hot enough, attach it to 
 the tray, taking care to keep the hands moist during the work. 
 
 Shape the occlusal edge of the roll to the form of a wedge. Soften 
 the wedge deeply, so that it can be moulded, and quickly place the trial 
 plate in the mouth. Either of two methods can now be followed. 
 
 If a Gysi Adaptable x4rticulator is to be used, press the Horseshoe- 
 plate which comes with the articulator, into the lower trial plate until 
 its labio-incisal margin is about 1/16 inch below the level of the edge 
 of the lip, when at rest, and the occlusal surface of the heel is on a level 
 with the upper surface of the tulierosity at each posterior termination 
 of the lower ridge, or 
 
 Press the compound of one side to the same level with a short, 
 straight knife blade, like that of some plaster spatulas. Then invert 
 the trial plate on a wet piece of glass and by pressure shape the other 
 side to the same level as the pressed side. Trim away excess compound. 
 
 Trim the arch of the lower trial plate to make plenty of room for 
 the tongue, so that the denture will not be lifted by the tongue being- 
 crowded. 
 
 Trim the buccal margins to make the ridge about as thick, from 
 tongue to lip and cheek, as the teeth will be. 
 
 40 
 
Fig. 2:;. 
 Attaching tlie roll tiniily to the baseplate iiiiiiressidii t<< I'onn the trial plate. 
 
 I'ig. •_'!. 
 
 A. Lower trial jilato with horseshoe phite pressed into it. I!. Lower trial plate with 
 ridge properly forilU'd without use of liorseshoe plati>. Note the wide space lor tonmic, 
 the shortened "heels", and the Corni of ridge. 
 
 41 
 
MAKIN^G THE BASEPLATE IMPRESSIONS INTO TRIAL 
 
 PLATES— Continued. 
 
 Attach a roll of compound to the ridge of the upper impression 
 in like manner, shape it to the form of a wedge, place it in the mouth 
 with the lower trial plate in position, and have the patient close the 
 jaws until the lips nearly touch in repose. 
 
 Most patients, when instructed to bring the jaws together till 
 the lips touch, stretch the lips but do not bring the jaws close enough 
 together. When they do this, the lower jaw is nearly always in the 
 retruded position. When a patient does this, remove the upper trial 
 plate from the mouth and trim it to the impression made in its occlusal 
 surface by the cold lower trial plate. Cut away the "heels" of the 
 ridges of both trial plates as far forward as to where the middle of the 
 second molars will come. Warm the occlusal surface of the upper over 
 the flame, dip into hot water to equalize the heat, replace in the mouth, 
 and have the patient relax all muscles and then close the jaws until the 
 lips touch lightly in repose. 
 
 This determines the correct heights of the trial plates, equalizes 
 the pressure on both sides, which is most important, and practically 
 insures a correct bite. 
 
 For some years, I have advocated the method of shaping the occlu- 
 sal surface of the upper trial plate to be parallel to a line drawn on 
 the face, from the ear to the nose. Two or three years ago Dr. Ulsaver 
 and I conducted some experiments which satisfied us that the location 
 of the heels of the occlusal plane could be moved upward or downward 
 somewhat without affecting the articulation or efficiency of the teeth, 
 and sometimes with mechanical advantage. We learned later that Pro- 
 fessor Gysi had conducted similar experiments and arrived at similar 
 conclusions. We have lately followed Mr. Supplee's modification of 
 the method, as described above, and find it easier and quicker. 
 
 42 
 
EECOKDING THE BITE. 
 
 Figures Xos. 25, 26, 27, and 28. 
 
 "When correct biting relations have been established bj the methods 
 just suggested or any others the dentist may prefer, it is important to 
 register them in such way, that the patient will be compelled to bite cor- 
 rectly during the finishing of the impressions, since a wrong bite at that 
 time may destroy all accuracy in the fit of the impressions and subse- 
 quently of the dentures. 
 
 Dr. Greene's method of doing this is probably one of the best. It 
 is to cut a notch in the occlusal surface of a separate trial plate at the 
 median line, and one at each side, in the bicuspid region. The occlusal 
 surface of the lower trial plate is then dried and a little soft compound 
 added to it, opposite the notches. While this added compound is still 
 soft, the patient is caused to bite in right position. This forms three 
 eminences on the lower trial plate, corresponding to the depressions in 
 the upper, and compels the patient to bite in right relations during sub- 
 sequent proceedings. Mr, Supplee has shortened the work and facilitated 
 accurate bite taking by making the impressions into trial plates and 
 using tlic notclies in the same way. 
 
 This method demands that the bite be accurate when the notches 
 are filled with compound, or it will continually thereafter be wrong. 
 
 The dentist who uses the Gysi Adaptable Articulator has the most 
 nearly positive method of determining the correct closure that I know 
 of. If the Incisor Path Register is used in connection with the Horse- 
 shoe plate, 1)lackened in front, the point of the Register will trace, in 
 nine cases out of ten, a round pointed pattern as long as the jaw is 
 protruded, and a sharp pointed pattern when the jaw is in its resting 
 position. This record alone is so important as to justify the use of this 
 articulator, for dentures and extensive bridges. 
 
 43 
 
\ 
 
 Fig. 25. 
 Cutting notches in the lower trial plate to record correct biting relations. 
 
 Fig. 26. 
 
 On the left, the trial plates as bitten together in the mouth. The other two illustrations 
 
 show the elevations on the upper trial plate and the notches in the lower. 
 
 Fig. 27. 
 
 The festoons in the upper trial plate, shown on the right, help in correctly replacing 
 the trial plates. 
 
 The vertical marks on the left are good, while the sloping marks are false and 
 misleading. (Photograph by Prof. Dr. Gysi.l 
 
 44 
 
liO'-onlllig the; l»itr. I)y iiic;iiis of tin- (Jysl Iii<-lsi>r riitli Iti-;,'istcr aud Ilorscslioe J'late. 
 
 45 
 
BUILDD^G UP THE MAEGINS OF THE UPPEK 
 
 IMPEESSIOE'S. 
 
 Figures ISTos. 29 and 30. 
 
 When the trial plates have been shaped to satisfactorily support 
 each other with the mouth closed, and the bite has been taken and regis- 
 tered, the upper impression may be finished under normal biting strain. 
 This finishing is accomplished by modifying the margins of the impres- 
 sion to conform to certain positions of the tissues. 
 
 The first step in finishing the impression is to make sure that the 
 margins are high enough. The experienced operator will be able to 
 detect low places in the margins of the impression at a glance, but the 
 inexperienced operator cannot do this. For his first cases, he will do 
 well to add compound all along the margins by heating a stick of com- 
 pound and building onto the impression as shown in Figure ISTo. 29. 
 He should quickly insert the impression in the mouth, the lower being 
 alwaj^s in position, have the patient close in correct bite and perform 
 the laughing and whistling motions, and immediately afterward apply 
 gentle massage as illustrated in Figure 31. 
 
 As soon as the margin is high enough all around and has been 
 "muscle trimmed" and massaged, the entire buccal and labial margin 
 should be warmed beside a small flame, until the compound is soft 
 enough to permit adaptation by massage, but not soft enough to change 
 its form. The impression should be quickly inserted in the mouth, the 
 patient caused to again make laughing and whistling movements, and 
 the compound massaged into better adaptation to the buccal and labial 
 tissues in the manner shown in Figure 31. 
 
 46 
 
Fig. 29. 
 
 Tracing on compound from a stick softened over the flame to repair broken margin. 
 
 Compound for building up margins is traced on the side of the impression 
 
 in contact with the tissues. 
 
 Fig. ;jo. 
 
 Softening the margins without clianging their form. 
 
 47 
 
MASSAGING- THE MAEGIES OF THE UPPER IMPRESSIOI^. 
 
 Figure l^o. 30. 
 
 Wiien the upper trial plate, with the buccal aud labial margius 
 softened as described, has been put into the mouth, and the lip and 
 cheek movements have been made with the mouth closed and the trial 
 plates supporting each other, and the j)atient has relaxed all muscle 
 tension, the softened margins are adapted to the buccal tissues by mas- 
 sage. To effect this massage, the finger and thumb are applied first to 
 the cheeks and then to the lip, on the level of the softened margins. A 
 gentle inward pressure is exerted against the tissues, and the thumb 
 and finger are given a slight rotarv motion. 
 
 This massage is not intended to carry the compound of the softened 
 margins either up or down, or to change its form, but merely to press 
 the already formed margins inward against the buccal and labial 
 tissues, while the attachments to the buccal side of the ridge are in 
 what I have called ''the middle position." During the laughing and 
 whistling movements of the cheeks and lip, these attachments have 
 travelled back and forth under the margin of the compound and have 
 made a space for themselves. When the patient has relaxed all mus- 
 cular tension, the massage will adapt the margins of the impression to 
 these attachments in "the middle position." EoUowing such adapta- 
 tion, the denture will be stable in all positions of the lips and cheeks. 
 Similar light massage will be applied to the margins of the lower trial 
 plate. 
 
 Some ideas of the possibilities of conformation by massage may 
 be gained from Figures 31 and 32. 
 
 48 
 
I • 
 
 r 
 
 ' 
 
 via. ■■;<). 
 
 Flniil iii!iss;iK<' "f iii:ir;:iiis <>{ iipiicr iniprcssidii. iihovr tlic Ir.-iy. 
 
 49 
 
CONDENSING THE UPPER BUCCAL AND LABIAL 
 ATTACHMENTS. 
 
 Figures Nos. 31 and 32. 
 
 It is difficult to overstate the advantages which result from proper 
 adaptation of the margins of the impressions to the buccal and labial 
 soft tissues, in what may be called "the middle position." The several 
 impressions from one mouth shown in Figures Nos. 31 and 32 may help 
 to make the possibilities of such adaptation clear. 
 
 Figure 31A is an impression taken with a poorly adapted tray, 
 with an excess of compound, and with the mouth wide open. The 
 formation of the margin shows the buccal attachments to be in the 
 posterior position. 
 
 Figure 31B shows an impression of the same mouth, taken with a 
 properly adapted tray, a correct amount of compound, and "muscle 
 trimmed" with the mouth open. The effect of the muscle trimming on 
 the form of the buccal margins is very marked. 
 
 Figure 31C shows an impression of the same mouth which has 
 been "muscle trimmed" with the mouth closed under normal biting- 
 strain, by carrying the buccal attachments into the "anterior position" 
 in the whistling movement, but without adaptation of the margins by 
 massage. The movement of the buccal attachments into the "anterior 
 position" has noticeably altered the form of the margin from the 
 median line to the bicuspids. 
 
 Figure 3 ID shows an impression like that in 33C except that 
 after carrying the buccal attachments into the "anterior position" the 
 patient relaxed all muscle tension. The buccal attachments then took 
 the "middle position" and the compound was adapted to them in this 
 position. Such adaptation seems to condense the buccal attachments 
 and in part, to destroy their definition, since they do not cut the im- 
 pression margin to anything like the depth shown in Figure 3lA, B or 
 C. This impression is practically perfect and cannot be dislodged by 
 any movements of the patient's lips and cheeks. After failures to obtain 
 satisfactory dentures at the hands of several dentists, the patient is 
 wearing, with great satisfaction, an upper denture made from a dupli- 
 cate of this impression. 
 
 50 
 
Fig. 31. 
 
 Four impressions of the same moi:th. A and B. The direction of the pull of the 
 buccal attachments is strongly backward, in these two impressions taken with the 
 mouth open. 
 
 C. The anterior attachment has muscle-trimmed the impression nearer the median 
 line and much less deeply. 
 
 D. The margin seems much less deeply trimmed, yet the impression is better 
 adapted. See opposite page. 
 
 %-- ^ 
 
 r r 
 
 A I'. C D 
 
 Fig. 32. 
 
 The same Impressions as In Fig. :!1 with a plaster inipressioii of the same mouth on 
 
 the left. 
 
 51 
 
THE AXTEEO-POSTEEIOR LEXGTH OF THE UPPEE 
 
 IMPEESSIOX. 
 
 The upper impression should he of the length desired in the 
 finished denture. This length will Ije determined by the condition 
 of the tissues. If the alveolar ridge in the front of the mouth is hard, 
 the denture should extend on to the soft tissues immediately posterior 
 to the hard palate. If the alveolar ridge in front is soft, the denture 
 will need to extend farther backward, on to the movable soft tissues, 
 in order that it mav be stable in biting. 
 
 The nausea which frequently results from dentures has l:)een gen- 
 erally thought to be caused ]jy the upper denture extending too far 
 backward, and efforts are made to relieve the condition by shortening 
 the denture. 
 
 Xausea is caused by imperfect adaptation of the posterior margin 
 of the denture. If the margin be adapted to lie in close contact with 
 the tissues when relaxed, the denture may be carried back as far as the 
 dentist desires, without causing nausea. But if the denture is made 
 over a model of the soft tissues in a distended position, the posterior 
 margin will not lie in close contact with those tissues when they are 
 relaxed. The soft tissues will then sustain an intermittent, vibrating 
 contact, which will tickle the nerve endino's and cause nausea. 
 
 If the tray be trimmed as suggested on page 18, and the posterior 
 margin adapted as suggested on page 54, nausea will not result, however 
 long may l)e the denture. I have seen many patients who had previously 
 been unable to wear dentures because of nausea, and for whom dentures 
 had repeatedly been shortened, who are wearing with complete satis- 
 faction very long dentures with the margins adapted to close contact 
 with the tissues when relaxed. 
 
 52 
 
I'i^'. ■■■.•■;. 
 
 Whistllii;? iiiovfuicnts to carry the l)ii'<-!il ;iUai'liiiiciits Into the aiitorior iiositioii. 
 
 5.^ 
 
ADAPTING THE UPPER IMPRESSION TO THE PALATAL 
 
 SOFT TISSUES. 
 
 Figs. Nos. 34: and 35. 
 
 It is important that the upper impression should be adapted to the 
 soft tissues which overlie the posterior part of the hard palate on either 
 side of the median line as shown in Fig, No. 35 A when these tissues are 
 relaxed. 
 
 Impressions taken with the mouth open, yield models of these 
 tissues in distended positions. When the mouth is closed, these tissues 
 occupy very different positions, and a denture made over a model 
 of their distended positions may fit them so poorly as to cause the 
 nausea described on page 52. If the denture fits these tissues in the 
 relaxed position, it will be stable at all times and will not cause nausea, 
 no matter how long it may be. 
 
 The impression is adapted to the relaxed position of these tissues 
 by adding compound from a stick over the entire area occupied by 
 these tissues, and while it is very soft, inserting the impression into the 
 mouth, the lower trial plate being in place, and having the patient close 
 the mouth and swallow two or three times. The tongue, is automatically 
 carried to the roof of the mouth during swallowing, and this action 
 drives the softened compound into firm contact with these tissues and 
 holds it there until it cools. It may be necessary to add compound in 
 this way two or three times before the added compound blends smoothly 
 with the rest of the palatal surface. Trim the impression to the exact 
 length desired in the finished plate. Then warm the posterior border 
 of the impression again and have the patient swallow a few times. 
 
 While the jaws are still closed together, the patient's lips are 
 parted, the upper trial plate is seized with the left thumb and forefinger 
 in the bicuspid regions, and held firmly against the vault, the patient is 
 caused to open the mouth and the right forefinger is passed across the 
 heel of the plate with gentle but firm pressure and the compound is 
 more firmly adapted against the vault and posterior to the tuberosities. 
 
 The finger pressure may carry the compound to a point which will 
 cause muscle strain. Have the patient immediately close the mouth 
 and swallow. If the compound be not too hard, this will equalize the 
 strain. If the compound hardens before these steps are completed, it 
 should be warmed and the process repeated. 
 
 The trial plate is now removed from the mouth and the buccal 
 margin of each side over the tuberosities should be warmed deeply, by 
 the aid of a small flame, without changing its form. The trial plate is 
 now quickly replaced in the mouth. The patient is caused to close the 
 jaws lightly in correct bite, and then to exert strong force in biting. 
 This pressure properly ^'muscle trims" the posterior parts of the buccal 
 margins to the movements of the muscles in this region. This trimming 
 is very important and often prevents mutilation of the tissues due to 
 congestion, or a tendency to force the plate forward in biting. 
 
 54 
 
Fig. 34. 
 
 A stick of compound is softened over the flames and compound from it is added to 
 the palatal surface of the impression over the area occupied by soft tissues in the mouth 
 being fitted. 
 
 i-'ig. :-.:>. 
 
 The areas within the white lines In "A" are the t hcr.rctical locations of tlie muscular 
 tlHHues overlying the hard palate. The area within the white line in "B" is that over 
 which compound waH added In adaptation of this denture to the relaxed position of these 
 muHcles. 
 
 55 
 
THE EFFECT OF ADAPTATIONS^ TO THE PALATE. 
 
 Figs. jSTos. 36, 37 and 38. 
 
 This Adaptation of the impression to the soft tissues mentioned 
 often effects an almost unbelievable change in form in this part of the 
 denture. An impression taken with the mouth open rounds downward 
 in this area, while one which has been adapted to the relaxed tissues. 
 either runs out nearly horizontal or actually turns upward. 
 
 Fig. ]Sro. 37 shows on the left an impression taken with the mouth 
 open and the tissues rounding downward in this region. 
 
 Fig. Xo. 37 shows on the right an impression of the same moutli 
 with the soft tissues compressed in their relaxed position. ]^ote that 
 the impression runs out horizontally. The diiference in thickness of 
 buccal margins and amount of compound may be disregarded. 
 
 Fig. ^o. 38 shows on the right a cross section of the impression on 
 the left in Figure 'No. 37. ]Srote the very decided rounding down of the 
 soft tissues in the posterior portion of the impression. 
 
 A denture made over a model from this impression will fit the 
 relaxed soft tissues so poorly as to probably cause nausea by vibrating 
 contact between denture and tissues. 
 
 Figure No. 38 shows on the left a cross section of the impression 
 shown on the right in Figure No. 37. oSTote the horizontal formation in 
 the posterior portion. This impression is much more stable in all posi- 
 tions of the mouth. A denture having this form could be extended as 
 far backward as the condition of the ridge in the anterior section re- 
 quired, without causing nausea. 
 
 Similar differences of form in other impressions can be seen by 
 referring to Figure Xo. 36. 
 
 This completes the work on the upper impression. It should now 
 be stable in all positions of the lips and cheeks, and should fit snugly 
 but not be uncomfortably tight. That impression is best which while 
 in position in the mouth, can be rotated slightly from side to side 
 without breaking suction. 
 
 56 
 
Fig. 3G. 
 
 A. Impression of open nnnith. Poorly adapted tray. Excess of compound. No 
 muscle-trimming. 
 
 B. Impression of same mouth, open. Margins built up but not trimmed thin. 
 Muscle-trimmed. 
 
 C. Impression of same mouth, muscle-trimmed and massaged with mouth closed. 
 Adapted to palatal soft tissues. White line outlines area over which compound was 
 added. 
 
 Fig. 37. 
 On the left, an impression df ;i iiicnith, open, with p;il;it;il si.rt tissues disteinhMl an 
 rounding down. On the rigid .-in iiiipi-cssion of tlie same iiKuiih \\iii<-li lias Ijeeii ad.ipti 
 to the i»alatal soft tissues in relaxed pusitidus. 
 
 Fig. .".8. 
 On tlie rigid, a cpohh Hpcfion of an inii)ressIon taken wltli tlie nioutli open. Note 
 Unw It r<>nn<lH down In tlie posterior part. On tiie left, an impression of the same 
 mouth properly adapted to the soft tissues overlying tlie hard palate. 
 
 57 
 
ESSEIsTTIALS OF COMFOET IN A LOWER DENTURE. 
 
 The acme of comfort in the average lower denture is secured only 
 when the denture is supported by pressure of its buccal and lingual 
 margins on the soft tissues at the base or sides of the ridge, rather than 
 on the top of the ridge. The margins of the denture must be adapted to 
 accommodate these tissues in their positions of extreme distention, and 
 sufficiently short so that the tissues will either not raise the denture or 
 if they raise it, will automatically re-seat it when the mouth closes. 
 
 An impression which will yield such a denture requires adaptation 
 by three distinct steps : 
 
 1. The outer rim must be "muscle trimmed" to the buccal and 
 labial tissues in positions of maximum distention. This can be done 
 only with the mouth open and conformed to the ridge with the mouth 
 closed. 
 
 2. The lingual rim, in the region of the bicuspids and molars, is 
 trimmed to the distended position of the sublingual tissues with the 
 mouth closed and the patient swallowing. The anterior portion of the 
 lingual rim is to be trimmed by the patient sticking out the tongue or 
 licking the upper lip. 
 
 3. After the margins have been trimmed as described under 
 ISTos. 1 and 2, the ridge surface in contact with extremely hard or very 
 soft tissue must be cut out considerably and then the entire ridge 
 portion of the impression is softened and the pressure at all points is 
 equalized under biting stress. This point is most important. 
 
 The experienced operator will be able to secure these adaptations 
 in not more than three operations, but whether three or ten are required, 
 they must be effected if the lower denture is to be comfortable and 
 efficient. 
 
 58 
 
FIXISHIXG THE LOWER IMPRESSION. 
 
 If the outer margin of the lower baseplate impression was cut 
 short, as directed on page 38, trace on additional compound from median 
 line to heel on one side, making it higher than the finished rim wdll be, 
 but not thick from ridge to cheek. Put the trial plate into the mouth, 
 have the patient open wdde, and by pressure on the bicuspid region of 
 each side, force it down to place. Then have the patient close the mouth 
 and perform the whistling and laughing movements. While the mouth 
 is closed and the cheeks are relaxed, make a quick, light massage over 
 the warm margin. 
 
 The movements of the cheeks will doubtless turn upward any excess 
 of compound that was built on. This should be trimmed away, and 
 the procedtire repeated until no more compound is turned upward. 
 
 When the margin is high enough on one side and is properly 
 trimmed, repeat the process on the other side of the outer margin. 
 
 If the lingual margin of the impression was cut short, trace on 
 compound in like manner, and at the same time warm the entire 
 balance of the lingual margin evenly and deeply, because the sublingual 
 are very weak but effective. Insert the trial plate into the mouth, the 
 upper being always in place, and have the patient close the mouth and 
 swallow. This will muscle trim the margins in the bicuspid and molar 
 region. Trim away excess and repeat till no more excess is turned up. 
 
 Warm the lingual margin of the anterior region, hold the trial 
 plate down on the ridge by pressure in the bicuspid regions, and have 
 the patient project the tongue or lick the upper lip. When the tongue 
 is withdrawn, pass the finger over the warmed margin and gently press 
 the compound against the ridge, without changing its form. 
 
 With a spoon instrument, deepen the impression of any prominent 
 hard spots or very soft or flabby places on the ridge. 
 
 The final step is perhaps most important of all. If the ridge sttr- 
 face of the impression is flat, immerse it in hot water to soften it without 
 changing its form and replace in the mouth and have the patient bite 
 very lightly in right relations, and whistle, laugh and swallow. 
 
 If the ridge is high, warm the impression surface in contact with 
 top of ridge with hot water from a syringe. This final softening and 
 biting permits all inuscl(! strain to be equalized and causes excess com- 
 pound to flow toward top of ridge. 
 
 59 
 
TAKIjNTG PAKTIAL IMPEESSIOiS^S. 
 
 (For the benefit of dentists who desire to take partial impressions 
 the following skeleton of ]\Ir. Supplee's method is appended. Such 
 impressions will be found valuable in making models for partial den- 
 tures and for extensive bridgework. 
 
 Lack of space forbids proper treatment of this subject. Those 
 desiring detailed information are respectfully referred to Mr. Supplee's 
 writings. ) 
 
 The buccal flange is trimmed away from the tray. The impression 
 material is prepared as described for full impressions and is shaped 
 to cover the surface of the hard palate, the lingual surfaces of the 
 remaining teeth and all surfaces of the ridge where teeth are missing. 
 
 Press the cup "home" and hold it until the compound has partly 
 set. Remove the tray and compound from the mouth in the direction 
 in which the finished denture is to be removed. Dip the surface 
 of the compound into cold water to slightly chill it ; then quickly insert 
 the tray again in the mouth and drive it "home" with pressure. 
 
 Cut the margins of comjDound about adjoining teeth to square 
 edges. Shape a roll of compound as for a lower impression and lay it 
 over the labial and buccal surfaces of the teeth. Pull the lip over it,. 
 press the compound in place, allow it to cool. 
 
 The above steps, if properly followed, obviate the taking of an 
 impression of the bell-shaped necks of teeth, which cannot be used in 
 the finished denture. They make it possible to produce a partial plate 
 which can be inserted into the mouth without trimming. 
 
 60 
 
Fig. 39. 
 
 < »n the left, a Siipiih'c iinper tray for jiartial innircssioiis. 
 
 (til tlie rigrbt. the iniiiressidii of the vault and the lingual surfaces of the teeth, with 
 the outside pieces laid back to show impressions of outer surfaces of teeth. 
 
 fiVKxaJv^sarviJWii.'aMiimzmmmiUMai-Wf-t-i.:. 
 
 Fig. 10. 
 
 • Ill (lie left, a Sii|iplec Iray for parliaj lovscr iinpicssions. 
 On tin- rlglit. a lower partial iin|iressloii v\ilh I he aulciior pii 
 linprefixloii (if labial siirface.x of antcrlors. 
 
 laid b.'udi to show 
 
 61 
 
poi:n'ts to be kemembered iit refitting upper 
 plates or in taking new impressions. 
 
 1. Always examine the mouth, first by feeling the tension of the 
 muscles with the mouth as nearly closed as possible, using the index 
 finger, and you will get an entirely different idea of the existing con- 
 ditions and the possible height of rim than by looking it over. 
 
 Put the finger in the mouth over the tuberosities and let the 
 patient close to find out the relation of the lower jaw to the upper. 
 Many plates are thrown by the passing of the two in mastication. Cut 
 off points of cusps which interfere with trituration. 
 
 2. Don't push plate all the way home. Let patient do that. 
 
 3. When patient can tip plate with tongue, it is too short in 
 the back, — or not imbedded deep enough into the soft tissues. 
 
 4. When plate drops in talking, the edge is not imbedded into 
 the soft tissues in the roof of the mouth and back of tuberosities. 
 
 5. When the plate drops from mastication, it either rocks on 
 the hard palate or is too low on the sides. Incidentally, see that there 
 are no prominent cusps catching on the opposite side from which it 
 drops first. 
 
 6. When the plate drops only when the mouth is opened wide, it 
 is generally too high in front. Shorten it or add material on the inner 
 edge ; it may also extend back too far on the dilating soft palate. 
 
 Y. If the patient gags, the plate is probably not long enough or 
 is not compressing the soft tissues, so as to eliminate the tickling 
 caused by the vibration of the soft tissues over the edge of the plate. 
 
 8. Build out plumpers, if required, in compound, when impres- 
 sion is being taken. 
 
 9. After plate has been worn, always cut out some of the old 
 material where you expect to add. 
 
 10. Don't build only on the edge of the rim, otherwise you will 
 get suction only by contact with the cheek, and the plate will soon get 
 loose or cut the cheek. Add the compound half between the rim and 
 the bottom of the ridge so as to compress the muscles at their base. 
 
 62 
 
Fig. 41. 
 Very firm r-losure of ttn" Jaws to trim the Impression margins to forward iiosition of 
 
 the massetcr muscles. 
 
 6.3 
 
PART II. 
 
 Selecting The Forms And Sizes 
 In Anterior Teeth 
 
FOEEWORD. 
 
 It gives me great pleasure to be able to introduce here tlie meth- 
 ods of tooth selection made possible bj the researches of Dr. J. Leon 
 Williams, and by the production of Trubyte Teeth in harmony with 
 his findings. These methods are so much more scientific and certain 
 than those in former use, and yield such superior results, that T am 
 sure they will replace all other methods as soon as perception of their 
 scientific worth and utility becomes common. 
 
 The dentist who must select teeth for a full upper denture, or 
 for an upper partial denture extending across the front of the mouth, 
 or for a bridge replacing the upper anterior teeth, must solve three 
 problems, which are: 
 
 To Select a Mould Harmonious with the Face. 
 
 To Select Teeth of the Proper Size. 
 
 To Select a Shade. 
 
 Wlion only a portion of the aiiterior teeth are to be selected, as in 
 the case of some partial dentures, short bridges, and porcelain crowns, 
 the dentist must select a mould of like character with the remaining 
 natural teeth, and of tlie sizes determined by the mechanical require- 
 ments. 
 
 I have briefly set forth Dr. Williams' findings regarding the selec- 
 tion of moulds in my own words in the following pages. 
 
 67 
 
THE ORIGIIsT OF FACE FORMS AND TOOTH FORMS. 
 
 In tlie days when the hnman face first assnmed its present pro- 
 portions, nature shaped three types of face, the square, the tapering, 
 and the ovoid (with the big end down) and made all other forms 
 by blending these. They were rough days and it took rough men to 
 survive, even to maturity. Tt is natural, therefore, that the types 
 should have been severe and strong, rather than what we should call 
 pleasing. 
 
 From those days to these, nature has formed all human faces in 
 these typal forms or by blending these forms, usually with one form 
 sufficiently prominent to give its character to the face as a whole. 
 Consequently, though we rarely have the severe types of faces now, 
 faces may be classified as modifications of the square, the tapering 
 or the ovoid. 
 
 In those early days when nature was forming types, she formed 
 also three types of teeth, and as she seeks always beauty and harmony, 
 the types of teeth were harmonious with the types of face, square, 
 tapering and ovoid. Since that time she has modelled all human teeth 
 upon these three forms. 
 
 The circumstances which have modified the forms of faces, seem 
 to have modified the forms of teeth in like manner, so that all teeth 
 which are not of the severe typal forms may be classified as modifica- 
 tions of the square, the tapering or the ovoid. 
 
 Dr Williams has conducted extensive studies of face-forms and 
 tooth-forms, in those museums which contain the finest collections of 
 human skulls. He has demonstrated that in every race from which we 
 have any consideral)le collection of skulls, nature has produced the 
 same typal forms of teeth and made all other forms by blending these. 
 These races are ancient and modern, savage and civilized, and from 
 every quarter of the earth. 
 
kkkkikklkA 
 
 I'iir. 41. 'I'yiial Idriiis in ii])ii('r centrals, ("lass I at top. 
 
 
 I'ijr. 4"J. Tyjial tUniis in upper latprnls. Class I at top. 
 
 II llllllfi 
 
 kkkkiinui 
 
 kkilkkUikk 
 
 I-'iK. 1.'!. 'I'ypiil fnrtiis in upper inspids. Class I .'it top 
 
HARMONY BETWEEN FACIAL FORMS AND TOOTH 
 
 FORMS. 
 
 In the davs before modifications of facial forms and tooth forms 
 became the rule, it is possible that nature always placed square teeth 
 in square faces, tapering teeth in tapering faces and ovoid teeth in ovoid 
 faces. If so, she secured harmony, even if the forms were too severe 
 for our notions of beauty. 
 
 As modifications of typal forms in faces and teeth multiplied, 
 nature seems to have lost control of the situation, and to have fre- 
 quently allowed like modifications' to become separated, so that there 
 is no longer any necessary relation between the type of the face and 
 the form of the teeth. While there are luany examples of harmony, 
 there seem to be even more examples of disharmony. Square teeth are 
 now often found in ovoid faces and ovoid teeth in square faces. The 
 extent of the disharmony and of its effect is determined by the character 
 of the modifications in face and teeth. If both modifications tend toward 
 a common type, the efi'ect may not be unpleasant. But if they tend 
 toward different tjq^es, the result may not be pleasing. 
 
 This knowledge of typal forms in faces and teeth, of their modi- 
 fications, and of the laws of harmony between them, liberates the den- 
 tist who is to select all the anterior teeth, from any servitude to the 
 form of teeth which the patient may have exhibited. His guidance is 
 to be found in the type of face, and his task is to select teeth to har- 
 monize with the face rather than with any teeth which have gone 
 before. 
 
 When some natural anterior teeth remain, as in many crown and 
 bridge cases, the dentist will disregard the type of face and select a 
 mould to harmonize with the natural teeth. 
 
 Dr.' Williams' methods make such selection very easy and rapid, 
 but before taking them up it may be well to devote a few words to a 
 description of the methods of selection which have been in force up to 
 this time, but which I believe will speedily become obsolete. 
 
 70 
 
fi ^ -^^^ a 
 
 » - 
 
 
 If*^ 
 
 
 
 ^^^^^^^^k. . ^^^^^Wj^M^'- ,^^^^^^^1 
 
 
 Fig. 44. Sandwich Islanders, showing Classes I, II and III, In natural teeth. 
 
 Fig. 45. Chinese Skulls, showing Classes I, II and III, in teeth. 
 
 Fig. 4C. Tu.Huianlaus, showing Classes I, II and III, In teeth. 
 
 71 
 
THE TEMPERAMENTAL THEORY OF TOOTH FORMS. 
 
 The theory which has most commonly served as a basis for the 
 selection of teeth assumes that people can be divided into four groups, 
 according to the color of the hair, skin, and eyes, and the physical char- 
 acteristics of size and form. It assumes also that the people of each 
 group exhibit a characteristic form of tooth, so that we have a bilious 
 form, a sanguine form, a nervous form, and a lymphatic form. The 
 temperaments were supposed to be blended together in different propor- 
 tions and the tooth forms to be similarly blended. 
 
 I have studied this theory of temperaments, but the more I studied 
 the less I knew. I believe this to be the usual experience, and I doubt 
 if it is taken seriously by many dentists. It has long since been aban- 
 doned in all the other great departments of medicine. 
 
 The temperamental theory assumes also that there is in each 
 human body a governing principle which insures harmony of form and 
 size among its several parts, so that all teeth are harmonious in size 
 and form with the contour of the skull and face. If this part of the 
 theory were true, we should all be examples of symmetry if not of 
 beauty, instead of exhibiting the rather heterogeneous collection of eyes, 
 ears, noses, mouths and teeth which are so common to-day. 
 
 Dr. Williams' studies have clearly established that there are no 
 temperamental forms of teeth by showing : 
 
 1st. That people of every variation of stature and color had iden- 
 tical tooth forms. 
 
 2nd. That people of like stature, contour and color had very un- 
 like forms of teeth. 
 
 The following illustrations so establish these points that we may 
 dismiss forever from our minds the notion of temperamental or racial 
 forms of teeth. 
 
 Certain leading manufacturers claim to have produced porcelain 
 teeth in moulds characteristic of the four great temperaments. Un- 
 fortunately they have differed so radically among themselves as to have 
 produced entirely unlike moulds for the same temperaments. 
 
 It is very doubtful whether the manufacturers ever took the temper- 
 amental theory any more seriously than as a means of satisfying certain 
 dentists, obtaining unpaid-for advertising, and securing additional tooth 
 orders. Certain it is that most of the moulds of porcelain teeth have 
 been carved by copying natural teeth, and that largely without relation 
 to the dentist's needs. There has been no system of graded sizes, so 
 that a mould could be had a little lar2.er or a little smaller than a given 
 size. And many of our finest efforts have been thwarted because suit- 
 able teeth could not be had. I believe Dr. Williams is right when he 
 says that prosthetic dentistry has sunk to its present neglected condi- 
 tion because we have not had proper teeth to work with. 
 
 72 
 
Fig. 4". Ancient Egyptian Skulls, illustrating the three typal furms of teeth. 
 
 Fig. 48. Skulls of modern Hindoos- excellent specimens of Classes I, II and III. 
 
THE APPLICATION^ OF THESE DISCOVERIES TO 
 PORCELAIN" TEETH. 
 
 The discovery of the typal forms of natural teeth and their modi- 
 fications, wonld be of little value to ns or our patients if no porcelain 
 teeth like them could be had. Dr. Williams knew this. He had labored 
 for this discovery with the intention of producing porcelain teeth, 
 which should be harmonious with all forms of faces and natural teeth. 
 Porcelain anterior teeth shaped in accordance with his discoveries and 
 bicuspids and molars shaped in accordance with Prof. Dr. Gysi's dis- 
 coveries, have been produced under the distinctive name teubyte 
 
 TEETH. 
 
 Dr. Williams calls the Square Type ''Class I", the Tapering Tvpe 
 "Class II", and the Ovoid Type ''Class III". 
 
 Dr. Williams has isolated five modifications of tooth forms in 
 Class I ; four in Class II, and four in Class III. 
 
 These modifications have not been made by copying natural teeth. 
 That method has proven a failure in the hands of every one who has 
 given it serious trial. They have been made by studying nature's work, 
 until her object and her methods were known. The defects which ap- 
 pear in nearly all sets of natural teeth were eliminated, and the funda- 
 mental principles of beauty in tooth form were discovered and utilized. 
 The laws of harmony, as exhibited in nature's finest achievements, were 
 applied to the accomplishment of nature's object, this time in porcelain. 
 
 A number of practical advantages to us as prosthetic workers re- 
 sult from this method. They may be briefly summarized as follows : 
 
 We are taught how to classify faces for selection of teeth for full 
 dentures, and how to classify natural teeth so that we may know what 
 type of artificial teeth we should select in partial cases. 
 
 We may use the drawings of facial outlines in this book and quickly 
 determine the type and modification of face, or the drawings of teeth 
 and determine the type and modification of natural teeth. 
 
 The endless and seemingly planless collection of artificial teeth 
 from which we have selected in the past gives way to a comparatively 
 few moulds, so arranged as to have greater matching power than all the 
 moulds of the past. 
 
 The availal;)ility of the comparatively few moulds is much greater 
 than their number would indicate. A given face may lie on the border 
 line between types, that is, be a blending modification of, say Class I and 
 Class II. It may be that two moulds in either class would be suitable. 
 We are thus furnished four moulds in, say four sizes each, suitable for 
 that face, a thing unknown before. 
 
 Each mould is produced in several sizes. These sizes vary about 
 one millimeter in the length of the labial surface of the upper central, 
 exclusive of collar. 
 
 The illustration of each mould and the dimensions of its several 
 sizes are tabulated to make them immediately available. 
 
 Identical moulds will be available in vulcanite teeth, in porcelain 
 crowns, and in facings for bridge work. 
 
 74 
 
Fig. 50. 
 
 Nine skulls ot different ra'-es and unlike size and eontour, all with teeth of Class I. 
 Tlie form and size of the teeth bear no relation to the form or size of the skull. 
 
 NatlonalltleH from left to right are: 
 
 .Spanisli, Sandwleh Islander, New Hebrldean, German, .Tavanese, Ilindno, I'Mjl Islander, 
 Italian, Ancient Egyptian. 
 
 75 
 
DETEEMII^TI^^G THE TYPE OF FACE AND OF TEETH. 
 
 If one lias illustrations of. the chief modifications of the three 
 typal forms of faces, it is easy to determine the dominant type in the 
 face, and the character of the modification. One has only to compare 
 illnstrations with the face, till the illnstration most like the face is found. 
 Such illustrations will be found on pages 79, 81 and 83. 
 
 Below the illustration of each facial modification will be found a 
 notation as to which Trubyte mould is suitable for faces of that particu- 
 lar form. The size of the teeth will be determined by mechanical con- 
 ditions which will be described later. 
 
 Because this method of selection is so easy and rapid, it must not 
 be thought that it is unscientific. It is in the highest degree scientific 
 and artistic, and is only made easy because the preliminary work has 
 been completed by Dr. Williams. 
 
 When remaining natural teeth are to be matched, the outline illus- 
 trations of tooth forms on pages 85, 87 and 89 should be used to select 
 the most suitable mould of porcelain teeth. The size will be determined 
 by the mechanical conditions. 
 
 An illustration exactly like every face is not necessary to success- 
 fully determine the type and modification. There are nearly as many 
 minute modifications as there are faces, since a feature or a line here 
 and there will differ from that found in any other face. But the pro- 
 portions of length and width are relatively constant in the several chief 
 modifications. And the lines which bound the outline of the face, 
 when seen full front, will have one of three general directions, parallel, 
 converging downward or diverging downward. They are of three gen- 
 eral characters, straight lines, flat curves, full curves. It is really sur- 
 prising how rapidly and how accurately the faces which present may 
 be classified, and hov\^ close many of them are to the standard modifica- 
 tions. 
 
 76 
 
I'ijr. .',1. 
 
 lOiKlit sknllis of unlike si/,.' :iiiil loiin. All cxhil.it l<'clli ..1' Class 111. The r.iriii mid 
 mI/,c <>r llic teeth ))e;ir no rehitir.ii to llie roim or si/.c> of the sUiill. 
 
 Nittloiialities from l<'ft to riKlit : An AiistiMlian. Sandwich Islander. Ancient Efiyptiali, 
 Kiillir. riiinese, African Savaj."-. N<'" llchridcan. llimloo. 
 
 11 
 
MODIFICATIONS OF THE SQUAKE TYPE OF FACE. 
 
 Faces exliibiting modifications of the square type are more mimer- 
 ous than any others- — perhaps as many in number as all the other types 
 combined. 
 
 Most faces of this type exhibit nearly parallel sides, bounded by 
 straight lines or flat curves, with short curves at the angles of the 
 jaw, and rather wide chins. 
 
 Five modifications of this type are worthy of careful attention. 
 Teeth harmonious with these five will be found harmonious with prac- 
 tically all faces of the square type. 
 
 The first modification is one in which the length of the face is 
 much greater than its width. 
 
 The second modification is one in which the length of the face is 
 but little greater than its width. 
 
 The third modification is one in which the length and width of the 
 face are about equal. 
 
 The fourth modification is one in which the outline has been a trifle 
 softened by slightly lengthening the curves at the neck. It is usually 
 found only in female faces, and may be called a feminine modification. 
 
 The fifth modification is one in which the curves at the angles of the 
 face have been noticeably lengthened, and the approximal curves some- 
 what rounded. This constitutes the oval face. 
 
 Outlines illustrating these facial modifications are shown on the 
 opposite page. Below each has been placed a notation as to the mould 
 of Trubyte teeth harmonious with that particular form of face. 
 
 78 
 
Square face— long. 
 Class I. Mould 1. 
 
 Square face— long. 
 Class I, Mould 1. 
 
 Square face -medium. 
 Class I, Mould 2. 
 
 Square face— medium. 
 Class I, Mould 2. 
 
 Oval. 
 
 Oval. 
 
 79 
 
MODIFICATION'S OF THE TAPERi:^rG TYPE OF FACE. 
 
 Faces of this type are wider above the eyes than below, and taper to 
 the chin by straight lines or flat curves. The chins are wider in some 
 faces than in others, but they are not the wide, square chins of the 
 square type of face. 
 
 The severe typal form of this face expresses great force and en- 
 durance. It is most likely to be found among people who have lived 
 physically strenuous lives, generally outside the softening influence of 
 luxury. It is not pleasing in modern eyes. 
 
 The crossing of races and the influences of civilization have pro- 
 duced modifications of this type by blending with the square or ovoid 
 types, and many of these faces are pleasing in appearance. Such faces 
 are perhaps most often found before the period of life when the body 
 takes on excess tissue and its outlines change. 
 
 Faces of the tapering type do not exhibit the same character of vari- 
 ation between length and width that square faces do. There are, of 
 course, all proportions of lengths and widths, but when faces of differ- 
 ent proportions are compared, they are generally seen to be different 
 modifications of the typal form, rather than similar modifications with 
 different proportions. 
 
 It is believed that the illustrations on the opposite page are suffi- 
 cient to enable the dentist to classify practically all the facial modifica- 
 tions of this type which appear. 
 
 80 
 
Tapering face — long. 
 Class 11, Moulds. 
 
 Tapering face — long. 
 Class II, Moulds. 
 
 'J'apr-ring faf-e. 
 Class 11, .Moulds. 
 
 Tapering face. 
 Class II, .Moulds. 
 
 81 
 
MODIFICATIOISrS OF THE OVOID TYPE OF FACE. 
 
 The ovoid type of face is distinguislied by being wider below the 
 eyes than above them. Faces of this type are nearly always bounded 
 by lines exhibiting compound curves. They frequently exhibit wide 
 chins, but the differences in the contour of the sides of the face save 
 faces of this type from confusion with faces of the square type. 
 
 Ovoid faces do not exhibit the same kind of variation between 
 length and width that is found in the square type. They are, of course, 
 of all sizes and of many proportions, but it will usually be found that 
 faces of this type which differ markedly in proportion of length to 
 width are different modifications of the typal form, rather than the same 
 modifications with different proportions. 
 
 Faces of this type are more common among people of mature age 
 than among young people. Very often people take on flesh with the 
 passing of the years, and the whole body changes in outline. The face 
 fills out in the lower part and adipose tissue may make this part wider 
 than the face above the eyes. People who live in luxury and without 
 much bodily exercise, are more apt to exhibit this type of face than 
 those of abstemious lives and active physical habits. 
 
 The border line of demarcation between some faces of this type 
 and some of the square type is often very delicate and there are 
 faces for which a modification of either type may be suitable. 
 
 The illustration of the faces on the opposite page will assist in 
 classifying faces of this type. 
 
 82 
 
Ovoid face 
 Class III, Forms 
 
 Ovoid face 
 Class III, Forms 
 
 Ovoid face 
 Class III, Forms 
 
 Ovoid face 
 Class HI, Forms 
 
 83 
 
MODIFICATIONS OF THE SQUAKE TYPE 11^ TEETH- 
 CLASS L 
 
 ISTatural teeth of this type are more common than any others. The 
 upper centrals exhibit parallel or nearly parallel approximal sides for 
 1/3 or 1/2 of the length of the crown upward from the incisal edge. 
 The upper laterals and cuspids exhibit similar formation, though not 
 always to the same degree. 
 
 The necks of the teeth are wider than in either of the other types 
 and join the approximal surfaces by rather short curves. All the an- 
 teriors have the appearance described by the word "square." 
 
 The teeth of this class exhibit three relations of length to width. In 
 one, the length is much greater than the width. In another the length 
 is but little greater than the width. In the third, the length and width 
 are about equal. jSTo other type of teeth exliibits this peculiar variation 
 of length to width. These modifications are exhibited in Forms 1, 2 
 and 3, Class I. 
 
 A very pleasing modification of this type is found almost exclus- 
 ively in female faces. It is usually small in size, and the square appear- 
 ance has been somewhat softened by lengthening the curves a little. 
 This modification is exhibited in Form 4, Class I. 
 
 The oval tooth is a modification of the square type and is made by 
 lengthening the curves of the neck and approximal sides. This modi- 
 fication is exhibited in Form 5, Class I. 
 
 Square faces and square teeth are more common than any others, 
 and the five modifications here shown will meet the requirements of a 
 great number of cases. 
 
 A detailed description of each of these forms appears in connec- 
 tion with the illustrations and table of sizes in the l)ack of the book. 
 
 84 
 
CLASS I MOULDS 
 
 Form 1. The long square form. 
 The sizes are marked as Moulds IC, ID, IE. IF, IH. 
 
 Form 2. The medium long square form. 
 The sizes are marked as Moulds 2C, 2D, 2E, 2F, 211. 
 
 Form :i. The short square form. 
 The sizes are marked as Moulds 3C, 3D, 3E, 3F, 3H. 
 
 Form 4. A delicate feminine modifloation of Munhl 
 The sizes are marked as Moulds 4D, 4E. 
 
 Form .">. 'I'hc ov;il furin. 
 The sizes are marked !is Moulds 5(', ijl>, ijE, 5F 
 
 85 
 
MODIFICATIONS OF THE TAPEEIN^G TYPE OF TEETH- 
 CLASS II. 
 
 Teeth of the severe typal form are distinguished by nearly 
 straight approximal surfaces which converge so rapidly in some cases 
 that they would meet at the middle of the root, and in other cases at 
 the end of the root. These severe forms are rarely pleasing and there is 
 no necessity for their reproduction in porcelain, since the modifications 
 exhibit all the typal characteristics in more pleasing form. 
 
 Teeth of this type do not exhibit the same kind of variations of 
 length to width that are seen in Class I. Teeth of this type exhibiting 
 widely varying relations between length and width will usually be 
 found to be different modifications. 
 
 Form 1 in this class is the severe typal form modified just enough 
 to rob it of the severity and exhibit the beauty of the type. It is a very 
 striking mould and has commended itself to the artistic sense of dis- 
 criminating workers. 
 
 Form 2 differs from Form 1 in that the severity of the typal 
 form is slightly more softened. This is suitable for faces in which the 
 cheek lines are a little fuller and not quite so straight. 
 
 Form 3 exhibits fuller curves on the distal surfaces of the upper 
 anteriors and is suitable for faces in which the cheek lines are filled out 
 enough to present slightly convex curves. 
 
 Form 4 is probably the softest modification of this type which will 
 be required. It will be found useful for faces and teeth which are just 
 this side the border line between this type and the ovoid. 
 
 Each of these moulds is offered in a series of convenient sizes. 
 
 When Dr. Williams first brought this type of tooth to my atten- 
 tion, it appeared to me as the least beautiful of the typal forms, and I 
 thought it would find less use in prosthesis than either of the others. 
 I know now that I felt that way because I had never properly observed 
 it in natural teeth. Since I have learned to look for it in natural 
 teeth, I find it common in what I might perhaps call the typical Ameri- 
 can face, that is, the clean cut face with straight cheeks and no superflu- 
 ous tissue. I find also that in such faces this form of tooth is very 
 pleasing and it now seems to me quite as fine as either of the other two. 
 
 I have seen these teeth in prosthetic cases, and the effects are very 
 pleasing. There is an appearance of clean cut vigor about them which 
 neither of the other types exhibits, and dentists who wish to break 
 away from the usual forms of teeth will find the modifications of this 
 type very useful. 
 
 A detailed description of each of these forms appears in connec- 
 tion with the illustrations and table of sizes in the back of the book. 
 
CLASS II MOULDS 
 
 Form 1. 
 
 A severe, nearly typal form. 
 
 The sizes are marked as Moulds IL, IM, IN, IP, IR. 
 
 Form 2. 
 
 The severity of Mould 1 is here noticeably softened. 
 
 The sizes form Moulds 2L, 2M, 2N, 2P, 2R. 
 
 Form 3. 
 
 A still softer modification. 
 
 The sizes form Moulds 3L, 3M, 3N, 3P, 3R. 
 
 Form 1. 
 The softest modification. 
 The sizes form Moulds 4L, 4.VI, 4N, 4P, 4R. 
 
 87 
 
MODIFICATIONS IK THE OVOID TYPE OF TEETH- 
 CLASS III. 
 
 The severe typal form of these teeth is, as the word ovoid shows, 
 distinctly egg-shaped, the big end of the egg being downward. It is 
 distinguished by a strong convex curve on the mesial approximal sur- 
 face and a well marked double curve high on the distal surface. The 
 severe typal form would be harmonious only with faces of very strongly 
 marked character and would not be beautiful then. 
 
 The modifications of this type are, however, by far the most 
 graceful, and in some ways the most beautiful of natural teeth. They 
 exhibit a delicacy and beauty of contour which neither of the other 
 types can show, and in faces for which they are suitable cannot but 
 achieve the finest of results. 
 
 The modifications of this type do not show the same form of vari- 
 ation in length and width as did the square type. Different modifica- 
 tions may be of different length for a given width, but in any given 
 modification the proportions of length and width are relatively con- 
 stant. 
 
 Form 1 is the nearest to the typal form that a modification can 
 be and exhibits the beautiful curves which are characteristic of this. 
 type. 
 
 Form 2 is a slightly softer modification and is suitable for faces, 
 not quite as strong in type as those requiring Mould 1. 
 
 Forms 3 and 4 of this type are still softer modifications. 
 
 Each of these forms is offered in a series of convenient sizes. 
 
 A detailed description of each of these forms appears in connection 
 with the illustrations and the table of sizes, in the back of the book. 
 
CLASS III MOULDS 
 
 Form 1. 
 
 A nearly tyiial form of imich strength, suitable for mascnllne faces. 
 The sizes are marked as Moulds lU, IW, IX. lY, IZ. 
 
 Form 2. The typal form is here modified and softened. 
 
 feminine faces. 
 The sizes are marked as Moulds 2T 
 
 This form is suitable for 
 2W. 2X, 2Y, 2Z. 
 
 Form 
 
 . The typal form is here more moditied than in forms 1 and 2. 
 The sizes are marked as Moulds 3U, 3W, 3X, 3Y, 3Z. 
 
 Form 4. The tyjial form Is here e.vtenslvely niodilled. 
 The BlzeH are marked as .Moulds 41', 4W, 4X, 4Y, 4Z. 
 
 89 
 
SELECTI]^G ANTEKIOK TEETH OF PKOPER SIZES. 
 
 Two methods of selecting artificial teeth were in vogue in my 
 early days in practice. One was for the dentist to go to the depot and 
 there select from among the hundreds of moulds the one he thought 
 most suitable. The other was for the dentist to send a model and let 
 a clerk who had never seen the patient, make the selection. Both were 
 wasteful of time and often unsatisfactory in result. 
 
 It seemed to me that if I could learn in advance just what mould 
 of teeth was required by a case, selection could be greatly facilitated. 
 By measuring with a millimeter gauge the distance between the marks 
 which I had been taught to make on the trial plates for the high lip 
 line and the low lip line, and adding one or two other marks, it became 
 very easy to tell just how long a central was needed, how wide a set 
 of anteriors, and how wide a full set of fourteen. 
 
 When this method was published under the title of The Twentieth 
 Century Method of Selecting teeth, accompanied by tables of tooth di- 
 mensions in millimeters, it was necessary only to scan the tables until 
 the mould most nearly like the requirements was found. The order 
 could then be sent by mould number. It was quicker, easier, and more 
 satisfactory than the old method. 
 
 Experience has shown no reason for changing this method for se- 
 lecting sizes. It has found its way into all corners of the world, has 
 become standard practice in many offices and is taught in several col- 
 leges. It has placed selection in the hands of the dentist, who is most 
 competent to select well ; has made it evident that teeth for full dentures 
 must be selected from the trial plates and not from the model; has 
 shortened the time required for selecting moulds, has insured the re- 
 ceipt by the dentist of just the teeth he had in mind for the case; and 
 has resulted in the selection of more satisfactory teeth in most cases. 
 
 The length of upper central should be marked first, then the length 
 of the lower central, then the width of the six upper anteriors. The 
 width of the upper central is determined by the form which was se- 
 lected by means of Dr. Williams' drawings. 
 
 The patient is asked to raise the upper lip in smiling, and the lo- 
 cation of its edge is marked on the trial plate. If the necks of the upper 
 centrals are located on this line, the gums will not be exposed in smiling. 
 
 The chances are better than 3 in 5 that this is the right location for 
 the necks of the upper centrals, because out of some thousands of people 
 whom I counted smiling, 3 in every 5 raised the lip to the level of 
 the necks of the upper central. Even if this would make the teeth 
 a little long, it is more artistic to have them so than to expose pink 
 rubber in smiling and a greater expanse of it in laughing. 
 
 If the lower lip is depressed by the action of the depressor muscles 
 and the location of its edge is marked in the same way, it will indicate 
 the point to which the lower centrals must extend to prevent exposure 
 of the lower gum in smiling. 
 
 If the orifice of the mouth is well proportioned to the face, the 
 distal angles of the upper cuspids may with advantage come close to 
 the angles of the orifice. To locate these angles, an instrument is in- 
 
 90 
 
Fig. 52. 
 
 The upjier li|» was raised by ttio elevator muscles and Is held by the tiiiger merely for 
 
 purposes of Illustration. 
 
 91 
 
SELECTING ANTEKIOK TEETH OF PROPEK SIZES— 
 
 Continued. 
 
 troduced between the lips, in the median line, and moved to one angle 
 and then the other and a mark on the trial plate at the location of each, 
 after the manner shown in Figure JSTo. 53. If the orifice is nndnly 
 large or small for the other features, the distance between the marks 
 may be shortened or lengthened. But it should be remembered that the 
 teeth are closer to the orifice than to the other features, and that it is 
 better, on the whole, for them to be a little large or small for the other 
 features than noticeably large or small for the orifice. 
 
 One other dimension in anterior teeth is important at least in cases 
 where the absorption of gum tissue is so slight as to leave little room 
 between the upper and lower ridges. It is the dimension of that part 
 of the teeth intended to sit below the level of the upper ridge, or above 
 the level of the lower ridge. It is the dimension of the greatest com- 
 bined bite and shut available in the case. A short study of an artificial 
 anterior tooth will make plain the meaning and importance of this 
 dimension. 
 
 Figure 'No. 54 represents a vertical section through an upper an- 
 terior tooth. It will be seen that the lingual surface has three divisions, 
 the bite, the shut, and the ridge-lap. Of these, the shut and ridge-lap 
 are intended to sit below the level of the ridge in those cases where the 
 denture must be so thin in front that the teeth be close to the ridge. In 
 cases where the absorption of the anterior plate of the upper alveolus 
 is complete, the teeth will usually be placed a little way in advance of 
 the ridge, and the length of the combined bite and shut is therefore 
 not so important. But in those close bite cases, where little room is 
 available at best, attention to this detail will enable the dentist to select 
 teeth of a size which will not need to be ground. 
 
 Before I adopted Mr. Supplee's method of making the impression 
 into a trial plate, it was easy to thrust a pin through the wax of the 
 trial plate on a level with the surface of the ridge. But the presence 
 of the impression tray in the trial plate renders this method imprac- 
 ticable. It is, however, easy to measure, on the palatal side of the im- 
 pression, the distance from the top of the rim to the deepest part of 
 the impression, and transfer this measurement to the labial surface of 
 the trial plate, where it answers every purpose accomplished by the 
 pin hole. 
 
 The area to be filled with anterior teeth is now well defined on 
 the trial plates, and it is necessary only to determine the distances in 
 millimeters, and to have at hand the dimensions of the required teeth. 
 The distance from the high line to the incisal edge of the trial plate is 
 the length of the labial surface of the upper central incisor. The dis- 
 tance from the low line to a point a millimeter above the incisal edge 
 of the lower trial plate is the length of the labial surface of the lower 
 central incisor. The distance from the mark at one corner of the ori- 
 fice around the trial plate to the other similar mark, is the width of 
 the upper anteriors, when set up. If the bite is close, the distance from 
 
 92 
 
l-i;r. .'..;. 
 
 It is hi-tUT to iiisf-rt the iMstniipicnt in the iri<Mli;iii line ;iiiil move it to the ailKlcs. The 
 pjitlcnt is less likely to ilniw tlic Ii|i t);i<-li ami uivc a false location. 
 
 93 
 
SELECTII^G A^TTERIOK TEETH OF PROPER SIZES 
 
 — Continued. 
 
 the surface of the upper ridge to the incisal edge of the trial plate is 
 the required combined bite and shut of the upper central. 
 
 If now, reference is had to table in which the dimensions of the 
 several sizes of the required type of tooth are listed in millimeters, the 
 size most suitable can readily be selected. It can then be ordered by 
 mould number. 
 
 Millimeter measurements of Dentsply, Solila, Twentieth Cen- 
 tury and Trubyte teeth are given as tables in the back of this book. 
 With all the variations possible to the human mouth, one must not 
 expect to always find a mould exactly right in every particular. But 
 with surprising frequency a mould will be found which will closely 
 approximate the required dimensions. And selection by this method is 
 likely to be more satisfactory than by the haphazard methods of the 
 past. 
 
 Dr. Williams' classification of faces and teeth and standardization 
 of sizes greatly facilitate satisfactory selection. Many faces exhibit 
 modifications which lie between two types of teeth, as between the 
 square and ovoid types. For such faces a modification of the square 
 type and a modification of the ovoid type may be equally suitable. If, 
 in such a case, the required dimensions cannot be found in the mould 
 of the square class, it is possible that they may be obtained in an 
 equally suitable mould in the ovoid class. 
 
 DETERMINING THE WIDTH OF THE FULL SET. 
 
 When the trial plates have been taken from the mouth, it can be 
 determined how far back on each side the teeth should extend. A mark 
 can then be made to locate the distal side of each second molar. This 
 location cannot be made in the mouth, or from any measurements taken 
 in the mouth, but is determined wholly by the dentist's judgment. 
 
 By measuring around the trial plate from one of the marks to the 
 other, the width of the full fourteen, in millimeters, is determined. 
 This measurement affords an example of the importance of selecting 
 teeth from the trial plate rather than from the model. The width of 
 the full set, when in place on the model, is from 2 to 4 or 5 millimeters 
 greater than the width of the set when flat on the wax. It is important 
 therefore that sizes should be selected from tables having the dimensions 
 of the anteriors and full sets when set up. 
 
 It is not uncommon for a mouth to be so ill-proportioned as to 
 require wide anteriors and narrow posteriors. If full sets do not come 
 carded to meet such requirements, the dentist may make up his own 
 sets ordering anteriors and posteriors separately. 
 
 Trubyte posteriors are made in four mesio-distal widths, 28 m.m., 
 30 m.m., 32 m.m., and 34 m.m. The dentist may order any of these 
 for use with any anteriors, but if disproportionate sizes are ordered, it 
 will be necessary to grind for adjustment where the posteriors and an- 
 teriors join. 
 
 94 
 
COLLAR-/ 
 
 COMBINED 
 
 BITE 
 
 AND 
 
 SHUT 
 
 -., RIDGE 
 7 LAP 
 
 SHUT<, 
 
 BITE 
 
 Fig 54. 
 Section through an upper central showing the divisions of the lingual surface 
 
 Fig. 55. 
 Trial plates markcrl for measuring. 
 
 95 
 
Fig. 56. 
 
 Fig. 57. 
 Measuring bite horizontally to get combined width of six anteriors and full set of 14. 
 
 96 
 
selecti:n^g teeth for partial cases, bridges and 
 
 CROWXS. 
 
 The most satisfactorv and economical method of selecting any form 
 of teeth for cases where less than the fnll denture is to be restored is 
 to have at hand a Mould Guide of the make of the teeth to be used, and 
 to fit sample teeth from that guide onto the case. By this means, both 
 dentist and patient can see just what the effect is to be. The order 
 for the teeth can be made out by mould and shade number, and the 
 results will be as desired. Or regular stock teeth can be kept on hand 
 and tried in this way. 
 
 This method is far more available with Trubyte teeth than with 
 any others, because identical moulds of vulcanite teeth, platinum pin 
 facings and porcelain crowns will be produced. It therefore requires 
 the dentist to keep fewer teeth on hand. For the selection of a porcelain 
 crown, the vulcanite teeth may be tried in place. The labial surface of 
 the porcelain crown will be like that of the vulcanite tooth, and the 
 mould will have the same number in crowns. 
 
 Dentists who do not wish to purchase a Mould Guide or stock teeth 
 to use as such, may apply the Twentieth Century Method of Selecting 
 Teeth, and procure the dimensions of the required teeth in millimeters, 
 by using calipers to measure the space for a single tooth, or by making 
 a partial trial plate and measuring around the curves. Selections can 
 be made from the tables in the back of this book. 
 
 SELECTING LOWER TEETH. 
 
 When full upper and lower sets are selected at one time, no meas- 
 urements for the lowers need be taken. If upper teeth are not being 
 selected, the sizes of the required lowers should be marked on the lower 
 trial plate, the dimensions o])tained in millimeters, and selections made 
 from the tables in this book. 
 
 For full dentures, the bicuspids and molars should be of the com- 
 bined mesio-distal width necessary to extend the full set back to the 
 locations marked for the distal sides of the second molars. 
 
 For full cases Trubyte Molar Blocks will be found superior to 
 plain teeth. They are made in the same moulds and shades as the plain 
 vulcanite teeth. They are described in connection with Trubyte bicus- 
 pids and molars. 
 
 For partial cases, the plain teetli or Molar Blocks should be selected 
 from a Trubyte Mould Guide. Much better selection results from try- 
 ing in the sample tootli thnii is y)ossible by any system of measurement. 
 
 97 
 
PART III. 
 
 Colors In Natural And Artificial 
 
 Teeth 
 
FOEEWOED. 
 
 Color plays as important a part in determining the beauty of arti- 
 ficial teeth and their suitability for any given case as does form or size. 
 If the color and shade selected are harmonious with that of the general 
 complexion in edentulous cases, or the other teeth in partial cases, 
 minor discrepancies in form or size are seen only on close examina- 
 tion. But if the color or shade is noticeably wrong, the falseness of 
 the restoration is at once detected. And no perfection of form or size 
 can make up for the visible defect in color. 
 
 When Dr. Williams entered upon the work of incorporating into 
 porcelain teeth all the perfections of natural teeth, it quickly became 
 evident that the number of subjects concerning which knowledge must 
 be crystallized and systematized was too great for one man to cover 
 the whole field. The subject of color was assigned to me for investiga- 
 tion. I have given the subject extensive study and have at least some 
 of the results in concrete form. They have been applied to Trubyte 
 teeth, and I shall try to make plain in what ways they enable the 
 prosthetist to improve the appearance of his work. 
 
 101 
 
THE COLOK SCHEME IN NATURAL TEETH. 
 
 Until one has studied the colors in natural teeth, he cannot realize 
 how complicated, how delicate and how beautiful is the color scheme 
 bj which nature adorns a reallj fine set of teeth. 
 
 When the lips are parted in smiling, so that parts of both sets are 
 seen, the teeth form a band of color which shades away in all directions 
 from the point of highest light in the incisal halves of the upper cen- 
 trals, to softer colors and shadows in the upper cuspids, bicuspids and 
 molars, and darker shades and softer shadows in the lower anteriors. 
 Nature thus introduces into the face a spot of very high light and 
 blends it away so softly that no sense of disharmony is created. 
 
 Only when the eye has time to penetrate the shadows between the 
 teeth, do the forms or sizes of individual teeth become visible. If the 
 color of the teeth is harmonious with that of the patient's complexion, 
 the general appearance will be pleasing, even if the teeth are not exactly 
 harmonious in form and size with the face. Dentists who are con- 
 fronted with the necessity of selecting teeth too large for the features, 
 other than the orifice, may do much to conceal the size, by selecting a 
 suitable color and shade. 
 
 Natural teeth exhibit every color of the rainbow. The primary 
 colors, red, blue and yellow are found in every human tooth. At least 
 one of the secondary colors, orange, green or violet is found in every 
 tooth, generally with an excess of some primary color which gives to the 
 tooth its recognized color as a blue, a yellow or a pink. Gray teeth oc- 
 cur when there is no excess of primary color. 
 
 The coloring in natural teeth is ingeniously designed to enhance 
 the value of the mechanical effects. The anteriors round outward and 
 backward from the median line. This is in harmony with the round- 
 ing away of the features, but it is rendered much more pleasing to the 
 eye by the subtle change in the colors of the laterals and cuspids. The 
 light rounds away with the form. 
 
 Nature's skill as a craftsman is exliibited in the effects which she 
 achieves by changing the depth and distribution of color in the lower 
 anteriors, as compared with the uppers. This effect greatly enhances 
 the overhanging effect of the upper anteriors, softens the contrast be- 
 tween the lower lip and the teeth, and when aided by the red reflection 
 from the lip, seems to merge tlie necks of the lower anteriors into a band 
 of soft color which serves as a base for the whole color scheme of the 
 anteriors. One can hardly appreciate the delicacy and beauty of this 
 effect until he studies a set in which the shading is strong enough to 
 be noticeable, and sees how nature has used the deep, soft colors of the 
 lower incisors and the soft shadows that fall between them, as a founda- 
 tion for the lighter colors in the upper anteriors. The most beautiful 
 sets are those in which the color scheme is so delicately worked out that 
 its elements can be recognized only by careful study. 
 
 102 
 
HOW COLOR IJs^ XATURAL TEETH WAS STUDIED. 
 
 While much has been written and more has been said about the 
 colors and shadings in natural teeth, as compared with those in porce- 
 lain teeth, nothing written could be found which was of value in ar- 
 riving at the definite, workable conclusions that are necessary when the 
 fruits of an investigation are to be incorporated into articles of manu- 
 facture. It therefore became necessary to undertake this study from 
 the beginning. 
 
 The services of experts in colors were obtained, and a number of 
 persons with beautifully colored and shaded natural teeth were selected. 
 Laboratory conditions in cleanliness of teeth, purity of light, absence of 
 shadows and reflections, and other such conditions as fine color work 
 requires, were established. 
 
 The method of measuring color values now approved by the finest 
 color analysts was adopted. This system accepts as a unit of color, the 
 smallest amount of red, yellow or blue that can be perceived by the eye 
 of an intelligent person not specially trained in color work. This depth 
 of color is marked witli the figure "1" and is multiplied to measure 
 stronger colors and divided to measure fainter colors. The experts 
 who assisted in this work, or more accurately whom I assisted, could 
 perceive and place 1/100 of a unit in any color. 
 
 By means of special appliances devised for the work, the cervical 
 half of each tooth was isolated for color measurement, and the incisal 
 half was later isolated in like manner. The anteriors, the bicuspids and 
 the first molars were measured in this way. The work is very difficult; 
 in fact, it is by far the most difficult ever attempted by these experts, 
 on account of the character of the tooth substance, and the delicacy, 
 complexity and soft blending of the shades. The dif^culties may be 
 partly appreciated when it is stated that after a steady look of 5 seconds 
 the vision is no longer true for color and that two hours of continuous 
 work exhausts a strong person for a day. 
 
 The amount of color seen in the tooth as a whole was first de- 
 termined. This color was then broken up into its component parts and 
 the proportions of the several parts determined. The work was checked 
 by making a sample color like the portion of the tooth which it repre- 
 sented. 
 
 I spent a great deal of time and about two thousand dollars of 
 The Dentists' Supply Company's money in studying and reproducing 
 tooth colors, and am able to offer what is, I believe, the first exact 
 knowledge concerning the colors of natural teeth and certainly the first 
 application of that knowledge to the manufacture of porcelain teeth. 
 Xo claim is made for originality and the work is far from being as com- 
 plete as I should like to see it. But until some one has not less than 
 two years to study tlie subject, and a large sum of money foi" the; em- 
 |)Ioyment of experts, little more can be acconi})liKhed. 
 
COLOR ANALYSIS 
 
 Miss D. A. 
 
 Age 19 
 
 Ht. 5.6" 
 
 Wt. 119 lbs. 
 
 Color Developed 
 
 Black Orange 
 
 UPPERS 
 
 U. R. Central 
 
 ' ' Ivateral 
 
 ' ' Cuspid 
 
 " 1st bicuspid 
 " 2nd " 
 " 1st molar. . . 
 
 I/. Central 
 
 ' ' Lateral 
 
 " Cuspid 
 
 " 1st bicuspid 
 " 2nd " 
 " 1st molar. . . 
 
 U. 
 
 LOWERS 
 Iv. R. Central 
 
 ' ' Lateral 
 
 ' ' Cuspid . . . . . 
 
 " 1st bicuspid, 
 L. Iv- Central . . . . 
 
 ' ' Lateral 
 
 ' ' Cuspid 
 
 " 1st bicuspid. 
 
 Eves 
 Hair 
 Skin 
 
 I Cervical \ 
 \ Incisal / 
 
 f Cervical 
 \ Incisal 
 f Cervical 
 1 Incisal 
 j Cervical 
 \ Incisal 
 f Cervical 
 1 Incisal 
 Cervical 
 Incisal 
 Cervical / 
 Incisal ^ 
 Cervical 
 Incisal 
 I Cervical 
 i Incisal 
 I Cervical 
 \ Incisal 
 f Cervical 1 
 \ Incisal 1 
 \ Cervical 1 
 I Incisal ) 
 Cervical / 
 Incisal \ 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 17.5 
 Dead 
 4.1 
 
 1.1 
 
 1.1 
 
 1.85 
 
 1 85 
 
 1.85 
 
 1.9 
 
 2.0 
 
 2.0 
 
 2.0 
 
 2.4 
 
 1.1 
 
 1.1 
 
 1.85 
 
 1 85 
 
 1.95 
 
 2.0 
 
 2.0 
 2.0 
 
 2.4 
 
 1.0 
 1.0 
 2.4 
 2.3 
 2.6 
 2.3 
 
 2.0 
 
 1.0 
 
 1.25 
 2.4 
 2 3 
 2.4 
 2.2 
 
 2.0 
 
 43.0 
 Blac 
 3.0 
 
 1.4 
 
 1.35 
 
 2.9 
 
 2,7 
 3 3 
 3.1 
 2.7 
 2.6 
 
 2.3 
 
 3.7 
 
 1 5 
 1.4 
 2.9 
 2.5 
 3.2 
 3.1 
 
 2,7 
 2.3 
 3.6 
 
 2.5 
 2.4 
 3.4 
 2.9 
 3.3 
 2.7 
 
 2.5 
 
 2.6 
 2.5 
 
 16.0 
 k 
 
 .88 
 
 .20 
 .34 
 
 1.3 
 
 1.7 
 
 1.75 
 
 1 85 
 
 1.6 
 
 1.7 
 
 1.6 
 
 2.3 
 
 .20 
 .38 
 1.3 
 1.6 
 1.75 
 1.8 
 
 1 6 
 1.6 
 2,3 
 
 .74 
 .76 
 
 1.6 
 
 1.8 
 
 1.5 
 
 1.55 
 
 1.5 
 
 .74 
 .95 
 
 1.6 
 
 1.8 
 
 1.45 
 
 1.5 
 
 1.5 
 
 16.0 
 
 .20 
 .34 
 
 1.3 
 
 1.7 
 
 1.75 
 
 1.85 
 
 1.6 
 
 1.7 
 
 1.6 
 
 2.3 
 
 .20 
 .38 
 1 3 
 1.6 
 1.75 
 1.8 
 
 1.6 
 1.6 
 2.3 
 
 .74 
 .76 
 
 1.6 
 
 1.8 
 
 1.5 
 
 1.55 
 
 1.5 
 
 .74 
 .95 
 1.6 
 
 1.8 
 
 1.45 
 
 1,5 
 
 1 5 
 
 1,5 
 2.12 
 
 25.5 yel. 
 1,1 red 
 
 .90 
 .76 
 .55 
 .15 
 .10 
 .05 
 .40 
 .30 
 
 .40 
 
 .10 
 
 .90 
 
 .72 
 .55 
 .25 
 .20 
 .20 
 
 .40 
 .40 
 .10 
 
 .26 
 .24 
 .80 
 .50 
 1.1 
 .75 
 
 .50 
 
 .26 
 .30 
 .80 
 .50 
 .95 
 .70 
 
 .50 
 
 .3 
 
 .25 
 1.05 
 
 .85 
 1.45 
 1.2 
 
 .7 
 
 .6 
 
 .3 
 
 1.3 
 
 .4 
 
 .3 
 1.05 
 
 .65 
 1.25 
 1,1 
 
 .3 
 1.2 
 
 1.5 
 
 1.4 
 
 1.0 
 
 .6 
 
 .7 
 .4 
 
 1.5 
 
 1 15 
 
 1.0 
 
 .6 
 
 .7 
 .4 
 
 104 
 
(For convenience of those not accustoniert to studying such charts, I have put the 
 colors in the right hand teeth ou the reader's right hand, and not in the reverse form 
 common to dental charts.) 
 
 
 I 1 
 
 1 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ibxJGs^^. 
 
 \:/^]gI: _:: 
 
 
 ||||||:[:^'YI 
 
 ¥-l^-J/l4lllllllllllll 
 
 ;::::: 
 
 
 
 c 
 
 If ' ' ' 
 
 1 1 
 
 r "!!! 
 
 
 
 t : 
 
 
 
 
 
 
 
 
 
 
 t ::::: 
 
 i; JL — Lj_i 1 
 
 
 
 T -X-- 
 
 it--m 
 
 
 
 -^ -i . YE 
 
 iLOW t" 
 
 ; ; 
 
 li ; 1 
 
 j_ 
 
 
 
 
 --— r-p 
 
 - 
 
 — k_ ^ -^. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 0,6 ^ 
 
 ! , i i 
 
 1 : 
 
 (- 
 
 jhi _ 
 
 0.4 - - - - . 
 
 ; ■ ; 1 : : ! 1 : 1 
 
 
 ' ' l^i l" "-" - 
 
 t-rT' 
 
 *NGE- ^-:-L_J 
 
 
 ^=r?rtr-nTTrr- 
 
 Depths of colors in the necks of the upper 
 anteriors. 
 
 Depths of colors in the incisal halves of 
 the upper anteriors. 
 
 DIAGRAMMATIC REPRESENTATION OF THE DEPTHS OF COLOR 
 TABULATED ON PAGE 104. 
 
 The different depths of color in different parts of a tooth and in different 
 teeth can be diagrammatically shown in charts like those here reproduced. 
 
 The horizontal base line of the charts represents in color. Each of the 
 parallel horizontal chart lines represents a depth of 1/10 of a unit, upward 
 from 0. The line locating the gray in the teeth is drawn solid. That represent- 
 ing the orange is drawn in dashes and that representing the yellow, in dots. 
 This set of teeth showed no other colors. 
 
 This person's hair is dead black, the eyes are brown, and the skin showed 
 a good deal of red. 
 
 The charts show that the necks of the upper centrals and laterals in this 
 set exhibit less gray than the cutting edges, but more orange and yellow. The 
 cuspids exhibit practically the same amount of gray and orange throughout 
 the teeth, but the necks show more yellow than the cutting edges. This free 
 yellow gives these cuspids their character. 
 
 The necks of one lower central and both lower laterals in this set, exhibit 
 less gray than the cutting edges, but the necks of the lower laterals exhibit 
 more orange and yellow. The lower cuspids exhibit practically an even depth 
 of gray throughout, but much more orange and yellow in the necks. There is 
 a good deal more orange in the lower cuspids than in the upper cuspids. 
 
 A_ study of these charts shows how the color deepens and softens in all 
 directions from the incisal halves of the upper centrals, and how utterly 
 impossible it is for artificial teeth all of a shade to meet the artistic require- 
 ments of prosthesis. 
 
 l»<-I'thM of lolors In tlic iiciks of tlic iowei 
 anteriors. 
 
 iS=yyb:=!:===E;; 
 
 Dcplhs of 
 
 II the iiicis.'il 
 ■r interiors. 
 
 halves of 
 
 105 
 
COLOR ANALYSIS 
 
 Miss K. B. G. 
 
 Age 31 
 
 Ht. 5.4^2" 
 
 Wt. 113 lbs. 
 
 Red 
 
 Color Developed 
 
 UPPERS 
 U. R. Central 
 
 ' ' Ivateral 
 
 " Cuspid 
 
 " 1st bicuspid. 
 
 " 2nd " 
 
 " 1st molar . . 
 U. Iv. Central 
 
 ' ' I^ateral 
 
 " Cuspid 
 
 " 1st bicuspid 
 
 " 2nd " 
 
 IvOWERS 
 Iv. R. Central 
 
 ' ' I^ateral 
 
 ' ' Cuspid 
 
 " 1st bicuspid. 
 
 " 2nd " 
 
 " 1st molar. . . 
 Li. L,. Central 
 
 ' ' Lateral 
 
 ' ' Cuspid 
 
 " 1st bicuspid. 
 
 " 2nd " 
 
 " 1st molar. . . 
 
 Eyes 
 Hair 
 Skin 
 
 f Cervical 
 
 \ Incisal 
 
 j Cervical 
 
 ( Incisal 
 
 / Cervical 
 
 \ Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 \ Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 Cervical 
 
 Incisal 
 
 16.5 
 
 17.0 
 
 4.1 
 
 2.0 
 1.8 
 2.0 
 1.8 
 2.7 
 3.6 
 
 2.7 
 2.4 
 
 3.5 
 
 2.0 
 1.8 
 1.9 
 1.8 
 
 3.7 
 3.6 
 
 2.7 
 2.5 
 
 2.9 
 1.9 
 3.0 
 1.9 
 3.6 
 2.1 
 
 3.2 
 3.3 
 
 3.4 
 
 2.7 
 2.0 
 3.0 
 1.9 
 3.6 
 2.1 
 
 3.1 
 3.3 
 
 3.5 
 
 17.5 
 
 23.0 
 
 2.4 
 
 1.8 
 1.9 
 2.5 
 1.9 
 4.2 
 4.5 
 
 2.4 
 2.1 
 
 3.3 
 
 1.8 
 1.9 
 
 2.5 
 2.2 
 4.6 
 3.8 
 
 2.5 
 2.2 
 
 3.0 
 1.7 
 3.0 
 1.7 
 3.6 
 2.0 
 
 3.1 
 3.3 
 
 3.3 
 
 2.9 
 1.8 
 3.0 
 1.7 
 3.6 
 2.0 
 
 3.1 
 3.3 
 3.3 
 
 13.5 
 14.0 
 .70 
 
 1.9 
 
 1.8 
 
 1.55 
 
 2.4 
 
 2.2 
 
 2*5 
 
 1.7 
 1.6 . 
 
 2.9 
 
 1.9 
 
 1.25 
 1.55 
 1.5 
 
 2.3 
 2.5 
 
 1.7 
 1.6 
 
 2.2 
 1^7 
 2.2 
 1.7 
 2.4 
 1.9 
 
 2.2 
 2.3 
 
 2.6 
 
 1.9 
 1.8 
 2.2 
 1.7 
 2.4 
 1.9 
 
 2.2 
 2.3 
 2.5 
 
 13.5 
 14.0 
 .70 
 
 1.8 
 1.8 
 
 1.55 
 1 8 
 2.2 
 2.5 
 
 1.7 
 1.6 
 
 2.9 
 
 1.8 
 1.25 
 1.55 
 1.5 
 
 2.3 
 2.5 
 
 1.7 
 1.6 
 
 2.2 
 1.7 
 2.2 
 1.7 
 2.4 
 1.9 
 
 2.2 
 2.3 
 
 2.6 
 
 1.9 
 1.8 
 2.2 
 1.7 
 2.4 
 1.9 
 
 2.2 
 2.3 
 2.5 
 
 3.0 or. 
 3.0 " 
 1.7 " 
 
 .1 vio. 
 
 .45 or. 
 .1 gr. 
 .5 or. 
 1.1 " 
 
 .4 " 
 
 .1 vio. 
 
 .55 or. 
 
 .35 " 
 
 .3 " 
 
 1.4 " 
 
 1.1 " 
 
 1.2 
 .1 
 
 .9 
 1.0 
 
 .7 
 
 1.2 
 .1 
 
 .9 
 1.0 
 
 1 . yel. 
 6.0 " 
 1 . 7 red 
 
 .Ired 
 .1 yel. 
 .5 " 
 .5 blue 
 1.5 yel. 
 .9 " 
 
 .3 red 
 .3 " 
 
 .2 " 
 
 .1 " 
 . 1 yel. 
 .6 " 
 .4 " 
 .9 " 
 .2 " 
 
 .2 red 
 .3 " 
 
 .1 yel. 
 .2 red 
 
 .2 yel. 
 .2 red 
 
 .2 " 
 
 .1 " 
 
 106 
 
(For convenience of those not accustomed to studying such charts, I have put the 
 colors in the right hand teeth on the reader's right hand, and not in the reverse form 
 common to dental charts.! 
 
 Depths of colors in the necks of the upper Depths of colors in the incisal halves of 
 anteriors. the upper anterlors. 
 
 DIAGRAMMATIC REPRESENTATION OF THE DEPTHS OF COLOR 
 TABULATED ON PAGE 106. 
 
 The patient's hair and eyes are of very nearly the same depth of brown, 
 except that the eyes have more of a yellow tinge. The excess of red in the 
 skin renders it very light. 
 
 The teeth differ from those charted on the foregoing page in that the pro- 
 portion of red is greater, sometimes enough so that it remains as a free color 
 and gives the teeth a pink shade. 
 
 The upper right central is of even depth of gray throughout. The color in 
 the neck is much softened by the presence of violet and red, while the incisal 
 half exhibits free yellow. The upper left central exhibits much deeper gray 
 in the neck than in the tip. It shows violet and red in the neck but only gray 
 in the cutting edge. 
 
 The upper right lateral exhibits deeper gray in the tip than in the neck, 
 but the neck exhibits orange which is lacking in the tip, and the yellow is much 
 deeper in the neck than in the tip. The upper left lateral is of even gray 
 throughout, and shows orange and j^ellow in the neck. The tip is of pure gray. 
 
 The upper right cuspid is of deeper gray in the tip than in the neck, but 
 the neck exhibits orange which is lacking in the tip, and the yellow is much 
 deeper in the neck than in the tip. The upper left cuspid shows slightly mors 
 gray in the tip than in the neck, but the neck shows deep orange and con- 
 siderable yellow. 
 
 The necks of the lower anteriors show much more gray than do the tips, 
 and this depth of color is increased by the presence of considerable orange. 
 The color in the incisal halves of the lower centrals and laterals is deeper than 
 in the incisal halves of the upper centrals and laterals. 
 
 '■'■ '■'■'■'- lot- ' 
 
 ■b 
 
 
 nrio 
 
 mm 
 
 "] 
 dL 
 
 i . ' o w 
 
 De[)thH of colorH in tlie necks of the lower iKpths of colors in llic iiicis.il halves of 
 •interiors. 'Ill' lower iiiitcriors. 
 
 107 
 
(For convenience of those not accustomed to studying such charts, I have put the 
 colors in the right hand teeth on the reader's right hand, and not in the reverse form 
 common to dental charts.) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 !S 
 
 5 -^-1 - 
 
 / -,-- 
 
 
 
 V - 
 
 -k- \t 
 
 ' 1 
 
 
 
 \- 
 
 -\ it 
 
 t 
 
 
 
 j - 
 
 .2__3£_- 
 
 .--t 
 
 
 
 ^^^^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
 
 
 , , 
 
 
 
 i. .. .. .1 
 
 
 
 vif'ifiw ■^■^■S.. 
 
 ' ■! 
 
 ._^„,„_ 
 
 
 
 1 1 
 
 L ..J 
 
 
 
 
 
 
 
 
 ?6 
 
 
 
 
 
 - . 
 
 1 >■ 
 
 
 
 
 ¥ " " 
 
 
 
 
 
 o5 " " 
 
 1 
 
 
 
 
 t;;= 
 
 —±------^ 
 
 
 
 
 Depths of colors in the necks of the upper 
 anteriors. 
 
 \s:t _, 
 
 01 
 
 iiiii 
 
 RANGE- 
 
 YEtltOW 
 
 IJfc 
 
 Depths of colors in the incisal halves of 
 the upper anteriors. 
 
 DIAGRAMMATIC REPRESENTATION OF THE DEPTHS OF COLOR 
 IN A SET OF TEETH NOT TABULATED. 
 
 The anteriors of this set of teeth exhibit only gray, orange and yellow. 
 The depth of gray is so nearly uniform in the necks of the upper anteriors, 
 that it varies only 1/10 of a unit from central to cuspid. The orange is un- 
 usually deep in the necks of the centrals and still deeper in the laterals and 
 cuspids. The yellow is much deeper in the neck of one lateral than in the 
 other, and is strong in the cuspids. 
 
 The gray and yellow are practically as deep in the incisal halves of the 
 upper incisors as in the necks, but the orange is only half as deep. There is 
 only half as much yellow in the incisal halves of the upper cuspids as in the 
 necks, and about 2/3 as much orange. 
 
 The lower incisors exhibit practically a uniform depth of gray in necks 
 and incisal halves, but there is less orange and a good deal less yellow in the 
 incisal halves. The lower cuspids are of nearly uniform color throughout, 
 and exhibit deeper color than any of the other anterior teeth. 
 , The above colors combine to produce a set of natural anteriors of a grayish 
 yellow cast, with enough red in the color to give brilliance. The lower an- 
 teriors are darker than the uppers and serve as a base for the color scheme. 
 The incisal halves of the upper centrals form the spot of high light, and the 
 color deepens beautifully into the necks of the upper centrals. The color 
 deepens gradually and effectively through the upper laterals and cuspids. 
 
 Depths of colors in the necks of the lower 
 anteriors. 
 
 Depths of colors in the incisal halves of 
 the lower anteriors. 
 
 108 
 
HOW THE COLORS ARE PLACED IN XATURAL TEETH. 
 
 Xatiire exhibits in the coloring of the teeth the infinite variety of 
 her other works, is^o two sets exhibit exactly the same depth or location 
 of color, and no two teeth in any of the sets studied are exactly alike. 
 Indeed, the depth of color in the teeth on one side of the mouth is often 
 different from that on the other. 
 
 Those sets of natural teeth in which the colors blend so softly that 
 the separate parts of the color schemes are seen only when studied, are 
 most beautiful. Others are more striking, but after a time they seem 
 less pleasing, because of the strong contrasts. 
 
 In order that Trubyte teeth might exliibit the colorings of the 
 £nest sets of natural teeth, an average of the colorings in several beauti- 
 ful sets has been made and incorporated into the porcelain. 
 
 In finely colored sets of natural teeth, the incisal halves of the up- 
 per centrals, taken together, form the spot of highest light in the face, 
 except the white of the eyes, which is so sheltered as not to form a 
 striking point. The shade usually deepens as one goes toward the 
 necks of the teeth, though this is not always the case. Centrals which 
 are lighter in the incisal halves carry out better the color scheme of the 
 teeth as a whole, than those with darker cutting edges. The two centrals 
 exhibit minute differences of color, but the color effect as a whole is 
 very much alike in the two teeth. 
 
 The color in the upper laterals is usually deeper than that in the 
 centrals and it is more evenly distributed throughout the area of the 
 tooth. The incisal half of the lateral is therefore of deeper shade than 
 the incisal half of the central. The two upper laterals are rarely ex- 
 actly alike. 
 
 The color in the upper cuspids is nearly always deeper in shade 
 than in either the centrals or the laterals. The neck is sometimes much 
 deeper than the incisal half, sometimes but little deeper, and sometimes 
 the tooth is nearly of uniform color throughout. The finest cuspids 
 are undoubtedly those in which the color is deeper in the cervical half. 
 
 The color deepens through the bicuspids and molars, in some cases 
 more rapidly than in others. Those sets are most beautiful in which 
 it deepens softly. The sets in which it deepens very rapidly appear too 
 deeply colored at the cervical margins. 
 
 The color in the incisal halves of the lower incisors is deeper than 
 in the incisal halves of the upper anteriors. The color in the necks is 
 deeper than in the incisal edges. The lower cuspids usually present 
 deeper colors than the incisors in both the cervical and incisal halves. 
 
 Xature seems to appreciate that the color scheme of the teeth does 
 not usually contemplate the exhibition of the lower bicuspids and 
 molars and they present no noticeable differences from similar upper 
 teeth. 
 
 109 
 
THE VAGAKIES OF COLOR IK KATUEAL TEETH. 
 
 These illustrations show, in pictorial form, the colors present in 
 one set of natural anterior teeth ; their locations in the several teeth and 
 their relative densities. The color was measured for each half of each 
 tooth. 
 
 This is not one of the sets previously illustrated. 
 
 GRAY 
 
THE VAGARIES OF COLOR IX XATURAL TEETH— Cont. 
 
 The secondary colors, shown on the opposite page, are nearly always 
 accompanied by an excess of one or more primary colors and this excess 
 of color gives the teeth their character. The three primary colors 
 were in evidence in this set as follows : 
 
 RED 
 
 111 
 
COLOES AND SHADES 11^ OEDII^ARY ARTIFICIAL TEETH. 
 
 Artificial teeth, as regularly furnished, have heretofore been of 
 one shade throughout the full upper and lower sets. This has made it 
 impossible for dentists to select a shade which was satisfactory for the 
 high lights in the upper centrals and the deeper colors in the other teeth. 
 
 Individual dentists have made efforts to change this condition by 
 grinding or staining teeth, or by selecting teeth from different shades 
 and assembling them into one set. In the hands of a few dentists the 
 staining method has yielded beautiful results, but the time and skill re- 
 quired for each case were such as rendered a high fee necessary. The 
 method of selecting teeth of different shades is rarely satisfactory 
 because the different shades in any shade guide were not intended for 
 such selection, and teeth assembled from such shades show variations 
 unlike those in fine natural teeth. Moreover, the method requires the ex- 
 penditure of much time and access to a large stock of teeth. 
 
 ISTaturally shaded artificial teeth have never been available before 
 for three reasons, which come directly home to us as dentists. The first 
 is that we have never offered any intelligent plan for the coloring of 
 teeth. We have left it to manufacturers who are not dentists, and who 
 cannot see our work as we see it, to solve the difficult problems as to 
 what true tooth colors are and how they are placed. 
 
 The second reason is that we have not known when teeth were 
 properly shaded. I persuaded certain manufacturers to shade very 
 beautifully 100 sets of vulcanite teeth and send them out in the regular 
 course of business, without any comment. Some of them were accepted 
 without remark. Others were returned with the comment that if the 
 manufacturer could not match teeth better than that, the dentists would 
 trade elsewhere. ]^ot a single favorable comment was received. Our 
 attitude as a profession has been that we were entitled to ask for a thing 
 and then to leave the manufacturer to find out what we need, how to 
 make it and to educate us to an appreciation of it when made. Such 
 an attitude is not worthy of us, and we are entitled to make little com- 
 plaint if the solutions of the past have not been to our liking. 
 
 The third reason is hardly less strong than the other two. Most 
 of us have been unwilling to pay for the production of superior products. 
 We know so little of our own costs of production, that we do not under- 
 stand why fine articles cannot be produced for the same price as ordi- 
 nary articles. It is economically impossible. The superior quality 
 results from the application of a greater amount of intelligence and 
 skill. That demands more time, and more wages and slower produc- 
 tion. 
 
 112 
 
COLOKS AXD SHADES IX TRUBYTE TEETH. 
 
 Tnibyte teeth are "shaded" in the sets, on the basis of extensive 
 data similar to that described in the foregoing pages. They are made 
 in all of the 25 shades on the Twentieth Century Shade Guide. 
 
 The upper central is always of the shade on the Guide. The shad- 
 ing of the set is accomplished by varying the depth of this color. Xo 
 other colors are added to get the effects. 
 
 The color in the upper laterals is more evenly distributed through- 
 out the tooth, as was described in connection with natural laterals. 
 The upper cuspids are more deeply shaded in both cervical and incisal 
 halves than either the centrals or laterals. The color in the bicuspids 
 and molars deepens softly. 
 
 The shade in the incisal halves of the lower anteriors is deeper 
 than that in the incisal halves of the upper anteriors, while the color in 
 the necks is deeper still. This permits the artistic effect of the over- 
 hanging upper teeth to be achieved, and builds up the color scheme as 
 has been described. I believe this to be the first time that this beauti- 
 ful color scheme has ever been applied to porcelain teeth produced in 
 commercial quantities and available to all dentists. 
 
 All teeth may be ordered from the number on the Shade Guide. 
 The only dift'erence from the teeth heretofore furnished will be that 
 teeth, crowns and facings for laterals, cuspids, bicuspids and molars, will 
 be properly shaded. 
 
 Great artistic and economic advantages result from this shading : 
 
 It is unnecessary to stain teeth, save in rare cases. The colors in 
 the tooth are finer than can be gotten by staining. The teeth are avail- 
 able without any loss of time and at surprisingly low cost considering 
 the additional cost of production. 
 
 It is unnecessary to select teeth of different shades and assemble 
 them into a set. Teeth thus assembled cannot exhibit the beauty of 
 coloring found in these teeth. Xo time need now be lost in such selec- 
 tion. 
 
 Dentures made with properly shaded teeth are artistically so su- 
 perior to those made with teeth all of one shade, that no comparison 
 can well be made. 
 
 The beauty of a fine arrangement is greatly increased. 
 
 We are enabled to offer to appreciative patients, the finest product 
 of our time for all prosthetic work requiring porcelain. Such work 
 demands a fee commensurate with the results. And many of us who 
 have hesitated to ask remunerative fees for prosthetic work because we 
 were not satisfied witli the appearance of our own work, may now have 
 the confidence to undertake such work with pleasure and with the cour- 
 age to dfrnniifl adequate reward. 
 
 113 
 
SUGGESTIOXS FOE SELECTIXG COLOES AXD SHADES. 
 
 "While the teeth exhibit much less color than the skin, the iris of 
 the eves, and the hair in most cases, they exhibit much deeper colors 
 than appear when contrasted with the skin. And few dentists have the 
 courage to select artificial teeth with sufficient depth of color. 
 
 Useful information about the colors in teeth may be gained by 
 forming dark paper into a roll about an inch in diameter and ten inches 
 long, shaping one end to fit about the eye to exclude the side lights, 
 and covering the other end of the tube with dark paper in the center 
 of which is a hole about ys inch in diameter. 
 
 Seat the patient in good but not brilliant liglit and in such man- 
 ner that neither the natural teeth nor the shade teeth exhibit shadows 
 or reflections. Reflections from brightly colored walls sometimes 
 change the color seen. Apply the paper tube to the eye and isolate the 
 tooth to be matched from all others and from the lip. This permits one 
 to perceive the color more truly. When the color is determined, select 
 the sample tooth of the proper color by trying in the usual manner, 
 beginning w^ith the darkest. Beware of light colors and shades. Use 
 them only when certain that nothing else will appear so well in the 
 mouth. The basic color in all teeth is gray. It is most commonly 
 affected liy yellow, so that the color is really a yellow built on a gray 
 base. It is sometimes affected toward the blue, and in rare instances 
 toward red or green. 
 
 Dentists who distrust their own skill in selecting shades will be 
 greatly aided by the natural shading in Trubyte teeth. This helps to 
 hide any slight error in shade and makes the laterals and cuspids 
 appear more natural than is possible with teeth all of one shade. This 
 will be found especially helpful in the selection of facings and porcelain 
 crowns. 
 
 When teeth for full dentures are to be selected, the dentist should 
 select a color and shade that harmonize with the skin of the lip. All 
 reference to the hair and eyes can be omitted, for they show such ex- 
 treme variations of color, that no rules can be laid down for establish- 
 ing harmony with all three. 
 
 If the skin is examined through the paper tube, it will often be 
 found to exhibit a surprising amount of red. In such cases, teeth with a 
 good deal of life in the color, as in Twentieth Century Shades 7 and 9, 
 will of^ten be found suitable. When the color in the skin is deeper, the 
 color in the teeth should be deeper. 
 
 A shade guide of the same make as the teeth to be used should al- 
 ways be employed in selecting shades. Shade Guides may now be had 
 on such liberal terms that a dentist should always have on hand at least 
 two of his favorite make, in order that in very particular cases the 
 sample tooth may be sent with the order for more exact matching. 
 
 114 
 
A TAI5LE OF THE C'OLOlfS IX THE TWENTIETH CENTURY 
 
 SHADE GUIDE. 
 
 Sliade Xo. 1. Lightest shade in use. So coloi-inj^'. 
 
 Shade Xo. 2. Trace of purple. 
 
 Shade Xo. •'). Trace of l)hie. Trace of yellow. Liiihtest blue. 
 
 Shade Xo. 4. Trace of yellow. Lightest yellow. 
 
 Shade Xo. 5. "^rrifle of gray and trace of yellow. Point saiiu! 
 as Xo. 4. X'^eck darker. 
 
 Shade Xo. 0. Same as Xd. 4, wirh ;i linlc gray in tin; rip. Xeck 
 not so bright a yellow as Xo. 5. Lightest gray. 
 
 Shade Xo. T. Light yellow. Darker than X"o. 5, wMtli color 
 decidedly stronger in neck. 
 
 Shade X'o. S. Light yellow. Tij) darker than Xo. .". oi' Xo. 7. 
 X'eck lighter than X'o. 7, and makes tooth look a straw coloi'. More 
 uniform than X^o. 7. Yellow is the only color present. 
 
 Shade X'o. 1). A little yellow, a little gray, a little j)ink. Light 
 brown yellow neck. Tip pink gray, follows X^o. IL 
 
 Shade Xo. 10. Gray. Lighter than Xo. ••>. Darker than Xo. 0. 
 
 Shade Xo. 11. Uniform gray throughout. X'eck grayish yel- 
 low slightly darker than 10, which it follows. 
 
 Shade Xo. 12. Grayish blue. Follows Xo. •'> in the hhies. 
 
 Shade Xo. 13. Grayish blue. Follows Xo. !). 
 
 Shade X'o. 14. Yellowish gra\'. Cirav vellow neck. Follows 
 Xo. 1.3. 
 
 Shade XTo. 15. Pinkish gray. Decidedly darker and shows more 
 pink than X^o. 1». The other grays are bluish grays. This follows 
 X'o. 14. 
 
 Shade X'o. 10. Yellow. Follows X'o. 8. 
 
 Shade X'o. 17. Greenish yellow. Green tip and yellow neck. 
 
 Sliade X'o. IS, Dark yellowish gray. Follows Xo. 14. 
 
 Shade X'o. li>. Dark gi-eenish yellow. Follows X'o. 17. 
 
 Shade Xo. 20. Brownish yellow. Follows Xo. 16. 
 
 Shade Xo, 21. Dark brown yellow. Follows Xo. 20, which it 
 is like, only darker. 
 
 Shade X^. 22. Dark gray. Follows Xo. 18. 
 
 Shade Xo, 23. Darkest brown yellow. Follows Xo. 21. 
 
 Shade X"o. 24. Dark grayish brown. P^dlows Xo. 22. 
 
 Shade X'o. 25. Dark yellowish brown. Follows Xo. 23. 
 
 (Light shades, 1-2. 
 ^'ellows, 4-5-7-8-10-1 7-1 1>-20-21-23-25. 
 firays, 0-10-11-0-13-14-15 lS-2-24. 
 lilues, 3-12. 
 
 115 
 
EITAMEL MAEKIi^GS 11^ :^rATUEAL ANB PORCELAIN" 
 
 TEETH. 
 
 The labial surfaces of the finest specimens of natural teeth are not 
 smooth, but are marked by a series of fine, horizontal striations, which 
 vary in character in different parts of each tooth. 
 
 These markings break up and diffuse the light, so that portions of 
 it from all surfaces are directed away from the eye, while portions of 
 it from all surfaces reach the eye. The effect is to soften both the bril- 
 liant lights and the shadows. In natural teeth in which the labial 
 surfaces have been worn smooth, the light is not so diffused. The teeth 
 have a hard look, and it is concerning such teeth that criticism is some- 
 times passed that they must be false. 
 
 Artificial teeth in the past have exhibited smooth labial surfaces, 
 sometimes broken by strong developmental grooves, or horizontal 
 grooves, probably intended to represent defective calcification. Such 
 grooves, however, were not of the character required to diffuse the light 
 and give to the teeth a natural appearance. 
 
 Artificial teeth have looked false partly because the surfaces have 
 been too glassy and because they have reflected strong high lights sur- 
 rounded by deep shadows. Such teeth cannot be made natural in ap- 
 pearance. 
 
 In connection with the studies in color, I took up the study of 
 the markings in anterior teeth. With the co-operation of Dr. Williams 
 and Prof. Grysi, the most satisfactory forms of markings for reproduc- 
 tion in porcelain teeth were determined. The methods in use for the 
 production of the ordinary porcelain teeth could not produce teeth with 
 the desired markings. The manufacturer undertook the invention of 
 methods which should produce the required results. After two years 
 of experimentation, the methods were perfected and teeth with proper 
 markings produced. Teeth with these markings are superior to teeth 
 without them for the following reasons : 
 
 The markings are anatomically correct and produce the proper dif- 
 fusion of light. 
 
 The diffusion of light greatly softens the appearance of the teeth, 
 so that teeth with the markings appear more like fine natural teeth than 
 teeth of identical size, color and porcelain without the markings. 
 
 The high lights on each tooth are greatly softened and the glassy 
 reflection is taken away. 
 
 The shadows are softened so that the teeth do not present such 
 strong contrasts of light and shade. 
 
 The shading in the teeth is greatly enhanced in naturalness and 
 value. 
 
 The color scheme in each set of anterior teeth and in the two sets 
 can be very much better reproduced by the dentist in crowns, facings 
 and Aadcanite teeth. 
 
 116 
 
PART IV. 
 
 Efficiency In 
 Bicuspids And Molars 
 
FOREWORD. 
 
 With the exception of the anatomical forms offered by The Den- 
 tists' Supply Company, the porcelain bicnspid and molar teeth of the 
 past seem to have been designed to afford the smallest possible amount 
 of efficiency in mastication. 
 
 The best of them have been copies of well worn natural teeth which 
 are efficient only when firmly supported by healthy tissues and imder 
 a pressure of from 150 to 300 pounds. The others have been conven- 
 tional forms which could be articulated only by such grinding as de- 
 stroyed any possibility of masticating efficiency. 
 
 Professor Gysi believes that well made full dentures are incapable 
 of exerting more than 18 or 20 pounds of pressure. Tt is evident that 
 teeth which function only at a pressure of, say 150 pounds, cannot be 
 efficient at a pressure of 18 pounds. 
 
 Professor Gysi has demonstrated that efficient forms of porcelain 
 bicuspids and molars can be shaped only by applying nature's engineer- 
 ing principles to the formations of the occlusal surfaces, with such 
 modifications as the movable bases and slighter pressure require. He 
 has applied these principles to the production of Trubyte bicuspids and 
 molars, which are joined with Trubyte anteriors to make full sets. 
 Such teeth cannot Ix- ]>rodiiced by copying natural teeth because while 
 natural teeth present all the necessary factors at different times in their 
 history, they never present all those factors at any one time. 
 
 With Professor Gysi's permission, and by the aid of his illustra- 
 tions, r have here set forth in my own words the principles which un- 
 derlie the formation of correctly formed porcelain l)icuspids and molars. 
 
 119 
 
THE FUNCTIONS OF THE ITATUKAL BICUSPIDS AND 
 
 MOLAES. 
 
 Before we can determine the requirements for efficiency in arti- 
 ficial teeth, we must understand the plan by which nature causes the 
 natural teeth to discharge the several functions of mastication, and the 
 tasks of the four groups of teeth in each half of one jaw. 
 
 Eor the natural teeth are divided into groups by difference of 
 function quite as effectually as they are by formation. Indeed the two 
 go together. 
 
 The incisors are intended to bite the food from the mass. 
 
 The cuspids are the guides of the motion of the anterior part of 
 the jaw in lateral movements, and the shock absorbers in mastication. 
 
 The bicuspids are the crackers of all hard and brittle foods and the 
 tearers and separators of fibres. 
 
 The molars are designed to cut uj) the separated fibres, to isolate 
 the individual cells and crush the cell walls to permit insalivation of 
 the contents. 
 
 All teeth take part in crushing out the fluid portion of foods. 
 
 The buccal and lingual cusps of well articulated natural molars 
 interdigitate so perfectly, on the "working side" during lateral occlu- 
 sion, as to prevent the escape of solid portions of food. On the opposite 
 side, the proper cusps articulate to maintain balance. The cusps of both 
 sides articulate to maintain balance in the incising bite. 
 
 The occlusal surfaces permit the escape of semi-fluid portions of 
 food from between grinding cusps, and ready escape of fluid portions of 
 food. 
 
 Artificial teeth which are to be efficient in mastication must dis- 
 charge these functions. 
 
 120 
 
Fig. 58. 
 Cracking action of bicuspids. 
 
 Fig. 59. 
 Dotted line shows position of section of molars. 
 
 n 
 
 Fig. CO. 
 
 Diagram of tlie ridges of the molars at dotted line in Fig. 59 which cut food. 
 Slightly exaggerated. 
 
 Fig. Gl. 
 
 The ridges as they api)ear in ponelain before tlie fac'ts are sharpened by grhuling 
 with carborundum and glycerine. 
 
 121 
 
MODIFICATIONS OF IsTATUKAL FORMS NECESSARY IN 
 PORCELAIN TEETH. 
 
 The fact that teeth for dentures and bridges will be mounted on 
 bases which are either movable or less in number and strength than the 
 full number of roots in healthy tissues, makes it impossible for them to 
 transmit the heavy pressures possible to natural teeth. Probably dent- 
 ures cannot exert more than 1/10 of the average power of healthy nat- 
 ural teeth, and bridges from Y4 to possibly Yi. This great difference in 
 transmitted power requires certain changes in form to make the porce- 
 lain teeth efficient at small pressures. 
 
 The relatively broad opposing planes of well worn natural teeth 
 cannot be made efficient at the pressure possible to dentures and bridges, 
 because not enough power can be exercised to force such large areas to 
 tear, cut and grind the food. A larger number of small, relatively sharp 
 areas must be substituted for the few large ones, and these must inter- 
 act, as between uppers and lowers, in such way as to discharge the 
 proper cutting and grinding functions. 
 
 The cusps must be high, as they are in newly erupted teeth, but 
 with the important difference that the depth of bite must be less than 
 in any sharp natural teeth, in order that dentures and bridges may not 
 be dislodged by lateral stress. 
 
 The three molars in the perfect natural denture must be replaced 
 by two in the artificial denture, requiring some modification in form. 
 
 The fossae must be deep to permit escape of partly ground food 
 from between the cusps but not from between the teeth. The sulci must 
 be deep to permit the rapid escape of fluids and a shallow bite. 
 
 The teeth must be so carved as to be easy to arrange on any articu- 
 lator or for any case and to render the best service possible under the 
 conditions, when the dentist desires to merely occlude them and not to 
 articulate them. 
 
 WHAT CONSTITUTES DEPTH OF BITE. 
 
 The depth of bite is the distance the teeth move vertically in articu- 
 lation. 
 
 There are three depths of bite to each tooth, the "working" bite, 
 the "incising" bite and the "balancing" bite. 
 
 The working bite is the shallowest and the balancing bite the deep- 
 est. The incising bite is between the two. 
 
 The working and balancing bites are described on the following 
 pages. The incising bite needs no description. 
 
 122 
 
FIVE STAGES OF WEAR OF NATURAL TEETH. 
 
 A. Unworn Stage. Newly erupted natural teeth exhibiting high cusps and 
 deep fossae and sulci with deep bite. These teeth are efficient with the relatively 
 small muscular power of the child, but have not been worn to perfect articula- 
 tion. The bite is far deeper than is practicable in artificial teeth. 
 
 B. Gkeate.st Ekficip;xcy Sta(;e. Natural teeth worn to the stage of greatest 
 efficiency. Wear has shaped sharp edged facets on the cusps, which are very 
 efficient in cutting up fibres and in providing rolling surfaces for grinding cells. 
 This is the stage of wear reproduced in Trubyte teeth. The bite in the natural 
 teeth at this stage is deeper than can be advantageously employed in artificial 
 teeth. 
 
 C. Reuuced Efficiency Stage. Wear has formulated such broad opposing 
 planes on the molars that they can be forced through the food only by the 
 exercise of great power. The cutting action of the molars is now limited to 
 the action of the edges of the few sulci. In persons of great muscular power, 
 these teeth will be efficient in grinding. 
 
 The bite has been worn shallow but the opposing areas are much too broad 
 to be forced through food by the exercise of the relatively slight power possible 
 to dentures. 
 
 This is about the degree of wear which has been advocated for the forms of 
 artificial teeth. Such formations for porcelain bicuspids and molars is now 
 known to make efficiency impossible to the dentures. 
 
 D. Mi( H Wou.\ STACiE. The bite is shallow but the opposing areas are 
 broad and require the exertion of great force to make them efficient. 
 
 E. Stage of Extkkme Weak. Tlio cutting power is possible only by the 
 making of extreme movements and the exercise of great force. 
 
 Trubyte terth exliibit the stage of wear shown in Figure Aand the depth of 
 bite Hliown in Figure j/. IJ) 
 
 123 
 
THE WOKKING BITE. 
 
 The depth of this bite is the distance the lower teeth on the work- 
 ing side move vertically in passing from the position of central occlu- 
 sion to that of lateral occlusion, or vice versa. 
 
 The distance the teeth move vertically is determined by the degree 
 of vertical inclination of the occlusal grooves of either set as they pass 
 from the main longitudinal groove, upward over the buccal or lingual 
 margin of the tooth. 
 
 Figure 65 on the opposite page represents cross sections of Trubyte 
 upper and lower molars in central occlusion. JSTote that the upper 
 lingual cusp does not reach the bottom of the fossa in the lower tooth, 
 and the lower buccal cusp does not reach the deepest part of the fossa 
 in the upper tooth. When these teeth move into a position of lateral 
 occlusion, as shown in Figure 68, the slightly inclined buccal groove on 
 the lower tooth articulates with the relatively flat lingual incline of the 
 buccal cusp of the upper tooth, and causes the lower teeth to move verti- 
 cally downward, through the distance from Point 1 to Point 2. The 
 slightly inclined lingual groove on the lower tooth articulates with the 
 upper lingual cusp. This does not increase the vertical movement of 
 the lower teeth. 
 
 The movement of the whole jaw is illustrated in Figure 67. The 
 lower central incisor has moved downward from the position occupied 
 by the dotted outline of that tooth. The depth of the bite in the first 
 molars is here less than in the incisors, and is equal to the vertical dis- 
 tance from the Point 1 to Point 2. 
 
 The relative vertical distances moved by the central incisor and 
 the left condyle are shown in Figure 69. It will be seen that the condyle 
 has moved downward very little. This movement, combined with the 
 movement of the molars through the opposing grooves, as shown in 
 Figure 68, results in the working bite being very shallow, provided the 
 teeth are carved to articulate properly. 
 
 Figure 70 illustrates the movements of the several parts of the 
 condyles and teeth in extreme lateral position as seen from the side and 
 from above. The left condyle has moved strongly out of the fossa, 
 while the right condyle has moved forward and inward. This lateral 
 movement has an important influence on the depth of bite. When it 
 is present in considerable degree the bite is shallow. When it is absent, 
 the bite is required to be deeper to maintain the necessary relations 
 between the dentures. 
 
 The depth of the working bite in Trubyte teeth has been deter- 
 mined on an engineering basis. It is much shallower than in any good 
 specimens of natural teeth, or any other artificial teeth which even ap- 
 proach the principles of efficiency as here laid down. It is adapted to 
 the average inclination of the downward path of the condyle (33 de- 
 grees) the average inclination of the inward lateral path (16 degrees) 
 and the inclination of the incisor incline most advantageous in artificial 
 teeth (40 degrees). 
 
 (Continued on Page 126) 
 
 124 
 
The depth of the working 
 bite is from 1 to 3. 
 
 BALANCING 
 BITE 
 
 ^pWORK 
 / BITE 
 
 ING 
 
 Fig. 66. 
 Uelations of the first molars in working bite. 
 
 WORKING BITE LEFT SIDE 
 Fig. t)7. 
 
 Fig. OS. 
 
 Note articulation of cusps 
 
 and grooves. 
 
 'M-1 
 
 = 1:2 
 
 Fig. CD. 
 ln<i.sor and condyle movements in working bite. 
 
 /J BALANCING 
 ^ BITE 
 
 Fig. 70. 
 I£ — VVrtlcal movement of iidvanclng condyle. 
 L— Vertlcjil movement of stationary condyh'. 
 In the icutor ;i diagram of molar ainl Incjsor movements in extreme lateral occlusion 
 
 125 
 
Proper!}^ articulated Trubyte teeth will be found to move vertically 
 a shorter distance than any other teeth in the working bite, and to prac- 
 tically preclude the occurrence of undue lateral strains on dentures or 
 abutments. 
 
 It is not necessary to provide bicuspids and molars with different 
 depths of bite for different inclinations of the condyle paths. When the 
 teeth have been articulated, the necessary changes in the occlusal sur- 
 faces can be easily and quickly made by grinding the sets together with 
 carborundum powder and glycerine. This process, Avhich should be 
 followed in all cases, will make adaptations which could not be made in 
 carving or by other forms of grinding. 
 
 THE BALANCING BITE. 
 
 The depth of this bite is the distance the lower teeth on the balanc- 
 ing side move vertically to maintain balancing relations between the 
 dentures during articulation. It is much greater than the depth of the 
 working bite, because the steep lingual inclines of the lower buccal cusps 
 articulate with the steep inclines of the lingual cusps of the upper teeth, 
 and because the lower cusps often travel directly across the steepest 
 parts of the upper cusps instead of following the sulci. 
 
 Figure Xo. 71 on the opposite page shows upper and lower Trubyte 
 molars in central occlusion. "D" equals the depth of bite. 
 
 In Figure Xo. 72 the left lower molars have moved into the posi- 
 tion of the extreme balancing bite, through the vertical distance 1-3 
 in Figure Xo. 71. 
 
 Figure Xo. 73 shows the relations of all the teeth on the balancing 
 side. The lower jaw has moved downward to the right, away from the 
 observer. The buccal cusps of the lower bicuspids have climbed the 
 lingual cusps of the upper bicuspids. The middle buccal cusp of the 
 lower first molar has climbed the mesio-lingual cusp of the upper first 
 molar. The m6sio-buccal cusp of the lower second molar has climbed 
 the disto-lingual cusp of the upper first molar. The distal buccal groove 
 of the lower second molar has climbed the long lingual cusp of the up- 
 per second molar. 
 
 Figure Xo. 74 shows the vertical distance which the condyle on the 
 balancing side has traveled downward from its position of rest in cen- 
 tral occlusion. 
 
 Figure Xo. 75 shows the movements of the two condyles as seen 
 from the side and the movements of the condyles and teeth as seen from 
 above. The lateral movements of both condyles are here plainly shown. 
 
 Different inclinations of the condyle and incisor paths require only 
 minute adaptations of the teeth to the balancing bite. Such adapta- 
 tions cannot be well made by carving or grinding with a stone, but they 
 can be quickly made by rubbing the articulated sets together in carbor- 
 undum powder and glycerine. 
 
 126 
 
Ecr; 
 
 Fig. 71. 
 Depth of balanfiug bite is; frdin 1 to 
 
 Fig. 72. 
 Relations of first molars in balancing bite. 
 
 = 1:3 
 
 BALANCING BITE LEFT SIDE 
 
 Fig. 7:;. 
 The centrals have moved from the position shown by the central in dotted outline. 
 
 Fig. 74. 
 A'ertii'al dcptli of condyle and incisor movements in the balancing bite. 
 
 BALANCING 
 BITE 
 
 U 
 
 -(^WORKING 
 ^ BITE 
 
 Fig. 7.-.. 
 K Vcrfl<'al niovciiK-nt of stationary coinlyh-. 
 L \'crtl<"il iiiovcnicrit of advaiK-ing condyle. In llic 
 Inclnrjr liioveiiicntH in extreme lateral occlusion. 
 
 'Mtcr a diagi'am of molar and 
 
 127 
 
PEOPEE FOEMATIOI^r OF CUSPID EDGES. 
 
 It may seem a little late to refer here to the formation of the edges 
 of the cuspids, since from some points of view they should have been 
 discussed in Part 11. But they are the most anterior teeth in which the 
 application of engineering principles effects important changes of form. 
 
 The upper and lower cuspids are probably the most difficult teeth 
 in either dentures or bridges to place in right relations. They are 
 wrongly placed in 99 cases out of 100 and neither dentist nor patient 
 is the wiser. But when they are rightly shaped and placed, the stabil 
 ity and efficiency of the dentures are so increased as to yield gratifying 
 results. 
 
 Properly formed artificial upper cuspids exhibit relatively long 
 mesial cutting facets and a shorter distal facet. Properly formed 
 artificial lower cuspids exhibit a short mesial cutting facet and a rela- 
 tively long distal facet. 
 
 The short facet on the mesial surface of the lower cuspid should 
 both occlude and articulate with a short distal facet on the cutting edge 
 of the upper lateral. A long facet on the mesial side of the upper cuspid 
 should both occlude and articulate with a long facet on the distal surface 
 of the lower cuspid. And the short facet on the distal surface of the 
 upper cuspid should articulate with the mesial facet on the buccal 
 cusp of the lower first bicuspid. In other words, the upper lateral and 
 cuspid should occlude with the lower cuspid when the jaw is in central 
 position, and during articulation these relations should continue un- 
 disturbed. Figure 76. 
 
 The purpose of these relations is to guide the anterior part of the 
 lower jaw during lateral movements, and to take up the shock when 
 the upper and lower jaws come into contact. For when the lower jaw is 
 moved downward, sideways and upward against the upper jaw in the 
 position of lateral occlusion, the jaws come into contact first and with 
 greatest force at the cuspids. And only as the jaw starts back to the 
 position of central occlusion do the bicuspids and molars come into pow- 
 erful contact. Hence the importance of correctly placed cuspids, to 
 either dentures or bridges. 
 
 This articulation of the cuspids serves another important purpose. 
 When food has been bitten from the mass by the incisors, it is started 
 toward the back of the mouth by the action of the tongue and cheeks. 
 When the jaws are separated, the action of the tongue and cheeks is to 
 place morsels lengthwise of the teeth. The cuspids coming into contact 
 before the other teeth, seize and hold the anterior ends of such morsels. 
 The molars, as they come into contact, hold the posterior ends, and thus 
 the fibres are held stretched while the bicuspids with their peculiar 
 open and shut articulation, come down upon them, to stretch and tear 
 them apart, and pierce between them. 
 
 The articulation of the cuspids will be more fully considered under 
 the subject of articulation. But it should be remembered that unless 
 the cutting edges have been properly formed, they cannot be properly 
 occluded or articulated and the discharge of their important functions 
 is rendered impossible. 
 
 128 
 
Fig. 77. 
 Proper relations of upper and lower cus- 
 pids in articulation. 
 
 CUSPID 
 
 RELATIONS ON/ 
 THE WORKING / r^j^ 
 SIDE IN LATERAL/ ^""^ 
 ARTICULATION 
 
 Q 
 
 -'■•t-t-t-*- 
 
 Fig. 79. 
 I'^icets on ujiper centrals, laterals and 
 ■tispids. 
 
 Fig. 7S. 
 How the faifts on artitici.-il upper cii> 
 pids must slniic. 
 
 129 
 
CEACKIisTG AND TEAEING POWER IN THE BICUSPIDS. 
 
 The human bicuspids are the lineal descendants of the bone crack- 
 ing teeth in meat eating animals like the dog, Figure 80, and are 
 given their special location in the denture that they ma)' crack all hard 
 and brittle foods and tear, stretch and separate all fibres. 
 
 In order that these teeth may crack all hard and brittle foods, it 
 is essential that the occlusal surface of each bicuspid shall be formed 
 into a grain trap for holding small seeds and grains, and that the two 
 adjoining bicuspids shall form traps for holding similar articles of food 
 too large for one tooth, as is shown in Figure 81. The occlusal sur- 
 face of a properly formed bicuspid will therefore present two small 
 traps like that diagrammatically illustrated in Figure 82 on the oppo- 
 site page. Only such a form as this will prevent the escape of small 
 grains as the upper and lower teeth come together. Such a formation is 
 shown in Figure 84. 
 
 The tearing action of the bicuspids on fibres is made possible by 
 the formation of the occlusal surfaces and the peculiar open and shut 
 form of articulation, which will be more fully considered later. The cus- 
 pids come into contact first during articulation, and the molars come into 
 contact before the lingual cusps of the bicuspids do, and hold fibres 
 firmly at both ends, while the bicuspids, with their open and shut ar- 
 ticulation, stretch the fibres, tear one from another, and pierce between 
 and separate them. This tearing action is diagrammatically illustrated 
 in Figure 85. 
 
 Trubyte bicuspids have been designed with a knowledge of these 
 functions and so shaped as to discharge them with the exercise of slight 
 force. So far as I know, they are the first bicuspids which have ever 
 been designed with any intelligent understanding of the functions they 
 must perform. 
 
 130 
 
Fig. SO. 
 Tbe bone craekini;- teeth of the d 
 
 Pig. 81. 
 Similar i-raeking action by human bi- 
 cuspids. 
 
 > •*!» i 
 
 X' 
 
 Fig. S3. 
 Lingual cusps open to receive seeds 
 and grains. 
 
 Fig. s-J. 
 Diagraniniatic representatidn (if a grain 
 trap. Samo trap in Trubyte bicnsjiids. 
 
 Fig. 84. 
 Ituccal cusps interdigltate in articulation. 
 
 Fig. S.-.. 
 Diagram of tearing action. 
 
 131 
 
CUTTING AND GEINDING POWER IN THE MOLARS. 
 
 The functions of the molars are to hold the posterior ends of 
 fibers which are being torn bj the bicuspids, to cut the torn fibers into 
 short pieces, and to roll fibers in such way as to isolate individual cells 
 and smash the cell walls to permit insalivation. The importance of 
 this smashing power is seen when it is understood that starches which 
 have not been insalivated are not digested. 
 
 Artificial molars are enabled to discharge these functions by a 
 smooth sliding articulation, which, in its form of greatest efficiency, 
 opposes a number of small, relatively sharp facets in such way that 
 they interact to produce the required effect. 
 
 The efficiency of the molars in cutting will be determined in no 
 small degree by the manner in which these facets interact. If they 
 merely press directly against each other, their efficiency will be small. 
 If they can be made to draw across each other, as one draws a knife in 
 cutting a substance, the efficiency will be greatly increased. The ideal 
 of cutting efficiency is diagrammatically shown in Figure 86 on the 
 opposite page. 
 
 The grinding power of the molars is dependent on the continued 
 opposition or contact of the facets during the time that the molars are 
 returning from lateral occlusion to central occlusion. Such opposition 
 or contact is made possible only by the application of engineering prin- 
 ciples to the formation of occlusal surfaces which will interact with 
 the necessary accuracy and efficiency. 
 
 The occlusal surfaces should exhibit deep fossae to permit the 
 escape of partly ground food from between the facets but not from 
 between the teeth. This leaves only fibers and unground cells between 
 the facets. 
 
 The sulci should be deep to permit easy escape of such portion of 
 the food as has been rendered fluid. 
 
 The dentist should not expect that the manufacturer can furnish 
 him porcelain teeth which are exactly designed for the conditions 
 peculiar to any given case or to his own methods of arrangement. Dif- 
 ferences in the kind of articulator used, in the manner of setting up, 
 in the lateral path, in the location of the rotation points and other 
 factors, will render slight modifications of the form of the teeth neces- 
 sary. The highest degree of efficiency in the dentures requires that 
 the dentist make these minute adjustments himself. 
 
 But the manufacturer can furnish teeth which are correct in 
 proportions, in shallowness of bite, in height of cusps and depth of foss?e 
 and sulci. Most important of all, he can furnish teeth with properly 
 interacting ridges and facets, so that the grinding of what may be called 
 the individual facets on the teeth shall be only their modification to the 
 peculiarities of the case in hand. 
 
 132 
 
Fig. 87. 
 Food cells are isolated and the cell walls 
 broken by the rubbing together of the 
 facets. The rubbing action is diagram- 
 niatically shown by the mortar and pestle 
 in which substances are pulverized. 
 
 Fig. SC. 
 Diagrammatic illustration of the cutting 
 action exhibited by oppo.sed ridges and 
 facets in Trubyte molars. If the point A 
 f>f the upper block be carried to the point 
 C of the lower block, and then the upper 
 block be so moved as to bring the point 
 B directly over the point D of the lower 
 block, each of the opposed ridges will cut 
 throughout its length with a drawing mo- 
 tion. This is the longest and most efficient 
 "cut" possible to these ridges. 
 
 Fig. 88. 
 Diagrammatic representation of the plan 
 on which artificial molars have generall.y 
 been Hha[)ed In the past. T'lii! f)road sur- 
 faces can not cut up foods to isolates the 
 cells, 'i'ticy can be appro.vimated only by 
 the e.verclse of great force. 
 
 Fig. 
 A. A cross section o 
 and second nudars sh 
 each tooth. 1'.. Kidgc 
 byte upper and lower 
 The cross sections sho 
 at the dotted line iu 
 
 mbyte 1 
 ng five 
 nd facet 
 dars opi 
 above w 
 s ligiire. 
 
 iwer tirst 
 ridges in 
 ■i in Tru- 
 losed. C. 
 ere made 
 
 133 
 
the impossibility of geinding improperly 
 
 formed teeth to proper bites or to 
 
 efficie:^[T forms. 
 
 If teeth are not given the correct depth of bite bv the manufacturer 
 and carved to efficient forms, it is practically impossible for the dentist 
 to grind them to advantageous bites, or to efficient forms of masticating 
 surface, as is made plain by Figure 90 on the opposite page. 
 
 Figure A shows the occlusal surfaces of upper and lower molars 
 ground to articulating form after the method formulated by Dr. 
 Bonwill. It will be noted that this method grinds a broadly con- 
 cave occlusal surface on each of the molars. Figure B shows 
 the same molars occluded. It will be noted that very broad opposing 
 planes are brought into contact, such as could be made efficient only 
 by the exercise of a force which neither bridges nor dentures can trans- 
 mit. The cracking and cutting formations which have been described 
 are entirely lacking, and no escapeways are provided for semi-fluid 
 food. 
 
 It is impracticable for the dentist to grind buccal cusps and grooves 
 which shall interact properly, and articulation is attained only by cusp 
 climbing cusp. The buccal cusp of the lower molar must climb the 
 long overhanging buccal cusp of the upper molar. This necessitates a 
 marked vertical movement even in the working bite. The bite of the 
 teeth is therefore deep, and dentures articulated after this manner are 
 easily displaced. 
 
 Figure C shows a longitudinal section of the same teeth. The 
 broad occlusal surfaces and the absence of cracking, tearing and cutting 
 formations are plainly seen. This is the only form to which improperly 
 formed teeth can be ground with a stone. Unfortunately there are still 
 dentists who use teeth thus ground. 
 
 Figure D shows the occlusal surfaces of the anatomical 
 moulds of The Dentists' Supply Company. These are carved to much 
 more nearly correct anatomical form than were the teeth of Dr. Bon- 
 will's time. The elevations of the cusps are more nearly correct, 
 and sulci and fossae are provided for the escape of food and for the 
 articulation of the cusps of one set with the grooves of the opposing set. 
 
 Figure E shows the molars occluded. The longitudinal groove 
 is entirely different in character than that shown in Figure B. The 
 upper lingual cusp and the lower buccal cusp no longer reach the bottom 
 of the fossse. Escapeways are provided for partly ground food and 
 buccal and lingual grooves, through which the opposing teeth move. 
 The upper buccal cusp does not overhang the lower molar as in Figure 
 B. The depth of bite in these teeth is only half as great as in those 
 shown in Figure B. 
 
 134 
 
Fig. 90. 
 
 Figure F shows a longitudiual section of the same teeth, 
 with the smaller opposed surfaces, the proper relations of cusps and 
 grooves, and the escapeways for food. These teeth were a great improve- 
 ment over the forms in Figure C. 
 
 Figure G shows the occlusal surfaces of Trubyte teeth, with 
 the formations for cracking, tearing and cutting which have been 
 described. 
 
 Figure H shows Trubyte first molars occluded. The character of 
 the longitudinal main groove and of the cusps, has been entirely changed 
 by making the cuspal inclines which form that groove, convex, in l)oth 
 the upper and lower teeth. The convex surfaces of the several cusps 
 prevent the opposing cusps reaching the deepest parts of the fosssp, and 
 provide large escape ways for partly crushed food. The upper buccal 
 cusp overhangs to only half the vertical depth of the buccal cusp in the 
 anatomical moulds and one-quarter the depth of the same cusp ground 
 after Dr. BonwilFs plan. The bite is proportionately less deep and 
 dentures made with these teeth are less easily dislodged. 
 
 Figure I shows a longitudinal section of these teeth. Instead of 
 presenting the flat opposed surfaces, shown in Figure C, or the single 
 convex surfaces shown in Figure F, these teeth exhibit from two to five 
 grooves, and from three to six cusps each. The cusps and cuspal ridges 
 are accurately opposed to grooves in the other set. 
 
 The grooves present escapeways for fluids or semi-fluid food, and 
 wlien the articulated teeth have been rubbed together with glycerine and 
 car])orundum to form tiny, sharp edged facets on each of these cuspal 
 ridges, the tearing, cutting and grinding powers are the greatest possil)le 
 to j)f)rcelain teeth. 
 
 135 
 
PART V. 
 
 The 
 Selection Of An Articulator 
 
FOREWORD. 
 
 The articulation of the adult natural teeth probably determines 
 the formation of the articulating surfaces in the condyles and fossae, 
 the muscular actions, and the habitual masticating movements of the 
 jaw. The arrangement of the artificial teeth will determine whether 
 the patient shall be enabled to continue those movements, which are the 
 most efficient he will ever have, or whether these movements shall be 
 destroyed, with a strong probability that other efficient movements 
 cannot be substituted. 
 
 Teeth are articulated when they are arranged to maintain grinding 
 and balancing relations with the masticating movements peculiar to 
 the patient for whom they are intended. If the work is intelligently 
 done, the patient is enabled to continue the habitual masticating move- 
 ments. The use of the dentures or bridges is learned with comparative 
 ease. The patient is given the greatest possible masticating power, and 
 food may be properly prepared for digestion. 
 
 Teeth are occluded when they are arranged merely for the opening 
 and closing movement. Occluded dentures generallj^ destroy the effi- 
 cient masticating movements habitual to the patient, and finally destroy 
 the formation of the articulating surfaces which were essential to the 
 continuance of those movements. They rarely, if ever, substitute efficient 
 masticating movements. And it is common history for patients with 
 occluded dentures to lose all definite control of the jaw movements. 
 It is difficult for patients to learn to use such dentures, and the fact 
 that some do finally learn is rather a tribute to the marvellous adaptive 
 power of the human frame than to the dentist's skill. The average 
 masticating power of occluded dentures is slight. 
 
 The dentist practically determines what quality of service he will 
 render liis patients when he selects an articulator, because the limita- 
 tions of the appliance become his limitations. The selection of the 
 articulator is therefore very important. 
 
 ]My owTi belief is that in every case where the patient can be brought 
 to see the benefits of superior service and to pay a fee which permits 
 such service, the dentist should determine and reproduce the movements 
 of the patient's jaw and arrange the teeth to harmonize with those 
 movements. 
 
 I believe also that it costs the dentist little, if any more, to articulate 
 the teeth so that they will be satisfactory from the beginning, than to 
 grind and fit and remake occluded dentures in the effort ''to make 
 them do." 
 
 In cases where such service is not possiljle, the dentist should 
 arrange the teeth in harmony with average masticating movements, 
 especially since this takes Ijut little more time tlian to merely occlude 
 them. 
 
 I liave endeavored to set forth in this section the reasons why 
 articulators which meet certain requirements (do not confuse that with 
 certain articulators^ should be used. 
 
 139 
 
SELECTIXG AX ARTICULATOR 
 
 It seems to me that an articulator cannot be intelligently selected 
 witliont at least an elementary knowledge of the normal jaw movements 
 in biting and mastication, a knowledge of some of the changes effected 
 in those movements bv the irregular loss of the natural teeth, and a 
 knowledge of the limitations of the articulator itself. 
 
 An articulator is a mechanical device in which artihcial teeth 
 niav be arranged to articulate in the mouth. In order that teeth mav 
 be articulated, it must reproduce the masticating movements of the jaw 
 with at least reasonable accuracy. If it is capable of only the opening 
 and closing movements, it cannot reproduce the movements of articula- 
 tion, and is therefore merely an occluding frame. 
 
 It is not necessary that an articulator should resemble in form the 
 human jaw, as some have thought, or that it be mounted with the upper 
 artiticial jaw fixed and the lower movable, as others have held. If it 
 reproduces with reasonable accuracy the more important jaw move- 
 ments, it makes little difference how unlike the jaw in appearance it 
 may be. 
 
 The first important step for him who would select an articulator 
 intelligently, is to know what are the more important jaw movements 
 to which the teeth will be sul)jected when they are placed in the mouth. 
 The jaw movements in order of importance from least to greatest are the 
 straight opening and closing, the incising and the lateral movements of 
 mastication. 
 
 I l)elieve that the character of these movements has been exhaust- 
 ively known for less than 10 years. At least the facts which have been 
 learned within that period have greatly extended our knowledge and 
 have permitted the construction of articulators which reproduce the 
 movements with greater accuracy than those of earlier days. 
 
 The present knowledge of these movements is the result of the 
 labors of many workers. Without disparaging the labors of any others, 
 T wish to call especial attention to the lal)ors of two men, Mr. Xorman 
 G. Jjennctt and J'rof. Dr. (jlysi, since they establish two points of the 
 utmost importance, as follows : 
 
 1. An articulator in whicli the upper jaw hinges or rotates on 
 the condyles cannot properly reproduce the average opening or lateral 
 movements. 
 
 2. An articulator which is to accurately reproduce the movements 
 peculiar to any given patient, must have rotation ])oints wliich are 
 movable at least in certain directions. 
 
 Such conclusions could be i-eached only after acciii'at(!ly recording 
 the movements of many jaws. It will be woi-th while, therefore, to 
 see how such movements were accurately recorded. 
 
 141 
 
HOW THE JAW MOVEMENTS WERE RECORDED. 
 
 Mr. Bennett recorded the movements of the several parts of the 
 jaw by projecting the illumination of lights fixed over those points on 
 the walls and ceiling. By an elaborate mathematical demonstration, he 
 showed that the recorded movements could not be reproduced with the 
 condyles as centers, but that the different movements had many centers 
 in different locations. So wide apart were some of the locations that he 
 doubted whether a practicable articulator could take cognizance of 
 them. 
 
 Prof. Gysi and his assistants gave almost two weeks of continuous 
 labor to confirming the discoveries by Mr. Bennett, and to devising 
 methods whereby jaw movements could be more easily recorded. Prof. 
 Gysi has lost some of the posterior teeth on either side of his lower jaw. 
 He made a partial plate which fitted the spaces, and which could be 
 clamped firmly in place by means of bands around teeth adjoining the 
 spaces. Stiff wires from both sides of this plate were brought to the 
 median line of the mouth where they passed out between the lips. 
 These wires were continued in to three ends, one of which was opposite 
 the head of each condyle and one opposite the symphysis of the chin. 
 Each of the three ends was fitted to receive a tiny lead pencil. A hori- 
 zontal plane representing the occlusal plane was affixed to the wires 
 to facilitate more accurate record taking. The whole appliance was 
 stable in position and made all the movements the jaw made. The 
 locations of the pencils and occlusal plane are shown in Figure ^o. 91. 
 
 RECORDING OPENING AND CLOSING MOVEMENTS. 
 
 To record the movements of the condyles and chin in straight open- 
 ing and closing, a frame like that shown in Fig. No. 92 was held 
 immovably against the head, and the pencils recorded upon it as the 
 jaw moved. The pencil and arm on the right side have been removed, 
 to permit a better view of the path, but their location is shown by dotted 
 lines. The chin pencil and its path are shown. The points in both 
 paths numbered from 1 to 5 inclusive are known as "stations" and 
 indicate that when the pencil recording the condyle path was arrested at 
 any given point, the pencil recording the chin path was located at the 
 point of like number, as at station 3 in both paths. 
 
 It will be noticed that the chin path describes a loop. This is 
 because this pencil regularly took one path in the opening movement 
 and another in the closing movement. 
 
 The importance of these records and their meaning will be de- 
 scribed after the method of recording the movements in the horizontal 
 plane has been described. 
 
 142 
 
Fig. 91. 
 
 KiK. '.IJ 
 
 143 
 
THE IMPOKTANCE OF THE RECORDS OF THE OPEl^IXG 
 AKD CLOSING MOVEMENTS. 
 
 They establish the fact that these movements cannot be reproduced 
 with the condyles as the centers of movement. 
 
 Only the portion of the condyle path numbered 1-2 is employed 
 while the teeth are in articulation, and the teeth pass out of contact 
 when the condyle reaches station 3. 
 
 Records of condyle and chin movements made in the manner 
 described on page 142 were transferred to flat sheets, and a common 
 center for portions 1-2 of the condyle path and portions 1-2 of the chin 
 path was located by erecting right angles from each path and prolonging 
 them until they met, as in Figure No. 93. 
 
 This center is located vertically about half way between the level 
 of the occlusal plane and the heads of the condyles, and a little back 
 of the condyle. Patients occasionally present with the rotation points 
 on the level of the condyles or the occlusal plane, but they are greatly 
 in the minority. 
 
 The mechanical accuracy of such a location can be easily seen by 
 tracing on paper the outlines of Figs. Nos. 94 and 95 and perform- 
 ing a simple experiment. 
 
 Fig. No. 94 shows the outline of a mandible with the correct 
 average paths of the condyles and incisors. Fig. 95 shows an out- 
 line of a similar mandible, with the points A-B-C as possible rotation 
 points. A is the rotation point common to all articulators where the 
 condyles are the centers of motion. C is located on the level of the 
 occlusal plane. B is the point determined upon by erecting perpendicu- 
 lars on the portions 1-2 of the condyle and chin paths in Fig. 93. 
 
 If Fig. No. 93 be superimposed on Fig. No. 94 and if a pin 
 be thrust successively through the points A-B-C and the mandible be 
 moved vertically across the outline from Fig. 94, it can be seen that 
 when the pin is at the point A there are no correct opening and closing 
 movements of the condyles. The lower incisors move through the path 
 A-2, which is inclined too far forward as it goes upward and too far 
 backward as it goes downward. The molars move very much too far 
 forward and backward in like manner. 
 
 When the pin is at C, the condyle describes the movement indicated 
 by the dotted line in Fig. 95. This is unlike the movement of the 
 condyle in opening and closing. The incisors move through the line 
 C-c, which inclines too far forward as it descends and too far backward 
 as it goes upward. The molars move in like manner and on a shorter 
 curve. 
 
 With the pin at B, the condyle follows very closely along the con- 
 dyle path in Fig. 94, while the incisors move through the path B-b, 
 which reproduces portion 1-2 of the incisor path. The molars move in 
 like manner. It is evident, therefore, that if an articulator is to cor- 
 rectly reproduce opening and closing movements, the rotation points 
 must be in the vicinity of the point B. 
 
 144 
 
Fig. 93 
 
 Fig. 94. 
 
 Fit:. 9.1 
 145 
 
THE PKACTICAL IMPOKTANCE OF CORRECT OPEIsTIKG 
 A1«[D CLOSING MOVEMEI^TS. 
 
 Wlien the rotation points of the articulator are in correct vertical 
 locations, it is not quite so essential that the models be mounted on the 
 articulator with the distance from condyles to incisors exactly like the 
 corresponding distance in the mouth. The bite may be raised or 
 lowered at will, either by design or accident, without deranging the 
 articulation of the teeth. 
 
 Both of these points are of great importance. If it be noted how 
 much too far forward and back the molar path "A" passes, in Fig. 
 No. 95, page 145, it can be seen that if the models be mounted too 
 near the condyles and the rotation point of the articulator be in the 
 location of ''A" or "C", in the same figure, the teeth will rapidly pass 
 into wrong relations if the bite be raised or lowered. 
 
 The effect of raising the bite when the rotation point of the 
 articulator is in the condyles, is diagrammatically illustrated in Fig. 
 No. 96. When the teeth are placed in the mouth where, in all proba- 
 bility the rotation points are not in the condyles, the molars come into 
 contact before the anterior teeth. Such contact either thrusts the lower 
 denture forward or displaces the upper. 
 
 Exactly the opposite result occurs if the rotation point of the 
 articulator is on the level of the occlusal plane and the bite is raised. 
 The front teeth then come into contact before the posteriors. 
 
 Such forms of wrong contact have been very common in the past 
 because dentists could not determine the source of the trouble. They 
 are very difficult to correct by grinding the teeth, and teeth so ground 
 lose all their power of efficient mastication. Moreover, such dentures 
 require repeated grindings to keep them even comfortable. 
 
 When the rotation points of the articulator are located at about 
 the point "B," the bite may be raised or lowered as desired without 
 deranging the articulation when the teeth are put into the mouth. In 
 one test case, the bite was closed the full length of the upper centrals 
 without any bad effects. 
 
 It is often advantageous to be able to arrange the teeth for a 
 slightly higher bite than the patient recorded, either that the cheek 
 tissues may be stretched and wrinkles taken out, or for esthetic purposes. 
 It is sometimes desirable to set the teeth a little high and close them 
 down to just the desired position when they are tried in the mouth. 
 
 The height of the bite is often changed without intention. 
 
 Fig. No. 97 shows that if the rotation point of the articulator 
 is at the location "B," the lower teeth move through such lines that 
 the cusps of one set will articulate with the grooves of the other set, no 
 matter how far the movement may be carried. 
 
 146 
 
Fig. 90. 
 
 Schematic illustration of the effect of raising the bite in an articulator having the 
 rotation points in the condyles "A." 
 
 On close examination it is seen that the distal slopes of the lower cusps come in 
 contact with the mesial slopes of the upper cusps long before the other slopes antagonize. 
 The molars strike before the bicuspids do. This is not articulation, and these teeth 
 cannot be ground to anything more than the crudest form of articulation. 
 
 Fig. t'7. 
 
 Scheniati',- illustration of tlie opposition of teeth with "B" as rotation point. The 
 condyle moves through its normal path. The cusps f>f the lower teeth move through 
 lines which bring them into' proper relations, when the bite is raised or lowered. 
 
 147 
 
KECOKDING LATERAL MOVEMENTS OF CONDYLES AND 
 
 CHIN. 
 
 For the purpose of recording the movements of the condyles during 
 lateral movements of the jaw, the points of the pencils opposite the 
 condyle heads were turned upward, and caused to register on a frame 
 supporting pieces of ground glass, as shown in Fig. No. 98. The 
 pencil at the symphysis was turned with the Sagittal plane, and recorded 
 on a card held at right angles with that plane. 
 
 The records of the pencils opposite the condyles showed that the 
 condyles have movements which were practically unknown and which 
 had not been incorporated into articulators. The condyle on the "work- 
 ing side" moved out of the fossa, away from the median line, while the 
 advancing condyle moved strongly inward. Measurements of the move- 
 ments of other jaws showed that these records differed in degree but 
 not in character. 
 
 It is not unnatural that these movements should be present, as is 
 seen when the bony formation of the glenoid fossae and condyles is 
 examined. The articulating surfaces of the fossae face inward, some- 
 times very strongly, as is shown in Fig. No. 99. The portions of the 
 condyles engaged in articulation during the lateral movements of the 
 j aw, faces inward in the same degree. It is natural that condyles which 
 face inward and which articulate with surfaces that face inward, should 
 move inward as they move forward. The records of a large number 
 of cases show that the advancing condyle moves inward at an average 
 inclination of 16 degrees with the Sagittal plane. This is a much 
 stronger inward movement than would be exhibited by an arc of a circle 
 with the other condyle as a center. 
 
 The records of the pencil at the symphysis were portions of curves. 
 They revealed one very important point which will be more fully con- 
 sidered later, namely, that they were not arcs of circles of which the 
 condyles were the centers. 
 
 148 
 
Fig. 98. 
 
 Vig. <M. 
 
 149 
 
THE IMPOKTANCE OF THE RECOKDS OF THE LATERAL 
 
 MOVEMENTS. 
 
 The records of the lateral movements seem to me more important 
 than the records of the opening and closing movements, because the 
 lateral movements are more numerous than the incising movements, and 
 because these are the movements which usually dislodge dentures which 
 have been merely occluded. 
 
 The records show that the condyles are rarely if ever the centers 
 from which the movements have been produced, and that they cannot be 
 reproduced by articulators having the rotation points in the condyles. 
 
 These records show also that the location of the rotation points, as 
 to distance outward from the median line, differs greatly in different 
 mouths, and sometimes on different sides of the same mouth. It appears 
 that when the teeth are lost irregularly, the horizontal location of the 
 rotation point changes to accommodate changed movements in nuisii- 
 cation. Sometimes the rotation points are between the condyles and 
 the median line, in which case they are said to be ''inside the condyles." 
 Sometimes they are farther from the median line than the condyles, in 
 which case they are said to be ''outside the condyles." 
 
 These records help us to understand why we have failed in articu- 
 lating many dentures to which we have given our best efforts. If we had 
 been able to record the jaw movements in such cases, we should doubt- 
 less have found the rotation point on one side of the head "inside the 
 condjde," and the rotation point on the other side "outside the condyle," 
 and that the articulator on which we arranged the teeth could not be 
 adjusted to such locations, and could not correctly reproduce the jaw 
 movements. 
 
 Figs. jSTos. 100 and 101 illustrate the movements of two extreme 
 cases. The horizontal location of the rotation points is determined by 
 the same method employed to determine the vertical location, that is 
 by erecting perpendiculars on the recorded lateral paths of the condyles 
 and incisor point. The locations are marked Ro. R. and Ro. L. 
 
 Fig. 102 illustrates the movements in a case where the position of 
 the right condyle is identical with that in Fig. 101 and the position 
 of the left condyle is identical with that in Fig. 100. The great 
 difference in the movements on the opposite sides of this mouth shows 
 very clearly the importance of locating with at least approximate 
 accuracy the positions of the condyles. 
 
 150 
 
Fig-. 100 
 
THE PRACTICAL VALUE OF THE LATERAL MOVEMENTS. 
 
 They reduce the steepness of the downward path of the condyle as 
 we have been accustomed to record it on articulators, so that the com- 
 pensating and lateral curves of the dentures need not be so steep as 
 when no lateral movements are present. 
 
 They permit articulation with much shallower bites in the molars 
 than would be necessary were no lateral moA'ements present. 
 
 They change the articulation of the posteriors. 
 
 They often permit the lower anteriors to be set to deeper under- 
 bite without being set back too far. 
 
 In most cases they greatly increase the cutting power of the incisors. 
 
 It is not uncommon for condyles to register a downward move- 
 ment of 60 degrees or 90 degrees to the occlusal plane, when the lower 
 jaw is thrust forward in the incising bite. When the combined down- 
 ward and lateral movements are recorded, the downward inclina- 
 tion is rarely more than 50 degrees, and two-thirds of all movements 
 seem to fall between 30 degrees and 40 degrees in inclination. 
 
 The more slightly inclined paths make it possible to set the den- 
 tures with flatter compensating and lateral curves. Dentures with flat 
 curves are easier for the dentist to articulate and are less likely to be 
 dislodged during jaw movements than those with steep curves. 
 
 In Fig. 103, Prof. Gysi has charted the required depth of bite 
 in first molars with different degrees of inclination of the lateral path. 
 The articulator was set with the condyles 12.5 centimeters apart, the 
 rotation point 10 centimeters apart, and the incisor guide incline at 
 40 degrees. The inclination of the downward path of the condyle was 
 at first fixed at 20 degrees, then at 30 degrees and lastly at 40 de- 
 grees. The lateral path was at first given no inclination and the 
 advancing condyle described merely the arc of a circle about the rota- 
 tion point of the opposite side. Later, it was given inclinations of 
 10 degrees, 20 degrees and 30 degrees. 
 
 By reading directly down the column of illustrations under the 
 heading "Con. 20 degrees," it will be seen that the depth of bite in the 
 molars, which is graphically represented by the figures 40 degrees, 125 
 degrees, 15 degrees when there is no definite lateral condyle movement, 
 grows less steep as the lateral inclination of the condyle path increases, 
 so that when the lateral path inclines inward 30 degrees, as it does in 
 some cases, the depth of bite is represented by the figures 18 degrees, 
 157 degrees, 5 degrees. The vertical lift of these latter teeth in articu- 
 lation would.be very much less than that of the former. 
 
 If the columns under the headings "Con. 30 degrees" and "Con. 
 40 degrees" be studied in the same way, it will be seen that a similar 
 flattening of the bite occurs as the inward inclination of the condyle 
 path becomes more pronounced. 
 
 152 
 
FIRST MOLAR 
 COND.12.5 cm. ROT. FTS. lOCm. INCISOR INCLUDE 40* 
 
 -_^ 
 
 Fig. 103. 
 
 FIRST MOLAR 
 
 ROT. PTS.IOCTTl. INCISOR INCLINE 40° 
 
 Fig. 104. 
 
 FIRST MOLAR 
 A0V.CONO.30MNW. LAT. INC. 10" INCISOR INC.40* 
 
 ROT. POINTS 5Cm. ROT. POINTS 14 cm. 
 
 
 -po: 
 
 Fig. 100. 
 
 A 
 
 BALANCING 
 BITE 
 
 Fig. 105, 
 
 Fig. ]07. 
 
 153 
 
If the depth of bite required by articulators in which the advancing 
 condyle moves only through the arc of a circle about the other condyle 
 is represented by the upper figures in the three rows here shown, and 
 the depth of bite required by an articulator with properly located rota- 
 tion points and properly inclined lateral paths is represented by the 
 depth shown in the three figures in which the lateral path is inclined 
 at 20 degrees, it appears evident that properly formed teeth can be 
 much better articulated in an articulator with properly inclined lateral 
 paths. It is evident also that dentures with such teeth, thus arranged 
 will be more stable in the mouth during mastication than teeth shaped 
 without reference to the lateral paths or arranged in articulators which 
 make no provision for lateral movements. 
 
 If, now, the diagrams in Fig. 'No. 103 be read across from left 
 to right, the relatively slight influence of the downward path on the 
 depth of bite in bicuspids and molars will be made plain. 
 
 When there is no definite lateral movement, the change of the 
 inclination of the downward path from 20 degrees to 40 degrees, 
 changes the depth of the working bite only 1 degree, from 15 degrees 
 when the downward path is at 20 degrees, to 14 degrees when the 
 downward path is at 40 degrees. When the lateral path is at 10 de- 
 grees, the change of the downward path from 20 degrees to 40 degrees, 
 effects no change whatever in the depth of bite. When the lateral 
 movement is at 20 degrees, the change of the downward path from 20 
 degrees to 40 degrees changes the depth of working bite only 1 degree. 
 When the lateral path is at 80 degrees, the change of the downward 
 path from 20 degrees to 40 degrees, effects no change whatever in the 
 depth of working bite. 
 
 These figures seem to me to indicate that the lateral path of the 
 condyles exerts more eft'ect on the articulation of the bicuspids and 
 molars than does the downward path. It is partly for this reason that 
 I regard the lateral path as more important in an articulator than the 
 downward path. 
 
 Fig. 104 shows the depth of bite required when the advancing 
 condyle of an articulator moves straight forward without describing 
 even an arc of a circle. The rotation points were fixed 10 centimeters 
 apart, and the incisor guide incline at 40 degrees. In the columns of 
 diagrams on the left, the condyles were fixed 15.5 centimeters apart. 
 In the column on the right, the condyles were fixed 12.5 centimeters 
 apart. 
 
 The diagrams show that when the downward condyle path is in- 
 clined 20 degrees, the depth of the working bite is 18 degrees, as 
 against 8 degrees when the path of the combined downward and in- 
 ward condyle movements register 20 degrees. When the advancing 
 condyle moves straight forward at a downward inclination of 40 de- 
 grees, the depth of the working bite is 20 degrees, as compared with 
 5 degrees, 7 degrees, or 10 degrees, when the combined downward 
 and inward movement registers 40 degrees. This is another evidence 
 of the influence of the lateral path of the condyle on the depth of bite. 
 
 154 
 
Fisr. lOS 
 
 The dentures here shown are ilhistrations of the difficulties often 
 encountered in articulating teeth without adequate records. 
 
 A dentist of no mean skill made for the patient full upper and 
 lower dentures using the articulator which had been most highly re- 
 garded up to the time of the discovery of the rotation points and lateral 
 paths. By painstaking care he had secured excellent articulation of the 
 dentures on the left side of the mouth, but had been unable to articulate 
 the teeth on the right side to be efficient in mastication, though they 
 balanced the dentures pretty well. Efforts to arrange the teeth in the 
 mouth had been unsuccessful. 
 
 When the condyle paths were recorded by Prof. Gysi's methods, it 
 was found that the downward path differed as follows : on the two sides, 
 that the lateral paths of the condyle differed also, and that^ the lateral 
 patli of the incisor point was so different on the two sides of the mouth 
 as to require that one rotation point be located as far outward horizon- 
 tally, as the condyle, while the other was less than half as far outward 
 from the median line. 
 
 Here, then, was a mouth in which the movements of the two sides 
 differed in every important particular. It is not wonderful that teeth 
 could not be arranged for such conditions in an articulator which em- 
 ployed the condyles as fixed rotation points and in which the lateral 
 paths of the condyles and incisors could not l)e correctly reproduced. 
 
 When the movements peculiar to this nioufh had been reproduced 
 in an articulator, the teeth were arranged, and when tried. in for the 
 first time, articulated perfectly on both sides of the mouth. 
 
 155 
 
THE PRACTICAL VALUE OF THE LATERAL MOVEMENTS, 
 
 (Continued.) 
 
 These figures show that the downward path of the condyle has 
 relatively slight influence on the formation of the teeth and depth of 
 bite, for a difference of 20 degrees in the inclination of the straight 
 forward and downward movement changes the depth of the bite only 
 2 degrees. 
 
 Fig. 104 should be interesting to those dentists who have desired 
 articulators with the condyles adjustable for different distances from 
 the median line. The vertical column on the left shows records from 
 an articulator with the condyles set at a width of 15.5 centimeters, 
 while the column on the right shows similar records with the condyles 
 set 12.5 centimeters apart. It will be noticed that the difl'erence in 
 the distance of separation has made no change in the working bite, 
 and has only rendered the working bite slightly steeper for the more 
 widely separated condyles. It is quite possible that dentists who have 
 expressed wishes for articulators with adjustable condyles have in 
 reality desired articulators with adjustable rotation points. 
 
 Fig. 105 shows that considerable changes in depth of wo^'khig 
 bite result from wide differences in the horizontal positions of the 
 condyles. If the rotation points be close to the median line, only 5 centi- 
 meters apart, the working bite will have an inclination of only 3 de- 
 grees, when the downward path is inclined 30 degrees, the lateral 
 path 10 degrees, and the incisor path 40 degrees. If, however, the 
 rotation points be moved until they are 14 centimeters apart in the 
 same horizontal plane, the working bite will have a depth of 14 de- 
 grees, while the lingual cusps of the molars will have quite a different 
 buccal slope. The average distance between the rotation points is 10 
 centimeters. It is evident, therefore, that the horizontal distance be- 
 tween the rotation points is much more important than the horizontal 
 distance between the condyles. 
 
 The vertical inclination of the incisor path has more influence 
 on the forms of the teeth and the ease of articulation, than has the 
 downward movement of the condyle path. Fig. 106 shows the 
 forms of first molars necessary with different vertical inclinations of 
 the incisor path. The condyles were fixed at 12.5 centimeters apart, 
 the rotation points at 10 centimeters, the downward path of the con- 
 dyle at 30 degrees, and the lateral inclination of the advancing condyle 
 path at 15 degrees. In the upper diagram the incisor path inclines 
 vertically at 20 degrees. The depth of the working bite is 10 degrees 
 and the buccal incline of the upper lingual cusp is fixed at 20 degrees. 
 The inclination of the incisor path was then changed to 60 degrees, 
 which is approximately what it is in the natural teeth at the period 
 of greatest efficiency. The depth of the working bite is increased to 
 18 degrees and the inclination of the buccal incline of the upper 
 lingual cusp becomes much steeper. Prof. Gysi believes that an inclina- 
 tion of 40. degrees for the incisor incline is better in prosthetic work 
 than the steep inclination of that incline in the natural teeth. ^ 
 
 156 
 
Fig. 109. 
 
 These diagrams seem to show that the steepness of the vertical in- 
 clination of the incisor path has more inilnence on the depth of bite 
 in the incisors, bicnspids and first molars, than has the vertical inclina- 
 tion of the condyle path, bnt that the influence of the condyle path 
 govern.s the positions of the second molars. 
 
 Fig. No. 109 A shows at the bottom an incisor guide incline, 
 with a vertical inclination of 20 degrees to the occlusal plane. At the 
 top is a diagram of a downward condyle path inclined 45 degrees. Just 
 above the incisor guide is shown the position of the first molars re- 
 quired by these inclinations of incisor and condyle paths. The position 
 of the second molars is shown above that of the first molar. 
 
 Fig. No. 109B shows at the bottom an incisor guide incline with a 
 vertical inclination of 40 degrees, and aftop a diagram of a downward 
 condyle path inclined 20 degrees. The position of the first molars re- 
 quired l)y these inclinations is shown just above the incisor incline, and 
 the position of the second molars just above the first. 
 
 It will be noted that the incisor path which is vertically inclined 
 40 degrees has deepened the -working and balancing bites in the first 
 molar, as compared with those in Fig. A where the incisor path inclines 
 verticallv onlv lialf as much. It will be seen that in the second molars 
 the balancing bite is deeper in Fig. A, where the condyle path is more 
 stecplv inclined. t • 
 
 tho.se facts seem to bo evidence that the very steep inclinations of 
 the coiidvlo path frecpunitly obtained by means of the incising bite, 
 merely result in arranging dentures to very steep lateral and compen- 
 sating curves in the second molars, whereas the less steeply inclined 
 paths recorded by Dr. Gysi's methods, especially when aided by correct 
 incisor supports," result in the arrangement of dentures to flatter curves, 
 witli incroasofl stability. 
 
 157 
 
THE I^FLUEXCE OF THESE ADJUSTME^sTTS O:^ THE 
 MOVEMEA'TS OF THE BICUSPIDS A^D MOLAES. 
 
 The adjustments of tlie downward condyle path, the inward 
 lateral path, the vertical incisor path and the distance between the 
 rotation points affect the movements of the teeth, 107 A B C D. 
 
 In Fig. 107A, the effect on molar movements in balancing bite 
 of three locations of the rotation points in the same horizontal plane are 
 shown in the three lines marked "R.5 cm.," which indicates a separation 
 of 5 centimeters between the rotation points, the lines marked "10 cm.," 
 which indicates a separation of 10 centimeters, and the lines marked 
 "14 cm." which indicate a separation of 14 centimeters. 
 
 The influence of the several inclinations of the downward path 
 of the condyle is confined to the balancing bite, as is shown in Fig. 
 107B. The line marked "C20 degrees," indicates the movement of 
 the teeth when all the other adjustments are average and the advanc- 
 ing condyle path inclines downward 20 degrees. The line marked 
 "C 30 degrees" indicates the movements of the teeth when the other 
 adjustments are unchanged but the advancing condyle path inclines 
 downward 30 degrees. The inclination of the line marked "C 40 
 degrees" indicates the movements of the teeth when the adjustments 
 are as above except that the advancing condyle path inclines downward 
 40 degrees. It will be noticed that in the working bite the move- 
 ments of the teeth are identical in all three of these inclinations. 
 
 In Fig. 107C the influence of the lateral inclination of the 
 advancing condyle movement is shown. The line marked "L degrees" 
 is the path taken by the teeth when the downward path of the condyle 
 is inclined 33 degrees, the vertical incisor path 40 degrees, and the 
 advancing condyle moves forward only through the arc of a circle with 
 the other condyle as the center. The lines marked "L 30 degrees," 
 indicate the movements of the teeth when the other adjustments of the 
 articulator are as mentioned, but the rotation points are so adjusted that 
 the advancing condyle path inclines inward 30 degrees. 
 
 Fig. 107D shows two lower molar teeth with three lines drawn 
 to lingual and three to buccal. The anterior and posterior lines in each 
 group of three, indicate the extreme difference in direction and extent 
 of tooth movement as affected by the adjustments in Fios. 107 
 A-B-C. 
 
 The middle line in each group of three represents the medium 
 course between these extremes of movement. It is secured by a medium 
 adjustment of an articulator, so that the rotation points are 10 centi- 
 meters apart, the advancing condyle path inclines downward at about 
 33 degrees and inward at about 16 degrees, and tlie incisor path 
 inclines vertically at 40 degrees. 
 
 Prof. Grysi believes that such adjustments will meet the require- 
 ments of about two-thirds of all cases. 
 
 158 
 
PERMIT DEEPER UXDERBITE OF LOWER TXCISORS. 
 
 The lower incisors should generally be set far enough back of 
 the upper incisors so that thej are just out of contact with the uppers 
 when the jaw is at rest in central occlusion. The depth of underbite 
 to which they mav be set, when in this position, is determined hy the 
 degree in which they move forward across the upper incisors, as the 
 jaw moves laterally. The more strongly forward they move, the less 
 may be the depth of underbite. The more sideways they move, the 
 deeper may be the underbite. 
 
 The degree of forward movement of the incisors, in lateral move- 
 ments of the jaw, is determined by the horizontal location of the rota- 
 tion points. If the rotation points are located well inside the con- 
 dyles, the incisors will pass strongly sideways, and may be set to a 
 relatively deep underbite. If the rotation points are located at the 
 condyles, the movement will be rather strongly forward, and the lower 
 incisors can usually be set to only a very shallow underbite. If the 
 rotation points are outside the condyles, the underbite will l)e extremely 
 shallow. If one rotation point is inside the condyle and one outside, 
 the depth of underl)ite will vary on different sides of the median line. 
 
 The movements of the incisors which determine the depth of 
 underbite possible in these three conditions can be better understood 
 by a study of the incisor movements in Figs. 100, 101, 10:2. 
 
 The average locations of the rotation points are one centimeter 
 inside each condyle. That is, if the condyles are four inches apart, on 
 the average, the rotation points would be a little over three inches apart. 
 This position permits the articulator to reproduce the average lateral 
 inclination of the condyle paths and of the incisor path. With the 
 rotation points in this location, the lower incisors pass sideways and 
 forward in a path which permits setting them to a deeper underbite 
 than when the rotation points are as far from the median line as the 
 condyles. The artistic effect of the deeper underbite is pleasing, and 
 the more strongly inclined sideways path of the lower incisors seems 
 less likely to dislodge the dentures. 
 
 INCREASE THE CUTTIXG POWER OF THE IXCISORS. 
 
 The cutting power of the incisor teeth is determined not alone 
 by the forms of the teeth and the power of the jaw, but in no small 
 degree by the direction of the movement by which the lower incisors 
 cross the uppers. The more directly the lower incisors move across 
 the uppers, the less the cutting power. The more the lower incisors 
 move sideways in moving across the uppers, the greater the cutting 
 power. This is often important in artificial dentures, where patients 
 freqviently require the maximum cutting power possible. 
 
 The relative cutting powers of the straight forward movement 
 and the strong lateral movement are diagranimaticallv shown in b'igs. 
 Xos. 110-11-12-13. 
 
 159 
 
Fig. 110. 
 Upper and lower teeth set to only straight up and down movement may be diagram- 
 matically illnstrated by the two wedges here shown. It requires much force to push 
 them through the food, shown as F. 
 
 Fig. 111. 
 
 The sideways movement of the teeth may 
 be here diagrammatically represented by 
 two wedges and the food by the round body 
 between them. If the wedges are forced 
 vertically through, great pressure will be 
 required. 
 
 If the wedges be moved in the direction 
 shown by the arrows, very much less force 
 will be "required. The reason is that the 
 cutting form of the wedges is changed. 
 With this motion the form of the wedge 
 is not the triangle formed by the lines 
 A D E, but the much sharper triangle 
 which is drawn inside each triangle and 
 lettered A — A^ — A^ in the upper, and B — 
 B^ — B2 in the lower. 
 
 Fig. 112. 
 The dotted outlines reproduce the tri- 
 angles A— D— E and B— D— E, while the 
 solid outlines a — a^ — a^ and b — b^ — b^ repro- 
 duce the triangles A— A^^— A- and B— B^ — B^ 
 which were produced by the lateral move- 
 ment of the triangles in Figure No. 111. 
 The sharper triangles have about three 
 times the cutting power of the triangles 
 A— D— E and B— D— E. 
 
 Fig. 113. 
 The left lower incisor at "a" is in the position of articulation with the upper right 
 central. In cases with strong lateral inclination of the incisor path, it will return to 
 occlusion, at "b" by following the direction of the arrow. This path of return permits 
 a relatively deep underbite and great cutting poM'er. 
 
 160 
 
THE (;VSI ADAPTABLE ARTICULATOR. 
 Eigs. Xos. 114 and 115. 
 
 There niav lie several articulators wliicii enable the dentist to 
 record and reproduce the luovemeuts of the human mandible, but I 
 am familiar with only one — the Gysi Adaptable Articulator. 
 
 The recording instruments which accompany this articulator per- 
 mit the dentist to record the downward and lateral paths of the condyles 
 and the horizontal path of the incisor point. The glenoid fossa? of the 
 articulator are so arranged that the inward inclination of the lateral 
 path of the advancing condyle, and the downward path can both 
 be reproduced. By means of the pattern which is traced on the Horse- 
 shoe riate, the horizontal location uf the rotation points is easily deter- 
 mined. 
 
 'Ihis articiilainr ntfers a very important improvement over others 
 in an Incisor Gtiide Jncline on the lower nujdel bow and a pin attached 
 to the upper model bow which travels on the incline. This pin supports 
 the anteridr ])art of ihc upper model bow during lateral movements of 
 the mandible. This support is important to correct movements of the 
 iucisor point and. as shown on page 157, the vertical inclination of the 
 horizontal path of the incisors exercises a good deal of influence on the 
 positions of the teeth as far back as the first molar. 
 
 The vertical inclination of this path on the articulator is mtich 
 less than in the natural teeth, because, as Prof. Gysi has re})eatedly 
 pointed our, the construction of artificial dentures is an engineering 
 problem, and should be executed in that manner which seems to promise 
 the greatest degree of success under the working conditions. The In- 
 cisor (iuide Incline slopes vertically at an angle of 40 degrees to the 
 occlusal plane. Put the Jncisor Guide Pin moves diagonally across it, 
 and the actual vertical inclination of its path is only 23 degrees. 
 
 When the movements peculiar to the patient have been reproduced, 
 the teeth may be as easily arranged as on any other articulator. 
 
 I'he technic of using this articulator is not difficult after one under- 
 stands the succession of steps and how to perform them. I believe it a 
 conservative statement that this articulator demands not more than one 
 hour additional time in the beginning of a case and less time in the final 
 adaptation of a case than any other articulator with which I am familiar. 
 
 If one were to take 50 full denture cases and agree to make them 
 comfortable and efficient for the patients, I believe it could be done in 
 less time with this articulator than with even a ])lain line, because 
 teeth ai-ranged on this articulator rarely re(|uiic any cluiuges when 
 tried in the mouth. 
 
 'J'he service which this articulator makes possible to patients en- 
 titles the dentist to a higher fee than dentures made on other ;irl iculators 
 because they cost more in time and money and are of greater \alue. The 
 service is really cheaper to the patient at the advanced fee, because the 
 irnpi'oved comfort and efficiency of tlie dentui-es ai'c of" gi-eiiter worth 
 to the patient's health. 
 
 161 
 
Pig. 114. 
 The articulating frame without measuring instruuieuti^ 
 
 Fig. 115. 
 
 The parts of the Gysi Adaptable Articulator are as follows : 
 
 Nos. 1-2, upper and lower parts of articulator frame which carry the uuuer and lower 
 model bows. 
 
 Nos. lA and 2A, upper and lower model bows. 
 
 Nos. 3-3 Straight Incisor Guide Pin and Curved Incisor Guide Pin. The curved pla 
 is used only when mounting models or setting anteriors. 
 
 No. 3A Small pin for all set screws. 
 
 Nos. 4-4 Frame work of Condyle Path Register. 
 
 Nos. 4A-4A Pencil holders and pencils of Condyle Path Register. 
 
 Nos. 5-5 Lateral Path Register. 
 
 Nos. 6-6A Stand and gooseneck for holding Condyle Path Register and models. 
 
 No. 7 Horseshoe plate. 
 
 No. 8 Degree plate for measuring inclinations of paths. 
 
 No. 9 Incisor Path Register. 
 
 162 
 
THE GYSI SIMPLEX ARTlCl'LATOU. 
 Fig. Xo. 110. 
 
 Soon after Prof. Gysi had perfected the (ivsi Adaptable Articiihi- 
 tor aud its advantages became apparent, he was earnestly besonght by 
 many members of the dental profession to devise an articulator which 
 should embody the principles of the Adaptable, but which did not re- 
 quire measurements on the patient and adjustments according to those 
 measurements. 
 
 Prof. Gysi therefore perfected the Gysi Simplex, fixing the rela- 
 tions by the average inclinations of several hundred condyle and incisor 
 paths which he had recorded by means of the Adaptable Articulator. 
 
 He employed the same form of condyle and fossa, but tixed the in- 
 clination of the downward path at oo degrees and the lateral inclination 
 of the advancing condyle path at 10 degrees. The rotation points were 
 fixed half way between the heads of the condyles and the occlusal plane, 
 and ten centimeters apart. The same form of Incisor Guide Incline and 
 Incisor Guide Pin w^as employed. An Incisor Guide was placed on the 
 Incisor Guide Pin so that if the dentist did not wish to employ a face 
 bow for determining the relations of the models to the condyles, he could 
 fix them upon the basis of the four inch triangle suggested l)y Dr. 
 Eonwill. 
 
 I have now been familiar with this articulator for about two years 
 and I have no hestitation in saying that in my opinion no other simple 
 articulator approaches it in facilitating arrangement of the teeth in 
 harmony with correct mandibular movements. If the inclination of the 
 condyle paths and incisor paths and the horizontal location of the rota- 
 tion points are not to be determined for each patient by accurate methods, 
 it is better to employ the average of a large numl)er of locations and ii> 
 cl illations determined by correct methods, than to employ methods which 
 are inadequate or incorrect for determining tlu^n in the individual case. 
 
 Prof. Gysi is of the opinion that this articuhitor meets the require- 
 ments of about two-thirds of the cases as they present, tiiough of course 
 it does not indicate which are the unusual cases. 
 
 A clever .Kmcrican dentist has dex-ised a met bod which I l)elieve 
 lariicly increases the usefulness of tliis articulator. He sets the u])per 
 teetli first and waxes them firmly in ])osition. When lie sets tlie lower 
 teeth on the ridge, he places the pins of each lower tooth on a cone of 
 liard wax and then surrounds the tooth with a softer wax. After articu- 
 lating the teeth out of the mouth, he puts the upper and lower trial den- 
 tures, in wax, into the mouth and causes the patient to make gentle 
 lateral movements of t,he mandible with the iippei- and lower teeth in con- 
 tact. If this is carefully done, the lower teeth are rotated upon the 
 cones of hard wax by the action of the uppers until thv.y assume those 
 positions which are most harmf)nious with the ])ati(!nt's jaw movements. 
 He reports very satisfiictory results. 
 
 163 
 
INCISOR 
 GUIDE PIN 
 
 ANATOMICAL 
 GLENOID FOSSA 
 
 1^ 
 
 ANATOMICAL 
 CONDYLE 
 
 GUIDE INCLINE 
 
 Fig. 116. 
 
 The Gysi Simplex Articulator Open. 
 
 The Gysi Simplex Articulator open showing some of the improvements which are 
 important to all plate workers. The condyles are formed by upright steel pins working 
 in properly formed glenoid f.ossse which direct them downward at an inclination of 33 
 degrees and inward at an inclination of 16 degrees. The weight of the upper model bow 
 is carried on the Rotation Points, shown in Fig. No. 117. The Incisor Guide Incline 
 and Incisor Guide Pin secure for the anterior part of the upper model bow a more 
 accurate movement than can be had when this form of support is lacking. 
 
 164 
 
UPPER BOW 
 SET SCREWS 
 
 SPRING HOLDING 
 PARTS IN POSITION 
 
 Fig. 117. 
 
 Rear View Gysi Simplex Artiriilator. 
 
 The vertical location of tlie rotation points half wa.v between the heads of the 
 condyles and the level of the occlusal plane is here clearly shown. This location permits 
 the artificial mandible to perform correct openiii.c and closing movements, so that the 
 height of the bite may be altei-ed without deranging the articulation. 
 
 The horizontal locution of the rotation points, each one centimeter inside the condyle, 
 is shown. This location is important l)ecauso it permits the advancing condyle to 
 describe an inward lateral movement of 1(5 degrees, and the other condyle to move out of 
 the fossa in the way the natural condyle does. In other words, it permits the entire 
 mandible to shift to tlie side in close imitation of the shifting of the natural mandible. 
 
 This horizontal location of the rotation points also imparts to tlic incisor point 
 a more strongly lateral movement than occurs when the rotation points are at the 
 condyles. T'his location permits a deejier underbite of the lower anteriors and increases 
 the biting power of the teeth. 
 
 The Incisor Cuide is not shown in tliis illustration but is shown in Fig. 110. 
 
 165 
 
PART VI. 
 
 Mounting The Trial Plates 
 On The Articulator 
 
MEASURIXG THE PATIEXT\S .MAXDI lU-LAK .MOVEMENTS. 
 Fies. Xos. llS-llU-l-2()-l-21-l-2-2-l-2:]'l-2^. 
 
 '&" 
 
 If the Horseshoe Phite was applied to the lower trial plate and 
 the Hicisor Path Register was mounted on the upper trial plate in the 
 process of taking the bite, and the horizontal path of the incisor point of 
 the upper jaw was registered as described on page 43, the taking of the 
 other records of the patient's mandibular movements is very simple. 
 
 If the Horseshoe Plate was not attached to the lower trial plate at 
 that time, it should be now. Before putting it into position, the portion 
 of its occlusal surface anterior to the first indentation on each side is 
 blackened hy smoke from burning oil of cloves or vaseline on cotton, and 
 a thin him of wax is spread over the blackened area with a hot spatula 
 to make a place for a permanent record, or the plate may be coated with 
 wax mixed with lampl)l:ick. The lower surface of the Horseshoe Plate 
 is then pressed ujxiii the occlusal surface of the lower trial plate so that 
 the blackened area pi'ojects forward of the anterior margin of the lower 
 trial plate, and that the whole Horseshoe Plate is evenly placed on the 
 two sides of the median line of the trial plate, with the two bars project- 
 ing forward in that line, as shown in Eig. Xo. 118, Any elevations in 
 the upper trial plate caused by pressure of the Horseshoe Plate should 
 be trimmed away and a little vaseliuo rubbed on the Horseshoe Plate 
 to facilitate movements. 
 
 The Incisor Path Register is mounted on the labial surface of the 
 upper trial plate in such manner that the recording pin is over the 
 median line, and that when the pin is all the way down it will press on 
 the blackened area of the Horseshoe Plate, The position of this pin is 
 controlled by a spring and a handle, and when not in use it should be 
 lifted and turned so that the point does not rest on the Horseshoe Plate. 
 
 The heads of the condyles are located, either by feeling, or by 
 measuring one-hall' inch forward from the tragus of the ear, on a line 
 toward the outer corner of the eye. The location of the head of each 
 condyle is plainly marked on the face. 
 
 Place both trial plates in the mouth. 
 
 The Condyle Path Register is placed in position by mounting it on 
 the two bars projecting forward from the Horseshoe Plate as shown in 
 Fig. 110. 
 
 The pencil holders at the rear terminations of the Condyle Path 
 Register are turned so that the ends of the pencils which point vertically 
 are al)0ut one-half inch from the sides of the face and opposite the marks 
 locating the heads of the condyles. They are locked in those positions. 
 See Fig. 119, 
 
 The patient is retjuested to move the mandible fi'oni side to side, 
 keeping it in contact with the upper jaw. Some patients tind it difhcult 
 to do this, and it is often necessary to instruct ])atients l)v standing in 
 front of them and performing similar movements until they learn how. 
 Patients who have worn occluded or poorly articulated dentures for long 
 periods often lose all control of the jaw movements, and in some cases 
 
 169 
 
is is quite impossible to make records of deiinite movements. In such 
 cases the articulator should be set at average adjustments. 
 
 The frame supporting the glass or celluloid tabs and called the 
 Lateral Path Register, is held about the head in the manner shown in 
 Figs, ISTo. 119 and 120, and so that the tabs are in contact with the ends 
 of the vertical pencils. The frame is held at an inclination of about 
 40 degrees to the occlusal plane, and firmlj supported in position by 
 pressing the fingers on the sides of the head. It need not necessarily be 
 held exactly straight front and back. As the pencils move, it can be 
 noted whether the Register is so inclined that the pencils continue con- 
 tact with it, and it should be inclined until the pencils maintain contact 
 with it throughout the movement. 
 
 One lateral path may be recorded at a time, but it is then necessary 
 to hold the Register so that when the pencil records the second lateral 
 path, the pencil which recorded the first one is at the rear termination 
 of the path. The Register must be held in the same front and back axis 
 during the making of both records. 
 
 The dentist should not be discouraged if his first or second efforts 
 do not afford the character of records he desires. Some patients are in- 
 capable of making them for reasons explained above or because of defects 
 in the articulating mechanism. One patient who gave trouble in this 
 respect was found to have sustained an injury to the joint thirty years 
 before, which greatly limited its movement. There is also a slight 
 technic, as there is to every operation in dentistry, and the dentist will be 
 a much better master of it after one or two attempts. 
 
 When the records of the lateral paths of the condyles are sufficiently 
 clear, the Lateral Path Register is laid aside, and the points of the hori- 
 zontal pencils are placed opposite the heads of the condyles as in Figure 
 ISTo. 121. They should be firmly locked in this position since they are to 
 serve as- guides for mounting the models in correct positions on the 
 articulator. 
 
 When the pencils are in proper positions, a visiting card is placed 
 between one pencil and the side of the face so that its lower edge is 
 parallel with the broad plate supporting the pencil holder. This makes 
 the lower edge of the card parallel with the occlusal plane of the trial 
 plates. With the card in this position, the thumb screw controlling the 
 horizontal position of the broad plate is turned until the spring behind 
 the pencil is about half compressed by pressure of the pencil against the 
 card. The patient is then asked to make lateral movements of the man- 
 dible with the jaws in contact, or if this is not possible to make vertical 
 opening and closing movements. The card is held steady until three or 
 four movements have been made. Some patients record very uncertainly 
 at first, but after a few moments, settle into the record of a definite path. 
 In a few cases, the records are so indefinite as to have no value. In such 
 cases it is necessary to employ average adjustments. See Fig. No. 122. 
 
 (Continued on Page 1Y8.) 
 170 
 
FlK. 118. 
 'I'lic liKlsor I'iith Ucfjistcr niiil Horscslioo I'liitc in I'ositiim. 
 
 171 
 
Fig. 119. 
 
 Vertical pencils adjusted in position. 
 One method of holding steady. 
 
 Lateral Path Register approaching oosition. 
 
 172 
 
Fig. 120. 
 LiittTMl I'ath i:«-KistrT ill coiitnit wltli i»encils. .Aiiotlicr position for boldinir register 
 
 steady. 
 
 173 
 
Fig. 121. 
 Horizontal pencils in position and firmly locked. 
 
 174 
 
Fig. 122. 
 
 Ue<oi(liii« ttie Forward Tilth •>( tlii' ( •.iiidylc.*' 
 
 175 
 
Fig. 123. 
 Incisor Path Register recording horizontal path of incisor point. When the operator 
 is sufficiently skillful, this path may be recorded at the same time as the lateral path. 
 
 176 
 
FlK. 124. 
 An Incisor path Idealized for purijoses of illustration. 
 
 177 
 
MEASUEII^G THE PATIENT'S MAi^DIBULAR MOYE^rEXTS 
 
 (Contimied from Page 170.) 
 
 Wlieu the record of one condyle patli has been obtained in this man- 
 ner, the other end of the card is employed to register the other condyle 
 path in like manner. The card is laid aside with the Lateral Path Regis- 
 ter, for fntnre nse. It is important to mark the paths "right" and "left" 
 to avoid confusion later. 
 
 The Condyle Path Register is now removed from the Horseshoe 
 Plate and the pin of the Incisor Path Register is released so that it can 
 record upon the blackened area of the Horseshoe Plate. The patient is 
 caused to make lateral movements of the mandible, with the trial plates 
 in contact, and the pin will trace a record in the black wax. Sometimes 
 this record will be very indefinite ; at others its margins will be sharply 
 defined. Only a few intelligent movements are necessary. 
 
 If the Incisor Path Register was mounted high enough above the 
 Horseshoe Plate so that the pattern traced hj the pin can be watched, the 
 dentist may gain useful information. In ninety-nine cases out of a 
 hundred the pattern traced in the wax will have a round point as long as 
 the lower jaw is projected forward from its natural position of rest, and 
 a sharp point when the jaw is in a position of rest. This is very impor- 
 tant. 
 
 AYhen the pattern is satisfactory, or is as good as can be gotten, 
 the patient is allowed to rest a moment so that the point of the pin is 
 ih the point of the pattern it has traced. Marks are made vertically 
 across both trial plates indicating their relative positions, or better 
 still, staples are inserted into the buccal surfaces of both plates fasten- 
 ing them in correct positions. 
 
 The trial plates, with the Horseshoe Plate and Incisor Path Regis- 
 ter in place are then removed from the mouth. 
 
 178 
 
Fig. 1-25. 
 
 On the left, the lower trial plate with the Horseshoe Plate properly inouuted. 
 Ou the right, the upper trial plate which has been pressed dowu upon the Horseshoe 
 Plate aud built up in places and pressed down agaiu until the pressure is even all around. 
 It is important to have this pressure even. Before recording the condyle paths tlie festoons 
 made by the Horseshoe Plate must be trimmed away, leaving a plane surface. A little 
 vaseline is applied over the surface of the Horseshoe Plate. 
 
 Fig. 12(i. 
 Upper and lower trial plates jxisitioned by Incisor Cuidc I'in in ii.ittcrii on 
 Horseshoe Plate and marks on buccal surfaces. Correct vertical marks and incorrect 
 sloping niarlis shown. 
 
 179 
 
DETEPailKIlS^G THE IXCLIXATIOXS OF THE LATERAL 
 PATH OF THE COXDYLE. 
 
 Figs. Xos. 127-128. 
 
 If the lateral paths of the condyles were properly recorded, there 
 may be visible a spot, near the beginning of each path, where the line 
 seems to have started and from which it has gone a little backward and 
 then a much longer distance forward. This spot is visible only when 
 the rotation centers of the human jaw are "inside the condyles," a fact 
 which cannot be determined at this time. 
 
 If such a point is present on each lateral path, a straight line is 
 drawn from the point in one path to the similar point in the other path, 
 by aid of a ruler. This line serves as a base line for the calculations 
 that are to be made. 
 
 If no such point is present in either path, a ruler is laid touching 
 the beginnings of both lines, and a line drawn across each path like 
 the line A-B in Fig. Xo. 127. This is the base line. 
 
 The fact that the base line is drawn in this manner from the begin- 
 ning of one j)ath to the beginning of the other, makes it unnecessary to 
 hold the Lateral Path Register in any particular front and back line 
 about the head when recording these paths. 
 
 By means of any object presenting a right angle, such as a visiting 
 card, a perpendicular line is erected on the base line at the point where 
 it crosses each lateral path. The tracing of the lateral path is now pro- 
 longed hy laying a ruler along its central part and carrying the line 
 out to the end of the tab. The Degree Plate which accompanies the 
 Gysi Adaptable Articulator, is now laid with its degree side along the 
 perpendicular erected on the base line, and the line of the lateral path is 
 prolonged with any convenient object until it crosses the edge of the 
 Degree Plate. The inclination of the lateral path in degrees may then 
 be read off and recorded for future use. Such records should be made 
 in a permanent form as they are often found useful at future dates. 
 
 The inward inclination of the advancing condyle path may vary 
 from 2 degrees or 3 degrees in a few cases, to 30 degrees or more in a 
 few cases at the other extreme. The average inclination of a large 
 number of records is 16 degrees. 
 
 The stationary condyle often records a short but well defined path 
 which generally leads outward from the median line, and may be in- 
 clined either forward or backward. This path is of no known signifi- 
 cance except as a testimony that the centers of movement of the human 
 mandible are not in the condyles, but that lateral movements of the chin 
 are often or always accompanied by a shifting of both condyles, the 
 chin and all intervening points, to the same side as the chin. It is an 
 evidence of Prof. Gysi's wonderful power of analysis that in both the 
 Adaptable and Simplex Articulators, the artificial mandible can make 
 this form of lateral motion. 
 
 180 
 
Fig. 127. 
 
 Lateral condyle paths recorded and strengthened. A-B line drawn from "i-esting 
 point" in one path to "resting point" in the other, and perpendiculars erected at 
 these points. Angles may be measured with the Degree Plate used for measuring 
 forward paths. 
 
 L 17' 
 
 16' K 
 
 13° 
 
 10° 
 
 33" 
 
 IS" 
 
 ]no 
 
 1^ 
 
 lis" 
 
 w 
 
 is-^ 
 
 n<' 
 
 Zo^ 
 
 ZO' 
 
 3° 
 
 10° 
 
 10° 
 
 11° 
 
 16" 
 
 i^" 
 
 iZ" 
 
 r 
 
 Fig. lliS. 
 
 Six pairs of condyles have their inward lateral iiiovt-int-ntK re<<)r(led in tlic trarings. 
 Ten other pairs have their degrees of inward lateral movement recorded in the 
 central columns, but the tracings are not given. The average inward movement of these 
 16 pairs of condyles is 17 degrees for the left condyle and l(i degrees for the right. 
 
 181 
 
MEASUKDsTG THE IjSTCLIXATIOX OF THE DOW]NtWAKD 
 
 CONDYLE PATHS. 
 
 Figs. Xos. 129-130-131. 
 
 The downward paths of both condyles are recorded on the visiting- 
 card and each is marked with an initial showing its proper side of the 
 head. 
 
 A line is drawn along the center of each path, ignoring both ends 
 if they are mnch cnrved, and prolonged to the base line of the card. 
 The Degree Plate is laid with its degree side along the base line of the 
 card and its sharp angle at the point where the line through the condyle 
 path joins the edge of the card. The point where the line crosses the 
 degree measurements on the Degree Plate will indicate the number of 
 degrees that the path is inclined to the occlusal plane. 
 
 Both paths are measured in this way and the degrees of inclination 
 are noted by the initial indicating the side. As mentioned in Part 1, 
 all these factors should form part of a permanent record of each case. 
 
 adjusting the articulator to the condyle path 
 
 incli:ntatio]^s. 
 
 At the points marked "Lateral Path Set Screws" in Fig. jSTo. 114 
 will 1)6 found set screws wdiich govern the lateral inclination of the arti- 
 ficial glenoid fossse. If these screws are loosened, the plates forming 
 the roofs of the foss?e and marked ''Adaptable Lateral Path" may be 
 turned until the inward wall of the fossa has been inclined to the median 
 line the number of degrees indicated in the lateral paths, by means of 
 the figures on the upper surfaces of the plates. For lack of space for 
 numbers, the Fig. 1 on this plate stands for 10 degrees. Fig. 2 for 20 
 degrees, etc. These adjustments should be made for both sides and the 
 screws tightened. Care should be taken not to confuse the sides, since it 
 is very easy to mistake the left for the right unless the articulator is held 
 before one, with the incisor point forward. 
 
 At the points marked "Forward Path Set Screws," in Fig. No. 114: 
 will be found set screws which control the downward inclination of the 
 glenoid fossae. If the little pin which projects from the base of the 
 Incisor Guide Pin marked "Removable Pin For All Set Screws" be 
 taken from its sheath, it will be found to fit the hole pierced through 
 each of these screws, and by it the screws may be loosened. The plates 
 may be turned downward until the pointer is at the inclination indi- 
 cated by the records of the downward paths of the condyles on the plate 
 marked "Adaptable Downward Path." Care must be taken not to 
 confuse the sides, in cases where they are different. 
 
 The record of the horizontal path of the Incisor Point cannot be 
 used until the models are mounted on the articulator. It will then be 
 used to determine the horizontal positions of the Rotation Points. 
 
 182 
 
Fig. iL'll. 
 (From The Dental Cosmos, i 
 Analysis of right aud left condyle paths as secured by the method shown in Fig. 122, 
 C, Condyle path. L. Left. K, Right. Oc, Plane of occlusion. 35°, Angle of middle part 
 of path "to plane of occlusion, r, Resting position of condyle. R^. Path of condyle in a 
 right lateral movement. L^. The same in a left lateral movement, u. Forward bite or 
 wide opening and closing movement. 
 
 Fig. l^!0. 
 Lines drawn through the central portions of forward paths of condyles. 
 
 Fig. i:;i. 
 .\|.-a>uriiig two patlis similar to those shown in Figure No. loO. 
 
 183 
 
■■'it: 
 
 ttC: 
 
 25-: 
 
 kr 
 
 -•'31- 
 
 .37"- 
 
 
 >^ 
 
 2fi 
 
 ■^ 
 
 ii'' 
 
 m'\ 
 
 ■w 
 
 \ 
 
 '3d': 
 
 ■''2i'. 
 
 m 
 
 z-^ 
 
 33' 
 
 /33"-- 
 
 /- ^-^ 
 
 J?9» 
 
 
 (From The Dental Cosmos.) 
 Fig. Jso. 132. Typical Forward Condyle Paths. 
 
 The paths "a" to "i"' inclusive show differences in form and slant of the right and 
 Ifft paths in the same patient. 
 
 The paths "m" to "q" show that other differences in form or slant may occur between 
 the path of the opening movement and the path of the lateral movement of the mandible. 
 
 The path of the lateral movement alone has value in the articulation of artificial teeth. 
 
 184 
 
POURING THE .MODELS. 
 
 The material of which the models are made and the manner of 
 pouring may have a great deal to do with the lit of the dentures. 
 
 It is my custom to cause the rugae on the palatal surface of the 
 impression to be deepened by carving and to have the models poured 
 with Spence's plaster. I am indebted to Dr. Tench for the following 
 technic which we regularly employ and which yields as tine models as I 
 have ever seen. 
 
 The compound impression is given a thin coat of either sandarach 
 or shellac varnish. This is allowed to dry and is followed by a coating 
 of a water solution of silex (water glass). This also is allowed to dry. 
 
 Put from one to one and one-half ounces of water into a clean 
 plaster bowl and slowly add the plaster by sifting it from the blade 
 of a spatula, at the same time lightly jarring the bowl on the bench 
 to hasten saturation. Continue adding plaster until no free water 
 can be seen. Then spatulate the mass against the side of the bowl, 
 occasionally adding dry plaster till the mass becomes too stiff to work 
 easily. As it sets very slowly, no special haste is necessary. 
 
 Turn the contents of the plaster l)Owl out on a glass slab and spread 
 it into the form of a layer about 8-10 inches thick, by a quick tapping 
 motion of the spatula. This helps to eliminate air bubbles and im- 
 proves the mix. 
 
 Test the consistency of the mix by shaping some of it into a cone 
 and standing it on the slab. If it is as resistant as fairly thick putty 
 and retains its shape, it is ready for use. If it is too thin to retain its 
 form, sprinkle dry plaster over the mass and incorporate it by the same 
 tapping motion used for forming it into a slal». 
 
 If a smooth model is desired, this plaster should never be mixed 
 80 dry that the surface will not glaze when it is spread out and patted as 
 described. 
 
 Carry a strip of the material about Vi inch wide to the depression 
 formed by the alveolar ridge, and pack it, glazed side down, by a quick 
 tapping motion with the ball of the index finger, working from the 
 center of the strip toward the heel of the impression. When the material 
 is in place, jar the impression on the bench until the surface of the 
 I'laster glazes. Add another portion of plaster to that already in position 
 tj building it on, and patting and tapping in the same way. In this 
 way the palatine surface of the impression may be covered, working 
 from ridge to center. 
 
 The model should be l)uilt u}) until it is about 14 of an inch thick 
 at its thinnest place. The nuirgins of the model should be shaped to be 
 vertical while the material is soft, since it can be trinnned only with 
 difficulty after it has set. These margins should be flush with the 
 labial and buccal surfaces of the impression. 
 
 The ]ow(;r model is packed in the same manner except that a 
 bridrre of base plate wax is form(!d to cover the opening in the center 
 of tlie mouth occupied by the tongue. Plaster is built over this, in the 
 same manner as in the upper impression. The resulting model is 
 mucli stronger than it would be if the center were left open. 
 
 185 
 
THE RELATIOXS OF THE IXCISOR POIXT TO THE 
 
 COI^DYLES. 
 
 I believe it to be important to mount the trial plates so that the 
 incisor point is at the same distance from the artificial condyles that it is 
 from the natural condyles in the patient for whom the dentures are in- 
 tended. I believe it to be well also that the occlusal plane shall be at the 
 same distance below the level of the condyles as in that particular 
 patient. Both of these ends may be easily achieved. 
 
 It was shown on page 153 that the horizontal distance between the 
 condyles had little effect on the forms of the teeth or the depth of the 
 bite. It has less influence on the movements of the teeth, because the 
 condyles are not the centers of movement. But if the trial plates are 
 mounted at the right distance from the condyles, they must be at right 
 distances forward from the rotation points also. And that comes much 
 nearer the re-establishment of the mandibular triangle for that patient, 
 than the mounting of the trial j)lates by chance. The more nearly the 
 mandibular triangle is reproduced, the more nearly correct will be the 
 incisor movements of the trial plates, and the more comfortable and 
 efficient the dentures will be. The movements of the incisor points are, 
 as has l:)een explained, the most important of the denture movements, 
 because if they are correct, the movements of the other parts are nearly 
 sure to be right. 
 
 There is another important reason why the trial plates should be 
 mounted on the articulator in right relations to the condyles. It is that 
 the triangle formed by the two condyles and the incisor point, commonly 
 referred to as "Bonwiirs triangle," is rarely symmetrical; that is, it 
 is rarely four inches on a side. The incisor point is often so far to one 
 side of where Bonwill's measurements would bring it, that it may make 
 considerable difference as to whether or not it is correctly located. 
 
 The illustrations on the opposite page, from Dr. Frahm's article 
 in The Dental Cosmos of May 1914, illustrate not only the difference 
 in size of different human mandibles, but the fact that the triangles 
 erected on the bases of different human skulls are often not equilateral, 
 as Bonwill thought, and that the incisor point is often considerably at 
 one side of the point where Bonwill located it. 
 
 The trial plates may be mounted on the articulator so that the 
 incisor point is at the right distance forward of the condyles and the 
 occlusal plane is at the right distance below the condyles, and the in- 
 cisor point is in the horizontal position peculiar to that patient, by the 
 use of the Condyle Path Register accompanying the G-ysi Adaptable 
 Articulator, or the Snow Face Bow which may be used with the Gysi 
 Simplex Articulator. 
 
 186 
 
Fig. A. 
 Theoretical equilateral triangle. 
 
 -f-3 m.i 
 
 Fig. B. 
 
 Not four inches on a side and not 
 
 equilateral. 
 
 /<7/mn,- 
 
 Fig. C. Fig. D. 
 
 Incisor point at right of middle of base. Incisor point at left of middle of base. 
 
 Fig. K. 
 lucisor iioint at left of mi 
 
 111- of base. 
 
 Fig. F. 
 Far from ocjuilateral. 
 
 Fig. i:j:!. 
 
 I)r. I'rahm's drawings showing that the mandibular triangle is not equal sided and 
 that the incisr»r iioliit Is often not in tlie median line of the base. (From the Dental 
 ('osinos.^ 
 
 187 
 
MOUNTIA^G THE MODELS ON THE ADAPTABLE ARTICU- 
 LATOR. 
 
 Fig. No. 134. 
 
 When the models are ready for mounting, the Condyle Path Pegis- 
 ter is mounted on the Gooseneck and its holder, see Figs. Nos. 115 and 
 134, by fitting the hole in the front of the block on the Register over the 
 end of the Gooseneck. 
 
 The models are put into the trial plates and preferably fastened 
 there by the application of wax along the margins of the trial plates. 
 The tops of the models are soaked in water to facilitate attachment to 
 the model bows. If the trial plates were not fastened together in correct 
 relations, as described on page 178, they are now placed in right rela- 
 tions by locating the pin of the Incisor Path Register in the apex of 
 the pattern traced on the Horseshoe Plate, and bringing the marks 
 across the buccal surfaces of both trial plates into right relations. These 
 relations will be much more easily established if the marks have been 
 made vertically after the manner marked "good" in Fig. No. 12G. When 
 the trial plates are in right relations, they are fastened so by w^arming 
 the wax at their occlusal edges, or by putting staples into the buccal 
 surfaces or by passing a cord around both. 
 
 The Horseshoe Plate, with the trial plates and models attached, is 
 now mounted on the inside of the Condyle Path Register, by thrusting 
 the two projecting arms of the plate into the two holes in the block of 
 the Register. 
 
 The curved Incisor Guide Pin, (part 3, Fig. 115) is now placed in 
 the opening in the upper model bow, with the top of the pin flush with 
 the top of the opening. The Gooseneck, with its attachments is moved 
 until the ends of the horizontal pencils are opposite and equally distant 
 from the ends of the condyles. These vertical relations can be attained 
 by raising or depressing the Gooseneck in its holder. The plates sup- 
 porting the pencil holders must not be moved. 
 
 Plaster may be poured onto the upper model attaching it to the 
 upper bow in these relations, or the Gooseneck and attachments may be 
 moved away and plaster poured over the lower model bow and the Goose- 
 neck replaced so that the pencils are in right relations. If the 
 plaster is poured over the upper model first, it will be necessary to 
 invert the articulator and models w^hen the plaster is hard and attach 
 the lower model to its bow. If the lower model is moved into the 
 plaster on the lower bow, it is necessary only to pour plaster on the upper 
 model and let all harden. 
 
 DETERMINING THE HORIZONTAL LOCATIONS OF THE 
 
 ROTATION POINTS. 
 
 Fig. No. 135. 
 
 When the models are firmly attached to the model bows, remove the 
 
 Gooseneck and Condyle Path Register. Loosen the trial plates so that 
 
 (Continued on Page 190.) 
 188 
 
Fig. VM. 
 Mountiuj: the trial plates an.l nuMlels by means uf The ('..iHlyle I'ath Register, and 
 the bent Ineisor (iuide I'in. 
 
 Fig. i:'.5. 
 Locating the Horizontal Position of the Rotation I'oints 
 
 189 
 
(Continued from Page 188.) 
 
 one can move on the other. Lift the Incisor Path Eegister Pin from the 
 Horseshoe Plate. Push both Rotation Points as near the median line 
 as j)ossible. Move the upper model laterally and see if the center of 
 the Incisor Path Register follows the outline of the pattern on the 
 Horseshoe Plate. Move the Rotation Point in action for that movement 
 outward until it does follow, and lock it in that position. Adjust the 
 other Rotation Point so that the Incisor Path Register follows the 
 other side of the pattern on the Horseshoe Plate. Then lower the pin 
 of the Incisor Path Register and make sure that it follows the margins 
 of the pattern as closely as possible in both lateral movements. 
 
 If the pattern on the Horseshoe Plate was unlike on the two sides 
 of the median line, the Rotation Points will be unequally distant from 
 the median line. 
 
 The articulator and trial plates are now ready for the teeth. 
 
 ATTACHIXG THE MODELS TO THE GYSI SIMPLEX ARTIC- 
 ULATOR. 
 Pigs. Xos. 136, 137, 138, 139. 
 
 The models may be attached to this articulator by the use of the 
 Snow Face Bow or by establishing on the articulator the equilateral 
 triangle commonly referred to as "Bonwill's triangle." 
 
 If the Snow Face Bow is to be used, the semicircular end of the 
 Mouth Piece accompanying the Bow must be warmed and thrust into 
 the labial surface of a trial plate, preferably the upper, a short distance 
 above the occlusal plane, and as nearly parallel with the occlusal plane 
 as is convenient, and with the stem of the Mouth Piece projecting 
 forward in the median line of the plate. It must be iirmly seated. 
 
 The location of the head of each condyle is marked on the face. 
 The trial plates, fastened together in proper biting relations, and with 
 the mouth piece attached as described, are placed in the mouth and the 
 patient is asked to close the jaws into them. 
 
 When the trial plates and mouth piece are in position, the Face 
 Bow is passed about the face, the stem of the Mouth Piece goes through 
 the swivel nut, and the ends of the pointers are placed over the marks 
 locating the heads of the condyles. The swivel pointers are pressed iirmly 
 in against the face, and the bow is moved from side to side until an equal 
 number of marks on each pointer is between the lock nut and the face. 
 The lock nuts about the swivel pointers are then tightened. 
 
 The lock nut of the swivel block is then tightened very firmly. This 
 locks the mouth piece in proper relations to the arch of the Face Bow. 
 It establishes the distance of the incisor point from the condyles as it 
 is in that patient, and the correct relation of the incisor point to the 
 median line. 
 
 The lock nuts about the pointers are now loosened, the pointers 
 moved outward, the patient is asked to open the mouth, and the arch, 
 mouth piece and trial plates are removed as one piece. The models may 
 
 190 
 
ATTAC'lIlXCi THEMODELS TO THE GVSl SIMl'LKX AimC- 
 ULAT( )K, ( ( 'ontiuucd ). 
 
 now be poured into the trial plates and Iriniiiied for mount ini^- on the 
 articulator. 
 
 On the condyles of the Gysi Simplex Articidator, will he found 
 two Face Bow Adapters for receiving the depressions in the inner ends 
 of the sliding pointers of the Face I>ow of the articulator. Tush the 
 sliding pointers as far in as they will go and lock them there. Lift 
 the upper model bow. Spring the ends of the sliding pointers over the 
 knol)s on the Face Bow Adapters. 
 
 Wet the models. Pour plaster over the lower model how and move 
 the models down into it until the occlusal plane of the trial plates is level 
 with the tahle on which the articulator sits. When the attachment^ to 
 the lower how is hard, remove the face bow and mouth piece by heating 
 the stem, wet the upper model and pour plaster on it, and bring the 
 upper model bow down until the pin is touching the Incisor Guide 
 Incline. The top of the pin shoidd be level with the top of the opening 
 which holds it. 
 
 If it is not desired to attach the models to the articulator by means 
 of the Face Bow, they may easily be attached so that distance from the 
 condyles to the incisor point shall be etjual to the distance between the 
 condyles. This forms BonwilTs Triangle. 
 
 On the Incisor Guide Pin will be found a pointed metal block called 
 The Incisor Guide, because it locates the incisor point in this method 
 of mounting. Plaster should be poured over the lower model bow and 
 the upper model bow closed so that the Incisor Guide Pin rests on the 
 Incisor Guide Incline, the top of the pin being flush with the top of the 
 opening in which it is held. The models having been previously wet, the 
 models and trial plates are passed between the model bows and so located 
 that the incisor point of the trial plates touches the Incisor Guide, while 
 the occlusal ])lane is on the l(!vel from the Incisor Guid(! to the projec- 
 tions on the inner sides of the upright part of the articulator frame. 
 Care should be taken that the models are located evenly on both sides 
 of the upper model bow. l^laster nuiy now be poured on the upper model 
 and model bow. 
 
 When the plaster has hardened, the attachmciit of the models to 
 the articulator is complete. 
 
 This method is open to the ol)j(!Ction that it is ])urely arbitrary and 
 is not suited to the recpiirements of tlie individual patient. It is, how- 
 ever, more satisfactory in this articulator than in other simple articula- 
 tors because the Kotation Points are here in the proper vertical position, 
 and, as explained in connection with Figs. Xos. !>4 and 05, this tact 
 has trreat influence on tlie ai't icnial ion of the dciihires. 
 
 191 
 
Fig. 136. 
 Patient with Snow Face Bow in position. 
 
 Fig. 137. 
 Trial plates mounted on Simplex articulator with Face Bow. 
 
 192 
 
Fifi. l:!S. 
 
 If the models be so mounted that the distance t<p the median line of the trial plates, 
 at the occlusal plane, equals the distance between the depressions on the horizontal plates 
 over the fossae, they will conform to Dr. Bonwill's measurements. The line O-O from the 
 center of the depression in The Incisor Guide Pin to the projection X' im the inner side 
 of the frame represents the proper level of the occlusal plane. 
 
 Models iiioiinti-d by nie.-iMs <,f t hr' Iijiisur (liiick 
 
 193 
 
PART VII. 
 
 Articulating The Teeth 
 
MAKIXG WAX TEIAL PLATES. 
 Fig. l\o. 140. 
 
 If the impression taking and trial plate making methods outlined in 
 Part I have been followed, the trial plates now on the models are made 
 of modelling compound and are not suitable for the arrangement of 
 the teeth. These trial plates must be replaced with others. 
 
 Before removing either of the trial plates, continue the median 
 line marked on the plates across both plaster models. Mark on the upper 
 plaster model a line parallel to the occlusal plane, as in Fi^'. No. 140, 
 line A-A. Mark olf on this line a distance from the median line equal 
 to the distance from the line A-A to the high lip line and a distance equal 
 to the distance from this line to the occlusal plane, so that if bj any acci- 
 dent the height of the bite is lost, it may be re-established. It is well 
 also to make a similar horizontal line on the lower trial plate and mark 
 the distance from the low lip line, and the occlusal plane. 
 
 Take the upper trial plate from the model, marring it as little as 
 may be. It may usually be removed by warming or carving the edges 
 of the impression part. Shape over the upper model a base and adapt 
 it carefully, especially between the rugae which have been made a little 
 higher than normal by carving the impression. Such adaptation may 
 prevent the trial plate taking a false position when tried into the mouth. 
 
 For such bases I prefer Dentsply Baseplate Composition because 
 it is stiffer than wax, does not need to be wired to prevent warping, as 
 wax does, and because in especial cases it may be strengthened by build- 
 ing additional composition about the rim in the same way that the mar- 
 gins of the impression were built up. It should be warmed over a small 
 flame, roughly adapted and trimmed and then further adapted until it 
 is of the form of the finished denture. 
 
 The ridge of the trial plate is to be made of baseplate wax, and 
 should be shaped like the ridge of the upper trial plate which has been 
 removed. This can usually be well done by building it out to the 
 margin of the lower trial plate, and then building the labial fullness up 
 as desired. 
 
 The kind of wax used for these ridges makes a good deal of dif- 
 ference in the future work* Some baseplate waxes hold the teeth well 
 in position, while others make it impossible to keep the teeth in position. 
 I believe the final work is often unsatisfactory because a wax was used 
 which allowed the teeth to easily change position during the final steps 
 of articulation. 
 
 In order that Prof. Gysi's method of automatic articulation may 
 be put into operation, the wax must hold the teeth well in position. I 
 prefer Dentsply Baseplate Wax for this purpose. 
 
 The lower trial plate of modelling compound is now removed from 
 the model, a base of baseplate composition is carefully adapted to the 
 ridge, and a wax ridge is built upon it after the manner employed in 
 making the upper trial plate. This plate should be given any peculiari- 
 ties of form which suit it to the case in hand. 
 
 196 
 
Fig. 140. 
 norizont.1 lines on upper and lower models, with distances to hi.M, and low lines 
 and occlusal planes marked on them. 
 
 iltff^SKTfS^V?^ ' 
 
 Fig. 141. 
 Setting upper anteriors, beginning at median line. 
 
 1 
 
 Fig. 14: 
 
 Setting lower .-us s In right relations to u| r .uspi.ls and laterals. 
 
 ]!)7 
 
SETTIIs^G THE A^'TERIOR TEETH. 
 Figs. ^^os. 141, 142, 143, 144, 145, 146. 
 
 Recesses may now be cut in the wax of the upper trial plate on one 
 side of the median line, and the upper central, lateral and cuspid for 
 that side put in position, making sure that their labial surfaces restore 
 the contour of the wax. 
 
 Set the upper central lateral and cuspid of the other side in like 
 manner. 
 
 The position given the upper and lower cuspids will have a great 
 eifect on the appearance of the denture. If the cuspids be rotated as 
 in Fig. ISTo. 000, the result will be pleasing, but if the distal portion 
 of the labial surface of the upper cuspid be inclined too much forward, 
 the appearance will be displeasing. This position will be governed 
 slightly by the width of the arch, but an effort should be made to turn 
 this surface as shown in the illustration. 
 
 When the upper anteriors are set, recesses are cut in the wax of the 
 lower trial plate and the lower cuspids are set. These are the most diffi- 
 cult teeth in both dentures to arrange, and a little care spent at this 
 time will be repaid in better results. 
 
 The distal angle of each lower cuspid should come just below the 
 tip of the upper cuspid. The distal facet on the cutting edge of the 
 lower cuspid should occlude with the mesial facet on the upper cuspid, 
 while the mesial facet on the cutting edge of the lower cuspid should 
 occlude with the short facet on the distal portion of the cutting edge 
 of the upper lateral. On all teeth except T mbyte teeth, it will be neces- 
 sary to grind these facets with care. When the jaw moves laterally these 
 teeth must articulate without leaving contact. A careful study of the 
 relations shown in Figures 143 and 144 will be helpful in learning to 
 establish these relations. 
 
 When both lower cuspids are in correct positions, the lower incisors 
 may be set between them. Some little grinding may be necessary 
 on the distal surfaces of the lower laterals to establish right relations, 
 and it may be thought that this is an evidence that the teeth have not 
 been carefully manufactured. If much grinding is necessary, such a 
 conclusion is just, but when only a little grinding is required, the con- 
 clusion is not just. 
 
 The ideal arrangement of the lower anteriors is for them to under- 
 bite the upper anteriors, just enough so that the lower incisors are out of 
 contact with the uppers when the jaw is in central occlusion, and so that 
 the edges of the uppers and lowers articulate during lateral movements. 
 Very deep underbites should not be sought, since they tend to dislodge 
 the dentures, and since they are hardly possible with correct relations of 
 the upper and lower cuspids. Fig. 145 illustrates correct and incorrect 
 incisor relations. 
 
 198 
 
Fig. 143. 
 Above, correct vertical relations of upper 
 ind lower anteriors. Below, correctly 
 "ormed facets on lower cuspid. Lower 
 ;uspid properly rotated and bicuspids 
 partl.v hidden behind it. 
 
 Fig. 145. 
 The effect on the stability of the dentures 
 and on the expression of correct and incor- 
 rect relations of upper and lower incisors. 
 
 CUSPID 
 REUATIONS 
 IN CENTRAL 
 OCCLUSION 
 
 0. 
 
 CUSPID 
 
 BELATIONS ON 
 THE WORKING , ,.,^ 
 SIDE IN lateral/ T^ 
 ARTlCULATfON 
 
 Fig. 144. 
 
 Fig. 140. 
 A straight edge laid on the mesial facet 
 of the upper cuspid, as liere shown, will 
 touch tlie gum at the mesio-lingual root of 
 tlic lirst iiiohir of the (ppposite side. 
 
 IDD 
 
SETTING THE AXTEKIOR TEETH— Continued. 
 
 Figs. Xos. 147 and l-iS. 
 
 The beauty of the dentures will be largely influenced by the posi- 
 tions of the anterior teeth. 
 
 The first of these relations to attract the dentist's attention is that 
 determined by the distal divergence of the roots. In the typical case, 
 the roots of the upper centrals are parallel; the roots of the upper 
 laterals diverge distally from those of the centrals; the roots of the 
 upper cuspids diverge distally less than do the laterals ; the roots of 
 the two upper bicuspids are parallel with those of the upper centrals, 
 and the root axis of the upper first molar actually slopes forward 
 toward the centrals. These relations are shown in Fig. ]^o. 147. 
 
 The roots of the four lower incisors do not diverge distally from 
 the median line, but the roots of the lower cuspids diverge distally in 
 a marked degree. The root positions of the lower bicuspids and molars 
 will be determined by articulation with the upper teeth. 
 
 The labial inclination of the anteriors is equally important, be- 
 cause more dentures are made to look unnatural from errors in this 
 inclination than in any other. The tendency is always to place the 
 necks of the incisors too far forward in relation to the positions of the 
 cutting edges. As can be seen by reference to Fig. jSTo. 145, this gives 
 the lips an unnatural fullness. 
 
 The correct inclination for the upper centrals is shown in "c" of 
 Fig. 'No. 148. This inclination brings the facets on the cutting edges 
 into the most effective articulation with the edges of the lower incisors. 
 The neck of each upper lateral is set a little farther back than the necks 
 of the upper centrals, as shown in ''1" of Fig. jSTo. 148. 
 
 The upper cuspids stand more nearly upright than either the 
 centrals or laterals. This helps to build up the cuspid eminences as 
 shown in "C" of Fig. ISTo. 148. The articulating facets on the cuspids 
 are but little inclined upward from horizontal. 
 
 The labial positions of the lower centrals, laterals and cuspids, 
 are shown in '^c," "V and "C" of Fig. :^o. 148. The edges of the lower 
 centrals incline strongly forward. Dentures are very common in which 
 these teeth are either set vertically or inclined inward. The effect on 
 the expression of the lip is shown in Fig. jSTo. 145. 
 
 The lower cuspid necks are prominent and help build out the cus- 
 pid eminences. The articulating facets on the lower cuspids are parallel 
 to those on the upper cuspids. 
 
 200 
 
Fit;. l^T. 
 Mesio-Distal iiiclhiiitiou <>f the tectli. 
 
 The roots of the upper centrals are parallel. The roots of the upper laterals and 
 cuspids diverge from the median line, the laterals diverging slightly more than the 
 cuspids. The roots of the upper bicuspids are parallel with those of the upper centrals, 
 while the roots of the first molars incline slightly toward the mesial. This position of 
 the upper first artificial molar is probably a compromise betv\een the positions of the 
 first and second natural molars. 
 
 The roots of the lower centrals and laterals are parallel, but those of the lower 
 cuspids diverge strongly. 
 
 Fig. 148. 
 Forward inclinations of the anterior teeth. 
 
 The best effects are obtained by inclining the upper centrals as shown at "c." This 
 not only gives the most pleasing esthetic effect, but brings the facets on the cutting 
 edges into the inclination wliich articulates most efliciently with the lower incisors. 
 
 The necljs of the ujiper laterals should sit bacli more than those of the upper centrals, 
 though the rutting edges are nearly as far forward. It will be noted that the articulating 
 facet on the cutting edge is less steeply inclined than that on the central. This is the 
 inclination of the mesial facet on the lateral. 
 
 The cuspids stand more nearly vertical tlian either the centrals or laterals, and the 
 facets on the edges are nearly horizontal. 
 
 The lower centrals slope strongly outward from neck to incisal edge. This pre- 
 vents the over fullness of the gums so common to lower dentures, and illustrated in 
 Fig. No. 14."*. 
 
 The lower laterals slope outward very much less th;in do the centrals. 
 
 The necl{s of the lower cuspids an; very prominent while tlic cutting edges are 
 pretty well back. This causes the necks t<. be prominent iind lill (nit tlie cuspid eminence, 
 and causes the teeth to slope inward frnni the gum up. 
 
 201 
 
RELATIVE WIDTHS OF UPPER AND LOWER AN^TERIOR 
 
 TEETH. 
 
 Fig. N^o. 149. 
 
 It is rare that the upper and lower anterior teeth go exactly to 
 place without some grinding of one set or the other to establish correct 
 relative widths. The amount of grinding depends on the care with 
 which the manufacturer has complied with the requirements of articu- 
 lation, on the particular arrangement of anterior teeth favored by the 
 dentist, and on the articulating movements in the case in hand. The 
 best results will be obtained if the dentist and manufacturer both under- 
 stand what part of the work each should perform. 
 
 It is the manufacturer's duty to supply upper and lower anteriors 
 of such relative widths that the dentist can easily adapt them to the 
 requirements of any ordinary case. They should not be much too wide 
 for the dentist who wishes to set the lower incisors pretty well back ot 
 the upper incisors, or much too narrow for the dentist who wishes to set 
 them irregularly. 
 
 On the other hand, the dentist must not expect that the manu- 
 facturer can supply upper and lower anteriors which are of exactly 
 the correct relative widths to permit different forms of arrangement. 
 This would require hundreds of moulds of anteriors, nor could the 
 dentist know which of the hundreds of moulds was needed until he set 
 the teeth on the case. He, the dentist, should recognize it as his task 
 to adapt a correctly formed product to his own special requirements. 
 
 The widths of the upper and lower anteriors are affected by the 
 horizontal location of the rotation points, as is made clear by a study 
 of Fig. ]^o. 149. The large diagram shows the path of the buccal 
 cusp of the upper first bicuspid in three different horizontal locations 
 of the rotation points. When the rotation points are in the position 
 marked ''R i," the upper bicuspids move through the path marked "R i." 
 When the rotation point is opposite the condyles, the upper bicuspids 
 move through the path marked ^'R m." When it is outside of the 
 condyles, the upper bicuspids move through the path marked "R a." 
 The practical application of these movements to the width of the upper 
 and lower anteriors is seen in Figs. D-E-F. 
 
 In Fig. 149D the relative widths of upper and lower anteriors 
 necessary for the path "R i" is shown. The upper anteriors are here 
 quite a little wider than the lower anteriors so that the tip of the 
 upper cuspid may pass through the interdental space distal to the lower 
 cuspid during lateral movements. In Fig. 149E the tip of the upper 
 cuspid is just above the distal angle of the lower cuspid. In Fig. 149F 
 the tip of the upper cuspid is just anterior to the distal angle of the 
 lower cuspid, in order that it may pass through the interdental space 
 posterior to the lower cuspid when the rotation point is located at "R.a." 
 
 Trubyte teeth are designed to produce the cuspid relations shown 
 in Fig. 149E, with a minimum of grinding. 
 
 202 
 
R.i D 
 
 R.m E 
 
 R.a F 
 
 Fig. 149. 
 
 Diagram showing three paths of the upper left first bituspid with three different 
 horizontal locations of the rotation points. "R i" indicates a location of the rotation 
 points between the condyles and the median line. "R m" indicates a location at the 
 condyles, and "R a"' a location outside the condyles. 
 
 The movements of the upper first bicuspid are indicated by the paths numbered 
 like the rotation point fiM.ni which each movement is inscribed. 
 
 The movements of the incisor point are shown by three paths drawn from the incisor 
 point and numbered like the centers from which they are taken. 
 
 The figures "D-E-F" show the relative wi<lths of the upper and lower anteriors 
 ne«essary to make possible the correct movement of the points of the upper cuspids 
 through these three paths. 
 
 It will be noted that in Fig. 1» the points of the upper anteriors are quite a little 
 wider than the lower anteriors and the points of the upper cuspids need to come a little 
 to the distal of the distal angles of the lower cuspid, to make it possible for the point 
 of the upper cusjjid to follow the path "It i." 
 
 In Figure F the points of tlic upper cuspids need t.i come a little anterior to the 
 distal angle of the lower cuspids, to inaUc it possihh- to follow the path "U a." 
 
 This diagram helps make it idiiiii why a given width of upper and lower anteriors 
 Is not e.xactly suitable for .til cases. 
 
 2o;j 
 
GRI1^^DIXG A^^TERIOR TEETH TO FORM. 
 Figs. Xos. 143, 144-, 146, 148, 149. 
 
 Dentists who prefer not to use Trubyte teeth may grind an}^ other 
 anterior teeth to such articulating forms as the teeth permit and their 
 own skill makes possible. A few simple directions for such grinding 
 may be helpful. 
 
 The cutting edges of the upper incisors should present facets for 
 articulation with the lower anteriors. If the teeth are to be set in the 
 typical positions shown in Figs. ISTos. 143 and 144, the facets should 
 be of the forms shown in Fig. ]Sro. 146 and have the inclinations shown 
 in Figs. N^os. 144 and 148. 
 
 It will be noted that the cutting edge of each upper lateral pre- 
 sents two facets, of which the mesial is the longer. This mesial facet 
 articulates with the cutting edge of the lower lateral, and should have 
 the inclination of the facet shown in the upper lateral in Fig. ISTo. 148. 
 The distal facet articulates with the mesial facet on the lower cuspid 
 and should be of a length to correspond to the facet which is to be 
 ground on that cuspid. As this cannot always be known in advance, 
 it will doubtless be necessary to try the teeth in position and adjust the 
 lengths of the facets. 
 
 Care should be taken not to grind this distal facet on the upper 
 lateral at the same inclination as the mesial facet, since its inclination 
 should correspond in all directions to the inclination of the mesial facet 
 on the lower cuspid. It must be borne in mind that this distal facet 
 on the lateral is to both articulate and occlude with the lower cuspid. 
 
 The mesial facet on each upper cuspid will be of the general form 
 shown in Fig. jSTo. 144, but it will be governed somewhat by the relative 
 widths of the upper and lower six anteriors, as received from the manu- 
 facturer and the positions in which the teeth are set. The important 
 point is that the tip of the upper cuspid must pass through the inter- 
 dental space between the lower cuspid and first bicuspid during lateral 
 movements, and that the upper and lower cuspids on the working side 
 should both occlude and articulate as long as the dentures are in contact. 
 
 In order to bring about these relations, it will probably be best 
 to grind the upper incisors and cuspids to place, and then the lower 
 cuspids, governing the grinding by the necessity of establishing right 
 relations during occlusion and articulation. The inclination of the 
 facets on the upper cuspids will be as shown in the drawings of the 
 cuspids in Fig. ]^o. 148, and the relations which are to be established 
 are shown in Fig. l^o. 149. If the teeth are all in position before the 
 grinding is begun, the inclination of the facets on the upper cuspids 
 
 204 
 
GRIXDIXG AXTEHIOK TEETH TO FORM.— Continued 
 
 may be determined by shaping the facets so that a match laid on them, 
 as in Fig. Xo. 14G, will come at the mesial root of the upper first molar, 
 as there shown. 
 
 The difficulty which I have experienced in grinding tliese facets 
 and which has been experienced by practically all whom I know, is an 
 unwillingness to grind the mesial facets long enough on the upper 
 cuspids. There seems to be a strange unwillingness to do this, and 
 even after careful demonstration I have found men leaving these 
 facets so short that the point of the upper cuspid passes over the 
 lower cuspid in articulation, a serious fault. 
 
 One is somewhat deterred also by the fact that grinding those 
 cuspids which have not been shaped correctly, often spoils the appear- 
 ance of the tooth, and sometimes shortens it so that it is no longer 
 suital)le for the case. 
 
 It is not usually necessary or desiral)le to grind facets on the 
 cutting edges of the lower incisors, the edges they present l>eing suffi- 
 cient for all practical purposes. 
 
 It is however essential to grind facets on the lower cuspids, a 
 short facet on the mesial of each, and a long facet on the distal, as shown 
 in Fig. Xo. 143. 
 
 The short mesial facet must be of the same length as the distal 
 facet (»n the opposing upper lateral, so that when the teeth are occluded 
 the tip of the lower cuspid shall be opposite the interdental space be- 
 tween the upper lateral and cuspid. Tliese facets must be of such in- 
 clination that the lateral will not be forced out of place by articula- 
 tion with the cus])ids. I find this a most dangerous point for a contact 
 which dislodges dentures during articulation. 
 
 The distal facets on the lower cuspids are of the same length as 
 the mesial facets on the upper cuspids, so that the distal angle of each 
 lower cuspid is dii'octly l)elow or slightly mesial to tlie tip of the upper 
 cuspid. This rcUition will be slightly affected l>y the location of the 
 rotation points if The Oysi Adaptable Articulator is used, but the 
 distal angle of the lower cuspid does not often come distal to the lip 
 of the upper. The inclination of this facet must he coniplementarv to 
 that on the opj)osiiig facet of the upper cuspid, as shown in the draw- 
 ings of these teeth in Fig. Xo. 148. The best method of getting the 
 inclination of this facet is to place the upper aiul lowei' cuspids in 
 position and grind the distal facet on the lowci- so that it is parallel 
 to tlie jru'sial facet of tiu; upjjei- with which it aiM iculates. 
 
SETTIiq^G UP THE BICUSPIDS AND MOLARS. 
 
 Fiss. Nos. 150 to 159 Inclusive. 
 
 '■fa'- 
 
 Prof. Gysi's methods of articulating bicuspids and molars are so 
 much shorter and better than those I advocated in the book entitled 
 "The Mechanical Side of Anatomical Articulation" that I have given 
 up the working out of the articulating curves and now follow his meth- 
 ods, which I am glad to present here. The technic is rather long to 
 describe because so many specifications are required, but is really 
 shorter than most other methods, once it has been mastered. These 
 methods are, in brief, to set the upper bicuspids and molars in certain 
 positions against the flat occlusal surface of the lower trial plate, 
 establishing the curves by tilting the teeth laterally; to set the lower 
 teeth to occlusion with the uppers and then make them perfect their 
 own articulation by a method which he calls "automatic articulation." 
 To employ this method, he sets both the upper and lower bicuspids and 
 molars higher than they are to be in the finished denture and makes 
 them adjust each other by pressure as they are closed together. 
 
 When the upper and lower anteriors are set and waxed firmly to 
 position, open the bite about 1.5 m.m. (1/16 inch) by moving the 
 Incisor Guide Pin downward and locking there. Set the upper bicus- 
 pids and molars of both sides in contact with the lower trial plate, as in 
 Fig. 1^0. 150. Then raise the bite another 1.5 m.m. and set the lower 
 bicuspids and molars to occlusion with the uppers. This leaves the 
 upper and lower anteriors separated 3 m.m. and the upper and lower 
 bicuspids and molars in occlusion. 
 
 The arrangement of the teeth will be determined in large part by 
 the type of arch. All arches may be described under three headings, 
 as narrow, medium wide, or broad. As Dr. Williams showed long 
 ago, the form of the arch is closely parallel to that of the face just 
 below the level of the eyes, and it is neither good mechanics nor good 
 esthetics to try to make all arches conform to one type. 
 
 Illustrations of the three types of arches are shown in Figs. ISTos. 
 152, 153, and 154. Fig. 152 represents the medium arch. The 
 lines touching the mesio-buccal ridges of the first molars, the buccal 
 ridges of both bicuspids and the labial ridges of the cuspids meet at the 
 point "C" which is nearly as far in advance of the point "B" as the point 
 "B" is in front of the point "A." The triangle B-B-B is equilateral, and 
 so is the small triangle in dotted lines, with its apex at the point "A" 
 and its other termini at the distal angles of the cuspids. It will be noted 
 also that the straight lines which touch the distal portions of the buccal 
 surface of the first molar and the buccal surfaces of the second molars 
 are nearly parallel. 
 
 In arches of the narrow type. Fig. 'No. 153, the arch between the 
 cuspids is not as narrow as might be expected. It is, if anything, 
 flatter than in the medium arch. The bicuspids and molars are ar- 
 ranged in straighter lines and more directly back of the cuspids. The 
 lines touching the cuspids, bicuspids and molars do not converge at 
 
 206 
 
Fig. 150. 
 
 When the upper and lower anteriors have been arranged at the desired height of bite, 
 the articulator should be opened about 1.5 m.m. (1-16 inch) and the upper bicuspids and 
 molars on both sides set into place. 
 
 The articulator should then be opened another 1.5 m.m. and the lower bicuspids and 
 molars of both sides set in position to occlude with the uppers. 
 
 The difference of 3 m.m. in height permits the use of Prof. Gysi's method of automatic 
 articulation, by which the teeth may be adjusteil to articulating positions. 
 
 Fig. 151. 
 
 If a iiifce of cigar box be sipiared to a size of about three Inches, it will be found 
 very UHeful In determining tlie positions of the teeth. 
 
 207 
 
SETTIis^G UP THE BICUSPIDS AND MOLARS— Contimied. 
 
 the point ^'C" but farther forward. The lines touching the first and 
 second molars converge slightly more than the similar lines in the 
 medium arch. The base of the equilateral triangle B-B-B does not 
 terminate in the buccal grooves, as in the medium arch, but extends to 
 the buccal surfaces of the second molars. 
 
 In arches of the wide type, Fig. ISTo. 154, the arrangement of 
 the upper anteriors is very similar to that in the medium arches, and 
 the positions of the second molars are almost identical. The first 
 molars are rotated so that the mesio-buccal cusps are farther from the 
 median line and the longitudinal groove is more nearly straight for- 
 ward and back. The bicuspids are not so directly behind the cuspids, 
 and the lines touching the cuspids, bicuspids and first molars converge 
 before they reach the point "C." 
 
 If the trial plates have been carved to restore the fullness desired 
 in the patient's face, the curves of the bicuspid and molar region will 
 probably indicate which type of arch the case presents. 
 
 If a small piece of wood, preferably cigar box wood, be cut to 
 the form of a square, three inches on a side as in Fig. No. 151 will 
 prove very useful in establishing the relations indicated by the several 
 lines in Figs. Nos. 152, 153, 151-. 
 
 Having determined the type of arch, the upper bicuspids and' 
 molars are set with their vertical axes in the lines shown in Fig. No. 
 155. The buccal cusp of the upper first bicuspid touches the occlusal 
 surface of the lower trial plate, but the lingual cusp does not quite 
 touch. Both cusps of the upper second bicuspid touch the wax. Both 
 lingual cusps of the upper first molar touch the wax, but the buccal 
 cusps are elevated about a millimeter above the wax and begin the 
 compensating curve formed by the buccal cusps of both upper molars. 
 
 The lingual cusps of the upper second molars are in contact with 
 the opposing trial plate, but the buccal cusps are elevated about 2 m.ni. 
 above the wax. They continue the compensating curve which the buccal 
 cusps of the first molars began. 
 
 It is necessary, while establishing these relations, to secure such 
 positions of the teeth over the ridges as will give the dentures maximum 
 stability and efficiency. This can be done best by keeping the teeth 
 below the upper alveolar ridge, after the manner shown in the upper 
 illustration of Fig. ISTo. 156. Properly articulated dentures are not 
 easily dislodged during articulation, even if the teeth are outside the 
 ridge. But during the time when the mouth is open and the dentures 
 do not support each other, dentures are more easily dislodged if the 
 upper teeth are set outside the ridge. In all cases, the molars and 
 bicuspids should be kept^as nearly in line with the ridges, as the other 
 conditions of the case permit. If the trial plates were formed after the 
 manner shown in Fig. No. 156, the teeth should come in these positions 
 merely by setting them in proper relations to the opposing wax. 
 
 208 
 
A 
 
 Fig. lo2 
 
 Fig. 1.-..".. 
 
 Fig. 154. 
 
 Fig. Nil. l.K represents an of(liis;il view (if the medium arch on the basis of Dr. 
 Bouwill's theory. The triangle B — IV — B- is equal sided. It will be noted that one point 
 rests between the points of the upper incisors and the other points at the distal ends 
 of the longitudinal groove on the occlusal surfaces of the upper second molars. 
 
 The outside converging lines which meet at the point "<_"' touch tlie buccal ridges of 
 the cuspids, the bicuspids and the mesio-buccal ridges of the first molars. The distance 
 from the point "C" to the point "B" is nearly equal to the distance from "A" to "B." 
 
 Fig. No. 153 represents the narrow arch in the same way. The equilateral triangle 
 no longer ends in the longitudinal groove of the second molars, but extends outside of the 
 disto-buccal angles. The lines which touch the molars, the bicuspids and the cuspids, 
 do not meet at the point "('" but considerably in advance of it. 
 
 Fig. No. 154 represents a siiuilar view of the broad arch. This arch is distinguished 
 by its width in the bicuspid se<ti()n rather than in the region of the second molars. The 
 posterior ends of the equilateral triangle end about where they did in the medium arch, 
 but the bicuspids set so much farther out that the lines which touch the molars, bicuspids 
 anil cuspids converge long before they reach the point "C." 
 
 I'i;:. l-'i."i. 
 
 "I"" indicates the proper vertical position of tlic upper lirst bicuspid against the 
 occluHal Hurface of the lower trial plate, "pa" indicates the position of the second upper 
 bicuspid. ".M'" Indicates the i)osltion of the upper first molar and "M^" the position of 
 the u|iiier second molar. 
 
 200 
 
SETTING UP THE BICUSPIDS AND MOLARS— Continued. 
 
 Fig. 156. 
 
 1 
 
 Fig. 157. 
 
 Diagrammatic illnstratiou of good and false relations of the upper posteriors to the 
 ridge. If the upper molars are kept in the line from the crest of the upper ridge to the 
 crest of the lower ridge, the dentures will be more stable in position. 
 
 When the teeth have been placed in these positions, the relations 
 may be tested by means of the little piece of squared wood. With a 
 pair of dividers, the terminations of the triangle here marked B-B-B 
 may be located as guides in establishing right proportions in normal 
 cases. 
 
 When the upper bicuspids and molars have been set in the eleva- 
 tion of 1.5 m.m. above the upper anteriors, the articulator is opened 
 1.5 m.m. additional, and the lower bicuspids and molars are set to 
 occlusion with the uppers, and both sets are waxed firmly in position. 
 The relations of the teeth are established as accurately as possible with- 
 out making lateral movements of the articulator and without grinding 
 the teeth. They will be very much easier to establish if correctly 
 formed teeth are used. Indeed, unless such teeth are used, the steps 
 which are to follow cannot well be performed. 
 
 The teeth are now more accurately adapted by a process which 
 Prof. Gysi calls ''automatic articulation." 
 
 210 
 
Fig. 158. 
 By means of the piece of vigar box, tlie degree of outwiird inclination given to any 
 of tbe teetli t-au be easily seen, and botli sides can be k;ept alike. This is especially nseful 
 when, for any reason, the trial plate has been taken from the model. 
 
 INCLINATION OF COMPENSATING 
 CURVE FOR SHALLOW 
 OVERBITE OF 
 ANTERIORS. ■ 
 
 OCCLUSAJ 
 
 COMPENSATlNi 
 FOR OEFP OVERI 
 OF ANTERIORS 
 BJCCAL *N0 LIMSOi 
 CUSf.=^ iNCLUDEO, 
 
 ^^^^iiiH^ 
 
 '^^^^>. 
 
 
 '■<'^Suir^l''s 
 
 %#itii^ 
 
 Fig. 159. 
 
 In cases where tlie iintcriors e.xliibit shallow overbite, the compensating cnrve of tlie 
 upper teeth does not include the disto-lingual cusps of the upper first molars or the 
 meslo-llngual cusps of the upper second molars. Kut in cases where the upper anteriors 
 exhibit deep overbite, the coniiiensating curve of the upi)er teeth lifts the disto-lingual 
 cusps of the u[)per first molars and the mesio-lingual cusps of the second molars above 
 the oc<lnsal plane. 
 
 211 
 
AUTOMATIC AllTIC UL ATIOK 
 Fig. ^^o. 160. 
 
 This is a process of making the teeth adapt themselves to exact 
 positions by throwing the dentnres into lateral occlnsion and pressing 
 them together first on one side and then on the other. It can be put 
 into advantageous execution only after the bicuspids and molars have 
 been set at higher than ordinary levels, as described on page 206 to 210 
 inclusive. 
 
 The Incisor Guide Pin is raised about 1 m.m. out of contact with 
 the Inclined Plane and the set screw tightened. The wax about the 
 necks of the teeth is slightly warmed so that the teeth can be moved 
 by pressure. The articulator is opened and moved into lateral occlu- 
 sion on one side and closed with the upper and lower buccal cusps of 
 that side interdigitated. Slight pressure is exerted. 
 
 The denture is then opened and returned to a position of central 
 occlusion and pressure is exerted in that relation of the dentures. The 
 wax about the teeth is kept in such a state of softness by occasional 
 warming, as permits the adaptations of one set of teeth by the other. 
 The wax can be warmed for this process best by applying the heat of 
 a small flame to the occlusal surfaces of the bicuspids and molars, and 
 letting it reach the wax through the porcelain. 
 
 The dentures are now carried into a position of lateral occlusion 
 on the side opposite that first occluded, and pressure is made with the 
 buccal cusps interdigitated. They are then returned to the position 
 of central occlusion and pressed together. 
 
 By this time it will be necessary to lift the Incisor Guide Pin an- 
 other millimeter out of contact with the Inclined Plane and tighten 
 the set screw. The former steps are then repeated until the pin comes 
 into contact with the Incisor Guide Incline. A third lifting of the pin 
 will bring the upper and lower anteriors into articulating relations. 
 
 A few points require especial attention during this process. First 
 of all, the teeth must be mounted in a wax which holds them against 
 sliding. Some waxes defeat the efforts to automatically articulate den- 
 tures because the teeth slide so that it is impossible to keep them in 
 position while exerting pressure in lateral occlusion. I have failed 
 with several waxes but have had good results with Dentsply Baseplate 
 wax. 
 
 The teeth must be held on the buccal surface against the tendency 
 to slide which results from pressure in lateral occlusion. If the thumbs 
 are placed against the buccal surfaces of the bicuspids and molars dur- 
 ing the time of pressure, slipping can be prevented. Fig. No. 161 
 shows how Prof. Gysi holds dentures for automatic articulation. 
 
 jSTo sliding movements should be made during this operation. The 
 teeth are probably not accurately adapted, and such movements will 
 merely dislodge them. 
 
 212 
 
Kit,'. lilO. 
 
 In tlif Mt '■oliiinii side views of I he scvcriil pusitions in imtoiiiatii- arti<uhiti(in. In 
 the rljilit <'i>lnnin, rear views of tlie same positions. 
 
 2J3 
 
AUTOMATIC ARTICULATION^— Continued. 
 
 Fig. 161. 
 
 Prof. Gysi holding the teeth from sliding during the movements of automatic 
 articulation. 
 
 If automatic articulation is properly carried out it establishes 
 in a few moments relations which most of us have spent hours seeking 
 to establish by other methods. It adjusts the inclinations of the 
 several teeth to the movements of the mandible of the articulator. In 
 cases where the Gysi Adaptable Articulator is used, that means to the 
 movements peculiar to the patient. 
 
 It determines the steepness of the compensating and lateral curves 
 better than it can be done by any other method. In cases where the 
 overbite of the incisors is shallow, this curve will include only the 
 buccal cusps of the first and second molars and the disto-lingual cusps 
 of the upper second molars. In cases where the overbite of the incisors 
 is deep, this curve will affect the lingual cusps of both molars as can 
 be seen from a study of Fig. No. 159. 
 
 Automatic articulation also rotates the teeth on their vertical axes 
 to afford the most satisfactory relations with the opposing teeth. 
 
 The intelligent dentist who masters the slight technic of this oper- 
 ation, will appreciate more than ever before the skill with which Prof. 
 Gysi has formed Trubyte bicuspids and molars, because with them re- 
 lations may be very quickly and satisfactorily established. With some 
 forms of teeth this method is ineffectual because the teeth are not 
 shaped to make it effective. 
 
 214 
 
GRIXDIXG THE TEETH TO EIXISHED ARTICULATION 
 
 When the process of automatic articuhitioii has been completed, 
 the teeth should be in the most advantageous positions which can be 
 secured by moving each tooth as a whole. The articulation must be 
 completed hx grinding. 
 
 There seems to be a general impression among dentists that the 
 need for grinding is evidence that the teeth are not correctly formed, 
 and that if they were rightly formed no grinding would be needed. 
 Such an idea is a mistake. 
 
 If teeth require to be extensively ground to permit articulation, 
 it is evidence that they w^ere not rightly formed or not rightly selected 
 or placed. But grinding has its proper and important place in the 
 scheme of articulation, and dentures which have been properly ground 
 are better than those which have not. 
 
 P>ut little if any grinding should be necessary with a stone. Occa- 
 sionally a little porcelain will flow out of its appointed place and will 
 need taking down with a stone. Occasionally the conditions of the 
 case will require minor adjustments of widths with a stone. But no 
 reshapinu' of the teeth or other extensive changes should l)e necessary. 
 The articulation of the dentures is finished by grinding the sets 
 tou'ether with a paste of carborundum powder and glycerine between 
 the cutting edges and occlusal surfaces. The dentures should be held 
 in contact\vith light but firm pressure and made to perforni the lateral 
 movements of mastication. This may be continued until the right 
 relations are established to the dentist's satisfaction, and the proper 
 facets have been perfected on the anteriors and formed on the bicuspids 
 and molars. This should not require more than 20 minutes. 
 
 The formation of these facets on the bicuspids and molars is very 
 important to the efficiency of the dentures, and they cannot be formed 
 in any other manner than by grinding the sets together in this manner. 
 It may be helpful to some to understand just why these facets 
 cannot l>e formed by the manufacturer and why they mnst be formed 
 by the dentist. They cannot be formed by the manufacturer, because 
 they cannot be formed at all until the teeth are articulated. The utmost 
 that the manufacturer can do is to furnish teeth properly formed to 
 receive the facets. That requires the most extensive knowledge of 
 articulation and the most advanced methods of tooth formation. 
 
 The facets cannot be formed until the teeth are articulated because 
 tlieir location and extent are determined by the positions of the teeth 
 and no one can foresee those positions. The facets have little value if 
 the facets of one set are not complementary to those of the other set, 
 so that the edges, when passing, cut up fibres and the surfaces roll the 
 cells and smash the cell walls. 
 
 The grinding removes the glaze from the facets and leaves it on 
 the other portions of the occlusal surfaces so that food shall not lodge 
 there. 
 
 215 
 
Fig. 102. 
 
 Photograph showing upper and lower dentures in a practical case after they had 
 been ground by automatic articulation and the facets had been perfected on the cutting 
 edges of the anterior teeth and formed on the occlusal surfaces of the biciispids and 
 molars, by rubbing the sets together in lateral movements with a paste of carborundum 
 ^d glycerine between them. 
 
 The facets indicate clearly what portions of each tooth are in articulation with the 
 opposing tooth during movements to both sides. By far the larger portion of each 
 surface never enters into articulation when the teeth are properly formed. The portions 
 which articulate in a single lateral movement are relatively small, since it proved impossi- 
 ble to here separate the facets engaged in one movement only, and more than one facet is 
 here shown in nearly every ground section. 
 
 While the margins of the facets are not sharp in the way a knife is, they are 
 clearly differentiated from the rest of the tooth surface and are sharp enough to cut 
 food when drawn across opposing facets. 
 
 Enough power can be transmitted through dentures to make teeth formed and 
 articulated in this way effective in mastication, when the ordinary forms of teeth 
 would be wholly ineffective. 
 
 216 
 
Fig. 103. 
 
 How properly formed teeth masticate food. This is from a 
 photograpli of a sheet of modelling compound into which properly 
 articulated sets of Trubyte teeth were closed. The rather wide and 
 shadowy outline shows where the crowns of the teeth l)it into the com- 
 pound. The smaller, lighter areas show where the teeth bit practically 
 through the compound. 
 
 It will be noted that the teeth nowhere bit through in a large area, 
 but at all the points of closest opposition of the teeth are smalL It 
 will be noted also that each spot of close approximation resembles 
 somewhat a short knife blade, blunt when compared to a real knife, but 
 sharp when compared to the opposed areas of artificial teeth in the past. 
 
 Xo lateral movements were made in this case, but it is easy to see 
 that with .so many small, closely opposed areas, the lateral movement 
 of the teeth would be very efr'ective in masticating the food. 
 
 The relatively small power whicli can be transmitted through 
 artificial dentures can make these small areas effective, in cutting up 
 the fibres and in smashing the cell walls so that th(; contents of the 
 cells may be insalivated. 
 
 217 
 
TRUBYTE MOLAE BLOCKS. 
 Fig. No. 164. 
 
 Prof. Gysi has perfected an improvement in bicuspids and molars 
 which goes farther toward simplifying articulation in full dentures 
 than any other one thing of which I know. He has combined the four 
 bicuspids and molars of one side of one jaw into a solid block the 
 occlusal surface of which presents the curves essential to articulation. 
 There are two of these blocks for the upper denture and two for the 
 lower. 
 
 The curves of the occlusal surfaces are designed for the average 
 adaptations, as exhibited in The Simplex Articulator, They may be 
 arranged for any required depth of curve by merely elevating the upper 
 second molars to the desired extent. 
 
 The upper block is properly placed by setting the buccal cusp of 
 the upper first bicuspid and both cusps of the second bicuspid in con- 
 tact with the flat occlusal surface of the lower trial plate. 
 
 The advantages attending the use of these blocks are as follows : 
 
 The teeth can be set in about one-fourth of the time required to 
 set the single teeth. 
 
 J^o curves need be worked out even by the eye. When the bicus- 
 pid cusps touch, as described above, the upper block is in correct posi- 
 tion for automatic articulation. 
 
 The position of each of the teeth in the block is fixed as regards 
 the other posteriors on the same side. 
 
 The lower blocks go to definite places, and require only grinding 
 against the uppers to perfect the articulation. 
 
 The teeth do not change positions during vulcanization. 
 
 The hold of each block on the plate is very strong. 
 
 The interdental spaces on the lingual are filled with porcelain 
 and make a fine finish for the tongue. The buccal sides appear as 
 plain teeth, that is, there is no pink porcelain gum. 
 
 The moulds are the same as in the plain teeth. They present 
 the same deep fossse and sulci, the same high cusps and the same shal- 
 low bite. 
 
 I believe these blocks will become very popular. 
 
 2J8 
 
Fig. 104. 
 Trubyte Molar Blocks. 
 
 219 
 
WAXING PLATES TO FACILITATE PRONUNCIATION. 
 
 Fig. No. 165. 
 
 Try the waxed up dentures in the patient's mouth. Have the 
 patient read aloud and watch the mouth for length of teeth, fulness of 
 lips, etc. 
 
 If the upper plate is hollowed behind the upper incisors as shown 
 on the left in I'igure 1G5, the patient will have difficulty in pronouncing 
 words containing s, st, th, ch, j, x, etc., such as "Peace satisfies the soul." 
 
 Fig. 105. 
 
 The anterior portion of the natural vault is convex behind the upper 
 incisors and facilitates clear pronunciation. This form can be repro- 
 duced by waxing the upper denture to the form shown at the right in 
 Figure 165. 
 
 INVEST L\G THE BICUSPIDS AND MOLAPtS. 
 
 A fine articulation is sometimes destroyed hy a tooth changing 
 place during vulcanizing. The simplest way to prevent this is to use 
 the ]\lo]ar Blocks, which are not likely to change. 
 
 If single teeth are used, the danger of change in position can l)e 
 reduced to a minimum by keeping on hand a supply of sheet copper 
 such as tinners use for water conductors. When the teeth are ready 
 to flask, mal:c a trough of this copper, the bottom of which will lie along 
 the occlusal surfaces of the bicuspids and molars, and a wall of which 
 will extend up along the buccal surfaces. Fill this with Spence's 
 Plaster, mixed thin enough to permit tapping it down to place when 
 inverted on the teeth. Invert on the teeth and tap down to touch all 
 the occlusal surfaces. Be careful not to leave any Spence's plaster on 
 the wax. 
 
 Invest as usual. The teeth should not change positions. 
 
 ARTICULATING THE VULCANIZED DENTURES. 
 
 The vulcanized dentures should be articulated in the mouth by 
 means of articulation paper, or double faced carbon paper, or ordinary 
 carbon paper doubled. 
 
 The patient should be instructed to close the mouth in the position 
 of central occlusion and make slight rubbing movements. Points of 
 undue prominence will be marked on both upper and lower teeth. 
 
 To remove such spots, grind only the one that is out of contact 
 during centred occlusion. If the other is ground, it destroys the 
 occlusion. 
 
 220 
 
Tl;i- liiiiil result. 'I'fctli liiirininiiuiis in f<ini), size niul color, stable in position, and 
 efl!'i<-ni. 
 
 221 
 
PART VIII. 
 
 Illustrations And Descriptions 
 
 Of Teeth 
 And Tables Of Dimensions 
 
GEN^ERAL lA^FORMATION CONCERNING FORMS AND 
 
 MARKINGS. 
 
 The forms in Trubjte teeth are comprised iu three classes, each 
 class comprising the modifications of one typal form. 
 
 Class I comprises all modifications of the square type. 
 
 Class II comprises all modifications of the tapering type. 
 
 Class III comprises all modifications of the ovoid type. 
 
 Each modification is represented by a form, and each form is 
 produced in a series of graded sizes suited to the characteristics of that 
 form. Each size of each form constitutes a separate mould. Each 
 mould is marked with the number of the form and with a letter indi- 
 cating the size. 
 
 Difi'erent letters are used to indicate sizes in the dift'erent classes. 
 In Class I the letters are C-D-E-F-H. In Class II the letters are 
 L-]^I-N-P-R. In Class III they are T-U-W-X-Y. 
 
 The number and letter should always be given. It is then not 
 necessary to name the Class, since the same letters do not appear in two 
 classes. 
 
 There are five forms in Class I, representing five modifications of 
 the long square form. They are numbered l-2-3-4:-5, and the sizes are 
 IC-ID, etc., and 2C-2I), etc. Outlines of the forms in this class are 
 shown on page 85. 
 
 There are four forms in Class II, representing four modifications 
 of the tapering form. They are numbered 1-2-3-4, and the sizes are 
 IL-lM, etc., 2L-2^r, etc. Outlines of the forms in this class are shown 
 on page 87. 
 
 There are four forms in Class III, representing four modifications 
 of the ovoid form. They are numbered 1-2-3-4, and the sizes are 
 IT-IU, etc, 2T-2U, etc. Outlines of this form are shown on page 89, 
 l)iit th(! letters indic;it iiii:' sizes sliould Ik' T-TT-W-X-Y. 
 
 At the time n\' ilic piibliciil ion of ibis book, ( 'biss 111 forms are 
 not far enough coni[)let('d to pcsmiit otlering tliem to tlie profession, 1)ut 
 spaces arc provided toj- tilling in tluiir dim(!nsions when they appear. 
 
 225 
 
FORAt I— Class I. 
 
 This is the long modification of the Square Type, in which the 
 length of the lahial surface of the upper central, exclusive of collar, 
 markedly exceeds the width. 
 
 The upper centrals and laterals are distinguished b}^ nearly paral- 
 lel sides for a considerable distance upward from the incisal edges, and 
 by rather flat approximal curves and wide necks. These curves combine 
 to give the teeth a generally square appearance, though the severe 
 typal form has been so far modified that the angularity and rudeness 
 are lost. 
 
 The upper cuspids present flat curves on the mesial surfaces, but 
 pronounced curvatures of the distal surface. The shoulders of these 
 cuspids are set well forward, enabling the dentist to hide the bicuspids, 
 and secure pleasing effects. The points of the cuspids are cut well back 
 to facilitate articulation with the lower cuspids with a minimum of 
 grinding. 
 
 The collars of the upper and lower anteriors are fairly deep, per- 
 mitting the dentist to imitate recession of the gimis. 
 
 The lower incisors are distinguishable from the lower incisors of 
 the past, by retaining the character of the uppers. The approximal 
 surfaces are nearly parallel for a short distance downward from the 
 incisal edge, then curve inward to medium wide necks. The mesial sur- 
 faces present convex curves, while the distal surfaces exhil)it distinct 
 compound curves which greatly increase the beauty of the teeth. 
 
 The lower cuspids carry out the character seen in the upper cuspids 
 and have their shoulders well to the mesial. This will greatly assist 
 in building up the lower cuspid eminences. 
 
 The upper and lower anterior teeth are shaded as descril)ed on page 
 113. Both sets present natural enamel markings. 
 
 The upper central in each shade is shaded like the sample tooth 
 on the Twentieth Century shade ring, and no other colors appear in 
 the teeth. 
 
 Indicatioxs. Teeth of this form are indicated in faces which 
 are much longer than they are wide, and which exhibit nearly parallel 
 sides and chins of full medium width or more. Such faces are com- 
 mon. Many faces lie on the border line between this form and Form 
 IT in Class I, and also between this form and Form I in Class IT. 
 
 226 
 
Dimensions of Trubyte Teeth 
 
 CLASS I 
 MODIFICATIONS OF THE SQUARE FYPE 
 
 FIVE FORMS IN GRADED SIZES 
 
 WHKX DIMENSIONS AKK NoT CIVKN Tin-: SI/.KS .A.KK IN I'KHrAKATK )N. 
 
 Ai.i, i)imp;nsi()Ns akk in Mii.i.niKTKKs. 
 
 Similar dimensions in plain vulcanite pin teeth; combination sets with individual diatoric 
 posteriors, and combination sets with molar blocks. 
 
 FORM 1. The Long Modification of the Square Type. 
 
 UPPERS 
 
 MoiiUl 
 No. 
 
 I^englh 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anteriors 
 Set up 
 
 width 
 
 iMlll 14 
 
 Set up 
 
 Coinbine<l 
 
 Bite and Shut 
 
 of Central 
 
 width of 
 Central 
 
 IC 
 
 
 
 
 
 
 ID 
 
 9.75 
 
 42 43 
 
 103. 
 
 8. 
 
 7. 
 
 IE 
 
 10.25 
 
 45. 
 
 108. 
 
 9. 
 
 7."> 
 
 IF 
 
 10.75 
 
 46 47 
 
 109-110 
 
 9.5 
 
 8. 
 
 IH 
 
 11.50 
 
 51. 
 
 123 124 
 
 9.5 
 
 8.5 
 
 
 
 LOWERS 
 
 
 
 Mould 
 No. 
 
 I.enjrth 
 
 Central 
 
 Without Collar 
 
 width 
 
 <i anteriors 
 .Set up 
 
 width 
 I-iilI 14 
 Set up 
 
 Couibinetl 
 
 Bite and Shut 
 
 of Central 
 
 width 
 
 ?"our 
 
 lucisoi 
 
 IC 
 
 
 
 
 
 
 ID 
 
 9. 
 
 32.5 
 
 102. 
 
 9. 
 
 21. 
 
 IK 
 
 9. 
 
 36. 
 
 104. 
 
 9. 
 
 22.5 
 
 IF 
 
 9.5 
 
 36. 
 
 106. 
 
 9. 
 
 2:5. 
 
 IH 
 
 10 25 
 
 40. 
 
 115. 
 
 9.5 
 
 25. 
 
 227 
 
FOKM 2— CLASS I. 
 
 This is the medium long modification of the Square Form, in 
 which the length of the labial surface of the upper centrals, exclusive 
 of collar, considerably exceeds the width of that surface, but not to 
 such a degree as in Form I. 
 
 The approximal surfaces of the upper centrals and laterals are not 
 parallel quite so far upward from the incisal edge, as in Form I, and 
 because of the shortness of the teeth, the approximal curves seem more 
 rounding, especially in the small sizes. The necks are medium wide. 
 
 The upper cuspids carry out very well indeed, the character of the 
 centrals and laterals. The shoulders are thrown well to the mesial, 
 and the cutting edges are cut back to facilitate articulation with the 
 lower teeth. 
 
 The lower incisors have the character first seen in the lower in- 
 cisors of Form I, the convex mesial surfaces and the compound curves 
 on the distal surfaces. The labial surfaces of these teeth stand well 
 forward from the collars, enabling the dentist to finish the vulcanite for 
 fine eft'ects. 
 
 Both the upper and lower sets are shaded as described in the fore- 
 going pages. Both sets present natural enamel markings on the labial 
 surfaces. 
 
 Indications. The teeth of this form are indicated in faces 
 slightly longer than they are wide, with fairly straight sides and medium 
 wide chins. Such faces are very common and the various sizes of this 
 form will find extensive use. 
 
 Many faces lie in the border land between this form and Form T 
 in this class, and also between this form and Form II in Class II. In 
 many cases a mould from either form may be suitable. This increases 
 the availability of the moulds by affording suitable teeth of other di- 
 mensions. 
 
 228 
 
CLASS I. 
 FORM 2 — Medium Long. Square. 
 
 TRUBYTE FORM 2 CLASS I 
 SIZES AS MOULDS 2C-2 D-2E-2F-2H 
 
 #iff%^ 
 
 UPPERS 
 
 Mould 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anteriors 
 
 Setup 
 
 Width 
 Full 14 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width of 
 Central 
 
 2 C 
 
 8.50 
 
 42-43 
 
 102-103 
 
 8. 
 
 7. 
 
 2 D 
 
 9.25 
 
 44 
 
 103 
 
 8.5 
 
 7.5 
 
 2 E 
 
 10. 
 
 46-47 
 
 108-109 
 
 9.25 
 
 8. 
 
 2 F 
 
 10.75 
 
 48-49 
 
 110-111 
 
 9.5 
 
 8.25 
 
 2 H 
 
 
 
 
 
 
 LOWERS 
 
 .Mould 
 
 Length 
 
 Width 
 
 width 
 
 Combined 
 
 width 
 
 N'o 
 
 Central 
 
 b anterior.s 
 
 iMlll U 
 
 Bite and Shut 
 
 l'"our 
 
 
 Without Collar 
 
 Set up 
 
 Set up 
 
 of Central 
 
 Incisors 
 
 2 C 
 
 8.5 
 
 33,. 
 
 100 
 
 7.5 
 
 20. 
 
 2 D 
 
 9. 
 
 34. 
 
 101 
 
 9. 
 
 21.5 
 
 2 E 
 
 9. 
 
 36.5 
 
 106 
 
 9. 
 
 23. 
 
 2 F 
 
 10. 
 
 37. 
 
 106 
 
 9.5 
 
 23.5 
 
 2 If 
 
 
 
 
 
 
 229 
 
.... . FOKM 3— CLASS I. 
 
 This is the short modification of the Square. Type, in which the 
 length of tlie hibial surfaces of tlie upper centrals, exclusive of collar, 
 slightly exceeds the width. 
 
 The approxinial surfaces of the upper centrals are, in general, 
 nearly parallel throughout a considerable portion of the length of the 
 tooth, but the sides are so delicately curved as to take away any appear- 
 ance of blockiness which might otherwise result. The necks are wide 
 and the interdental spaces small. The sides of the upper laterals are 
 not quite so nearly parallel as those in the centrals but the generally 
 square character is well carried out. The cuspids are excellently suited 
 to the centrals and laterals, the mesial approximal surfaces being 
 strongly convex, the shoulders prominent and well to the mesial, and the 
 distal angles prominent. 
 
 The lower incisors appear more nearly square than in Forms I 
 and II but they present the same convex curves on the mesial approximal 
 surfaces and somewhat of the same double curve on the distal ap- 
 proximal surfaces. They are admirably suited in character to the upper 
 anteriors. The lower cuspids are very much like the uppers in char- 
 acter, except that the distal angles are not so prominent. 
 
 Both the upper and lower sets are shaded as described in the fore- 
 going pages. They present the enamel markings on the labial surfaces. 
 
 Indicatiojs^s. The teeth of this form are suited for faces which 
 are nearly as wide as tliey are long, and which present nearly parallel 
 sides with flat curves and wide chins. Such faces sometimes present 
 in rather large sizes but it is not believed that teeth of a size larger than 
 3D will be required for any ordinary case. 
 
 230 
 
CLASS I. 
 FORM 3— Short Souare. 
 
 UPPERS 
 
 Mould 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anteriors 
 
 Set up 
 
 Width 
 Full 14 
 Setup 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 width of 
 Central 
 
 3 C 8. 
 3 D ' 8.75 
 
 3 E 
 
 1 
 
 44-45 
 45-46 
 
 105-106 
 108-109 
 
 8. 
 
 8. 
 
 7.75 
 8. 
 
 LOWERS 
 
 Mould 
 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anterior.s 
 
 Set up 
 
 Width 
 Full 11 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width 
 Four 
 
 Incisor.s 
 
 3 C 
 3 D 
 3 E 
 
 7.75 
 
 8.75 
 
 35. 
 36. 
 
 103. 
 
 106. 
 
 8. 
 8.50 
 
 23. 
 
 23. 
 
 231 
 
FORM 4— CLASS I. 
 
 While the majority of faces of the square type present one of the 
 modifications exhibited in Forms 1, 2, 3 or 5, a feminine face some- 
 times presents which differs from these in presenting a square form 
 which is somewhat softened by greater delicacy of outline and yet does 
 not present the type of chin seen in oval faces. 
 
 To permit artistic restorations in faces of this modification. 
 Form 4 has been provided. It is distinguished from Forms 1, 2, 3 by 
 greater convexity of the approximal surfaces, especially on the distal, in- 
 cluding a greater rounding away of the distal incisal angles. The upper 
 laterals are delicate and beautiful in form, and the upper cuspids are 
 rather small as compared with the centrals, being intended to produce 
 the impression of softness and beauty rather than of the rugged strength 
 which characterizes most of the square forms. 
 
 The collars of both upper and lower anteriors are fairly deep and 
 permit the dentist to establish imitations of slightly receding gums. 
 
 The lower incisors are small and dainty but are full of character. 
 The mesial approximal surfaces are gently rounding, and the distal 
 approximal surfaces present the compound curves seen in this type 
 of tooth. The lower cuspids are small and carry out the impression 
 of daintiness given by the upper cuspids. 
 
 I:\^DiCATioNS. For feminine faces in which the cheek curves are 
 more rounding than in the stronger forms illustrated on page Y9, and 
 where the face has a rather dainty appearance, but the chin is fairly 
 wide. Such faces are often small, and the sizes 4C and 4D will be 
 found verv useful in this mould. 
 
 232 
 
CLASS I. 
 FORM 4 — The P'eminink Modification of The Square Type. 
 
 UPPERS 
 
 Mould Length Width Width 
 
 jjo Central 6 anteriors Full 14 
 
 Without Collar Set up Set up 
 
 Combined ^idlh of 
 BiteandShut Cential 
 of Central 
 
 4 C 
 
 4 D 9. 40. 97. 
 
 4 E 
 
 4 F 10.0 45. 107. 
 
 1 
 
 8. 
 9. 
 
 7. 
 8. 
 
 LOWERS 
 
 .Mould 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 b anteriors 
 
 Set up 
 
 width 
 Full 14 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width 
 
 Four 
 
 Incisors 
 
 4 C 
 
 
 
 
 
 
 4 J) 
 
 8. 
 
 29. 
 
 93. 
 
 8. 
 
 18. 
 
 4 i<: 
 
 
 
 
 
 
 4 F 
 
 9. 
 
 33. 
 
 102-103 
 
 S. 
 
 21. 
 
 23.? 
 
FOKM 5 — CLASS I. 
 
 This is the oval modiiication of the square type, formed by a 
 slight modification of the curves of the mesial and distal approximal 
 sides. Where the sides were relatively straight in Forms 1, 2, 3, and 
 rounded into the necks and incisal edges by short curves, the approximal 
 curves in the oval form converge more gradually, forming narrower 
 necks and leaving larger interdental spaces. The widest part of the 
 upper centrals is a little above the incisal edge, and the mesial and 
 distal incisal angles are more rounded than in the first three forms in 
 this class. 
 
 The upper laterals present quite dift'erent characteristics, showing 
 much more of a compound curve on the mesial, and a marked rounding 
 away of the distal incisal angle. Indeed, in this form, the upper 
 laterals contribute a great deal to the appearance which separates the 
 oval form from the more severely square forms. 
 
 The upper cuspids are very much of the same character as the 
 laterals and help to differentiate these anteriors from any other square 
 form. The mesial approximal surfaces show pronounced convex curves 
 with a typical rounding away at the neck. The distal surfaces present 
 very noticeable compound curves. 
 
 The mesial approximal surfaces of the lower incisors present the 
 convex curves of the same character as those seen in the upper anteriors, 
 and strong compound curves on the distal sides. The necks are wide 
 and the interdental spaces small. The lower cuspids present only a 
 trace of the rounding away of the mesial surface seen in the upper 
 cuspids, but this, taken with the compound curve on the distal surfaces, 
 reproduces in a pleasing way the character seen in the upper cuspids. 
 
 Ikdicatioxs. For faces in which the square character has been 
 changed to the oval form by the lengthening of the curves of the cheeks, 
 but in which the chin is medium wide, enough so that the tapering- 
 form is not quite suitable. 
 
 A good many faces lie on the border land between this form and the 
 form illustrated on pages 239 and 241, and in some cases moulds from 
 any of these forms may be suitable. 
 
 234 
 
CLASS I. 
 FORM 5— The Oval Modification ok The Souare Type. 
 
 UPPERS 
 
 Mould 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 aiileriors 
 
 Set up 
 
 Width 
 
 Kull U 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width of 
 Central 
 
 5 C 
 
 5 D 
 5 E 
 5 F 
 5 H 
 
 
 
 
 
 
 LOWERS 
 
 ^lould 
 
 I^eneth 
 
 Width 
 
 Width 
 
 Combined 
 
 Width 
 
 Central 
 
 6 anteriors 
 
 Full 14 
 
 Bite and Shut 
 
 Four 
 
 No. 
 
 Withoul Collar 
 
 Set up 
 
 Set up 
 
 of Central 
 
 Incisors 
 
 5 C 
 
 
 
 
 
 
 5 D 
 
 
 
 
 
 
 5 K 
 
 
 
 
 
 
 5 F 
 
 
 
 
 
 
 5 H 
 
 
 
 
 
 
 235 
 
loirM I ri,A;-S II. 
 
 'I'luf mvi'.t'c. \iit'tii ol ilx- 'I ;ij«;ri/i^ 1,yi"' pf'-'w.'nf^, »» ttt<L' u{>[>c'r ceii- 
 lr(il«, |(»m'l-Jwlly wlnii^lii iipjuoxirrm) nidc^ which converge «o rapidly 
 (Iml- limy vvoiiM Hiiiin-\itiii'.H unati ui iUc tinddUt of the rf>ot, and at other 
 limrrt III, llm ii(«'x III' \\ti'. roof, TIiIh Hcvitnt form Ik not pleaKin^, but 
 wlicii mo(lili<'<| hv ('(iinl)iii;il ion with lh<; H')iiar<! or ovoid typen, presents 
 Muiiif III ilif iiiu I |.l<;i iiiM ;iii(| criVcl ivc I'orinK kiiowu to jjorcelain teeth, 
 
 I'linii I 111 I lie liii-i ;iii(| mr>Hl Hitvi'.vtt itiodificaiion of tlie tapering 
 IVp". Il id i'«'iiiovc(| n hull' riuiii ilic priiiiii iv(; form as may he and lose 
 ijiit nidi'iKiMH whi" h ili;ii liiriii pre -ciit •, liiii il pr<'H(!rv<'H to a remarkable 
 (|('|yt;r(Mi lh(< H(r«'li,"lli .iml i li:ii:ii liT III llif ori.'L! ili;il. 
 
 Tlir II |i|iiir-. iiiiiil MiirfiK cs (d llir ii|»|M'i- rciil r;i I,-, ;irf iicai'ly straiirht, 
 Iml llir ,li"lii iiiii\r\iiv nl ihc iin'siiil siirrjifcs ;iii(| llic just noticeable 
 tjiiiililr ( iii'\r;i III llir (ji'iliil si II' liu-cH, s;iV(' I he Icclli Iroiii hlockijioss. 
 
 riic ii|i|nr l:ilri:il ;iiii| cii^iiiifls nrc ^Irmijiiv coiiV(!X oil llu; mesial 
 Hiii'l'iHt'M mill IkiiIi |iir,tiii nil llir (jishil ,siii'l'iiO(!H the sanK! compound 
 iMll'NTH Hj'cii III llic cciil ni Ih. 'These I'lii'ves iire (|ulte (liller(!iit in 
 ehii I'm let' ri'inii lliuse seen in llie luriiis in ('hiss 111. 
 
 The lower incisoi'M are cil like cha racier wilh lh(( uppers. The 
 iiieiiiiil a |i|iiii\ I ma I surfaces are slii^lillv cmivex and tapcM' to necks luir- 
 immiim:. in wullli willi llie ii|i|m'I's. I'lie dislal ajiproxiinal surfaces are 
 hIIj^IiIIn (imca\e and sa\t' llie leelli ti'imi an appearance ol straiii,htuess. 
 The lower I'lispids are of lik»' forms wilh llie incisors. 
 
 I M'i« \ I 111 \s. These leelli are indicaled for faces which taper by 
 sli'iiiu'hi, liiiii lines lo chins sonielinies of less than uunliuui width. Tn 
 uumv cases ihe tlilTerence in widlli ol' llie chin will delerniinc whotlier 
 ji form from this class or one from the stpiare class is iiidicat(Hl, the 
 wide ihiiis callii\u' lor llie si|nare leelli. 
 
 Tills is one ol the iorms in leelli which is inncli more pleasini;' in 
 ihe monlh ihan oul (d' il. The medinni si/.i's will hi' found Iniruiouiou.^ 
 with the i\ p(* (>f f{\ct* idUMi spoken o( as "The .Vuierican TJusiuess Plan's 
 b'nce," wilh its a]^pt"aranc»' o\ clean ciu sireuiith. 
 
 Tcelh o( ihis f(>rui ai'c likelv lo i^row into i^rcar favor. 'Thcv should 
 be stM w ilhoui ovtM'liippiiiii" o\' the laterals. 
 
 '36 
 
CLASS ir. 
 
 MODIFICATIONS OF TAPERING TYPE 
 FOUR FORMS IN GRADED SIZES 
 
 FORN[ 1 — The Severe Modification of The T.apering Type. 
 
 f 
 
 
 LTPERS 
 
 width 14 
 
 Set up 
 
 IZO. 
 122. 
 
 Bite and Shut 
 of Central 
 
 9.5 
 9.5 
 
 Width of 
 
 Central 
 
 LOWERS 
 
 Mould 
 
 No. 
 
 
 L 
 
 
 M 
 
 
 N 
 
 
 r 
 
 
 R 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 atitcriors 
 Set up 
 
 42. 
 44. 
 
 Width 14 Combined 
 <^t iiT» Bite an.i shut 
 ^' "P of Central 
 
 Width 
 
 Four 
 Incisors 
 
 ' 10. 
 10. 
 
 I 
 
 112. 8.5 
 lU. 10. 
 
 26. 
 27. 
 
 237 
 
FORM 2 — CLASS II. 
 
 This is the second modihcatioii of the Tapering Type and is a 
 little fnrther removed from the severity of the typal form than Form 1. 
 The approximal snrfaces of the upper centrals are niore convex and 
 turn apart more at the necks. The distal approximal snrfaces show 
 more of a componnd cnrve and altogether the teeth are less straight. 
 
 The laterals and cnspids carry out the character of the centrals 
 so that the appearance of the npper anteriors is even better expressed 
 bv all of the teeth than in some of the other forms. 
 
 The lower incisors do not show quite as much departure from the 
 straight form as do the uppers, but they serve as beautiful and charac- 
 teristic bases for the uppers. The mesial approximal surfaces are con- 
 vex, but do not turn quite so much apart as in the upper teeth. The 
 distal surfaces exhibit the same compound curve as in the uppers. The 
 necks are fairly wide. 
 
 The character of the lower cuspids is identical with that of the 
 incisors except that the distal angle is more pronounced. 
 
 IxDiCATioxs. This form is particularly suited for masculine faces 
 of less strength than those requiring Form 1 and for some feminine 
 faces of the tapering type. 
 
 The beauty of these teeth is increased by setting the upper laterals 
 to overlap the centrals when conditions warrant it. 
 
 238 
 
CLASS II. 
 FORM 2— Second Modification of Tapering Type. 
 
 UPPERS 
 
 Mould 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 fi an tenors 
 
 set u\> 
 
 width 14 
 
 Set up 
 
 Combined „.-j^, <• 
 
 Hite and Shut A\idth of 
 
 of Central Central 
 
 L 
 
 2 :m 
 
 2 N 
 
 2 P 
 
 R 
 
 8.75 
 9.75 
 
 10.50 
 
 41. 
 44. 
 
 47-48 
 
 103. 
 106. 
 111. 
 
 8. 7. 
 
 8. 7.5 
 
 9. 8. 
 
 LOWERS 
 
 
 I.enjrth 
 
 width 
 
 width 14 
 
 Combined 
 
 width 
 
 
 Ceutral 
 
 (i anteriors 
 
 Set u]) 
 
 ;!ite and Sliut 
 
 I'our 
 
 
 Williout Collar 
 
 .Set up 
 
 
 ol Central 
 
 lucisors 
 
 L 
 
 
 
 
 
 
 2 M 
 
 8. 
 
 33. 
 
 99-100 
 
 8. 
 
 20. 
 
 2 N 
 
 9. 
 
 34. 
 
 102. 
 
 9. 
 
 21-22 
 
 2 V 
 
 10. 
 
 37. 
 
 108. 
 
 9.5 
 
 23-24 
 
 R 
 
 
 
 
 
 
 239 
 
FOKM 3 — CLASS II. 
 
 This form is the third modi tication of the severe typal form, and 
 is somewhat softer in outline than Form 2. The mesial approximal 
 surfaces of the upper centrals and laterals show convex curves, but 
 these surfaces are not so straight up and down in the incisal thirds and 
 turn more widely apart at the necks, leaving wider interdental spaces. 
 
 The distal surfaces do not show the compound curves of Form 2 but 
 are gentlv convex from cutting edges to necks. 
 
 The curves in the mesial surfaces of the cuspids are quite different 
 from those in Form 2, being more nearly straight but with a slight 
 tendency toward a double curve. 
 
 The lower anteriors are much like those in Form 2, with the dif- 
 ference that the necks are narrower and the interdental spaces are wider. 
 The cuspids are straighter in character than in Form 2. 
 
 Indications. This form and I'\>rm -t are particularly suited to 
 feminine faces of the tapering type. These faces are often very beauti- 
 ful. They have been selected by many great masters as the subjects of 
 their paintings, and they have always commanded admiration. 
 
 This form will be found suitable for many such faces, as well as 
 some male faces. 
 
 The upper laterals may well be set to lap the centrals. 
 
 240 
 
CLASS II. 
 FORM 3 — The Third Modification of Tapering Type. 
 
 UPPERS 
 
 Mould 
 No. 
 
 LeiiK-th 
 
 Central 
 
 Without Collar 
 
 Width 
 
 b anteriors 
 Set up 
 
 width 14 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 width of 
 Central 
 
 L 
 
 
 
 
 
 
 :m 
 
 
 
 
 
 
 3 N 
 
 9.75 
 
 45. 
 
 105. 
 
 8. 
 
 8. 
 
 3 P 
 
 10.50 
 
 50. 
 
 124. 
 
 8.5 
 
 8.5 
 
 R 
 
 
 
 
 
 
 LOWERS 
 
 Mould 
 No. 
 
 l.eiiBrth 
 Central 
 
 With 
 
 (j anteriors 
 
 width 14 
 
 Combined 
 Bite and Shut 
 
 width 
 Four 
 
 Without Collar 
 
 Set up 
 
 
 of Central 
 
 Incisors 
 
 Iv 
 
 
 
 
 
 
 M 
 
 
 
 
 
 
 3 N 
 
 92 
 
 36. 
 
 103. 
 
 9. 
 
 22. 
 
 3 P 
 
 92 
 
 38. 
 
 114. 
 
 8. 
 
 25. 
 
 R 
 
 
 
 
 
 
 241 
 
FORM 4 — CLASS II. 
 
 Tlie softest modification of the tapering type and exliibiting the 
 greatest modification of the original form by combinations with Types 
 1 and 3. 
 
 The mesial aj)proximal surfaces of the upper centrals are decidedly 
 convex and begin to separate at the incisal edges. They turn apart 
 quite a distance and leave a rather wide interdental space. The distal 
 approximal surfaces exhibit marked compound curves. 
 
 The laterals show much more strongly than the centrals the modi- 
 fying influences of the other types of teeth. Both approximal surfaces 
 are convex, and the compound curve seen on the distal of the centrals is 
 not in evidence. The cuspids are more like the centrals in character. 
 
 The lower incisors express strongly the character seen in the upper 
 centrals, the compound curve on the distal approximal surfaces giving 
 them much character. The lower cuspids are rather straight but have 
 well defined distal angles. 
 
 Ijstdications. This form is well suited for feminine faces which 
 taper from eyes to chin by soft curves, often quite rounding. It is par- 
 ticularly suited to the character of faces seen in illustrations and in 
 great paintings and typical for beauty. The laterals may be set to lap 
 the upper centrals slightly which increases the beauty. 
 
 242 
 
CLASS II. 
 
 Form 4. — The Fourth and Softest Modification of the 
 Tapering Type. 
 
 TRUBYTE FORM 4 CLASS H 
 SIZES AS MOULDS 4L-4M-4N-4P-4R 
 
 ..jnim 
 
 UPPERS 
 
 Mould 
 
 Length 
 Central 
 
 Width 
 6 anteriors 
 
 Width 14 
 
 Combined 
 Bite and Shut 
 
 Width of 
 
 No. 
 
 Without Collar 
 
 Set up 
 
 Set np 
 
 of Central 
 
 
 4 L . 
 
 
 
 
 
 
 4 M 
 
 S 75 
 
 41. 
 
 9S-99 
 
 9. 
 
 8. 
 
 4 X 
 
 9.75 
 
 44-45 
 
 106. 
 
 
 
 4 P 
 
 
 
 
 
 
 4 R 
 
 
 
 
 
 
 LOWERS 
 
 
 Length 
 
 Width 
 
 
 Combined 
 
 Width 
 
 
 Central 
 
 6 anteriors 
 
 
 Bile and Shut 
 
 l'"our 
 
 
 Without Collar 
 
 Set up 
 
 Set up 
 
 of Central 
 
 Incisors 
 
 4 L 
 
 
 
 
 
 
 4 M 
 
 9. 
 
 31.5 
 
 95. 
 
 9.5 
 
 19.5 
 
 4 N 
 
 9. 
 
 35. 
 
 103. 
 
 9.5 
 
 11. 
 
 4 I' 
 
 
 
 
 
 
 4 R 
 
 
 1 
 
 
 
 
 243 
 
Form 1 — Class III. 
 
 When the description is published in The Dental Digest 
 it may be placed here. 
 
 244 
 
CLASS III. 
 
 MODIFICATIONS OF THE OVOID TYPE 
 
 FOUR FORMS IN GRADED SIZES 
 
 FORM 1 — The Severe Modification of The Ovoid Type. 
 
 UPPERS 
 
 Mould 
 
 No. 
 
 Length 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anteriors 
 
 Set up 
 
 Width 
 Full U 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width of 
 Central 
 
 1 T 
 
 1 U 
 
 1 W 
 
 1 X 
 
 1 Y 
 
 LOWERS 
 
 
 Length 
 
 Width 
 
 Widtli 
 
 Combined 
 
 Width 
 
 Mould 
 
 Central 
 
 6 anteriors 
 
 luill 14 
 
 Hiteand Slmt 
 
 I''our 
 
 No. 
 
 Without Collar 
 
 Set up 
 
 Set up 
 
 of Central 
 
 Incisors 
 
 1 T 
 
 
 
 
 
 
 1 U 
 
 
 
 
 
 
 1 W 
 
 
 
 
 
 
 1 X 
 
 
 
 
 
 
 1 Y 
 
 
 
 
 
 
 245 
 
Form 2 — Class III. 
 
 When the description is published in The Dental Digest 
 it may be placed here. 
 
 246 
 
CLASS III. 
 FORM 2 — TiiK Skcoxd Modii icatiox of The Ovoid Type. 
 
 UPPERS 
 
 Mould 
 
 No. 
 
 I^enietli 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anteriors 
 
 Setup 
 
 Width 14 
 Setup 
 
 Coiiil>iiie<l 
 
 liiteaiid Shut 
 
 of Ceiitralv 
 
 Width of 
 Central 
 
 2 T 
 2 U 
 2 W 
 2 X 
 
 2 Y 
 
 
 
 
 . 
 
 
 LOWERS 
 
 ., t< Length Width | „r:Atu ^A 
 
 Mould Central 6 anteriors Width 14 
 
 ^"- Without Collar Setup Setup 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width 
 
 Four 
 
 InciHJjrs 
 
 2 T 
 2 U 
 2 W 
 2 X 
 2 Y 
 
 
 
 
 247 
 
Form 3 — Class III. 
 
 When the description is published in The Dental Digest 
 it may be placed here. 
 
 248 
 
CLASS III. 
 FORM 3 — The Third Modification of The Ovoid Type. 
 
 UPPERS 
 
 Mould 
 No. 
 
 Length 
 
 Central 
 
 Without Collar 
 
 Width 
 
 6 anteriors 
 
 Setup 
 
 Width 14 
 Setup 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width of 
 Central 
 
 3 T 
 3 U 
 3 W 
 3 X 
 3 Y 
 
 
 
 
 
 
 LOWERS 
 
 -, ,, Lengfth 
 Mould 1 Central 
 
 N°- 1 Without Collar 
 
 Width 
 
 6 anteriors 
 
 .Set up 
 
 Width 14 
 Set up 
 
 Combined 
 
 Bite and Shut 
 
 of Central 
 
 Width 
 
 Four 
 
 Incisors 
 
 3 T 
 • 3 U 
 3 W 
 3 X 
 3 Y 
 
 
 
 
 
 
 249 
 
Form 4 — Class III. 
 
 When the description is published in The Dental Digest 
 it may be placed here. 
 
 250 
 
COLUMBIA UNIVERSITY LIBRARIES 
 
 This book is due on the date indicated below, or at the 
 expiration of a definite period after the date of borrowing, as 
 provided by the rules of the Library or by special arrange- 
 ment with the Librarian in charge. 
 
 DATE BORROWED 
 
 DATE DUE 
 
 DATE BORROWED 
 
 DATE DUE 
 
 
 
 
 
 
 'rJ/IW rt r 1 
 
 
 
 
 "" 2 X i 
 
 Ub 
 
 
 - 
 
 |an15M6H^ 
 
 I 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 .- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 C28(|I40mIOO 
 
 
 
 
RK656 
 Glapp 
 
 G531 
 
 
 ^^{iU 
 
 JtalSMdRAV 
 
ill'' fe'^'ll