GREENE BROTHERS' COURSE IN PLATE-WORK IN THREE LECTURES '\ . » CT THi ^ O LIBRARIES S HEALTH SCIENCES LIBRARY Digitized by tine Internet Arciiive in 2010 witii funding from Columbia University Libraries http://www.archive.org/details/greenebrothersclOOgree Peter Thomas Greene ( 1828—1909 ) Jacob Wesley Greene ( 1839 ) Gratitude in inemoriam To the memory of our elder l)r()ther and pre- ceptor, the late Peter tbomas Greene of New Albany. Indiana, this little work i^ gratefully dedicated. Dr. P. T. first recognized the practical ad- vantage of the shallow-tray non-tissue-strain- ing principle in impression-taking, and was the first to introduce it. He was an ardent worker in the early evolu- tion of what since has been developed into the present established Greene Brothers' Advance- Test System of Plate-work. To his helpful, courageous persistency, in the face of ignorance, suspicion, jealousy, and envy (difficulties especially attending old- fashioned secret teaching), the new System owes its founding ; and progressive plate- workers owe, and will duly bestow, their sin- cere gratitude. Our brother began life near Corydon, Harri- son County, Indiana, in IS'?8, and departed from his earthly home in New .Vlbany, to the many loved ones of his youth and later years, ('// the other side, in February, 1900. He served industriously in his calling, as a progressive worker and instructor. o\er half a century. jACoi; \\'. GrilEXK. ChiV.ieothe. Mo.. July i, JQio. REVISED EDITION, 1914 GREENE BROTHERS' CLINICAL COURSE IN DENTAL PROSTHESIS IN THREE PRINTED LECTURES NEW AND ADVANCE-TEST METHODS In Impression, Articulation, Occlusion Roofless Dentures, Refits and Renewals BY JACOB W. GREENE Chillicothe, Mo. Author of "Dental Information for the psople" — 1870. $1.00 Patentee of Greene's Ready-Made Metal Models — 1908 Inventor of Greene's Removable- Handle Impression and Bite Tray 1910 Inventor of Weighted Lower Bite-Plate; Tongue Rest Flanges ("Jokers") for Lower Dentures; Real Anatomical Bites for difficult Cases; Greene's Pressometer, for Measuring Stress, in Bites: Short- Cut and Quick-Step Methods in Plate-Work, and Greene's Occlusion Retainer to Do Away With All After-Grinding and Greene's Metal Roof Reinforcer to Prevent Elxtra Thickness of Plates. Copyright. 1910 By Jacob W. Greene Chillicothe, Mo. Copyright. 1914 By Detroit Dental Manufacturing Co. Detroit, Mich. PUBLISHED BY DETROIT DENTAL MANUFACTURING CO. DETROIT, MICHIGAN CONTENTS LECTURE I. Upper Mouth Only. — Reasons for Improved Methods. - — Old Ways Unreliable. — Test Impressions. — Impressions of All Sorts of Mouths. — All Kinds of Impression Mate- rials — Plaster, Modeling Composition, Bee's-Wax, and Combinations of Them. — All About Roofless Plates, Re- fits, and Renewals from Old Plates, by the Greene Test Methods. — Short-cut and Quick-step Upper Plates. — Un- reliability of Plaster Models and How The\' Cause Fail- ures. — Instructions in Use of the Greene Xon-changeable, Ready-made ]\Ietal ^lodels in ^"ulcalli/,intl; and Swaging. — And so forth. LECTURE II. Lower Mouth Only. — Principles and Methods of First Lecture, as Applied to Lower Cases ; with Others Special to the Lower. — Partial Impressions with Leaning Teeth and Bell-shaped Crowns. — Why Lower Dentures Are So Generally Unsatisfactory and How to Correct the Diffi- culties; by Muscle-trimming. Conforming, Shot-weighting and Tongue-})ower Methods, and Consequent Suction. — And so on. LECTURE III. The Bite, and All that follows, to the Finished Case. — Only the Tired-rest Position of the Jaws Reliable. — The "Xo-bite" Gives this Position. — How to Take It and Test It. — Bite ]Must Give Four Essential Points. — (a) The Show-length of the Teeth; (/->) Their In-and-Out Stand- ing; (f) Their Occlusion; and (r/) The Strain on the Tis- sues. — A Simple Pressometer. — Bites for Lower Partials and All About Them. — Some Old Troublesome Problems Solved. — Brand-new Occlusion Scheme for Difficult, "Crip- pled" Cases. — Each ^loutli Its Own Automatic Articulator in the Finis. — Ethics in Plate-work. — Interesting and Instructive Lecture to Patient Before Dismissal — And much more. IX Dextal Prosthesis. vil CAPTIONS AND SUB-HEADINGS Ix»ir.\Tix(; Thk.mes and Methods LECTURE NUMBER ONE Ui'i'EFt Dentures. I'AGE Printed Notes for Students' Riferenee f) Class Close Around the Table 11 First Hour of First Three-Hour Lesson 1"2 \^'hat W'v ^^'ant to Do in Taking; an Imjiression U! All Moviiig Tissues Must Move Air-Tight Hi An Appro.xiniate Correctable Ini])ression Hi Fit Tray to .Mouth 17 Two Ways of F'itting Tray IS The Fitted Metal Tray ]<) Upper Trays Illustrated — Old and New -21 How to Take Correctable Impression ■2'2 Two Ways to Take Correctable Impression -22 Student's Correctable Impression 22 Practitioner's Apjjroximate Inii)ression ( I'irst Ste))). . . 23 Practitioner's Test for Fit 2') Suppose It Doesn't Center-Test 26 Trim It Approximately (Seccnid Steji) 26 To Get Length of Plate in a Soft Mouth -28 To Find Length of Plate Over a Hard Palate 29 Correct Roof to Test-Fit (Third Step) :5() Correct the Rim to Muscles (F'ourth Stej)) 32 Relief-JVitJiniit-Lrdh-, the Modtling-Compouiul Impres- sion Pass-Word 32 ^'erv-Edging. or .Muscle-Trimming 33 To Especially Fit Particular Muscles 34 Conform Com))ouiul to Soft Part ( Fifth .Step) 36 VIII Greene Brothers' Clinical Course PAGE Conform ("Post-Dam") Back Palate (Sixth Step)... 39 The Essential Art in Handling Modeling Compound. . . 41 Uniting Details 4-2 Test tlie Completed Impression 43 Stop, Think and Reason 43 If Impression "Swallows Down" 44 About Nausea 4o Make Model on Tested Impression 45 Modeling-Compound Impressions. Old and New Way Illustrated, Figures 4 and 5 4(i How to Make the Model 48 To Separate Model from Impression 49 Don't Let Impression Change 49 Metal vs. Plaster Models oO Greene's Non-Changeable IModel S\'stem 51 Modeling-Compound Impressions in Difficult Cases .... 53 Soft, Flabby Alveolar Ridge with Hard Roof 54 Vienna Paste for Reducing Soft Gums 55 Flabby Gums in Front and Hard on Sides 57 A Valuable Review 58 Roofless Denture 59 Instructions to Patients 6l Extra Supports to Roofless Plates 6l Retention of Roofless Plates . 62 Partial Upper Impressions 62 I>eaning Teetli and Bell-Shajn-d Crowns 63 Recapitulation on Coring 64 Plaster Impressions for Partial Plates 6 !• To Test a Plaster Impression 67 Plaster Impressions in ^Modeling-Compound Trays 68 To Take Test-Impressions in Plaster 69 Pass-Word for the Greene ]\Iethod of Plaster Impres- sions 71 "\^'hy Plaster at All" for Impressions 73 A Quick-Step Denture Method 74 Typical Upper Impression in Plaster — Old and New Way Illustrated, Figures 7 and 8 75 IX Dental Prosthesis. ix PAGE Refitting of Plates 77 Temporary Refits with "Perfection" Comjjoiind Wa- ters . . ". 78 Permanent Refit with Vulcanite 79 To Refit with Plaster Impression by the Pass-Word Method 82 Common Old-Fashioned Refit of Rubber Plates 83 To Reproduce New Plates from Old Ones 83 The Greene Ready-Made Models in Refits 80 Precaution in Refitting; and Renewing; Plates 86 Greene Brothers' Clinical Course CAPTIONS AND SUB-HEADINGS Jndh .\Tix(; Themes and Methods. LECTURE NUMBER TWO Lower Dentures PAGE First: A Modeling-Compound Impression in Detail... 87 To Avoid Straining the ^Muscles [}\ Typical Lower Trays^ Old and Xew. Figures. 10. 11. 12 9'' Take a Correctable Lnpression J)! Practitioner's Correctable Lnjiression — Step No. 1 . . . . [)() Step Xo. ^ in Lower Lnpression 101 Step Xo. :i in Lower Impression 101 Step XO. 1 in Lower Impression 103 Step Xo. ,") in Lower Impression lOt Step Xo. 6 in Lower Impression lOo Step X'o. 7 in Lower Impression 106 Step Xo. 8 in I>ower Impression 108 Step Xo. 9 in Lower Impression 109 Step Xo. 10 in Lower Impression 110 A Lower Plaster Impression Ill Partial Lower Impression 1 l.S ^Modeling-Compound Impression with Leaning Teeth and Bell-Shaped Crowns Ill Coring-Out for Under-Cut Im])ressions .,115 Old-Time Inijirovemeiits in All- Plaster Lower Impres- sions 117 Old Way and Xew Way Modeling-Compound Im^Jres- sions illustrated, Figures 13, 14 and 15 l'-21 To Refit a Vulcanite Lower Plate Temporarily 122 To Refit a \'ulcanite Plate Permanentlv 123 IN Dental Prosthesis. XI PAGE Renewal of Rubber Plates from Old Ones 126 Weight in Lower Dentures 128 To Shot- Weight an Old Vulcanite Plate 129 To Shot- Weight a Xew Vulcanite Plate 129 To Strengthen Lower Plate 130 Mixed Lower Plates 131 Swaging Lower Plates 132 Cast Aluminum Plates 133 Refitting Lower Metal Plates with Vulcanite 133 Substitution of Heavy Cast Plates in Place of \'ul- canite or Celluloid 134 To Refit and Renew a Cast Plate with the Same Mate- rial 135 XU Greexe Brothers' Clinical Course CAPTIONS AND SUB-HEADINGS IxDicATixG Themes axd Methods. LECTURE NUMBER THREE PAGE Articulation. Occlusion. Bite. etc.. etc 136' Now for the "Bite" 141 Absurdity of a Common Motionary Bite 14^ Tired Relaxation the Natural Position of the Jaw US What Do We Expect from a Bite.^ lil The "Biscuit." or "Mush," or "Squash" Bite 145 The Rim Bite 145 The Greene Improved and Perfected Rim Bite 146 Bite for a Full Upper-and-Lower Set 146 Ujjper ^Nlodel First 147 Trim for Fullness of Upper Lip and Teeth 147 Trim Bite-Plate for Length of Lpper Teeth 148 Heavy Lower Bite-Plates 149 Trim Lower Bite-Rim for Length of Lower Teeth 149 The Outstanding of the Lower Teeth 150 The Tired-Rest Test-Bite, or "No-Bite" 151 Re-inspect No-Bite for Feature Test 153 Greene Tired-Rest Bite ("No-Bite") Illustrated. Fig- ure 16 153 Fourth Point, or Pressure Feature, in a Bite 154 A Simple, Practical Pressometer 154 How to Use the Greene Pressometer in a Strain Test. . 155 Unequal Pressure Sometimes Needed in a Bite 157 Verifying the No-Bite 158 Matliematical Test of the No-Bite 158 The Third Still-Jaw Test l6() IN Dental Prosthesis. xill PAGE Greene Pressometer Illustrated. Figure 17 16() Transfer Xo-Bite to the Articulator l6l Anatomical Movement on the Xo-Bite l6l A "Crijjple" Mouth Its Own Articulator in tlie Fi)ii.s. . . l6'2 Correct Bites Till They Do Test l64 Firm Articulator Important iG.'j Articulator in Most Common Use l66 To Fix Lower Model on Articulator idS Base-Plates l69 The Base-Plate 170 Setting Up Teeth on Base-Plate 171 Trying Teeth in the Mouth 173 Importance of Stress 17^ Side Remarks— Prosthetic Quackery 175 Weighted Modeling-Compound Bite-Rim 177 Still :More About the "Joker" 179 Another Reason for the Joker 179 The Joker a Xew Idea 1 80 The Lateral, or "Sheep-Bite." Movement 181 The Common Old Plain-Line Articulator Inij^roved for Anatomic Work 183 The Forward Bite Mivement 185 Each Mouth Its Own Articulator in the Finis Fur- ther Described 185 Class Requests Difficult "Cripple"-Case ArticuLation Again and Further Explained 186 Xew Way to Take Test X'o-Bite. in Xo-Handle Bite- Trays 189 Improvement in Biscuit Bites 190 Flasking the Case 191 Packing and Vulcanizing 192 How to Vulcanize 193 Dishonesty in Rubl)er Plates I94 Last Finishing Care in Articulation I96 A Still Finer Last Grinding Touch 197 Better Defer Final Adjustment 198 Instructions to Wearer of Artificial Teeth 198 XIV Greene Brothers' Clinical Course PAGE No-Bite of a Plain Upper Case 201 The Non-Lateral, Minimum Short-Bite, or No-Bite, Described Again, by Request 203 The Full Upper No-Bite Test 201 Transfer the No-Bite to Articulator 205 Pink Rubber and Gum Sections 207 Bites in Scattering Cases 207 Pressometer in Upper Cases 208 Partial Posterior Lower Bite 208 The New Common Sense Occlusion 213 Every Mouth Its Own Articulator 213 Occlusion Retainers Illustrated 21(1 Greene's Occlusion Retainers 217 Full Double Set 218 Common Sense Occlusion Shown in Mouth 219 IX Dental Prosthesis. xv INDEX PAGE Upper Trays Illustrated — Old and New Figures 1, 2. 3. 29 Muscle-Trimming, or Very Edging 3'! \ ery-Edging. or Muscle-Trimming 33 Length of Upper Plate 28. 29. 30 Post-Damming Rear of Plate 39 Practitioner's Method of Fitting Tray to Mouth. 17. 18. 19 Conforming 3(). 37. 38 "Pass-^^'ord" Method of Plaster Impression .. .6'9. 7<). 71 Test for Pass-Word Imj^ression 71 Fit Tray to Upper Mouth 17. 18. 19 Fit Tray to Lower Mouth 91 . 92 Lower Trays Illustrated — Old Style and Impro\fd. Figures 10, 1 1 , 1 2 93 Correctable Lower Modeling-Compound Impression — Student's Method [H To Separate Impressions from Approximate Model. . . . 9-' Coring Out Under-Cuts in Lower Impressions 9-5 Practitioner's Correctable Lower Impression 9G Remove Teeth from Old Plate 8 t Cloth in Packing 193 Refitting Plates with Vulcanite 79 Mtreuri;il-Tin Paste for Reuio\ing Tin-Foil from \'ul- canite Plates 82 A Quick-Step Denture 71 Greene's Quick-Step Denture 7i, 7.). 7() Tracing-on Modeling Com])ound witli Kerr Tracing- Sticks 17 Greene's Occlusion Hrtaiiurs Illustrated 2l6 GREENE BROTHERS' CLINIC LECTURE COURSE IN PLATE- WORK. WHY IN PRINT. While this Course is hmited to plate-work, it embraces most of the important points in that specialty; and on lines of original, new and improved methods. Also it is more par- ticularly meant for vulcanite and similar work; of wliich probably 90 per cent, of all plates are now made. It is given as a private course of instruc- tion for practical utility, and more especially for active practitioners. Xo "Jionors" are offered, save that for im- provcmeni in this most difficult and vmcertain branch of dentistry. Yet in self-defense, against deception and fraudulent pretensions, we give our certificate to show one lias taken our Course directly from central authority. Tliougii we liave been instructing more or less from the incipiency of the work fifteen years ago, when we gave but an hour (then mostly on impressions), up through its devel- o])ment to an eight to ten-hour Course, we have not been giving it publicity till 1907. So there are yet but a few schools that have it familiar enough to enable its thorough teach- ing to inexperienced students. From now on we expect to give it to all willing to pay rea- sonably for our services. As justification for charging for our time, it is necessary only to mention that we have en- tirely given up our ])rivate ])ractice to devote 2 Greexe Brothers' Clinical Course our aged efforts to the new Private Instruction Business for a livelihood. About teaching it: After many years' exper- imentation and gradual development, our prac- tical Course now embraces a System, including some advance test methods, where the work is exact and technical. Hence, the imparting of it to others is not a little matter to be "told" on the sidc'walk; nor even well taught at a distance, in hurried, public clinics, by an inexperi- enced novice. To our amusement, dentists sometimes tell us they "already know" our methods because someone has "told" them what they are. The fact is: to perfectly teach the Greene System (or any other) one must fully understand its basic principles, have expert experience, and be familiar with practical teaching requirements. To this end our business plan has been to instruct individuals, classes, and local societies, in limited numbers, in their towns and cities; usually by pre-arrangement. When wanted, we go also to colleges and instruct classes of advanced students, in groups of ten or less. At no distant time we hope to see many of the plate-work instructors in the schools familiar enough to themselves fully teach their students in the new ways. The trouble is that so many schools employ inexperienced men and boy in- structors on glory'pay in this important branch of dentistry. The need of our Course is fully emphasied M'hen eminent prosthesists publicly assert that "Good, artistic plate* work is fast becoming a lost art." Years ago, even up into the '80s, a goodly share of most dentists' practice consisted of plate* IX Dental Prosthesis. 3 Avork. There was so much of it done, and so com- paratively few dentists to do it, that many be- came experts, even in the old guess-work methods. So the average grade of the out^put was de- cidently above that of now'a«times; now, when most of the old "mechanical dentists' are gone, and the voung men disdain the "dirtv, uncertain work." And so it is that the once attractive, artistic specialty has been discarded by both the boys and the "best men" and turned over to commer- cial (mal)])ractice. And such practice obtains to the extent that half the plate=wearers look hke silly and vicious ghosts grinning through moonshine. It was the prideful effort of the old-timers to rather hide art and imitate Nature. So, in the more professional (we called it "mechanical") past, dentists far more seldom allowed patients to dictate, and "j)ick out teeth to suit themselves"; which they are wont to do ^\ith unquestioned commercial license. Sure enough the old=timers have reason to conclude that "artistic plate-work is fast becom- ing a lost art." 3Iuch of it is being aone in "false=tooth factories" by boys who have never studied dentistry at all, and who never get to see the disfigured faces through which their glossy- white pearls must grin - shine so hideously. How many dentists (commercial pro])rietors) boastfully tell us: "Z don't do platenvork my- self. / simply take the impressions and bites and have the main work done." What a pro- fessio rial co n ce])tlon ! Two gobs of material — im])ression and bite — hurriedly thrust into the moutli and jerked out; then turned over to the laboratory boys and girls, strangers in the case — "sight miseen"! 4 Greene Brothers' Clinical Course The "toosbusj^" dentist (and there are many of them), who can neither do his own plate' work x^ersonally nor have it done under his own supervision, giving due study to each case on its own pecuhar merits, should turn it over to the legit unate specialist, who can handle such important practice consistently and properly. It is one of the purposes of the Greene Brothers' Course to encourage and train special- ists to care for this most difficult work of the dental art=science. For years we have been urged to give our lecture « demonstrations in printed form, and teach our methods in that more convenient and less expensive way. But for several reasons we have refrained from doing so till now. We have feared the difficulty of teaching fine f)oints in art by mail. AVe feared failures might bring our System into disrepute before fully established, and ruin at least our business. But now we feel differently. After a mid* teen years of persistent work, and since we have reached national attention by publicly lectur- ing and demonstrating to local and State and Xational meetings, with fully satisfactory re- ception, we are persuaded to yield. Since we have the backing of thousands of testimonials of satisfaction and earnest recom- mendations from our student ])ractitioners of all classes and grades in half of the States in the Union, we no longer fear that a few possible failures to understand, or a few^ technical criti- cisms, or even kickers, would seriously harm our "traveling dental school." Then, as there is but one of us left and as he is doing business on borrowed time (this 1910), we have consented to this publication. In so doing we have first in mind those who have taken, or may take, our Course from us IX Dental Prosthesis. 5 in our regular way, but who may not have caught onto, or may not catch onto, all of our numerous new pointers; also those who may have forgotten, or may forget, some of them before opportunity for practice. To such the printed Course can't fail to prove a most valuable reference; even though in it we have abridged many of our verbal repetitions and cut out some of our odd but convincing illustra- tions, used in the lectureswork. Second, we have in mind the thousands who will have their attention called to our work, but could never get it from the central source in any other way than this. I might add that, though a student of our methods through these printed lectures will un- fortunately miss the inspiration of personality that always goes with all verbal teaching (and to M'hich, maybe, too much is sometimes accred- ited in our class^talks) , he will nevertheless get our most important inventions, discoveries and new practical pointers, if he will think. We have tried to be clear and comprehensive, and hence, in some sense, to some readers, may be uselessly detailing. To steer clear of literary pretense, when I know I 'm not "in it," I have herein held much to the colloquial and self^idiomatic of my verhcd Course. Having scratched all this out from steno- graphic notes, taken from my offhand talks in class'Work, I may have edited carelessly, if not ignorantly, as to elegance of diction. With my sole aim to eliminate some of the guess-work and uncertainty from "mechanical dentistry" and to help restore the "lost art," I may have thought (maybe known) less of rhetoric than of work. Maybe I should apologize for even A\'orse — for coining some non^dictionarial vocabulary. 6 Greene Brothers' Clinical Course Well, that's been done before; otherwise we 'd have no "occlusion," nor "articulation," applica- ble to artificial teeth. Pardon my independence. If, with all my acknowledged shortcomings, I have been helpful, in a measure, to the work- ing dentists and to the wearers of artificial teeth, my purpose has been attained and my chronic ambition gratified. Jacob W. Greene. CRITICS, DON'T! ''Ohj that mine enemy would write a hook!" DoN^T imagine tliis a text^book, please. It 's merely a series of offhand, "show=me" talks in j)rint; by an old'and=childish "tooth^dentist" — three'scoresand^ten, ten more, and then some. Dox^T tantalize while I weep for its literary Aveakness! It was: Write this, or keep on talk- ing — three to six hours a day. I 'm tired. DoN^T criticise my repetition. I 've learned that most dentists need the like in their studies. DoN^T object to this mail Course. My "itin- erant dental school" is getting too old to trek. DoN^T wink-smile at my impromptu vocab- ulary. It 's the answer to my prayer for inspira- tion, meet for the occasion. DoN^T accuse me of competition with (otlier) dental colleges. I 'm only setting up and finish- ing their goods, shipped out in the knock-down. DoN^T blame me for not having my sub- themes and pointers in more systematic order. I was incarnated in Old Hoosier, in the early days, in the woods, among the whoo-owls, on Friday night, in the dark of the moon, out of order, against my better judgment. DoN^T accuse me of egotism. I 'm unassum- ing. I 'm patient. I can listen by the hour to IX Dental Prosthesis. dentists repeating how they do things (by the old guess=ways) . Dox^T^ above all, criticise because you can't understand me. "The carnal ( dento * carnal ) mind cannot discern spiritual (dento-spiritual) things." J. W. G. INTRODUCTORY. While the Greene Brothers' Prosthetic Course is limited to plate'work, it takes in about all of that much=neglected brancli; and along new lines and advance test methods. By test methods we mean such as enable us to know by actual test in advance what the re- sultant outcome will be. To illustrate my meaning I will suppose you have, for instance, a plate that exactly suits you and its wearer. If you should mold and du])li- cate another one from it, you would know, in ad- vance, just how the new one would be. Bear in mind, I say, if you duplicate the tested plate. Xow, it is proposed to give you a whole course, amounting to a System, of advance=test plate^work methods, covering about all of tlie imjoortant ])oints in the specialty. THREE SEPARATE LECTURES. The Course is generally given in three sep- arate clinic lecture*demonstrations, wherein the principles are taught by reason and analogy, and the ap])lication by "showing" (from Missouri). Incidentally it becomes necessary to sliow, likewise by reason and ajDplication, that some, and not a few, of the old and commonly used methods are not only defective and faulty, but absolutely erroneous and absurd. 8 Grekxe Brothers' Clinical Course Sometimes it becomes necessary to show the defection of an old road bridge, and to remove it before substitutino- a better one in its ])lace. And again sometimes it 's best to remove the old structure by section and piece and substitute corresponding parts of the new one, working the old and new in together, into one reconstruction. OUR SYSTEM A GENERAL RECONSTRUCTION. In a comprehensive sense the Greene Broth- ers' System is a reconstruction of plate=work methods. If in plate^work the impressions and models and "bites" and the like can be compared to the abutments and pillars and arches of a railroad bridge, our method may be taken as a somewhat radical departure reconstruction. I hope to make these truths appear plain as I proceed systematically in my analogies and jDractical demonstrations. THE FIRST SECTION, OR "DEGREE." The first one of the three sections of our Course, here to be considered, pertains to the upper mouth onJif. And here I '11 mention, as an indicating prelude, the leading subjects to be dealt with in this lesson; the minor ones to come in at opportune times and places, as we proceed. First — Test Impbessiox; full and partial; in all types of cases, easy and difficult ones ; with all the different sorts of materials in common use, as modeling composition, plaster, bee's-wax, and combinations of them. Second — The whole matter of roofless dent- ures, in clear mouths and also over "anchors" (worn^off teeth) ; and partial cases. Third — Test=methods of refitting plates, both temporarily or permanently; and renewing, or IN Dextal Prosthesis. 9 duplicating, new ones from old ones, still main- taining occlusion and position of teeth, or chang- ing the same if desired. Fourth — The making of dentures by short- cut, quick methods, whereby a fast worker can make a perfectly fitting {pre-tested) plate of vulcanite or celluloid in from twosand-ashalf to three hours, from start to finish. These and more are included in our first sec- tion, or "degree,' of the three of our Course. However, in case of large classes we some- times divide these sections so as to give the full Course in four or more lessons, as may mutually suit our time and convenience. PRINTED NOTES FOR STUDENTS. We have here printed notes on the leading and more important points; one list of them for each of the tlu'ce sections, or lectures. Each individual of the class is entitled to these slips, which notes will be explained by me, in detail, in the clinic, and then read aloud im- mediately following by someone of the class. The demonstration and tlie reading together will impress the ])oints on your minds, and tlie preserved notes will be your references in the future, if necessary.* After the reading of each note any member of the class can ask for any further explanation he desires on the points gone over. T5ut we '11 have no time to listen to criticisms^ discussions, nor to how you, or others, do these things, until the lecture is over. But I do want you to ask pertinent questions, and even ask for repetitions until you fully under- stand each point; then you '11 ])robably have no criticisms to offer. *This printed work will now supplant the note references. 10 Greexe Brothers' Clixical Course Should you ask questions out of time and place, which eagerly interested students are apt to do, I will then inform you that the answer will come in later, in its order. At the close of each lecture we'll review, if desired; and then again at the close of the Course. I am no less desirous that you fully catch^on than you yourselves are ; for I live wholl}^ by what my students say of me and of my work. As an incentive to my effort to please and to benefit I expect to earn, and seldom ever fail to get, the best recommendation my students can write. (And I '11 mention by way of parenthesis I have over a thousand such testimonials, on their own letter'heads, that I "point to with pride." Scores of these, as some of you have seen, are from the "best men" of highest national stand- ing- )"^ jUp to January, 1914, about two thousand. IX Dextal Prosthesis. 11 LECTURE NUMBER ONE. (Class close around the table.) Doctors: You will now all come up close enough to the clinic table to not only hear my whys, but see XJcJiat I do, and distinctly hot^ I do things. For some of the points I will make are as "fine" as anytliing you do at your operating^ chair, or with your blow^pipe. And some things here must be done almost as quickly as a snap= shot negative is taken. But now don't get scared at this statement, for I 'm not going to require of you anything more difficult, or more j)articular, than many things you do in almost every other operation you perform. But I shall require of you the same pains and exactness of manipulation in plate-work tliat you exercise, for nicety and suc- cess, in other branches. The patient who pays your fee for a set of teeth is just as much entitled to the best you can do as the one who pays you for a fine crown, bridge or filling. (Pardon my digression off into professional ethics — you are my i)atients for the time.) Before we get through the course, you '11 concede I owe no apology for these last suggestive remarks. A CLASS STUDENT AS PATIENT. I will now need one of you with a liberal mouth and no mustache, at mv left side, whom I '11 honor as "^Nladam." Xow, Madam, I want you to sec me wash my hands and scrub my nails with clean water, soap and a brnsli, before they go into your mouth. As 12 Greene Brothers' Clinical Coi'rse a nice madam, of course, you have no disagreea- ble oral habit ! Now, ]Madam Jones, while yoii will be my main patient, I'll have an eye single, and a different finger, for the mouths of the rest of the class, opportunely. (A spontaneous lahi' lingua crusade against the "weed" all around.) You can all best realize these touches jirst in your own mouths; later on, for practice, in the hosjjitable mouths of your mothers-in-law. FIRST HOUR OF FIRST LESSON. I will mention here that the jirst hour of this threeshour lesson is spent in the general manipulation and improved metliods of hand- ling and working modeling composition, in tak- ing impression; first in full cases, and then in partial ones — easy and difficult ones included. Strange and unreasonable as it may seem, the very inventors of modeling impression ma- terial don't conceive of its real possibilities; hence, I may add, only a few produce an article tdth needed possibilities. Usually it is condemned by the "best men"; and well it may be, as a tchole, if worked by the old methods in common practice. Xine*tenths of all "brands" are faulty, even by the im- proved methods; and all of them practically worthless by the old ways, and in the common spreadsmouth trays — excepting in simple and easy cases. But with the right material, used in the right handling, composition material is not only the best material, but about all that could be desired. If this sounds "fishy," just wait and see! With it we can take an approximate or "cor- rectable" impression, and adapt and conform IX Dextal Prosthesis. 13 it in detail to the different tissues and muscles of the mouth, both stationary and movable, un- til each place is fitted and tested to a certainty of correctness. And then as a finished, completed result we can absolutely test as to its fit as a ichole under the practical movements of the mouth gener- ally; and then easily duj^licate a denture from it that must stand the movements the tested imj)ression stood. That is to say: if in a modeling'Compound impression we find that any muscular move- ment will throw it down, or up, we can change and correct it, when we know how. Really, however, it makes little difference of what material an impression is made, just so it stands the test of the movements. The practical question is: What material can be made to conform to the moving nuiscles, giv- ing them room to move in freely, and yet press with valve-like tightness, giving relief tcithout leak? These are the essential qualities of any ma- terial for teivt impressions; we trust no others. Xow, it is for me to sliow you what should be done, how to do it, and what to do it with. WHAT WE WANT TO DO IN TAKING AN IMPRESSION. In taking an inqiression, the main three points to be attained are: (a) the correct height and lengtli of tlie expectant })late; (b) about an equal strain on the stationary hard and the soft parts of the covered mouth, at about the pres- sure it is to be worn; then (c) room for tlie movable i)arts to move in and still be valve- like tight. That is to say, again, relief-without* leak in muscular motion. 14' Greene Brothers' Clinical Course If taken at a much harder pressure than the plate is to be worn, the tissues will be dis- torted, and, of course, the plate will not fit when the parts are not strained, but must come back to their normal position. It looks like everybody ought to think of this, but only a few do. Let me close my left hand and call the back part of it, including my knuckles, a mouth, with hard and soft j)arts. The knuckles are the hard parts and between the knuckles the soft parts. Now^ contrary to the general teaching, you always get the impression of the hard, station- ary parts right. No matter what material you use or pressure you give, you get the impres- sion of the hard parts about right — right in proportion to their solidity. You think your plates rest too hard on the hard parts, and are told to scrape them there and "relieve" them. Absurd, for thej^ are right, in proportion to the hardness under them. If anything is wrong, it is on the soft parts, or else the movable hard parts; which exception we '11 consider in a fe^^- minutes. See me press with my right index finger be- tween the knuckles on my left fist. The tissue is soft and it yields. Just so do the soft parts in the mouth give when you take an impression, with either modeling compound or thick plas- ter. But the knucldes don't y\e\d — excepting that of the left little finger. Now for the impression, supposing it to be of my hand. To get it correct we must make this soft tissue yield just enough to give us a pressure about equal with that on the knuckles, at about the strain the denture is to be worn. If we press too hard on the soft parts and strain them too much, thev will rebound when IX Dextal Prosthesis. 15 we cease the pressure, and will lift the impres- sion (or plate) off the hard parts; in which case there would be air under it, over the hard parts. And, of course, the air there would, to some extent, offset and neutralize the air pressure from the opposite (upper) side. In other words, our "suction" (atmospheric weight) would be lessened. But, on the other hand, if we press too light- ly on the soft parts and don't make them give any at all, the impression (or plate) will rest so loosely on them as to admit of air there; and again we 'd have lessened atmospheric pressure. Atmosplieric pressure and "suction" are syn- onymous terms. Whenever there is any air un- der a plate, however rarefied it may be, the "sticktion" will be lessened accordingly. So, when you don't press the soft parts up with enough strain, you say your plate rests too hard on the hard places. This isn't ex- actly true — only relatively true, since the bear- ing is correct on the hard parts, and lacking elsewhere. "Perfect adaptation" means a similar strain on the hard and soft places; but atmospheric pressure, or "suction," is what holds an upper plate to its place — unless clasps or other clap* trap means are used. I '11 merely remark here, a little premature- ly, that I '11 show you later on in this lesson that it takes surprisingly little "suction" to hold a plate u]) if it has no strain to throw it loose. But ecpialized strain on the hard and soft parts isn't all, nor even the most important thing, to be obtained in this matter. We have movable parts — muscles and tissues — that must be accommodated, as vou here see on and around 16 Greene Brothers' Clinical Course my little finger's moving knuckle, as I tighten and loosen my hand's grip. Xow, in a plate, and consequently in our impression, we must provide for this movement; or it will lift it up, if a lower one, or work it loose, if an upper one. Tliis is usually done (old way), or rather at- tempted to be done, by scraping the plate after it is made; or by trimming the impression with a knife — both by guess. The moving muscle, or other moving part, must not only have room to move in, but it must move, as we say, valve=tight, air-tight. Otherwise air w411 get under it, and away goes your "suction," your atmospheric hold. ALL MOVING TISSUES MUST MOVE AIR=TIGHT. Xow% doctors, get yourselves fully impressed with this essential fact in plate^work. But who can file and scrape impressions, models, and plates, so a muscle can work freely and yet be air'tight? Or, as we say, valve=tight, similar to a piston in a tube syringe? "Guess*work is as good as any wlien it hits." But how many can guess out, or guess ofT. room for a straining muscle to move with valve^tight pressure? Only the experienced few, and then only in easy cases. We have a way of making this air=tight working room without file or scraper; and, too, without guessing. This is done by a method of nmscle^trim- ming, soon now to be demonstrated, in this lesson. AN APPROXIMATE, CORRECTABLE IMPRESSION. We first take an approxiamte, "correctable" impression; which is but a modeling^compound IX Dental Prosthesis. 17 tray within a metallic tray. By "correctable" I mean one that has none of the metal tray in sight. Then we transform this correctable impres- sion, or tray, into an accm*ately fitting tcs-t im- pression; at some detail when necessary. FIT METAL TRAY TO THE MOUTH. To avoid straining the tissues and distort- ing the mouth to be covered, we use only shal- low, or low=rimmed, metal trays — never deep ones. These trays are always lower on rim and shorter in length than our finished plate is to be; and never steep in the roof, lest we strain the back palate with metal and then lack ma- terial for correcting the strain. Our metal trays are low, also, in order that we may not strain the lip=andscheek tissues; and further that we may have material above the rim which can be reduced or extended in transforming the modeling = composition tray into an impression. Should you ever need a deeper metal tray (very seldom), you can trace^on an edge of mod- eling compound from a round stick of the same material as the impression, heated over a spirit lani]) — here shown. This traced^on rim is hard when you want it hard and wdll be soft when so needed. For- merly I used common sealing=wax to ])uild up the edges of my metal trays; but these (Kerr's "Perfection"*) sticks are better, from the fact that these rims become a part of the finished impression. I know of 1)11 otluT tlwit we'll tr;icf so wi-U a-> this Kerr's "Perfection." [2] 18 Greexe Brothers' Clixkal Course TWO WAYS TO FIT TRAY. For this we have two methods: the student's method and the practitioner's method. I '11 first give you the student's way. It is to first take a common, hurried impression "any old way," and make a hurried model from it; and then fit a tray to this a]j]jroximate model, in- stead of fitting it to the mouth itself; the lat- ter being the practitioner's method. The student's method is, in fact, a good one for even the most experienced, who are willing to take a little extra time, say five minutes, to first get this approximate plaster model. Indeed, it is the preferable way, and becomes the settled one with many of my students in practice. Well, I have a model here before me. We '11 suppose it to have been made by some one of you from a hurried common imi^ression — ^^or, as for that, from a "good" impression ("good," but untested and not knozcn to be good). AVe '11 take an old, soft=metal tray and cut it off at the heel so as to be a little shorter than we think our coming plate should be. judging from the model; and then we '11 trim it down at the sides and in front, so as not to be quite as high as we think our plate should be. AVe '11 thus make it seemingly about a full one-eighth of an inch too short and too shallow all around. And we '11 fiatten it down so as to have very little elevation in the center. If we get its rim an eighth of an inch really too low. no harm done; for our impression material will become a rim of itself. Then ^\e want the metal tray a little larger than oiu- model (or mouth), so as to work loose- ly over it; say with a scant eighth of an inch play all around it. IX Dextal Prosthesis. 19 It is easier, at least for a novice, to fit a metal tray to a model than to a mouth. Ex- perienced practitioners can readily fit it to the latter. But whichever way you do it, fit your tray thus, to within an eighth of an inch of the gums all around; and always shy of the attacli- hig muscles of the li]) and cheek, so the metal won't strain them in the least. Don't let your metal tray run up high he- hind the tuberosities so as to strain the tissues there. Bear in mind, 1 repeat, i/our metal tray mustn't .strain the tissues ani/ichere; espeeiall// not the muscular tissues. (Stick a pin in that essential fact.) After long effort. 1 liave succeeded in getting some Greene-Method trays made on purpose for those who may learn their advantage. There are for the present ten in a set; and so shallow in depth, and otherwise so shaped, as to re- quire a minimum of change. They are manu- factured by the Detroit Dental ^Manufacturing Coni]^any, Detroit. Mich. While you can cut your old trays down and shape them, as I show you, yf)u can get more appropriate new ones. Ours have removable handles, the advantages to be shown later on. THE FITTED METAL TRAY. Xow you have fitted your metal tray, either to the approximate model or to the mouth it- self, in a way to leave space*room for your com- pound to hide it (the tray) when your correct- able impression is first taken. That is. the im- pression material must cover the metal trays all over. The metal can't be mani])ulated: the material can be — one reason for l()w=riinined travs. ■20 Greene Brothers" Ci.ixical Course Be sure your tray either has holes through it or else is well smeared with aetually adher- ing compound before you place that for the impression on it, to insure sticking safely. And I '11 here remark in advance: Be especially care- ful in fastening impressions to metal trays in partial cases. IX Dkxtal Prosthesis. 21 Fig. 1. Fis Fig. 1. — Average deep tray before eiit down and fitted to the mouth. Its high rim would distort tlie tissues. All trimming of plates from impressions in it must l)e In' unreliable file-guess-work. Fig. 2. — Same tray after cut down and fitted to the mouth. Can be deepened, if necessary, witli modeling compound traced from Kerr's tracing-sticks. Then the impression rim can be accurately muscle-trimmed. Fig. 3. Handle can be removed for nuiscle-trimminf impression fills out the lips and cheeks. and to show how 22 Greexe Brothers' Clixical Course NOW TAKE YOUR CORRECTABLE IMPRESSION. This I A\ill ti^^t illustrate in detail. Then, when you understand it in detail. I "11 unite these details as we "d do it in a practical op- eration. You "11 combine as many details as your case and your experience may warrant. But first learn the principles iu dissection and practice them in detail, till you can safely unite them. TWO METHODS OF TAKING CORRECTABLE IMPRESSIONS. We also teach two methods of taking a cor- rectable imjDression : (a) The student's method, and (h) The practitioner's method. The practitioner can often use the student's method to advantage, but the novice in impression=taking would best learn by the stu- dent's nit'thod. STUDENT'S CORRECTABLE IMPRESSION. Take your no^\• lifted tray, with its low rim and short rear, and take an impression of the same model you fitted the tray to. This will give you an approximate impression with a mar- gin of material above the metal rim and behind the metal tray. It may be so lacking as not to deserve the name ''impression." It '11 be merely a modeling^composition trai/. It will, however, be your student's correctable impression. To take this correctable impression of the model, you first dust it with flour of soapstone. so the impression won't stick to it. "And don't ijou forget it!" To separate them, you first chill the im- pression a little; then pull it away a little bit IX De.vtal Prosthesis. 23 from the iiKKlel at the heel, or tuberosity. Then quick=dip in cold water to let it (the water) in between the impression and model, and very qiiich'If/ hard^squeeze them back together, to re- store shape to the impression; for it probably sprung some in the })artial removal. Then take the model out of the impression and cool it thoroughly. Should you neglect to pull the im- pression a little away from the model while it is yet warm in the interior, as shown, vou may have diificulty in getting it off when cold. The next thing would be to transform this .correctable impression, or compound trai/. into a perfect tested impression. But before we do it. we '11 take up (First Step.) THE PRACTITIONER'S APPROXIMATE IMPRESSION. So now we "11 stop to take a similar cor- rectable impression by the practitioner's (cut* short) method. Then we 11 lit each of these approximate impressions to the mouth, in about the same manner. To take a correctable impression from the mouth (practitioner's way), instead of from the approximate model ( students way > . place the "Perfection" compound in a small pan of water with rubber dam under it to prevent sticking. Heat is some, but not hot enough to scald your lingers. \Vitli your hands and fingers well wet with warm water roll the material into a ball: place it in a tray. linger=press or fashion it to approxi- mately fit the mouth, but cone'.shaped is eenter. with full=high rim all around. The cone=shape is to insure its striking the center of the mouth first and scattering out- 2t Greene Brothers' Clixical Course wardly; a matter of especial importance in deep arches. All impressions of all materials must scatter from the center out^^•ardlv. With your material well shaped, now pass it back and forth, laterally, over a small hand* spirit*lamp flame, to soften the surface to a semi^flowing consistency, not quite hot enough to burn your fingers at a test=touch. Ahcai/s have your fingers zcet with warm water. Tell your patient it 's quite warm, but not hot enough to burn. Don't forget this precaution. Xow, with your left arm around your pa- tient's head (her head forward rather than back- ward) and the long finger of your right hand in the under-center of the tray, push upward gently, with an up=tension, wave*like motion : an up'ward spring-like pressure, mind you. Push light] If, for impressions should be taken at about the strain plates are to be worn. (This point is worth repeating in your prayer for suc- cess. ) Technically speaking the proper strain would be just what the patient would use in sucking the impression up. If the roof of the mouth is deep, pull forward a little while you are playing upward, in order to strike the front palate right=angle*ward; for modelingscomposition impressions should be taken at about right angles at all points, as well as to about the normal sucking plate=pressure. When you have it pushed to place, hold it steadily until you reach around to the right side of the face and with the index finger of the left hand adroitly flip up the squashed material that overlaps the rim of the metal tray there. Then remove your right-hand central finger, aforesaid, and dextrously change off to your IX Dental Pkostiiesis. 25 left'lmnd middle finger, in place of the right- hand one. Hold as before while you reach around and flip up the left overlapping ledge with the right*hand index flnger. (Don't get hands and Angers mixed up. ) I mean quickly push the compountl up above the edge of the tray all around; but not tightly against the gums — for reason given later on. Xow, right aicaij, while the material is still soft, tell i)atient — and show her how — to work the rim of the im])ression down by hp*and*cheek motion. By prompt movement of your own lips you will prompt her. (And you must do this familiarly yourself to impress your patient to do it. Get before a mirror and practice.) Hold up impression flrmlv with vour right- hand middle flnger while patient gets a quick move on her and obeys orders. This lip=and=cheek movement gives you the approximate height of the impression — not the exact height. Xow to cool it. Again change to left flnger and hold while with your right hand you reach to your cup of cold water and get a little sponge, about the size of a small ))lack walnut, and hold it, ice=cold, up against the under roof of the metal tray for a full half*minute, to cool the im])ression. PRACTITIONERRS PARTIAL TEST FOR FIT. When cold, let go the tray. If the impres- sion stays in place ( without any muscular move- ment to dislodge it), that proves it flts the roof and alveolar ridge; all the fit you want note. You know it flts there, because it stays up without fltting anywhere else. You 've never pressed it to the gums on the side nor at the back palate; hence the stick must be at the 26 Greene Brothers' Clinical Course center and on the ridge — just what you want for the present. This is the iesi for the center and ridge fit. And I '11 assure j^ou that if you do this, as I 've told you and here shown you, you '11 not fail to get this center'fit once in fifty times. That is, to repeat: by coning*up your material in the center, warming it to a half-flowing condition over a spirit flame and pressing it up by wave* motion, at normal wearing plate=pressure, suction pressure. Now you 've taken your correctable impres- sion by the practitioner's method; and you have about the same results as by the student's meth- od, onlii that you have a tested fit to the roof and ridge, which the student liasn't. SUPPOSE IT DOESN'T CENTER-TEST. But now, doctors, for convenience of in- struction, we '11 suppose that once in a while we mat/ fail to get tliis i"oof=fit by the practi- tioner's method. We '11 then first get the ex- act length which the plate is to })e at the back palate, and proceed to correct the roof and ridge till it does test^fit. ^lark this point in our work: AVe make no roof correction until we first get the exact length of our impression at the rear, Xor do ^ye do both, the correction and getting the length, at the same step into the mouth, {Seeond Step.) TRIM IT APPROXIMATELY. We have before us our correctable impres- sion. In this case it fits nowhere correctly yet. Now, our second step is to complete its ap- proximate trimming. IX Dental Prosthesis. 27 Its rim has already been trimmed aj^prox- imately, as to height, by the H]J=and*cheek mo- tion of our patient, "^ladam"' (usually one of the class) ; but its sides are thicker than we "11 \\ant them to be in our next move, so we 11 thin them down a little. I will touch the sides slightly to this man- agea})le liand=lamp Hame and shave them down with this sharp poeket=knife to about three times the tliickness we 'd want an ordinary finislied plate to be. We ^^arm it \'ery slightly to cut more easily. Xext, we '11 cut the impression oft* at the rear, leaving it a little longer than we think our finished plate sliould be; say at least an eighth of an inch too long. If it weren't that long, we (1 take a tracing=stick of Kerr's "Per- fection" material (same as the rest of the im- pression ) and trace^on to wanted length, ( Here the fine art of tracing-on is shown objectively to tile dee]) interest of the class.) But now, before we show how to get the CiVact lengtli of a plate at tlie rear, we must understand what length it should be. TJiat is one of the most important matters in phite= work — if a roof is to be left at all. In many mouths a roof isn't at all necessary; and in some actually detrimental. But where used, the cwact CiVtott is often a very close ])oint to make. ' In some mouths even an eighth of an inch or less would cause sticktion, or ])revent it; then again, in othei's we have a latitude of a quarter or third of an inch margin to go on. AVhat we want is to reach onto the stationary soft parts and yet not onto the movable soft parts. If we don't get onto the yieldable soft and press it up, our plate will tip down behind eas- 28 Greene Brothers' Clinical Course ily. And if we get onto the movable soft, it may move and push the plate down; or, at least, cause "gagging." Xow, can we make that fine line of demai'k- ation between the stationary soft and the mov- able soft tissues at the rear of our impression? If we can't, we may fail. TO GET LENGTH OF PLATE IN A SOFT MOUTH. If the mouth is what we call a soft one (no hard palate), we find this line with close pre- cision by the ordinary swallowing movement That is, we thin down the impression from the under side ( it piu'posely being a little longer than the metal tray) until the edge is, say, an eighth of an inch or so thick, and a little bit longer than we think a plate should be in that mouth. Then we warm this thin, projecting edge at the side of the little spirit=lamp flame till it will yield readily to the touch of our finger, but not biu'n it. Then we slip the impression into the mouth quickly and have patient bite down on our fin- ger and promptly swallow a time or two. She has to bite down on something to enable her to a good effort. Now she has swallowed boldly. We take the impression out and find the rear of it turned down, as far as the moving parts moved; and ordy that far. We chill it in cold water and trim off to where it turns down. We may do this a sec- ond, or even a third time, if necessary to make sure of the all=important point. This procedure will give us the proper length of the plate ninety or more times in a hundred, if done rightly. And in the other ten or less times in a hundred the failure would show up IX Dental Prosthesis. 29 when we made our final test of finished im- pression; which we can then correct. (The process is here shown closely to each one in the class. ) TO FIND LENGTH FOR PLATE OVER A HARD PALATE. The method just described is for a mouth Mith a soft roof. We have an easier and quick- er way of finding the length of an impression (or plate) in a mouth with a hard palate. Doctors, you have never taken an impres- sion of a hard'palate mouth that didn't show just wjiere the hard reached to. You can gen- erally see it quite plainly. And such an im- pression always tells you itself just where to cut it off; at least, where not to cut it off. Tliat it will not do to cut it off on the hard part will hear repeating — ^^Several times if necessary. It 'd ihcn easily ti]) down, not having a valve*like pressure. Cut it off at least one==eighth of an inch back behind the limit of the hard part; even a quar- ter of an inch is often advisable. Just so you don't let it reach onto the movable soft part; in which case it would "swallow do\Mi," or "gag" badly. To repeat the ride: Reach onto the station- ary soft part without encroaching onto the mov- aJ)lc soft part. This valve=j)ressure=line demark- ation is always an eightli of an inch wide — generally more. Pretty soon I '11 show you how I make the essential valve ])ressure thereon. And a little })rematurely 1 "11 here mention that we must reach the soft tissue and make this coming valve^pressure fit extend clear around on the plate^tosbe — l)ehind the tuberosities and all. 30 Greexe Brothers' Clinical Course We must have an equalized'pressure fit all over it and, additionally, a valve^pressure fit all around the edges. We must, by detail when necessary, transform the non-fitting, correctable impression wholly into a correct one and test it finally to knotc that it is correct everywhere. W^e now have the rules for finding the length of an impression (consequently plate) for either a hard or soft palate. We class the medium with a soft palate. A hard one is where yon can see in the impression of any ^^I'oper ma- terial just where the hard reaches to. {Third Step.) CORRECT ROOF TO TEST=FIT. We now have the approximate height of rim and true length of impression. However, if at any point the rim is lacking, we "W just trace-on as much as is needed, as I have shown you. This tracing-on of additional material will be more frequently required beliind tuberosities than anywhere else, because in some mouths you can't, in the first place, get your finger up there in the mouth to push it up. We '11 first trace^on the required material and then approximately place it, with wet fin- gers. We '11 adjust it correctly when we so treat the rest of the rim. Xow we are ready to make tlie correct jit to the roof and ridge, which shoidd have been accomplished when we first took oiu* correct- able impression, and which will l)e accomplished ninety-five times in a hundred if done as shown you. Well, this roof correction is quickly and easily made. We have here a common tin^cup with a spout like that of a teapot, near its top, that will pour IX Dental Prosthesis. SI a stream about the size of a ten52>eiiny nail. From it we iJoui- h(jt water into the impression until it fills up to within an eighth of an inch from the top. We pour on and on, the hot water running off at the heel. We '11 not heat quite to the top of the rim, however; the patient's lips would then turn it over the wrong way when we 'd insert it in her mouth. We '11 get the center as soft as we can ^^•ith- out burning the mouth. And here the Kerr "Perfection" has rare possibilities. We quicldif insert it and immediately wa\'e=2)ress lightltf — quickh', for haste here is absolutely essential to success. To simx)ly see this is to learn //oic; but with slow people sufficient quickness may have to be acquired by practice. Xow, the question simply is: Can //ou do this quickly enoughs If not, why, then not at all. Xo physical stupidity nor poke^andsgO' easiness will fit in here. If you can, you '11 seldom fail in the first effort. But the hot'pot pouring and other efforts must be repeated until the impression will stand a roof^fit test; /. r.. hang there snugly, with no muscular movement to loosen it. Take notice, now, if we have made much change in the impression in this "equalizing" work: we may find a little bit of a roll of com- pound showing up where the hot and cold points met on the inside of the rim. If so, we '11 scrape it off down even, before we forget it. While this roof^correcting step is very sel- dom necessary in the ])ractiti(mer's method, it is very fre(|uently needed with the student's method. It de])ends on whether or not the coni- ])ouii(l is coned=u]) iji the center, softened thor- .'52 Greene Brothers' Clin'ical Coirse oughly, and pushed up with right motion at a proper angle and due strain. I 'd hke to both whisper and "holler" these essentials in the ears of all plate*making dentists. I could save them so much trouble. (Fourth Step.) CORRECT RIM TO MUSCLES. This is to get the precise height of the plate' rim everyxicliere, including behind tuberosity, and especially to get a correct fit to the moving, ■straining tissues. I don't mean to get for them merely relief from strain, but a sort of accommodating pres- sure to them, with ample room for air=tight movement. We christen the gratifying result RELIEF=WITHOUT=LEAK — THE PERFECTION COMPOUND IMPRESSION "PASS=WORD." We accomplish the precisi(ni in part by a system of muscle=trimming on sensitized edges. We take our approximately trimmed impression, warm the edge of the rim slightly all around, including tuberosities, and pinch it up a little. This })urposely brings it up a little too high and somewhat thin at its very top. This extra high rim we norc warm quite soft to a very shallow depth, insert it in the mouth, and with quick, positive movements of the lips and cheeks w^ork it down to the proper height, to fit the moving muscles. This I give you as an advance, liurried pre- lude to what we do. Xext I '11 ".shore" ijoii. (From ^Missouri.) Xow watch me closely. By the side of this little hand'Spirit*lamp flame I warm this IX Dental Prosthesis. 33 pinched*up edge (one side at a time in many cases) very soft to the depth of about an eighth of an inch. Now I '11 slip it into the mouth very quicldy, and have patient promjitly make all possible movements of her lips and cheeks that she 'd make in wearing a plate. I usually do this one side at a time. Take notice: (a) very soft; (b) to a very shallow depth; and (c) all done very quickly. Three "very" a. "Stick a pin" in to hold these three "very"s! Well, to impress you I '11 baptise this stunt in New River and name it VERY'EDGING OR MUSCLE -TRIM- MING, So I ha^'e trimmed the rim of the impres- sion, hence the plate, too, by muscle movement. Everj^ tissue, hard and soft, has cut its way into this "very" soft rim (over a hard under stratum) and has room for free pressure movement. Sometimes this has to be repeated, and j^ar- ticular points especially warmed, to get the trimming exact. But persistence is sure to bring accurate results. "Quick work!' Yes, it is quick work. And, by the way, you can, by this very = edging process, trim an impression (hence the plate) more than ten times quicker than you could file ' trim a plate, not considering the incom- parably greater accuracy in favor of muscle' trimming. Each one of you will liave to ])ractice and get the move on your own face, to show your patients. You can't merely tell all what to do. Some must be "shown." 13) 34 Greene Brothers' Clixical Course Then, once in a while, you nia\' have to train a patient — not only to act, but to act promptly j before you attempt the practical action of her face. If one attempts to joke and say and do funny things, just look stolid and don't smile, but frown at her "monkeying." Give her to mi- derstand that you are in earnest, and she soon M'ill be. Until you become familiar with this part of the work you may have to "very'cdge" one side at a time, always entering into the mouth on the opposite side from the softened rim. This to prevent the cheek from malspressing the softened edge. Be careful to soften proj)erly behind tuber- osities. Tliere the muscles, sometimes stringy, will press down onto the soft material and do their own trimming, without much, if any, straining motion. In your hurry don't forget this })oint. behnid and around the "heel^knobs." TO ESPECIALLY FIT PARTICULAR MUSCLES. As a matter of importance, I '11 here again repeat: If anywhere, at any time, you should see on your partially "very=edged" rim indica- tions of muscle strain, just re* warm that par- ticular spot "very shallow" at the side of your spirit flame, or, better, with a mouth blow=pipe, and hurry it into the mouth and have patient work that muscle promptly. If she is too slow, assist her motion with your fingers. But better first train lier to her own movement, whenever you can. ^Vhile attendhig to special parts, don't for- get the upper freenum. You '11 be surprised at both the quickness and accuracy of results. Unless individual muscles need special attention. IX Dental Prosthesis. 35 you can accurately trim an impression (conse- quently the plate) in a few seconds. Bear in mind: AVhen you musclc'trim a rim*edge, it is, with rare exceptions, left high enough to reach beyond tlie hard parts onto the soft and yieldable tissues. Only on such you can get valve^pressure fits. (Here in the class Course we show the very* edging process, in minute detail, on our own jjractical plate, in our own mouth; altvays to the gratifying surprise of the old ' way file- trimmers. ) Someone asks: "How much should this be done in a given case?" Why, iust till the or- dinary and natural movements of the cheek and lips fail to cut any deeper into the "very softened" material. But, doctors, don't forget this "new thought," that you 've probably never heard of before ; cer- tainly never in print. There are some mouths where cheek=and*lip motion isn't sufficient, even when properly done. It is sometimes neces- sary to further and additionally warm the im- pression down into the groove that covers the ridge and tuberosities, from about the second bicuspid back; and then have patient bite down onto your fingers, or her fingers, or on some com- pound, placed for the purpose on the under-side of the tray — on both sides at once. This is to provide in your denture for strain made by the biting muscles and must be done by biting down instead of pressing up. But all this will come up more plainly in our second lesson when dealing Avitli the massiter muscles. When a plate is trimmed to stand tlie ordi- nary movements of the mouth and face, the M'earer will soon learn to avoid extraordinary 36 Greene Brothers' Clinical Course ones, or even to safely make them, in practical use. (Fifth Step.) CONFORM COMPOUND TO SOFT PARTS. Your impression reaches up onto the yield- able tissues, on which you are to make an equahzed valve'pressure strain against the in- ner side of the impression rim at its top. While the tissue reached is generally yield- ing, it may still be harder in some places than at others; and it is on these different textures you want to equalize strain. That is, press against the soft parts, between the harder ones, so as to get an air-tight fit on the soft places, as well as on the harder ones. To do tliis, you simply, but slightly^, warm that part of the impression that is above the metal tray, and press gently, but firmly, hori- zontally against these soft parts, and cool it there while under strain. I emphasize: while under strain; otherwise the material might re- bound, when you 'd lose j^our pressure. Conforming is the name we give this right* angle'pressuj'e operation. While it is very sim- ple, it requires nicety of manipulation and care; nicety to do it and care not to afterward undo it. It requires more experience to properly con- form the rim of an impression to the tissues than to do any other one thing I '11 show you in this A\hole Course of eight to ten hours. But I hope you '11 not object to some nicety of operation and carefulness as long as less is asked of you than you require of the man who shaves you. Should you hesitate at simple trained touches like this, then never attempt the keener teclinics of tonsorial artistry. IN Dextal Prosthesis. 37 But let 's do it. AVatch me warm the rim of this upper impression (on the left side) by passing it back and forth over this hand^lamp. I'm slowly warming it through from the outer side inwardly; all of it from the metal tray upward. I '11 mildly warm it from the front*center clear around behind the tuberositj^ till it reaches about the softness of the palm of my hands. I test its yieldance with my finger — it 's ready! I slip it into the mouth and hold it up with the long finger of my right hand, and press gently to the left cheek outside, with my left thumb * and - hand, clear around to the front' center. See? My thumb^hand just fits the madam's face as if it 'd been made for the purpose. I push squarely against the cheek and on the front lip, and hold it so for about a minute. By that time the Kerr "Perfection" material will have "set" enough to prevent rebounding when I remove my thumb. "Hold still, JNIadam; don't move a muscle!" I reach over and dip my left-hand index fin- ger (clean-cloth=stall5covered) into my near'by cold'water cup and hasten to reach in under the lip and cheek (left side) and cool my now* conformed rim with a little pressure. If I have an assistant, I have lier do the cooling with a small syringe. But bear in mind, the cooling should be done while the pressure is on, for fear of rebound. (We have no long handles on our trays to be in the way. Ours are either about threes fourths of an inch long horizontally, or one* fourth turned down perpendicularly; or wholly removable, when no longer needed. 38 Greexe Brothers' Clinical Course Next, conform the opposite side in the same way. But here one special caution, doctors: after you have conformed one side of the im- pression, don't push it off from its gum when 3''ou conform the opposite side, and by so doing- make a side'slipping impression. This relates particularly to flat mouths. In a big mouth, with tliin lips, we can con- form both sides, and in front, too, all at the same time. Then there 's no danger of micon- forming one side ^vhile we conform the opj)osite side. I sometmies thus conform both sides and in front all at the same squeeze, by clampmg the whole face bet\\een my thumb and index finger of my right hand, while I hold the im- pression up to place with my left index finger; or vice versa. The amount of strain used in this conform- ing should be about the same as I make by suck- ing my cheeks in firmly. In fact, conforming by cheek suction would be the way if we could readily get our x^atients to do it. Say, doctors, when you have conformed the rim of an impression all around to the sides of the alveolar ridge properly, you have indeed accomplished a most valuable operation. Xow, we '11 go on and gently warm the heel= corners, return it to the mouth and hold it to place with our left-hand middle finger, while with our right index finger, cloth'covered, we reach up behind the tuberosities and conform there gently, too. We finger under and around by way of the palate usually, but sometimes via the more cramped cheek passage. It is all = important, especially in cases of roofless plates, that dentures fit up snugly, xicith- out undue pressure, around these prominences. It is essential to roofless plates. IX Dextal Prosthesis. 39 We sometimes have sueli=like conformation made by the i)atients tongue, cooling it well before removal, after held to place to set a minute or so. It is fine work to properly fit a plate aromid tuberosities ; but when done, it ^von't easily tip down behind when bitten-on in front. Xow clinch this heel=knob ])ointer in vom- minds : Xow, doctors, in practice we can frequently make all these steps, so far shown, by joining them. Xo language can ovev'praise the results of proper conformation of the rim of a plate to the yielding tissues! (Sixth Step.) CONFORM ("POST-DAM") BACK PALATE. Xow all parts of our correctable impression have been fitted to the parts, excepting the back palate. As this is really the most import- ant point for adjustment in the whole mouth, I have left it till the last. The im])ression material purposely reaches, as you understand, a little back beyond the metal tray; so the shortness of the metal gives room for a little cut-out of material under the end of the impression, leaving it thin=like there, similar to the rim. Xow, let us slightly warm this over'projec- tion, as we did that above the metal rim, so we can conform it to the yieldable tissues, onto which it reaches. I instruct my |)atient: "Xow, Madam, when I put this impression into your mouth, I want you to press it up gently, but rather firmly, at the back ])art, with your tongue, and liold it there a minute till I snap my finger. " When 40 Greene Brothers' Clinical Course "set" enough to not yield back, she drops hei tongue; and I finish with cold^finger pressure, same as I did the upper rim. The tongue being soft, it presses the soft material against the soft, j^ieldable tissue to exactness. If there are any granular or hard spots back there, as often there are, the ])ves- sure equalizes the strain against them and be- tween them. There is now a little general up^push all along the yielding line; a little valveslike press- ure that precludes air passage under it. Study well the rules and practice the meth- ods of fmding this exact right reach of your plate. (Index L.) Method A, by tongue pressure, is the way I 've shown you to conform a modeling'com- pound impression to the post'palate. It is mj^ preferable way, and my general way Lmder favorable conditions. But some- times we have deaf people and sometimes non- Enghsh^speaking people to deal with. (Some- one says: "Yes, and dam-phools !" ) Well, we must have a way to post'dam, in such cases, without the patient's help. Method B, by roof pressure. This we do by warming the rear of the impression, as in Method A, and then turning it up a little too high and pressing it up against the roof of the mouth, when the tissues will push it back, still leaving some valve^like pressure. Of course, we cool as before. While Method B isn't quite as accurate as Method A, it is far more so than any of the old scraping and grooving ways of getting rear j^ressure. Indeed, in many cases of granular palates, scraping and grooving for rear pressure IX Dextal Prosthesis. 41 won't do at all. Guess-work is rarely exactly cor- rect at the best. Method C is the third way of postsdamming; that is by finger pressure. We warm as before, but scarcely as soft as in A and B, and press it up and cool it with clear-cloth'Covered in- dex digit of right hand, at the same time holding impression to place with the long finger of the left hand. AVith experience and carefulness. Method C is easily accomplished and will succeed fairly well when there are no granules, or bumps, under the mucous membrane, to contend with.* But in no case does it compare in exactness with ^Method A, by tongue pressure. Bear in mind, that in any way the cooling must be done while the little j^ressure is on. THE ESSENTIAL ART IN HANDLING MODELING COMPOUND is to keep it cool after it has been adjusted; and to warm one part and adjust it without disturbing it elsewhere. But the work is no more difficult than many other things a dentist has to do. AN'^hile it requires far more skill to take a modeling-compound impression rightly than one in all-plaster, the results amply pay for it, and many times over. In the details of a single impression we do several different things, even though we do them all at once in combination. Now every one of these details can be done — ^^at least, wath tliis material (Kerr's "Perfec- tion)"; while not near all of them can be done with plaster. But the whole plastersunpression subject is to come up later on. 42 Greexe Brothers' Clinical Course UNITING DETAILS. Ipx actual practice we unite as many of these details as the case will warrant. Sometimes we can verv'edge the rim all around at once; in large mouths with thm lips, for instance. And then, again, as already shown, we can sometimes conform all around at once, even in- cluding tuberosities. And frequently we can both very-edge and conform all at the same step — perhaps not al- ways perfectly, but yet to stand the tests fairly well. Sometimes — in fact, often — we conform be- hind tuberosities and post'dam at the back pal- ate at the same time. It 's a quick and easy way. ^ Sometimes the center can be equalized with hotsstream (seldom necessary) and wave^press- ure at the same step when the very*edging is done. And it 's possible for an expert to do all these things thoroughly by two trijis into the mouth; and fau'ly well by a single trip. But trips into the mouth don't mean by the Greene methods what they do by the old ways, by any means. Our metal trays are not as deep nor as long as our finished plates are to be, as j^ou have seen. And our impressions, even from the first, contain so little bulk that patients are always agreeably suri^rised, after having heard so much about the horrors of impression^taking; and tliey almost invariably so express themselves — voluntarily, too. And for this one reason it pays to use the student's method of fitting a tray to an ap- proximate model and taking the correctable impression from this model. (Index L.) Bear in mind, we use no common, deep trays, even in taking an approximate impres- IX Dental Prosthesis. 43 sion; and seldom one-fifth as much material as hy the old methods. TEST THE COMPLETED IMPRESSION. Now, after post = dammmg (Index P), we make tlie final test. We slip the impression back into the moutli and have patient open and close, laugh, bite her finger, and swallow. If none of these movements throws the impres- sion down, they 11 not throw down a plate prop- erly made from it; for the latter will be a mold- ed duplicate from the former. Conversely, if any movement should loosen the imjiression, it would do the same to the plate. So you 'd know one or the other in advance. Really you '11 seldom find it necessary to make any correction after you 've made these six steps in detail. But, for convenience of il- lustration, we '11 suppose you make a blunder in your first attempt at a test impression. Af- ter you have post-dammed, you make your test. You 2^ush your impression up, and it drops down, even without any lip, or cheek, or swal- lowing motion at all. STOP, THINK AND REASON. After you got the length of the impression and then tested for roof^fit, you found it stuck up. After you muscle'tnmmed and conformed its rim, it stuck still tighter. But now, after you post^dammed its rear end, it drops. What 's the matter? The case is very plain. You over-strained the palate in post-damming. The over-strained parts rebound and push the impression off. What 's the remedy? Common sense — just ?ni*post-dam it, and do it over. li Greene Brothers' Clinical Course That is, warm it as in the first place, and post^'dam again; but ne.vt time with less strain. Keep on till you get a stick=up test. Don't object to doing this three^minute job over, for the alternative would be to make the j)late from it "over" — ^^maj^be several times. (Someone says: "We 're used to that.") Well, 3^ou 've re'j^ost'dammed and have a test ; but only a still test. It stays there all right when no muscles move. Now give it another test. Have your patient swallow vigorously. IF IT "SWALLOWS DOWN." ]My, how swallowing throvvs it down! What 's the matter notv? It either reaches too far back or else some small palatal muscle (one or more) reaches unusually forward. In rare cases such may reach quite a way forward. In this case, you will first re-test for length. Maybe you missed it a Httle in getting proper length in Step Two. If you find your impression isn't too long, then try for palatal muscular strain. That is, warm the top of the impression at the very back part, place it in the mouth, and hold to place, while patient bites on your finger and swallows vigorously. She can't well swallow without biting on something. The moving muscle will strain down the softened material; and thus a single ett'ort may cure the trouble. But make as many efforts as are necessary; then, of course, re^post^dam slightly and cool well before removal, as before. Take Xotice: After you find the slight indentation in your impression made by the swallowing test, you can use the mouth blow* pipe, as in special very*edging for muscle room on the rim, a while ago. IX Dental Prosthesis. 45 ABOUT NAUSEA. Xever cut oif a plate in front of the valve* i^ressure line to prevent nausea. Even if it cured the "gagging," it would make an easy- tipping plate. But shortening alone might not cure the gagging. Nausea is often caused by lack of pressure at the rear of the plate. Propersfitting (valve- pressure) plates can be worn farther back than poorly fitting shorter ones can be. But nausea is often from a mental delusion, and then must be cured by a process of "men- tal suggestion." If a patient falsely thought a bed-bug w^as imder her dental plate, she would "gag." And similarly, if she thought the plate Mas too long when it was not so. I have, as others have, cured scores of cases of nausea by appropriate means of suggestion. It has often been done by pretending to shorten the plate "just a leetle bit" without doing so. And all experienced dentists will tell you of cases where they cured nausea by treating the patient's will-power. Teach them how to ap- ply auto - suggestion. (Every dental college should be supplied with a "chair" filled with an expert instructor in Scientific Suggestion.) AVhen the cause of nausea is physical, or material, then combine physical and mental medicine. Benumb Mith cocaine and '"tan" \\'ith oak^bark tea, or any other astringent. But always mix in good Suggestion. MAKE MODEL ON TESTED IMPRESSION. Our impression now stands the actual test; we must "pour" oin- model before it changes. Unless we can fill it right away, we must keep it in cold water until we can use it. Bear in 46 Greene Brothers' Clinical Course Fig. k Fig. 5. Fig. 4 — Modeling comiiound impression as usually taken in common deep tray. Plate would have to be guess-trimmed to fit straining muscles — difficult if possible. Fig. 5. — In the same tray cut down and fitted to the mouth. Test impression just as taken liy the Green muscle-trimming method. No trimming of plate after made. Fig. 6. Modeling copound tested inijiression, jubt as taken; for plumping out tlie features. Common deep tray cut down for the purpose. IN Dental Prosthesis. 47 mind that even this "Perfection" material will warp some in a warm room. So impressions of modeling componnd must be kept cool mitil filled; rememher that. Better underscore this with red pencil. Before we pour our plaster, we '11 thin our rim down to the exact thickness we want our plate. We do it with our sharp x^ocket^knife. If, however, we want the patient^s face built out, we leave the rim thick, or even add to it (carefully) by tracing'On more from our blessed tracing=sticks. Then, also, before we "pour," we 11 polish the rim^edge by quickly passing it a very few times over our little spirit flame and blowing onto it quickly from our mouth. But be care- ful not to heat it, in the least, to any depth. Cool between each blowing and don't keep at it too long. The edge is now polished, and ten to twenty times quicker than tlie rim of the plate could have been j^olished after vulcanized. The com- ing plate's rim will now need the least touch of the polishing=wheel to com])lete it. Again, before \ve pour, we must see that our im])ression is dri/. If wet, the face or our model may come out soft, from lack of ])roper crystallization; that is, from too much water for the amount of plaster. We can soap*lather our impression thinly, or dust it with soa])' stone powder, but mc don't xcet it. It must have no visible water in it. I know this is contrary to high authority, but I insist on no water in my impression when I make a model. And I advise you to make some tests along this line; then report to your old instructors, who advised wet im])ression. 48 Greene Brothers' Clinical Course Within a stretch of four years, I asked two hundred and fifty some dentists what made their models sometimes come out of the impressions with soft, dusty surfaces; and just twelve an- swered me correctly — = under ' saturation and faulty crystallization. Of course, such a model would be unfit to vulcanize on. And yet how many plate^makers fail to comprehend this self-evident fact! HOW TO MAKE THE MODEL. Now, mix your plaster by the "fullssatura- tion" method. First put the needed amount of water in a clean, smooth, earthen bowl and then put the plaster in it. Don't "sift it in slowly," for some of it ^vould be wet much longer than the rest. But dump it in hurriedly; then hack it up-and-down with your spatula till it is wet through. Then mix quickly and "pour" before it begins to set at all. Always tap howl and pour of all the water you can. Then pepper*box a little on top to satisfy the watery surface, if needs be. If you stir it after it begins to set much, you '11 violate chemical action, break-up the forming crystals and make an imperfect body; which, though hard to cutj softens readily under heat and pressure. So, see that as far as pos- sible all crystallization ("setting") takes place after the piaster is in the impression; especially the first part of it. Extend the plaster just a little beyond the rim of the impression all around, and don't make the model needlessly thick over the arch. Reason for this later on. Now, after the plaster in the impression is well set, trim it (plaster) off all arovmd down even with the compound, using the impression IX Dental Prosthesis. 49 itself as the guide to your thin-ground, sharp knife. Hold your knife-blade at proper angle so as not to cut over into the bench, or shoulder of the model; which extension is to form the edgesrim of the plate. TO SEPARATE MODEL FROM IMPRESSION. First warm the metal tray and pull it off. Then set the impression into fairly Avarm ^vater, just deep enough to cover the impression ma- terial, and not to warm the model. Then turn the warmed compound down at one of the heel-corners to get hold, and peel the w hole impression off from the model. You now have a good, hard^surfaced model, with a smooth bench; which extension is to give the plate the exact same height and thick- ness of rim the impression had. Plaster should be "well stirred," but the least bit, if any at all, after it begins to set. As for myself, I like to polish the roof of my impression, same as the rim, so that part of my plate, too, will be smooth and easily kept clean in w'earing. 15ut should you do this, be sure and test for fit again before you pour your model. At first you '11 be sure to use too mucli heat in ])olishing your impression; for any heat is too much. And you '11 be apt to continue the gloss-warming and blowing too long. DON'T LET IMPRESSIONS CHANGE. Make your model at once, before the Impres- sion warjjs from the lie at of yonr room. Or else put it in cold water, and keep it in until you get time to use it. Doctors, this repetition needs no apology. You 've probably been let- ting impressions change before filling. [4] 50 Greene Brothers' Clinical Course The absolute unreliability of the average "brand" of modeling compound in holding its shape, and the ignorance concerning its man- ipulation, and the carelessness of dentists are the principal three reasons why compound is not in universal use for impression^taking ; es- pecially for full plates. METAL vs. PLASTER MODELS. Now as to the question of models. I 've given you what I conceive to be the best meth- od of making plaster models; that is, full sat- tiration, with no stirring after hardening begins; the same holding true of the various mixtures of plaster, sand, Portland cement, etc., etc. If you use good plaster and this carefulness in mixing, and don't spoil your models, nor pack so as to strain them any after they be- gin to soften (by natural disintegration, that takes place under heat and moisture at about 300 degrees F.), you may get through your case without much change in your model. But under the greatest skill in mixing and pouring and flasking you will always have sonie change; possibly, however, in a direction to do more good than harm, as to that. Under conditions, plaster will expand and contract; and its compressibility is sometimes astonishing. To prove this yourself, make you two plas- ter models from the same impression. Then vulcanize on one of them and try yoiu- plate on the other one. There will always be some lack of fit, which shows just what change took place in the model you vulcanized on under moisture, heat, and pressure, including the force of ^ailcanite shrinkage by hurried cooling. IN Dental Prosthesis. 51 So the less pressure j'ou apj^ly in packing (especially after your model begins to soften) and the more slowl}^ j^ou cool a flask, the safer you are from serious change. And now, to fully imx^ress j^ou with the com- pressibility of plaster, you can easily make a convincing test for yourselves. Prepare a flask, both halves filled with the best plaster; place a silver dollar between the two halves and boil, and squeeze, and vulcanize as usual. Then open it; you '11 find your silver dollar entirely hidden in the plaster. Then use tivo dollars, one on the other, and record your impromptu ejaculations. (I made this exposure of the faultiness of plaster at the National meeting at Birmingham in 1909.) GREENE'S NON^CHANGEABLE MODEL SYSTEM. But I 'm glad to report to the dental pro- fession that, after years of puzzling over the A'^xatious question, I liave at last solved the problem. The problem of avoiding tliis inev- itable change in j^laster models, both before and during the flashing and \Tilcanizmg j)rocess and in hurried cooling. I do it by disposing of 95 per cent of the amount of plaster in a model, to begin with; and then holding the 5 per cent into place so the infinitesimal change in it can't do any perceptible harm. I make an approximate model of aluminum with its surface prepared to retain a thin film of plaster. Tliis aluminum model is of a size and shape to slip down into and approximately fit, but still very loosely fit, the impression. In fitting this non-changeable metal model to the impres- sion, I first besmear its face^surface with a little 52 Greene Brothers' Clinical Course plaster; then dip^jjour some into the impres- sion and plunge the face=covered metal model into it; then hurry up and complete, the same as if the model were all plaster. I then trim the model A\hile yet in the im- pression; and also remove the impression ma- terial from it — both just the same as with the all-plaster one before mentioned. Xow we have a metal model, thinly ve- neered with plaster; which facing is necessary to fit it to the impression, and also to enable the removal of the metal model from the vul- canized plate. But the amount of plaster used is too small for any proportionate change in it to be noticeable. I may here add that in some cases of under* cuts in the mouth the case must be left in the flask till the softening takes place in the plas- ter coating on the metal model. Leave the case in flask, if convenient, over night; in fact^ that 's the right thing to do in vulcanite work anyhow. But, instead of making an approximate mod- el for each case, I have a set of them already made, from which I select the one needed. It consists of one hundred models and is expected to accommodate almost any case, full or partial. The set is so systematized in size, shape^ number, and letters that one or two minutes is sufficient time for making the selection. For swaging (by the new^process methods only), we veneer our metal mold with a half- and-half mixture of Portland cement and plas- ter, well pulverized together in a mortar before wetting. This swage - model must thoroughly harden l)efore use. (Here the class is shown how to fit Greene's nonschangeable, approximate metal models to IX Dental Prosthesis. 53 an impression. See especial instruction in Ap- pendix hereto; under heading: The Greene Ready ^Xade Xox^CHxiXGEABLE Approximate Models. modeling=compound impressions in difficult CASES. Our instructions so far apply to ordinary cases. But occasionally we find mouths where other different means must be used. For in- stance, here we have a case with protruding ridge in front and an "underscut" above it. To take this impression and preserve the under-cut, we first take it fully up to the be- ginning of the turn that makes the imder^cut. Then we trim this edge of the impression down so as to dispose of all of the under-cut. Now cut two or three little notches in the trimmed^off edge. Then varnish tliis edge and brush a thickness of tm^foil onto it. The var- nish is to hold the tin^foil onto the trinmied edge of the impression. Now we use the "Perfection" tracing-sticks and trace-on enough material to bring the rim up to its proper height. Then warm the traced* on addition over the spirit4amp and quickly slij) the impression into the mouth, and very- edge and conform this addition down onto the main part just as if the two were all one piece. Tliej^ cool well and remove. In taking it out of the mouth, the addition will pull loose from tlie main body of the rim, and the impression come out in two pieces. Then, when out of the mouth, we place the addition back onto the impression where it be- longs, guided by the notches, and we have our full impression, under-cut and all. 54 Greene Brothers' Clinical Course Should j'ou wisli to take an impression some- what over a bulging tuberosity, you can use plaster for the addition, if not too thinly mixed. Of course you understand the tin^foil is used merely as a sej^arator between the impression and the added edge over it. If you take more of the underwent than you can use, of course 3'ou '11 have to tip the plate accordingly to enter it over the bulge. Prac- tically, it 's no use to take more of an under- cut than can be comfortably used. SOFT, FLABBY, ALVEOLAR RIDGE WITH HARD ROOF. Such is about the worst case you "11 c\'er have to deal with. The ridge hangs down loose- ly and flips to and fro as j^oui' lip does when you talk. The right thing to do is to absorb this flabby tissue ojfj and reach a harder density. This can be done, if patient can be controlled^ ^^'ith perseverance and patience. I have had usually good results from quarter strength iodine, with, say, two per cent of it carbohc acid. It is applied on bibulous paper worn on a temporary plate. One of shellac base^plate will generally do. In connection with the medicine, liberal fric- tion should be applied several times a day, preferably with dry woolen cloth. The iodine, the friction, and the pressure together should complete absorption in two or three months. But I '11 give you two recipes that are prob- ably better; or, at least, quicker. They were given me personally by my esteemed friend, the world^known orthodontist, Dr. E. A. Bogue, of New York city— 63 W. 48th Street. IX Dextal Prosthesis. 55 "RECIPE NO. 1, ''Vienna Paste for Reducing Soft Gums. [Translated.] "Caustic Potash, 50 granmies. "Quicklime, 60 grammes. "Pulverize the two substances in a heated mortar; mix them rapidly and thoroughly, and put them into a wide^mouthed bottle with ground glass'stopper. "We make a soft paste, dissolve with a lit- tle alcohol and apply in the same way as caustic potash. "Leave the caustic twenty minutes or more in place, if a small quantity of the paste has been used to make a deep opening. Wash the eschar wWh acidulated water to neutralize the remnants of the caustic. "To lessen the pain caused by Vienna Paste, Dr. Piedagnel added a quarter of a granmie of hydrochlorate of morphine. "To make sure of the action of Vienna Paste, 'Dr. Dannecy dissolved the potash and lime in an iron spoon. "Vienna Paste melted in a sjjoon, or poured into a leaden cylinder, is a caustic which destroys quickly and deeply." "RECIPE NO. 2. "Dr. Sass's Formula for Reducing Soft Gums. ^^lODIDE OF ZINC. "Zinc Sulphate, as much as will dissolve in cold water. "Dissolve one ounce Iodide Potasli in two ounces water, and add as much Iodine in crys- tals at it will take up. 56 Greene Brothers' Clinical Course "Then take equal parts of above solution and put them together.'" Iv'e laiown dentists heroieally to use a pair of curved scissors. But here in this lesson we '11 go on and do the best we can without removal of tissues. We '11 compress it to a degree of equalization of stress between it and the hard roof. We'll just take the impression as here- tofore shown in a plain, easy case. Of course, the flabby tissue turns outward, as our lip does when we push it with our tongue ; but we '11 push it back again. The metal tray, in such cases, must be quite loic, so as not to interfere with such back^pushing. Now, while the impression is still soft, we finger'push onto the outer rim until the soft gum tissue behind it is back to about its normal hanging; then chill well and remove it. Next we hot*stream the impression from our spout*cup till its bottom surface (not to rim* top) is quite soft; and re ' take with wave= pressure. This time the cooled outer rim of imj^res- sion, being hard, prevents the flabby flesh from turning outward as it did before. Our upward wave^motion strains the mushy flesh and causes it to compress and consolidate onto itself; that is, becomes more dense. We repeat this several times if necessary, until ^^e get tlie flabliy tissue almost to a strain- ing or rebomiding density; that is, till the im- pression fits the soft ridge and harder roof with approximate equality of stress — ^not what we 'd ti:ish^ yet approximately so. Next w^e warm the impression's rim^edge, hold it up close and very*edge, as instructed before, in musclestrimming. (Index V.) IX Dental Prosthesis. 57 Then we re* warm rim (outer side) from metal tray to top, return to the mouth, and conform^ according to instructions for conforming here* before given. (Index C.) And lastly, we 11 determine the length rear- ward, and post*dam according to density of back j)alate, as you 've been carefully shown. And now for test for "sticktion." We ought to have an impression that will not readily be thrown down. It may rock, if pressed on in front or on sides, but, while it gives upw^ard on one side, it gi\es downward oppositely. Our valvespressure*fit all around saves it from tip- ping entirely loose. While such a fit isn't fully satisfactory, a plate from it can be ^^•orn with considerable comfort and practical utility. This depends much on the persistency of the wearer. I 've known several plates to rock an eighth of an inch and yet worn with satisfaction. I mean in these cases of flabby ridges. The "play" of the valve^pressure kept them from leaking and tipping loose. FLABBY IN FRONT AND HARD ON THE SIDES. Another case of flabby gum is, say, Avhere the tissue in front is soft, while the side ridges are hard. In this case, we take our correctable impression as if it were flabby all around. This turns the soft gum outward. Then, while the compound is still soft, ])ush it back (in front) until the soft ridge is to its normal perpendicular position; and cool before removal. Then take it (impression) out and use the hot*stream once or twice all over the inner sur- face, each time re*fitting it to the mouth. Sometimes in equalizing, in these local spon- gy cases, it will be necessary to soften only the 58 Greexe Brothers' Clinical Course impression over the hard tissues, ui order that these rigid parts may cut down into the soft- ened material, while the soft tissues are being pressed up by that part of the compound that is not soft. To heat one part of the impression and not the other part is very simple: Just pack cot- ton over the part not to be heated, before pour- ing the hot^stream; then immediately remove it before re-taking for equalization. Thus the bony ridge cuts into the softened impression and causes the hard part of it (im- pression) to correspondingh" push up and dis- place the soft flesh, to equalization of pressure. To recapitulate: the process is the same as we had a while ago with the case of soft, flabby ridge all around. The idea is to hold the loose tissues in their normal position; then compress and coiisoUdate them, so as not to yield much when bitten on, and to rebound and keep their room filled air=tight when not under strain. Study such cases, and study your patient, and decide whether you want to remove the flabby lissues or equalize them, and then act accordingly. A VALUABLE REVIEW. (Here the whole matter of equalizing the soft tissue with firm ones was repeated in clinic till the class could explain themselves. Also a review was made and the class re^impressed with the importance of conforming and post* damming, to the purpose that plates may not tip down behind while bitten on in front, or tip down on one side while biting on the op- posite side.) IX Dextal Prosthesis. 59 ROOFLESS PLATES. By a roofless plate we mean one whose roof* center is lacking. It is a fact that fully one* half of all ujiper cases might be made roofless. Indeed, many more could be if we had not mal= educated the pubHc to the idea that dentures should stick tightly in the mouth. I say "mal=educated," because from long observation and personal experience I 'm con- vinced of the fallacy. It 's not the tight'SticMng plate we need, but the one that can be worn more loosely and more comfortably tvithout be- ing th'oicn down, or up, by straining tissues. It is a truth (surprising to some non'think- ing dentists) that cases are numerous w^here a roof covering the entire palate is detrimental to retention of the plate, as well as to the comfort of the ^^earer. A toothless upper jaw with a very hard cen- ter is frequently one of them. Especially is this so if, as is generally the case, the rear of the plate doesn't reach back beyond the hard part, and doesn't fit up on the soft so as to make valve-like pressure, I mean, to plainty put it: if a plate is cut off too short on a hard=roofed mouth, it 'd bet- ter be cut clear out, up to the ruga or even beyond. In that case, the plate would settle as tlie ridge absorbed and the fit would still be maintained. It is sometimes funny to see dentists bug out their eyes at the mention of a roofless full denture when they are already making roofless partials, more difficult than the others. But, to make a roofless full plate practica- ble, its rim must reach the proper height all around, including tuberosities, and have a good, close valve-fit on the inner edge thereof. 60 Greene Brothers' Clinical Course This is done by muscle'trimming for height and conforming for pressure, as you 've been shown in other cases — a cheek fit^ so to call it. Then it must also have the same sort of a fit on the lingual inner edge. Hence the plate mustn't be trimmed off quite to the hard bor- der of the ridge, for there we can't make the necessary valvespressure to prevent its tipping. It should extend down to where the mouth is a little soft. And then, instead of post^dam- ming, we sidc'press the edges with firm tongue pressure; in some cases, with finger pressure. Don't attempt to get the "extra pressure" by scraping the model, for there may be vari- ous densities of the half-soft tissues. Scraping is guess=work at best; and you can't test it. When sidespressed with tongue, or even finger, we can test for satisfaction of fit. And again here I repeat without ax)ology: All conforming must he done by cooling the material while it still presses the yielding tissues. While an impression for a roofless plate is taken, in a general w ay, the same as for a roof plate, especial care should be made in every step and detail. The rim and heel trimming (very-edging) must dispose of all muscle strain, and yet in a way to leave no leak. ''Relief without leak." Take notice: When I say you can't cut a plate off where it edges on a hard part, I mean from the middle of the mouth rearward. It may rest on such j^laces forward of the center without harm; for the more pressure there, the tighter it fits. But I repeat: When you have a very hard place, better cover model there with tin-foil, when packing, to provide for the inevitable set- tling of the soft parts in adjustment, by wear- IX Dextai. Prosthesis. 61 ing. The softer the soft parts, the thicker the tin-foil should be. INSTRUCTIONS TO PATIENTS. When you make a roofless plate, be sure to instruct your patient to practice chewing- chipped ham or dried beef on both sides at once, between meals, for a week or two, to evenly adjust plate, all around alike. This can be done also by a habit of biting the teeth together without feed, if the occlusion is good. Instruct her to do both. Well, in fact, this should be the instruction in all cases of artificial teeth on plates. It is best, generalty, for patients not to try eating at table imtil they have practiced on simple food, on both sides at once, and feel the need of their teeth at mealstime. When they can do a little better latli tlie teeth than tcithout them, all is safe — "the Ru- bicon crossed." But don't over^do the sug- gestion of "perfect satisfaction" unduly soon. JNIuch experience induces me to insist on this advice to dentists — learning at first on both sides at once. And they '11 always gratefully remember me for it, too. EXTRA SUPPORT TO ROOFLESS PLATES. When you make a roofless rubber or cellu- loid plate, strengthen it across the front pal- atal surface with perforated gold or other metal plating. To do this, you first fit your metal su])]Jort to the model approximately: then, in packing, first lay down a thin sheet of vulcanite: then the perforated plate onto this rubber: and, lastly, another vulcanite slieet on the metal. 62 Greene Brothers' Clinical Course But this instruction belongs to our last les- son of this Course. RETENTION OF ROOFLESS PLATES. Roofless full plates will not generally stick up as tightly in the mouth as others, provided the full roof ones fit just right, and that right fit continues. But they stay quite well enough if fitted properly and persistently worn to easy adjustment. In furnishing roofless plates, use careful judg- ment as to "indications" of the mouth and as to the good sense of your patient. Good ridges with prominent heels indicate roofless plates; and real desire for them indicates the wearer. Few people having worn roofless plates would be content with any other. A roof does inter- fere with taste to some extent; and, if in no other way, by obtundin^ the sensitive nerves of the tongue by frictional contact, the same as work with a hoe handle will "harden" the fingers and hands, so a blind person can't well read raised letters. Though I formerly argued, in the fashion, otherwise, I now "know for myself, and not for another," better. Don't hobby'ride roofless plates, but make them unhesitatingly when a roof would be det- rimental or unpleasant. Then get a fair price for 'em. This you can easily do with a reputa- tion for making them. Here the lecturer sur])rises the class by show- ing a roofless denture in his own mouth and chew- ing tough beef steak and ham, to their complete satisfaction. PARTIAL UPPER IMPRESSION. Now we come to the easiest of all impres- sions — partial upper cases. IN Dental Prosthesis. 63 Cut your tray low, so the material won't run up much onto the natural teeth. If it rims high, you may not know whether the over-lap holds the impression tight or whether it 's the suction to the roof that does it, in your test. Trim your tray also a bit shorter behind than you want your finished plate, so you can later on post*dam impression with tongue press- ure or otherwise. (Index L.) Now be dead sure your tray and material can't part company. Better have some small holes through the tray, in addition to the melted* on, stick = tight lining heretofore shown. (In- dex S.) Pile your water- warmed compound high up in the center and \\ell forward, and lastly warm well over spirit flame; then take as show^n for full mouth. Cool tJiorougJdij with sponge held on under side, as shown before, and remove with caution. Then get length (Index L) and post^dam (Index P) as in full case. In partials you con- form only when visual adjacent teeth are miss- ing. Mind, now, we 're talkino^ about jmrtials. But, mark you, we 've had only a simple, easy case, where there were no leaning teeth nor bellsshaped crowns to interfere with removal of impression. "There are others." (Class re- sponds: "Yes, there are others!") LEANING TEETH AND BELL=SHAPED CROWNS. In cases of leaning teeth and bell-shaped crowns, you '11 first use some of the "Perfec- tion" material to build around and core them out coiie=like*shaped at all ])oints. Then var- nish the ;es of plates: so this couldnt he even a complete temporary refit, though good as far as it goes. Compete lefits must include the edges of plates as well as the ])alate and ridges. PERMANENT REFITS WITH VULCANITE. To refit a vulcanite plate completely and permanently — rim. heels, and tuberosity, in- cluding position of teeth and occlusion, — you first see that the teeth stand as desired. If not, oil them and heat them with a mouth l)low=i)i[)e, and ])ush and i)ull them to the positions desired, and hold them in ])lace till cool. This relates mostly to the front six, hut may include any others. 80 Greene Brothers' Clinical Course If there are any cracks in the plate from changing position of the teeth, pack softened vulcanite into them, as you 'd pack soft foil into a carious cavity. Next see that the teeth occlude with their opponents as you want them to, whether the latter he natural or artificial. Not necessary that the plate itself should even touch the mouth in this re=occlusion; just so that the teeth come together properly. If any tooth is too long, either grind it off or take it out, make more numi aho^'e it and then set it back up deeper into the plate. If one is too short, loosen it and pull it down to proper touch against its opponent. Your teeth now both set and occlude as you wish them to. Xext file the rim of the old plate down below where there is any under=cut, including around the tuberosities, and trace=on enough modeling compound for a new rim; and cover the whole jDalate and ridge surfaces with a facing of thin compound, as in a temporary fit with compound. With your material thus in ])lace, dip the plate into hot water and have ])atient take her own impression (in the old denture) by biting down lightly. Do this twice or three times if necessary. When it will stick u]) in the mouth, that 's proof that it fits. When the roof and ridge stand the test, then go on and very^edge the rim all around. Be sure each muscle has valve'tight room to move in; that is, I'elief without leak. Then, next, you 1\ conform all around, in- cluding behind tuberosities, as in an original im- pression. Till now we 've left the most im])ortant step IX Dextal Prosthesis. 81 yet to be done: the valve^fittiiig of the posterior edge of our plate's palate. If the old plate reaehes l)ack to where it should — that is, onto the yielding soft, and not onto the moving, straining soft, — it has been already post^danmied, in the taking of the im- pression, by biting. That is, the hard plate has foreed the eompound up against the soft tissues and made the needed valve*pressure strain thei'e. If it doesn't go back far enough, you '11 file it off square and trace=on enough modeling- compound to make it reach into the stationary soft tissues. File it s(]uare to vulcanize more length onto it. ^Vhen you get it long enough, with a little to s])are, you then apply the rules for getting exact length, and post=dam pro2)erly, preferably by ]Method A — ^^tongue pressure. You now have the set of teeth, the "denture," as you want it. It stands the test of mouth move- ments. Ciet your flask ready. See that its edges fit together in a way not to allow any tilting, for that iiiiglit harm the occlusion. Fill tlie lingual side of ])late carefully with ])laster, avoiding all air=])ub})les, and at same time fill the first half of the fiask with ])laster, and push plate into it with teeth ])()inting down- ward — after having adjusted and plastered on your Greene Occlusion Retainer. Then scra])e off excess side plaster and varnish with Kerr sejjarating fluid as usual in fiasking. Now fit on the ring of your fiask and "dou- ble^fiask." First carefully fill your impression, same as if you were making a model; for, indeed, that 's what you are doing — the very one you are going to vulcanize onto. I^et your plaster harden well, the remainder in vour ])()\vl beino- vour "uide. When hard. 161 82 Grkexe Brothers' Clixical Course jjlace the flask over a spirit name or on a warm stove and, wlien you can feel it is slightly warm through, open from tlie heel first. Your flask is opened, and your model is in the last half of it. Cover it with thin tinsfoil and cut some small vents, and it '.s readv for use. Now turn to the set of teeth in the first half of tlie flask, remove the compound and scrape the old plate to get a new surface ; then jjack and vulcanize as usual. But leave all vulcanized cases in flask for several hours before opening, if possible. It takes time as well as cool temperature for vulcanized rubber to crystallize to its best — to "season." Leave case in flask over night when you can. Quick vulcanizing, quick cooling and quick removal all help to make brittle and warj)- ing plates; don't doubt that. If you 've followed instructions, yoin" ])late will come out clean and nearly flnished — no filing, no scraping, no grinding of teeth, and little polishing. Remove the tinsfoil with a thin amalgam of mercury and tin*foil, or tea*lead. made in your hand and rubbed on with your finger or a Avad of cotton. Xow you liave a fin- islied refitted lialf=soled" denture. TO REFIT WITH PLASTER IMPRESSION — "PASS=WORD METHOD." If you wish to take the impression in plaster, you simply first file off the old rim and heels and add compound, and very^edge and conform and post^dam, so as to confine the plaster; and then take it according to the "pass^word." (Index P.) Of course the patient will bite down to get the impression, instead of you pushing it up in her mouth. (Index P.) IX Dental Prosthesis. 83 COMMON, OLD=FASHIONED REFIT OF RUBBER PLATES. But if you want to make merely a common, old=way refit, you can do so by merely taking the impression in plaster or compound alone, Avitliout our improvement in muscle relief=with- out^leak and witliout our rim and heel valvc' pressure fitting. And you can do it in a sort of approximate, halfsshod ^vay by using semi-licpiid vidcanite paste for taking the impression. But these preparations will not j^roperly equalize pressure even on difficult plain surfaces, to say nothing of their utter lack in muscle'trimming and valve* edge^pressure (jualities. so essential in good plate* work. They are poor substitutes for good com- pound or fine plaster. (Coarse compound and coarse, stiff plaster won't do at all.) Until you "get your hands in" by a little experience, you may get the best results in re- fitting by using impression plaster according to tile five points of the ''|)'i^^'^^'^^"^^- (Index P.) TO REPRODUCE PLATES FROM OLD ONES. Yon can generally — in fact, nearly always — get a few more dollars, and do your patient more justice, by substituting a new plate in place of the old one, instead of refitting the latter. And it '11 take you but a few minutes longer and cost you but a few cents more. First get your contract to refit, and go on and take your impression for that purpose. Then inform j^atient that while you can and will be responsible for the jit, you can't be for the breaking of the ])late: since every time an old plate is vulcanized it becomes more brittle and more liable to break again. But you 11 put in all new material and then warrant the new 84 Greexe Brothers' Clinical Course plate not to break. (First-class rubber properly vulcanized at lowest temperature, long time, against tin=foil or gold=foil, will not break.) A ])atient, after you have begun her work, will very seldom refuse to give you big pay for your cjctra few minutes in making her a new plate instead of refitting her old one. To do this, you do just what I have de- scribed and shown you in refitting, from the first to last, up to the time you are to remove the material that constituted the impression, ready for packing. But, instead of removing the impression material and scraping a new surface on the old plate, you just remove the whole thing, plate, material and all, and pack for an entire new plate, instead of for a lining. This is done by placing the half^flask. con- taining the set teeth, over a hot flame and heating it hot, and lifting out the plate from its imbedment; usually teeth and all. As you lift it out, some of the plaster around the teeth may break loose: })ut just cement the pieces back to their places and go on. Heat your teeth on the ])late (after oiling them to prevent cracking) by pressing them back and forth over a small spirit flame, and pull 'em ofl" in the usual way. Then stick each one back into its place in the investment, pay- ing no attention to the little rubber that may remain fast to the pins — it '11 do no harm. Pack and vulcanize just as for a new set of teeth. Then you have made a new j)late, out= and*out, with no more work and but a few cents more cost to you than to have refitted the old rotten one. But, now, bear in mind, if you know in ad- vance that you 're going to renew instead of refit the case, you can and should use wax in IX Dextal Prosthesis. 85 changing the position of the teeth of the old plate (before taking the impression therein), in- stead of packing the cracks with vulcanite, as in refitting. In this renewal, if the old plate didn't fit nor the teeth set right, all will be corrected together in the new plate. In renewing it is an excellent way (in occlu- sion correction), to take the teeth all off of the old plate and set them back into their several j^laces, using sticky wax in their re=adjustment. In this way on separating the flask the teeth will remain in tlieir embedment; avoiding the scaling loose of plaster. Of course, you will adjust over the ends of the teeth the new invention, Greene's Oeelii- sion Retainer, before the first investment; this to prevent displacement of teeth by pressure in packing and vulcanizing and to avoid after grind- ing. ^ You can refit or renew ])r()ken plates in this way: Fasten the two or more pieces together with common filling cement or elsewise, trim down the old rim and take the impression as I have shown you, either in "Perfection" ma- terial, or in plaster by the "pass-word" way. Then go on as you have l)een sliown. If you use cement to fasten the pieces together, better strengthen witli ])ian() wire additionally. And bear in mind, in all these repairs, re- fittings and renewals you can test in advance for final results, the same as in testing full impressions. 86 Greexe Brothers' Clinical Course THE GREENE READY=MADE, NONCHANGEABLE MODELS. To make sure of no clmiige from your test impression by faulty plaster models, or mal'Use of even o-ood ones, you can use the (treene ready-made non=changeables in refitting and re- newing plates, the same as in original A^'ork. And you should especially use them if you tm-n your work over to ignorant or careless assist- ants or other irresponsible helpers. PRECAUTION IN REFITTING AND RENEWING PLATES. X. B. — ^^If your plate is thick, scrape it down on the lingual side and polish it before having patient take her impression; else you may get your new plate too thick. Also have your impres- sion material soft enough that the old plate may show through it at places for the same reason just given. Also see that you don't get too much rubber in your ])acking and that you have ample vents for surplus, to prevent over-strain in squeezing. To prevent getting a plate thicker than your baseplate use the Greene Roof Re-enfoveer shown in connection with the Greene Occlusion Retainer, Better always use the cloth plan in packing. Also iliiuh; if you fail to get the metal edges of flasks together, your plate will ])e corres]3ond- ingly too thick and the teeth that much too long somewhere. ^Nlost of the ])oints of this lectiu'C, now closed, will be further illustrated, in our next two lectures, in their application to other work. IX Dextal Prosthesis. LECTURE NUMBER TWO. LOWER DENTURES. FIRST: A MODELING=COMPOUND IMPRESSION IN DETAIL. AVell, doctors, we now come to what gives more trouble to dentists generally than any other part of i)late=work. In fact, to most of them it 's the most difficult of all dental work. That is the making of lower full, or partial, sets of teeth satisfactorily. In this clinic*lecture we '11 simpty apply the princi])les laid down and ex])lained in Section No. 1, so far as tliey are applicable. With these principles, in connection with others especial to lower cases, I ho]:)e to show you that it is as simple and easy to reach satisfaction in difficult lower cases as in difficult upper ones. As we did in the u})per, so we '11 commence M'ith a modeling^compound impression and a full ("double") case. In lower cases the common deep and long old travs, used in the usual old ways, are even, if possible, more absurd than in upper ones. Such trays being longer and broader and deeper than our ex])ectant denture is to be, you not only take in more area of the mouth than is needed, but generally distort the ])arts tlie plate is to cover. Take an impression of a distorted mouth and, of course, the ])late won't fit it when it resumes its normal slia])e. 88 Greene Brothers' Clinical Course With a too extensive tray, you not only press the soft and loose tissues out of* place, hut you strain the moving muscles. You take the impression of the moving muscles when strained down. Then, when you insert the re- sultant plate on them icifhoiit strain, of course tliey rebound and lift it up. But should you carefully not strain some muscles down by pressure, but mildlv get them at normal rest, they will still lift up above the nor- mal when strained in biting and chewing". (This is a new thought but a true and most important one, as will soon be demonstrated.) Then you diagnose the case as one of the "Johnny-.Tump-ups." Then you file the plate off by guess to re- lieve the muscular strain, when it turns out, in most cases, that you 've cut off too much and have a Icak^ as well as a relief. What is needed is, again, ?'elief without leak. The old college professor's rule, "Trim your lower plate till you think you have spoiled it, and then trim it more till you are sure you have spoiled it," is a grave error, to put it mildly. Scores of them seem to think they individually originated the "gag." Lower plates should cover all the territory compatibly possible, to have corresponding areal contact and consequential atmospheric pressure, or "suction." The less areal contact, of course, the less chance for atmospheric push=down. The fact is, the very contrary of the "keep* on=trimming" advice is true. The more of the ever-present saliva bed that is covered by a lower denture, the better suction it will have; provided the tissues are not strained, of course. This is simply self-evident to any one who can reason at all. IX Dextal Prosthesis. 89 But this matter of extension and limit is one to be dealt with an hour later on. For the pres- ent, we want to take a lower impression of the parts in their normal position, and without undue strain on the moving muscles. In some — in fact, many — cases, we must un- avoidably cover these straining tissues; otherwise our plate would be so "trimmed" as to have little or nothing left. I find many such ones. But if we have a system it must cover "ticklish cases" and all. Now, to take an impression of a flexible tis- sue with room for reflex action is the problem. We '11 illustrate by taking it first in a way almost sure to fail; which means the old way in common use. But, first of all, we '11 find and inspect the muscles most concerned. Xow, each one of you place your right in- dex finger in your mouth, left side, for instance, as far back as you can get it, on the outside of your lower teeth. And, as you press down, open and ch)se your mouth, and especially bite down on your finger — several times, please. I see you look surprised, for you know what it means, ^'ou cpiickly anticipate my talk. You have learned, before I tell you, just wliat ha])- pens when you use a long, broad-ended metal tray in taking an impression of a masseter mus- cle and its coverings. You take it in a relaxed, at^rest, or even a strained'down condition. When you open and close your mouth, and especially when you ])ite doicn on your finger, you feel what irresistibly lifts it. It lifts u]) even though you bear down with several pounds' pressure. Speaking ])ractically from a resistance stand- point, you can and do take a lower impression 90 Greene Brothers' Clixical Course in this way (with your thiimhs) at many pounds' strain=pressure. AVhile you dont exactly push down on your extended metal tray at a twenty or forty pounds' strain, you do take that part of the impression in a way to give the masseter muscle and its surroundings so much capacity to lift the plate; and they use as much of the capacity as is necessary to lift it. These figures are correctly illustrative, if not exact. AVhy. doctors, I see some of you are so hyp- notized with concentrated surprise that you are still holding down: down on the main muscle that causes so many of your lower plates to have the ' 'Johnnys j ump^ups. ' ' Xow, how are you going to take an impres- sion over and of these muscles and avoid the jumps=ups in your plate? Some one suggests the common old method of "relief" hy cutting away the denture plate to give the straining tissues room to move in with freedom. Yes. if you tile it away enough, that will relieve it. But in cutting off your plate short at rear ( or even at side=rear ) , you lose the most useful and most effective part that operates to hold it down; that is, the most effective part when it is properly fitted and left there. By filing it off, you lose not only just so much area of contact for atmospheric pressure, but lose it at the longest and most powerful end of the lever. The farther hack a plate reaches, the longer your lever is: and the more surface it covers, the greater the power at the long end of the lever. This is sim})ly mechanical philosophy that no one wi]l gainsav: assuming tlie fact that IN Dental Prosthesis. 91 the front teeth constitute the fulcrum in tiie calculation. Assuming there is no under-push upward, like a straining tissue, it would be a matter of only a little atmospheric, or other weight, to i)re- vent rear tipping. If the plate is left h)ng, or broad, saliva gets under it and operates like water between two ])ieces of glass, wlien they "stick" together — according to area (jf contact. Hence the mechanical value in the length of a lower ])late. But tlie condition is. there must be no uplifthig understrain to offset the atmo- spheric downspush, of course. TO AVOID STRAINING THE MUSCLES. Then let 's take the im])ression in tlie first place, so as not to strain the masseters, or other muscles. The first requisite in this is to jit the tray to the mouth. We '11 take, if need be, an old, soft=metal tray and with curved platesshears cut it off be- hind ; and trim it down in front; and narrow the sides; until it is even shorter at rear, and shallower everywhere, than our coming finished plate is to be; cspccialli/ shorter at rear. For we don 't want it to run back onto the condyles, nor onto the troublesome masseters at their outer sides. If we sti-ain things about the con- dyle vicinity with ()nly oui- material, we can cor- rect that. And it is only a correctable impres- sion that we are i)rei)aring to take. Besides reducing the old tray in length and depth, we Ml also cut its handle off to a])out three=quarters of an inch; then thin thai down, so as to reduce overlapping weight and avoid 92 Greene Brothers' Clinical Course ti2)ping. Better use the GreenesKerr trays that need Uttle cutting down and no cutting off. A long, heavy handle to a lower impression tray is about as useful (and about as much in the way) as a rhinoceros's horn=snout would be on a pet pug's face. How nicely the com- parative rhinoceros=horn would teeter the pup- py! And how vigorously a long, heavy handle would teeter a lower impression when you let go for a staysdown test! And yet our "best men" never kick to go into a supply house and find none but horn* snout=laden lower impression trays in the well* filled show-cases. The metal tray should fit the alveolar ridge (or over where it used to be) approximately well, so we can use a small amount of impres- sion material. Such a tray, with minimum contents, is a great convenience to the dentist and satisfac- tion to the patient. All told, our bulk shouldn't be twenty per cent of the average in conmion practice, by old methods. As in the upper case, there are trco tca?/s of fitting a tray to a loM^er mouth. TJie first is the student's way — a good way, too, for anybody. In this way, with a m e d i u m tray ("de- horned" over masseter region), we first take a hurried, approximate impression in modeling compound, and cool it somewhat in the mouth with cold water, thrown in with a piston syringe. Tlien, with quickening salt, or better, sulphate of potash, make a hiu'ried, approximate plaster model. Then with the thumb and fingers, or pliers, bend the tray to fit it approximately, turning the heels of the tray up a very little, to prevent metallic rear*gouging. IX Dental Prosthesis. 93 LOWER TRAYS. Fig. 10. — Absurdity. Too large for any nioutli. For large ridge. Fia'. n. — Co.-\iPROMisK. Fig. 12." — Reason.vhi.k. For niediuin size. [These cuts represent three- f on rllis of full size of lower trays.] 94 Greexe Brothers" Clinical Course The second is the practitioner's way — which is quicker, but less accurate; but usually good enough. This is to get right in front of the patient's face, and with the right hand enter the right wing of the tray into the mouth, as a farmer does the rails of his "bars" (gate). Then let go of the handle, and with both in- dex lingers spread the lips a little and look in. If we let go, the tray will drop down and center itself over the ridge, or place of the ridge, by cheek and tongue guidance and its own weight. We 11 examine its needs and take it out and expand or contract its wings, and turn its heels up or down till it approximately fits the jaw. >s"e\'er attempt to hold the tray down in place to inspect it, but let it seek its own po- sition, freed from cheek=and=lip hindrance. The next step, after fitting the tray by either method, is to TAKE A CORRECTABLE IMPRESSION. By "correctable" I mean one where no part of the metal comes in contact with the tissues of the mouth. We are going to correct up this impression by mouth and tongue movements on sensitized surfaces; but we couldn't thus correct a metal tray. Students and novice practitioners are ad- vised to take this correctable impression from the approximate model that they first fitted the tray to; then afterwards fit it to the mouth, as now soon to be described. To take the correctable impression from the approximate model is very simple. First rub the model well witli pulverized soapstone. Then make a little roll of warm modeling com- IX Dextal Prosthesis. 95 pound in your hands and press it carefully down onto the prepared model. Then press the fitted tray down onto the compoimd. ^V'hile we finger=})ress the compound around the edges of the tray to the model, we '11 not forget to turn a little of it over onto tlie hack, or reverse side, of the tray, and touch it with our finger, dipped in cold water, to clinch the tray and compound together. We have here now taken a correctahle im- pression of the approximate model; the next thing is to separate them. We must begin the separation hefore the impression material gets anytliing like hard. And right here is where some of the class may get things mixed up a little. Watch close and listen carefulh/! AVhile yet ^\•arm, we '11 dip the whole thing into cool water for a reri/ fete seconds, to chill the imju-ession a little. Xo. we '11 take it out and (|uickly pull it parthj loose from the model at tile heel: liurriedly re=dip it back to let the cool water under it; jerk it out and instantly re^press it back tightUi to the model; and stick it ])ack to /////// cool. After cooling, we "11 sep- arate carefully. If we at first let the compound cool fully without this precaution, we might find the sep- aration more difficult in some cases. And there are a few instances where we have to "core out" underscuts before taking an im- pression of a mold. In this, we simply first fill u]) the under^cut with compovmd, and cover it with tin*foil, and soapstone the foil; then go on and take the impression as I 've just described. Doctors, he sure you understand me in sep- arating an impression from a model, when we 96 Greene Brothers' Clinical Course wish to preserve the mipression, as we do in this instance. Don't attempt to take an impression of a model without first soapstoning, or otherwise creating- it, to prevent adliesion ; and then don't get your compound too warm — never hot. AVe now have a correctable impression from the approximate model (student's way); and are ready to adjust it to the mouth, in all its parts and points and details — ^^soon to be shown. But, before we show you liow to correct and adjust a student's correctable impression to the mouth, we must return to the practitioner's method and show you how we get said impres- sion directly from the mouth. The corrections, after taken, are similar in both methods. The practitioner's May is the shorter one. but not as simple nor as easy as to take it from the approximate model, outside of the mouth. And, only for the inconsiderable extra ten min- utes for taking the student's approximate im- pression and making the approximate model from it, I 'd always prefer the round-about way of getting the correctable impression. I have learned, mostly, to disregard a few extra minutes of work, for convenience, com- fort, better results, and avoidance of future an- noyance; especially in difficult cases. PRACTITIONER'S CORRECTABLE LOWER IMPRESSION. Our metal tray has been fitted to the mouth. (Index F.) Now we '11 take a small hand-made roll of wai"m c()ni])()nn(l — for a medium case, about one==foin'th inch in diameter — and place it onto, or into, the face of the prepared tray. (Tray should have some small holes through it, to help fasten the impression to it.) IX Dextal Prosthesis. 97 The roll is purposely an inch or more too long; so we '11 double the length^surplus over onto the back, or reverse side, of the tray, press closely, and finger-touch it with cool wa- ter, to prevent its dropping loose when we turn it over to take the impression in the mouth. The impression material being fastened to the tray and finger* fashioned ready for appli- cation, we now further warm it till quite soft, by x^assing it l)ack and forth over our hand-lamp flame. Before entering it into the mouth, we '11 look the i^atient straight in the face and say: "Madam, this is warm, but don't fear; it \\ill not burn you." This forewarning is often nec- essary to forestall a false suggestion of pain. Form you a habit of forestalling suggestion, and save both yourself and patient annoyance and trouble. And let this suggestion include the gratify- ing fact that you '11 not choke her — a popular fear of impression^takings. We are standing, or sitting, right in front of our patient, who is seated, preferably, in a common chair and in our impression^room, or cli'fui laboratory. Our small alcohobgas water- heater and all the rest of our needed conveni- ences are on our little table witli cleats around its edge to pre\ent things from slipping off. This little impressionstable, with its contents, is at our right liand and within easy reach. AVith our ])atient sitting up straight and liead in natural position, we hold our loaded tray by its short handle between our thumb and finger (right hand) and enter first the right- hand wing into the mouth; tlien push it to the right and enter the left wing. 171 98 Greexe Brothers' Clinical Course As soon as both Avings are well in, we '11 let go and instantUi spread the cheek-lips a lit- tle with our index fingers, both hands; that is, we '11 pull forward a little and spread lightly. Xow, right here, doctors, let nie, even in ad- vance, caution you not to make this lip-spread- ing "stunt" too roughly — as you '11 be apt to do. Practice it first on each other's mouths, take your scolding kindly, and profit thereby. This light spread*shaking of the lip=cheeks gives room, and our tray centers and settles down instantly, of its own weight, guided by the tongue and cheeks, to its proper place. It is in position. Standing, or sitting (I re- peat), right in front of my patient, I quicklij place my two index fingers on the wings of my tray and ^vave=press down gently and lightly: ahcai/s Ughtlij. (I expect to repeat several times in this Course that an impression should be taken at about the strain the plate is to be worn. A little reflection will tell you why.) When it 's down to place. I hold it there a few seconds to chill a very little. Xow watch close while I press the sides of my impression to place. I lay my left index finger on top of the left wing of my tray longitudinally — not c?'oss'wise. At the same moment I ])ut my left thumb under the handle — or, rather, lip — of the tray, to steady it, if needs be. While I thus hold the impression down with my left index finger, I run my right index fin- ger around on the lingual side (under the left side of the tongue) and press the soft, projecting compound under the edge of the tray, and back behind it, onto the condyle, and on the outside of it, over the masseter muscle — ^^well, all around the condyle lightly. IX Dental Pkosthesis. 99 Now, change hands, and in exactly the same way do exactly likewise on the left side. Get this all clear in niind; then we '11 go ahead. (Some one of the class is asked to explam this far; then we resume.) I '11 now hold the impression down ^^■ith my two index fingers, one on each side; and, wliile doing so, I'll straddle the cheek=lips (on both sides of the mouth) so as to get the cheek be- tween my indcw finger and my long nei.vt, "mid- dle," one. Observe closely: my jirst fingers are on the inside of the mouth, holding down the tray, and my second fingers are on the outside thereof. While I work down on the cheek, outside, with my long fingers, I also at the same time work down the outside of the under^lip, in front, with my tliumbs. Why. it seems as though our hands and fingers were made on purpose to take a lower impression in this simple, easy "Greene" way. Now, my impression is pressed down to place all around, on both inner and outer sides of the alveolar ridge, and also at the heels. But it presses too hard, probably, on the active mus- cles, especially the masseters. And now, here, doctors, is a pointer of great value to any extensive ])late=maker. A\'ith my front finger still holding the impression down, and the modeling compound still warm, I saj^: "]Madam. o])en and close your mouth and bite down on my fingers, quickli/:" As I gi\'e her the command, I look her in the face and kind o' obey it myself, to ])r()m))t lier movement. When she opens and closes her moutli and bites on my finger, the muscles aforesaid lift the material, projecting beyond the metal tray, up enough to give full relief from maximum strain, but no more. The contact is still enough that tlie little space between the lifted 100 Greene Brothers' Clinical Course compound and the flesh (niaximmn and min- imum range of play) will fill up with saliva, and thus make conditions for atmospheric pressure, or so-called "suction." After she has obeyed mj^ command and the strain is lifted from the masseters and condyles, with my fingers still on downsholding duty, I have her also work her lip and cheeks a little, to approximately relieve, maybe, other strained tissues; especially the levator labii inferioris. Then I give her another command ( for which she has previously been prepared, and instruct- ed to obey it) : "31adam, now squirt your cold M'ater into your mouth quickly!" This is from a httle syringe in her own hand; or in the hand of an assistant, if one is at command. It is to cool the imjDression. After a half^minute's cooling I remove my correctable impression from the mouth; and the whole procedure hasn't taken much, if any, more than a minute or two of time. But ^ye '11 look at it now, and see whether it is really a correctable impression or not. If, by some mishap, the metal edge, or other part of the tray, should show through, it 'd not be a correctable impression. The movements of the muscles can't correct metal. So, if any metal is in sight, we '11 just cut it all away with knife or file sufficiently, and trace compound thereonto; then it will be cor- rectable, by muscle=trimming. Well, we now have about what we 'd have had by the student's method, plus the approx- imate relief of masseters, just described. In either case, we are now ready to proceed to correct what, after all, is so far only a model- ing'compound tray. The correction will be the IX Dental Prosthesis. 101 transformation of this tray, bj^ detail, into a test^impression. You have now seen done and heard ex- plained the first step in a full lower modeling* compomid impression. To further impress it on your minds, some one of you may now read it as "Step No. 1," on this hst of printed notes, that each one of the class is to keep for future reference. (Later: This imntccl work will now, of course, supersede the former note system for reference. ) STEP NO. 2 IN LOWER IMPRESSION. "Trim it approximately tcith knife, leaving it a little too long, and fully deep." This consists simply of the warming of the edges a little over the s))irit'lamp and shaving off, with a sharp knife, what is evidently a surplus. Bear in mind, this knifestrimming is only a crude approximation; but about such as dent- ists usually depend on for exactness in the com- mon, old method of guess^trimming of plates. Well, now that our correctable impression is only a very little larger than the finished plate is to be, and will not distort the mouth hy its size, or depth, or length, we are ready to correct its center over the alveolar ridge; or where the ridge used to be, if absorbed. It may really be correct there now, but we don't know it; for it covered more area than we needed, and that may have strained and distorted what we do need. So we '11 go through the motion, and no harm ^\ill be done, anyhow. STEP NO. 3 IN LOWER IMPRESSION. ''Equalize the center by hot-stream, normal plate^ pressure, and icave'like motion/' 102 Greene Brothers' Clinical Course We '11 pour our tenspenny hot=stream from our little spout=eup into its center till it is quite soft — just on the safe side of the burningspoint» This softens the center well and deeply. Then instantly ^^e dip the whole tiling into hot water and out quichly, to mellow the edges a little, but very shallowly. Then dextrouslj^ but carefully, return it into the mouth (left side of mouth first) and as quickly wave*press down with our two index fingers lightly. We hold it down half a minute, when, more than nine chances to one, the pressure is equal- ized; if, indeed, it needed equalizing. But do this properly a second time, and it is sure to be — =which is to be test=proven a little later on. Of course all this has to be done quickly, or it will be a failure. It may take some prac- tice for some of you to do it quickly enough for success. As in writing, you first learn hoxo to perform these little manipulations and then how to do it speedily. One "D.D.S.," with a sigh, once upon a time voluntarily admitted he "wa'n't jitten by na- tur to do sich fine work and so quick." He'd "ruther practus his specialty an' pull an' plug teeth an' do crown* an' bridge- work." Ha, ha, ha!! Well, now, you may read your note again, as before, what you have seen done and heard explained, as the third step. I '11 only add that, if we took our correct- able impression by the practitioner's method, and carefully, it isn't probable any change has been made as to the fit by this equalizing step. But, if any at all, it isn't probably more than the thickness of the thinnest blotting*paper, at the most. An expert can do this by quick hot^^ IN Dental Prosthesis. 103 dipping the whole impression, instead of spout* cup pouring. STEP NO. 4 IN LOWER IMPRESSION. ''Bite on dummies, for jaw'rest" We will now prepare to very*edge the outer rim of our impression. As before, this muscle' trimming is done, again, by lip'and==cheek and tongue movement, on sensitized surfaces. To very-edge correctl}', and hence success- fully, the impression must surely be held down to place while the muscles do their trimming. This is absolutely essential; so we must plan to hold it down. And it must be down with- out our own, or our patient's, finger=help; for that would interfere with the normal action of the moving tissues that do the trimming. In- deed, the patient wouldn't make the necessary movement with my finger in her mouth. So we '11 put a jaw^rest on the reverse side of the metal tray for her to bite down onto, while she makes the scientific, automatic, self' trimming movements. See! I will take this little roll of warm compound, about three=fourtlis of an inch long, heat its surface on one side a little, and stick it onto my metal tray — the other side from the im])ression. I '11 i)ut one on each side, of course. They are "dummies." I '11 warm the edges of my dummies. "Xow, Madam: When I put tliis into your mouth, I want you to })ite dowii onto it quick- ly/' She gives one snap and my dummies have the marks of tlie u])])er teeth ((n- her gums, if slie has no teetli) on tliem. That is, we have had her "bite on dummies for jawiTst." So you now read "Step Xo. 4." after you 've seen it done or heard it all exj)laine(l in detail. 104 Greene Brothers' Clinical Course STEP NO. 5 IN LOWER IMPRESSION. '^Vcry-cdgc (musclc'trim) outer rim and Jicels, one side at a time, by szcalloicing and lip'and- cheek movements, ichde biting dozen on dum- mies." I ^vill, for instance, very-edge on the left side of her face first. I '11 warm the very edge of what is the right Aving of the impression when the handle jjoints toward me, and slip the opposite left wing (not warmed) into her mouth first; then pull lier left cheek over to her leftward, and enter the warmed edge last, without cheek interference. Immediately she bites down onto the jaw» rest (dummy) and swallows, and sucks her cheeks and works them energetically. In from fifteen to thirty seconds I have the outer side of my impression accurately trimmed, and also cut ofi^ — ^^or, rather, turned up — for the right length at rear. The deglutitory motion did the up=turning for the length of the coming plate. And it will be just this long, because the model from our up'turned lieel will make it just so. The length of a lower plate, same as that of an upper one, may be of exceeding importance. But, lest this first trimming may possibly not be all that is needed, I '11 repeat it till no further show is made by the cheek and swal- lowing movements. Do this righth% and j^our trimming will be exactly correct. Now, I '11 similarly warm the other side and oppositely enter it, and have the same move- ment made as before. And, if necessary, I '11 make a special trip into the mouth to partic- ularly muscle-trim the lower lip-strain by the movement of the levator labii inferior is — in Latin for short ! IX Dextal Prosthesis. 105 You well know how commonly this levator hreeds the Johnnv'jmnp^up malady in lower dentures. But this pesky lever is a wise me- chanical surgeon; it knows just where to trim a modelingscompound impression, or plate, if it has a chance. Well, we are done with the outer rim; let 's get to tlie inner one. STEP NO. 6 IN LOWER IMPRESSION. In the language of youY printed note, let us "Very - edge the inner rim and inner heels, all around at once, by sicalloicing and by vig- orous tongue movements, while biting dozen on dummies f' Since we are getting onto our job of sci- entific trinmiing, this is easy. I will this time warm the inner, or lingual, rim, and all around at the same time. But, as the muscles and glands under the tongue, that are to do the mechanical surgery, are often Yerx lax and soft and weak, we must now have our inner rim quite soft indeed — ^just a few degrees on the cooler side of the scorching-point, in some cases. After blistering your o^^n mouth, and es- pecially that of your patient mother^iu'law a few times, you '11 learn to make this fine line of thermal demarkation to an amazing nicety. (Don't shudder at this prospect of vivisection in the interest of prosthetic dental science.) You must learn to musclestrim the lingual rim so it will safely set down, without strain, in- to the su])=lingual saliva pool, to give it suction. To my patient: "listen, ^ladam, to what I 'm going to say. The instant I slij) this edge^ warmed impression into your moutli. I want vou to bite down on our dummies and szcallotv. 106 Greene Brothers' Clinical Course and throw your tongue all over your mouth as vigorously as you can. Act quickly and fast!" (Better, in some cases practice jNIadam a little, in advance, in the movement.) She has obeyed; we '11 leave the impression in a few seconds to cool and then take it out and knifestrim off the turned=up edge, or a part of it. We '11 use common sense and simply repeat what we have done till no more sur- plus turns up by the same energetic action; then we '11 have an accuracy of trimming not to be reached in an hour, or a day, of trials by guess ^trimming off a plate after it 's made. You say: "All this is migthy particular work." Of course it is; but, after all, not more so than many other things you liave been do- ing. Xor is it as particular as what your wife has often to do when she picks the naughty motes from your eyes. Can you afford to be as skillful and as art- istic in your boasted j^rofessional manipulation as your chiropodistic artist has to be? If not, better turn your impression=taking over to him. He is used to being "particular" in Jiis work. But, seriouslj^ it will not seem to be so when you get accustomed to it. STEP NO. 7 IN LOWER IMPRESSION. ''Conform lingual side hi/ steady tongue'press- nrc, and cool well in place, rcith si/rin^-e, through 7iotch, rchile biting down on dummies/' By conforming, you know, we mean warm- ing slightly and pu.shing to place with steady, gentle pressure, and cooling while under such pressure. To press^to and then remove and let the material rebound wouldn't be conforming worth a penny. IX Dextal Prosthesis. 107 It must be at least fairly well chilled Avhile in place, under gentle strain, and then well cooled before removal. Don't tire of this repe- tition; you 11 "need it in j^our business." But let us go on and conform these lingual sides of our impression. In our sub ' lingual verj^sedging we prevented air from passing in and out under the lingual edge, by its reaching onto and into the sub'lingual saliva pond. But there is room for some, and is already some, behind it. So we must get that out; or, rather, we must have our patient do it. Before we put her at it, we '11 cut a little notch in the dummy, on the left side of her face, so we can squirt some cold water under her tongiie, through our syringe point, to cool the compound, while under pressure. I repeat: "Xoiv, Madam, listen to ichat I'm going to ask you to do. As soon as I place this into your mouth, I Mant you to push it up close against your gums with your tongue, using gentle, steady pressure. Push all around and hold it to place till I can scjuirt some cold wa- ter through this notch and thoroughly cool it." This she will easily and readily do. Her soft tongue will give an even, equalized pressure on the harder and the softer parts, nearly the same. I will here remind you that we are now tak- ing this part, as we have taken all other parts, at about rightsangle pressure; which is almost essential in modeling^compound manipulation. Plaster of Paris (by the '"pass^word method" only) pushes in all directions alike, and thereby equalizes. But modeling composition — the best of it — ^^liasn't nmch flowing quality, at a suffer- able temperature; therefore it must be pressed at right angle against tlie soft places, which yield according to their needs. 108 Greene Brothers' Clinical Course All right; we 've now so pressed the lingual side of our impression and cooled it through the prepared notch. Xow, we have valvC' pressure on all the soft parts, so air can not pass, unless our impression (or plate) is moved by force; and this common force has been prevented by muscle=trimming. We have here done a most important thing in making a lower plate — 'Conformed it to the lingual side of the alveolar ridge, assuming it has a ridge. STEP NO. 8 IN LOWER IMPRESSION. "Take impression of fraenum by quick Up' licking, and re'touch "while holding down with both index fingers. Dont bear hard nor press downward when re'touching." Just before warming the spot of fraenum contact on the lingual rim of my impression, at the side of my small spirit'flame, or with my mouth blowspipe, I say: "Mrs. Jones, I 'm go- ing to hold this impression do^vn myself this time, with my forefingers, so you can use your tongue quickly and freely. Immediately on this going back into your mouth, you will please lick up under your upper lip vigorousty, and quickly draw your tongue back to its place." In doing this, when the material is quite soft, she simply muscle=trims out room for the fraenum to move freely in, when she licks her lips, in wearing the plate. For, of course, again, the plate is to be a duplicate of the impression. But, as she may trim out a little ioo much, so as to leave a little leak (at the sides of the frsnum) , I hurriedly dip my finger in cold wa- ter, and reach over under her tongue, and gen- tly pull back what may have been overdone IN Dental Prosthesis. 109 by the muscle itself under too vigorous tongue movement. She musn't loll her tongue out, lest she fr^numizes too deeply and gives relief xiith a leak. I will here give you each a sample retouch in your own mouths, using a different finger, of course, in each case. You feel my finger pressure is light, but steady and not downward. Should you use much force in retouching, you 'd undo what you 've aimed to do. You merely need to pull back to place a "leetlc" compound that may have been pushed off from the ridge at the sides of the frsenum, so as to stop the air^leak. STEP NO. 9 IN LOWER IMPRESSION. Here is j^our note : ''Test for fit. Dip the impression in cold wa- ter; place it in the mouth; and hear down with index fingers firmly for half a minute. If it sucks fast, or even if it comes loose with a little noise, it 's O. K. — not otherwise. If no blunders are made in following up all after-work, the plate, after it settles, will always fit even better than the impression tests." Any perfect impression, on a ridge of almost any size, will have more or less so-called suc- tion after pressed down a little wliile. And any impression ought to have a little of such, though not always enough to hold it down much. Nor is it at all essential tliat a lower plate should have strong suction. Even though it should stick tightly (as most of them will for a while), the tissues will, in time, be absorbed and tlie ])late lose its down'hold. (We "11 liave a "Joker" substitute for a low- er suction before we are done witli it.) 110 Greene Brothers" Clinical Course But in any test I want at least to hear the impression make a Uttle "squashy" noise in working it up and down, by its short handle, as proof that I have a fit. If it didn't make any noise, I 'd conclude I hadn't the best fit that could be made. So I 'd set about for an improvement. I 'd not take another impression, however. If I were to make one hundred sets of teeth, I 'd take but one impression for each case And I 'd correct each one till I got mv desired test. If this one doesn't test, I will resort to Step Xo. 10. STEP NO. 10 IN LOWER IMPRESSION. A REVIEW STEP. This, if needed, would be a review step. I would first trj^ the conditions of Step No. 9 again. Then, still failing, I 'd repeat the op- eration of Xo. 7; then Xo. 6; and then Xo. 5, in turn (in their backward order), till I found the fault somewhere. But I 'd look especially after the masseters and lower^lip strain; not forgetting the sub' lingual tissues, in case of flat gums. But in cases of much alveolar ridge I 'd rather expect to find the defect in poor conforming of the lingual edge of the impression to this ridge. But, anyhow, doctors, I 'd not take another impression: and then another and another, af- ter the old way. I 'd adjust and correct up jjarts of the same one in detail until I got a iesf that would, in advance, warrant a fit of my denture. Then I would polish its edges, if not its entire surface, over a spirit=flame; and go on IX Dental Prosthesis. Ill and make a polished model that would mold, or swage me, a duplicate, almost finished, denture. If of plaster, this model is made, of course, by the "full saturation" way of mixing and pouring. That is, the correct quantity of pure, teind water with the right amount of good plas- ter, mixed thoroughly but quicldji and "poured," or placed, before it begins to harden. To impress an important point. I '11 repeat: Stirring plaster (or any other crystallizing sub- stance) after it has commenced to set much, breaks the forming crystals and causes rotten- ness of the ])roduct. A PLASTER LOWER IMPRESSION. If for any reason, real, imaginary, habitual, or otherwise, I sliould want a plaster impres- sion, I 'd now use this completed modelings com])ound one as a tray to take it in. I 'd pour some very thin, creamlike plaster (impres- sion plaster) into it, sling it mostly out, and take my ])laster impression qiiickl// with light index'finger-pressure and wave=motion. The wave^motion is to cause the better flowing of the ])laster. At the same time I 'd have the ])atient go on and repeat all the lip-and^cheek manoeuvres she had made on tlie compound; and especially bite down a little on my fingers to provide for massi- ter u]>lift in action. That is to say, the muscles would ])us]i the plaster out and ])revent strain there. If any careless excess of plaster should over- flow the muscle=trimmed edges of my compound tray, I 'd rub it off ])efore making my model; and use tlie modeling^comjXJiind edges as my guide, botli in ]K)uring, and trimming my model. 112 Greene Brothers' Clinical Course But, doctors, there would seldom be any- good reason for the plaster; for I couldn't im- prove such an impression, even technically, un- less I could confine it (the plaster) and employ the conditions of the "pass^word." (Index P.) Still, as it requires less skill to equalize with cream=like plaster than with tlie spout=cup, it 's the best way for a novice — after the modeling'' compound impression has been otherwise finished. The making of a model here would be the same as in the upper case, whether I used all plaster, or my non-changeable approximates, and faced them with plaster. But I 'd make it, in either case, immediately after getting a satisfactory test of my impres- sion; or else keep the impression in cold wa- ter till I could make it. (Another point that '11 bear repetition.) And though "this is neither the time nor the place" to give the valuable secret, I can't forbear to tell you it is best always to make a plaster model as thin as \^ou well can; or at least trim it down thin after it is made. Then use metal, or other non=changeable plates of some sort, under it, when necessary to raise it up in the flask, in packing. This, doctors, is a ]3ointer worthy of a gold* plated safetyspin in it. You have doubtless spoiled many a case, as to its fit and occlusion, one or both, by putting worthless, mushj" plas- ter under your plaster model, to raise it in your flask. Have you ever thought of it ? Doctors, think! This all, however, more properly comes up in our "third degree," when the whole model' smashing matter will be reviewed. IN Dextal Prosthesis. 113 PARTIAL LOWER IMPRESSION. This is, to some extent, a repetition of the principles involved in the full lower; but it takes in still more. We ^\dll first take a case of, say, six re- maining" anterior teeth. I prefer a tray with a metal*closed space, or place, for the natural teeth to project into; but open ones can be closed with modeling coinposition. See, here is a common, ridiculous, long' handled one that we '11 trim up and down. We '11 "transmogrify" it, as some call my bold surgery on the old-fashioned trays. We '11 cut off the long handle to, say, three* fom-ths of an inch in length and hammer it (the shortened handle) down thin to get rid of tipping weight and inconvenient bulk. We '11 further trim down its sides and cut it off at the rear, the same as for a full lower; and especially trim it off clear down to the handle in front. This last in order to take the impression of only the ends of the front natural teeth on their outer surfaces. We '11 want to change this impression off= and^on; so we want room to look under and see the teeth properly re-enter into their re- spective sockets in the compound. (We have recently perfected a set of trays, including this needed one, with removable han- dles; manufactured by the Detroit Dental ]Man- ufacturing Company, Detroit, ]Mich.) As the natural teeth here act as guides, to prevent side=sli})])ing, it is even easier to take a partial impression than a full one — in model- ing compound. ^Vfter the tray is center^fitted over the teeth and alveolar ridge, as in the full case, we '11 18] 114 Grekxe Brothers' Clinical Course take a roll of material from our hot=waterspan and shape it into place ("fashion" it) in our tray, as we did before in the full case. We '11 now warm it over our hand=lamp flame, as in the full case before. And we '11 take this partial impression in every respect as before in the full case, through to the finish of it. All that was shown you in such detail as to hardly need repeating in the partial case; pro- vided the teeth are so shaped and stationed as to let our impression in-and-out of the mouth without "drawing" In fact, in an easy case like this, it requires but a very few steps in* and'out to do all I have told you and shown you. We are almost certain to get a correct im- pression of the alveolar ridge every time. So the most there is to it is the muscle=trimming for relief « room, especially at and about the heels; and the conforming on the lingual side. H die j 'Without'} eak — and the story is told. "Yes, hut" emphasizes one of you, "what about leaning teeth and bell-shajDed crowns, where the compound must draw, or it '11 not come out?" MODELING=COMPOUND IMPRESSIONS WITH LEANING TEETH AND BELL=SHAPED CROWNS. Well, when we have the right sort of mod- eling compound and know how to use it, that once vexing problem is easily solved. Then the old bugaboo vanishes. Then it is very mucli easier to take such an impression in compound than in plaster; that is, plaster in the old way. The best old way, however, is new to a ma- jority of dentists. The common old plaster way is to take the impression, teeth and all: remove the tray and IX Dextal Prosthesis. 115 break the plaster adhering to the teeth all into uncertain pieces, in the mouth; then take pieces out and stick them back together — ^^and make the model. That is hard on the patient; besides, all the trimming of the plate afterward is by guess* work. Even if using all plaster, I have a decided improvement on this old pull==andspush way. I make the plaster break easily and just about where I want it to. I simply place layers of thin tin-foil where I want the plaster to break. I drop the little foil flakes in while I 'm filling the tray. The foil will make a seam in the plaster just about where I want it to break apart. Then a little thin cement, such as we use in temporary fillings, will unite the pieces of our purposely'broken impression to perfection. The Detroit Dental ]Mfg. Co. make a plaster^ cement purposely for mending broken plaster. But I can take the impression of these lean- ing teeth and bell-shaped crowns just as well with modeling compound, and then have the benefit of my accurate muscle^trimming, ^\'hich is impossible with plaster by the old way. Biitj 7iozi\ hotv to do this. CORING OUT FOR UNDERCUT IMPRESSIONS. I first carefully ])ress enough compound around the teeth to build them out to cone* sliape, instead of under*cuts. Then I cool it after in place; varnisli it to hold tin*foil; stick on some foil and dust it over ^^•ith powdered soap- stone. I then treat these cored=out teeth just as if they were nafiiralh/ cone-shaped. I go on and take my impression o\'er the cores to the fin- ish, same as in our simple case, just described. 116 Greexe Brothers' Clinical Course When my main impression is m u s c 1 e = trimmed and conformed on lingual side, and out of the mouth, and so forth, I cool my cores, still in place around the teeth, VLell; break them away from their x^laces; take them out and put them where they belong in the main impression. Then I make my model, preferably using my non=chargeable approximate, to provide against changes in plaster and in my dentures from jjacking, vulcanizing, and cooling. ■'But," you ask, ''how are you going to get your })late into place, when made?" Well, doctors, tliat 's your job — not mine. I 've shown you how to take your impres- sion simply, accurately, and with a minimum annoyance to your patient. If you have a case of uiider=reach wliere the plate cant he entered as a farmer enters his slide-bars in his gate* way, one end at a time, you 11 have to cut away some, of course. But be careful ichere you cut. and cut away no more than necessary. That "s all you can do, tliat I know of. Doc- tors just set your brain machinery to harmonize Avith your sul) - conscious genius, and answer your own (juestion. and be glad. But, after all. doctors, a perfectly fitting denture, rightly adjusted to the muscles, doesn't need to lit close against the teetli at all points, if, indeed, at any point. If strained, such teeth soon give way for relief, anyhow. So we don't depend on a fit against the teeth to help hold the plate very long. Such help is beneficial only in lielping liold the plate in ])lace till it adjusts, or imbeds, itself. As for clasping the plate to the natural teeth, I quit that thirty years ago as unneces- sarv, when not reallv harmful. Still I concede IN Dental Prosthesis. 117 there are partial cases, where the alveolar ridge has no up'turn at the rear, where the telescope^ crown scheme is useful; that is, where we put on a permanent crown on a natural tootli and then attach a telescope crown, or band, to the plate and slip this latter crown, or ring, over the first one. But to cut down any sound tooth to crown it for any purpose should be a last resort. Also a little extra weight is frequently a good thing — ^^mainly to hel]) hold it down to place while it imbeds itself in soft tissues. But that will come up and be explained in our third lecture. I am now on lower impression. If you care to take a plaster partial (which is seldom sluj advantage where the modeling compound is taken properly), you can take it on the compound one, by means similar to the "pass'word method" in our first lecture. (In- dex P.) But, as there is no way to confine much of the cream- h'ke plaster, the main point in the "pasS'Word" scheme is wanting; so the "equal- izing" (the only possible purpose of the plas- ter) will not probably be much improved. But, should you equalize with "cream-like plaster in ready flowing condition," rub the overflow, if any, off of the edges before making the model. The compound has been muscle* trimmed, and is adjusted to the movement of the tissues. OLD=TIME IMPROVEMENT IN ALL.PLASTER LOWER IMPRESSIONS. And should you, foi- ()ld=lial)it's sake, wish to take a full lower al]=plaster impression, let me suggest hoxc to do it. But you needn't bother about telling those happy old "plaster fiends," 118 Greene Brothers' Clinical Course who are sure they "already know" enough. 1 know their self-satisfaction tcell, for I sat be- side them in the old stage=coach for years, re- fusing to be unsettled myself. ]Maybe better let 'em enjoy the pleasure of the gambler's chance of hope=and'doubt that always goes ^\•ith guess=trimming and guess* scraping for relief. But, for your more modern selves, use our old-time imjJi'ovement on the old, tissue=straining way. That is, we "transmogrify" our metal tray and fit it to the mouth, as I have shown you, to a size no larger than the plate is to be. You, of course, understand the tclifj of a shallow tray. We '11 now punch some holes through it to clinch and hold the plaster. We '11 trace a table^spoonful of soft plaster along on the limit- ed tray and take impression by tremble'pressing down very lightly with our two index fingers. We '11 look over into our smooth earthen bowl, and, when the remnant of plaster there- in has just begun to set a very little we '11 tell our patient to close her mouth, bite on our fingers very lightly, swallow, suck her lips, and work her cheeks mildly — and do it all quickly and stop. When she has done as told, I hold down the impression steadily (or, better, have patient hold it down with index fingers) till the plaster is hard in the cup. When I take it out, I '11 find the plaster cracked around the edges of my tray, and lifted uj) behind the back ends of its wings. We '11 trim off to the crack, and Ave'll have the most com- plete all^plaster impression possible. The moving tissues have cracked the sur- plus material at the edge of my narrow tray IX Dental Prosthesis. 119 and told me about where to trim it to for relief. We can even apprOiViniately test this im- proved allsplaster impression, provided we have no long, heavy handle to tray to tip it over. To make the test, we '11 do just as we did a while ago in our modeling-compound impres- sion, in Step No. 9, of the full lower case (p. 112) . Of course, it will not stay down as our modelingscompound impression did, because of its imperfect, file=guess trimming. But it zdll tell us just about how a plate from it would stay down, at the start, anyhow. Of course, it would stay down better after worn a while for adjustment. To some of our old plaster friends, this im- provement would be worth only 98 cents be- cause it would disturb their pleasures in trim- ming by the old college^gag instructions: "Trim till you tJiink you 've spoiled it, and then more till you are sure you 've spoiled it — and then some." And worse still, doctors, it would steal from them some of the sweets of the guess-gambling luicertainty in plate*work. Yea, doctors, yea, even this iniprovement ^^ould rob some of the "best men" of their names at the head of journal articles advis- ing "Only plaster for impressions"; because it would timely lead them entirely away from plaster at all — in lower impressions, at least. Better let 'em go on with tlieir long, deep, and longshandled trays, and their five*])ound thumb=pressure that distorts the mouth all out of shape, so they can trim and trim, time after time, with gambling*feature ecstasy. Then in the end, to dismiss the case with multi*assur- 120 Greene Brothers' Clinical Course ance to patients that "lower plates don't stay down, nohow." But as for yoiu'selves, doctors, practice these things, first a little in your oAvn "oral cavi- ties," then in the mouths of your forbearing mothers=in'law, "sisters, cousins, and aunts"; and announce to nauseated humanity that you don't need to use plaster in mouths at all. Or, to be "ethical," get your patients to tell it around as a secret that you no longer need a half'gill of mushy plaster in a 3x3 tray to choke'gag people, by forcing it dow^n their throats, like cramming geese to fatten them. Doctors, please pardon this outburst of im- patience with these over-sized trays; over^bulk of material; and over=strain in needlessly dis- gusting patients, in taking impression. It 's worse than mal=practice; for mal^practice may have the apology of selfish motive. IN Dental Prosthesis. 121 Fig. 13. Fig. 14. ,Fig. 15. Fig. 13. — Modeling-compound impression as usually taken in common deep tray. Plate from it would have to be guess-trimmed to fit straining tissues — difficult if even possible. Fig. 14. — Same tray cut down and fitted to the mouth. [Mod- eling-compound impression (same mouth) just as taken by the 3reene muscle-trimming method. No trimming of plate after made. Fig. 15. — "Correctable" (approximate) modeling-compound impression, taken from model, ready for re-taking and adjustment to the mouth. (Student's method.) [Cuts represent three-fourths of full-sized impression.] 122 Greexe Brothers' Clinical Course TO REFIT A VULVANITE LOWER PLATE, TEMPORARILY. You should keep on hand a supply of thin M'afer sheets and various thicknesses of this "Perfection" material. To prepare it , you press it out on a smooth, wet surface, prefer- ably of glass or marble. AVarm it in a com- mon tin pan and firmly slide^press it out with a smooth bottle or tumbler, also wet. But it is now furnished by the Detroit Dental ]Manu- facturing Company, of Detroit, ]Mich., ready for use. A 2:)atient comes to your office, maybe when you are busy at your chair, and insists that her teeth be ''tig-htened, somehow." You say to your patient in the chair: "Keep your seat and read this little article in the paper, three or four minutes, while I refit the old lady's plate." Seat the complainant in your impression^ chair. (Maybe blindfold her, too. lest she may learn too much about refitting plates herself.) Wash her plate clean Avith a stiff brush and dry it thoroughly. (This may be the biggest sec- tion of the job.) Heat a thin wafer sheet and stick it on till it perfectly adheres to her plate. It must actually adliere, and not mereh^ stick. And it must cover the entire surface of the plate, too. Then add another thickness onto the first. You can't stick a single thick piece tighth'' enough. When the second piece adheres to the first all over, dip the plate into hot water a few seconds, and have her bite down into it quickly. That is, to take her own impression. It may require a second heating and bite* doAAii, M'hen the plate is refitted — probably to fit as well as it ever did, possiblj^ better. IX Dextal Prosthesis. 123 "Call again, ^ladam, if it loses its fit in a few days or weeks. I '11 then have more time and will refit it permanentl3\" This is a temporary refit, the like of which I 've known to continue for several months. But don't neglect to caution lier not to wash her plate in hot water. She maybe returns in a few days or weeks and wants the plate refitted again. This maji require only re*dipping and biting again as be- fore; but you may have to dry and add an- other wafer, as before. Your judgment will guide you in it. TO REFIT A VULCANITE LOWER PLATE PERMANENTLY. To do this, you file the rim of the old j^late, including its heels, ofi' down to where there is no under-cut left. Place a wafer of compound in it, and add fully enough to restore the miss- ing rim and heels. The material for restoring the filed*off rim may be traced'on, as hereto- fore shown. Xow dip tlie whole thing into hot water, for an instant only, and have her take her own impression by biting lightly into the old plate. As tliis is to be a permanent refit, better soften and bite twice to make sure of a correct im- pression. The second time you '11 re^heat by liot stream from your s])outscup. Xow you have yoiu' impression in the old plate. Go on and very-edge the outer rim, and then the inner rim: and then conform the lin- gual rim; and then take tlie impression of the fnenum A\itli essential quickness. In short, do it all just tlie same as I 've sliown you in case of a regular lower impression, only she takes lier own impression by biting down. 124 Greene Brothers' Clinical Course In case you need to lengthen the lower teeth {i. e., open the bite), you simply use a thicker sheet of compound. And, while it is warm, have patient bite down, slowly and lightly, till the teeth show, or the features show, just as you want them to. Of course, if the teeth need changing in their position, that must be done first of all. (See "Refitting Upper Plate" in first lecture.) You have now tested your fit and in all re- spects have fashioned your denture to suit you. Flask your case, teeth'points downward. But (to repeat) don't put rotten plaster under it to raise it up in the flask. If it needs raising, use some non = changeable substance, like metal, crockery, or glass, to avoid mashing, which might change your articulation. Of course you '11 use the Greene Occlusion Retainer over the ends of the teeth before investing. Trim off and varnish your plaster invest- ment, or bedding, as usual. Fit the metal edges of your flask together, so there will be no ti23ping nor rocking. This is to avoid change in articulation, or occlusion. 'Now fill your "double" flask; the impres- sion first, and carefully, to avoid air=bubbles; seeing there 's no water in the impression, too. If you use a Greene non-changeable model, insert it in the impression according to direc- tion for their use, before filling the full flask. When the plaster in the flask is hard, warm the case slightly over dry heat, and open — ^^at the heels, of course, first. If you have properly soaped'stoned or pol- ished the impression and it was dry when you poured the model, the latter will come out whole and smooth. But, should it break, just mend it IN Dental Prosthesis. 125 with any tooth=filliiig cement and go ahead, as soon as the cement is hard. Never, I say again and again, vulcanize against plaster. But cover your model witli tiu'foil, or other metal, or with Uquid silex, diluted with water, about half=and=half ; then smooth it with soapstone powder, well rubbed on. If you have provided small vents for the escape of a possible little bit of surplus vid- canite, your model'holding half of the flask (at your right) is ready for use. Xow turn to the plate^holding half in front of you; warm it slighth^ and remove from the old plate everything and all that constituted the impression. Then scrape for a new, clean exposure, all over flic plate's surface. Xote the direction, ''all over." Pack evenly; flask witli little strain; vul- canize ])r()])erly; cool slowly and thoroughly; then take out your almost finished work. There are other ways of refitting plates, but none tliat embrace tlie Greene nmscle'trimming, valve^edge-fltting, and the like. They all have their defects and their objections. The impression = paste methods, the latest fads, are (]uick, but faulty and very incom- l^lete witlial. Tliey are fauliif, in that they don't take equalized impressions, even as far as they reach. Tliey are incomplete in that they don't extend the ])late at any point and tlius don't refit, where lies nine^tenths of the lacking. Xor in lower cases do tliey even en- able the widening of the bite and lengthening of the teeth, so often needed after alveolar abs()r])tion. Their only advantage is a little saving of time, provided Ave wanted to cover only their 126 Greene Brothers' Clinical Course limited ajjplication, with incomplete results. Their application is limited to only kind o' re- fitting the main contact surfaces of vulcanite plate. Why not refit it all, and, if necessary, extend its area while at it? I say this with regret, for I 'd slop clear over with congratulations at the feet of the in- ventor of any vulcanizable preparation that 'd enable the taking of a complete test impression in an old plate. But so far that has not been even approximated — nor even attempted, as far as I know. But, after all, why refit more than tempor- arily at all? It takes but a very few minutes more time, and a few more cents expense, to du23licate anew the plate wholly, than to refit it properly and permanently. And as for the fee, you can always get a few more dollars for the few minutes extra time and the few cents extra expense, for the all'new material denture. After you have your contract to refit the old plate and have begim your A\'ork to hold your patient, honestly inform her that re* vul- canizing always deteriorates and weakens old jDlates. And that it would cost her but a little more to use all=new material, ^^llich you can warrant not to break. Good rubber ])roperly vulcanized against metal won 't break. Indeed, if your fee is at all fair to your- self, you can afford, in selfish interest, to use all^new material, anyhow. And here 's the way to do it: RENEWAL OF RUBBER LOWER PLATES FROM OLD ONES. We proceed in all steps just as we do in permanent refitting, clear up to the time we begin to clean out the old plate for packing in the vulcanite. IX Dental Prosthesis. 127 Then and there, instead of removing the impression material and scraping out a new- surface for the refit=packing, we heat the case hot, over a dry flame — a gasoline stove, for in- stance. AVhen Jiot, we take a suitable instru- ment and, beginning at the heel, lift it all out; the old plate, teeth and all, together. Some of the plaster investment around the teeth will flake loose; but we '11 quickly ce- ment the pieces back into their places, and for- get them. Then we '11 oil the teeth and re- move them from the old plate, as in the upper case, before described. (Index R.) Then care- fidly replace tliem back home. In rare cases, we may need to cement the teeth l)ack into their places in their imbedment, to hold them while packing around them. Now we '11 cover the model, and all other plaster exposed, with tin-foil (Xo. 4). thin silex, or collodion, and pack and vulcanize just the same as if we were making an original, new plate. In fact, when done, we have made an entire, new plate, in connection with the old teeth. And we 've done it in far less time, and with far less work, and also much less an- noyance to the ]3atient, tlian to have made it over by the usual metliod. The right amount of rubber can be ])rac- tically ascertained in different ways: as by the usual ways of weighing, or measuring in water. But a simpler way is to take the base-plate (or im])ression material in refit and renewal cases) and roll it out into a slieet the thickness of the vulcanite sheet we are going to use. Then lay the sliect of base-plate (in this case, modeling comijound) down onto the vidcanitc sheet and scribe it, and cut off to the scratch. 128 Greexe Brothers' Clinical Course Then cut the vulcanite into suitable pieces and add, say, 4 per cent extra; and go on and jDack into place. But, as guess=work is especially unreliable and objectionable in lower cases, it 's best to use the cloth, as described in our first lecture. (Index C.) Of course Me 11 not tin^foil the model until after the cloth has been used and dispensed with. But during the use of the cloth (which shouki still retain some of its starch) the model should be treated to powdered soapstone, well rubbed on, to prevent adhesion of the vulcanite to it. The tin=foil on the plate after vulcanizing is readily removed with mercurial paste. (In- dex M.) Bear in mind that in thus renewing plates you can correct any fault that existed in the old dentures, either as to lit or occlusion, or both. Probably you will prefer to take the teeth off of the old plate and replace them (reocclude them) with sticky wax before taking the correct- ing impression. In that case tlie teeth, in sep- arating the flask, will remain in their imbedment instead of coming out on the old plate. In removing teeth from a \Tilcanite plate I prefer the ])lan of first oiling them and heating them one at a time with a mouth blow=pipe. WEIGHT IN LOWER DENTURES. You have asked about the weight of lower plates, weighted rubber, etc. Well, in some special cases, limited weiglit is a mighty good thing, though hobby=riding and over-doing have brought tlie practice into less tlian former use. If I were taking impressions and using plas- ter models and making plates generally by the IN- Dextal Prosthesis. 129 old ways, I 'd still do as I used to do: weight down a good many of them. But now, by the new method, it is far less frequently needed; the weight being mostly to hold the plate down till the floating tissues ad- just themselves to it. Xo use to try to weight against straining muscles. While I have other means than weight to use instead thereof, which I '11 give you later on, I 11 now proceed to show you how I weight down a rubber plate to the exact amount, and at the exact place. I may want it. TO SHOT=WEIGHT AN OLD PLATE. To do this, we 11 go back to our refitted lower plate. When we get ready to pack, we '11 stop and take an engine-bur and cut out all but a mere shell of the rear half of each wing of the plate that ue are refitting. This is to be filled with the finest "'mustard'Seed" or "dust" shot. To prevent the shot from running out, we '11 place across the back end of this excavation a piece of rubber, preferably weighted rubber; then pour in the shot till nearly full. Over this bird - shot we '11 place another piece of weighted rubber; then go on and squeeze to- gether, vulcanize and finish as usual. When taken out of the flask, we '11 have a refitted and weighted plate, all finished but a little final polishing: which we "II quickly do,' while rejoicing over the knowledge of our new, simple, practical weighting scheme. TO SHOTWEIGHT A NEW PLATE. Having thus sh(^t=vv'eighted an old plate, now let \s weight a neic one, similarly. We're ready to pack our case. We "11 take a little strip of weighted rubber and wrap it around a goose* [91 130 Greexe Brothers' Clinical Course quill, or some other small, tapering thing, and knit the niblier edges together, so as to have a weighted-rubber tube, when we slip it off. We \\ pinch the smaller end and have a tube, the larger end open. We '11 fill it with the smallest of bird^shot and pinch the other end. This gives us a weighted = rubber bag filled with shot : which comes witliin about five per cent of solid lead in weight. In packing we '11 first use the best of vulcan- ite around the pins of the teeth, or in the holes, if pinless teeth. Then we "11 lay a sheet of weighted^rubber on either side; and then place our bag of shot down hctzcecu the two side blankets: then go on and com])lete the pack- ing with weighted=rubber, and vulcanize and finish in the usual way. But use only the best of rubber in front, where the plate needs all strength possible. Xo weighted rubber there; nor any more ])ink rub- ber than actually visible in wearing. Xever face with pink rubber any farther down from the teeth than is actually seen; that is, if you wish to be honest with the wearer. Xot one lower denture in a dozen indicates ])ink rubber in front. And use either pink rubber or weighted rubber in thick lower plntes to prevent porosity. TO STRENGTHEN LOWER VULCANITE PLATE. Lower plates, cspccialUi icJwii vulcanized in the usual hurried, careless icai/, should not only contain the best of rubber, })ut should be addi- tionally strengthened in front with appropriate metal. This is on the market and should be used — unless the very best of rubber is used and vulcanized at the lowest temperature and long enough, and left in the flask cooling long IX Dextal Prosthesis. 131 enough to gi\e it the cow^horn texture and .strength. MIXED LOWER PLATES. It is sometimes an advantage to make a lower phite wliolly or partly of heavif molded metal: zchollif when a maximum of both weight and strength are needed, with a minimum of ))idk; and parti ii when a maximum of weight ttvV// a mniimum of bulk: and partli/, again, A\hen a maximum of weight zcitli a minimum of bulk at one place and a minimum of bulk with a maximum of weight at another place. For instance, a few years ago I had a case where the natural teeth were all missing from and including the central incisor back, and all the ridge gone, on one side, but all the teeth remaining and healthy on the other side. The teeth were missing on the left side. Here I needed bulk on the side where the teeth were to be put in, and a small but heavif flange to run around on the lingual side of the natural teeth to balance the artificial teeth on tlie opposite side. I had no chance to crown nor to clasp witli- out sacrificing one or more healthy teeth, whicli I didn't want to malj^racticingly do. So I first cast a heavy metal plate to go all around on tlie alveolar lack=of=ridge on one side and to fit against the hngual side of the nat- ural teeth on tlie other side of the mouth. This heavy plate, small in l)ulk, fitted up fairly close to. but not quite touching, the nat- ural teeth: and also around behind the wisdom* tooth, resting tliere on top of the gums. I used vulcanite (for bulk) under my artificial teeth on the heavy cast plate. 132 Greene Brothers' Clinical Course The cast'inetal flange on the opjjosite side balanced the artificial teeth, and it was a suc- cess; though others, and I, had "signally" failed by other methods before. Yes, weight, under some circumstances, is a good thing; indeed, sometimes by the old method of guess=file=trimming, essential for real success. But fortunately, I 've invented a "Joker" that will, by our methods, nearly always super- sede weight. I am pleased, however, to acknowledge a new invention by "Dr. Gilmore of Indianapolis, Ind.," known as "Gilmore Attachments" for holding plates to place where there are good teeth or sound snags to hitch to. It is excellent. (They are on the market bv tlie Detroit Dental Mfg. Co.) Dr. Gilmore has taken the Greene verbal course and of course takes liis impressions and occlusions by the Greene Methods. SWAGING LOWER PLATES. I have no improvements to offer to the best modern methods of swaging lower plates; ex- cepting that in the use of modeling*compound impressions I 'd use the Greene a])proximate non-changeable model, faced with an equal mix- ture of the best Portland cement and plaster,, well ground together in a mortar before the mixing. Pouring very low^fusible melted metal into a modeling*compound impression is possible if the impression is very cold and the metal at its lowest fusible temperature, but it requires care that some dentists won't be guiltj^ of. The agents who sell modern swaging machinery are the experts to teach the art; and it is to their IX Dextal Prosthesis. 133 especial interest that their patrons make a suc- cess of the work. CAST ALUMINUM PLATES. Cast aluminum plates are becoming quite a fad. Like in all other prosthetic matters, it takes practice to make perfect in tliis. I have seen enough of it to know it can be done per- fectly; and yet comparatively few, as yet, have the art perfectly at hand (1910). Even experts seem to disagree as to whether or not a cast aluminum plate is as impervious to the secretions of the mouth as a rolled and swaged one is. Again, others of equal experi- ence claim the metal itself is not fit for uni- versal use. And that 's my conclusion from what I 've observed of it. Anyhow, it 's gen- erally too light for lower ])lates, where weight is needed. If cast plates ever become common, then the Greene method of taking finished test im- pressions will be prized the more, because it eliminates all filing of plates after they are made, unless the mouth clianges. It will then be the more appreciated, also, ])ecause plates will be cast to accommodate the features, as well as to fit the mouth. With, oiu" plumperstest, the aluminum mold- er will not have to wax up a guesssplumper and then, maybe, file most or all of it off of his plate in red*hot stove-pipe verbosity. REFITTING LOWER CAST METAL PLATES WITH VULVANITE. Lower cast metal plates can be either re- fitted, or wholly renewed, with vulcanite. When refitted, tlie procediu-e is the same as we liave just gone through in refitting rubber plates, only 134 Greexe Brothers' Clinical Course the old metal plate must be scarified and pre- pared to hold the vulcanite lining mechanicalli). Of course you are all familiar with that matter. SUBSTITUTION OF WATT'S METAL PLATES IN PLACE OF VULCANITE ONES. To replace a \Vatt's metal lower plate in- stead of a vulcanite one, we take a modeling' compound impression in the old vulcanite plate, according to instruction for refitting; and test it to know for certain the plate, when done, will both fit and occlude properly. But, if you prefer a plaster impression, take it bv the "pass^word method," so you can act- ually test it. (Index P.) \Vhen your impression stands the test and the teeth occlude as they should, then invest j'^our case just as we did in the vulcanite refit case; only use a Watt's metal flask and some suitable investment material, instead of plaster. An equal mixture of plaster and powdered pum- ice-stone is good enough, especially if ground together dry in a mortar before mixing. Open the flask so as not to break the model, which, of course, is of the investment material and not very strong. When open, heat the plate-holding half of the flask hot and remove the whole thing — teeth, plate, and all. Then remove the teeth from the rubber plate and cement them back into their places in the in- vestment. Close your flask, blow in, and test for clear vents, dry thoroughly, cover flask' joint with silex and investment stuff, heat flask hot, tap and pour metal in slowly. This is a very simple thing to do, after you know how to take a test impression in an old IN Dextal Prosthesis, 135 (lenturL'. And, when it 's done, you "ve sub- stituted a new cast=metal plate instead of the okl vulcanite one, in less tlian two hours from start to completion. Of course you understand this includes both a re=adjustment of the teeth and correction of (K'clusion, if needed. TO REFIT AND RENEW A CAST PLATE WITH THE SAME MATERIAL. This process is just the same as any other refit up to the time of flasking. You now under- stand that. Xow use any flask made for casting lower {)lates of heavy metal, and flask as usual in that sort of work; using, of course, some pro]3er investment material in flasking, instead of plas- ter — something that won't crack and change by lieat. The pumice * stone - plaster mixture will do. Open and remove everything clean that con- stitutes your impression; close the flask, after coating the investment (not the teeth) witli h(|ui(l silex; tlien blow in to clear your vents. Then silex the crack l)etween the two halves of tlie flask to prevent the escape of the melted plate^material. Then dry well and heat it hot enough to melt the old j^late inside; and, while thus hot. ])our in the molten metal needed to make up for the space occupied by the impression. Cool it and take it out, and you '11 have both a refit and a new metal ])late. out and out. 136 Greexe Brothers' Clinical Course LECTURE NUMBER THREE. ARTICULATION, OCCLUSION, BITE, AND ALL THEY INCLUDE, FROM A PRACTICAL STANDPOINT. Well, doctors, in our "Third Degree' les- son we 're "up against" some of the most tick- lish matters that come within the whole range of our practice. First: the bite; and then all that follows till we finally dismiss our patient. In the word finaUii, I hope you fully catch my meaning. It sometimes means away off, and always an hour of rejoicing. In dealing with the subject of "articula- tion," as the word is broadly used, I shall try not to go into any mystical wording nor theoret- ical discussion. I '11 take for granted j^ou 've already had satisfaction and, probably, a surfeit of all that — and often to the exclusion of really practical information on the theme. You 've had actual measurements of dead men's jaws, and approximate and "average" theoretical measurements of living men's jaws. You 've had maxillary gymnastics and con- tortive movements on remote, if not imaginary, "planes" and hypothetical cinwes offered, and sometimes given you, till you maybe feel some- what as the old farmer, JNIoses Gouge, recently did at a toney town "kay*fay." (This story is vouched for h\ a reliable dentist, who insists on my using it as a happy illustration in this lecture. ) IX Dextal Prosthesis. 137 Waiter (politely) : "Beef steak, pork steak, chicken giblets, Belgian hare, quail-on=toast, baked fish, fried chicken, codfish*balls, turkey* breast, mutton^leg, ham, mackerel, or comitry* made sausage?" Plain Old Commoner (impatiently) : "Ohj you make me tired! Jist go 'n' git me the com- mon, home=niade sassage that 1 can kind o' chaw with this gol'blasted, jimble^tumble set o' teeth! They don't strike togetheh, so 1 can't eat nothin' much, neithah hahd nah saft" A new, enthusisatic disciple of "anatom- ical occlusion," across the table, butted in and gave the old Hay-seed a regulation dissertation on articulation of artificial teeth, in "meter" terms, on "occlusal planes," "condyle paths," and "face=bow" measurements, till he got tired again: "Yomig man, young man, if my teeth lacked o' cummin' togetheh right M-hen I chawed by your way o' fixing' 'em, accordin' as they do by the tutheh tooth dentist's larnt gibberish, I guess I couldn't hold 'em in, even when I steadied 'em with a big chaw o' saft terbacker on botli sides. If I could only jist git a set that 'd come togetheh rif^lit even one way, I 'd be glad to hold 'em that way, and let the tuth- eh fellehs have thairn to move in them uncom- mon ways, which you tell me mine had ort teh move an' come togetheh in. "In fact, strangeh, to be honest; while I wouldn't dis])ute yoh high college lahnin', T can't jist see lioxi: yo' 're gwoine teh make a set o' teeth that 'd awlis come togetheh right and even all 'round, when a felleh bit in dif- ferent ways. I know that even my old ter- backeh'Wohn=off ones didn't do that. 138 Greene Brothers' Clinical Course "You might do it in yoh' 'unknown tongue,' hut, as the felleh says, 'I 'm from Missouray.' "1 reckon, of kose, if the okl Masteh had tuken sich a notion in Plis head, lie could o' made all teeth hit togetheh all 'round, no mat- teh what direction nor tchat we l)it on 'em. But one thing is shoh: He didn't make in'iuc, noh none of my five wives', noh seventeen chillern's do it. "Well, 1 may say, 'cepflu' in one case; that o' my fo'th wife, Suz=an ^Nloriah. An' she it was who made hern that=a=way lieh own self. She was allez stickin' her cliin out an' grittin' her bulldog teeth at me an' my chillern by my tutlieh women. She woh' her front teeth off so loAv an' even that ,s7/^' could bite on 'em any ways, I guess. "But, now, I wouldn't want my neighbohs to think / had my shop^made teeth patterned afteh ^loriah's, nohow-." Well, doctors, we'll first set up a double set of teeth that will come together exactly right "one way," the most natural way. Then we '11 set them to strike like Suz=an ^loriah's, "any ways"; at least, any practiced way. And we '11 do it without any circumlocution- ary verbal mystification, or "unknown tongue," to describe it; or even complicated, ponderous articulating machinery, that requires an anat- omical engineer to run it. We'll try to make it all so simple that even a wayfaring (etc.) dentist can understand. ^ly piu'pose is to show you how to take a test articulation (so-called "bite") and prove its correctness in advance, tlie same as we test- ed our impressions; and how to set up teeth in even the common, old plain line articulatoi', and get all tlie movements the jaw makes in pr(ictic(d use — and even more, too, if you want IN Dental Prosthesis. 139 them. Yes, and as for that, aceoinplish the same results, even without anii articulator at all, other than the mouth itself, as for that. One of the hest plate^workers I have ever kno\\ii, working hy the old guess=work methods, has made artificial dentures for fiftyseight years, and has never had an articulator in his office. And though 1 have used articulators my- self for fifty-two years, I will here say that if I had no advance test methods in getting the true relations of tJie jazcs (the "hite"), hut had to guess*off everything, as I used to do, and as most other dentists still do, I would note throw my artificial articulators, "anatomicals" and all, onto the junk^pile. For, without this true relation, the hest of them are not only faulty, hut may he ahsolutely misleading. But, with the eertainty of the true relation of the jaws when at rest, and a close approdiina- fiou to their movement in action (the "average"), and with an articulator to help manifest these relations, we get a very close approximation to a correct articulation and occlusion. There is no trouhle in getting the exact, true i-elation of tlie jaws at rest in any individual case. But as to their relation when in motion we must he content, at the first, to get even a close approximation. We have heen given the true measurements of dead men's jaws and ingenious face ' how measurements of living men's jaws, "occlusion planes," and "condyle ])aths," and the like, eveJi unto hypertechnics. And thanks, honor, and glory to the men who have given them. Their teaching is often hel])ful, at least instructive. But, unfortunately, when most needed, the starting points can't he located with certainty 140 Greexe Brothers' Clinical Course (excepting by the imagination of enthusiasts) and the measurement is only approximate, af- ter all. Xot all jaws move alike, nor does the same jaw move always on both sides alike, nor does the same jaw at all times move the same. So we sometimes have to work to greatly varj^ing bone anatomy, of impossible actual measurement, and to irregular muscular move- ments, that just can't be relied on at all, ex- cepting as a plausible theory. But nevertheless we can deal with each in- dividual case on its own merits; and get prac- tical results, no matter about the size or shape or angle of the jaw-bone. As a whole, shortly told, we '11 do as we did in our impression. We '11 get first an approximation and then cor- rect up to exactness in these matters of articu- lation and occlusion. So now, as to the not only varying, but even changing muscle movements that we must deal with. In articulation we sometimes can't depend on adjusting our tco/A" to the movements of the muscles that operate the jaw. We rather must depend on adjusting the movements to our work I am aware how absurd it may seem to some, at first, to propose to adjust the jaw movement to a set of teeth; and yet, if it were not possible and expedient, the most grateful science of orthodontia would be fatally crippled. The orthodontist must sometimes adjust the maxillary connections and accommodate their action to the position he has given the natural teeth. He couldn't have gotten his grateful results without having trained the movements of the muscles (that moved the jaw) to his work; that is, to his changed position of the natural teeth. IX Dextal Prosthesis. 141 NOW FOR THE " BITE." The too common idea of a bite is: the nat- ural, horizontal relation of the alveolar ridges of the upper and lower jaws. It is, however, correct as far as it goes; but it doesn't go far enough. To this limited idea should be added: tcken they are at proper distance apart, perpendicjilarhj. Even the horizontal relation of the jaws often changes as the distance apart varies. Then, a practical definition of a sO'Called "bite" would be: The natnral, horizontal re- lation of the jaii'S ichen at their proper distance apart. The distance apart meaning the length of the teeth to be, plus the combined thickness of the bite^plates used. But strange how man\^ dentists, including some of the brightest among them, fail to con- sider the distance apart of the jaws in taking a bite. Indeed, I 've found more than a few who contended even that the distance, or width of the bite, makes no difference; hence they could change it at will after taken. For example: If you need a starter for thinking on this feature of our theme, just open your oicn mouths and observe how much faster the s])ace increases between your front teeth tlian between your back ones. AVhat 's true of your natural teeth would hold just the same with your gums, without your teeth ; or with plates of artificial teeth. Xo correct bite (or horizontal relation of the jaws) at any given distance apart would be cor- rect at any other distance apart. Then the first thing, and tJie thing, in tak- ing a bite is to settle on the distance apart you want the jaws; or, in other words, the 142 Greene Brothers' Clinical Course combined length of your teeth, inckiding thick- ness of their phites. And now this must be exact, too. Xor can it be changed after settled*on and in the articulator, unless your articulator pro- vides for the opening, or dosing, at the heel the same as in front. Xor is any change of this sort (widening or narrowing of bite) ever necessary, if you will ascertain to a certainty, before you take your bite, how long you want your artificial teeth, including plate, to be. That is, in effect, how nuich you want your teeth to shoic. We '11 call it tlieir show*length. And this is easily de- termined and settled with certainty, as you will presently be shown. ABSURDITY OF A COMMON, MOTIONARY BITE. In all dental prosthesis, and indeed in all dentistry, and in all the unphilosophical ideas and acceptations therein, there is no greater uncertainty than that of a conunon, inotionary (pardon the doubtful but needed new word) bite; no matter in what "way" nor how you may take it. In fact, when closely scrutinized, it amounts to practically an absu relit y, even though you do sometimes get the correct relation of the jaws by it. In certain kinds of difficult cases, to be mentioned later on, success would have to be almost an accident. Absurd ioY this reason: You ask your pa- tient to give you her "natural" bite, when she really has no regular bite to give. She used to have a regular, or habitual bite when she had her natural teeth. The teeth then held her jaw in a certain 2)osition so much IX Dental Prosthesis. 143 of the time that it, in fact, regulated and es- tahHshed the movement. And that movement then was her "natural" hite. She tJicti liad no troul)le at all in opening and closing her mouth very nearly the same way every time; the same as when hahit reg- ulates the muscles that give the drilled soldier the same "regulation step" every time, if there 's nothing to interfere. You and I who have teeth, either natural or long=worn artificial, have our hahitual ( "nat- ural") bites. But pull our teeth out and let our jaws hang loose awhile, like a bell=clapper, or clockspendulum, then our muscles that move our jaws relax and lose their habitual action. Then we have no natural bite to give. We have simply lost our habitual bite. .Vnd fJicii to cram a mouth full of unnatural filling and under such circumstances to expect a natural, same bite is the acme of presump- tion, if not an a})surdity. So, we 'd just l)etter take for granted that our patient, having no longer a certain habitual action of her jaw, can't control her movement: tlie morcnu'tit, mhid you. That is, she can't bite for us reliahlf/. TIRED RELAXATION THE NATURAL POSITION OF THE JAW. But, though slie has no longer an estab- lislied, habitual movement of her jaw, she al- ways has a natural rest position of it. We '11 call it a tired-rest position. For instance (to my clinic=student at my left) : ^ladam, let us illustrate our case. Open your mouth and stick your jaw out at me for a little while. Don't let your teeth come quite 1-44 Greexe Brothers' Clinical Course together; but hold them just that way a few moments. Xow, how long could you hold it in that strained position, with nothing to rest on^ "Not long," you say. Xo, of course not; but what would happen when you couldn't hold it out any longer? "It would go back," you reply. Back, but where to? "Back to its natural place, of course," you answer. That 'a it! When your jaw is tired, it goes back to its natural-rest position. But it doesn't have to be stuck out that way to tire it, at all. We can tire it in a simpler way than that. I have used that way to impress you with the principle. We can tire your jaw quite sufficiently in a minute or less by merely holding your gums apart, with your lips Ji^hthi touching. We '11 apply the principle, in taking a bite, now soon. WHAT DO WE EXPECT FROM A BITE? There are four important points that we should secm'e in a bite. First: The length, or showing (showslength) of the teeth. Second: The out^standing, or in=standing, of them. Third: The come together, or occlusion, of them. Fourth, but not least: The strain, or press- ure, with which tliey come in contact. Though the fourth point is unthought of by ninety-five per cent of dentists, it is extremely important; since the Avhole matter of occlusion may largely depend on it. We will deal at- IX Dextal Prosthesis. 145 tentively with point four in its place a little later on. There are two methods of taking a bite, with variations in both. One is known gener- ally as THE "BISCUIT," OR "MUSH," OR "SQUASH," BITE. It consists in placing a roll, or chunk, of wax, or other material, in the mouth and having pa- tient simply "bite" on it. The other is known as THE RIM BITE. Basesplates are made of various materials to approximately lit the gums, and rims of wax, or other material, placed on them; then bit'On and marked, and fastened together on their models, in the articulator. These are the two methods, given without detail; and it is sup- posed that you are familiar with one or the other, or both of them. My only use for them is as a basis for illustration and improvement. By tliis biscuit bite, you get no otie of the four points needed, iWdCtJif; and seldom very approximately, unless sometimes when it is pro- vided to give the first one (length of teeth), in a way, by use of a "bite=stick."" This is accomj)lished by placing a piece of wood in the "biscuit" to stop the lower jaw at the ]u-o])er distance from the upper one, and so give the length of the teeth. But, as this is seldom done, it is safe to say that generally in the biscuit bite you get noth- ing you want, excepting a very remote approx- imation of the relation of tlie jaws. It is really about all guess-work. [10] 146 Greene Brothers' Clinical Course And whatever success is attained to, can be attributed to your experience and good guess- ing, in setting up the teeth and trying them in the mouth; the unrehabihty of which will be dealt with later on. By the way, before we close this demonstrat- tion, we '11 give you some important improve- ments on the old "mush" bite, that you can give your friends wlio persist in its use. For yourselves, you '11 have no further use for the method, even improved. This rim = bite method ^vas originally in- tended to give the first three of the aforemen- tioned points; that is, length, prominence, and occlusion. But, as tlie method has been seldom prop- erly taught and practiced; and as faulty ma- terials have been used; and as dentists, dis- couraged, have adopted and rely on the "try* insthe=mouth" plan; and as the rim bite (as it is commonly used) has to be followed up by cut=and=try guess-work to get even what is at- tainable by it, I '11 give you. THE GREENE IMPROVED AND PERFECTED RIM BITE. This gives all the foil?' requisite points with- out any guess-work. And this is the work we are now up to. BITE FOR A FULL UPPER=AND=LOWER SET. We have our models, over which we are go- ing to vulcanize, or swage, our plates. If we take good impressions of them in "Perfection" Im- pression Compoimd material, our impression- bitesplates will fit to the gums about as well as the finished plates made from them will fit later on. And a good=fitting bite=plate, one that IN Dental Prosthesis. 147 will stay to place, is an essential in the bite. Don't lose thought of this. UPPER MODEL FIRST. We '11 take our upper model first; lay it down on the table, face upward, soapstone it well, and carefully take a "Perfection" mate- rial impression from it. This impression, taken without a tray, will liave a rim of ample thickness and prominence, for trimming down to what we may want. But its palatal arch Avill be pressed down thin — say, doAMi to an eighth of an inch in thickness — to avoid bulk; and made smooth. It will then constitute our bite^plate, in the rough. In a few cases, where a model will have a projection, you will, before taking an impres- sion of it, have to core out the "under'Cut" with a little compound, and cover this with thin foil, so as to get it off the impression without damage or trouble. TRIM FOR FULLNESS OF UPPER LIP AND TEETH. We '11 now put it into our patient's mouth, after a little explanation to her, and say: "Now, JNIadam, suck that up tightly." To begin with, it purposely makes her lip a little too prominent. But ^^e trim off until it suits us as to fullness of expression — without regard to the lower jaw, at all. In fact, we hold our hand over the lower lip, during the adjustment of the upper one. to avoid being misguided by the contrast. The trimming is done similarly to that in side*trimming an impression: first warming the outer surface to a very slight depth over a hand'lamp, and then using a sharp pocket=knife. 148 Greene Brothers' Clinical Course It now reprensents the fullness of our coming denture all around. AVhile I 'ni not here to teach you physiog- nomatic taste, at all, I will suggest that you don 't give your patients a cat^fishy appearance by too square a front and too prominent bicus- pids — ^^a very common, distortive habit among dentists. And always beware of tucking the front teeth inxcard, or the bicuspids oiitncard^ too much; especially for a woman — unless you want to make her husl)and, or beaux, look at some other face. All dentists guilty of this unpardonable sin against featural symmetry should be de*licensed. And oh, what a lot of vacant chairs there would be! TRIM BITE=PLATE FOR LENGTH OF UPPER TEETH. Next we '11 get tlie "lip=line" for the show* length of our artificial teeth. This you can get in your usual way, whatever that is; only be sure you get it. I prefer to use the laugh* stunt, as a rule. We look her in the eyes blandly and say: "]Madam. please smile or lan^h a little at me, will youT' She laughs, always promptly, when told to. So we trim till we get the rim to ve\i- resent the exact length we want the teeth to show; that is, their show=length as far back as they will show. Then, not as a matter of taste, but as one of mechanical philosophy, trim off the rest of the rim behind so as curve gradually upward; and make your last molar as short as possible (the exception would be M'here you want to prevent the cheek from falling inward) ; first, that your denture may have the "compensat- ing curA^e" (incidentally) ; but for another more IN Dental Prosthesis. 149 potent reason than the one usually given, to be explained later on. So now we have our upper rimsbitesplate to represent our teeth when set up. It will be our guide, too, in setting them up. Xext we '11 do the same thing in our lower case. As in the upper, we '11 get, again, our rim*plate impression from our lower model (or from the mouth, as for that) . But we must see that it will stay dozen — ^^somewhat, at least — to its place in the mouth. This is important and almost essential in getting an ante^test bite. If tlie mouth has an alveolar ridge, it will suck down; but, if not, we must other- wise provide for its down^stay. In this flat, flabby case, we must have a substitute for suction in our lower bitc'plate. HEAVY LOWER BITE=PLATES. Here icatch mij most valuable little invention ever made in bite-taking-. We '11 take the im- pression of our lower model with heavily tceight- cd molding compound — that is, compound with fine bird=shot well kneaded into and through it; and even with small bars and rolls of lead also worked into the rim, if necessary, to hold it down to place. TRIM LOWER BITE^RIM FOR LENGTH OF LOWER TEETH. AVe 're now ready for trimming and fitting our lower bite-plate to the up])er one. But we '11 reverse the order and get tlie sliow=lengi:h for the teeth first. Don't forget that in the up- per case we first got the fullness and then the show=length; but in the lower case it is exactly reversed. And now, doctors, here is the tvay we get the lower bite^rim to the showslength of the 150 Greene Brothers' Clinical Course lower teeth; and also get it to fit to the upper rim. For they must fit to eacli other perfectly; their edges occlusively and outer sides evenly, laterally. With the upjDer bite-plate left out, we place the lower one in the mouth and mark the lip* line, and trim to it in front — 'say, to about the combined width^space of the incisors. In scru- tinizing for the length of the teeth, look at this trimmed place only, for it is the stop-guide to the rest of the trimming, to be made elsewhere. When this guide^point is down to the show- length that we want the teeth to be, we soapstone or tin- foil this trimmed spot. Then insert the upper plate, with its full occluding edge like- wise soaped, or foiled, and cool. Then warm the occluding edge, only, of the lower plate, and have patient to bite down quickly. (This isn't taking the bite, excepting the press^strain feature of it.) The trimmed guide' point is cool and hard and inmmned from sticking, while the rest of the rim is soft on top, so it will mash down in forced contact with the hard upper rim. In an instant she has mash ' trinmied her lower bite^plate to exactly fit her upper one. Xow when we trim off the mashed^down surplus, our whole lower bite-plate rim repre- sents the coming lower denture as to its show* length, or, rather, height; but only as to that. It "compensatingscurves"' upward at the heels, too. Well, provided we M'ant such a curve. THE OUTSTANDING OF THE LOWER TEETH is our next point to make. We must now trim the outer side of tliis lower rim off all around even with the upper one. And the two rims must be even Avith each IX Dextal Prosthesis. 151 other icJicn thcij arc in their exactly true natural relation to each other. That is to say, when we have the correct so==called ''bite." When we determined the show=length of our teeth, at the laugh'line, or elsewhere, we set- tled, by critical observation, the perpendicular relation of the two jaws; now we must settle their horizontal relationship. This can be done with certainty, only when the lower jaw is at tired relaxation, which is normal rest. And, doctors, whether deserving or not, I Avill here venture to throAv a little boquet at my own old feet. Whether the discovery is orig- inal or not, I am sure I have never known it mentioned, in all the forty years of my prac- tice and association with dentists, before I be- gan to teach it in my private Course a few years ago. I mean the taking of an immotionary. still bite; or no'hite, as I will now call it to the end of these demonstrative talks. But even though the idea were not original, to be the unquestioned introducer of it ])racti- cally to the ])rofession is sufficient honor. THE TIRED=REST TEST=BITE, OR "NO=BlTE." We will now take it, then trim the lotver })latesrim off to evenly match the upper one. I could describe the ])rocess more briefly, but less impressively: so I'll use our dummy l)atient in the demonstration: "JNIadam, you now have the two ])lates in your mouth. They will stay to their ])laces. If necessary we '11 stick them onto the gums Avith paste or gum-tragacanth. Look me in the face, listen to what I say, get my idea clearly, and do promptly what I tell you. ( /.//(. 152 Greene Brothers' Clinical Course "Close your mouth till your lips come to- gether lightly; but let the plates remain just a little bit apart, but so thcij 'II almost touch." The plates ai;e within about an eighth of an inch of each other, and too near to admit of uninicndcd lateral motion in closing this last minimum space under the directions. "There, there, you have it right! Watch, listen, hold just that way till I slowly count ten. Then bite down somewhat firmly, and hold down, no matter what I may do with your lips. Watch: One, two, three, four, five, six, seven, eight, nine, ten — snap! Hold firmly." The upper rim sits down on the lower one at tired ' rest position — provided neither plate moved. And here you see the utmost import- ance and necessity of well ' fitting, bite=plates. If one or the other, or both, had slipped, ever so little, the result would have been equivalent to that of a really wrong bite, to that extent, by side movement of the jaw itself. And how many bad bites of this sort have we all had from bad= fitting and sliding bite*plates? How many hun- dred have you had ? Are you all impressed? If so, we will re- turn to our patient. "Hold still, Madam, while I mark the lower IDlate." I here take a small instrument with a right- angle turn near its point and scratch all around on top of the extending lower rim, against the trimmed upper one. That is to say, my upper rim guides my marker. Then, to rest my pa- tient, I take both plates out and trim the lower one off to the scribe carefully. This brings them both even; and even, too, xichen the jaws are in their natural relation — provided I can IX Dental Prosthesis. 153 "show" it (and I ^^roudly hail from the "Show= me" State) . Well, I have now attained the third one of my four essential points in a bite: (1) show* length of the teeth; (2) the come*together ; and (3) tlie Up and face features. The teeth will / relate just as these bite=rims do. / RE=INSPECT NO=BITE FOR FEATURE TEST. But, to make sure the face features will suit ?ne, and thus help me to "suggest" my patient, I '11 replace the whole thing in the mouth and re^inspect. After all this, however, you '11 not need to make, on an average, one change in twenty- five. But should you see fit to do so, all that you need to do is to re-trim your rims in the same way you did in the first place, but more carefully. You can place your bite=plates on their mod- els, warm the rims, and push them outward or Fig. 16. Fig. 16. — Greene Tired-Re-.t Test-Bite (no-l)ite), with molding- compound im])res.sion.s, as bite-plates — (in this case handleless trays). The models are made wlien case is articulated. 154 Greene Brothers' Clinical Course inward. You can trace compound (at least, this "Perfection" brand) on, or add it in strips, for more extension; or trim it oif for reduction. FOURTH POINT, OR PRESSURE FEATURE, IN A BITE. Xext and last comes the fourth point of essentiahty in a bite. This is the pressure, or strain, with which it must be taken. (And here I '11 take the risk of justification in another bouquet at my own feet.) In traveling seventy-five thousand miles, in fourteen years, among dentists, I have found less than a score who had ever thought (out loud, at least) of the importance of the strain with which a bite is taken; or even of a set of teeth set up together. And only one of these had at- tempted to regulate the matter in his work. I fraternally wish I could recall his name; he was in my first class in Washington, D. C, in January, 190? He had invented an inge- nius little instrument to measure and regulate dentalsplate pressure; only he hadn't had time to perfect his appliance to his own satisfaction. His purpose, of course, was to apply it in a bite. A SIMPLE, PRACTICAL PRESSOMETER. We have been over and over the importance of taking impressions at about the stress a plate is to be Morn — as a rule with few exceptions. And this stress would be at about strong suction strain. Well, it 's just about as important that a bite should be so taken, too. Otherwise, our occlusion wouldn't be as expected, and we 'd have more or less after=grinding to do. or else waiting to do till the tissues absorbed and ad- justed themselves to the plates. Many a bad IN Dental Prosthesis. 155 occlusion is the direct result of improper press- ure in bitc'taking. It is astonishing how many of us, includ- ing scores of our deep "anatomical" thinkers, have so long danced blindly all around this now plainly visible goddess in the popular Oc- clusion Show. But we have all heard of the j^oor, tired prospector who sat down on a boulder of gold, at Cripple Creek, Colo., to unwittingly rest on a fortune, after he 'd worn himself out at dig- ging and searching for it with a microscope, in doubt, away do^^n in the unknown depths of the mountain. If I hadn't such well'grounded prejudice against commonly sl&ndered names, I 'd call my instrument "Eureka." But I '11 wait til] some other fellow "invents" the same thing and let hijii so name it. I '11 christen it: Pressometer. To describe it and show its workings, we '11 go back to our finished no^bite. It looks like it is finished, for the plates seem to come to- gether all around alike. In fact, in a way they do so. But we don't know yet how much more strain ■ — excessive strain — is being made some place, or ])laces, than at others to make them do so. If it takes too much strain, the teeth wouldn't come togetlier perfectly at the natural strain at which they will be worn. And of course other difficulties come "in flocks and droves" in con- sequence of improper occlusion. HOW TO USE THE GREENE PRESSOMETER IN A STRAIN TEST. As a test of stress, we '11 use these two nar- row, thin strips of celluloid, or its equivalent, about half an inch wide, one*thirtieth of an 156 Greene Brothers' Clinical Course inch thick, and four inches long. They are as smooth and shck as a glass mirror. They are beveled at one end, so I can lay one on each side of my lower bit*rim (in the mouth) and have them come jointly together in front, form- ing a letter V. They are also rounded off on the outer side at the heels, so as not to be caught by the cheek. And, when laid to place for use on the lower bite*rim, they also project out in front beyond the bite*rims, so I can handle them with thumb and finger. The two together con- stitute the full pressometcr. In a simple case like this, I place the two halves, one on each side, on my lower bite- rim, with the letter V pointing toward me. "Now, Madam, bite down on these strips." She bites, and they both are held fast; but this proves nothing; for I don't know how un- duly hard she is biting down, nor how much some parts of her gums are giving way more than other parts, to make them thus tightly hold. Then I say: "Hold, ^Madam, hold! Bite lightly/' She bites lightly, when one of my test pieces holds tightly, while the other slips loosely be- tween the bitesplates. This shows there was more strain on the tight side than on the other one, for the slips are of the same thickness. I now take the lower plate out and file it off (it is here modeling compomid) with a coarse vulcanite file, and try it back. Now when she bites lightly, they both hold alike and slij) alike, loosely, showing the pressure is the same; j)i'e- cisely the same. Then teeth, set up by these equalized bite*rims, will be of a likeness in pressure. IN Dental Prosthesis. 157 If I hadn't filed off the hite=rim, but had gone on and set up the teeth by it, I would have had to grind ihcm off equivalently. UNEQUAL PRESSURE SOMETIMES NEEDED IN A BITE. But, now, I wouldn't have you understand me that stress should alrccu/s be the same all over tlie mouth. That is the first conclusion new thinkers are apt to jump to. But in many instances the strain on the tissues should l)e unequal at different places. For instance, we have a mouth where the gums are soft and yielding on one side, and hard and unyielding on the other side. In the absorbing adjustment which always takes place, more or less, under artificial dentures, especially lower ones, after worn, the softer side will change more than the harder; and then finally the teeth would strike together first on the harder side. In this case, the test=slip, in testing the bite, should hold the tighter on the soft side, where the most absorption is to take place. We have pairs of these test^slips of unequal thickness for sucli cases. Similarly, if we had a case where the mouth was soft at the rear and hard in front, as is often the case, then our slides should hold tight- er back tliere than on the alveolar ridge, in front; and vice versa. So, you see, the principle holds good both ways. So the simple i)ressometer not only en- ables us to get equal pressure wlien we want it, but often, as importantly, to get unequal strain when we need it. This rule, however, is not alicat/s ])ractical, as in temporary cases, where the alveolar proc- 158 Greene Brothers' Clinical Course ess is to become much absorbed. Nor is it ap- plicable wlien small, soft spots are supported by hard ones near by. Xevertheless its need is so frequent and use so grateful that it might be called golden. VERIFYING THE NO=BITE. We have taken our still'bite and secured the points essential to setting the teeth up as we want them; or with close approximation to it. That is, we guess we have so taken it. Let us now eliminate the guess*factor from it. To be certain of results, we must verify this no'bite before we put it in the articulator; for it is within the range of possibility that even in our tired=rest short bite one or the other or both of our bite=plates may have slipped on the gums. It isn't probable, but possible. Also it is possible tliat the lower jaw may have moved a little bit laterally; Avhich would give us the same bad occlusive results. Let us, then, even mathematicize our proof*test. We have made one no^bite at jaw^tire num- ber ten. That was when we scribed-marked our lower bite'rim, to trim it off even with the upper one. Xow if we can have two or three more of the same time-length, and they all register alike, we can know with about mathematical certain- ty that we have the natural position and rela- tion of the jaws at rest. MATHEMATICAL TEST OF THE NO=BITE. To make it, Ave '11 cut, say, three test V' shaped notches in our upper bite-rim; one right in the front-center, and the other two — one on each side — about the place of the first molar. Then give the command: IX Dextal Prosthesis. 159 "Xow, Madam, I want you to give me an- other slow, shortsbite, just the same as you did before. Close slowly till your lips touch lightly, and hold the plates as closely together as you can tcithout toucliing. You now know how to act promptly. ''One, tico, three, four, free, sid\ seven, eight, nine, ten — snap! Hold now, as before, till I mark again." I this time make a perpendicular mark on the lower rim immediately opposite the very center of each of my test^notches. Then I take the plates out of the mouth and with the Kerr tracing^stick I hot=drop three small test=knuckles onto the lower bite-rim to fit into the test notches above. (Here this lit- tle fine art is shown i)ractically; by first droj)- ping a molten wee-bit of the roll tracing^stick onto tlie occluding edge of the lower rim. right op]>osite the mark thereon, and pressing it. a little bit, into its mate^notch on the upper rim, thus forming a test=knuckle. ) We make the first pair of notch=and=knuckles centrally in front; then one on either side, one at a time. To ])revent sticking together, one or the other of the plate=rims is dipped into cool water the instant before the two are pressed together (outside the mouth.) We then trim off any little side surplus about the knuckles, and re=warm and press back together, to make sure these latter knuckles don't interfere with the exact coming together of the rims hettceen them, whicli miglit destroy our proper stress, established by our pressometer. This fitting the knuckles into their notches recjuires care, but is (juickly done — yes, in one minute of time. 160 Greene Brothers' Clinical Course THE THIRD STILL=JAW TEST. That is ticicc now, we \e tired the jaAV at number ten; let us have another tired bite of the same duration; this time to see whether or not the test=knuckles will jibe properly to- gether into their match=notches in the mouthy just as they did out of it. "Again, Madam: One, two, three, four, five, sia\ seven, eight, nine, ten — bite!" If the knuckles register into their mate- notches properly, as they will if all has been done carefully, we have thus taken three no* bites at three different times, and all just alike; and no error or doubt about it. We could take more, if necessary, to please a surprised Thom- as — and sometimes do so. Once I had a "Smart Alec" insist that I couldn't convince hi?n of the correctness of cuu/ bite, or "no*bite," no matter what "proof" I Fig. IT. Fig. 17 Shows testometers in position between impression- bite-plates. The pressure test is made with the "no-bite" in the mouth, of course. IN Dental Prosthesis. 161 might show; as he had been "fooled in bites too often." "Well," said I, "for your sake I '11 admit this to be wrong; not uncertain, but tcrong. AVould you be satisfied if I could set up a set of teeth just tliat wrong, with their cusps and counter^sjjaces knuckling together like these, in the mouth?" "Yes, I tJteti would be satisfied," said he. So I proceeded to sliow him by setting up the teeth. And that is wliat I will now do for you. TRANSFER NO.BITE TO ARTICULATOR. We must now transfer the no-bite from the mouth to the articulator, which is to be an approx- imate representative of the i^eal anatomical, bone* and-flesh machine itself. But now, before I leave the no=bite, I must say, of course, in the remote event that our notches and knuckles sliould fail to jibe togeth- er in the last tired=short=snap'test, it tcould be because one or more of the times the bite'plates (one or the other, or both) did slip; or else be- cause the lower jaw really did move, in some degree, horizontally. It couldn't be otherwise. Then I 'd do the notchsandsknuckle ^vork over till I got my no=bite test. ANATOMICAL MOVEMENT ON THE NO=BITE. If I have what I call a "crip])le" case, I make that individual mouth its oavu articulator, in a ]jractical sense. By a "cripple" case I mean, for instance : (a) A prominent "jimble^jaw" of extended mal=])rotrusion; or, (h) One of the reverse, retrusion : or, III] 1G2 Greene Brothers' Clixical Course (c) One where one wing" of the maxillary is much longer than the other ; or, (d) One where there is evident erratic move- ment on the "condyle path," on one or both sides of the face; or, (e) One where the hide*andsgo*seek condyle socket, needed for the face=bow measurement, is so covered with tissue that it can't be located reliably, as a starting=point; or, (f) One where other mal* formation or mal= action is in obvious evidence. I say: In such cases I make each individual mouth naturally its otvn articulator, either wholly or in a very close degree; using artificial ma- chinery as a convenient, approximate assistant. A "CRIPPLE" MOUTH ITS OWN ARTICULATOR, IN THE FINIS. To do this (/. c, to make a reed automat- ; ic articulation ) , I take my completed no - bite (sometimes un=press=measured) and trim about one*eighth of an inch off the top of the lower bite^rim; say, from the second bicuspid rear- ward. Then, in the place of this removed ma- terial, I fill=on a facing mixture of plaster and I puhxrized pumice-stone (plaster one to pumice j three), with a little extra fullness on top. Fine molding-sand with plaster is good. This soft^stone, as I will name it, is frail enough to be readily worn off by attrition. The upper bite^plate stays to its place, and (by my several improvements) likewise the low- er one, too. Of course, these stationary con- ditions are essential to the operation. ISTow, with the upper bite'rim cold and rigid, I have patient chew=grind the two bite=rims together (the upper one being hard modeling I IX Dental Prosthesis. 163 compound) with the natural movement of her jaw, until the soft^stone facing is worn down as much as the compound in front of it will permit; that is, to genuine anatomical occlusal representation. (Some of my enthusiastic anatomical friends may rc'invent this little, but exceedingly valu- able, Greene^point, and name it their "Anatom- ical Grind'Stone ^Method." if they want to.) Occasionally this anatomical abrasion of the soft*stone may be so much as to hinder the l^lacing of the no^bite in the articulator ^^ith convenience and certainty. In such a case, I stick a thin sheet of tin^foil on the abraded soft=stone, and put a little thin-like plaster on the foil ; and then have patient no=bite lightly straight down on the plaster — this time without lateral motion. This restores the lower bitesrim and enables correct arrangement in the articulator. I could use modeling compound instead of l)laster for this restoration of my abraded soft* stone, but it might get too hard and give un- due pressure, and thus spoil the accurate effect of the occlusal abrasion. ^Medium soft plaster is about right. Understand: the only use for the soft plas- ter restoration is for convenience and safety in transferring the no^bite onto the articulator. When setting u}) the teeth (the upper) by the guidance of the lower bitc'rim, of course the plaster level*up is first removed, then the teeth occluded to the worn abraded soft=stone. We '11 carry out the rest of our anatomical, occlusal, guide'bite'abrasion scheme to the ulti- mate anatomical occlusion of the two sets of teeth a few minutes later on. So far we 've only been getting ready to use our artificial articulator first; before apply- 164 Greene Brothers' Clinical Course ing the newly discovered last act of making a cripple mouth its oicu articulator. (A class=man asks: "Why isn't this a good way to take anj^ other than a "cripple" case biter' It is, but it 's not often necessary where our regular no=bite scheme can be accomplished^ but it's never amiss. ) Another question: "AVhy not use some sort of hard, thin wax base=plate and put modeling compound on it for a bite-rim T' That 's our old way. You can do it if yovi can get a well* fitting basesplate: essential in any bite method. As for that, you can do better by swaging a metallic bite==plate and using a modeling-com- pound bite-rim on it. You can tlien. when in the articulator, remove the compound rim and replace it witli sticky wax. on which to set up the teeth. Any bite=plate that will stat/ to place without assistance. But, if you make the "mouth its own ar- ticulator," the hitC'rim must be of material that will stand the natural, automatic grind=mashing maneuver; which is done first in the bite — later, on the set-up teeth themselves. CORRECT BITES TILL THEY DO TEST. If, in any case, our no=bite test should, from any cause, fail, then the remedy would, of course, be to do it over; or as much of it as necessary, until we get the absolutely "math- ematical" proof we need. But with care from the start you '11, indeed, seldom fail to make the jibe^test on the first trial. But right here let me, before I forget it, run l)ack and suggest tliat in case you shouldn't liave time to wait and make models, from which to take bite=plate's impression, you can take them directlv from the mouth. IX Dental Prosthesis. 165 That is, you can take one set of impres- sions for making vulcanizing models later on, by keeping them in cold storage till ready to make the models. And then you can take an- other set of impressions, and take the no^bites on them; and put them likewise in cold water till you get ready to make your models and articulate your case, weeks or months later on. Or, you can take your no=bite readily without waiting to make models, by using the impressions themselves as bitc'rims, with the Greene=Kerr Removable Handle Impression and Bite Trays — ^^as I '11 soon show you. FIRM ARTICULATOR IMPORTANT. As to articulators, I will say: Tliere are some good ones and more bad ones. My objection / is to those of needless complication and bulk, / and those that are flimsy and flexible; espe- cially the latter. I find articulators very much like inlay ma- chines; some are perplexingly ingenious and others ingeniously simple. And the funny thing about it is that the good plain and complex ones give about the same result, if properly operated, from a tested no=])ite. Anyhow I can get all tlie real advantages in a simple, light but strong, plain, old=style articulator, by a little im])rovement, tliat I can make in a few minutes. The only exception is that I can't open or close (widen or contract) my bite after in the articulator. But by my advance^test system I never need nor want to do that. With it I can make all the movements the jaw makes in actual use. It is the pattern I find in use {minus my improvement) in nine- 166 Greene Brothers' Clinical Course tenths of all the dental offices I visit; hence I use it mostly in my demonstration. But this is not condemning all others, at all. The essential of an articulator is that no ])SiYt of it can move, nor especiall}^ spring, with- out purpose effort. The old Bonwell is partic- ularly faulty in its flimsmess and consequent liability to change the bite; on account of which so many failures are made that the "springy old thing" has been generally discarded and junk=piled. And yet the faulty Bonwell is good enough in the hands of the few dentists who persistently self'train themselves in exceeding carefulness. To illustrate tliis important weak point, I carry with me an old plain=liner with its upper jaw so weak as to be sprung carelessly and thus change the set-up teeth from the accepted bite, and ruin the occlusion. As the spring,, by care- lessness, is usually toward, the result is to cause the teeth to strike together first at the heel, when inserted into the mouth. Well, as this fault applies to so many ar- ticulators, I will show you the consequences later on in this lecture. I will add here, however, that as I am not pecuniarily interested in articulators, and as life is now^ too short (at seventy-five) to enter the "anatomical" arena, I have not tried all of them. But among the simple modern ones I have used and seen used, with satisfaction, is the "Kerr," made by the Detroit Dental ^lanufacturing Company. The untried ones may be as good. ARTICULATOR IN MOST COMMON USE. I M'ill here make my demonstration on an improved old-fashioned plain*liner, because of IN Dental PRosTHEisis. 167 its simplicity with efficiency and because of its being most of all in general use among those who take ni}^ Course. In placing first my lower model on the lower jaw of my articulator, I want its alveolar face about on a horizontal plane with the metal jaw- under it. You can readily so trim, or thin them down so ^vith the use of calipers. And my ready* made metal models are generally already so trimmed. (They are manufactured by the Detroit Dental jNIanufacturing Company.) I can use a "face^bow" to get the model's forward distance, and in easy cases do so. (Here the Snow face-bow and its applica- tions are shown when requested; also the dif- ficulties and uncertainties in exceptional "crip- ple" cases.) But, upon the whole, 1 don't find it really practical any further than to help in getting the "average" of the measurement claimed for the principle. Rather than "argufy" with face* bow enthusiasts, I would save time and admit ignorance in its use. Some claim for it infalli- bility in all cases. I am content to accept the average the anat- omists agree on as to the actual measurement of the dead. This average measurement, we are told, is about three and a half inches; that is to say, from the alveolar ridge center in front to the center l)etween the two condyle sockets at the rear. Well, in case of long chinned "Wil- son ian" cases call it four Indies. Then tlie center of the alveolar ridge of our lower model, in front, should be, say, three and a half inches from the cross-bar of our articulator. So, as a substitute for a face'bow, if we have none, we have a simple, little, narrow, thin, 168 Greexe Brothers' Clixical Course flat piece of wood, three and a half to four inches long, with a little scallop in one end to lit against the cross=bar. TO FIX LOWER MODEL ON ARTICULATOR. To adjust this model on the articulator read- ily, I first lay the latter's lower jaw onto a piece of paper on the table; then pour some thin plaster on the paper; then set my model into this soft plaster, and apply my face-bow sub- stitute. That is to say, I set the scalloped end of it against the cross-bar of my articulator, and slide my model to make its alveolar front center even with the other end. In case of much protrusion or retrusion of lower maxillary, I "make allowances." I might and might not come nearer to anatomical ex- actness by face=bow measurement. But these are of the family of "cripple" cases, for which we hold in our sleeve a last-resort trick=taking card, after the teeth are set to this very close approximation. After the lower model has been shoved down on a plane with the jaw of the articulator and fastened, as just shown, we place the lower bite* plate onto it (the model) ; then the upper bite* plate onto the lower one, with the aforesaid jibing notches and knuckles as guides; and next the upper model into the upper bite*plate. Xext, turn the upper jaw of the articulator over, forward, over the model, not quite touch- ing it. We want to see daylight between them, to be sure there is no metallic strain on the model to tip it. Then we '11 peep under and set the guide*screw, and lock it firmly; and hold up our hand to the avowed certainty that it can't tcork loose. Then wet the back of the upper IN Dental Prosthesis. 169 model, hold it down into its bite-plate firmly without strain on articulator, and plaster it fast. Xow, doctors, the practical fact is you can't get your bite too far back into the jaws of the old-line articulators. Far more imj^ortant than the "brand" of arti- culator is the essential fact that your bite=plate (which should be preferably of modeling com- pound) just must stay to place on the ridges and at normal plat c-icc firing- stress, when taking your so-called bite. And that it must also be held absolutely to place on the models while you set up the teeth. And again all this, especially the proper strain, when you occlude ("try in'") the case in the moutli — "to see.'" If these conditions don't all obtain, then all scientific, tine-spun, high-tension theories about bites, articulation and occlusion nmst fall in prac- tice. Furthermore the teeth must be held irremov- ably to place in their investment, in the flask, while vulcanizing and cooling. Put these Greene statements into your pipe and puff the smoke at all enthusiastic Occlusion- ists — in my name. BASE=PLATES. You are all familiar with the various base* ])lates used. I presume most of you take your bites in the same plate on which you set up your teetli, and call it a "trial=plate. " Well, if such tits snugli/ so it will tirmly hold onto the gums without help, and will not slide, that will do. But, if it should move at all, which it is liable to do, especially on flat gimis, the result is the same as if a wrong bite had been taken. 170 Greene Brothers' Clinical Course Let me repeat and insist that the base^plate onto which you sticky*wax your teeth must fit down close to the model all over and not come loose. Fasten it to the model with compound round the edges. All this to avoid too thick plate and mal=occlusion. THE BASE=PLATE. There are different kinds of base= plates and different ways of using them. Formerly I taught how to make and use a "dip=base=plate." I formed it onto my model by first m etting the model and then quick=dipping it into melted basc'plate wax, twice or three times, until I got it to be the thickness I wanted my teeth*plate to be. It had the advantage of adhering closely to the model all over; and of being the thickness of my coming plate. But there was a disadvantage in taking it off*and'On model — too soft. But in later years I have found just what I want in the "Perfection" base^j^late made by the Detroit Dental ^Ifg. Co. It is one of the shellac nature; strong, smooth, hard when cool, and just the thickness for an upper vulcanite plate. After removing my hiie'plaie from the model I fit the Kerr base=plate to it in this way: I first warm the model slightly in a shallow pan of warm water. And M'hile in the water thumb*and« finger=press the also warmed base*plate down onto the warm model luitil tlie former approxi- mately fits the latter. Tlien I lift the base-plate, stiff enough to handle, and scissor it off closely to the mark-line made by tlie margin of the model*impressed onto it. This gives me the exact extent (height and length) of my coming plate*tosbe. Xow before IN Dental Prosthesis. 171 cooling I return it back onto the model, in the water, and press it to the same until it fits closely all over. By holding it in the water to do this the base-plate won't rebound and spring away from the model in cooling. Well, now, to prevent splitting in the roof during my handling I "11 fit a small stiff wire into it across and close to the rear, by heating the wire and pressing it into the base^plate. In cases of very deep arches I sometimes have to thicken my Perfection by adding another sheet onto the thin place. To weld this base' plate heat both bodies when dry and press to- gether and smooth down. SETTING UP TEETH ON BASE=PLATE. Before we removed the upper bite^plate from its model on the articulator, we sealed or clinched it fast onto the model with cleats of modeling compound, to hold it firmly to its right place thereon. And that right place was made mani- fest by closely observing the notch=knuckle fit* together of the two bite-rims. A mis=jibe would show the lower bite*plate misplaced on its mod- el; the equivalent of a mal^bite, you see. Then we fitted oin* base==plate to the model as just described. Xow we '11 prepare to set the teeth onto our smooth basesplate. We '11 make a little roll, or bar, of sticky- wax about the diameter of a very large goose-quill, and warm it and stick it onto the base-plate over the ridge of the model. We now use the Greene sticky wax. Onto this roll of sticky^wax we '11 hurriedly, but approximately, adjust the teeth; carefully heating the pins in each tooth by the side of oin* spirit flame, to assure adherence to the wax. 172 Greene Brothers' Clinical Course We '11 begin with the central incisors and get them properly located; then work on back, one by one, to the last molar. If a little time is important, this can all be done in two or three minutes. Then warming the sticky=wax and the teeth thereon, we close the articulator and simply press the approximately arranged teetli down onto the lower bite=rim, for length, and out even with its outer edge for prominence. The fixity of the guide=screw holds the jaws to right distance apart; and, if nothing sprung^ the teeth have taken the precise position of the removed upper bite=rim. We saw that in the mouth and satisfied ourselves then as to its show=length and fullness — we will not doubt it now. To thus finally adjust an approximately ar- ranged upper set of teeth requires from two to three minutes. (The art and manipulation of thus quickh/ setting up teeth by a guide^rim, regulated, by a guide=screw, is shown in detail and with spe- cial interest in our verbal Course.) The heavy, cumbersome, complicated artic- ulators are not the best adapted to this work. Xor are the weak, flexible ones at all. If you use flimsy ones, re^inforce their weak parts, by brazing on more metal. Don't rely on even your own carefulness in their use without strengthen- ing them. Xow your upper teeth are "occluded" down onto your lower bite*rim. Go on and waLV up to suit i/ou; bearing in mind that at the upper edge of your base=plate the fullness is already correct. You took your impression with proper fullness which settled that. IN Dental Prosthesis. 173 Next remove j'^our lower bite^plate off of its model, put on your lower base^plate, same as you did the upper; and the sticky^wax on it as before. And then the lower teeth approximately onto the sticky-wax as before. And then adjust them to the cooled upper ones as you want them. And then wax'up the whole lower case as you want it; of course all this time watching your guide=check screw underneath so as not to change your bite. And as I've before cautioned you: don't spring the jaw of your articulator in oc- cluding j^our teeth. After you have set j^our teeth up thus you can change the position of the front ones as you ])lease, even after setting them up to their ojipos- ing guide*rim or opposing teeth. And, to appear natural they often, if not gen- erally, sliould l)e more or less irregularly spaced and stationed. Only beware of any alteration in the length of the jaw teeth, after once set up to a Greene no=bite. They are the fixed corner^ stones of the tested relation of the natural jaws. But as to the front teeth : you can set or re-set them higher or lower. You can space them apart as far as you wish ; lean them outward or inward, or turn them around in the sticky*wax. You can regulate or irregulate them at will, so long as you don't change the guide=screw nor disregard it. Your full, double case is now waxed up. TRYING TEETH IN THE MOUTH. Xow if you fear you liave missed any thing as to tile impression (whicli is hardly probable if you have carried out these instructions) you can take the waxed^up teeth off of their models in the 174 Greene Brothers' Clinical Course articulator and "try them in the mouth." They are ready for it, now. But right here you make a blunder worse than to take the chances of not trying them in, but leaving them on their models. Whether you make any change or not in the mouth be dead sure you get your set-up teeth back onto their models exactly as they were before removal. Whatever you may spring your basc'plates, or move a tooth or lack of absolutely correct re- placement onto the models just so far will your occlusion be off in your finished dentures. You can readily see that. But, my dear doctors, even should you steer clear of all displacement of the teeth on the sticky wax, and should you get the plates back onto their models exactly as before removal you still have a dangerous gauntlet to run — several of them. IMPORTANCE OF STRESS. Think a little, doctors ; you took your impres- sion at a given stress on the soft tissues — so seldom considered by dentists. You made your model and then fitted your base^plate to it at this same strain. Then you took your bite at more than proba- bly another strain and set up your teeth at this strain on the gums. Then you "tried the teeth in the mouth" and if at all probably re*ad justed them onto the gums at still anothersstressspressure. So, even tho' you got your plates back onto tlie models as they were before there still may be a conflict of two or three different tissue strains to contend with in the case. Xow if you '11 think a moment you '11 see what a conflict of tissue strain may mean. If vou IX Dental Prosthesis. 175 want to see what it may mean in occlusion select you a mouth with soft tissues — say an upper case (a soft lower one would be still worse.) Take your impression lightly with soft plas- ter. ]\Iake your model and make your bite^plate on it. And then take a hard pressure bite: and set your teeth up to this hard bite. Then try your case in the mouth ! It will lack just as much of occluding in the mouth as was the difference between the tissue strain of the impression and the bite. Wherever the tissues gaxe way most in the straining there will the teeth strike together first when denture is finished. In sucli cases it may take a whole lot of after-grinding to even passably occlude the teeth in the mouth, and indeed the difference may be so much, here and there, they can't be ground enough to occlude them. Now, doctors, after a little side-lecture on prosthetic quackery we'll return to our case right here where we left it. We 'II shotc yon a way out of all such trouhlc. SIDE REMARKS— PROSTHETIC QUACKERY. And, my dear doctors, I will here beg par- don for a little side lecture, to insist that by far the most dentists set up their teeth too reg- ular to look natural or artistic. The distaste- ful custom is to use white teeth and set them up for the mouth to imitate ])uttons on a paste- board, or tombstones in a national cemetery. The result is that most wearers of artificial teeth look like ghosts grinning through moon= shine. It is as much of a professional disgrace, or more, for ethical dentists to let their foolish pa- tients force them to do inartistic work and ])er- 176 Greene Brothers' Clinical Course form unethical operations, as it is for an ad- mitted unethical quack to do the same thing through ignorance or greed. Hard to say, but needs no proof. Dental ethics! Humph! I have known scores of the so-called "best men" to argue learnedly and truthfully with their patients against the quackery and wrong of sacrificing natural teeth and then finally give up and sacrifice them them- selves; to do, I might say, their part to teach that their calling is no profession after all. Dental ethics:' Almost every week, and fre- quently oftener, I see mouths of good, or fairly good, natural teeth cijdoncd to make room for httle, white, glossy substitutes, to be jammed closely together in straight, even button*rows. Xor do I have to go to an "advertising joint," or "artificial^tooth shop," to see this. Then, is it any wonder that the really most difficult and highest art in dentistry is simken to the lowest grade in dental trade, when a ma- jority of even college graduates will thus "ac- commodate" the whims and ignorant prejudices of their so-called patients? Then, for the dignity of your almost sacred calling, both select and set your teeth in har- mony with physiognomy and age; yes, age of your patrons. Stand in front of the dignity of your scientific profession; at least, as an eth- ical scientific horse shoer does. You can't hire him to shoe even a mule wrongly; nor scare him with threats to go to his quack competitor. It is legitimate license to improve features, but you will never do it by such contrasts and inharmony as little, M'hite teeth, evenly set in an old grandma's mouth. You might as well put a short white skirt- let, white frilled pantelettes and sailor hat on IN Dental Prosthesis. 177 lier, and braid her hair with flowing ribbons down behind, to "make her look young." Now, do you know of any professional mod- iste who would risk her reputation and dis- grace her calling like that? Wouldn't she tell a patron with such taste to go to — to some quack for accommodation? WEIGHTED MODELING COMPOUND BITE=RIM. In most cases it is practical and I like to set the lower teeth up directly on the lower bitC' plate, or rim, of shot*weighted modeling com- 23ound, for weighty reasons; one being that I save time in not making a lower base-plate. I do this by shaving off some of the outside compound and tracing sticky=wax in its place, whereon to stick the teeth. Another reason for weighted compound is that weight helps to hold it down to place in all operations connected with it. In using the weighted compound bite^rim, to set the teeth on, be sui*e and stiffen it with wire all around the lingual side. And on waxing and shaping up a lowei- case, for flasking, always do all and everythmg on it, instead of leaving it to be done on the vulcanized denture. And make sure to scrape out on the Hngual side a good and grateful tongue scallop — most important point in a lower plate. y And here is the '"time and place" to trace-on, with stickyswax, the new (Greene "Joker," or tongue^rest, to broaden the lateral lingual reach of your plate-to5l)e, to give it more area of con- tact, for suction. Don't extend it more than one-eighth inch, nor make the plate any deeper. And don't put it in fi-ont. Say, doctors, when you get to using weight in lower bite-i)lates and base-plates, you'll feel. 178 Greene Brothers' Clinical Course and do, as tlie tenants of the Duke of Argyle once did. He advertised for the l)est way to make them grateful and to praise him, and the result was that he put up back=scratching posts at close convenience all over his estate. Then all the ])eo- ple scratched their backs every day and grate- fully rejoiced aloud: "Blessed be tlie Duke of Argyle!" l^ea, doctors, in severely needful cases you may catch their spirit and put up great sound' boards to re-echo: "Blessed be the cranky old farmer dentist from the 'Show=me' State." If you don't, you'll be ungrateful for this $]00 ])()inter. (A class=man: (xive us more about the "joker.'") All right, I'll give you more. AV'elJ, to make room for this accommodating lingual support, the jaw teeth sliould l)e somewliat high, or long; and, that they may be so, the toucliing ones above must be correspondingly short. The rule, then, is to range tlie upper molars rather upwards and make the last one about as short as you well can; then, of course, bring up the opposite lower ones to correspond. The exception would be when the upper jaw teeth need to be long, to hold the cheeks out. But, nevertheless, long molars, especially long last ' molars, are detrimental to comfortable wearing of upper dentures, anyhow. Dr. Geo. A. Wilson, the eminent prosthetic specialist, of Cleveland, Ohio, contends that the up^turn in the range of an upper set of teeth should be confined to the final molar; leaving the rest on a plain, occlusal line. And, strictly speaking, philosophicalh) he is probably correct. I can't say anatomically correct, for anatomies vary much in this respect. I IX Dental Prosthesis. 179 STILL MORE ABOUT THE "JOKER." There are some cases where the lowei- teeth, for one or more reasons, can't be made long enough to provide ample space for a sufficient cut-away for such frictional tongue support, our tongue scallop. In such cases, 1 come to the rescue with a universal, ne plus ultra ''joker." This consists of a narrow, lateral addition to the lingual edge of the lower plate on both sides of the mouth — not in front. By vulcanizing (if a rubber plate) such an extension to the ])late, at right angle with its lingual walls, and then scalloping out some from both the wall and extension, a sufficient tongue* rest can be made, in almost any case, to hold down a lower denture; even if it had no other means of retention. Of course, the extension should be made and the scraping done in tlie wax; never much in the vulcanite plate. However, in swaged or cast metal plates, pro- vision should be made for the joker first in the impression, and conseqeuntli/ on the model; a stunt requiring skill, experience and persistence. ANOTHER REASON FOR THE JOKER. Another Aaluablc advantage in the joker, other than its ])roviding means for tongue force, IS that it adds area to atmospheric contact and thereby helps to give the denture more so=called "suction." But beware of adding depth to the plate's edge, which was settled in the impres- sion, in the outstart. (See Index V.) It must extend laterally, and sometimes a little angling upward, to accommodate a roll of soft, moving tissue under the tongue. When the joker is properly adjusted, it sets, in normal cases, do\m onto and into the sublin- 180 Greene Brothers' Clinical Course gual saliva bed, ever present in healthy mouths, giving the plate the action of a duck's web* foot in a mud=puddle. Without it, such a plate might be as a chicken's Avebless foot easily working up'and^down in water. The joker should extend in length, say, from about the anterior of the first bicuspid to the posterior of the second molar; and in width, say, oneseighth to three=sixteenths of an inch in the center, rounding off gradually to the ends. While I advise usually about this width for this tongue=rest extension, I have put them on twice as wide, with little or no discomfort to the M'carer. In one case, a dentist misunderstood me and made the extension half an inch wide. His report, a month later, was that his patient "kicked like a bay steer for ten days"; but aft- er he had "cured" ("tanned") her mouth with white«oak=bark ooze, it got well; and "the plate sucked down like a goose's foot in mire." THE JOKER A NEW IDEA. The idea of a tongue scallop is not wholly new, though the scheme never has been prac- tically introduced to much extent until this private Course of Instruction has been before the dentists in a number of States, mostly in the far West and mid^West ; now about fourteen years. But the idea of a lateral extension to the lingual rim of a lower denture, to set onto and into the saliva pool under the tongue, and thereby cause suction, and to furnish leverage for the tongue for mechanical power, is original ill this Course, so far as I know. And I remember that it took years to de- velop active courage from the inspiration to IN Dextal Prosthesis. 181 warrant a trial of the theory. Aiid I remem- ber how a few sore mouths ahnost frightened me for a while away from this most practical of simple prosthetic improvements. It is a simple matter to scoop out tongue^ rest room in modeling compound or wax; and no difficult one to add the joker in wax in "waxing*up.' But care must be taken to do it all philosophically; and especially to finish so as to leave no roughness whatever. And even at the best the mouth will some- times require astringent treatment, taking time to "tan" the parts so as to immune them from frictional soreness. Among the numerous astringent remedies I liave used to treat sore mouths and "tan" the membrane to immune it from tenderness, I have found nothing less disagreeable nor more successful than simple oak=bark ooze; that is, reduced tea from, preferably, white=oak bark, with a very little essential oil of some sort in it to prevent fermentation. But, withal, the joker is the card that zcins, even when all others fail, to hold a lower plate in place sufficiently for practical use. (In five years a thousand men will probably claim its invention.) But don't get the idea, as some have done, that my joker is an attachment to the plate. It is simply an extension, of the same material. THE LATERAL, OR "SHEEP=BITE," MOVEMENT. Well, here we have a full set of real teeth Ave've set up by our no=})ite rims in this Old PlainsIJne Articulator. T use it for its sim- plicity and popularity. We first set the upj^er ones to the lower bite^rim. Then we set tlie lower ones to the 182 Greene Brothers' Clinical Course upper ones. They come together, as a whole, just exactly as our no^bite rims representing them did, "compensating curve" and all. But so far we have only a square, perpen- dicular strike; at least, without any knoicu close' occluding horizontal fit. But, in crush=grind- ing, the lower jaw, you know, has a little lat- eral motion; sometimes nicknamed the "sheep- bite," and the "quid=bite." While this lateral motion is never as ex- treme in the mouth as is generally shown as a possible movement of patent articulators, it is always there, to some extent, in uriimpeded natural masticatory action. And, of course^ artificial teeth should be adjusted to accommo- date the full natural side-grinding action. The wearer will seldom get the ])est without, say, an eighth of an inch sideways play. Now, the question is: How best to get this natural, lateral motion in an artificial denture? The claim for numerous articulators on the market is that they impart this and all other natural movements exactly to the artificial den- ture, including the anatomical relations of the teeth. This is indeed well. But granting the competency of the ma- chinery itself, there is a problematic combi- nation of ticklish factors in the way of prac- tical application. So the exact transference "depends." It depends on (a) whether or not the dent- ist has the exact natural bite — very doubtful by usual methods: and (h) whether he has this exact natural bite on the articulators exactly as it was when tested in the mouth; and (c) whether he knows the exact movements of that particular jaw; and (d) whether he sets IX Dextal Prosthesis. 183 his machinery exactly to those (pro})ably vary- ing and erratic) movements. I don't mention these problematic points to hyper*criticize claimants for perfect anatom- ical articnlation and occlusion, who so seldom give all these essential facts in their case. I do it to put you on your guard in the use of an I) articulating device. Whether true or not, I'll here assume they can't (for I can't) always organize all these factors into practical operation for the exact- ness claimed. We'll then go on and do at least the next best thing, under the circum- stances. We'll make the closest approxima- tion that artificial machinery can provide, and then make the jaw itself its own articulator in the finis. THE COMMON, OLD PLAIN=LINE ARTICULATOR IMPROVED FOR ANATOMIC WORK. I have here an old plain=line articulator that I have so im])roved as to give, I think, as ap- proximately the average anatomical movements of the natural jaw as any Fve seen. You'll huigh when you see the plain, humble,, slandered old lady in fashionable dress and in service on the modern anatomical stage. Why, she's joined the Leetnre Bureau! My! isn't it a bou(piet=deserving achievement to have "dis- covered" the mud-covered old diamond! See here, doctors, with this native cross-bar she shows her plain o})en'and=shut, unassum- ing j)osition; her straight up-and-down way of doing. That's "before taken." Xow, look again! By a simi)le twist of my fingers I'll remove her old tight=jacket cross= bar and insert a freer (smaller) base of action; a simple, common 8=])enny nail that I found 184 Greene Brothers' Clinical Course on the sidewalk, trampled in the dust of hu- miliation by the thoughtless multitude — only an 8=2Denny nail, rusty from ill=treatment, neg- lect, and inactivity. But humble as the common nail is, it en- ables Madam Old Plain Line?' to sweep the ana- tomical horizon to the right and to the left in graceful, competitive waltz. What an honor to the down-trodden old nail to have enabled the long'guyed old ]Madam to impart such lateral "sheep-=bite" benefit to toothless humanity ! Well, let 's stop praise, and ask the old thing to prove she 's from ]Missouri by "show- ing" us. I'll be her humble servant. Watch me. I '11 baptize her upper jaw, teeth and all, "into" cold water. Then I '11 give the teeth of her lower jaw a warm reception over our cheerful spirit=lamp till they are ready to move in the right direction. See! Xow I clasp my Mhole left hand firm- ly over her cold upper jaw and hold it tightly all around; then fully clasp her more tractable louver jaw, in tlie same way, with my right hand — 'that lifted the lost nail from the mire and the clay to glorious usefulness. With the upper teeth cold and set in stolid firmness, and the lower ones warm and willing to yield to their superiors, under pressing cir- cimistances, I '11 give the command to "Side- wiggle!" And all on a sudden the teeth be- low have "exactly" Avaltzed themselves toward those above them, to practical anatomical jux- taposition — if we 've watched the set=screw and haven't bent the metal jaw. We now have lateral occlusion, also. But the action of ]Madam Plain'Liner isn't up=tosdate yet. She must now set her face in IX Dextal Prosthesis. 185 another direction. I'll further help her up in the 2^opular anatomical world. Watch me close this time. THE FORWARD BITE MOVEMENT. I '11 take a small, parallel=round mouse-tail file, the size of a 6*penny nail, and make a small "condyle path," or slot, running out from each one of the four cross-bar holes, at regulation angle; on both sides of the articulator, of course. These slots extend out about one-sixteenth of an inch from the main cross-bar holes; those in the upper jaw extending forward and those in the under jaw rearward. The two condyle slots (a i)air) together in action give the lower jaw a range=reach of, say, one^eighth of an inch; or more, if wanted. And as much more as you Mant, according to depth of slot. So with a still smaller nail, a 6=penny, that will move in the newly provided "condyle path. ' she can now reach out and bite cud to on her front teeth — ^like "Suz^an ]Moriah" could. We peep imder and see that our '"compen- sating curve." made for other purposes, and incidentally for this occasion, is intact. The rear molars still hit together "automatically." By further extending our little-nail slots, 3Iad- am Plain=Liner could make just as exaggerated protruding movements as any of her competi- tors. But she doesn't care to distort merely to show off possibilities. EACH MOUTH ITS OWN ARTICULATOR IN THE FINIS FURTHER ILLUSTRATED. Well, now, if we want the exquisite of nat- nral anatomical occlusion, we'll first finish the upper set; and then take the lower set (which 186 Greexe Brothers' Clinical Course stays down from musclestrimmed non-resist- ance, weight, tongue power, and atmospheric pressure) and adjust the teeth, in the mouth, to the finished upper ones by "each-mouthsits own=articuhitor-in5the-^«/.9" action-to be shown a few minutes later on. If we can control the one seldom-thoughtsof, all^important matter of strain in the lateral, sheep=bite action, our anatomical occlusicni will be mighty close to perfection. And t:his is what we propose to do. CLASS REQUESTS DIFFICULT AND "CRIPPLE"=CASE ARTICULATION AGAIN AND FURTHER EXPLAINED. ^Vell, to review: In cases of pronounced deviation from the normal (as in extreme pro- trusion or retrusion, where even the '"average" is evidently out of the question: where the three-and=a=half=inch measuring^stick wouldn't make good, nor the condyle socket be tindable, for face=bow application ) — we can resort to our already mentioned process of real, natural auto- matical articulation: that is, to make the mouth itself its own articulator in the end. AVe can take our regular non=moving no^ bite on a modeling=compound bite^plate : which would give at least a close approximation to the true bite; probably a correct one. We 'd then soapstone the occluding edges of the rim to prevent adhesion, and warm the lozcer one slightly, so as to mash to the upper one, not warmed: or to the upper teeth, if there, natural or artificial. Then we would quickly put the bite-plates into the mouth and have patient actually chew on them in all directions. This would mash IN Dental Prosthesis. 187 the soft lower rim off fairly close to the way the teeth should be set up. Xext we would place the bite, as a whole, ill the articulator in a way to see it make as nearly as possible the same movements the jaw made in masliing off the lower bite=rim. Future generations may discover some way to breathe the })reath of life into metal jaws; but even then they'll have to also discover some way to graft bite=plates onto them, that their maneu- vers may "make good." In some cases I 'd face my lower bitesrim with soft-stone (plaster one to pumice=stone three) for easier abrasion. (Index S.) If patient had natural teeth above, we would use a model of them; if artificial ones, either a model of them or the denture itself, in the articulator. In this kind of work it is best to use mod- eling c()mi)()siti()n in liolding the models in the articulator, so that, if necessary, it may be soft- ened in the slow adjustment, sometimes inev- itable in ariculathig bites. We 'd then set our upper teeth to the lower bite=rims, to its (inatomicaUy mashcchoif or rcoru- uf .surface, carefully. Then set up the lotcer to the upper ones, as wanted, anatomically, of course. The teeth, set up in this way, must have very close approximation to their needed positions. We would then wax up our case, not for- getting our tongue^rest arrangements: and cool both ])lates while yet on the articulator. Tlien take them off tlie articulator and warm the lower teeth sliglitly over a hand - spirit ' lamp fiame, just enough to render them movable un- der some pressure, in tlieir waxed environment. 188 Greene Brothers' Clinical Course Then quickly put the plates into the mouth and have patient go through all the chewing movements, actually on the teeth themselves, for adjustment. This is the "finis/' Barring the stress feature (always contain- ing an element of guess=work without the press- ometer) , this will give a practical "automatic" articulation; especially if the upper set is fin- ished before the chewing adjustment is made. It is very particular work to use the press- ometer on the waxed-up teeth. For then the reduction for the over=strain must be made by warming them and pressing down on them to exactness, tchile tcann, in their wax investment; instead of cutting or filing off the compound, as shown in demonstrating our pressometer. In taking a bite for an auto=articulation like this (if in absence of the pressometer), it is best to soften the bite I'im well and bite lightly, if over soft tissues, to avoid getting the teeth too long, in the first place. There are many little varying details, es- pecially in these unusual cases, that you will have to work out and apply yourselves. But the sum^total of the operation is to make each individual mouth in difficult cases to be prac- tically its own articulator. And, to do this, you '11 have to take some pains to train your patrons how to do their part; and have due patience with their awkwardness. You have gained the victory when you can do this. While some of this fine=point work would be superfluous in plain, easy cases, it 's never- theless mighty handy to resort to "every-mouth* its-own-articulator" in unusual ones. But for Old Green's sake, now, don't get this mixed up with the common old "try'it* insthe*mouth" uncertainty, where light, guess* IN Dental Prosthesis. 189 triiimied lower bitc'plates jump up and around like mice in a training-school, preparing for a 2)us.sy s cat invasion. Bite=plates and set = up teeth must stay in place^ to make good in the jinis. When understood, there 's little kind^ship be- tween the two last^resorts. (X. B. — This is all shown in detail, on the articulator, in the verbal Course.) NEW WAY TO TAKE TEST NO=BITES, IN NO=HANDLE BITE=TRAYS. It has taken me many years to invent and put into 2)ractice what I'm now going to show you. It is a combination impressionsand^bite tray, with short, movable handles. With the handles on, I take my impressions in modeling compound, to the finish test, just as shown in my first lecture. After the test, I cool them thoroughly in tlie moutli; then remove them therefrom and cool again, and also remove the handles. Then add a modeling=compound bite=rim onto the metal tray, on reverse side from impression. The test impressions are now also bite=plates. We '11 put the upper one in and out, as such, and trim it; first as to the fullness we want the lips and cheeks to show, as you 've been shown. And then trim as to the show=length of the teeth, as you 've also been shown. Then we '11 take the lower case and trim it; but this time first as to the slioxi' ' length of the teeth, as you 've been shown. Then, to trim it off even with the upper rim, we '11 take our first tired^rest bite, to serihe it for that purpose. Then trim it off to the scratch: and go on and finish it all as a no-bite, same as you have been shown. 190 Greene Brothers' Clinical Course Now, we '11 fill our impressions, or bite^plates, whichev^er we may call them (separately). And when the models are hard, we '11 j^lace the no= bite, guided by the jibing notches and knuck- les, in the articulator. And from this on we '11 finish the case just as has already been demon- strated. The advantages in this newest invention are: that we can remove tlie handles from our trays, to better get the fullness of the lip and cheek, in our test impressions; also that there is no chance for slipping and changes in articulating the bite, nor in transferring it from and to the models. Also bite=plates can not warp in a metal tray, should they get w^arm. Then, we save the time of waiting to make models and the taking of impressions of them for bitc'plate purposes. In this bite'tray method we can still use the Greene ready-made metal models, in filling our impressions, the same as before, if we want to. And, for certainty in results, that always pays. IMPROVEMENT IN "BISCUIT" BITES. Before we invest our case, from the artic- ulator, I '11 now fulfill my promised im})rove- ment in "biscuit" bites, to be used should you M^ant to go back to the old habit for "old hab- it's" sake. Take your "mush=bite" in the usual way, but in modeling compound, using your wood guide^stick for (approximate) width of bite. Xine chances to one, you 've taken it (the impression), or some part of it, at too strong pressure. Xow to approximately correct this, just pour some thin, creamy =like plaster in the upper part, shake it mostly out, and take it IX Dental Prosthesis. 191 again, just as before, but liglitly: this to re- lieve excessive strain, if any. Xow add to, or take from, and trim for the feature=test. with lips closed. Then take the lip= Ihie (laugh=line) and mark for the showslength. of the teeth, all around, not forgetting the short last molars above — 'for reasons explained. Then with a frame-saw cut the "biscuit" in two at this line; and go on and take the tired^rest bite, or no^bite, with which you are familiar, the best you can. under the unfavorable conditions. This will by no means give you perfection, but, if the im])rovements liave been added right- ly, there will be far less guess-woi'k in your l>ite and its results. FLASKING THE CASE. You are all familiar with the seemingly sim- ple matter of flasking the case: but there are some usually neglected pohits that I would "hol- ler" in tlie ears of men and whisper in the ears of lady dentists — for best attention. First of these is: See that the metal rims of your flask come together without rocking the least l)it: and see that it 's no bit of old ])laster that prevents their rocking: for. if so, it may disintegrate and come away. Second: See that your models, if plaster, are trimmed down to not over a quarter of an inch in thickness: and then, to raise them u]) to needed elevation in the flask, use under them some non=changeable filling of metal or its etjuiv- alent. T keep a few flat metal supports, vary- ing in thickness from one'quarter to three- quarters of an inch, and set them witli tliin ])las- ter on one another, if more than one is needed. 192 Greene Brothers' Clinical Course Do this even with metal models where the}'^ need elevating. For, though the disintegrating and mashing of plaster under a metal model will not affect the fit of the plate, it will affect the articulation. Then we mis - attribute the mal*come=together as a ''wrong bite." And here, doctors, let me impressively sug- gest that if you can at all spare the time it will always pay, especially in soft mouths, to stop here and vulcanize and finish your upper set; and then re-occlude the waxed-up lower case to it, anatom- ically, in the mouth before flasking it. But to our flasking: Use only good plaster, mix as carefully as in making a model, to avoid disintegration; then wait for perfect hardening. PACKING AND VULCANIZING. To open the flask, warm it over a small spirit flame, and only enough to provide against breaking the model. When it is warmed through from the under side till its top is of good flesh temperature, it is about right. Then the wax inside isn't melted fast to the plaster. Open first at the opposite point from any under^cut in the model; that is, usually, prize first at the heel. When apart, quickly pull out all tlie wax that will come away. Then dip in cold water a minute, when you can easily and cleanly flip off the thin flakes of sticky= wax, loosely adliering to the teeth and plaster. It is better to get it out in this cold way than to steam it or boil it out; as no wax then soaks into the plaster, or sticks to the teeth, to interfere with proper vulcanization. Bear in mind that it may be even invisible wax. left on the teeth, that causes softness and difliculty in finishing the pink rubber about their necks. IX Dextal Prosthesis. 193 Use none but the very best vulcanite. Dentists save money at costly risk of their reputation in using poor materials. They "fake," maybe unwittingly, on a mighty small financial scale, in using poor grades of rubber — in fact, poor grades of any other material — in dental work. Pack carefully; use dry heat; squeeze light- ly, and close very slowly. And, no matter how experienced you may be in guessing, you 'd better use the trial cloth, especially in lower cases. Use pink rubber in the center of thick upper rims and weighted rubber in thick lower ones to prevent jjorosity, excepting in front. The trial cloth is that which comes between sheets of rubber. Don't wash the starch quite all out. Then kee]) it wet. lest it may stick to the hot, soft vulcanite. HOW TO VULCANIZE. Only a few points here; and still fewer of them new. But you are a rare flock of ])ros- thetic birds if some of you don't need to have some, even of the old ones, re^suggested to you. "He that hath ears, let him hear" — it again. Then vulcanize at the lowest point possible Avith your tried- and known thermometer and vulcanizer. Xot all thermometers register tem- perature alike. Xor, indeed, do all vulcanizers Avork alike. I have carefully changed the same thermometer to different vulcanizers and found pronouncedly different results. Then test your vulcanizer often enough to "know for yourselves, and not for another," just how it works. Then, in practical use, run it at the lowest vulcanizing temperature and long enough to a tougli^liardness, and not a brittle one. [13] 194 Greexe Brothers' Clinical Course Then leave it in the flask, but not neces- sarily in the vulcanizer, for several hours. Yes, for several hours, even after it has cooled. Leave it in the flask over night if you can. And don't accept this advice as a whimsical notion of an old = timer without reason. Each package cf vulcanite sent out to the dentists at its first introduction contained this advice and warning. I '11 not attempt to give you the chemical reasons, but the practical fact is that rubber, it seems, doesn't complete its crystallic or other hardening arrangement during the cooling pro- cess: and, if taken out of its imbedment too soon, it is liable to warp. Then the consequences (which may come even after worn awliile) are often attributed to '"change of the mouth." ElV- perimcnts in my oicn mouth prove this. And this is particularly true where scraping and tiling are done to the extent of bringing a ^^■eake^ grain texture to the surface. So, let your ]jlates '"season" several hours, when you can. ]Make quick plates only in cases of need- ful hurry. I wish I had a Gabriel's horn to toot to tlie prosthetic dental world not to boil their cases and soften their plaster models before squeezing too-ether: and then not to use much force, anv- how. Xinetv per cent of vou need this strong- talk. DISHONESTY IN RUBBER PLATES. I know mainly three reasons for brittle rubber plates: (a) absolute Dishonesty; {b) Carelessness, which is a reckless child of Dis- honesty: and (c) Ignorance, vdiich is a legit- in^.ate offspring of Carelessness. IX Dextal Prosthesis. 195 When a vulcanite plate breaks, especially if in the mouth, the dentist ought to be re- sponsible for it. For it is next to impossible to break a pro2)erly made plate of really good stuff; and it is a dentist's duty to test his ma- terial before promiscuously using and selling it. It Mould pay you all, and at the same time be a good "educator of the people." to make and keep several toothless plates to jmnp up= and=down on, and to throw against the wall, to show your patients zchat you can do; and then do it lionestly. I insist that a pro])erly made and properly titled vulcanite plate, of good ma- terial, zcill not brcaJc in the mouth; nor will it out of the mouth without considerable effort. The '"cowshorn"" samples sent out by the man- ufacturers are proof of that. There are numerous coverings for plaster models, to prevent the usual deterioration of rubber in vulcanizing contact with gypsum. There are some excellent liquid "glosses." Af- ter strongly advising those of you who dont use anything, to use soincthins!;, I will state that 1 still use thin tin^foil. preferably number four. And even thni gold foil is not too expensive for the benefit, if no tin is at hand. The claim that thin foil, placed evenly all over a model, will change the fit of a plate, on flesh tissue, is high=grade theori/. backed by low-grade faet. The model is at first })ainted with very thin varnisli, and the foil then hurriedly smoothed on with a connnon shaving=brush. Then the foil is as liurriedly smoothed over with pulverized soajjstone on the brush. ( We licked the foil on before the days of dangerous microbes.) If for no otlier one of several good reasons. I would thus cover my i)laster models to bring them out of the flask clean and save time in 196 Greene Brothers' Clinical Course not otherwise even half' way cleaning them of tightly adhering plaster. Plaster can he very quickly scruhhed off the foil, and the foil as quickly eaten off the plas- ter, by a thin, hasty amalgam, made in the hand, of tin^foil, or tobacco^foil, and mercury. The fact is, a rubber plate should come out of the flask clean, fairly smooth, and almost finished. It should need no trimming, other than of small excess extensions; no filing, nor scraping, as to its shaping. And no grinding. LAST FINISHING CARE IN ARTICULATION. Ten to t^venty minutes will finish our double set of teeth, after out of the flask, if we have modern lathe machinery. We '11 slip them into patient's mouth to see whether or not they come together properly. Xor will we jump to any hasty conclusion about it; for we have all been fooled in that way. We have quickly concluded articulations w^ere all right, when a few hours, or days, ]:)roved otherwise. And sometimes we have hastily said to ourselves, if not to our patients: ''They are all wrong; you hit wrongl}", and I 11 have to make them over;" when a little time showed a mistake, in our favor. Xow, to forestall the like of this, we '11 take a regular no^bite on the finished denture to see for sure about it. If it proves, all is well. If the teeth don't hit rightly, after all these precau- tions, it is ninestO'One on account of some change after in the flask, during vulcanization. But it can't be much wrong; nothing that can't be corrected. So, if needs be. we '11 cor- rect it. And here is the way we '11 do it. We '11 trace a little very thin smidgen of plaster on top of the lower teeth and take an- IN Dental Prosthesis. 197 other no'bite on it. Wlieii the plaster is hard, we '11 take the teeth out of the mouth, and, using compound or bees* wax instead of plaster, we '11 fasten them in the articulator; the plaster on the teeth being our articulating guide. In placing them in the articulator, we '11 be just as careful in the use of the face-bow, or measuring'Stick, as we were in articulating the bite in the first place, and for the same ex- plained reasons. (We '11 now go to the labora- tory, out of patient's sight.) When these finished dentures are in the ar- ticulator, we '11 remove the plaster from be- tween them, bring them together, and look un- der and see what has to be ground off. A few touches with tlie carborundum wheel, and the worst is off. Xow we '11 follow up with carborundum sand^paper, by sliding it be- tween the teeth until eacli one will touch its opponent, even to the holding of the thinnest tissue paper, if we so wish. But in this final grinding we mustn't neg- lect to give the lateral motion to the articu- lator, to wear the teeth off to the regulation lateral quid=chewing attrition. A STILL FINER LAST GRINDING TOUCH. A still finer last toucli may be made with carborundiun grit. Stick a strong piano'wire coil-spring firmly onto the extending point of the guide screw of the articulator, of a length to ])ush the teeth to about an inch apart. Then put ^a "bumpswheel" on your lathe s])indle and hold the articulator so the bumps will strike it on to]). The spring will open the jaws, and the bump (one or more) on the wheel will close them. Thus you '11 have a chewing^ machine to — chew too fast, if vou don't watch out. 198 Greene Brothers' Clinical Course TIlis wheel maj^ be of felt, soft wood, doub- led sole-leather, or soft rubber; and should be from four to five inches in diameter. One bump is enough. All you need to do, to add this last exquis- ite touch, is to feed a mixture of carborundum grit and glycerine, with a small brush, while you wabble the jaws for the quid ' motion — ^^and whistle "Yankee'DoodlesDixie" ten or fifteen minutes. Some dentist, ^vithout reflecting what nerve mixture the average man or woman is made of, has notoriously suggested that this grit - grinding process should be done in the mouth ! ! ! "The Great G. Whiz ! Who is he ?" BETTER DEFER FINAL ADJUSTMENT. But, doctors, it is best in cases of unequal tissues and soft mouths to let artificial dentures be worn a few hours, or in bad cases days, for adjustment, before those final touches in oc- clusion are given. It 's best, really, to let all artificial dentures "settle" well before the final occlusive grinding — if they need grinding. INSTRUCTIONS TO WEARER OF ARTIFICIAL TEETH. "Now, JNIadam, you ha\T a set of teeth that stand the best regulation test. The upper ones stay in your mouth witli usual movements of face and deglutitory muscles. "The lower ones stay in place with these ordinary movements, and you can hold them in their extraordinary motion. "The dentist has done his part faithfvdly to the finish. Will you do yours the same? If so, all will be well, and you '11 have comfort and benefit that can't be measured by money. IN Dental Prosthesis. 199 'But it maij require some auto=suggestive determination, perseverance, and practice to reach the goal. ^ First: Use your own favorable auto-sug- gestion, and reject the adverse suggestions of others. This is the first and generally the worst thing wearers of new teeth have to meet ^\itli and to overcome. "Some may tell you your teeth are too short, and others tell you too long. Some ma}' sa\^ they fill your mouth out too much, and others saj^ not enough. Many will insist that your teeth are too dark, and some few say too white; and so on. "^Vithout their pre ' auto ' suggestion, few women, or men, under similar circumstances, wouldn't be disconcerted as to their hats or coats. "And hardly one woman in one hundred who could not be discomposed, and run in off the street, if strangers were to look at her. and several of her friends should tell lier that her skirt was ridiculously short; even in face of the truth that it was too long. Indeed, any discussion about the matter would disconcert her. Of course, you are an exception!! "Now, Madam, your teeth are right in size, style, and color to suit your features; your oxi.'n features. "I have made them to look like your per- feet natural teeth would look at your peaceful stains of earthly incarnation, sometimes vulgarly stated as your age. Beware especially of what your inartistic friends may say as to their sliade. "If they were lighter in color, the contrast would make you appear ridiculous, and, in fact, the older. They give you the appearance of a })reserved lady of your sweet sixty. So, ac- cept no suggestion to the contrary! 200 Greene Brothers' Clinical Course "Aiid, now, for learning the art of che wing- on them. This conies much more naturally to some people than to others. But all have it to learn; and most of them by progressive degrees. "You '11 first have to learn to chew on both sides of your mouth at the same time. This is to cause your gums to settle and adjust them- selves to both side alike. Otherwise the plates Avould settle the more unevenly as the usual adjustment took place. "You will easiest and quickest learn on thin slices of boiled ham or tender dried beef. Put a piece on either side to place and clietc, and chew, and chew, and swallow and chew. "Go on and 'Fletcherize' till meal=time, and then take the plates out of the mouth. But, when the meal is over, go at it again and chew sliced meat or its equivalent as before, on both sides at once, until meal^time again; and so forth. "Keep this up persistently till you can chew a little better icith the teeth than mthout them. This will not be many days. Then, when you feel their need and benefit, leave them in dur- ing meals. But then, at first, use only small bits, if of promiscuous food. "In a week or ten days, you '11 begin to use them pretty well; and in a mouth, or less, perfectly. "Heed this advice, and you '11 have no trouble; ignore it, and your road to success may be longer, if not beset with difficulties, both imaginary and real. "And now, further, Madam, to forestall all ill suggestion, auto or otherwise, I '11 here and now clinch and settle the matter of mastica- tion. I have here some of the thin slices of ham and beef I 've advised, and will give you IX Dental Prosthesis. 201 a practical start that will be unquestioned and satisfactoiy. [Here she is made to chew on both sides at a time until she is satisfied.] "Now, Mrs. Jones, you have chew^ed several minutes without trouble. Xext time it will be easier; and the next time still easier; and so on until you '11 forget that your teeth are shops made, at all. "Your teeth, at first seemingly naughty and worrying, will in time behave admirably from your persistent, but serene, will-power. "Your eyes will renew their suasive dancing. Your cheeks and features will regain their full- ness and flush of the sweet ago — ^^as much as the Goddess of Duration thinks best for you. "And even your inartistic friends will ad- just themselves to your regenerated looks and feelings of sweetness. "But, finally, ]Madam, I beg and implore you not to accept tliis extra fine, artistic set of teeth merely on financial account. In such a case, money is vulgar. I 've taken all these pains for your happiness and my own glory/' NO=BlTE OF A PLAIN UPPER CASE. iBeing through with a plain full "double" set, we '11 now take up this single, simple, up- per, toothless jaw, articidating with a toothful loM'cr one. If, however, a few lower teeth were lacking, the bite would be similar. We manage a similar case one way, and a good way, in our "advertiser's quick-step." (Index A.) And another in the Greene quick- step. (Index G.) Xow we'll have two more ways; the first one being my own once "regu- lar" way. T have it here on this same old* fashioned articulator with anatomical attachments. But 202 Greene Brothers' Clinical Course the same princi])les and points will apply on any other articnlator. Take yonr model, on which you intend to ^ ulcanize your plate, and soapstone it to pre- \'ent the impression material from sticking to it. Then take an impression of it, without a tray. Work the impression down thin in the roof, and build it out full enough and down long enough to allow for trimming, both as to the fullness of lips and the show^length of the teetli. It is always easier to trim off than to add to; even by our new w^ay of tracing'on modeling compound from our "blessed" tracing- sticks. The projecting shoulder on the model will l)e your guide as to the thickness of the bite^ plate's rim at the top. Xext trim for the ap- proximate fullness of the outer lip lower down. But exactness here isn't really of much im- portance, since the upper teeth have to come together within certain relations to the natural lower ones below, anyhow. Then next comes the show*length of the teeth, where no guess ^work is permissible. ]Mark the lip=line, harmonizing AA'ith the laugh* line, and trim the bite=]3late down to it. Cut in front only, and for the width'Space of, say, the four incisors; and, if needs be, including cuspids. Then have patient repeat vigorous smiling until you 're sure of the proper show* length of the coming teeth. If you can't see well, you can paste a strip of white paper onto the bite*rim, down to where you have trimmed it, to show how long the teeth would show; or you could even stick some in- cisors onto the compound, if you wanted to. Next: Cool the trimmed portion in front and warm the top of all the rest of it, rearward. IN Dental Prosthesis. 203 Then have her bite onto this softened top until the trimmed, hard front strikes the lower teeth and stops the jaw. If this should require more tlian once warming, repeat it, of course. When you have had patient mash off the bitc'rim for the show^length of the teeth, and have removed the sidc'inashed surplus, you are ready to tire her jaw and register its natural position; that is, to take the no=bite, which is some different from the full set, in this: Instead of testing it by notches and knuck- les, as we did in the full case, you '11 do it in this way: Roughen the bite^rim in front, back, say, to the place of the first bicuspid, so that warm compound will stick to it. You '11 have a little roll, or thin slab, of this in hot water ready for use. And now for the non-lateral, perpendicular, minimum short bite. Is it nec- essary to sliow that again:" (Class: ''Yes; go on and give it again.") THE NON=LATERAL, MINIMUM SHORT=BITE, OR "NO=BITE," DESCRIBED AGAIN. "Xow, Madam, suck this bite^phite up tight- ly; then let your jaws approach very slowly till your li^^s touch together lightly and the lower teeth almost touch the rim. "There, there, ^ladam! hold just that way while I coimt ten; then snap and hold fast. One, two, three, four, five, six, seven, eight, nine, ten — snaj) and hold!" The jaw^ was at tired-rest, and the remain- ing space too narrow to admit of unintentional, lateral side-motion. While she bites down, I take my strip of ready warmed compound and press it firmly against the roughened bite*rim (above) and also against the natural teeth, below. 204 Greexe Brothers' Clixical Course The rough surface on the bitesrmi will hold it till I get done; and the saliva on the lower teeth will prevent its sticking thereto. I Mill now take it out of the mouth and, Mitli a small, hot knife=blade, stick this con- necting strip, at both of its ends, more tightly to the roughened rim, lest it might come loose. The two together, the strip and the bite* rim, look like a single piece into wliich she has bitten. But the biting was done (at short range, avoiding lateral motion) before the con- necting strip was pressed on. Xext we "11 warm our knife=blade again and shorten the connecting strip off down almost even with the edge of the bite - rim proper. We '11 leave just enough to show a little of the sockets of the lower teeth, into which these teeth are to enter when we make our no^bite test, later on. Well, the connecting strip has now been shaved off, and on purpose that we can see the ends of the lower teeth enter the shallow sockets: or else fail to enter, if the no^bite should be wrong, when we make the test. So we are now ready to test our no=bite. THE FULL UPPER NO=BITE TEST. "Again, ]Madam, give me a test=bite on this. Close slowly just as before; only this time keep your lips apart so I can see your teeth enter their little sockets as you close. "Close slowly, slowhj! There, now. your teeth almost touch the rim. Hold till I count ten: One, two, three, four, fire, six, seven, eight, nine, ten!" I looked up under her lip and .sr/tc the ends of her lower teeth smoothly slide into their shal- low sockets on the edge of the upper bite*rim. IN Dextal Prosthesis. 205 "Xow, ^ladam, that 's correct. Let me try it again." We test again; and the fact that the jaw ucas at rest is confirmed by three or more tire= test witnesses. If the teeth had missed or failed to go into their sockets smoothly, a few trials would have shown at which one of the three times the jaw had moved sideways. In such a case, the nO' bite would simply have to be re^taken until the case icould prove. But the proof would be un- questionable. But we are here granting a very remote probability; for, if this operation is rightly done, it will not fail once in fifty times. Of course, this "rightly" includes receptive in- structions and, sometimes, some training of patients. And here let us lament that dentists gen- erally know so little about methodical sugges- tion to their patients. (A fourth lecture will be added to this Course on "Scientific Sug- GESTiox IX Dental Practice/' before long.) TRANSFER THE NO=BITE TO ARTICULATOR. Xow let us transfer our test-bite onto the articulator. We '11 use a model of the natural lower teeth: preferably a metal one. Such can be made of low=fusing metal, in a modelings compound impression, as readily as of plaster. And the advantage is that the teeth on it won't wear by careless friction like on a ])laster one. The shallow sockets, aforesaid, in ovu* upper bite^rim will be our guide in placing the bite onto the lower model. If we have no face5bo^^^ or don't know how to use one. or can't find the exact condvle 206 Greexe Brothers' Clinical Course movement, we '11 substitute our always avail- able three=andsashalf=inch measurement * stick. But if we use the old "plane^line" articulator there 's no danger of getting a bite too far back in its jaws. We '11 then first place the lower model cor- rectly straight in the articulator on the table with the ends of the teeth at least approxi- mately three and a half inches from the cross- bar, and fasten it there. Then press the bite to place onto this lower model carefully; then the upper model into this, its bite=plate. Then bear down firmly on the model, without press- ure on the metal jaw, while we plaster it all together. We '11 next change off our bite^plate for a base=plate, onto which the teeth will set. This basesplate, as shown in the double*set case, should be of the Kerr "Perfection," and pressed onto the model as I have before shown. Of course, all base^plates must be secured onto their models before placed into the articu- lator; and absolutely held so during the sticking of teeth there=on=to. This is done with not less than three little patches of hot modeling com- pound of ^4 ^^^^^ width. Next, we '11 set the teeth to the lower model always w ith an eye on the set^screw. AVe '11 jirst give tliem a square "one=way" come-together, and then follow up with the chewing movements of tlie articvdator lower jaw. And here is the advantage of metal models of the lower teeth over ])laster ones: the metal ones won't wear off by the adjusting, frictional, chewing process, in anatomical adjustment. IN Dental Prosthesis. 207 From this on, the work is the same as sho^^'n in the upper one of our double set. PINK RUBBER AND GUM SECTIONS. To be honest with my patient, I \\ould use pink rubber, if at all, no higher up than the laugh=test indicates. When I want to make an extra nice set of teeth on vulcanite, I use gum sections of pat- tern and shade to harmonize with my patient's normal face and her age. I think harmony may be of even first im- portance, over tlie fit of artificial teeth. For a plate worn in a hand-bag won't do botJi, dis- grace the dentist and disfigure his patient. I well remember when it was unethical and disgraceful to make a permanent denture of "plain teeth." In fact, gumless teeth have made rubber work so easy, in a manner, as to bring it into disrepute. BITES IN SCATTERING CASES. On my rounds among dentists I find quite a good many still taking base^plate rim^bites in ])artial cases of scattering teeth. In such a case, the best and only bite needed is to make models of the natural teeth, upper and lower, and i)lace these together ])roperly on the artic- ulator, and exactly as those touched in the mouth. Abrasion of the natural teeth, co])ied onto tlie models, will nearly always sliow how to match the models in the articulator without any other bite. But, in exceptional instances. thin sheets of bite=marked wax will hel)) in the adjustment. Indeed, in many cases, it 's not necessary to even put them in the articulator. Well, indeed, I 've met several fairlv successful 208 Greene Brothers' Clinical Course plate* workers (from the old* way view poiiit) who never use articulators in any case. PRESSOMETER IN UPPER CASES. In single upper cases, it is seldom necessary to use the pressometer; only when decided dif- ference in texture at different places is evident. You have been shown its practical use under such circumstances. But, in any case, the teeth on the wax base= plate should touch their opponents a little bit first over the soft parts, to make up for un- equal settling. The exception is where hard parts support adjacent soft ones. From this on to the finish of our single up- per case, we '11 closely follow the demonstra- tion, directions, and precautions given in the upper one of the double set. We '11 sacredly lieed the points of special importance in ma- terial, flasking, packing, vulcanizing, and the countersign: Keep an eye on the set'sereic, and don't spring the articulator. PARTIAL POSTERIOR LOWER BITE. Here is a case of a partial lower set, where, for instance, the molars, and maybe biscupids, are lacking; but the front teetli are intact. It is a case; wherein even truthful dentists will sometimes — ^prevaricate, a little. At least, I think so when they tell me tliey seldom have to grind the teeth off after vulcanizing. Only those who carefully observe and get the proper strain in taking their bite, or in trying the teeth in, can truthfully avoid making the common error of getting the jaw teeth too long — if the tissues under the plate are soft. And it comes about in this way: They take the bite too hard; that is, the material is too IX Dextal Prosthesis. 209 hard, or tlie pressure on tlie soft tissues too strong — maybe both. The prineiple is iUustrated in the use of our pressometer. (Index P.) A short way of stating- the fact is this: The patient bit more into the flesh than into the ma- terial. In the biting, the natural teeth didn't give down at all. If the soft tissues under the bite- plate gave ant/, then the finished teeth, when set up to tlie bite, will, of course, come together just as much too soon as was the difference in the yielding. xVlso. at the natural wearing stress of a dent- ure, of course such gums yield some. Now, whatever amount they are forced to give more than this, by undue strain in taking the bite, represents the amount the teeth will have to be shortened. And since most dentists (nearly all) take such impressions, abnormally straining for such tissues, just so many have to after-grind; or else compel their patients to go through an un- necessary, long season of annoying and painful adjustment. And, of course, just the same results follow undue pressure in trying the teeth, set up on tlie base^plate, in the mouth. "Just wear 'em till you get used to 'em," But it is reversely true that, in such cases of soft tissues, insufficient strain on the bite gives lack of proper up-touch of the teeth. So it sometimes ha])])ens tliat, in cases of too light pressure in tlie bite, tlie artificial teeth are cor- respondingly too short. While we can get the ])ressure almost ex- actly right, with little trouble, by the use of the pi-essometer test^slips in clear mouths, we can get it practically so without them in ])artial cases by my recent compensating discovery. 210 Greene Brothebs' Clinical Course And this is the way 1 do it: I first make my bite=plate, preferably of Kerr perfection base= plate material, to tit snugly onto my model. Then stiffen it with annealed brass wire. The soft wire is first bent to the bare model and then warmed and pressed into the now^placed base^plate. Though this wire is pliable, it is stiff enough to make the base - plate rigid, so it can he removed, off and on, in the preparation and oper- ation. On this Kerr base I place modeling com- pound to reach up to the opposing teeth, natural or artificial, above, and to press them a little; then trim off the sides of this bite^rim to rid of surplus. Then for the bite. The compound, alone, is warmed and the jaws closed on it till the front teeth come properly together. Their coming- together is our guide=stop. xYotc, if the bite-rim is softer than the flesh under it, the pressure will not be too strong. But the chances are five=to=one that the material will be too hard at the actual biting instant. As I rather expect this, I forestall it with a very thin, soft plaster addition on top of the compound, after first shaving off a little of the latter, to make room for the plaster. The slow setting of the creamy plaster gives ample time for the operation. And tlie softness of it always provides against overstrain. But in very soft cases, where the gums are sure to settle a good deal from pressure by wear- ing a plate, provision must be made for the change. That is, the artificial teeth, when fin- ished, should touch their opponents a little before the front natural ones touch theirs; the amount IX Dextal Prosthesis. 211 of the CiVtra strain being" according to the softness of the tissues. 1 arrange for this fore-touching of the arti- ficial teeth by placing a sheet, or several sheets, of tinsfoil on the ends of the front lower natural teeth, closely adapted, ichile the bite is taken; and then place it onto the model when the arti- ficial teeth are being set up. The thickness of this provisionary foibstrip depends on the yieldance of the gums to be bitten on. It gives to the rear artificial teeth an extra length just a small per cent less than the thick- ness of the foil. The grain of guess=work about the foil provision is made admissible by the accommodating adaptability of soft tissue. Any- how, it is practicable enough to bridge over a deep chasm of trouble. (This simple, new solu- tion of a vexing old problem is carefully shown in our verbal Course.) X. B. — I should have stated timely that I re- move at least a part of tlie modeling'compound* and=plaster=bite from the base-plate foundation, after the case is in the articulator; and then put enough sticky=wax on to set the teeth into. The base-plate itself isn't removed until tlie flask is opened for packing. It may not be amiss here to re-mention that in these partial cases the lateral movement of the jaw should be attended to, either on tlie bite- rim in the mouth or on the articulator. The latter is preferred when tlie bite on the modeling compound is finished out with the cream=like plaster. Sometimes both are advisable. In fact, such cases indicate our scheme: Kach mouth its ozcu articulator in the iiui.sJi — which 1 will now soon show you in gratitudinal detail; and extrem- est satisfaction. I hope. 212 Greene Brothers' Clinical Course You are all familiar with the use of tlie car- bon and wax strip in after^grindint*- for occlu- sion. Well, I 've given you a much preferable way, by which all such grinding is done unknown to tlie patient, and with utmost accuracy; that is, by taking a short=bite, re^articulating the fin- ished plates, and doing all grinding in the lab- oratory, out of sight. But, if only a little touching'up is needed, you can indicate with the Kerr tracing'Sticks. Dry the teeth, trace=on a thin laifcr, warm it well, and have patient bite into it. Then remove the particular thin flake where it is bitten through, and grind ^vith small carborundum bulb. Then trace=on more and repeat, biting and grinding, till you get a close^touching occlusion everywhere. IX Dextal Prosthesis. 213 THE NEW COMMON SENSE OCCLUSION. EVERY MOUTH ITS OWN ARTICULATOR. Since the publication of this Printed Course in 1910, I have made the most valuable discovery in occlusion ever mentioned, and the most prac- tical invention for carrvino- it out after secured. And, of course, this introduction will make obso- lete some of the ways and means that were ad- vanced thoughts a few years ago; in fact, so///£' I ve just given you. I here refer especially to the scientific methods of grinding teeth after tlie plate is vulcanized, to secure technical occlusion. We have no use for these grinding methods any more, for we have a method for securing final occlusion ( "every mouth its own articulator in the finis"), with anatomic perfection, proving it by actual test, and then holding it until the work is finished. For explanation and illustration: — ^^Doctors: — how often it happens that when you have the most perfect occlusion of teeth in dentures hcfore packing, you find you have to grind to correct it after vulcanizing. Kvery plate maker often has this "luck." Faulty occlusion may result from several dif- ferent causes; as incorrect bites and wrong and conflicting pressures in impressions and bites. If you took an impression (in some mouths) at one strain and your bite at a different strain your case would not occlude in the mouth, when '^'try- ing your teeth in." And so would an uneven closing of your fiask give a similar result. All this you know by experience. 214 Greene Brothers' Clinical Course For example: after you set your teeth up ou your base*plates in your articulator you take your case off the model and try it in the mouth. Now, why ? To "see'' whether it is right when in the mouth. That is to say, you can't trust your bite, or your articulator, and now wish to verify by actual test. Well, when your test is satisfactory, are you dead sure you get it back onto the model exactly as it was before ^ Possibly you strained it a little in replacement, if nothing else. If not, well and good. Biit^ what if you find, in another case, that it does not occlude rightly in the mouth? Then, why not? Because you are trying it in at a different strain on the tissues from what the strain was when you took your impression, or when you took your bite. A conflict of stress throws you off. (How few ever think of this!) When 5^ou correct it in the mouth (of course by the anatomical movements of the jaw), now, how are j^ou to maintain this correction when you put it back onto the model for investment in the flask? Do you see your trouble? AVell, now let us take our bite, verify our occlusion and take our impression all at the same strain, and avoid conflict of stresses. It will take a little bit more work and little time, but we '11 save more in the long run. We '11 wind up with just the occlusion we want and avoid all grind- ing after vulcanizing. We will take our case off the model, from the articulator, correct it in the mouth anatomi- cally ("every mouth its own articulator in the finis") and take a final plaster impression in the adjusted and occluded case itself; and produce a model in place and never take the case off of it until after vulcanizing. IN Dental Prosthesis. 215 The work is thus: Adjust the set=up and waxed'up teeth to anatomical occlusion by real anatomical movements of the jaws themselves. I'irst as to the up-and-down motion, and then as to the little natural lateral motion of the jaw that is used in chewing. (Don't over=do this stunt by exaggerated "lines," "])lanes" and "paths" for show purposes. ) Your stiff, hard base=plate sticks fast in the nioutli and you can thus occlude to teeth with ease and perfection. (If necessary, use gum tragacanth to stick it.) Xow, let the ])atient spit the case out of her mouth carefully, for the sticky wax may be a little soft around the teeth. Use a mouth blowpipe and melt the wax fast to the pins in the teeth and cool the whole thing. Xow, fill it with tliin j)laster; pour out all the l)]aster you can; replace a wee^bit in the center (all impressions must scatter from the center) and take her impression, letting patient bite down lightly, and hold it firmly till the remnant in the little jjorcelain imjn-ession bowl is hard; then have her spit it out again. Xow, Doctors, doift here forget to scarify the l)ase*plate a little and wet her mouth with olive oil just before taking the im])ressi()n. Olive oil and glycerine together will ])revcnt adhesion to the tissues. Xow. take the impi-ession out carefully, and after it is dry brush on your separating fluid as usual. Xow "pour" and make your model (much ])referably using the (ireene Approximate metal models). Then, when your model is made leave it in the impression and go on and invest as usual. But, Doctors, listen to me: I am now "oiup' to tell you something of importance; but will first ask you a question: How often, when you have the most satisfactory occlusion /// flic mouth, you 216 Greene Brothers' Clinical Course have to do more or less grinding of teeth in cor- recting occhision after vulcanizing. Every plate maker has this experience be- cause it belongs to and is a part of the old, vm- certain way of doing plate work. Well, if you had perfect occlusion before flasking and now it is "off" what has happened^ AVhy, in bringing the sections of your flask to- gether, after packing, the plaster yielded, gave Avay by compression, and the teeth became mis- placed. They were either pushed outward or pushed down into the disintegrated, soft plaster: or, maybe both. And you vulcanize your plate with teeth in misplaced condition. You brought the front part together first (as often must be done) and in bringing the heels together you used more force; so your jaw teeth were pushed down into the plaster the most. The result is that your once good occlusion now strikes first at the heels in the mouth after vulcanizing. Xow, I have invented and constructed a very simjjle, convenient and cheap method and an appliance for holding teeth in place, ahsolufeUj, so that you have the ])recise occlusion after vul- canizing that you liad before. This new inven- tion we call Greene's OecJusion Retainer. IX Dextal Prosthesis. 217 GREENE'S OCCLUSION RETAINER. This is a metallic re-inforcing appliance to strengthen 2)laster, or other investment, and pre- vent the yielding and displacement of the teeth under flask pressure, during the processes of Masking and vulcanizing. It is a metallic plate of copper sheeting, constructed semi=circle with a perpendicular wall and horizontal floor. It is made adjustahle, to be fitted over the ends of the circle of the set-up and waxednip teeth be- fore douhle=flasking. Thus, after you have your case occluded ("tried"' and corrected in the mouth) and set into the flrst half of the flask and are ready to double^ flask, adjust the retainer over the arc so that each tooth may sit against the floor-angle, or nearly so. This adjustment is done by springing and bending the horse=shoe'shaped appliance with fingers or pliers. When it is adjusted onto the arc of the teeth take it ofl' and fill it with plaster (jolting out all air bubbles) and slip it back onto the ends of teeth, plastered fast. Well, now go on and double=flask as usual. When you open the flask you find the ends of the teeth setting down onto the floor and u]) against the side of the metalhc rehiforcer and held there irresistibly. No matter how much strain you exert in flasking, yoiu- teeth can't yield in the investment. Xow, if you had correct occlusion before, you still have it after vulcaniz- ing. With the proper use of Greene's Occlusion Retainer you never need to grind even a cusp after vulcanizing, if correct before. And, Doctors, you often have your plate to come out much thicker than your base=plate. This may be caused by the compressing of the arch of your ])laster investment, under heat moisture and ])ressure. To reinforce this T have 218 Greene Brothers' Clinical Course invented a metallic arch to be placed onto the palatal part of the base=plate before double* flasking. By the use of this little device plates come out the same thickness of the base plates; so no scraping is needed; none allowed in Greene's system. Scraping on one side of a vul- canite plate, and not the other, causes weakness and liability to warp and break. FULL DOUBLE SET. In case of full sets (two dentures) you go on and do just as I have told you up to the point of taking the plaster impression ("pass=word method") . In case of double sets 3'ou needn't use the plaster in the upper set. We don't use the plaster to improve the fit of the plate, but to maintain the occlusion. When you make both plates just go on and vulcanize the upper (jn the original model, after verifying occlusion in the mouth. When finished then re-test the lower to it. Then take plaster impression in the lower, biting it up against the finished upper set, just as I have described the taking of it for a lone upper case. I will repeat: the taking of the plaster im- pression in the case is not to improve the fit of the plate to the mouth ; that has been guaranteed b}' your first advance "test" impression. But it is to secure occlusion at proper strain, and main- tain it against change, to the finish. However, if you finish the two plates together then better use the plaster in both sets, as described. But it 's best to occlude the lower teeth in wax to those in the vulcanized plate above. The plaster in the lower case will furnish a model in its exact, right relation; and the Occlu- sion Retainer will hold every tooth into its place in its investment while packing and vulcanizng. IN Dental Prosthesis. 219 COMMON SENSE OCCLUSION SHOWN IN MOUTH. Class asks that I review this and show it in my own mouth. 1 'm glad to do it; as it 's my last "discovery" and best stunt in the 'whole bite and occlusion business. Well, I '11 begin anew and take, for instance, a "test" modeling compound impression (Kerr- Perfection) as shown in our first lecture lesson. (Could take it in plaster by the pass-word meth- od, but no need of it.) But, now, 1 11 first take a modeling com- pound impression of my lower natural teeth and pour a model, to l)e hardening while I take my upper impression. Xext I '11 take my upper and make a plaster model on it. And on tliis plaster model I '11 make me a Kerr Perfection base=plate, as I 've already described. ^lake it fit. Xow I '11 take my close=range no*bite as you have already been shown. And to hurry up matters I '11 take my no^bite in Greene sticky wax, well fastened onto my basc'plate. And I '11 not forget to strengthen my base^plate across at its rear with a little wire heated onto it. I '11 now articulate my case here in my ana- tomically im])roved Old'Line "approximator." It has all the movement I need, since its regener- ation. This A\ill give me as close occlusion as ever secured in any old way. But, see here, doctors, I may have, in my semi^soft mouth, taken my impression and my bite'])ressure and my mouth-itself occlusion at varying stresses. I '11 do away with all con- flicting strain and take 'em all at the same exact strain, all at one time, in a new plaster impression. I '11 take the case off of the model, in the ar- ticulator; put it into my mouth and anatomically 220 Greene Brothers' Clinical Course readjust the upper teeth to my lower natural ones. While the case, waxed^u]), will, as a whole be cool and rigid, the teeth thereon, themselves, will be slightly warmer so as to give a little in their wax environment. I '11 slip the case into my mouth and bring my jaws together by a no*bite. I '11 finger*pull the teetli down onto my natural lower ones all round till they all touch the way I want them, while at the same time I '11 bite up lightly. Xow all are together, perpendicularly. I '11 hold them so and "side=wiggle" and sheep=chew ( lateral motion ) , a little. Xext I '11 spit the case out of my mouth and most carefully mouthsblow=pipe tlie sticky wax to the pins of the teeth. This is natural anatom- ical occlusion. Xext I '11 cool it all and scarify the roof of my base*plate a little. And I '11 olive=oil my mouth a little; and take a thin plaster impression (pass-word way), in my adjusted case. I '11 wait till the remnant plaster in my little earthen bowl is hard; and then spit it out again. I '11 be careful not to touch the waxed teeth, for fear I might displace them. Xow, after my plaster impression is dry, I '11 varnish with separating fluid; then soap*stones dust it with soft brush and therein make my final model; of course, this time preferably using the Greene ready-made approximate. Xow, doctors, you see I 've taken my impres- sion in my bite and my occlusion pressures at all same stress; all at once. So there can be no con- flict in them. Xow I '11 set my case in the first half of the flask, seeing there is but little, if any, plaster under it, to disintegrate and change. And here IN Dental Prosthesis. 221 I '11 adjust Greene's Occlusion Retainer over the ends of the teetli and plaster it on iclthout hluhhers; and go on and finish double=flasking, as usual. And I '11 go on and pack, and vulcan- ize at lowest temperature and cool off slowly. The metal model will prevent any change in my plate. The Occlusion Retainer will prevent any displacement and change in the teeth in their embedment. And by vulcanizing at low temperature and cooling off slowly, I '11 not have to grindstouch even a cusp after vulcanizing; not once in a hun- dred times. Xor in fact did I grhid any in occlud- ing. I have the smooth, sharp, definite cusps as made and l)urned onto my grinders. And I need them since my lower teeth are flatly abraded down from 75 years grateful servitude. Well, now, doctors, if I' ve used the Greene= Roof Re=enforcer to ])revent my vulcanite plate from coming out thicker than my base-plate (Kerr's is the ])roper thickness) I '11 have no aftersscra])ing to do. Xo filing, no grinding, no scraping by the Greene system of platenvork. CORRESPONDENCE SOLICITED FOR GREENE BROTHERS' VERBAL COURSE TO STATE MEETINGS, DISTRICT MEETINGS. STUDY CLUBS, COLLEGES and CLASSES Address: DR. J. W. GREENE Chillicothe, Mo. KERR PERFECTION IMPRESSION COMPOUND Test impression taken by Dr. J. W. Greene of his own mouth in Kerr Perfection Impression Compound, showing complete muscle trimming. A plate from it would be a minute duplicate without any further trimming. KERR PERFECTION IMPRESSION COMPOUND Softens Easily — Hardens Quickly It is Impossible to Make Good Work With a Poor Impression. Kerr Perfection Lmpression Comtouxd takes a clean cut, sharp impression, showing e\ery detail with accuracy. Softens at a low temperature. It hardens quickly and evenly in the mouth, becoming very hard, and does not warp or creep. A perfectly fitting plate can be made from a Perfection Impres- sion where other means have failed. (Dr. J. ^^^ Greene has used this material exclusively in all his clinic impression-work). PRICE, per box, 38 CENTS Manufactured by the Detroit Dental Manufacturing Company DETROIT, MICH., U. S. A. Kerr Perfection Compound Sticks . Are very convenient when it is necessary to add a small quantity of material to an impression. The end of a stick can be softened or meUcd over a Hame and quickly and accurately traced on where wanted. (Suggested hy Dr. J. W. Greene.) PRICE, per box. 38 CENTS Manufactured by the Detroit Dental Manufacturing^ Company Detroit, Mich., U. S. A. Kerr Perfection Impression Compound Wafers Are thin sheets almiM nc i . .i;. ~ ..f light cardboard. Can be softened quickly over a llanie and spread over a surface to add slightly to its thickness. Will be found very convenient for a temporary refit of the roof and ridge of a plate. (Suggested by Dr. J. W. Greene, for various uses.) PRICE, per box. 38 CENTS Manufactured by the Detroit Dental Manufacturing Company Detroit, Mich., U. S. A. KERR PERFECTION BASE PLATES For Trial Plates. A thin, rigid base plate that will not soften or bend with the heat of the mouth, making it invaluable in prosthetic operations. In vulcanite work one base plate will last for all the neces- sary operations, such as taking the bite, setting up the teeth, trying in, etc., etc. Directions. AhhdUgb (lr\ heat may lie used to .soften for adaptation to the model, the best results arc obtained by placing both tlie cast and the base plate in water as hot as the hand will bear and gradually working down to the model. Then trim excess, glaze sharp edges over a burner and cool. Price, per box $ .40 Manufactured b\- Detroit Dental Manufacturing Company Detroit, Mich., U. S. A. Greene Sticky Wax Especially prepared and put up in convenient form for plate work, where a good strong sticky wax is needed for waxing the teeth to the base plate. PRICE, per box, 40 CENTS Manufactured by the Detroit Dental Manufacturing Co* Detroit, Mich., U. S. A. Greene-Kerr Impression and Bite Trays with Removable Handles As Used in Dr. Greene's Test Method of Taking Impressions PATENTED MARCH 14,1911 Nos. 1, 2, 3, 4, Upper Nos. 1, 2, 3, 4, Lower Xos. 5, 6, Lower I'artials These trays are made of a thin flexible metal with lower rim, shorter in length and shallower than the finished plate is to be so that the metal does not strain on the lip and cheek tissues or back palate. They are so shaped that they require a minimum amount of change. The handle can be quickly removed for muscle-trimming and to show how impression fills out the lip and cheeks ; — reinsert handle for removal. 'i'lie trays are specially designed for taking impressions with Kerr Perfection Impression Conii)ound l)y the Greene System. PRICE. each $ .30 PRICE, full set of ten $3.00 Manufactured by the Detroit Dental Manufacturing Company Detroit, Mich., U. S. A. THE GREENE READY-MADE, NON-CHANGEABLE APPROXIMATE MODELS For Vulcaniteand Celluloid Work, and Swaging. Invented by Dr. J. W. Greene. Patented June 13, 1908. Doctor: Doesn't it frequentlj', if not often, happen that with even a "good impression you have a badly fitting "denture" ? Do you know how this mostly happens? You'll probably answer : "My impression changed before I poured my model, or, maybe, my model changed before I used it." These things may have occurred, but nine chances to one they did not. Your trouble far more probably came from change that took place in your plaster model in Hasking and vulcanizing; or in squeezing, if a celluloid case. Why, even the very best of plaster models are liable to change shape under heat, moisture, and pressure. And faulty ones are sure to do it. In fact, most plaster disintegrates at about 300° F. So you nearly always vulcanize on a soft-surfaced model, and often on one really mushy throughout. In such cases you depend on environment to hold your mu.sh in shape. But if your pressure in flasking is heavy, or undue in any direction, your soft plaster model will yield, and your plate will differ in shape from your impression of the mouth. The remedy is THE GREENE READY-MADE NON-CHANGEABLE MODEL SYSTEM. These models are made of cast Aluminum, 100 different shapes in a set — 87 uppers and 13 lowers. The uppers are of seven different sizes, numbered from 14 to 20, these sizes grading one-eighth of an inch in difference in width. Then in each sice there is an average of a dozen dift'erent shapes to conform to as many different styles of mouths and gums — as deep, shallow, thick, thin, broad, narrow, etc. These shapes are lettered. With these 100 full patterns any normal case can be accom- modated. The models cannot break, bend, wear out, nor get out of order; but may be used over and again indefinitely. The full set is put up in a neat case, with a special compart- ment for each shape, numlicred and lettered. HOW TO SELECT, FIT AND USE THEM. Take your impression as usual; or better, by the Greene method, using Kerr Perfection Impression (which gives you the exact Iieight of rim and length of intended plate, and an abso- lute advance test as to its fitting). Now measure across the back of your impression, from outside to outside of tul)erosities, to get its she and immber. For instance: two inclies wide would be the width of No. 16. Select from model No. 15, which is one-eighth of an inch narrower than No. 16, the nearest the shape of the impression. This selected model should slip loosely down into the im- pression. If it lacks a little of go:ng in, use Carbon paper to indicate and find the places, and file or scrape the model off to let it in with, say. an eighth of an inch play; less will do. After your model will drop into the impression readily, it is fitted. Then mix your plaster (good plaster), smear your model all over its face-surface carefully; then pour a little plaster into the impression, fullest in the center, and push the besmeared model down into it, and go on and finish as if model were all plaster. You now liave a model aI)out 90 per cent metal, in bulk, with 10 per cent or less of i)laster veneering over its face. The metal will not change at all, while the very thin coating of plas- ter facing (being supported by metal) cannot change perceptibly. Nor does it take much longer to make this non-changeable cast than the old. faulty, all-plaster sort. Go on and use it the same as if all plaster, in vulcanite or celluloid work. In using these ai)proximate models for partial cases, first fill the tooth sockets in the impression. If in removing the impres- sion from the model you should break off a tooth, just cement it back to its place with thin cement, which makes it stronger than before broken. TO SEPARATE IMPRESSION FROM MODEL. Remove the impression from the model, rather than model from impression. First remove the metal tray from impression, by warming the metal over spirit flame. If impression is model- ing compound (Perfection Impression Material), or wax, first warm the impression gently in shallow water, leaving the model as cool as possible, and peel the former off from the latter. FOR SWAGING. To complete them for swaging, use a half-and-half mixture of Portland cement and plaster, well ground together in a mor- tar, before wetting. And to swage on them w-hen the new process methods of pressure are used, first "cow-horn" your blank plate over a metal model of the next size larger than the one you are going to finally swage to. If you u.se the Greene method of taking impressions, you can swage turn the very utmost rim edge of your plate, to fit the muscles to such exactness as to need no trimming after plate is wi>rn, unless the mouth changes. Price, Full Set of 100 Models, $20.00 Price, Selected Set of 24 Models, 6.00 Manufactured by DETROIT DENTAL MANUFACTURING CO., DETROIT, MICH., U. S. A. GREENE S OCCLUSION RETAINERS t*-£.s-£0 NOV. 4 1613 A flexible xnetaJlic semi-circle, re-inforcing appliance with perpendicular wall and borizontal floor. To be fitted o\er the endi of the set up and waxed up teeth l^rfore double flashing to strengthen plaster or r investment, and pre\-ent the yielding and dis- -, . . .- ♦. , . ..-. ... ^^_ ^"-c^ pressure during the •^• Most valuable in Gum -Section Cases. After ycm have case set into first half of flask and ready to double flask adjust the retainer o\-er the arch ' *""ateach tooth may set against the floor angle or .-.' so. When adjusted to fit arch of teeth, fill it with plaster, jolt otit air bubbles and slip it onto them and finish fla&king as usual . Price Set of T^ree. 7ftc. ■ afiulactpffcC i>j tne Detroit Dental Manufacturing Company Detroit, Mich., U. S. A. /^ COLUMBIA UNIVERSITY LIBRARIES (hsi.stxi RK 656 G83 1914 C.I Greene brothers clinical 2002126281 J