HX00044490 
 
 SOME METHODS AND APPLIANCES 
 
 OPERATIVE AND MECHANICAL 
 DENTISTRY 
 
 ■ 
 
 ■ 
 
 ■ 
 
 ■ 
 
 
 ^h Hi 
 
 I • : 
 
 
 I 
 
 ■ 
 
 ill 
 
 Hi 
 
 I ■'■*f. : £» V -'< 
 
 
 ■HI ■ WKSt 
 ■■Mm SaPs 
 
 WFmt 
 
 H^H »g«^ 
 
TfK65l L54 
 
 Columbia ^ntucrsttp 
 in tfjcCitp of J^etogorfe 
 
 College of $3fjpstcians nnb burgeons 
 
 Reference ILibvavp 
 
 r . 
 
 -«v?< 
 
 Presented By 
 
 DR. WILLIAM J. GIES Jf 
 
 to enrich the library resources 
 
 available to holders 
 
 ofthe 
 
 GIES FELLOWSHIP 
 
 in Biological Chemistry 
 
 'ifl 
 
SOME METHODS AND APPLIANCES 
 
 IN 
 
 OPERATIVE AND MECHANICAL 
 DENTISTRY. 
 
(STambriUgr : 
 
 PRINTED BY J. AND C. F. CLAY, 
 
 AT THE UNIVERSITY l'KESS. 
 
SOME METHODS AND APPLIANCES 
 
 IN 
 
 OPERATIVE AND MECHANICAL 
 DENTISTRY. 
 
 By R. P. LENNOX. 
 
 WITH ILLUSTRATIONS. 
 
 Honfcon : 
 
 CLAUDIUS ASH and SONS, Limited, 
 
 5, 6, 7, 8 and 9, BROAD STREET, GOLDEN SQUARE, W. 
 
 1897. 
 
Digitized by the Internet Archive 
 
 in 2010 with funding from 
 Columbia University Libraries 
 
 http://www.archive.org/details/somemethodsappliOOIenn 
 
PREFACE. 
 
 The primary object of this little book is twofold. On 
 the one hand, an attempt has been made to reply once 
 for all to questions put to the author from time to time with 
 regard to papers he has read before the British Dental 
 Association and its Branches. On the other, it has been 
 sought to render more readily accessible and useful so much 
 of those papers as appears fairly to have stood the test of 
 experience. 
 
 Advantage has also been taken of the opportunity 
 afforded by the carrying out of these purposes to add a 
 few hints on matters not to be found in the text-books, 
 and further to give an account of those of the author's 
 methods of working which differ from the methods generally 
 to be found there. In doing this, the author has been far 
 from wishing to insist upon his own methods as the better. 
 Long use may well have made even difficult and trouble- 
 some operations easy. At the same time, it is felt that 
 methods which arc the outcome of forty years' experience 
 can hardly be without interest for others, and beginners 
 
VI PREFACE. 
 
 will no doubt be glad to have some latitude of choice pre- 
 sented to them. 
 
 If the author has also ventured to add a few criticisms 
 of other methods, it is hoped that this has been done in 
 no spirit of egotism, but simply with a wish to forward the 
 discussion of moot points and to enable readers to arrive 
 at a decision upon them. 
 
 Cambridge, 
 April, 1897. 
 
CONTENTS. 
 
 CHAPTER I. 
 
 PAGE 
 
 Some Methods in Practice ...... 1 
 
 CHAPTER II. 
 
 A few Tools and Instruments ..... 27 
 
 CHAPTER III. 
 
 Some Uses of Fusible Metal ..... 44 
 
 CHAPTER IV. 
 
 Matrices : how to make them and how to apply them 62 
 
 CHAPTER V. 
 
 Crown and Rrid<;ework ...... 72 
 
 APPENDIX. 
 
 Work i N( j Descriptions of Methods . . . 91 
 Index 109 
 
CHAPTER I. 
 
 SOME METHODS IX PRACTICE. 
 
 Under this heading, I propose to give an account of 
 such of my methods of working as differ in any way. al 
 all likely to be of interest to others, from the methods 
 described in the text-books, and to add a few opinions in 
 passing for what they may be worth. 
 
 It will conduce to clearness to take the several opera- 
 tion-, as nearly as may be, in the order in which they present 
 themselves in actual work. 
 
 Taking an impression. Many people insist strongly 
 that in taking an impression the best result- are not to 
 be had except by the use of plaster. But everything de- 
 pends upon the purpose for which the impression is to be 
 used. If for any purpose a model is desired which shall 
 show the soft tissue- absolutely undisplaced, then un- 
 doubtedly plaster affords the best, if not the only, means 
 of obtaining it, and all the annoyance and trouble for patient 
 and operator which attend the use of plaster inu-t be 
 endured. But to attempt to make a plate from such a 
 model would be to court failure. The plate would ride 
 upon the harder parts of the mouth and, displacing the 
 soft tissues on the side under pressure, would cease to touch 
 at all on the other, [fan attempt is made to correct this 
 L. I 
 
2 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 by relieving the pressure on the harder parts of the mouth, 
 then all the soft tissues will be more or less displaced under 
 pressure, and the plate is called upon to fit a surface which 
 the model does not give. 
 
 On the other hand, when an impression is taken with 
 composition, the operation is as little disagreeable to the 
 patient as such an operation can be, the pressure of the 
 composition displaces the soft tissues just as the plate will 
 afterwards displace them, the impression obtained with any 
 good composition is as sharply defined as any plaster im- 
 pression, and the resulting plate sits firmly at all points. 
 
 It may further be pointed out that it is no objection 
 to the use of composition in taking impressions that it does 
 not give the frenum and similar folds of the mucous mem- 
 brane in their normal positions, since it will show their 
 points of attachment quite distinctly, and it is from these no 
 less than from the folds themselves that the plate has to be 
 kept clear. This is, of course, done by well rounding and 
 turning up the edges of the plate away from the folds at 
 all points, an effect secured in the case of a gold-plate by 
 tilling up the parts of the model, where relief is required, 
 with wax, before casting the zinc. 
 
 Again, the time required for composition to set may be 
 made very short as compared with that required for plaster. 
 After packing the composition into the tray in the usual 
 way, I soften the surface by pouring on boiling water from a 
 kettle. This is preferable to warming over a spirit-lamp, 
 because there is less risk of overheating the composition 
 and burning the patient's mouth. Then, just before in- 
 sert ing the tray into the mouth, I cool the outside with 
 a spongeful of cold water. The parts of the composition 
 in contact with the tray are thus partially set and help to 
 force the still soft parts into position, while the time re- 
 quired for the whole to set is much reduced. Finally, when 
 the tray is in position, I spray it with cold water from an 
 8 oz. syringe (Fig. 1) with a nozzle bent at right angles, 
 a basin being held close under the patient's chin to catch 
 the overflow of water. In this way the setting of the 
 
SOME METHODS IN PRACTICE. 
 
 composition, which otherwise takes four or five minutes, 
 is effected in about a minute, and the water, in general, 
 
 (r 5 
 
 Fig. 1. 
 
 proves grateful rather than not to a mouth overheated by 
 a mass of warm composition. Irrigated trays have been 
 devised to effect the purpose thus attained, but the trays 
 are cumbersome, and more difficult to insert than ordinary 
 trays, themselves not seldom difficult enough. 
 
 While on the subject of trays, I may say that I have 
 hardly ever found it necessary to make a special tray, a 
 very little ingenuity sufficing to make the ordinary trays 
 serve every purpose. 
 
 Later on (page 78) is given a description of a tray (Fig. 2) 
 
 Fig. 2. 
 
 1—2 
 
4 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 for taking an impression of the root-faces, and for deter- 
 mining the directions and the depths of the root-canals, of 
 the six anterior teeth. 
 
 Casting a model. An impression having been obtained 
 in one way or another, the next thing is to cast a model, 
 as to which I wish merely to say that I deprecate the use 
 of wires to strengthen the teeth, as they necessarily stand 
 out above the teeth and so prevent the models from being 
 brought into correct occlusion, and they cannot be ground 
 away without risk of damaging the teeth, especially upper 
 bicuspids. 
 
 On the other hand, in cases where, say in a lower, a 
 molar on either side of the model leans forward so that it 
 would be difficult or impossible to remove a properly-fitting 
 composition plate, I drill a hole along the axis of the inclined 
 tooth ; fit a wire into the hole ; remove the wire again ; 
 break the tooth, smartly, short off; cut or file the wire to 
 the exact length of the tooth, and replace the wire in the 
 model. As the wire was fitted to the tooth, the tooth can 
 be replaced and held accurately in position ; and can be 
 removed, when the moment for removing the composition 
 plate arrives. 
 
 Models should be dipped in stearine, and pink wax 
 should be used in making them up for casting, as it can 
 be readily removed, when its purpose has been served. 
 
 Making a gold-plate. Numberless are the devices 
 discussed by the text-books for securing a well-fitting gold- 
 plate. As many as three zinc dies .and three lead counters 
 are recommended, and are, no doubt, often necessary in con- 
 sequence of the methods pursued. 
 
 The first counter is made by pouring lead upon the 
 exposed face of a zinc embedded in sand. The result is that 
 the counter is shallow and offers no guide for the die, which 
 is therefore liable to strike awry, and so to obliterate the 
 details in the counter. Hence the need for two and even 
 for three counters. 
 
SOME METHODS IN PRACTICE. 5 
 
 My plan is to wrap a roll of clay around the only zinc I 
 use (Fig. 3), and dip the latter far enough into the ladle of 
 molten lead to cover the clay. The effect of this (Fig. 4) is 
 to give all that is aimed at in the shallow counter, without 
 
 Fig. 3. 
 
 sacrificing the strength and the guide afforded by a deep 
 counter. 
 
 Accuracy in directing the blows and distributing the 
 force of them is also gained by the use of a Pearsall sand- 
 moulding flask, the advantages of which seem surprisingly 
 long in gaining recognition. When this flask is used in 
 casting a zinc die, a strong cone (Fig. 3) is formed at the 
 back of the die, from which these advantages follow. The 
 plaster model need not be more than one inch deep at the 
 heel, the zinc can be readily grasped in a vice and otherwise 
 readily handled, and it never cracks under the hammer. 
 With this die and a counter made as above described, perfect 
 accuracy in directing the blows is obtained, and the life of 
 the counter is much prolonged, so much so that I find one 
 zinc die, one lead and one tin counter sufficient for all pur- 
 poses. My ladle for the counters is hemispherical, and 1 
 always swage in my hand, the roundness of the outside of 
 
() OPERATIVE AND MECHANICAL DENTISTRY. 
 
 the counter rendering this easy. My hammer weighs 2£ lbs. 
 One result of this method of swaging is that the lead counter 
 is not spread to anything like the same extent as when the 
 swaging is done on a block. 
 
 In preparing a plate for swaging, I do not use a lead 
 pattern, but cut a rough pattern in paper rather larger than 
 
 Fig. 4. 
 
 the required plate, the use of the clay as above described 
 rendering this possible without difficulty. Time and trouble 
 in the preliminary adjustment of the plate are thus saved. 
 
 I may add that I have entirely given up the use of 
 suction chambers and all kindred devices, whether in gold 
 or in vulcanite work; they are at all times harmful, and 
 ultimately, by filling themselves with the soft tissues, become 
 inoperative, the better made the chamber the worse the 
 result. 
 
SOME METHODS IN PRACTICE. 7 
 
 Making a base or trying-in plate for vulcanite 
 work. Three things are essential to a satisfactory trying-in 
 plate. It should be rigid, close-fitting, and quickly made 
 It is unnecessary to discuss here how far any of the many 
 ways described in the text-books for making such plates 
 gives a plate possessing these characteristics. It is enough 
 to say that in my own practice I use modelling composition 
 for lower plates and fusible metal for uppers. The method 
 of making a fusible metal plate will be found on a later 
 page (p. 55). It is very simple, and any one who will try 
 it will be able to satisfy himself in a very few minutes that 
 the plate obtained has all the qualities enumerated above. 
 
 Taking a bite. With such a plate we may proceed to 
 take the bite with confidence and at our leisure, and those 
 who use a wax or gutta-percha plate for the purpose, especi- 
 ally if they make dummy bites, will appreciate what that 
 means. But a dummy bite is another of those things which 
 I have not yet learnt to use. It seems that it requires 
 much carving and shaping to give a really good result, and 
 after all it affords no indication of what the teeth will look 
 like ultimately. My plan is to set up temporarily, on a 
 composition plate, all the teeth in the lower jaw ; and, on a 
 fusible metal plate, the six anterior teeth in the upper jaw. 
 In the remaining spaces I adjust blocks of soft wax, and 
 proceed to take the bite. As the metal plate keeps up 
 even better than a finished plate, and the teeth are readily 
 readjusted on it, if need be — though in general careful 
 observation of what is wanted is sufficient — the work of 
 obtaining a bite in this way is attended with as little trouble 
 and difficulty as possible, and the marks made by the bi- 
 cuspids and molars of the lower jaw in the soft wax blocks 
 of the upper suffice to determine the articulation when the 
 plates are removed from the mouth. It seems clear that on 
 this plan, in which the actual teeth to be ultimately used 
 may be employed, we have a readier means of determining 
 what sort of teeth and what setting of them will be suitable 
 in any given case than any mere dummy bite can afford. 
 
8 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 Articulators. There is, perhaps, hardly any other 
 article in the dental workshop over which so much ingenuity 
 has been expended with so little attendant advantage as 
 over articulators. What inventors have aimed at in many 
 of their elaborate devices it would be hard to say. No 
 articulator, be its capabilities as regards movement what 
 they may, can make up for an incorrect bite. If, however, it 
 were possible for any articulator to simulate, even approxi- 
 mately, the movements of each individual jaw that presents 
 itself for treatment, some advantage would, no doubt, be 
 gained by the possibility of seeing that the cusps of the teeth 
 when set up moved over each other in the act of mastication 
 in a way suited to the particular jaw in hand, but it is 
 impossible to attain such movements in an articulator, and 
 the value of any other movements is insignificant. We 
 must resign ourselves to the necessity of testing the suita- 
 bility of any given setting of the teeth by actual trial in the 
 mouth for which they are intended. But if the advantages 
 of these complicated devices are hard to find, their dis- 
 advantages are obvious, for they are cumbersome to handle, 
 both models having to be handled together throughout the 
 working, and they do not afford an unobstructed view of the 
 interior of the mouth. 
 
 The essentials of a good articulator, at any rate such as 
 are readily obtainable, are general ease of handling, accuracy 
 and ease in the return of the models to proper occlusion 
 after handling, and a ready view of the inner cusps of the 
 teeth. All these are in my judgment most readily attained 
 by means of the simple slab bite with an orifice through it 
 for viewing the interior of the mouth. For this reason 
 I always found the old plaster slab a very effective articu- 
 lator, but a fusible metal slab has advantages over even 
 a plaster slab, and these together with the method of making 
 a fusible metal slab will be found described on page 57. 
 
 Setting up teeth. There is but one point in connec- 
 tion with setting up teeth to which I wish to refer, and 
 that is the not uncommon fault of unduly contracting the 
 
SOME METHODS IN PRACTICE. 9 
 
 arch of the teeth of the upper jaw. This contraction is 
 sometimes advocated in order to make room for springs 
 when these cannot be dispensed with, but more generally it 
 a]i] tears to be due to an idea that it is absolutely essential to 
 place the teeth upon what remains of the alveolar ridge. 
 In my view neither of these reasons can be justified, and I 
 make it my practice to keep the arch as wide as possible. 
 
 Springs. In the majority of cases, well-made plates 
 need no special contrivance to keep them in position. 
 Where any contrivance at all is necessary, I prefer to use 
 springs. These are, in general, only necessary where a 
 lower is difficult to keep in position, and even in such cases 
 the use of them may sometimes be avoided by weighting 
 the lower with Watt's or other metal. On the other hand, 
 it sometimes happens that, in the case of very aged patients, 
 the alveolar border is so far absorbed that even springs do 
 not avail to keep the lower in place, and some additional 
 contrivance becomes necessary. 
 
 When springs are to be inserted, a question arises upon 
 which authorities appear to differ, viz. as to the position of 
 the bolts. If these are placed too far back, the springs 
 must either be too short, or themselves go back too far and 
 gall the mucous membrane. My rule is never to place the 
 bolts in the lower further back than just below the centre of 
 the second bicuspid, while in general I place them more 
 forward, the room in the mouth, of course, determining the 
 position in any given case. The bolts in the upper should 
 go vertically over those in the lower, or rather just the 
 least bit backward of that position. 
 
 Whenever possible, I avoid vulcanising the bolts theni- 
 selves into the positions intended for them, replacing them 
 temporarily by pieces of knitting-needle (Fig. 7) taken back 
 to a blue. These are afterwards readily withdrawn by 
 heating the ends with a blow-pipe and using a strong pair of 
 pliers. They are then replaced by the bolts, which should 
 fit tightly into the holes prepared for them. The advantage 
 of this method is that, when the swivels are worn out, the 
 
10 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 bolts can be easily removed and the swivels renewed. 
 Figure 7 shows a piece of knitting-needle applied in a 
 partial case where, of course, it would not be wanted, but 
 this was done to save time and labour at a moment when 
 either could ill be spared. 
 
 To support the spring and keep it from injuring the 
 mucous membrane, the text-books recommend a ledge of 
 vulcanite on the lower set ; some appear to recommend one 
 also on the upper. The ledge on the upper is, in my opinion, 
 worse than superfluous. In the lower to effect the same 
 purpose as the vulcanite rest and avoid friction on the 
 spring, I drill, whenever possible, a small hole just under the 
 stem of the swivel, close to the eye, and insert a piece of 
 tapped wire. 
 
 In cases where, owing to the absorption of the alveolar 
 process, some contrivance in addition to springs is necessary, 
 the simple one shown in Fig. 5 has been proved effective by 
 a patient, now (1897) 96 years of age, who has worn a set, so 
 equipped, with comfort for seven years. This patient had 
 worn a set of teeth with springs for about twenty years, 
 when, owing to the absorption of the alveolar process and to 
 other changes due to advanced age, the lower plate used to 
 slip forward, and was only retained in the mouth by the 
 pressure of the lower lip, which was thus made to protrude. 
 In the first instance, it was hoped that a remedy would be 
 found by simply making a new set on the same plan as 
 before, but adapted to the new form of the mouth. This 
 proving of no avail, a suction upper and a lower weighted with 
 Watt's metal were tried. These the patient said she got on 
 well with ' so long as she sat bolt upright.' In other posi- 
 tions, the lower slipped forward as before, and she had the 
 additional discomfort of feeling the upper drop a little. In 
 these circumstances, the device shown in Fig. 5 was adopted 
 with the result already described, both the slipping forward 
 of the lower and the dropping of the upper being got rid of. 
 It was at first feared that new difficulties might have been 
 introduced in the mastication of food and the clearing of it 
 from the additional mechanism, but no such trouble has 
 
SOME METHODS IN PRACTICE. 
 
 11 
 
 arisen. The contrivance, perhaps, hardly calls for any 
 description beyond what Figure 5 affords. The second 
 
 Fig. 
 
 molars being omitted from both plates, a post with its foot 
 as far back as possible on the lower plate leans forward and 
 carries at the top a loop or ring which just clears the upper 
 plate when the mouth is closed. A post, fixed upright 
 in the upper and just long enough to clear the lower plate 
 in the closed position of the mouth, is so placed as to pass 
 through the loop on the top of the lower post and to press 
 against the loop upon any attempt of the lower to slip 
 forward. A bend at the lower end of the upper post serves 
 to prevent this post from drawing clear of the loop, if at any 
 time the mouth should chance to be opened to an unusual 
 extent. 
 
 This device enabled me to get over what threatened to be 
 a very troublesome case. 
 
12 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 Flasking. When we come to flasking, the first question 
 that arises is : — Shall the original model be used to vul- 
 canise upon and so be lost ? Most people, it appears, would 
 answer ' Yes,' while my practice is — in all edentulous cases 
 and in most lowers — to save the model. It is useful after- 
 wards in testing for and correcting the results of contraction, 
 and in perfecting the articulation, without that repeated 
 reference to the mouth which I make it a principle of 
 practice to avoid. Even in the case of tube-teeth, which 
 have been carefully adjusted one by one in the articulator, 
 a few final touches are necessary to make the articulation 
 perfect after the teeth have been cemented on, and they 
 are not less necessary in vulcanite cases. Therefore, when- 
 ever possible, I save the model. It may even come in later 
 still in the event of accident to the plate. But, if it be 
 decided to keep the original model, a second model to 
 vulcanise upon must be provided. 
 
 Fortunately, with a rigid and close-fitting base-plate 
 such as fusible metal affords, this can be done without 
 difficulty, since a second model quite as good for its purpose 
 as the first can be cast into the base-plate. 
 
 The method of proceeding is as follows : — Let us suppose 
 in the first instance that we are dealing with an edentulous 
 case. The case being ready for flasking, I fill in the spaces 
 between the teeth and any other hollows or recesses, such 
 as the palate, in which air would be likely to be imprisoned, 
 with plaster applied with the point of a knife ; and then 
 invest the plate, teeth downwards, in the deeper part of 
 the flask previously filled with plaster. The plate being 
 embedded up to its edge, the plaster between the edge of 
 the plate and the flask is trimmed level and, when set, is 
 lightly brushed with vaseline, the plate itself being treated 
 in the same way and afterwards wiped as nearly clean as 
 possible. More plaster is now put in, a little at a time, 
 and carefully shaken down by a few smart raps upon the 
 bench, so that no air spaces may be left. The other part of 
 the flask is filled with plaster, and the flask, being closed, is 
 laid aside with a weight upon it for the plaster to set. 
 
SOME METHODS IN PRACTICE. 13 
 
 When this has taken place, the flask is heated over a 
 Fletcher's burner (Fig. 6) and the two parts are separated. 
 
 Fig. 6. 
 
 The shallower part now contains the second model at which 
 we have been aiming. I should add that I prefer to 
 separate the parts of the flask by heating over a Fletcher's 
 burner rather than by boiling, because in this way no water 
 gets at the second model. 
 
 The wax is next carefully picked and scalded out of 
 the deeper part of the flask, and the plate is removed from 
 the model. If of fusible metal, it is divided, for ease of 
 removal, into two or more parts by means of a warm iron 
 rod. and the case is ready for packing. 
 
 If the case is a partial one, some simple devices are 
 necessary to keep the plaster from invading the plate be- 
 tween the artificial teeth, in the process of investing, and to 
 prevent bands and wires from being disturbed, in the process 
 of packing. 
 
 To keep the plaster away from the impressions of the 
 necks of the natural teeth, as soon as the plate is ready 
 for investing and is finally removed from the first model, 
 I attach thin laminae of wax to the lingual surface of the 
 plate, just at the edge, so as to project over the spaces 
 between the artificial teeth (Fig. 7). When the case is 
 invested, the plaster partially overflows these laminae, but 
 docs not reach the impressions of the necks of the natural 
 teeth, and is readily cut away without damage to those 
 impressions. Of course these laminae are reproduced in 
 vulcanite, but, being very thin, they are readily removed, 
 
14, 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 and add little to the trouble of cutting up. If a natural 
 tooth is to be banded, no lamina is placed over the corre- 
 
 Fig. 7. 
 
 sponding space in the plate, because the plaster by flowing 
 into the band secures it in position and prevents it from 
 being disturbed in the process of packing. 
 
 If in a bar-lower a wire strength ener is to be inserted, I 
 take a piece of wire some half-inch or more longer than 
 the strengthener required, and bend the excess at either 
 end at right angles, so that the ends of the wire may project 
 into the mouth (Fig. 7) and be caught in the plaster, when 
 invested, thus securing the strengthener in position during 
 the packing. 
 
 When a tooth, say a canine, is to be wired rather than 
 banded, I secure the wire in position in the flask by making 
 it long enough, after going round the tooth, to be bent 
 up and rise above the cutting edge of the tooth, with a 
 slight hook at the end (Fig. 7). In the process of investing, 
 this hook is caught in the plaster, and the wire is secured 
 against disturbance. 
 
 Lastly, to prevent contraction in a lower plate, I cut a 
 piece of match-stalk to a suitable length and wax it in 
 between the heels of the plate (Fig. 7) before investing it. 
 
SOME METHODS IN PRACTICE. 
 
 15 
 
 This acts as a stay-bar, effectually preventing the contrac- 
 tion of the plate in the cold soft plaster, and it is easily re- 
 moved when the case has cooled after vulcanising. 
 
 Brunton Two-Part Contour Flask. In partial cases 
 where it may be necessary to vulcanise on the original 
 model, as in cases where the teeth are ground to the model 
 so as to appear eventually to grow out of the gum, I know 
 of no flask which offers the same advantages as the Brunton 
 Two-Part Contour Flask (Fig. 8). The illustration shows it 
 
 Fig. 8. 
 
 supported by a special arrangement over a Fletcher's Burner. 
 The body of this flask is so shaped as to overhang the 
 crowns or cutting-edges of the teeth, and this makes it 
 impossible for the teeth to lift from the model in the process 
 of packing, as the flask prevents the plaster from breaking. 
 
 Adding a tooth or teeth to a vulcanite case with- 
 out casting a model. The method of flasking above 
 described, whereby the original model is saved, also enables 
 a model to be dispensed with altogether in the particular 
 case where a tooth or teeth are to be added to a vulcanite 
 ease. 
 
1G OPERATIVE AND MECHANICAL DENTISTRY. 
 
 A dove-tail having been prepared in the usual way and 
 some melted wax having been dropped on to the edges and 
 flowed over the neighbouring parts of the vulcanite, the 
 dove-tail is filled with wax and, the case being placed in the 
 mouth, the wax is carefully modelled to the gum. The case 
 is then carefully removed from the mouth, the teeth are 
 waxed into position, the case is once again tried in the 
 mouth, and is then finally invested in the flask in the 
 manner before described (p. 1 2). 
 
 Packing. Teeth, bands, and wires being all securely 
 invested by the above means in the deeper part of the flask, 
 I proceed to pack into that part. Before doing so, I warm 
 that part by placing it over a Fletcher's burner. Meanwhile 
 the model in the other part is lightly rubbed all over with a 
 soft rag to improve its surface, which is then lightly covered 
 with French chalk, a brush being applied to the more 
 corrugated parts. Then, working quickly so that the deeper 
 part of the flask may remain warm while the part containing 
 the model is cool, from time to time during the packing 
 I bring the two parts quickly together in a press or vice and 
 as quickly separate them, the rag usually placed between 
 them being dispensed with. Owing to the difference in the 
 temperatures of the parts and the quickness with which they 
 are brought together and separated, there is no adhesion of 
 the rubber to the model, and I am able in this way to see 
 w r here there is any excess or deficiency in the rubber and to 
 make it good, with great readiness and without any of the 
 boiling out which some find necessary after every closing of 
 the flask. The progress of the packing being thus readily 
 inspected, I am able to avoid excess of rubber and conse- 
 quently need no gateways for its escape. 
 
 Vulcanising. With a Gartell's gauge to regulate the 
 supply of gas and a clock to turn it off at the fitting moment, 
 the anxiety which Used to attend the process of vulcanising 
 has vanished. One consequence has been that I have some- 
 times been tempted to start vulcanising a case just before 
 
SOME METHODS IN PRACTICE. 17 
 
 leaving work for the night,, but I have found unfortunately 
 that a case left to cool all night in the vulcaniser is much 
 more difficult to clear of plaster than one attacked as soon as 
 it is possible to handle it. Hydrochloric acid and water 
 will indeed help to remove the plaster, but I should not 
 recommend anyone, who is expecting to see a patient, to 
 try it. 
 
 A hint which I gained very opportunely some years 
 ago, from Mr W. Fawssett of Cambridge, with regard to 
 vulcanising on a gold base may be given here, on the 
 chance that it will be as useful to some as it was to me. It 
 is that the tendency which the vulcanite has to curl slightly 
 away from the gold plate may be overcome by carefully 
 polishing, and rouging, and keeping free from grease, that 
 part of the plate with which the vulcanite will come in 
 contact. 
 
 With regard to the position of the flask in the vulcaniser, 
 I have an idea that the teeth are less likely to change their 
 positions in relation to the plate, if the deeper part of the 
 flask is placed downwards in the vulcaniser. 
 
 Lastly, as to the vulcaniser itself, I would add that a lead 
 washer, which is easily prepared from a piece of lead wire, 
 will last for years, if only due care be taken, in screwing up 
 the vulcaniser, always to bring together the same two points 
 which have once been found suitable. 
 
 Tube-teeth on a vulcanite base. By way of transi- 
 tion from vulcanite work to gold work, I may here explain a 
 method I sometimes adopt of using tube-teeth with a 
 vulcanite base. A fusible metal plate being prepared as 
 before (p. 55), I fix it on the model with wax ; fill up with 
 wax any inequalities in the ridge, so that the teeth required 
 may be all of one length ; and cast a model in zinc. With 
 this zinc a gold strip of a width just sufficient to carry the 
 teeth is struck up to fit the ridge. To this plate tube-teeth 
 are fitted in the ordinary way, and, the teeth being in posi- 
 tion on the pins, the case is so waxed up that, when it is 
 vulcanised, the gold plate is covered by the vulcanite, but 
 l. 2 
 
18 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 the teeth will with a little humouring readily leave the 
 pius. 
 
 This method of making uppers allows of a ready renewal 
 of the plate in cases where the mouth alters through the 
 absorption of the alveolar process and well repays the extra 
 trouble expended at the outset. The teeth have an individu- 
 ality which they lack in an entirely vulcanite set, and may 
 have all the interstices of natural teeth. They are also 
 stronger than vulcanite teeth, especially in the molar region, 
 while, should a tooth be fractured now and again, it can be 
 replaced without the repeated vulcanising which is so 
 destructive to a vulcanite plate. Moreover, when a new 
 base is required, the teeth being already set up and correctly 
 articulated, the labour of adapting a new base to them is 
 small. 
 
 Shallow Bites. Sometimes a bite is so exceptionally 
 close that, instead of using porcelain teeth for the molars, 
 whether in gold plate or in vulcanite work, it is advantageous 
 to use shallow gold crowns. In such a case a very natural 
 and effective masticating surface is obtained by striking up 
 these crowns with dies made of natural teeth 
 (Fig. 9) and used as described on p. 50. 
 
 Ash's Mineral Teeth. The following 
 notes on Ash's mineral teeth were put together 
 some time ago in reply to questions from the 
 Firm. As others have from time to time asked 
 Fig. 9. me similar questions, the notes may perhaps 
 
 be usefully given here. 
 Although Ash's mineral teeth have now been before the 
 profession for close upon sixty years, and many references are 
 made in dental literature to the fact that they are of the 
 same non-porous texture throughout and can therefore be 
 ground and polished to any extent that may be desired to 
 suit special cases, it is yet remarkable that no writer has 
 attempted to give definite instructions for grinding and 
 polishing them. 
 
 By way of introduction to making such an attempt, I may 
 
SOME METHODS IX PRACTICE. 19 
 
 say in the first place that the density of these teeth permits 
 of their being ground to a very fine edge without the risk of 
 chipping, and, if necessary, the ground surfaces can after- 
 wards be highly polished. A further advantage is the absence 
 of the particles of porcelain which in some teeth are found 
 encroaching upon the pins, as the removal of these particles 
 in the process of backing teeth involves both annoyance and 
 loss of time. 
 
 To grind the teeth. For this purpose I use carborun- 
 dum or corundum wheels running in a trough of water when 
 doing work with the lathe, and carborundum or corundum 
 wheels and points when doing it with the dental engine. 
 
 The use of carborundum pretty well does away with the 
 need for a steel tool in countersinking, but, where a dental 
 engine is not at hand, the teeth may be countersunk by means 
 of a graver and camphorated turpentine into which the 
 graver is dipped from time to time. But, of course, every 
 well-equipped workshop should be provided with a dental 
 engine. 
 
 To polish the teeth. This is a process which I seldom 
 find it necessary to carry to any great length. An Arkansas 
 stone run in the dental engine and kept wet gives a very fine 
 surface. No. 1 glass paper used dry will add a further gloss. 
 Where a yet finer surface is desired, I use a buff carrying 
 putty powder, and finally finish with whiting. 
 
 The following articles for the double purpose of grinding 
 and polishing will meet all requirements. 
 
 Equipment fur use with the Dental Lathe: 
 
 (1) A carborundum or corundum wheel for grinding the 
 tooth to shape. 
 
 (2) An Arkansas wheel or an Ash's polishing wheel for 
 removing the marks left by the carborundum or corundum 
 and for smoothing the ground surface. 
 
 (3) A brush or buff wheel, some superfine pumice or 
 putty powder and some whiting for polishing. Note — water 
 to bo used at overy stage. 
 
 2 — 2 
 
20 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 Equipment for the Dental Engine: 
 
 (1) Carborundum or corundum wheels and points. 
 
 (2) An Arkansas or Water of Ayr stone. 
 
 (3) A brush or buff polisher, some superfine pumice &c, 
 as under No. 3 above. 
 
 Equipment for hand use: 
 
 (1) A half round carborundum or corundum file. 
 
 (2) A hone of Arkansas or Water of Ayr stone. 
 
 (3) A hand buff, some superfine pumice &c, as under 
 No. 3 of Dental Lathe equipment. 
 
 To shorten a tube-tooth. If Ash's tube-teeth are 
 shortened by a forcible grab with the cutters usually supplied, 
 
 Fig. 10. 
 
 they are very apt to be splintered and otherwise damaged in 
 a way that gives much trouble, even if it does not altogether 
 
SOME METHODS IN PRACTICE. 21 
 
 spoil the teeth. The cutters which I use (Fig. 10), and 
 which are not nowadays figured in the catalogues, consist of 
 two chisel-like edges facing each other, the upper one being 
 capable of up and down movement so as to somewhat 
 resemble a miniature guillotine. Placing the tooth to be 
 shortened between these edges, I give the back of the upper 
 edge a tap smart enough to just crack the tooth through to 
 the tube ; then with a thrust of a sharply tapering steel rod 
 inserted in the tube, I am able to burst off the superfluous 
 part of the tooth without in the least damaging the part 
 required. The exposed portion of the tube is then, of course, 
 easily sawn off. 
 
 To mark the positions of the pins for tube-teeth. 
 
 Having roughly ground down and adapted a tooth to the 
 position intended for it, I fasten it temporarily to the plate, 
 and, passing through the tooth a broach, sharpened as a drill, 
 large enough to nearly fill the tube, and carried in a socket 
 handle such as is used for hand-burs, I mark the position 
 for the pin, taking care to support the tooth while doing so. 
 Then, taking a much finer broach sharpened as a drill and 
 carried in a drill-stock, I drill a hole for the pin in the 
 position marked, the mark having been made sufficiently 
 deep to prevent the drill from slipping in ordinary cases. 
 Should the mark happen to be on a steeply sloping part of 
 the plate and not on the top of the ridge, to avoid the slipping 
 of the broach while drilling, I first drill a small hole nearly 
 through the plate at the mark, holding the broach mean- 
 while almost perpendicular to the plate at that point. Then, 
 slipping the tooth on to the broach and using it as a guide 
 for the direction in which to proceed, I finally enlarge the 
 hole to the size required for the pin. 
 
 Soldering pins to plates. When pins for tube-teeth 
 are to be soldered to a plate, the use of wire to tie them in 
 position may be avoided by placing a good-sized lump of 
 asbestos fibre upon the wig and by so resting the plate upon 
 it that the pin to be soldered shall be vertical, or shall lean 
 
22 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 slightly away from the direction in which, at the moment of 
 soldering, it has a tendency to fall. 
 
 Asbestos is a good material to use as a support, as it is 
 light and takes up but little heat. A small quantity will 
 last an indefinite time. 
 
 Fitting a gold plate with side-pieces for swivels. 
 
 Though somewhat of a digression, a description may con- 
 veniently be given here of my method of proceeding when 
 fitting side-pieces to a gold plate. 
 
 The teeth being in position on the pins, I remove two 
 at some distance from, and on either side of, the position 
 intended for the side-piece, and, twisting a piece of wire 
 round one of the exposed pins, I pass it along the front of 
 the teeth remaining in position, past the position for the 
 side-piece, and on to the other exposed pin round which 
 
 I secure it (Fig. 11). Then, re- 
 nt di n I / / ~W moving all the teeth and pushing 
 il ri ill I ° jt o 
 
 jffJ gFB l Ig™/^Rn I the wire its own width nearer to 
 
 y L— *^ \_^ • the pins, I bring the outer side 
 
 "*=i^--= -^fc^^^- of the wire to the position of the 
 
 surface of the teeth previously 
 touched by it. Assuming that the plate has already been 
 marked along the necks of the teeth, I next apply ground 
 borax to that part of this mark at which the side-piece is to 
 be fixed, place the side-piece there, and, leaning it against 
 the wire above-mentioned, I proceed to complete the 
 soldering. 
 
 Backing and soldering teeth. When backing a tooth, 
 my plan is to counter-sink the back and rivet with a fine- 
 edged hammer, supporting the tooth meanwhile on the edge 
 of a piece of lead held in a vice. This I think better than 
 splitting and spreading the pins, as some recommend, because 
 the borax and solder are more easily kept from flowing 
 through the back and fracturing the tooth. In soldering I 
 use a jeweller's wig on which is placed a sprinkling of 
 asbestos fibre to prevent the discoloration and cracking of 
 
SOME METHODS IN PRACTICE. 2o 
 
 the teeth, the soldering being done without investing. The 
 teeth are then allowed to cool, and the backs are filed up 
 before the teeth are waxed in position on the plate. When 
 in position, the teeth are invested in sand with a slight 
 admixture of plaster, and the final soldering is done in the 
 usual way. 
 
 In making a gold bicuspid crown with a mineral face, I 
 am able by the above method, that is with asbestos fibre on 
 a jeweller's wig, to make use of the mineral face to hold the 
 back in position while tacking the back to the crown, and 
 this without investing and without cracking or discolouring 
 the face. Then, removing the face, I complete the soldering. 
 To fasten the tooth to the back I merely bend the pins 
 towards the cutting edge of the tooth and do not solder 
 them. 
 
 To solder a post in a tube-tooth. When making a 
 dowel-crown with a tooth in which the dowel is not already 
 fixed (see page 82), I insert the thick or root end of the post 
 
 Fig. 12. 
 
 or dowel into a light copper tube with an open seam (Fig. 12) 
 which will hold it without carrying off too much heat; tin 
 the end of the post which is to enter the tube of the tooth ; 
 apply zinc-chloride as a flux to tube and post ; lodge the 
 tooth on the point of the post; hold over a gas-flame and 
 drive the tooth home, being careful that the post takes its 
 proper position, which in the case of an ordinary tube-tooth 
 will be shown by the facet at the end of the post properly 
 fitting the surface of the tooth. 
 
24 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 Soldering a pin-tooth to a plate in the neighbour- 
 hood of a band. In the process of soldering a pin-tooth to 
 a plate next to a band, the solder is apt to flow between the 
 edge of the plate and the band, and so render the band rigid 
 just where it is required to be free. This may be prevented 
 by rouging the band, but the band should be rouged and 
 dried over a gas- flame before the tooth is waxed into position 
 for soldering. There will then be no risk of rouge getting 
 on to the back of the tooth, or between the back and the 
 plate, and so obstructing the flow of the solder to places 
 where it is required. 
 
 To cement tube-teeth to a gold plate. In cementing 
 the teeth to the pins on a gold plate, I warm the pins and 
 dip them one after another in a spoonful of melted sulphur. 
 Then heating a tooth held in grooved pliers, I set light for 
 an instant to the sulphur on a pin, blow it out, and force the 
 tooth home, taking care that the tooth is hot enough to melt 
 the sulphur as it passes on to the pin, and proceeding in the 
 same way with the other teeth till all are on. If the plate is 
 of all-gold, it may be warmed to assist the operation. 
 
 To make silver solder and gold solder. It may 
 
 perhaps be useful if I add here a description of the methods 
 by which I make silver solder and gold solder : 
 
 Take 8 dwt. of sterling silver; melt it; wrap 4 dwt. of 
 ordinary brass pins with plenty of ground borax in paper, 
 and drop the packet into the molten silver, stirring with the 
 stem of a clay pipe. Cast, and roll. The alloy obtained is 
 silver solder. 
 
 Add 8 grs. of this alloy to 1 dwt. of any gold to be 
 worked with, and you have the quality of solder suitable for 
 that gold. In adding the alloy to the gold proceed as 
 follows : 
 
 Melt, say, 3 dwt. of gold ; paint 1 dwt. of silver solder 
 with ground borax ; drop it into the molten gold ; stir with 
 a pipe stem ; cast and roll, and you have 4 dwt. of gold 
 solder. 
 
SOME METHODS IN PRACTICE. 25 
 
 Polishing wheels and points. Since writing the 
 above notes (pp. 18 — 20) on the grinding and polishing of 
 Ash's Mineral Teeth, I have received from Mr Brunton a 
 number of wheels and points of his invention by the use of 
 which a very satisfactory surface is produced without further 
 polishing. The shanks on which the engine wheels and 
 points are carried are made thin towards the wheel or point 
 to facilitate access to difficult parts. The shanks are also 
 furnished with small washers to prevent moisture from 
 getting into the hand-piece. 
 
 To centre wheels upon a lathe. In cases where the 
 spindle of the lathe is too small for the hole in the wheel to 
 be centred, the adjustment may readily be made by wrapping 
 a strip of soft sheet-copper of the requisite thickness about 
 the spindle. The collar thus formed should be left open at 
 the seam, and the strip from which it is made should be 
 rather narrower than the thickness of the wheel, so that the 
 collar may not take the pressure of the washer or nut from 
 the wheel, when the nut is screwed tight. In putting on a 
 wheel, first slip a suitable collar into the hole in the wheel, 
 and then slip collar and wheel together on to the spindle. 
 
 Method of wetting wheels on the lathe. The use 
 
 of dripping water and a sponge for wetting wheels on a lathe 
 to which I was accustomed as an apprentice is objectionable 
 as being both messy and inefficient, and for the last 33 years 
 I have used a pan or trough of water. This stands under the 
 wheel and behind a rail fixed to the bench for the hand to 
 rest upon. The result is that there is no splashing, the 
 debris from grinding is wholly taken up by the water into 
 which it sinks, the wheel is kept constantly clean and 
 thoroughly wet, and, in the case of carborundum, the cutting 
 qualities appear to be actually improved by the soaking. 
 
 Repairing a cracked vulcanite plate. A few words 
 upon the repair of a cracked vulcanite plate may well bring 
 these few remarks upon methods to a close. For a method 
 of preparing a die and counter and striking up a plate for 
 use in such cases the reader is referred to the chapter on 
 
26 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 fusible metal (page 44). Such plates are usually attached 
 to the vulcanite by drilling and riveting, but there are cases 
 in which, owing to the position of the teeth, it is impossible 
 to rivet the plate sufficiently close to them to prevent move- 
 ment of the parts near them. Such cases may, however, be 
 very effectively repaired by attaching a small thick plate quite 
 close to the teeth by means of short, rapidly tapering screws. 
 The method of making such screws is described on p. 32. 
 It should be added that in riveting to vulcanite, while it 
 is necessary to countersink the plate, in the vulcanite no 
 countersinking is required. It is even attended by disad- 
 vantage, as a trial will readily prove. 
 
 To remove the model from the sand when about 
 to cast a zinc. There is a hint, which it may be worth 
 while to add, on the method of removing the model from the 
 sand, when about to cast a zinc. The common method of 
 driving a sharp point into the model, especially when the 
 model is thin or over-dried, is a troublesome and sometimes 
 risky operation often attended by failure. If by another 
 method small portions of the sand are removed so that the 
 model may be lightly grasped, the zinc comes out with some 
 unwelcome additions, however small. 
 
 A better plan than either of these is to let fall a drop of 
 wax upon the centre of the back of the model when em- 
 bedded in the sand, or earlier if a Pearsall flask be used, 
 and to press down upon the wax a heated metal disc, say a 
 farthing, furnished with a handle, which may be a second 
 farthing standing edgewise on the first and soldered to its 
 centre. By this handle the model can be lifted without the 
 least risk of its falling back ; and a very little heat applied 
 to the disc suffices for its removal from the model as well as 
 for its attachment to it. 
 
CHAPTER II. 
 
 A FEW TOOLS AND INSTRUMENTS. 
 
 In this chapter I propose to devote a few words to cer- 
 tain tools and instruments, in some of which I hope to be 
 able to suggest improvements, and it will perhaps interest 
 those who take pleasure in making their own tools, if, in the 
 first instance, I briefly refer to such as I make for myself. 
 
 First in order of use among these, but so simple as hardly 
 to deserve mention, is a contrivance for saving impres- 
 sion trays (Fig. 13) from damage when rapping them in 
 
 Fig. 13. 
 
 order to shake down the plaster into the impression. It 
 consists of a piece of wood, some inches long and of triangular 
 section, which consequently, when placed upon the bench, 
 presents one edge upwards. Upon this edge a piece of 
 rubber tubing is tacked, and upon this tubing trays may be 
 rapped quite harmlessly. 
 
28 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 Another point in connexion with trays may be men- 
 ^^ tioned here. If, when a model 
 
 \ has been cast and the plaster is 
 
 «*> set, an attempt is made to remove 
 the tray by heating the composi- 
 tion in hot water, some of the 
 composition is apt to remain ad- 
 hering to the tray, and is then 
 very troublesome to remove. If, 
 on the other hand, cold water 
 from a tap be allowed to run 
 over the tray so as to get rid 
 of the heat generated by the set- 
 ting of the plaster, and causing 
 the adherence of the tray, the 
 tray may be readily removed in a 
 perfectly clean state by inserting 
 a knife between the tray and the 
 composition, at one or both heels 
 of the tray. 
 
 For cutting up vulcanite 
 work, I make two bent 
 scrapers, one from the handle 
 of an old gold file (Fig. 14), the 
 other from an old hand-bur (Fig. 
 15). 
 
 In the case of the old gold 
 file, I soften the handle ; make 
 one side quite flat and smooth ; 
 then turn up the end, while hot, 
 flat side inwards ; file into shape, 
 and harden. To sharpen, I have 
 only to grind the outer side of 
 the bend at the margin, when 
 the smoothness of the inner side 
 of the bend gives a good cutting 
 Fig. 14. Fig. 15. edge. In the case of the hand- 
 
A FEW TOOLS AND INSTRUMENTS. 
 
 29 
 
 bur, I soften and flatten the bur ; grind the disc so obtained 
 flat on one side ; bend up towards that side ; harden and 
 sharpen, as before. The excellence of the material from 
 which the files and burs are made leads me to prefer the 
 scrapers thus obtained to those supplied by the depots. 
 
 Among other tools for the same purpose I have a 
 scraper made from a three-sided file, a knife-edged 
 file, and an oval root-file for going inside lowers. 
 
 For removing vulcanite from between the teeth 
 I use an old excavator brought to a needle point : this 
 is also of use in shortening tube-teeth as already described 
 (p. 20). 
 
 For waxing up a case I have an old pocket knife 
 
 with the small blade brought to a point by grinding away its 
 
 Fig. 16. 
 
 original point until both back and edge are straight but the 
 back the shorter, thus : (Fig. 16). A piece of copper wire 
 heated is also useful in such work. The large blade of the 
 knife is used for trimming plaster when investing. 
 
30 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 For scollopers and gouges I discard the handles 
 usually supplied for them, and fit them 
 with handles such as engravers use. To 
 do this, the handle end of the scolloper, 
 say, is bent at right angles and brought 
 to a point. This point is driven into the 
 side of the piece of wood intended for 
 the handle, and cord is then used to bind 
 the scolloper to the handle (Fig. 17). In 
 this way the gouges and scollopers can 
 be made to project a convenient distance 
 from the handle at the outset, and can 
 be lengthened from time to time as re- 
 quired, whereas with the handles supplied 
 they project at first too far, and there is 
 a temptation to be wasteful by breaking 
 them short. 
 
 I may add that I find it useful to 
 chamfer the two edges of the back of 
 the scollopers ordinarily supplied, in 
 such a way that the back may be nar- 
 rower than the front. 
 
 To the use of a socket-handle for 
 
 hand -burs as a means of carrying a 
 broach to be used as a drill I have al- 
 ready referred (p. 21). 
 
 To save the waste which attends 
 the use of naked gold cutters and the 
 
 worry which is caused by the endeavour 
 to catch the clippings, I draw a piece of 
 india-rubber tubing over the jaws (Fig. 
 18). As the clipping goes on, the pieces 
 are caught in this tubing or sheath with- 
 out any attention on the part of the workman, and are 
 readily emptied out when the clipping is done. The tubing 
 perishes, of course, after a time and becomes ineffective, but 
 is easily renewed. 
 
 Fig. 17. 
 
A FEW TOOLS AND INSTRUMENTS. 
 
 31 
 
 Of instruments for use in the surgery I may men- 
 tion a small saw (Fig. 19) which will 
 cut in a direction at right angles to 
 the plane of its frame, and which is 
 consequently useful for removing the 
 crowns of incisors when the roots are 
 to be crowned. Finding the frames 
 of saws of this kind, as supplied by 
 the depots, deficient in substance, I 
 made one for myself by adapting the 
 frame of a piercing-saw. To do this 
 I had merely (1) to shorten, and cut 
 slots in, the sides of the extremities 
 of the frame to receive the saw-blade, 
 and (2) to prevent the blade from 
 pulling out, when in action, by attach- 
 ing a small bead of solder to either 
 end of the blade. This bead is obtained 
 by making the end of the saw-blade 
 bright, dipping it in a solution of zinc 
 chloride, then in melted solder, again 
 melting in the gas-flame the solder 
 which adheres, and tilting the blade so that the solder runs 
 to the end of it and forms the bead desired. The blade is, 
 
 Fig. 18. 
 
 Fig. 19. 
 
 of course, cut in the first instance of such a length that 
 there is just sufficient length left between the beads to suit 
 the frame. 
 
32 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 The screw-cutting pliers shown in Fig. 20 were 
 designed in the first instance with 
 straight slender chops, closing only 
 at the extremities, for the purpose 
 of grasping a strip of copper about 
 a bicuspid root when crowning by a 
 method to be described later on. 
 Without further addition they were, 
 and are still, a useful tool in the 
 workshop for general purposes, in 
 particular for bending the pins in 
 pin-teeth, and for adjusting the 
 pins for tube-teeth, the long slender 
 chops especially fitting them for 
 these purposes. But a suggestion 
 gained from seeing the late Dr J. 
 J. R. Patrick of Belleville, Illinois, 
 at work with a screw-cutting ap- 
 pliance of his own, when on his last 
 visit to England, has enabled me 
 to suggest the addition of a very 
 
 Fig. 21. 
 
 valuable feature to these pliers without in any way detracting 
 from their usefulness for the purposes for which they were 
 originally designed. This addition consists of a screw-thread 
 cut in the chops, by means of which a thread may be cut on 
 a tapering wire. In this way a tapering screw post is 
 obtained which will tap for itself a root to be filled or 
 crowned. For the opportunity of seeing Dr Patrick I am 
 indebted to Dr G. Cunningham. 
 
 The method of making a screw post is as follows : 
 
 File a piece of wire, of dental alloy for choice, to a suitable 
 taper as shown at the right-hand end of the piece of wire 
 represented in Fig. 21, and, holding the wire in a hand- vice, 
 
A FEW TOOLS AND INSTRUMENTS. 33 
 
 grasp the thick end of the taper first with the pliers, and 
 gradually work out the wire from the pliers. Repeat this 
 three times, beginning always at the thick end of the taper. 
 The pressure on the pliers should be steady and oil should 
 be used. For the method of inserting such a post into a 
 tooth see page 36. 
 
 A further addition to these pliers was borrowed from 
 an advertisement and consists in a plain orifice, nearer the 
 base of the chops, for inserting and removing cone-socket 
 points. 
 
 I may perhaps be forgiven if I recall here that at 
 Glasgow in 1887 I showed a cervical clamp to which 
 clamps afterwards advertised under the names of Dr St 
 George Elliot and Dr J. Leon Williams bear a strong 
 family likeness. I am not in a position, and do not wish, 
 to argue the question of priority, but I claim that the 
 screw cervical clamp I then showed was original so far as 
 I was concerned. 
 
 Fig. 22 shows a modified form 
 of this clamp, the rear limb having 
 a screw adjustment by means of 
 which the length of the limb can 
 
 be adjusted to suit any given tooth. 
 
 mi • '• Fig. 22. 
 
 Inis is new. 
 
 ■ There are three other articles in which I am able to 
 suggest modifications which I hope will prove useful. 
 
 The first of these is the hot-water syringe for washing 
 out cavities. The syringe in ordinary use has several 
 disadvantages. It takes a long time to fill, the water is 
 consequently much cooled during the process of filling, and, 
 wh.n the water is cold, time is again lost in expelling it from 
 the syringe. 
 
 The syringe shown in Fig. 23 is furnished in the nozzle 
 
 with a valve actuated by a light spring. When the syringe 
 
 is to be filled, the neck of the bulb, just above the milled 
 
 nut, is taken between the forefinger and the middle finger, 
 
 L. 3 
 
34 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 the bulb is compressed either by the thumb acting on its 
 base or by the remaining fingers and the palm of the hand, 
 and the valve is at the same time opened by pressing the 
 nozzle against the bottom of the vessel containing the hot 
 
 Fig. 23. 
 
 water. The bulb being quickly filled and the nozzle with- 
 drawn from the water, the valve is closed by the action of the 
 spring, and the syringe is ready for use in the ordinary way, 
 or it may be emptied again immediately by pushing back 
 the nozzle while compressing the bulb. Whether to fill or to 
 empty the syringe but one hand is needed. 
 
 The second article referred to above is the ordinary 
 vulcanite flask. When a case is invested in one of these 
 
 flasks in the manner described 
 on page 12, it is difficult, 
 owing to the sides of the 
 flask being equally deep at 
 all points, to get at and re- 
 move the superfluous plaster 
 about the extremities of the 
 plate. I have accordingly 
 varied the depth of the rear 
 side of the flask in the 
 manner shown in Fig. 24. 
 A further difference from the ordinary flask is the 
 adoption of guides, the front edges of which slope backwards 
 
 Fig. 24. 
 
A FEW TOOLS AND INSTRUMENTS. 
 
 35 
 
 from the vertical and so allow the parts of the flask to be 
 brought together in a manner suited to 
 plates in which a section through the 
 central line would present a hooked 
 
 Fig. 25. 
 
 appearance, as shown in Fig. 25. I have 
 been obliged for many years to file away 
 the ordinary upright guides to meet cases 
 of this sort. 
 
 A third article with regard to which 
 I have a suggestion to make is the wire- 
 or broach-holder. This is of great use 
 in inserting screw-posts, but if the holder 
 is small and light, as it should be for use 
 at the mouth, there is difficulty, owing to 
 the smallness of the milled nut, in screw- 
 ing it up tightly enough to give the holder 
 sufficient purchase upon the tapped wire, 
 and its slipping involves an annoying loss 
 of time. Fig. 2(5. 
 
 Accordingly, having made a groove 
 along the nut, I have fitted to the latter a small spanner 
 (Fig. 26) with a feather corresponding to this groove, and 
 have since had no difficulty in making the holder grasp the 
 wire securely. 
 
 It would, however, save the addition of the above spanner 
 to the already over-large number of instruments we require, 
 
 3—2 
 
3G 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 if an extra hole were made in the engine-spanner to fit the 
 
 nut of this broach -holder. 
 
 To insert a tapped-wire post into a 
 O tooth, fix the tapped wire tightly in a broach- 
 holder and screw it into the tooth, thus tap- 
 ping the tooth by means of the post itself; 
 mark the length required for the post by 
 means of a bristle dipped in chloro-percha ; 
 remove the wire from the tooth ; make a 
 nick in it at the point marked, and again 
 screw it home into the tooth until it breaks 
 at the point where the nick was made. 
 Sometimes, before breaking the wire, my 
 partner replaces it temporarily by a gutta- 
 percha point equally thick but less obstruc- 
 tive. 
 
 Fig. 27. 
 
 Some simple tools I made years ago for 
 use in affixing heads to swivel-bolts may 
 
 perhaps deserve mention, as the making and 
 using of such tools would furnish useful exer- 
 cises for students. 
 
 The first of these (Fig. 27) consists of a 
 large round file in the end of which a hollow 
 has been drilled, the margin of the hollow 
 being brought to a sharp edge by filing and 
 rubbing on a stone. By driving this tool 
 through a piece of sheet-gold (No. 5 or 6 
 Ash's gauge) placed upon lead, we may cut 
 out and dome up a bolt-head at one blow. 
 
 The second tool (Fig. 28) is a piece of 
 tinned iron cut and bent into something 
 resembling a pair of sugar-tongs, having at 
 one end a sort of spoon fitted to receive the 
 bolt-head, and at the other a merely flat 
 surface. The tin is, of course, burnt off the 
 iron before making up this tool. 
 
 The purpose of the tool is to hold the 
 
A FEW TOOLS AND INSTRUMENTS. 
 
 37 
 
 bolt and the bolt-head in position while soldering them 
 together. The bolt-head should be filled with solder and 
 the surface of the solder should then be made flat. 
 
 Fig. 28. 
 
 This is done by means of a third tool (Fig. 29) which 
 consists of an old excavator handle, down the centre-line of 
 which a hole has been drilled for, say, about a quarter of 
 an inch. A part of the side of the handle is cut away to 
 
 Fig. 29. 
 
 beyond the centre-line so that the far end of the hole before 
 drilled becomes exposed ; the end of the handle is filed or 
 turned to the size of the bolt-head and the extremity is made 
 flat and smooth. 
 
 The bolt having been boiled in pickle is inserted into the 
 bole in this tool and driven down with a few taps from a 
 small hammer, until the solder is flat and smooth. The head 
 of the bolt is then filed and polished, and the bolt is re- 
 moved from the tool by means of the opening at the side. 
 
 It is obvious that with bolts made in this way, a silver 
 bolt and silver solder can be used without detriment to the 
 appearance of the work, the head being of gold. 
 
 A convenient tool for making a flat surface of the 
 proper size to receive the swivel, or a washer for the 
 
 swivel, in a vulcanite case, may be made from an old gold file 
 
38 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 by cutting the end into the form of a centre-bit as shown in 
 Fig. 30. The tool should be carried in a 
 socket-handle. 
 
 Before concluding these few remarks about 
 tools and instruments, I feel bound, if only in 
 justice to my friend, Mr F. Thomas, of Jesus 
 Lane, Cambridge, to give a brief account of 
 the Pneumatic Mallet (Fig. 31) with which 
 our names are associated and which upon my 
 call for help he so quickly and ably devised. 
 Moved by the complaints of my partner about 
 the inefficiency of the mallets he had tried, I 
 applied to Mr Thomas, whom I knew to be an 
 inventor by nature and accustomed to make a 
 variety of scientific instruments for men of 
 science in the university. In a very few days, 
 he produced the idea which was ultimately 
 developed into the perfected instrument as 
 shown at Exeter in 1890, and I felt and feel 
 so satisfied with it that I have never hesitated 
 and do not now hesitate to endeavour to im- 
 press operators with a sense of its utility. Its 
 action is of the simplest kind, and it is re- 
 markably free from liability to get out of order. 
 A comparatively imperfect instrument of the 
 kind was used by my partner for years without 
 needing any attention to speak of. If there is 
 any drawback to its use, it lies in the fact that, 
 as placed upon the market, it has to be driven 
 by a Fletcher's blower which must either be 
 worked by the operator himself or by an at- 
 tendant. But this is no fault in the mallet as 
 such, and those who object to either alterna- 
 tive might readily avoid them by the use of 
 air-pressure derived from a species of gasometer 
 which could easily be contrived so as to give sufficient air- 
 pressure for a day's work. 
 
 Fig. 30. 
 
r\ 
 
 Fig. 31. 
 
40 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 A reference to the section of the mallet shown in Fig. 32 
 will make its construction and action clear. The air entering 
 from a rubber tube at the end H opposite to the plugger E 
 passes between the larger outer cylinder and the smaller 
 inner one and enters a small central chamber G in the inner. 
 This chamber has openings or windows at both ends into the 
 inner cylinder. These windows are alternately closed and 
 opened by means of a valve or shutter M which moves freely 
 along the piston rod CO passing through its centre and 
 carrying at its ends pistons BB' which fit loosely in the end 
 chambers A A' of the inner cylinder. Starting from either 
 piston and coiled along the piston rod are two springs NN' 
 of unequal length. 
 
 The air entering the central chamber drives the valve or 
 shutter over to the nearer window in that chamber, passes 
 through the open window at the other end of the chamber 
 and drives before it the piston at that end until the spring 
 attached to the other piston strikes the shutter and pushes 
 it over to close the other window. The action is then re- 
 versed. The air now acts upon the other piston and drives 
 it away in turn until the other spring, attached to the piston 
 first acted on, in its turn strikes the shutter and drives it 
 over to the window first closed. The air in front of a piston 
 which is being driven away either escapes directly through 
 an opening made by moving the ratchet Q near the 
 plugger, if the piston is that nearest the plugger, or escapes 
 first through the piston rod which is hollow and so out by 
 the same opening as before. It is clear that so long as this 
 opening is closed the instrument remains at rest and the 
 operator is, therefore, able by letting slip the ratchet to stop 
 the mallet at once. 
 
 The plugger is so arranged that the nearer piston strikes 
 it like a hammer towards the end of its stroke, and there is a 
 contrivance by which the socket holding the plugger and the 
 plugger itself can be brought nearer or removed farther from 
 this piston, with the result in the first case that the blows 
 become lighter and faster, and in the second case slower and 
 heavier, and it is obvious that a wide range of blows may be 
 
A FEW TOOLS AND INSTRUMENTS. 
 
 41 
 
 thus obtained from the very hardest 
 to a scarcely perceptible touch. 
 
 The instrument readily gives up- 
 wards of 1000 blows a minute, as may 
 be easily proved by allowing it to 
 strike a sheet of paper while working 
 for, say, five minutes and then dividing 
 the number of dots made by the 
 number of minutes in which they were 
 made. The variety in the force of 
 the blows may be similarly tested by 
 allowing the plugger to strike a sheet 
 of lead and noting the depth of the 
 indentations. 
 
 The plugger points are easy to 
 insert and remove, but when a rapid 
 succession of different pluggers is de- 
 sired, it becomes a nuisance to have 
 to insert and remove them. This is a 
 difficulty incidental to all mallets, but 
 with this mallet might be readily 
 overcome by suspending five or six 
 mallets at once by separate rubber 
 tubes all connected with one metal 
 cross-tube supplied by a main tube 
 from the blower or gasometer. The 
 operator could then catch up any one 
 of the six he chose, and, the others 
 remaining inert, he would still have 
 the full force of the air supply through 
 the one he was working with. 
 
 The success which this mallet has 
 met with hitherto has unfortunately 
 not been such as to reward Mr Thomas 
 for the ingenuity and labour expended 
 upon it, but for those who need a mallet 
 and do not rely entirely upon hand 
 pressure I am satisfied that there is no 
 more effective instrument to be had. 
 
 H 
 
 3 
 
 !! ». 
 
 H 
 
 Fig. 32. 
 
42 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 I append a detailed description of the sections of the 
 instrument shown in Figures 32 to 36. 
 Figure 32 is a longitudinal section. 
 Figure 33 is a section on the line XX (Fig. 32). 
 Figure 34 is a section on the line YY (Fig. 32). 
 Figure 35 is a section on the line ZZ (Fig. 32). 
 Figure 36 is a side elevation of one of the parts. 
 
 Fig. 33. 
 
 AA' are two cylinders in which work the pistons BE' 
 which are fixed to a common piston rod G, the end of which 
 strikes against the holder D which carries the plugger E, 
 F being a spiral spring which tends to bring the parts D 
 and E back again after a blow. G is the valve chamber 
 which is connected by the flexible tube H to bellows or 
 other air-forcing apparatus. 
 
 The air enters by the pipe J, passes along the radial 
 passages K to the longitudinal passages L formed between 
 the outside of the cylinder A and the casing of the in- 
 strument to the valve chamber G in which works the valve 
 M sliding upon the piston rod. The valve M is actuated by 
 the spiral springs NN'. 
 
A FEW TOOLS AND INSTRUMENTS. 43 
 
 When the parts are in the positions shown in Fig. 32, 
 air is being admitted from the valve chamber G into the 
 cylinder A' and is tending to force the piston B' forward. 
 As soon as the aperture in the casing is opened by pushing 
 forward the tube P by means of the serrated thumb-piece Q 
 fixed to it, the piston B' will move forward and the blow will 
 be struck. Meanwhile the spring N will have been com- 
 pressed and the spring N' relieved so that the valve M will 
 be shifted so as to cut off air from the cylinder A' and admit 
 it to the cylinder A, when the reverse action takes place, the 
 motion continuing so long as the opening is uncovered by 
 the tube P, and the rapidity of the blows can be varied by 
 more or less covering the opening 0. 
 
 The piston rod is made hollow so that air from the 
 cylinder A as well as that from the cylinder A' escapes 
 through the opening 0. 
 
 The instrument is also furnished with a milled nut at the 
 plugger end (not shown in the section Fig. 32). by giving 
 partial turns to which the distance of the plugger E and its 
 holder D from the end of the piston rod G can be varied 
 whereby the force and rapidity of the blows admits of nice 
 adj ustment. 
 
 As shown in the drawings, the piston B' forms a nut 
 upon the screw-threaded piston rod and is grooved as shown 
 in Figures 32 and 35 to receive a feather upon the casing so 
 that by turning the casing the distance of the pistons apart 
 can be varied. 
 
 In some cases a fixed stop or abutment is provided to 
 receive the blow at times when it is not desired that the 
 holder carrying the plugger should be struck. A spring is 
 applied in connexion with the plugger-holder in such manner 
 as to press it forward away from the striking end of the 
 piston rod. The blow is then struck upon the fixed stop, 
 and only reaches the plugger when by pressure exerted by 
 the operator with the point of the plugger the spring is 
 compressed and the plugger-holder is caused to recede until 
 it comes within range of the blow. 
 
CHAPTER III. 
 
 SOME USES FOR FUSIBLE METAL. 
 
 The following is an account of the various uses for 
 Fusible Metal described by me in a paper read before the 
 London Meeting of the British Dental Association in 1891. 
 
 Full information as to the constitution of the several 
 alloys to which the name of Fusible Metal has been given 
 and as to the several temperatures at which they melt 
 may be readily obtained from the text-books of Chemistry 
 and from Harris's Dictionary. I will therefore only say in 
 passing that these alloys are made up of lead, tin, and 
 bismuth with or without cadmium ; that they melt at 
 varying temperatures below the boiling point of water, and 
 expand about 3 per cent, on cooling, thereby affording a 
 very sharp impression even of fine scratches on the object 
 from which a cast is taken with them. 
 
 Having for many years had a small piece of one of these 
 alloys in my possession, I found occasion in the autumn 
 of 1890 to make some experiments with it, and, one thing 
 leading to another, I had the good fortune to arrive at the 
 several ways of employing it which I am about to explain. 
 
 These ways are three in connexion with crown-work, two 
 with the repair of vulcanite plates, and three with the manu- 
 facture of new plates. 
 
SOME USES FOR FUSIBLE METAL. 45 
 
 First, as regards crown-work. In this class of work the 
 metal may be used : — 
 
 (a) To make a mandrel for shaping the ferrule or collar. 
 
 (b) As a setting for a natural tooth, to be used as a die 
 for striking up crowns. 
 
 (c) As a means of obtaining a well-defined and not 
 readily damaged cast of the mouth when a tooth is to be 
 pivoted. 
 
 The mandrel, of which a specimen is shown in Fig. 37, 
 is obtained as follows : — 
 
 A thin strip of copper (Fig. 38), in the form of a portion 
 of a flat ring, is formed into a ferrule, with plane edges and a 
 
 Fig. 38. 
 
 Fig. 37. 
 
 flaring top (Fig. 39), by placing the strip about the root 
 to be crowned, grasping the ends with a pair of pliers 
 (Fig. 40) and drawing them together until the lower edge 
 of the strip, which edge alone comes into contact with the 
 root, takes accurately the form of the latter a little under 
 the gum margin. The ferrule is then soldered, trimmed 
 at the lugs, replaced on the tooth (Fig. 41), lightly filled 
 
4fi 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 to the edge, but not over it, with wax when so placed 
 (Fig. 42), and an impression is taken in composition. The 
 impression being removed from the mouth, the ferrule, if 
 disturbed, is carefully replaced in position in the impression 
 (Fig. 43) and filled level full with wax which must leave the 
 edge clear. Half an ordinary brass pin is thrust head down- 
 wards into the wax towards the buccal side of the ferrule 
 (Fig. 44), and a model is cast in plaster (Fig. 45). Next, the 
 
 Fig. 41). 
 
 ferrule being in position on the model, the wax is removed 
 exposing the pin, and a small depression is cut in the plaster 
 within the ferrule towards its lingual side (Fig. 46) by 
 means of the spade-shaped excavator (Fig. 47). Fusible 
 metal from the cup (Fig. 48), which has been standing in 
 boiling water, is now poured into the ferrule, and a slight 
 pressure is applied with the finger to the cooling metal with 
 the result shown in Fig. 49. This gives us the mandrel 
 (Fig. 37). Should there be any defect in it at the first 
 
SOME USES FOR FUSIBLE METAL. 
 
 47 
 
 attempt, the metal may be remelted with the handle of 
 an excavator made hot. It is as well before casting the 
 mandrel to withdraw the pin from the cast and replace it, 
 in order that it may be the more easily removed afterwards. 
 The pin is useful in handling the mandrel, while the pin 
 and the boss (A, Fig. 37), corresponding to the depression in 
 
 Fig. 41. 
 
 Fig. 42. 
 
 Fig. 43. 
 
 Fig. 44. 
 
 Fig. 4.'.. 
 
 Fig. 46. 
 
 the model, together serve as guides in placing it. Figures 
 50 and 50 a show mandrels in position on models, ready fi it- 
 use. 
 
 The method of using such a mandrel will be described in 
 the course of the few words T propose to say later on upon 
 Crowning. I will only cull attention here to the readiness 
 
48 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 with which by means of it the depth of the gold collar or 
 ferrule may be determined and the festoon obtained. 
 Figure 51 shows a method of obtaining a ferrule, 
 such as that shown in Figure 39, of any given dimen- 
 
 Let OA represent the least, OB the greatest 
 diameter (or girth) of the desired ferrule. At 
 
 Fin. 47. 
 
 Fig. 48. 
 
 and A set up perpendiculars to OA, and from these 
 mark off OD and AG equal to the depth of the 
 ferrule required, that is, to the distance between the 
 greatest and the least girth. Draw BO and produce 
 it to meet OB in E. With centre E and radii OE, 
 BE, describe the arcs OG, BF. Take the arc OG 
 equal to the greatest girth of the desired ferrule 
 and join EG. The shaded strip FBOG will bend 
 up into a ferrule of the given dimensions. 
 
 In this way the curvature necessary to adapt a 
 copper strip (Fig. 38) to any given tooth may be 
 ascertained by taking OA equal to the girth of the 
 tooth at the gum margin, OB equal to its greatest 
 
SOME USES FOR FUSIBLE METAL. 
 
 49 
 
 girth, and OD equal to the distance between the two girths. 
 It turns out that strips of the curvature shown in Figure 38 
 are suitable for all ordinary purposes, and we are spared 
 the labour of determining the curvature for each individual 
 tooth. 
 
 Fig. 49. 
 
 Fig. 50. 
 
 Fig. 50. a 
 
 Fir.. 51. 
 
 L. 
 
50 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 I proceed to describe how fusible metal may be used in 
 making a die for striking up crowns. 
 
 A split ferrule similar to that shown in Fig. 52 has one end 
 closed with a brass cap (Fig. 53) of a size to just close the 
 split of the ferrule, and is filled with composition which is 
 allowed to cool. The exposed end of the composition is again 
 warmed to the depth of about an eighth of an inch, and a 
 natural tooth of the size and kind required is wetted and 
 planted crown downwards into the centre of it (Fig. 53). 
 When the composition is again cool, the tooth is removed, 
 and the surface of the composition is polished with a file 
 and glass-paper, finishing with the back of the paper. The 
 tooth is then slightly warmed and replaced in the composi- 
 tion. A second ferrule (Fig. 52), split down one side to allow 
 of the ready removal of the cast presently to be made in it, 
 is heated and placed wide end downwards upon the composi- 
 tion so as to be co-axial with the tooth. A quantity of 
 fusible metal, melted in the brass cup (Fig. 48) standing in 
 boiling water, is poured into this ferrule and rapidly solidifies 
 about the tooth. 
 
 The dies thus obtained (Fig. 54) are all of one size, and 
 may, for convenience of handling, be inserted into the steel 
 punch (Fig. 55) made for the purpose. A mark should be 
 made with the excavator (Fig. 47) upon the side of the die 
 so that it may be kept in one position while in use. 
 
 These dies may be made somewhat more readily by filling 
 the first ferrule with moist clay instead of composition. The 
 clay needs no warming, and a smooth surface can be given to 
 it by merely passing a piece of glass over the end of the 
 ferrule. Much of the time spent in giving a polished surface 
 to the composition is thus saved, but the resulting die is 
 hardly of so finished a character. 
 
 To strike up a crown, all that is necessary is to wet a 
 piece of gold, place it upon bees-wax melted into and filling 
 the bottom of a vulcanite flask, and drive the gold into the 
 wax with a few blows of a mallet upon one of these dies. 
 The gold should be annealed three or four times during the 
 
SOME USES FOR FUSIBLE METAL. 
 
 .'I 
 
 process. The resulting plate should then be chased upon 
 the die by means of a steel punch so as to render the margin 
 more definite and facilitate the cutting away of the super- 
 fluous gold. The punch may be carried in a handle and used 
 
 Fig. 53. 
 
 Pie. 52. 
 
 
 as a pressure-punch (Fig. 56), and the die may be most 
 conveniently held during the chasing by taking a piece of 
 board about as thick as the die is deep, and making a hole 
 
 Pia. 56. 
 
 through it into which tho die will fit accurately (Fig. 57). 
 The hole passing quite through the board, the die may be 
 readily removed from it wh« n it- removal is desired, and may 
 be prevented from coming out during the chasing by placing 
 
 4—2 
 
52 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 the board upon the bench. Figure 58 is an illustration of 
 the crown obtained by the above process. It remains to cut 
 away the superfluous gold. 
 
 Fig. 57. 
 
 I may remark in passing that the use of spring-clamps 
 for holding a crown of this sort in position, when soldering it 
 to the collar, involves a risk of dragging the 
 work out of shape, and the object may be 
 attained much more readily without such 
 risk by the use of a pair of pliers and a 
 piece of binding wire, which should not be 
 twisted, but bent only, as shown in Figures 
 59 and 60. 
 
 Fig. 58. 
 
 The next use of the alloy is to form a model in pivoting. 
 An impression is taken in composition by means of the Dowel- 
 Crown appliances described on page 78, by which the direc- 
 
SOME USES FOR FUSIBLE METAL. 53 
 
 tion and depth of the canal are accurately determined ; and 
 a cast is taken in fusible metal. This 
 is done by softening and laying into j 
 the impression a thin sheet of wax, v U 
 wetting it, and filling up the impres- 
 sion above the wax with soft compo- 
 sition to form, as it were, a lid. The 
 wax is then removed and fusible metal 
 is poured in between the impression 
 and the lid through an opening ar- 
 ranged for the purpose. The wax piQ .^ piQ 6Q 
 should be so adjusted that as little 
 fusible metal as convenient may be used, as large masses of 
 the metal are apt to granulate in cooling. 
 
 The advantages of a cast obtained in this way over one 
 in plaster are that no time is lost in waiting for the cast to 
 set, and the more delicate parts of it, more especially the 
 reproduction of the root canal, are free from liability to injury 
 in working. 
 
 It must be admitted, however, that it is sometimes 
 difficult to obtain a satisfactory cast in this way ; and the 
 indestructibility of the root-canal, which is after all the chief 
 thing about the cast, can be more readily secured by a 
 method to be described later under Dowel-Crowns. 
 
 So much for the uses of fusible metal in crown- work. 
 We come next to the methods of using it in the repair of 
 vulcanite plates. 
 
 The first, it will be seen, is of great use in an emergency, 
 when a patient has had the misfortune to break out a 
 single tooth just before he is expected to make an impor- 
 tant public speech, or to take part in any of the many public 
 ceremonies in which to appear gap-toothed would be very 
 annoying. 
 
 In such a case, I cut a dovetail in the plate exactly as 
 one would cut it if one were going to vulcanise a tooth in ; 
 drill two small depressions, one in either edge of the dovetail; 
 secure the tooth temporarily from the front with shellac, 
 
54 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 and then melt some fusible metal into the dovetail with the 
 handle of the spade-shaped excavator (Fig. 47) made hot. 
 When in a molten state, the metal spheres much as mercury 
 does, and seems unlikely to make a proper fit ; but a slight 
 pressure between finger and thumb applied as the metal 
 cools puts matters right, and the expansion which takes 
 place on cooling gives a very tight and secure joint. The 
 whole thing may be done in about five minutes. Where an 
 additional tooth has to be inserted, the plate is prepared, 
 and the tooth is set up just as if it were to be vulcanised in. 
 
 Fig. 61. 
 
 Fig. 62. 
 
 Fig. 63. 
 
 It is then invested in plaster, the part where the rubber 
 would be packed being left exposed ; the wax is scalded out, 
 and fusible metal is poured in to take its place. 
 
 A second use for the metal in executing repairs arises 
 when the vulcanite base has been cracked and needs to 
 be strengthened with a small gold plate. In this case a wax 
 disc is applied to the vulcanite plate at the part to be 
 repaired, and a cast of this disc in fusible metal is obtained 
 by the same method as that described below for making a 
 trying-in plate (p. 55). This cast is set, face downwards, in 
 a layer of clay on the plate (A, Fig. 61); a ferrule of celluloid 
 similar to that shown in Fig. 52 is placed round the posts 
 
SOME USES FOR FUSIBLE METAL. 55 
 
 (Fig. 61); and fusible metal (A, Fig. 63) is poured in to unite 
 with and strengthen the previous cast (B, Fig. 63). The face 
 of the die thus obtained (Fig. 63) is then rubbed over with 
 rouge and water ; the die is placed, face upwards, between 
 the posts (Fig. 61); and a counterpart is cast by again put- 
 ting the celluloid ferrule about the posts and pouring fusible 
 metal slowly in till it reaches the tops of the posts. It is 
 advisable to smear a little clay between the celluloid ferrule 
 and the posts before making the casts. 
 
 To strike up the gold plate, we first place the washer 
 (Fig. 62) upon the plate (A, Fig. 61), then the die face 
 upwards, the gold plate, and the counter die (Fig. 63), in the 
 order named, the washer serving to raise clear of the posts 
 the end of the counter which is to be struck. During the 
 striking up, the posts should be supported by the fingers. 
 
 Lastly, there are the three ways in which the metal may 
 be employed in the manufacture of new plates. 
 
 First, as a base or trying-in plate. This is obtained 
 as follows : — A wax plate is fitted to the usual plaster model 
 and trimmed to the size of the desired metal plate. A piece 
 of wax, about three times as thick as the wax plate and half 
 an inch wide, is attached to the posterior edge of the plate 
 and carried along the centre line of the model to its extremity, 
 and this together with the whole plate, slightly French- 
 chalked, is enveloped, while in position on the model, in 
 a layer of composition about a quarter of an inch thick. 
 The composition being set, the wax plate is removed, and 
 fusible metal is poured in at the orifice left at the heel of 
 the model, between the model and the composition, to take 
 the place of the wax. 
 
 The metal plate thus obtained may in some cases be 
 difficult to remove from the model. In ordinary cases, it 
 may be removed with a little humouring, and it does not 
 really matter if the finer parts of the model are damaged in 
 the process, since the plate itself affords the quickest ami 
 most practical way of obtaining a duplicate model as good 
 as the original model was at first. 
 
56 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 In cases where the model is deeply undercut on the out- 
 side, owing to the form of the gum, the wax plate should not 
 be carried into the undercut, or it may be impossible, with- 
 out much trimming, to remove the metal plate from the 
 model. The latter plate, being removed, is trimmed, where 
 necessary, by going over it with a heated steel rod, such as 
 the handle of an excavator, and is then ready for the teeth. 
 
 With a little care a plate may be made in this way which 
 will fit the model, and the mouth too, far better than wax 
 can ever be made to fit them, all the rugae and other peculi- 
 arities being reproduced with wonderful distinctness. Such 
 a plate may be trusted not to change shape, and, when it 
 comes to flasking, the plate can be removed even more 
 readily than a wax one. Other advantages attend the use 
 of a plate of this kind. In the first place, the troublesome 
 necessity of making vulcanite trying-in plates is entirely got 
 rid of, and further, as there is no need to dry and dip the 
 models, the metal plate can be made and the bite obtained 
 in a comparatively short time after the impression has been 
 taken, thus saving a patient from a distance one at least of 
 the three journeys which are otherwise often necessary. 
 Lastly, as has been already explained in Chapter I. p. 12, a 
 plate of this kind makes it possible to save the original 
 model without any attendant disadvantage. 
 
 I may add that it is sometimes advisable to use 
 fusible metal to make lower as well as upper trying-in 
 plates, and this is particularly the case where there is likely 
 to be any difficulty in keeping the plate in position when 
 taking the bite, as there may be in some edentulous cases. 
 Otherwise, a lower made with composition is to be preferred, 
 as it is more readily made than a metal plate, and is less 
 likely to be distorted than a wax -plate. 
 
 Figure 64 shows a fusible metal upper and a composition 
 lower with the teeth waxed up, and a stay-bar (p. 14) applied, 
 in readiness for flasking. 
 
 A small partial plate made of fusible metal by the 
 
 above method has been found useful for actual wear in an 
 
SOME USES FOR FUSIBLE METAL. 
 
 57 
 
 emergency, when there has not been time to make a vulca- 
 nite plate. 
 
 A second and not less important use for fusible metal in 
 making new plates lies in employing it to make a slab 
 articulator. 
 
 Most people are no doubt familiar with the old slab-bite, 
 and probably most have discarded it for some of the modern 
 and more elaborate articulators. To some of the objections 
 to these I have already referred (p. 8), and I will only add here 
 that further difficulties arise from their use when a zinc is to 
 be cast. But the plaster slab has also its disadvantages, the 
 chief of which is the loss of time involved in drying and 
 
 Fig. 64. 
 
 (lipping the models and waiting for the slab to set. By the 
 use of metal instead of plaster this also may be got rid of. 
 
 To make a fusible metal slab, the models having been 
 so trimmed that the small tray (Fig. 65) will pass between 
 them when in the position given by the bite, this tray is so 
 adjusted about the post in the centre of the larger tray 
 (Fig. 66) that the models with the small tray between them 
 will sit comfortably in the larger tray. The small tray being 
 fixed in this position by means of the split tube and disc 
 (Fig. 67), fusible metal is melted in the larger tray by 
 placing it in a shallow pan of boiling water ; the boiling 
 water is then poured away and the models, held in the 
 position given by the bite, arc dipped into the molten metal 
 
58 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 and held there till the metal is cold, its cooling being accele- 
 rated by pouring cold water into the pan up to the level of 
 the edge of the tray. 
 
 Fig. 67. 
 
 This gives us a perforated metal slab (Figs. 68, 69) of the 
 same form as the old plaster slab, but the position of correct 
 articulation is much more sharply defined in the metal slab 
 
 Fig. 68. 
 
 than in the other ; the metal slab sets with great rapidity, 
 and, no drying or dipping of the models being necessary, 
 much time is saved. 
 
SOME USES FOR FUSIBLE METAL. 
 
 59 
 
 In cases where the upper plate is to be of gold, and the 
 lower of vulcanite, the upper model has to be shaped and 
 dried to facilitate the casting of the zinc. But the lower 
 model need not be dried, and can therefore be readily trimmed 
 so as to line with the upper model and enable the pair to sit 
 comfortably in the bite-tray (Fig. 66). 
 
 A word or two may be usefully said as to the method of 
 removing the slab from the trays. As the metal by 
 expanding when cooling takes a grip of the small tray, it is 
 
 Fig. 69. 
 
 necessary first to remove the split tube and disc, then to 
 clear the slab of the larger tray, and lastly to push out the 
 smaller tray from its centre. 
 
 The expansion of the metal must also be taken into 
 account when trimming the models, or it will be impossible 
 to remove them from the slab after it is set. Again, care 
 must be taken that the models are long enough to keep the 
 base-plate clear of the metal in the tray. 
 
CO OPERATIVE AND MECHANICAL DENTISTRY. 
 
 With these simple precautions everything will go 
 smoothly, and a good slab will be obtained in a very few 
 minutes. 
 
 Another use for fusible metal lies in filling up the 
 interstices between tube-teeth in a gold bar lower, 
 
 the purpose, of course, being the prevention of accumulations 
 between the teeth. 
 
 This is done by placing composition along the outer sides 
 of the teeth and pouring fusible metal into the interstices on 
 the inner side. The composition being removed, the metal 
 may be trimmed with a warm rod and finished in the usual 
 way. 
 
 Advantage will also be found in employing the metal to 
 make a model for correcting a metal plate which has 
 been accidentally bent ; and again, to give the articula- 
 tion when setting up teeth for a case where all the teeth in 
 the other jaw are still standing. In this last case, however, 
 it is not easy to get a cast in which the teeth are as definite 
 as in a plaster model, though, if a good metal cast be once 
 obtained, the freedom of the teeth on it from liability to 
 abrasion or other injury is a great advantage. 
 
 Lastly, as Mr Fenn Cole of Ipswich pointed out, a fusible 
 metal plate may be useful as a splint in the case of a 
 fractured jaw. The shortness of the time in which such a 
 splint can be prepared is a very great advantage, relieving 
 the patient of hours of pain, and enabling full advantage to 
 be taken of the tendency to heal by first intention. 
 
 While on the subject of splints, I may point out that a 
 fusible metal or a vulcanite splint may be secured in 
 position, when sufficient teeth are standing, by drilling holes 
 through the plate in two places in such a way that tapering 
 wires passing through them will pass between adjacent teeth 
 and hold the plate down. 
 
 Of course, in making such a splint, the crowns of all the 
 teeth should be allowed to come through and antagonize 
 with the uppers. 
 
SOME USES FOR FUSIBLE METAL. 61 
 
 It is to be regretted that surgeons in general do not seem 
 sufficiently aware of the advantage to be derived from 
 sending early for a dentist in a case of fractured jaw, and 
 from calling one in beforehand when an operation for 
 epithelioma is to be performed. 
 
CHAPTER IV. 
 
 MATRICES : HOW TO MAKE THEM AND HOW TO APPLY 
 THEM. 
 
 The following is an extract from a paper read at the 
 Annual Meeting of the British Dental Association at New- 
 castle in the spring of 1894. 
 
 " When the meeting of the Association was last held in 
 London (1891), in the course of a paper which I had the 
 honour of presenting to you on fusible metal, I described 
 incidentally a method of making a matrix for one of the 
 purposes I then had in view. The form of the matrix then 
 described was obviously one capable of much wider applica- 
 tion, but, as I had been used to it from my earliest years as 
 a dentist, I did not then think it necessary to dwell upon it. 
 
 Observing, however, that the several depots continue to 
 advertise matrices of an almost endless variety of form, 
 among which this particular form never occurs, I have come 
 to the conclusion that it will be useful to insist a little more 
 strongly on the advantages attending the form of matrix I 
 am about to advocate. 
 
 I have in my hand a large model of an upper bicuspid to 
 which I have applied a band in the form we would all like a 
 matrix to take when applied to an actual tooth (Fig. 70). 
 This band I will now remove and flatten out, so that we may 
 see what form such a band takes when so treated. It will be 
 interesting to compare it (Fig. 71) with the forms advertised, 
 and I have had a few of the latter (Fig. 72) drawn on this 
 sheet for the purpose of comparison. You will see that what 
 
MATRICES: HOW TO MAKE AND HOW TO APPLY THEM. 63 
 
64 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 I think I may now call the correct form (Fig. 71) is practi- 
 cally a portion of a flat ring, such as this (Fig. 73), and there 
 will be no difficulty, I think, in showing that this is what we 
 might expect. 
 
 The general resemblance between the tooth-model (Fig. 
 70) and the cone I have here (Fig. 74) is obvious, and the 
 resemblance of the portion of the cone I have shaded to the 
 matrix upon the tooth is not less so. Now it is clear that 
 the distance of every point in the edge of the cone from the 
 apex is the same, so that when the cone is opened out (Fig. 
 75), the edge must open out into a circle with the apex as 
 centre, and the shaded portion must open out into a flat ring, 
 which proves the proposition. 
 
 Having now decided that the correct form, may I say, of 
 a matrix is a portion of a flat ring, it remains to show how to 
 obtain such a ring to fit any given tooth, and the method is 
 fortunately very simple, and what is still more fortunate, I 
 suspect you will say, is that we need not individually bother 
 our heads about it. It turns out practically that all teeth, 
 whether molars or bicuspids, require parts of the same ring, 
 the only difference being in the length of the part required. 
 Using the simple method I have referred to, I have ascer- 
 tained the radius of the required ring, and have prepared 
 matrices of three sizes (Fig. 76), such as can be readily repro- 
 duced, and are in practice pretty well all that will ever be 
 required. Perhaps you will allow me briefly to describe how 
 I ascertained the radius of the ring. The method will be 
 useful to meet special cases. 
 
 Taking the girth of a tooth at its greatest circumference, 
 and also at the gum margin, I set these out on a straight 
 line, starting from the same point (Fig. 77). OA repre- 
 sents the girth at the gum margin, OB the greatest girth. 
 At and A, I set up perpendiculars OG and AD. I made 
 AD and OE equal to the depth of the desired matrix, and, 
 joining BD, produced it to meet OG in G. The point G is 
 the centre from which, with radii GO and CE, circles can be 
 described which will give the desired ring. 
 
 With the proof of this I need not trouble you, but one 
 
MATRICES: HOW TO MAKE AND HOW TO APPLY THEM. 65 
 
 other point with regard to the form of the matrix remains to 
 be noticed, and that is, the form of the ends which are to 
 come together when the portion of a flat ring which we have 
 now obtained is bent up to form the matrix, which is itself, 
 as we have seen, practically a portion of a conical surface 
 (Fig. 70). 
 
 Returning for a moment to our cone, we see that the 
 meeting edges are straight lines running through the apex of 
 the cone, so that these straight lines, when the cone is opened 
 out (Fig. 75), are radii of the circles which give us the flat 
 ring. If, then, the portion of a flat ring (Fig. 71), when bent 
 up, is to give us a matrix of the desired conical shape (Fig. 
 70), its ends must be radii of the circles forming the ring. 
 
 I come now to the method of applying such a matrix to 
 a tooth, and I have endeavoured to devise a clamp which 
 should meet requirements — with what success I must leave 
 you to judge. This clamp, or double-acting parallel vice 
 (Fig. 78), which is the result of my endeavours, and which I 
 have now the honour to introduce to your notice, requires 
 some additions to the portion of a ring, which constitutes 
 the matrix proper, for the purpose of securing the matrix to 
 the clamp. I will call these additional portions ' lugs.' With 
 these additions the strip to form the matrix takes this final 
 shape (Figs. 76, 79). In applying a matrix to a clamp, the 
 ends of the strip are to be inserted one after the other into 
 the slots (Fig. 78) provided for the purpose in the clamp, and 
 bent up along the radial lines before described, each strip 
 having one or two such radial lines (Fig. 76) marked upon 
 each end to ensure its being bent in the right direction. The 
 ptirpose of having more than one mark at each end is to allow 
 of the ready adjustment of the length to the particular tooth 
 to be dealt with. For tightening the clamp we need a 
 flexible key such as this (Fig. 80). 
 
 I find I am running into rather more time than I 
 anticipated, but there are still one or two more rather im- 
 portant points which, with your kind permission, I should 
 like to touch upon. 
 
 We often find it recommended that, when a matrix is 
 L. 
 
66 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 applied to a tooth, its lower margin should be forced up into 
 close contact with the tooth by means of a wedge. This is, 
 of course, impossible when there is no adjacent tooth to 
 wedge against, and when the cavity extends beyond the gum 
 margin ; but I hope to show that it is equally impossible in 
 many cases, even when there is an adjacent tooth, and when 
 the cavity does not extend beyond the gum margin. 
 
 Every one is aware of the grooves generally to be found 
 running down the sides of a root, especially the sides of 
 upper bicuspids, and will recognise at once the impossibility 
 of forcing the matrix into such a groove by means of a wedge. 
 I have had my model made in sections so as to be able to 
 illustrate this difficulty, and have but to apply this rod, 
 representing a wedge, to the section (Fig. 81) to make my 
 meaning clear. Some method of meeting this difficulty is 
 desirable, and I venture to propose this. 
 
 I have had made a mandrel or shaping-tool (Fig. 82) in 
 the form of a double cone, one end corresponding to the cone 
 formed by a matrix for an average molar, and the other by a 
 matrix for an average bicuspid. This is in practice all that 
 is required. Down the sides of the mandrel I have had 
 grooves cut to correspond to the grooves in teeth. This is 
 how I use the mandrel. The ' lugs ' of a matrix having 
 been inserted into the slots in a clamp, I slip the matrix on 
 to a mandrel, and with a hammer tap it into a symmetrical 
 shape (Fig. 79). If the matrix be now withdrawn from the 
 mandrel, it will be found securely fixed into the clamp, and 
 capable of being carried any distance to the mouth without 
 risk of its falling out. But before withdrawing the matrix 
 from the mandrel, I force its lower margin into the groove in 
 the mandrel. On applying a matrix so bent to a tooth, I find 
 that the bent portion forces itself into the groove in the 
 tooth, should one exist, and is not drawn out when the clamp 
 is screwed up ; whereas, should no groove happen to exist in 
 the tooth, the bent portion of the matrix is drawn out, and 
 the matrix in any case takes accurately the form of the root to 
 which it is applied. Moreover, owing to its conical shape, the 
 matrix, on being clamped up, naturally works its way under 
 
MATRICES : HOW TO MAKE AND HOW TO APPLY THEM. G7 
 
 Fig. 78. 
 
 r-? 
 
 Fig. 82. 
 
 Fig. 80. 
 
 Fig. 79. 
 
 Fig. 83. 
 
 5—2 
 
68 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 the gum, and this process may be promoted, if desired, by 
 trimming the lugs. The matrix once in position, the compact- 
 ness of the clamp allows the rubber-dam to be applied almost 
 as readily as to the teeth alone, and the presence of the clamp 
 is afterwards a positive advantage to the operator by keeping 
 away the rubber-dam, and so affording him a clear view of 
 his work. I may suggest that in applying the rubber it 
 should be put first over the clamp and then over the tooth. 
 
 The last point to which I wish to call attention is the 
 removal of such a matrix, and here I would urge that it is 
 always best to leave a matrix on, at any rate for a few hours, 
 after an amalgam filling is put in. Indeed, it is sometimes 
 impossible to remove a matrix, fitting as I have described, 
 without disturbing the filling. I have, therefore, to suggest 
 an easy method of securing a matrix in position as long as 
 may be desired. With the instrument I have here (Fig. 83), 
 I carry a loop of thin wire over the clamp and behind the 
 lugs of the matrix, and, holding the instrument so as to close 
 the loop lengthwise of the tooth, I twist the ends of the wire 
 together by a few turns of the carrier, partly remove the 
 clamp, give a few final turns to the wire, cut off what is 
 superfluous, press the lugs to the tooth, and the matrix is 
 fixed. To remove it, we have simply to draw the lugs 
 together and slip off the loop, and this can be done by the 
 patient." 
 
 To this in the summer of 1894 when addressing a meet- 
 ing of the Irish Branch of the Association I was able to 
 add the following : " I should like to say a few words with 
 regard to a class of cases in practice which have hitherto 
 given my partner and, I have no doubt, others some trouble, 
 and have been a source of no little pain to patients, but for 
 which a remedy has lately presented itself. I refer to those 
 troublesome cases in which the gum has crept into a 
 cavity and covers an otherwise exposed pulp. I need not take 
 up time by describing how we have hitherto dealt with such 
 cases, but will proceed at once to describe our new method. 
 It is very simple. We take one of the matrices I had the 
 
MATRICES : HOW TO MAKE AND HOW TO APPLY THEM. G9 
 
 honour to describe to the General Meeting of the Association 
 at Newcastle, and, having carbolised the gum, we apply the 
 matrix to the tooth. The form of the matrix is such that 
 it conforms to the shape of the tooth from the moment the 
 edge first presented to the tooth has passed the crown. It 
 follows that when the matrix is tightened up by means of 
 the clamp, it works its way along the tooth and strangulates 
 the intrusive portion of gum, practically cutting it off, 
 without, however, any discharge of blood. The portion of 
 gum filling the cavity can then be removed, and all this 
 without pain to the patient. The matrices are gilded and 
 can therefore be left on without ill effect, thus enabling the 
 operator to apply his dressing for the devitalisation of the 
 pulp and to secure it in position by means of any of the 
 temporary fillings." 
 
 A word or two must be added about the clamp and 
 the method of putting one together. Experience has 
 shown that it is necessary to warn those who may use 
 these clamps that they are furnished with a double screw 
 
 Fig. 84. 
 
 (Fig. 84), the screw at the screw-head or square end being 
 left-handed, that at the other right-handed. One conse- 
 quence of this is that, if taken to pieces the instruments are 
 puzzling to put together again, and some who have essayed 
 putting them together have ruined the clamp by trying to 
 force an end of the screw into a chop for which it was not 
 intended, thereby breaking up the threads. 
 
 A few hints may save this trouble. Begin by remo\ ing 
 the slide-bar, if not already removed, from the chop into 
 which it is screwed. Then, using the screw-head in the 
 ordinary way. that is, by giving it turns clockwise from left 
 to right, screw the opposite end into the flat side of the 
 chop in which the slide-bar was originally fixed, until the 
 chop reaches the middle of the screw, where it will stop 
 
70 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 naturally, if no violence be used. Then slip the other chop, 
 flat-side foremost over the screw-head and spin it round the 
 screw counter-clockwise from right to left. When the two 
 chops have met, flat sides together, in the middle of the 
 screw, pass the slide-bar through the chop nearest to the 
 screw-head and screw it in the ordinary way into the other. 
 The clamp will then be ready for use. 
 
 In no case whatever should a screw be forced through 
 a chop, since when chops aud screws are brought together 
 in the right way, everything works with the greatest ease. 
 
 There are also one or two hints with regard to the 
 matrix which may be useful. 
 
 The first of these is that, while something is to be 
 gained by trimming the lugs of the matrix, as already 
 explained, it is futile, as well as needless, to cut them so that 
 there is a large prominence on the shorter margin of the 
 matrix in order to meet the case of a deep cervical cavity. 
 Such a prominence escapes the strain exerted by the clamp 
 when tightened, and consequently curls away from the tooth, 
 thereby allowing the tilling to be pushed through and 
 sacrificing the effect for which the matrix is designed. It 
 should be remembered that the matrix naturally works its 
 way along the tooth as the clamp is tightened. When this 
 has to be carried to an extent which causes pain in the gum, 
 some relief may be afforded without seriously affecting the 
 utility of the matrix by slightly straightening the lower 
 margin, that is, by cutting off a strip, narrow near the 
 ' lugs ' and narrowing off to nothing before the middle of 
 the matrix is reached. This may be done at one or both 
 ends of the matrix. 
 
 When a difficulty arises in putting on a matrix between 
 closely adjacent teeth, room may be secured by forcing 
 a piece of hard steel tape, rather thicker than the matrix 
 to be used, between the teeth and leaving it there for a 
 minute or two. 
 
 Again, deep cervical cavities are sometimes difficult 
 to prepare -without wounding the gum. In such cases 
 
matrices: how to make and how to apply them. 71 
 
 a matrix may be loosely applied before beginning to work 
 at the deepest part of the cavity, and it will then be 
 impossible to damage the gum during the work. 
 
 These hints are the outcome of my partner's experience 
 iu the use of the matrix ; and to him is also due, as I 
 gladly take this opportunity of acknowledging, the stimulus 
 that has led me to attempt much that is here recorded. 
 
CHAPTER V. 
 
 CROWN AND BRIDGEWORK. 
 
 Some seven years have now elapsed since, at the meeting 
 of the Association at Exeter, I ventured to take part in what 
 was, I fear, an abortive discussion upon this subject, abortive 
 because almost entirely devoid of those statistics which alone 
 could enable us to form a judgment as to the utility of the 
 many fantastic devices put forward in the text-books under 
 the name of Bridgework. Dr Melotte did indeed on that 
 occasion talk of two successes, one of seven years' standing 
 and another of four, but also spoke of many mishaps with his 
 bridges ; while Dr Barrett supplied a stream of cold water. 
 
 At that time I had had but little practical experience of 
 bridgework, and I have had none since, nor shall I ever have 
 any, until some of its enthusiastic advocates are good enough 
 to show me not merely how a bridge may be applied in any 
 given case — anyone of a fairly mechanical turn of mind could 
 do that abundantly; it is done to excess already in some of 
 the text-books, — but also that the bridges so applied have 
 any life worth considering before them, and are really bene- 
 ficial and not harmful to the patient. 
 
 A priori reasoning is certainly all against bridgework, of 
 which the fundamental concern is how to make one or two 
 roots do the work of three or more ; how to make an instru- 
 ment, which is by nature intended to endure in the main a 
 longitudinal pressure, endure an unnatural lateral thrust or 
 drag. In the most favourable case, this does but affect roots 
 
CROWN AND BRIDGEWORK. 73 
 
 which would iu any event have to be crowned, and the 
 damage, which in my belief always results, sooner rather 
 than later, only amounts in this case to the loss of such roots. 
 But in many cases, if we are to credit what we read, natural 
 crowns, which could with a little filling be readily made good 
 and so remain useful for years, have the lugs of a bridge 
 embedded in their fillings, and forthwith the trouble begins. 
 If, in spite of a stress upon it which it is ill-calculated to 
 withstand, the filling holds its ground, there ensues, under 
 the pressure of mastication, a thrust or drag upon the root 
 and its socket for which they were never intended, and with 
 a result that need not be described. If, on the other hand, 
 as is more likely, the filling gives way, decay is renewed in 
 the tooth, and in either case the end is the same, the loss 
 not only of the bridge but also of the tooth. 
 
 In the worst case of all, a sound natural tooth is hacked 
 to receive a lug, or trimmed out of all recognition to receive 
 a cap upon which to fasten a contrivance in its nature 
 destined to create unrest and destruction. It is an axiom 
 with builders that an arch never sleeps. 
 
 All this is avowedly but a priori reasoning, and experience 
 may, of course, have proved it, as it so often does prove such 
 reasoning, utterly unfounded, but, if it has done so, we may 
 reasonably ask those who have had the experience to demon- 
 strate it to us by giving us a full account as well of their 
 failures as of their successes, so that by comparing the one 
 with the other we may be able to judge of the probability 
 that the like success is possible for us. Meanwhile I am 
 satisfied that I can do better for my patients with a plate 
 than with the least ambitious piece of bridgework. 
 
 But having called thus loudly for statistics, it is right 
 that I should contribute such as I can. At Brighton in 
 LS89, my partner and I demonstrated a method of inserting 
 a bridge supplying the four upper incisors and supported 
 upon the two lateral roots. The method was far from being 
 as simple as with the appliances I now possess it might 
 readily be made, and I should not adopt that method again. 
 Subsequently we inserted an exactly similar bridge on the 
 
74 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 same plan. The second bridge after six months' wear was 
 knocked out by the handle of a mangle and is therefore only 
 interesting, from the statistical point of view, in this, that the 
 patient declared she liked the bridge and was sorry to lose it. 
 But the first bridge failed, and failed not, I venture to say, 
 from the method of insertion, but from the nature of the 
 case. For the failure arose from a movement of the roots, 
 whereby the bridge was made to protrude. In other words, 
 the two roots failed to support a lateral strain which was 
 properly the work of four. No one will suppose for a moment 
 that we were foolish enough to bring this abuut by allowing 
 the lower teeth to strike the bridge, but it may perhaps be 
 urged that wires passing from the bridge round the canines 
 would have called in the aid of two additional roots, to which 
 I can only reply that it w r ould but have delayed the result 
 while extending the area of the mischief. We have since 
 seen a bridge, the work of others, fail in precisely the same 
 way. It is needless to say that we do not now advocate the 
 application of a bridge in such a position, whether on the 
 plan then described or any other, and yet here, if anywhere, 
 one would have said most was to be hoped from a bridge. 
 
 But if bridgework is, as I think, in such dubious case, it 
 is quite otherwise with Crown-work, by which many a 
 feeble root, which awhile ago would have been regarded as 
 past hope, is now saved and made useful for years. But, 
 while the utility of crown-work is beyond dispute, the prin- 
 ciples upon which it should be carried out are much discussed, 
 and the methods actually adopted are of almost endless 
 variety. This is, no doubt, partly because individual cases 
 suggest and even demand special treatment, but more espe- 
 cially because there is so little opportunity of comparing the 
 actual working and results of the several methods advocated. 
 
 In these circumstances, I will venture in the first place 
 to make a few remarks upon such of the methods and 
 systems of crowning as are known to me, and then pro- 
 ceed to describe the plans which my partner and myself, 
 
CROWN AND BRIDGEWORK. 75 
 
 while prepared at all times to admit variations to meet 
 individual cases, now generally pursue. 
 
 Among the devices which appear to me quite unnecessary 
 is that of the feathered post, intended to prevent the 
 possible rotation of the crown. Any device which calls for 
 a considerable enlargement of the canal is proportionately 
 objectionable, and the risk of rotation is obviated, without 
 any enlargement, by simply cutting down the anterior edge 
 of the root somewhat farther than the posterior edge, so that 
 the surface of the root in contact with the crown is not strictly 
 plane. If this be done, so long as the post is fixed longitu- 
 dinally, rotation is impossible ; while, if the post becomes 
 loose, the result is a failure, whether the post be feathered 
 or not. 
 
 Another method which I never adopt is that with a tube 
 and a split pin, and this for the reason that, the split pin 
 being removable, foreign matter finds it way into the tube, 
 decomposes, and becomes offensive. 
 
 Of the systems familiar to us by name, the Bonwill is 
 faulty in that it leaves an opening by which the cement with 
 which the crown is fixed is exposed to the fluids of the 
 mouth, and, moreover, the amount of grinding of which the 
 fiown admits is strictly limited and the crown is, therefore, 
 not applicable in shallow bites. 
 
 The Logan, having a fixed post, admits of but little 
 grinding and shortening, and therefore necessitates the 
 possession of a large stock to meet the variety of cases or 
 compels the undue shortening of the root. Moreover, again 
 because the post is fixed in the crown, the root must be 
 'thimbled' out to receive it; cement must be used; the crown 
 is consequently all but irremovable, and in the event of a 
 fracture the rout is lost. Moreover to stand the firing which 
 is necessary when baking the tooth, the post must be made 
 of some hard platinum alloy, a costly material which is quite 
 uncalled for when the post is fixed in the crown after the 
 crown has been ground to the root. 
 
76 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 The banded Logan adds to these disadvantages the 
 faults of a Richmond and moreover it shows the gold. 
 
 In a Richmond crown, the band determines the direc- 
 tion in which the crown and therefore the post fixed in it 
 must move when being applied to the root, and the canal 
 must therefore be reamed out to admit the post in the 
 direction fixed by the band. 
 
 The Biittner method carries all the faults of the 
 Richmond to extremes, involving the cutting up of tooth 
 substance to an extent that is never justifiable and is often 
 impossible, and leaving besides some of the cut surface 
 exposed. 
 
 Before going on to describe the general practice of my 
 partner and myself in crowning, I may mention that 
 we have found advantage in the case of very feeble 
 anterior roots in simply capping and banding them with 
 gold, using no post, but trusting wholly and successfully to 
 cement and to accuracy in fitting the band to a model 
 obtained as hereafter described. In another case, my partner 
 having built up a very poor bicuspid root with amalgam, 
 I made a cap and band upon which I mounted a tube-tooth, 
 and again fixed the crown on the root without the use of a 
 post, trusting as before to accuracy of fit. 
 
 Lastly, I may refer those who are interested in the his- 
 tory of such matters to page 495 of the Journal of the 
 British Dental Association for 1889 and to page 475 of that 
 for 1890, where they will find accounts of the methods which 
 I then pursued, but which I merely mention here in order 
 formally to discard them, having superseded them, I hope 
 rightly, by the methods presently to be described. Amid all 
 changes, however, I have always endeavoured to be faithful 
 to one aim, and that is to avoid working at the mouth, when- 
 ever possible. One result of this is the paper which imme- 
 diately follows, and which was read at the Annual Meeting 
 of the Association at Edinburgh in 1895. 
 
crown and bridge work. 77 
 
 "On a Method of obtaining a Plaster Model as good 
 as the Mouth with a view to Crowning one or 
 more of the Anterior Teeth. 
 
 I have at all times been anxious, as I have no doubt 
 everyone, whether practitioner or patient, has been anxious, 
 that the work to be done at the mouth should be reduced to 
 a minimum, and I wish now to explain a method whereby 
 this is, I think, attained in cases where one or more 
 anterior teeth are to be crowned. 
 
 What has hitherto induced many to work entirely at the 
 mouth in crowning has been the difficulty, if not the 
 impossibility, of getting a definite impression of the root-face 
 by the ordinary means. The distance between the neigh- 
 bouring teeth at the gum margin being greater than that 
 between them at their cutting edges, there is always a 
 certain amount of dragging which obliterates the impression 
 of the root-face. 
 
 This difficulty I am now prepared to meet by a method 
 which, besides furnishing definite impressions of the root- 
 faces, will give in the same impression the height of the 
 neighbouring teeth, natural or artificial, the different direc- 
 tions of any number of root canals, and as many metal-lined 
 canals in the model, the metal being intended to render the 
 canals incapable of injury in the process of fitting the posts. 
 
 To-morrow my partner and I propose to demonstrate this 
 method upon a living but, save for the purpose of crowning, 
 a useless tooth. I will here briefly describe how we shall 
 proceed. We shall first remove the crown by means of a saw 
 — and I should like to take this opportunity of remarking 
 that the excising forceps ought to be regarded in cases of 
 crowning as the key now is in cases of extraction. Having 
 removed the pulp and sealed the apex of the root, we trim 
 the root-face to a convex form by cutting down the edges all 
 round, and open up the root-canal for the post. At this 
 point we find it most convenient to take the depth of the 
 canal with a post and slide or root-sound (Fig. 85), which can 
 then be laid aside for after use. We next proceed to take the 
 
78 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 impression, and I have now to introduce my first novelty in 
 the shape of a small cap of this form (Fig. 86). This cap we fill 
 with composition, pass a post (Fig-. 87) through the middle, 
 
 
 Fig. 85. 
 
 Fig. 86. 
 
 Fig. 87. 
 
 and cool. Then heating the surface only, which has been 
 shaped into a mound about the post, as here 
 shown (Fig. 88), we apply it to the root-face, first 
 passing the post into the canal. The effect of 
 the cap and of the mounded form of the compo- 
 sition is to force away the gum from the root-face 
 and give a sharp impression inside the cap, which 
 may be almost instantly cooled by means of a 
 syringeful of cold water. We now remove the 
 cap and post, trim off the composition which is 
 outside the cap, replace the post and cap on the root, and, 
 having wetted the neighbouring teeth, take an impression 
 with my second novelty — a tray with a slot running round 
 the bottom at its outer edge (as shown in Fig. 89 or 
 Fig. 90). In doing this the post is made to strike the centre 
 of the composition, and is directed towards the front of the 
 tray, which then guides it through the slot. We now cool 
 the impression with a syringe as before — it can be done 
 in a minute — remove the post and then the impression. 
 The cap is found sitting in the impression, the edge of the 
 metal only being visible. We are now ready to cast the 
 model. We replace the post and fix it with wax applied to 
 
CROWN AND BIUDGEWORK. 
 
 79 
 
 the tray, having first fitted on the end of the post which is 
 to enter the cast a short, roughened, copper tube with an 
 open seam (see Fig. 91). When the model is cast and the 
 
 Fig. 89. 
 
 post withdrawn, this tube is left behind in the model, and 
 forms the indestructible root-canal before referred to (shown 
 at A, Fig. 92). The model is, of course, dried and dipped in 
 stearine. 
 
 Fig. 90. 
 
 This, gentlemen, completes the description I wished to 
 offer you. You will have seen that the small cap not only 
 
80 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 secures a sharp impression of the root-face, but preserves it 
 from all risk of dragging, while the slot in the tray, if this be 
 properly chosen for the arch, will admit any number of posts 
 
 Fig. 91. 
 
 at the same time (Fig. 93), and this, too, even in the process 
 of taking an impression for a full upper. 
 
 I may add that, although it must be rare to find, and 
 often ruinous to make, the canals of two roots parallel, it is 
 
 Fig. 92. 
 
 Fig. 93. 
 
 easy, with such a model as I have described, to make parallel 
 the projecting portions of the posts inserted in the roots, 
 and the advantages of such posts for securing plates and 
 bridges are obvious." 
 
 The demonstration promised in this paper was not 
 actually given, for the want of a patient, until the Annual 
 Meeting of the Association in London last year (1806). 
 
CROWN AND BRIDOEWORK. 81 
 
 A brief description of what was then done will illus- 
 trate our general practice. The patient, in the particular 
 case dealt with, was a female, and the tooth was a right 
 upper central. With a saw arranged to cut at right angles 
 to the frame (Fig. 19, p. 31), the crown was cut off level with 
 the gum, the saw blade being kept cool the while by means of 
 water from a syringe. The pulp, whilst still deadened by 
 the action of the saw and the cold water, was immediately 
 extracted by thrusting a Donaldson bristle, previously 
 standing point downwards in carbolic acid, into the canal, 
 twisting it round, and withdrawing it with the pulp ad- 
 hering. This reads like an operation calculated to give great 
 pain, but proves otherwise in practice, the patient in the case 
 described not flinching at all. There was a little blood, 
 which was carefully washed out ; the canal was dried with 
 hot air and finally by a hot platinum wire ; the apex was 
 sealed with chloro-percha on a shred of cotton-wool carried 
 to the apex on the point of a cleanser and followed by a 
 gutta-percha point ; the root-face was trimmed to a convex 
 form, the anterior edge being cut away to just beyond the 
 gum margin, and the canal was drilled for the post. An 
 impression of the root-face was then taken with the appli- 
 ances above described (pp. 77 — 80) and a dowel-crown was 
 fitted by the method given below. 
 
 Whatever objection may be imagined against the 
 removal of the crown of a living tooth in the manner 
 above described — and a little reflection should convince 
 objectors that the tax upon the patient owing to anticipation, 
 pain, and shock by a method so brief and unlooked for, as 
 compared with that arising from more prolonged operations 
 often necessarily borne without an anaesthetic, is really 
 insignificant — no such objection can be raised against 
 the removal by sawing of the crown of a tooth in 
 which the pulp is dead, and a very decided advantage is 
 to be gained by so removing it, as will be seen from what 
 follows. 
 
 In preparing a septic tooth for crowning, we cut off 
 the crown with a saw ; clear out the canal with a Donaldson 
 L. 6 
 
82 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 bristle and cotton-wool ; wash with peroxide of hydrogen ; 
 dry the canal, and leave in it a pledget of non-absorbent 
 cotton-wool, moistened with formalin and afterwards squeezed 
 nearly dry in a napkin. We then remove the decay from 
 the severed crown ; insert a piece of wire as a post, fixing it 
 in the crown with cement, and at the same time filling any 
 cavity there may be ; put ' temporary ' gutta-percha round 
 the post, and force the crown home upon the root while the 
 gutta-percha is still soft. 
 
 With the crown thus restored, the patient is free from 
 the disfigurement due to the want of an anterior tooth, 
 and can afford to wait until the operator is satisfied that the 
 root is in a fit condition for permanent treatment, a great 
 advantage, ready access to the root being a highly important 
 factor in the successful treatment of septic teeth. 
 
 TO APPLY A DOWEL-CROWN. 
 
 Having obtained a model in the way described above 
 (pp. 77 — SO), and decided, say, that it is a case for a plate- 
 tooth, I take a piece of 22 carat gold (Ash's No. 4) and 
 burnish it down upon the surface of the cast of the root to 
 form a cap; fit a post of 18 carat gold to the canal in the 
 model and solder cap and post together. Next, I grind a 
 plate-tooth to fit the cap ; back it with 18 carat gold for 
 the sake of its greater hardness compared with 22 carat ; 
 solder the tooth to the back without investing (pp. 22, 23), 
 and the back to the cap ; finally strengthen the cap by 
 flowing solder over it, and the crown is ready for the mouth. 
 
 In cases where there is room for an all-porcelain 
 crown, I have hitherto used Ash's ordinary tube-teeth, but 
 the Firm have now kindly undertaken, at my suggestion, to 
 revive a form of tooth (Fig. 94) which they used to make some 
 fifty years ago, and of which a specimen has been to my 
 knowledge in the possession of myself and of my predecessors 
 in practice for upwards of thirty years. This is a tube- 
 tooth with the canal directed towards its cutting edge 
 but not penetrating to the surface, in this resembling 
 
CROWN AND BRIDGEWORK. 
 
 83 
 
 the recently introduced Newland Pedley crown and certain 
 forms advertised somewhat earlier than that crown in some 
 of the American Journals. The advantage of this form of 
 crown over ordinary tube-teeth is that the canal, following 
 more correctly the line of the canal in the natural tooth, 
 does not necessitate so large a bend, if any, in the post. The 
 post not being fixed in the crown, as in the Logan, the crown 
 can be ground and fitted to the root. To facilitate this and 
 
 Fig. 94. 
 
 save some of the labour involved, the base of the new crown 
 (Fig. 94) will differ somewhat from that of fifty years ago, 
 and, to admit of a thicker and stronger post than one of pin 
 size wire being used, the tube will be a little larger than in 
 the present tube-teeth. 
 
 Having selected a suitable crown of this kind or an 
 ordinary tube-tooth, I grind it to fit the root, and, to protect 
 the plaster model while doing so, I place a strip of thin 
 articulating paper over the root and oil the exposed surface, 
 making a hole in the paper for the post by means of the 
 Ainsworth Rubber-Dam Punch. Then, taking advantage of 
 the metal-lined canal in the model, I bend the post, which 
 may be of hard-drawn dental alloy, so as to give the tooth 
 its proper alignment, and solder the post into the crown by 
 the method described on page 23. 
 
 It is advisable that the part of the post which goes 
 into the root should be somewhat thicker than that which 
 goes into the crown, so that there may be ;i shoulder at the 
 junction against which the crown may press when the post is 
 being forced into the root. 
 
 In fixing either of these crowns in the root I put 
 silk and mastic on the post and a small disc of base-plate 
 
 6—2 
 
84 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 gutta-percha between the crown and the surface of the 
 root, proceeding as follows: — The crown being ready to 
 leave the workshop, the disc of base-plate gutta-percha is 
 
 Fig. 95. 
 
 applied to the base of the crown, the post passing through it. 
 
 Then, a light copper tube (Fig. 95) being used as a holder, 
 the crown and gutta-percha are heated to 
 make the latter adhere. While the gutta- 
 percha is still soft, the crown is pressed home 
 on the natural root and, when the gutta- 
 percha is set, the crown is withdrawn, and 
 the gutta-percha trimmed with a sharp knife ; 
 the root is dried ; silk is applied to the post 
 and the crown is again tried in the mouth to 
 test the sufficiency of the silk. Thick mastic 
 is then smeared on the silk, and the crown 
 with the help of a crown setter (Fig. 90) is 
 finally driven home. 
 
 I may point out that in the event of frac- 
 ture a crown so fixed can be removed at 
 will without risk of disturbing the root ; 
 whereas, if cement be used, as it must be 
 where the canal is much enlarged, this cannot 
 be done, and consequently a fracture of the 
 crown probably means the loss of the root. It 
 will be seen too that, the exact position and di- 
 rection of the canal being faithfully reproduced 
 in the model, the post can be so accurately 
 placed that no enlarging of the root-canal 
 is called for beyond what is necessitated by 
 the oval form which the canal shows in section 
 when the crown is cut off. If a post were 
 used which fitted the shorter diameter of this 
 oval, spaces would be left between the post 
 Fig. 96. and the extremities of the longer diameter of 
 
CROWN AND BRIDGEWORK. 85 
 
 the oval into which foreign matters would insinuate them- 
 selves and destroy the root. Moreover, the post would have 
 room to move. It is necessary, therefore, to make the section 
 of the canal a circle with the greatest width of the oval as 
 diameter. But this is absolutely the only enlargement called 
 for, unless it be necessary to remove decay. 
 
 These methods of making and fixing dowel-crowns 
 are not, of course, put forward as novel, but only as 
 seeming to me superior to those already remarked upon, 
 and as most generally useful. The method of obtaining a 
 model to work to is, however, new, to the best of my know- 
 ledge. 
 
 To make a Collar-Crown. 
 
 The first thing to do in making a collar-crown by the 
 method now to be described is to obtain a mandrel for 
 shaping the collar (Fig. 98). This being done in the 
 manner already explained (pp. 45 — 49), the copper ferrule 
 in which the mandrel is cast is cut through on the lingual 
 side and peeled off, and the mandrel is trimmed into a 
 cylindrical shape to make it easy of removal from the 
 finished crown. The utmost care must be taken in doing 
 this, and throughout the work, not to damage the lower 
 margin of the mandrel, that viz. which comes into contact 
 with the model, and which represents the neck of the tooth 
 to be fitted. 
 
 A suitable crown (Fig. 97) is now struck up in the 
 way described on pp. 49 — 52, chased upon the natural tooth 
 with a steel punch carried in a 
 handle and used as a pressure- 
 punch (Fig. 56) and has its edge 
 made plane by filing and rub- 
 bing on a wet slate. 
 
 The mandrel being in posi- 
 
 ,, 6 l Fig. 97. Fig. 98. 
 
 tion on the model with some 
 
 composition, consisting of two parts of resin to one of wax, 
 
 on the top of it, the crown is heated and placed upon this 
 
8G 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 composition, and the proper occlusion is obtained by arti- 
 culating the models (Fig. 98 a). The advantage of being 
 able to do this in this way need hardly be insisted on. 
 
 Fig. 98 a. 
 
 The next step is to make up the mandrel with the 
 above -described composition between its lower margin and 
 the edge of the crown as fixed by the occlusion, 
 the composition being trimmed so as just to clear 
 the edge of the crown and to leave the lower 
 margin of the mandrel visible at all points 
 (Fig. 99). 
 
 A pattern of the surface of the composition 
 thus applied is now to be obtained and transferred 
 to the gold selected for the collar. This is done as follows : — 
 Place a strip of paper round the mandrel, making the ends 
 meet on the lingual side and, holding the mandrel and paper 
 in one hand, touch the points of the finger and thumb of the 
 other upon articulating paper, and rub them all round the 
 paper on the mandrel. On being now removed from the 
 mandrel, the paper will be found impressed with an outline 
 
 Fig. 99. 
 
 Fig. 100. 
 
 of the desired collar (Fig. 100). This being cut out, and at- 
 tached to the selected sheet of gold (Fig. 101) by means of 
 wax previously flowed over the gold, the collar is cut out 
 
CROWN AND BRIDGEWORK. 
 
 87 
 
 (Fig. 102), finally adjusted to the mandrel and soldered into a 
 ferrule. The crown edge of this is made plane by filing and 
 
 Fig. 101. 
 
 Fig. 102. 
 
 u 
 
 rubbing on a wet slate, as was before done with the crown, 
 and the other edge is filed to the form of the mandrel. The 
 crown and the ferrule are then an- 
 nealed and boiled in pickle, fitted 
 together, held in position with a 
 piece of bent binding- wire as shown 
 in Fig. 103, soldered together, and 
 the crown is complete. The crown 
 is then boiled in pickle, and finished 
 in the usual way. Figure 104 shows 
 the finished work. 
 
 Lastly, the patient returns and, 
 the crown having been tried on the 
 root and found to fit, a tapering screw post may, if thought 
 advisable, be inserted in the root (p. 32) ; the crown, filled 
 
 Fig. 103. 
 
 Fig. 104. 
 
 with phosphate cement, is pushed into position ; the super- 
 fluous cement is removed, and the work is done. 
 
 When filling the crown with cement, it is convenient 
 to hold it by means of a piece of tape waxed and wrapped 
 about it; the tape will prevent the cement from smearing 
 the outer surface of the crown. 
 
88 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 By a method similar to that described above a porcelain- 
 faced crown, or a cap and band to carry a tube-tooth, 
 
 may be made for a bicuspid. 
 
 The precision and accuracy with which each step in the 
 above process may be taken, and the entire absence of all 
 uncertainty and guesswork and of the necessity for repeated 
 reference to the natural root render this method of making 
 a collar-crown, which may perhaps seem complicated to 
 read about, at once simple, successful, and comforting beyond 
 any that I have hitherto tried. 
 
 On the other hand, the shape taken by the gold strip 
 (Fig. 102), which when soldered becomes the collar, shows 
 that the attempt to fit a root with a ready-made collar-crown 
 from the depots is likely to be almost as picturesque in result 
 as the attempt to fit Tom, Dick, or Harry with a ready-made 
 coat. But if there were neither lame dogs nor stiles there 
 would be no ready-made crowns, and it would be gratifying 
 to feel that one had done something, were it never so little, 
 to make both cripples and crutches things of the past. 
 
 The illustrations relating to the Collar-Crown above 
 described were taken from a case in practice, the original 
 models for which, together with the supplementary models 
 shown above and a duplicate crown, are now at the Dental 
 Hospital of London. 
 
 In conclusion, I can only hope that those of my readers 
 who may have persevered in following me so far will forgive 
 the possibly obtrusive egotism attending much that I have 
 said, as being perhaps inevitable under the circumstances. 
 
 If they should also agree that anything here put forward 
 is at any rate worthy of refutation, I shall feel that some- 
 thing has been gained in the promotion of a discussion which 
 will ultimately lead to the adoption of the best methods, and 
 to the lasting benefit of those whom it is at once our duty 
 and our pleasure to serve. 
 
APPENDIX. 
 
APPENDIX. 
 
 WORKING DESCRIPTIONS OF METHODS TREATED 
 OF IN THE FOREGOING PAGES. 
 
 For reference in Workroom or Surgery. 
 
 Making a Collar-Crown. 
 
 1. To make a mandrel for the collar. 
 
 Prepare the root by sawing off the crown, if any, to within 
 about a sixteenth of an inch of the gum by means of a saw 
 
 Fig. 1. 
 
 cutting at right angles to its frame (Fig. 1). Strip off the enamel 
 with trimmers (Ash's, Nos. 3 and I), to make the root cylindri- 
 cal, and build up with amalgam should the decay extend beyond the 
 
92 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 a 
 
 Fig. 2. 
 
 Fig. 3«, 
 
 Fig. 3 b. 
 
APPENDIX. 
 
 93 
 
 gum margin. Place a copper strip (Fig. 2) about a natural tooth, 
 somewhat smaller than the root to be treated, and draw it into 
 shape by grasping the ends with pliers (Figs. 3a or 3b). Anneal 
 and boil the resulting ferrule (Fig. 4) to make it soft and clean ; 
 place it about the root, and draw the ends together with the pliers, 
 as before, until its shorter edge takes accurately the form of the 
 root as far beyond the gum margin as the strip will go. Remove 
 the ferrule, still grasped by the pliers ; wash and dry, and solder 
 with soft solder. Trim the ends as in Fig. 4 ; replace the ferrule 
 
 Fig. 5. 
 
 Fig. 6. 
 
 Fig. 7. 
 
 Fig. 8. 
 
 as far on the root as before (Fig. 5) ; lightly fill with wax (Fig. 6), 
 leaving the edge of the ferrule clear; and take impressions of 
 both jaws with composition. Having removed the impressions, 
 replace the ferrule if disturbed ; fill with wax the part not yet 
 filled, which should then be visible (Fig. 7) ; and scrape down the 
 wax until the edge of the ferrule can just be seen all round 
 (Fig. 8). Warm the head of half an ordinary brass pin, and 
 thrust it head downwards into the wax towards the buccal side of 
 the ferrule (Fig. 8), taking care to keep the pin upright. Make 
 the plaster models with the ferrule and pin in position in the 
 impression. Draw the model, taking care not to disturb the 
 
94 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 ferrule from it (Fig. 9), and scald out the wax. Remove the pin ; 
 cut a small depression (Fig. 10) in the plaster within the 
 ferrule towards its lingual side by means of the excavator 
 (Fig. 11); replace the pin ; pour fusible metal into the 
 ferrule from the cup (Fig. 12) standing ready in boiling 
 water ; and press lightly with the finger upon the metal 
 
 Fig. 9. 
 
 Fig. 10. 
 
 Fig. 11. 
 
 Fig. 12. 
 
APPENDIX. 
 
 95 
 
 as it cools (Fig. 13). Remove the mandrel and ferrule from the 
 model, cut the ferrule through on the lingual side, and peel it off 
 the mandrel. A mandrel is thus obtained in fusible metal, with 
 
 Fig. 13. 
 
 a pin and a boss (A, Fig. 3, or Fig. 14) to fix its position on the 
 model. Trim the mandrel to make it cylindrical 
 and easy of removal from the finished crown, but be 
 careful not to touch its lower edge, unless the ferrule 
 was found to leave the root too easily, in which case 
 the lower edge may be slightly reduced by scraping. 
 Figure 15 shows a mandrel in position on the 
 plaster model, ready for use in shaping the gold collar to which 
 the crown (grinding surface) is to be soldered. 
 
 Fig. 14. 
 
 Fig. 15. 
 
 2. To make a die for striking up a gold crown. 
 
 Fill the split ring in the mould (A, Fig. 16) with composition, 
 and allow it to cool. Warm the exposed end of the composition 
 to the depth of about an eighth of an inch ; wet and plant a 
 natural tooth, crown downwards, in the centre of it (Fig. 16). 
 When the composition is again cool, remove the tooth, and polish 
 the surface of the composition with a file and glass paper, finish- 
 ing with the back of the paper. Slightly warm the tooth, and 
 
96 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 replace it in the composition. Warm the split ring (Fig. 17), 
 and place it, large end downwards, on the composition, so as to 
 be co-axial with the tooth. From the cup (Fig. 12) pour into 
 this ring enough fusible metal to cover the root, which may be 
 shortened if necessary. Slip up the wires on the split ring a little 
 and remove the die (Fig. 18). Make a mark on the lingual side 
 of the die with the excavator (Fig. 11). 
 
 A die of this kind may be made somewhat more readily by 
 
 Fm. 16. 
 
 Fig. 17. 
 
 Fig. 18. 
 
 Fig. 19. 
 
 the use of clay instead of composition, the surface of the clay 
 being made smooth bypassing a piece of glass over the end of the 
 split ring containing the clay. No warming and polishing are 
 then necessary, but the resulting die is less finished than that 
 obtained by the use of composition. 
 
 3. To strike up a crown. 
 
 Insert a die (Fig. 18) into the punch (Fig. 19). Wet a piece 
 of sheet gold (No. 6) ; place it on bees-wax, melted into and 
 filling the bottom of a vulcanite flask, and drive the gold into the 
 wax by a few blows of a hammer upon the punch, keeping the 
 mark on the die always in one direction, say towards the person ; 
 
APPENDIX. 
 
 97 
 
 anneal the gold about three times in the process. Fig. 20 shows 
 the result. 
 
 If the weather be warm, cool the wax be- 
 fore using it by letting water run on to it from 
 a tap. 
 
 Drop the die, face uppermost, into the hole 
 in the board (Fig. 21) to keep it steady, and 
 chase the crown (Fig. 20) upon the natural 20- 
 
 tooth with a steel punch (Fig. 22), carried in a handle and used 
 
 Fig. 21. 
 
 Pig. 22. 
 
98 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 as a pressure-punch ; trim the crown with shears, and make the 
 edge plane by filing and rubbing on a wet slate. 
 
 4. To obtain the occlusion. 
 
 Make up the mandrel with composition, consisting of two 
 parts of resin to one of wax, to a height calculated to give a suit- 
 able occlusion, and place it in position on the model. Heat the 
 
 Fig. 23. 
 
 crown ; place it on the top of the composition, and obtain the 
 proper occlusion by articulating the models (Fig. 23). 
 
 5. To make the collar and join it to the crown. 
 
 Make up the mandrel between its lower margin and the edge 
 
 of the crown, as fixed by the occlusion, with the above described 
 
 composition ; and trim the composition so as just to 
 
 clear the edge of the crown and leave the lower edge 
 
 of the mandrel visible at all points (Fig. 24), being 
 
 careful not to damage the edge of the mandrel while 
 
 doing so. Place a strip of paper, of the same shape 
 
 as the copper strip (Fig. 2) but wider, round the 
 
 mandrel, making the ends of the paper meet on the 
 
 Fig. 24. i m g Ua i s i c ] e . Holding the mandrel and paper in one 
 
 hand, touch the points of the forefinger and thumb of the other 
 
 Fig. 25. 
 
 hand on articulating paper, and rub them all round the paper on 
 the mandrel. Cut ofi' what is superfluous in the length of the 
 
APPENDIX. 
 
 99 
 
 paper, remove the paper from the mandrel, and cut out the 
 pattern outlined upon it by the rubbing (Fig. 25). Flow some 
 wax over one side of a piece of sheet gold (No. 6 or thinner), 
 
 Fig. 26. 
 
 Fig. 27. 
 
 attach the paper pattern to the waxed surface by heating (Fig. 26), 
 and cut out the gold to the pattern (Fig. 27). Wrap the strip of 
 gold about the mandrel, bringing the seam to the lingual side ; 
 make any little adjustment that may be required, and solder the 
 strip into a collar. Make the crown edge of the collar plane by 
 tiling and rubbing on a wet slate, and file the other edge to the 
 form of the mandrel. 
 
 on 
 
 Fig. 28. 
 
 Fig. 29. 
 
 Anneal and boil the crown and collar; fasten them together 
 with a piece of binding wire, bent as in Fig. 28 ; solder ; and the 
 crown is complete (Fig. 29). 
 
 Repairing Vulcanite Plates. 
 
 6. To repair a vulcanite plate from which a 
 single tooth has heen broken. 
 
 Cut a dovetail as if about to vulcanise a tooth in. Drill two 
 small depressions, one in either edge of the dovetail ; secure the 
 booth in position temporarily from the front with shellac; melt 
 some fusible metal into the dovetail with the handle of an 
 
 7—2 
 
100 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 excavator (Fig. 11) made hot, or by pouring from the cup (Fig. 
 12), and apply a slight pressure with the finger to the metal as it 
 cools. 
 
 It is best to use flat-teeth for incisors or canines. 
 
 7. To repair a cracked vulcanite plate. 
 
 Secure the parts of the plate in position with wax, and set it 
 in plaster of Paris. To the part where the strengthening plate is 
 to be attached, apply a disc of sheet wax rather larger than the 
 metal plate is to be ; cover this completely with composition, and 
 make a hole in the centre of the composition through which 
 
 CASH & SONS ■- = 
 
 Fig. 30. 
 
 fusible metal may be poured. Lift off the composition, remove 
 the wax, replace the composition, and pour in fusible metal from 
 the cup (Fig. 12). Set the cast thus ob- 
 tained, face downwards, in a layer of 
 clay on the plate A, Fig. 30. Wind 
 a strip of celluloid about the posts (Fig. 
 30), secure it with string so as to form 
 a ferrule round the posts, and pour fusi- 
 ble metal from the cup (Fig. 12) into it 
 to unite with and strengthen the cast 
 (see Fig. 31, A and B). Place the die 
 thus strengthened, face upwards, be- 
 tween the posts (Fig. 30) ; smear the 
 face with rouge and water, or whiting 
 and water, and with the help of the 
 celluloid ferrule cast the counter-die 
 (Fig. 31). To strike-up the metal plate, 
 
 Fig. 31. 
 
APPENDIX. 101 
 
 place the washer (Fig. 32) upon the plate A, Fig. 30, then the 
 die face upwards, then the plate to be struck-up, then the 
 counter-die, in the order named, and hammer away. 
 
 The purpose of the washer (Fig. 32) is to raise the counter-die 
 above the tops of the posts to permit of the striking-up process. 
 
 Making New Vulcanite Plates. 
 
 8. To make a base or trying-in plate. 
 
 Fit a wax-plate to the usual plaster model, and trim it to the 
 size of the desired trying-in plate. Make a rod of wax about 
 three times as thick as the wax-plate and half an inch wide, and 
 place it along the centre-line of the model from the back of the 
 wax-plate to the back of the model. Wet the wax and cover the 
 whole completely with composition, from a quarter to half an 
 inch thick. When this is set, remove it and take out the wax ; 
 replace the composition on the model, and see that the orifice 
 made by the wax rod extends not less than an inch further back 
 than any part of the wax-plate extended. Then, holding the 
 mouth of the orifice uppermost, pour in fusible metal from the 
 cup (Fig. 12) till the orifice is completely filled. When the cast 
 is set, remove the composition ; carefully work off the plate from 
 the model, and trim it up with the handle of an excavator (Fig. 
 11) made hot. Sometimes, in flashing, a plate thus obtained will 
 be found difficult of removal from the model when invested. In 
 such a case, divide the plate into two or more parts by means of 
 the excavator handle made hot, and remove the parts separately. 
 If the plate happens to have been at all rough, smooth the model 
 cast by means of it (p. 12) by rubbing with the finger wrapped 
 in a soft rag. 
 
 9. To make an articulator. 
 
 Trim the models so that, when articulated, their backs will sit 
 comfortably in the square tray (Fig. 33). Fix the small oval tray 
 (Fig. 34) by means of the split tube and disc (Fig. 35) in the 
 centre of the tray (Fig. 33) ; trim the models, and adjust the tray 
 (Fig. 31) so that it will pass between the models when the latter 
 are held in the position given by the bite and seated comfortably 
 on their backs in the larger tray. If using the trays for the first 
 time, paint all the interior with rouge and water. Place the 
 
102 
 
 OPERATIVE ANT) MECHANICAL DENTISTRY. 
 
 square tray (Fig. 33) in a shallow pan of water ; put in as much 
 fusible metal as will, when melted, from a half to three parts fill 
 the tray, and make the water boil. When the metal is melted, 
 remove the tray from the pan ; pour away the hot water ; replace 
 the tray in the empty pan ; invest the models in correct occlusion 
 in the molten metal, and pour cold water into the pan to hasten 
 the cooling. Remove the models and the split tube and disc 
 
 Fig. 33. 
 
 Fig. 35. 
 
 (Fig. 35) ; turn out the slab from the tray (Fig. 33), and push 
 out the small oval tray (Fig. 34) from the centre of the slab. 
 
 Of course, the backs of the models must be so trimmed, or 
 made up with clay, before being invested, as to be capable of 
 removal from the metal slab (see Figs. 36 and 37). 
 
 Matrices. 
 
 10. To apply, retain, and remove matrices. 
 
 Take a matrix (Fig. 38) of the size required, and with a suit- 
 able pair of pliers bend each end to a right angle along one of the 
 lines marked upon it. Slip the ' lugs ' so formed into the slots of 
 the clamp (Fig. 39), which should be previously opened wide for 
 the puupose, taking care to insert the lugs in such a way that, 
 
APPENDIX. 
 
 103 
 
 Fro. 36. 
 
 Fig. 37. 
 
104 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 when the matrix is on the tooth the head of the clamp-screw 
 shall be towards the front of the mouth. Pass the matrix on to 
 the ungrooved end of the shaping-tool (Fig. 40), and tap it into 
 symmetrical shape (Fig. 41) ; then slip it on to the other end and 
 press grooves into the lower margin at such points as will accom- 
 modate the grooves in the tooth to be treated. The upper margin 
 of the matrix may sometimes be contoured with advantage. 
 
 To apply the matrix thus prepared to the tooth, slip the 
 small end first on to the tooth and tighten the clamp with the 
 key (Fig. 42). 
 
 If it is desired to retain the matrix upon the tooth for a few 
 hours after filling, attach a loop of wire to the twister (Fig. 43) 
 by threading the ends of the wire through the holes in the instru- 
 ment and twisting them round the handle. Slip this wire loop 
 over the clamp and behind the lugs of the matrix, and, holding 
 the instrument so as to close the loop lengthwise of the tooth, 
 first give it a few turns so as to twist the ends of the wire 
 together ; then remove the clamp, and give the twister a few 
 more turns to tighten the wire. Cut off the superfluous wire, 
 bend the cut ends behind one of the lugs of the matrix, and press 
 thi' lugs against the tooth. 
 
 To remove the matrix, draw the lugs together, and slip off the 
 loop. 
 
 To shorten a matrix, bend it at an inner line, after clipping 
 the end to the same shape as for an outer line. 
 
 To reach a very deep cervical cavity, clip away either or both 
 lugs along the lower margin, that is, along the shorter curve 
 of the matrix. The strip cut off should narrow away to nothing 
 before the middle of the matrix is reached, and the effect will be 
 to somewhat straighten the shorter curve of the matrix, but this 
 will have the desired effect, and more cannot be done without 
 disadvantage. 
 
 Dowel-Crowns. 
 
 11. To obtain a cast of a root-face with the 
 direction and depth of the root-canal for the purpose 
 of making a dowel-crown. 
 
 Trim the root-face to a convex form ; seal the apex ; prepare 
 
APPENDIX. 
 
 105 
 
 Fig. 40. 
 
 Fig. 42. 
 
 Fig. 39. 
 
 - : 
 
 Fig. 38. 
 
 Fig. 41. 
 
 I 
 
 Fig. 43. 
 
106 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 the canal, and take the depth of the canal with one of the root- 
 sounds or measuring-posts (Fig. 44). 
 
 Fill with composition a conical cap of suitable size (Fig. 45), 
 which can he made narrower by pressure, if necessary, so as to 
 
 u 
 
 I 
 
 : 
 
 v w 
 
 Fig. 41. 
 
 Fig. 45. 
 
 Fir. 46. 
 
 Fig. 47. 
 
 pass readily between the teeth adjacent to the root ; pass one of 
 the root-canal posts (Fig. 46) through the middle of the composi- 
 tion and through the orifice at the apex of the cap, a broach being 
 first used to open up a way for the post ; soften the surface of 
 the composition and shape it into a mound about the post 
 
 Fig. 48. 
 
 (Fig. 47). Apply the cap thus tilled to the root-face, while the 
 composition is still soft, first passing the post into the canal, then 
 pressing the cap home and cooling it by means of a syringeful of 
 cold water. 
 
APPENDIX. 
 
 107 
 
 Remove the cap and post from the root ; cut away the 
 superfluous composition from the outside of the cap ; reapply the 
 post and cap to the root, and take the general impression with 
 one of the trays shown in Figs. 48 and 49. In doing this make 
 
 Fig. 49. 
 
 the post strike the centre of the composition in a direction 
 towards the front of the tray which will then guide the post 
 unerringly through the slot. Cool the impression by means of 
 the syringe as before ; remove the post, and then the impression. 
 
108 
 
 OPERATIVE AND MECHANICAL DENTISTRY. 
 
 Replace the post in the impression, and fix it with wax applied to 
 the tray ; place a short roughened copper tube on the end of the 
 post which is to enter the plaster model (Fig. 50) ; cast the 
 model ; withdraw the post, and the copper tube will remain 
 
 Fig. 51. 
 
 Fig. 52. 
 
 behind in the model, forming an indestructible reproduction of 
 the root-canal (Fig. 51). 
 
 Two or more roots may be treated simultaneously in the same 
 impression, whether it be a partial or a full one (Fig. 52). 
 
INDEX. 
 
 A brief description of a dowel-crown demonstration 
 Adding a tooth to a vulcanite case without casting a model 
 Advantage of sending early for a dentist in cases of fractured 
 jaw or of epithelioma ....... 
 
 Another point in connexion with trays (Clearing of com- 
 position) 
 
 Anterior teeth, disfigurement due to want of, avoided . 
 
 „ „ crowning, to obtain a model with a view to 
 
 Arch, width of, in setting up teeth 
 
 Articulators 
 
 „ useless complication of many 
 
 „ essentials of 
 
 „ „ „ how attained 
 
 „ how to make of Fusible Metal 
 
 „ removal of Fusible Metal slab, from the casting 
 
 trays 
 
 Asbestos, use of, in soldering 
 Ash's Mineral Teeth, notes on 
 to grind 
 ,, „ „ to polish 
 
 ,, ,, ,, equipment for grinding and polishing 
 
 PAGE 
 81 
 15 
 
 61 
 
 28 
 
 82 
 
 77—80 
 
 8 
 57, 101 
 
 59 
 
 21, 22, 23 
 
 18—20 
 
 19 
 
 19 
 
 19, 20 
 
 Backing and soldering teeth .... 
 
 Band, soldering a pin-tooth on a plate near a 
 Base-plate (see also under Making a Base, &c.) 
 „ use of Fusible Metal in making a 
 
 Base, cracked vulcanite, repair of . 
 Base of vulcanite, tube-teeth on a 
 Bent metal plate, model for correcting a 
 Bent scrapers, how to make .... 
 
 Bent wire, use of, in soldering a crown to a collai 
 Bicuspid crown, gold, with mineral face 
 Bites, shallow ...... 
 
 Bite, taking a (see also under Taking a bite) 
 
 22 
 24 
 
 7 
 55 
 25, 54, 100 
 17 
 60 
 28 
 52 
 23, 88 
 18 
 
 7 
 
110 
 
 INDEX. 
 
 Board to steady the die while chasing a crown 
 Boiling out in packing avoided .... 
 
 Bolt-heads for swivel-bolts, how to make 
 „ „ how to affix 
 
 ,, „ how to finish 
 
 Bolts for springs, position of .... 
 
 „ „ how inserted .... 
 
 Bon will Grown, faults of ..... 
 
 Brass pins, ordinary, use of, in making solder 
 
 ,, „ „ „ a collar-crown 
 
 Bridge- work ........ 
 
 „ a priori objections to . 
 
 ,, statistics relating to . 
 
 „ Drs Melotte and Barrett on 
 
 Broaches, use of, as drills 
 
 Broach-holder {see also under Wire or Broach-holder) 
 Brunton Polishing Wheels and Points . 
 
 „ Two-Part Contour Flask 
 Biittner Method of crowning, faults of . 
 
 PAGE. 
 
 52 
 16 
 36 
 36 
 37 
 9 
 !) 
 75 
 24 
 46 
 2—74 
 72 
 73 
 72 
 21 
 35 
 2o 
 15 
 76 
 
 Canals, Root- {see under Etoot-Canals). 
 
 Cap and baud to carry a tube-tooth, to make a . 
 
 Caps, conical (see under Conical Caps). 
 
 I lasting a model ......... 
 
 „ „ use of wires to strengthen teeth in, de- 
 
 precated ...... 
 
 }J „ when some of the teeth lean over 
 
 „ „ adding a tooth to a vulcanite plate without 
 
 Cavity, cases in which the gum has crept into a, treatment 
 
 of 
 
 „ deep cervical, how to apply a matrix to 
 „ „ „ preparation of, facilitated 
 
 Cervical Cavity (see under ( lavity). 
 Cervical Clamp, modified .... 
 
 Clamp, matrix- ...... 
 
 „ how to insert matrices in a . 
 
 ,, how to put together the parts of 
 
 ( 'lamp, modified cervical .... 
 
 Clamps, spring-, substitute for 
 Clay, use of, in making a counter-die . 
 „ „ ,, a natural tooth die . 
 
 „ „ „ an articulator . 
 
 „ „ in casting a fusible metal die for repairing 
 
 vulcanite plates ..... 
 
 4 
 
 4 
 
 15 
 
 68 
 
 68, 70, 104 
 
 70 
 
 33 
 65 
 65 
 69 
 33 
 52 
 5 
 50 
 100 
 
INDEX. 
 
 Ill 
 
 Collar-Crown, method of making a mandrel for a 
 „ to make a 
 
 „ to obtain the proper occlusion of a 
 
 to make up with composition a mandrel for a 
 „ t<> obtain a pattern for the Collar of a 
 
 „ to cut out a Collar for a . 
 
 „ to solder together Crown and Collar for a 
 
 „ to insert a ..... . 
 
 „ ready-made, use of, deprecated 
 
 Composition, method of taking an impression with 
 „ to hasten the setting of . 
 
 „ and Plaster, uses of, in taking an impression 
 
 compared ........ 
 
 Cone-socket Points, pliers for inserting and removing . 
 
 Conical Caps for taking impressions of root-faces 
 
 ( 'oiitracting the arch in setting up teeth, reasons fo] 
 
 disputed 
 
 ( on trivance for saving impression-trays 
 ( lopper Strip, shape of, for making a ferrule 
 ( 'opper-Tube, light, use of, in soldering, &c. . 
 Counter-Die, shallow, disadvantage of a 
 „ deep, how to obtain a 
 
 „ use of clay in making a . 
 
 Counters, number of, required in making a gold-plate . 
 Countersinking vulcanite, when riveting, unnecessary . 
 Cracked vulcanite plate, repair of a 
 Crown and Bridgework . 
 Crown, gold bicuspid, with mineral face 
 Crown, Bonwill, faults of 
 
 „ Buttner, „ ... 
 
 „ Logan, „ ... 
 
 „ Richmond „ ... 
 
 Crowning, certain methods of. discarded 
 
 „ method of, very feeble anterior roots . 
 
 ,, very poor bicuspid roots, method of 
 
 „ methods and systems of, discussed 
 
 „ one or more anterior teeth, method of obtainin 
 
 a model with a view to .... 
 „ preparing a septic tooth for . 
 Crown of tooth, living or dead, method of removing 
 
 „ „ „ „ „ objections 
 
 to, considered .... 
 
 Crown, revived form of all-porcelain, for use as a dowel- 
 crown .......... 
 
 PAGE 
 
 -48, 91 
 -87, 91 
 
 85, 98 
 86,98 
 
 86, 98 
 86,99 
 
 87, 99 
 
 2 
 
 ■2 
 
 1 
 33 
 
 78 
 
 9 
 
 27 
 
 45, 48 
 
 23, 84 
 
 4 
 
 5 
 
 26 
 
 54, 100 
 
 72—88 
 
 23, 88 
 
 75 
 
 76 
 
 75 
 
 76 
 
 76 
 
 76 
 
 76 
 
 76 
 
 7 I 
 
 -80 
 81 
 81 
 
 81 
 
 82 
 
112 
 
 INDEX. 
 
 Crown, soldering a, to a collar 
 
 „ to apply a dowel- 
 
 „ to make a collar- 
 
 „ gold, to strike up a, for a collar 
 Cutters for shortening mineral teeth 
 
 „ gold-, to save waste when using 
 Cutting up vulcanite work, tools for 
 
 Demonstration, dowel- crown, brief description of 
 Dentist in case of fractured jaw or of epithelioma 
 Descriptions, Working, of Methods {see under Working 
 
 Descriptions, &c). 
 Die, advantages of a Pearsall flask in making a . 
 „ how to make a, for striking up a gold plate . 
 ,, „ „ for the repair of a vulcanite plate 
 
 Dies, number of, required for striking up a gold plate . 
 „ natural-tooth, use of, in treating shallow bites 
 „ „ for striking up crowns . 
 
 Dipping and making up a model ..... 
 Disfigurement due to want of anterior tooth avoided . 
 Dowel-Crown appliances, to take an impression with . 
 „ preparation of a plate- tooth for use as a 
 
 „ „ ,, tube-tooth „ „ 
 
 „ revived form of all-porcelain crown for use as a 
 
 to apply a .... 
 „ method of fixing a . 
 
 „ fractured, removal of, ensured 
 
 Drills, broaches used as ... 
 
 Edentulous case, very aged, how met . 
 
 Emergency arising from the loss of a single tooth, to meet an 
 
 „ partial plate of fusible metal to be worn in an 
 
 Enlargement of root-canals avoided 
 Epithelioma, dentist should be called in before an operation 
 
 for 
 
 Excavator brought to a needle point, uses of 
 
 „ spade-shaped, uses of . 
 
 Feathered Post, use of, in crowning deprecated 
 Ferrule, how to adapt a, to a given tooth 
 
 „ „ make of given dimensions 
 
 Files, three-sided, use of 
 
 „ knife-edged, „ ... 
 
 oval root- „ ... 
 
 PAGE 
 
 52, 87, 98 
 
 82—84 
 
 85—87, 91 
 
 - 50, 95 
 
 20 
 
 30 
 
 28—30 
 
 80 
 61 
 
 5 
 
 5 
 54 
 
 5 
 
 18 
 
 49, 95 
 
 4 
 82 
 -80, 104 
 82 
 83 
 82 
 82—84 
 83 
 84 
 21 
 
 10 
 53 
 
 56 
 
 84 
 
 61 
 21, 29 
 
 46, 50 
 
 75 
 48 
 48 
 29 
 29 
 29 
 
INDEX. 
 
 113 
 
 Filling up the interstices in a gold-bar lower 
 Fitting a gold-plate with side-pieces for swivels . 
 Flask, Pearsall sand-moulding, advantages of 
 
 „ Brunton Two- Part Contour 
 
 „ vulcanite (see under Vulcanite Flask). 
 Flasking 
 
 ,, saving the original model when 
 
 „ making a second model for . 
 
 „ an edentulous case, method of 
 
 „ a partial case, „ „ . . 
 
 ,, and packing, to prevent disturbance of bands and 
 
 wires when ..... 
 
 „ to prevent contraction of plate in . 
 
 Formalin, applied to a septic tooth 
 Fractured jaw, dentist should be sent for early in cases of 
 Frenum, &c, to clear plate from the 
 
 Friction on springs avoided 
 
 Fusible Metal, constituents and expansion of 
 
 „ „ some uses of . 
 
 „ „ use of, to make a mandrel for a collar-crown 
 
 „ ,, „ „ die for striking up crowns 
 
 „ „ „ „ a model in pivoting . 
 
 „ „ „ in fixing a tooth to a vulcanite plate 
 
 ,, „ ,, in the repair of cracked vulcanite 
 
 plates .... 
 
 „ „ „ to make a base-plate . 
 
 „ „ „ „ partial plate for wear in an 
 
 emergency 
 
 „ „ „ to make a slab articulator . 
 
 „ „ „ to fill up interstices in a gold-bar 
 
 lower .... 
 
 „ „ „ to make a model for correcting a bent 
 
 metal plate .... 
 
 „ „ „ to make a model to give the articula 
 
 tion when many natural teeth remain in one jaw . 
 Fusible Metal, use of, to make a splint 
 
 Gateways for the escape of excess of rubber in packing 
 
 dispensed with .... 
 Gold-base, hint as to vulcanising on a . 
 Gold bicuspid crown with mineral face 
 Gold-Cutters, to save waste when using 
 Gold- Plate, fitting a, with side-pieces for swivels . 
 
 „ making a (see also under Making a Gold-Plate) 
 
 L. 
 
114 
 
 INDEX. 
 
 Gold- Plate, to cement tube- teeth to a . 
 
 Gold Solder 
 
 Gouges, handles for ...... 
 
 Grooves, to adapt a matrix to the, in the sides of teeth 
 Gum, treatment of, when it has crept into a cavity 
 
 Handles for scollopers and gouges 
 
 Hot-water syringe, new 
 
 ,, „ disadvantages of the common form of 
 
 „ ,, to fill and empty new form of. 
 
 Hydrochloric acid, use of, after vulcanising . 
 
 Impression, obtained with dowel-crown appliances . . 80 
 
 „ of a root-face, to take an . . . . 77 — 79, 104 
 
 „ taking an (see under Taking an impression). 
 
 ,, trays, special 
 
 „ „ contrivance for saving 
 
 Interstices, to fill up the, in a gold-bar lower 
 
 Jaw, fractured, dentist should be sent for early in case of 
 Jeweller's wig, use of, in soldering .... 
 
 Knitting-needle, use of pieces of, when inserting bolts 
 
 PAGE 
 
 24 
 24 
 30 
 06 
 68 
 
 30 
 33 
 33 
 33 
 17 
 
 Lathe, method of wetting wheels on a . 
 
 „ to centre wheels upon a .... 
 Logan Crown, faults of the ...... 
 
 Making a Base or Trying-in Plate .... 
 „ „ what is to be sought in 
 
 „ „ „ materials used in 
 
 H „ „ method of 
 
 Making a gold-plate 
 
 „ ,, disadvantages of a shallow counter in 
 
 „ „ to obtain a deep counter for . 
 
 „ use of clay to obtain a counter for 
 
 „ „ advantages of a Pearsall sand-moulding 
 
 flask in 
 
 „ number of dies and counters required i 
 
 „ „ method of swaging in . 
 
 n „ weight of hammer for swaging in . 
 
 „ „ disadvantages of swaging on a block i 
 
 „ „ pattern for use in . 
 
 suction-chambers avoided in 
 
 3, 79 
 
 27 
 60 
 
 61 
 
 22 
 
 25 
 25 
 
 75 
 
 7 
 7 
 7 
 55, 101 
 4 
 4 
 5 
 5 
 
 5 
 5 
 5 
 6 
 6 
 6 
 6 
 
IXDEX. 
 
 115 
 
 PAGE 
 
 Making up and dipping a model 4 
 
 Mallet, Pneumatic 38 — 43 
 
 Mandrel, to make a, for making a collar-crown . . . 45 — 48, 91 
 
 Matrices, how to make them and how to apply them . 62 — 71, 102 
 
 „ mistaken shape of most advertised forms of . . 62 
 
 „ correct form of, ascertained 64 
 
 „ method of making, to meet special cases . . 64 
 
 „ correct, form of ends of ..... . 65 
 
 „ clamp for applying ...... 65 
 
 „ to insert, in the clamp ...... 65, 102 
 
 „ uselessness of wedges in applying .... 66 
 
 „ to adapt, to grooves in the sides of teeth . . 66, 104 
 „ trimmed to cover deep cervical cavities . 68, 70, 104 
 
 ,, to secure, in position for any desired time . . 68, 104 
 „ to remove ........ 68, 104 
 
 Matrix, use of, in cases where gum has crept into a cavity . 68 
 
 „ to insert a, between closely-adjacent teeth 
 Matrix-clamp, double screw of a . 
 
 ,, to put together the parts of a 
 
 Matrix, hints as to the uses of a . 
 Method of making a screw-post 
 
 „ wetting wheels on a lathe . 
 Methods, working descriptions of (see under Working De- 
 scriptions, &c). 
 Mineral Face, gold bicuspid with ...... 
 
 Mineral Teeth (see under Ash's Mineral Teeth). 
 Model, adding a tooth to a vulcanite case without casting a 
 „ casting a (see under Casting a Model). 
 „ dipping and making up a . 
 
 „ to obtain a, giving root-faces and the directions of 
 root-canals ....... 77 
 
 „ to remove the, from the sand when about to cast a zinc 
 „ use of fusible metal to make a, in pivoting 
 „ for correcting a metal plate accidentally bent . 
 Models showing reproduction of root-faces and canals . 
 Mouth, working at the, avoided 
 
 70 
 
 69 
 
 69 
 
 70 ' 
 
 32 
 
 25 
 
 23, 88 
 
 15 
 
 79, 104 
 26 
 52 
 60 
 
 80 
 12, 76 
 
 Occlusion, to obtain the, for a collar-crown . 
 Packing 
 
 „ use of rag in, dispensed with .... 
 „ no boiling out in . . ... 
 
 ,, no gateways for escape of rubber in 
 1'artial cases, figure showing devices in the treatment of 
 
 85,98 
 
 16 
 16 
 16 
 16 
 14 
 
116 
 
 INDEX. 
 
 Partial Plate of fusible metal to be worn in an emergency 
 
 Pattern for a gold plate 
 
 „ to obtain a, for the collar of a collar-crown 
 Pearsall sand-moulding flask, advantages of . 
 Pins for tube-teeth, to mark the positions of 
 
 „ soldering, to plates 
 
 Pin-tooth, soldering a, on a plate near a band 
 
 Plaster and Composition, uses of, in taking impressions 
 
 compared 
 
 Plaster, Knife for trimming, when investing 
 Plate, Base or Trying-in (see under Making a Base 
 Trying-in Plate). 
 
 „ bent metal, model for correcting a 
 
 „ near a band, soldering a pin-tooth on a 
 
 „ vulcanite, repair of a 25 
 
 „ to keep a, clear of frenum, &c. . 
 
 „ soldering pins to a 
 
 „ base or trying-in, use of fusible metal in making a 
 
 „ partial, of fusible metal for wear in an emergency 
 Plate-tooth, preparation of a, for use as a dowel- crown 
 Pliers for inserting and removing cone-socket points . 
 
 „ screw-cutting 
 
 „ with curved chops, use of 
 
 „ „ straight „ „ 
 
 Pneumatic Mallet 
 
 „ ,, origin of 
 
 „ „ mode of working of. 
 
 „ „ rate and force of working of . 
 
 „ „ to avoid necessity of changing pluggers in 
 
 „ „ details of mechanism of . 
 
 Pocket-knife, uses of ....... 
 
 Points, cone-socket, pliers for inserting and removing . 
 Points and wheels, Brunton Polishing .... 
 
 Polishing wheels and points, Brunton's 
 
 Porcelain Crown, revived form of, for use as a dowel-crown 
 
 Porcelain-faced Crown, to make a 
 
 Positions of the pins for tube-teeth, to mark the . 
 
 Post, screw-, to make a 
 
 Post or dowel, to solder a, in a tube-tooth . 
 Post, feathered, use of a, in crowning deprecated . 
 Preparing a septic tooth for crowning .... 
 Pressure-Punch 
 
 PAGE 
 
 56 
 
 6 
 
 86, 98 
 
 5 
 
 21 
 
 21 
 
 24 
 
 1 
 
 29 
 
 60 
 24 
 53, 54, 99 
 2 
 21 
 55 
 56 
 82 
 33 
 32 
 45 
 45 
 38—43 
 38 
 40 
 41 
 41 
 42 
 29 
 33 
 25 
 25 
 82 
 88 
 21 
 32 
 23 
 75 
 81 
 51 
 
 Rag, use of, in packing dispensed with . 
 
 16 
 
INDEX. 
 
 117 
 
 PAGE 
 81 
 
 Removing the crown of a tooth, method of . 
 
 objections to, 
 answered ........ 
 
 Removing the slab from the trays in making a slab articu 
 lator ......... 
 
 Repairing a vulcanite plate 
 
 n „ „ making a die and counter for 
 
 Richmond Crown, faults of the 
 
 Riveting to vulcanite, countersinking unnecessary when 
 Root- Canals, enlargement of, avoided .... 
 
 „ to obtain a model giving metal-lined repro- 
 ductions of 77—79,104 
 
 „ root-sounds for taking the depth of . . . 78,106 
 
 Root-faces, to take impressions of .... 
 Root-sounds, for taking the depth of root-canals . 
 
 81 
 
 59 
 25, 53, 54 
 54 
 76 
 26 
 84 
 
 77—79, 104 
 78, 106 
 
 Sand-moulding flask, Pearsall, advantages of 
 Saw cutting at right angles to plane of frame 
 
 „ „ „ „ „ how to convert 
 
 a piercing saw into a 
 Scollopers and Gouges, handles fo 
 
 „ chamfered . 
 Scrapers, bent, how to make 
 Screw-cutting Pliers 
 Screw, double-, of a matrix- clamp 
 Screw or tapped-wire post, to make a 
 „ ,, „ to insert a 
 
 „ „ „ to avoid obstruction arising 
 
 from a 
 
 Screw, tapering, use of, in repair of vulcanite plates 
 
 Septic Tooth, preparation of a, for crowning 
 
 Setting up Teeth ........ 
 
 ,, ,, reasons for contracting arch in, disputed 
 
 Shallow Bites 
 
 „ „ Method of making shallow crowns for use in 
 
 Side-pieces for swivels on a gold plate .... 
 
 Silver solder 
 
 Single Tooth, addition of a, to a vulcanite plate . 
 Slab Articulator, to make a, of fusible metal 
 
 „ „ removing a, from the casting trays . 
 
 Socket-handles, to carry broaches for use as drills 
 Soldering a crown to a collar ..... 
 
 „ a pin-tooth to a plate in the neighbourhood of a 
 band ......... 
 
 5 
 31 
 
 31 
 30 
 30 
 28 
 32 
 69 
 32 
 36 
 
 36 
 
 26 
 81 
 
 18 
 18 
 22 
 24 
 53, 54, 99 
 57 
 59 
 21 
 52 
 
 24 
 
118 
 
 INDEX. 
 
 Soldering teeth .... 
 „ pins to plates 
 „ use of asbestos in . 
 Solder, silver and gold, how to make 
 Spade-shaped excavator, uses of . 
 Splint of fusible metal . 
 
 „ how secured in position 
 Split-pin and Tube, use of, in crowning deprecated 
 Sponge, use of, for wetting wheels on a lathe 
 Spring-clamps, substitute for, in soldering a collar-crown 
 Springs 
 
 „ where necessary 
 
 „ position of bolts for 
 
 „ how to insert bolts for . 
 
 „ use of ledges for 
 
 ,, to avoid friction on . 
 
 ,, contrivance in addition to, to meet 
 tulous case ..... 
 Statistics relating to Bridge-work 
 Stearine, models to be dipped in . 
 Suction-chambers, use of, abandoned . 
 Sulphur, use of, as a cement for tube-teeth 
 Surgeons in general should send earlier for a 
 
 certain cases .... 
 Swaging a gold-plate, method of . 
 
 ,, weight of hammer for . 
 
 „ on a block, disadvantage of . 
 Swivel-bolts, tools for making, how to make 
 Swivels, side-pieces for, on a gold-plate 
 Swivel, tool for making a flat surface for a 
 Syringe, hot- water (see also under Hot- Water Syringe) 
 
 „ 8 oz., use of, for cooling an impression in com 
 position 
 
 very 
 
 and 
 
 aged eden 
 
 dentist in 
 
 Taking a bite 
 
 „ „ disadvantages of a dummy-bite in 
 
 „ „ use of teeth in 
 
 Taking an impression, method of 
 
 „ „ Plaster and Composition for, com 
 pared 
 
 „ „ to hasten the setting of composition 
 
 in ..... 
 
 ,, „ use of special trays in 
 
 Tapering Screws, use of, in repairing vulcanite plates . 
 
 PAGE 
 
 22 
 
 21 
 
 21 
 
 24 
 
 46, 50 
 
 60 
 
 60 
 
 75 
 
 25 
 
 52 
 
 9 
 
 9 
 
 9 
 
 9 
 
 10 
 
 10 
 
 10 
 73 
 
 4 
 
 6 
 
 24 
 
 61 
 
 5 
 
 6 
 
 6 
 
 36 
 
 22 
 
 37 
 
 33 
 
 2 
 
 3 
 
 26 
 
INDEX. 
 
 119 
 
 Teeth, Ash's Mineral (see also under Ash's Mineral Teeth) 
 „ backing and soldering ..... 
 „ to adapt matrices to grooves in the sides of 
 „ closely adjacent, to insert a matrix between 
 „ setting up (see under Setting up Teeth). 
 „ which lean over on a model, treatment of. 
 „ on a model not to be strengthened with wire . 
 To cement tube-teeth on a gold-plate .... 
 centre wheels upon a lathe ..... 
 
 insert a tapped-wire post 
 
 make a fusible metal slab articulator 
 
 ,, silver and gold solder ..... 
 
 mark the positions of pins for tube-teeth 
 Tool for making a flat surface to receive a swivel or washer 
 for a swivel ........ 
 
 Tools for cutting up vulcanite work .... 
 
 „ for use in affixing heads to swivel-bolts 
 Tooth, single, addition of, to a vulcanite plate 
 
 „ anterior, disfigurement due to want of, avoided 
 „ living or dead, removing crown of 
 „ septic, preparation of, for crowning . 
 To remove the model from the sand when about to cast 
 a zinc ......... 
 
 save the waste attending the use of gold-cutters 
 shorten a tube-tooth ...... 
 
 solder a post in a tube-tooth ..... 
 
 strike up a crown for a collar-crown 
 strike up a gold plate for the repair of a vulcanite plate 
 Trays, impression-, contrivance for saving . 
 
 „ how to clear, from model ..... 
 
 „ special ........ 
 
 ,, irrigated, objections to 
 
 „ casting, removing a fusible metal slab from 
 Trimming Plaster, Knife for, when investing 
 Trough, use of a, for wetting wheels on a lathe . 
 Trying-in plate (see also under Making a Base or Trying 
 in Plate) ........ 
 
 Trying-in plate, use of fusible metal in making a 
 Tube and Split-Pin, use of, in crowning deprecated 
 Tube-teeth, on a vulcanite base ..... 
 
 „ „ „ „ advantages attending use of 
 
 „ to cement, to a gold-plate .... 
 
 „ to mark the positions of the pins for . 
 
 Tube-tooth, to make a cap and band to carry a . 
 
 PAGE 
 
 18—20 
 22 
 66 
 70 
 
 4 
 4 
 24 
 25 
 36 
 57, 101 
 24 
 21 
 
 37 
 
 28—30 
 
 36 
 
 53, 54, 99 
 
 82 
 81 
 81 
 
 26 
 30 
 20 
 23 
 50 
 55 
 27 
 28 
 3, 79 
 3 
 59 
 29 
 25 
 
 7 
 55 
 75 
 17 
 18 
 24 
 21 
 
120 
 
 INDEX. 
 
 PAGE 
 
 Tube- tooth, to shorten a 20 
 
 „ to solder a post in a 23 
 
 Vulcaniser, washer for 17 
 
 Vulcanising, disadvantage of delay after .... 16 
 
 „ on a gold base, hint as to .... 17 
 
 „ position of flask in ...... 17 
 
 Vulcanite base, repair of 25, 53, 54, 99 
 
 „ „ tube-teeth on a . . . . . . 17 
 
 ., „ adding a tooth to a, without casting a model 15 
 
 Vulcanite Flask, disadvantages of the common form of . 34 
 „ „ modifications of the common form of, 
 
 adopted 34 
 
 ,, work, tools for cutting up . . . . . 28 — 30 
 
 Washer for a swivel, tool for making a flat surface for . . 37 
 
 „ „ vulcaniser ........ 17 
 
 Waxing up a case, tools for 29 
 
 Wax, pink, use of, in making up models .... 4 
 
 Wedges, uselessness of, in applying matrices ... 66 
 
 „ how to obviate the use of, „ „ ... 66 
 
 Wetting wheels on a lathe, method of 25 
 
 Wheels and Points, Brunton Polishing .... 25 
 
 „ on a lathe, method of wetting 25 
 
 „ „ „ to centre 25 
 
 Wire or broach-holder, use of, in inserting screw posts . 35 
 
 ,, „ spanner for a 35 
 
 „ use of, to strengthen teeth on a model .... 4 
 
 „ ,, in a tooth which leans over on a model . . 4 
 
 „ bent, use of, when soldering a crown to a collar . . 52 
 Working Descriptions of Methods : 
 
 Making a Collar-Crown 91 — 99 
 
 Repairing Vulcanite Plates 99—101 
 
 To make a base or trying-in plate .... 101 
 
 „ „ an articulator 101 
 
 „ apply, retain, and remove matrices .... 102 
 
 „ obtain a model for making a dowel-crown . 104 
 
 Zinc die with cone obtained by use of Pearsall Flask . . 5 
 „ to remove the model from the sand when about to 
 
 cast a 26 
 
 CAMBRIDGE : PRINTED BY J. AND C. F. CLAY, AT THE UNIVERSITY PRESS. 
 
COLUMBIA UNlVERSrrv 
 
 ™» b00k „ due on ' d RSITY LI ^ARI ES 
 
 -Piration «**£?£** ^^ed below, or at the 
 Proved by the libr^^J?* **?** « ^owin^ 
 the Librarian i„ ctai ^ ° r by s * e ™ arra ngement *J 
 

 551 
 
 
 
 
 L54 
 
 
 Lennox 
 
 
 
 
 
 
 r " n -" r> " 
 
 a + Vin,- 
 
 Jg 
 
 Dn/l 
 
 onnl "i onr»r»c i r J 
 
 COLUMBIA UNIVERSITY LIBRARIES (hsl.stx) 
 
 RK 651 L54 C.1 
 
 Some methc 
 
 erative 
 
 2002377381 
 
■ 
 
 Hi iH