WIM£LL£- SjK REATISE ON THE USE OF ^ A. J. WATTS' I CRYSTAL GOLD. BY W. i i INELLE, M. D.,J>. D. S.,'4 v *... *■■ 1 1 U T 10 A : ROBERTS, PRINTER, 58 & 60 GENESEE ST. 1855. a*; T I l r^ ^ A TREATISE ON THE USE OF CRYSTAL GOLD. Gold is indispensable to commerce ; is one of the greatest, incentives to action and to enterprise ; is an emblem of royalty and power; is universally coveted, and is the father of many a crime ; it enriches our language with some of its most glowing adjectives, swells the remedial catalogue of medicines, and finds valuable uses throughout the whole range of the arts and sciences. But nowhere, and in no way, is it at the same time such a needful luxury and a continual comfort as in our Art. Here it realizes its highest end, and becomes exalted in its power to save, while it intimately mingles, and becomes permanently associated with living organs. Nature herself seems to have kindred feelings towards it, and permits it in such close proximity to her vital organs, that it sometimes nearly reposes upon blood-vessels, whose pulsations almost beat against it. At other times it harmlessly forms an arch under which delicately tissued nerves send many a subtle current of feeling. Gold ever has been, and probably ever will be, regarded as the best material for plugging and arresting carious teeth. Its capability of being attenuated into foil or finely divided crystals, and theSe afterwards of being consolidated into a united mass, its density when properly worked, its indestructibility, its color and nou-corrosive quality, render it superior to any other material for the purpose'of filling cavities of the teeth, where it will resist with impunity the ever varying and vitiating fluids of the mouth. The history, character, and uses of Gold Foil, are too well known to our Profession to requifte any detailed description, at this time. It is well known that its desirable qualities for our purpose, depend entirely upon its purity, and the manner hi, which it is manufactured—purity, however, always being an essential element of its goodness. \t is unne- cessary to refer to the cxcelle&c&iyMifc.qzticla^™ the purpose for which it is intended. In the hands or^hc skillful operator, it is daily restoring the perishing organs of the mouth to permanent health and usefulness. It has done; more towards elevating our Profession to its present high position than any other cause. I have no inclination, nor intention, of speaking disparagingly of it. All that could be done with it, has been Ion** since accomplished, and that is much, and far more than the Fathers in our Profession could have anticipated. In compariu«it with Crystal Gold, the objections to it must only be of a negative character. Slightly changing a familiar declaration, I may say, u not that I prize the one less, but the other more !" It is not that foil does not accomplish much, but that Crystal Gold accomplishes more. Foil, by skilful manip- ulation, may be made comparatively solid. Crystal Gold, by the same / 4 means, may be made absolutely so, becoming more dense even than coin. Foil is sometimes comparatively integrated ; that is, each part is resolved into the unity of the whole. Crystal Gold can always be so completely integrated, as to endure every test that coined gold can withstand. When the best foil stopping is removed from the tooth and crushed by a heavy lateral or sliding pressure, it is partially separated into irregular and laminated forms. This is very distinctly seen whenever the stopping is broken up in the mouth. The order, or manner of its disintegration, is as follows : The fluids of the mouth penetrate through and beneath the lamina, or around and about the borders of the pellets, gradually upheaving and disrupting the integrity of the whole. A gold stopping, when properly made, has the quality of oneness so complete, each ultimate particle being so thoroughly united and integrated into the whole, that it is no more likely to break up or sepa- rate from itself than any other equal bulk of pure solid gold. In case an angle or portion of it should be broken off, it would be the same as though an equal amount should be separated from any other piece of highly tempered gold. If desirable, the lost portion can be replaced ; if not, it may be filed and burnished down to a new surface, and left, without in the least endangering the remaining portion of the stopping. It is a fact well known to the Profession, that when foil is broken up into angles and formed into coils or pellets, it thereby often becomes so tempered, so hard and harsh, that it is worked only with great difficulty; the laminated structure of the gold is. so bent and angulated into thou- sands of arches, in-archings and bracings, as to resist a large force applied to the top of the mass, without materially breaking up the structure at the bottom. To obviate this, it is necessary to introduce the gold in smaller masses of less degree of density, and 40 forcibly work them together with the most delicate pointed instruments. Stopjpings made by our best artists, when placed under the microscope, will be found to have their inner surface entirely traced over with irregular, sinuous, concave groovings, extending froin the centre to its borders—the remains of the angular presentation of the foil to the sur- face of the cavity. When these semi-tubular "groovings arc too small to absorb the fluids of the mouth, their presence is not injurious ; but when larger, the ultimate disruption of the ..stopping is inevitable. Crystal Gold has a peculiar quality which permits it to be introduced into the cavity in comparatively large, masses, which may afterwards be thoroughly condensed in their placed When properly worked, it gives the sharpest impressionjDf all^e irregularities and most delicate markings of of the inner surface of tfrfr cavity, and absolutely insinuates itself into the texture of the tooth. This fact is easily demonstrated by the microscope. In using Crystal Gold, it will, however, be necessary in order to secure the highest degree of success, to take into consideration the nature and character of the article to be used ; wherein it differs from foil; and the peculiar manner of treatment it requires; for, in many respects, the system of manipulation which would secure the best foil stopping, would utterly fail of success when applied to Crystal Gold. Crystal Gold, as its name indicates, is made up of a combination of crystals of pure gold, so interlaced and interwoven that upon being sub- mitted to pressure, it readily welds into a solid mass. By leaving its upper surface rough in the act of filling, layer may may be built upon layer, until any desirable thickness is attained. As the arrangement of the crystals of the gold here mentioned, are in the most perfect condition l'or complete consolidation, it should be the study of the operator to avoid breaking up the formation, any more than is absolutely necessary, and, so far as possible, to give a direct pressure upon the gold, especially in the early part of the operation—bearing in mind that all wedge-shaped instruments should be dispensed with, in introducing the gold into the cavity, till after the gold is fixed to its place and partly condensed. The character of this gold so differs from that of foil, that even when introduced in masses, upon direct pressure being applied, it so yield* upon itself, that it may be readily carried to the remotest point of the cavity, and there consolidated against its wall. Unlike the smooth surface of foil, it presents myriads of angles to the opposing bone, and insinuates itself into the texture of the tooth ; for this reason, and also that the gold becomes constantly and absolutely solid as the operation advances, it is not necessary, as much as heretofore, to form cavities to ensure the retention of the gold. UENERAL DIRECTIONS. It will be well for those who have not had experience in the use of Crystal Gold, to confine their operations for a while, to that class of cavities which can be directly and easily approached : after they have acquired experience in the material, the tools and their manipulation,. lateral and more difficult cavities may be attempted. In case the gold should become wet during the operation of filling, thoroughly condense the gold already in the cavity, then burnish its surface and let the patient rest. In resuming the operation, brush out any crumbles of gold that may remain, dry the cavity and surface of gold with coils of tissue or bibulous paper; then, with a sharp-pointed condensing instrument, stipple over the entire face of the stopping, tak- ing advantage of all irregularities or undercuts of the surface, again dry the gold with paper, and proceed as before the accident—only taking care to work the first succeeding layer of gold thoroughly into the texture of that which underlies it. In case the gold loses its adhesive <|iiality by dampness or exposure, simply drying it over a spirit lamp, will restore it to its original condition. It is now more than two years since I commenced the use of Crystal Gold, manufactured by A. J. Watts & Co., of Utica. Since April last I have used it exclusively in my practice. Almost daily I meet with Crystal Gold stoppings, put into the teeth of my patients from the time of my first using it, and so far from my experience or observation having the effect of impairing my confidence in the new material, I daily congratulate myself upon being able to produce results which never could have been accomplished with foil. While all ordinary cavities may be filled with Crystal Gold, in a far superior manner to what it is possible to stop them with foil, it especially commends itself to an important class of valuable teeth, hitherto con- fessedly beyond the reach of foil or gold—in any form hitherto known— to save. I refer, 1st, to a large class of frail teeth, whose walls are so thin aud weak, as to be unable to resist the pressure of filling, and the lateral bearing of the plug necessary to its retention. And 2nd, to a class of teeth always deemed beyond the reach of art to save, namely, teeth without crowns, or of which but a fraction remains. Flitherto all of this first class of teeth, if treated at all, were filled with indifferent or perishable materials. The second class were almost 0 invariably suffered to be lost, When properly prepared, Crystal Gold may be effectually consolidated into cavities of the frailest teeth, without danger oi" fracture or breakage, in such a manner as to reproduce the entire lost substance of the teeth, and ensure the whole against further decay. It requires for its treatment an entirely different system of manipula- tion from that of foil. For this reason, and owing to peculiar qualities to which we will again allude, it is not only well adapted to all classes of decayed teeth, but eminently so to the particular class just referred to. The principal reason why a large share of frail teeth are not successfully filled with foil, is that the wedging and lateral pressure, necessary to its retention, and to secure a sufficiently solid plug, inevitably spread apart and break up the frail walls of the teeth. So that often, when a large stopping of foil has been introduced into a frail tooth, its walls are then more likely than ever to break, from the fact that an undue lateral pressure gives the foil a large leverage upon them, especially at the top of the walls, maintaining a continual tendency to spread and separate them from each other. These remarks apply with especial force to bicuspids and molars which have lost the anterior and posterior parts of their crowns, leaving only the buccal and lingual walls. Crystal Gold requires but little lateral pressure in its condensation. The very nature of its structure forbids it. Wedge-shaped instruments, especially if used before the gold is partly condensed, only break up its texture, and subject it to waste. It must be introduced in masses that are nearly covered by the presenting surface of the instrument used: with these, it should be carried to its place and there condensed, as far as possible : it should then be followed by smaller instruments, and by direct or perpendicular pressure, con- solidated. That portion of gold alone, which is immediately under the instrument, receives the pressure, which is not taken up and distributed throughout the whole plug as with foil—hence the several portions of gold, as they are successively carried to their place, require but little of the lateral pressure necessary for foil. As layer upon layer succeeds each other, they become absolutely solid and completely integrated into the general mass ; so that when the stopping is finished, its quality of unity is as complete as though it had been cast from the crucible. On account of this peculiar quality, by taking advantage of the inequalities of the external walls of their cav- ities, the frailest teeth may often be so overlaid and interlaced with the constantly solidifying gold, as to ha^e their walls effectually bound to- gether, not only securing them th&ir1 original position and condition, but fortifying them in it. In these cases, the remaining portions of the enamelled cusp become inlaid, as pearls are inlaid in gold. Frail teeth of this character, may not only have their opposite walls banded together by the inequalities of the external opening, but by their internal irregularities, which often- times appioach the character of dove-tailings, as will be seen by Figs. A, B, C, D, E, F, and G, hereinafter to be described. It often occurs to the Dentist, while extracting teeth which have only lost their crowns, and even roots of teeth which are well established in their places, that it is a matter of deep regret that such a superior and independent foundation for a tooth—one so pre- eminently beyond the reach of art to supply, should be destroyed, to be replaced, if replaced at all, by a clumsy fixture, covering a large portion of the palate, or, depending upon the adjoining teeth, insuring their t ultimate destruction. Fortunately, here again, Crystal Gold comes to our aid, and enables us, not only to replace and secure any remaining portion of the crown, but in many instances, to reproduce the entire crown itself. More than this, in case of the upper bicuspids, the entire crown has been reproduced in gold, with an enamel cap on the buccal surface, so as in all respects to represent, and take the place of the outer cusp. The method of operating on the three last mentioned kinds of teeth, will be mentioned in detail in this Treatise. The frail teeth spoken of will be ranged under the head of Class I. Molars and bicuspids with parts of, or without crowns, under the head of Class II. Bicuspids with the gold crowns and artificial cusps, under the head of Class III. For the benefit of those who are inexperienced in the use of Crystal Gold, I will undertake to give a more detailed description of the method of operating with it upon all classes of teeth, beginning with simple and ordinary cases, gradually approaching those more complex in their character, and ending with the special classes, arranged above, under the heads of Class I, II, and III. Before proceeding with a description of the method of operation, let us again consider the character of the material we are about to use, in order to supply ourselves with tools adapted to its peculiarities, as well as to impress ourselves with the system of manipulation it requires. Foil is thrust to its place and worked into its own texture, by a system of wedging. Crystal Gold packs ; it is adhesive and semi-plastic. As one layer succeeds another under the direction of proper instruments, it adheres to and integrates into the preceding layers, as legitimately and completely, as each added portion of clay under the hands of the artist, becomes resolved into the unity of the whole of the figure before him. So we must have tools which shall adapt themselves to its singular qualities. The adhesive and plastic nature of the material at once suggests instruments, approaching in character the modeling tools of the sculptor —some form of instrument by which we can take up the plastic material in broad masses, thin layers, attenuated strips or small particles, carry them to their place, and build upon and model, while we continually consolidate the whole. For the purpose of introducing the Crystal Gold to its place and partly consolidating it, instruments that are a kind of a cross between a plugging and a modeling tool, will be found to answer the above require- ments, and to be of indispensable usefulness to our purpose. Their forms may be modified or multiplied, according to the caprice, the genius or the needs of the operator. Several sizes of each will be required, gradually approximating to the smallest and most delicate. ^„ ^ No. 1 represents a broad-faced tool, slightly rounded at its edges, bent at an angle, the working end being serrated on all sides. The profile view shows that it is made thin, for the purpose of increas- ing its delicacy, as well as to admit of its being used for placing gold between ap- proximal and slightly separated surfaces. It is useful for many purposes, but chiefly for carrying masses of Crystal Gold to their place, and modeling and shaping Of? 2. 8 them into form. Instruments of this character, but of smaller size, are particularly useful in introducing gold into front teeth. No. 2 is a serrated instrument of the same general character, but broader and thicker, conical in form, and terminating in a point at its apex. It is an exceedingly fine modeling tool, and is especially useful in introducing large masses of gold into posterior cavities. No. 3. is also of the same general character, circular in shape, convex on one side, and flat on the other, invented by Dr. W. M. Hunter, of Cincinnati. In some parts of the operation, it is more useful than any other form. By rotating the instrument in the act of filling, the progress of consolidation is greatly facilitated. Its opposite or flat surface from its concave curve, is very useful in introdu- cing gold into posterior approximal cavities, or in all oper- ations where the operator must work toward himself. No. 4 is an instrument bent at a slight angle, flat on its upper surface, ftf»4. and terminating in a square point. The under surface is convex, gradually rounding at the sides until it meets the angle of the flat upper surface. Instruments of this character are more useful than others, for the reason that they combine all the advantages of three or four instruments in one, so that we can apply several different kinds of forces, without laying down the instrument. The upper and lower surfaces, the sides, and the ends, fur- nishing different and practical presentations, all of which are commanded by simply giving the instrument a part of a revolution. No. 5 represents an instrument slightly modified from the former, the W£?« chief difference arising from its having a concave groove cut £ m out immediately behind the convex presentation of the under surface, leaving the latter prominent, and giving the instru- ment a neck at this point, enabling the beaded prominence to pass for a short distance into the cavities of posterior approxi- mal presentations, while the curved neck of the instrument avoids the projecting angle of the tooth, which would other- wise interfere. It is very useful also in working the gold into the undercut angles of large molar cavities. These instruments may be bent to more acute angles or curves and diminished to the most delicate form with great advantage. With these modifications they are often very serviceable in filling cavities wse. No. «i is aflat thin, eoui-formed instrument, diverged to u ■slight angle, and ls particularly useful in introducing°gold be- tween the approximal surfaces of front teeth. It isTim useful m securing good joints about the borders of lar-e molar toppings, the point and edge of the instrument being&used for his purpose, with great advantage, care being taken durW he finishing operations of condensing or stopping, to so S the point of the instrument upon the stopping, t to have ' small bordering of gold intervene between itself^nd the enl- eled edge of the cavity to prevent fracturing it • 9 TW* ^ SSWfl. TTC2 MX. No. 7 represents a right and left instrument, with a parabolic, or rather, a wave-line curve, turned at an angle of about 35° from its shaft. Each side is serrated. It is very useful in filling all classes of approximal cavities, and was invented by Dr. R. Arthur, of Philadelphia, No. 8 is a serrated blade instrument, bent at various angles, and of different degrees of thickness, used principally in filling front and approximal cavities. xTiox, 2J-e than arionV ^ SVY* " ^^ niPidl*- We CUt }t into ***** of mote wzes and thickness, ,-ompn** some ol' the larger of these, so that their original thickness is reduced one hall; these we shall use' te make the first layer, to facilitate the operation, and ensure uT aAinst. breaking through the thin plate of bone that lie's between the bottom ol he cavity and the hvmg nerve beneath. With instrument Xo ] we Plac?" With V 1C r"Yr °°nderT, l,tttS' ^ '* t0' ™* tix Jt » Uh £t " !h N;,>114 a.nd Vve model ^d condense it into all the ine- qualities; then follow it with such fine instruments of the shape of No, 9 and 10 as circumstances shall require, taking especial care*to secure ^JTr^H bei?g aSSUred that tic c^re never sufm s from over attention to the circumference-imng as much pressure as the tool will bear, to ensure the perfect integration of the gold. Another and Set rs layer succeeds in the same order, until it is built up to the top of the cavity, taking care, whenever lateral pressure is required in the progress of the work, to give the lateral force direct. We fill the cavity flush, or over full, apply a condenser of the shape of No. 25, and finish as before described. If, on closing the mouth, any of the upper cusps strike upon the gold surface, we cut out the gold with a round graver, with burrs or drills, until the articulation is natural. Suppose in the case just considered, that the tooth had lost not only the internal portion of its crown, but that the whole anterior approximal wall was gone, together with a portion of each of its frontal cusps. It is desirable to reproduce the entire loss if possible. Most admirably docs Crystal Gold adapt itself to this purpose. The extraordinary and remarkable facility with which it can be built upon itself, and formed into independent shapes, in any required direction, is no less wonderful than satisfactory. In cases under consideration, where entire lost parts are being repro- duced, it is necessary to extend the gold a fraction beyond the boundary intended to be occupied, to compensate for condensation and the ne- cessary loss of substance in finishing. In the progress of building up, and modeling these independent shapes into form, pressure may be applied from time to time, upon the sides of the growing stopping, towards the centre of the tooth, with the same impunity that could be used upon the top. Especial pains should be taken to secure a good joint at its point of union on the sides of the tooth. Having introduced all the gold necessary for the operation, natural form is given it with files, gravers, &c., finishing as before with stones, crocus and burnisher. In filling the posterior approximal cavities of molar and bicuspid teeth, the usual preparations are made. Then, with instruments of the character of No. 1, we take up masses of gold on their convex or inner surfaces, of various thicknesses, adapted to the working spaces between the teeth, and carry them* to their places, following with Nos. 19, 5, 8 and 10, of various sizes and angles; as each mass follows the other, we are both pleased and surprised to find how readily each new installment of gold takes hold of, and clings to that whicflfcreceded it, the slightest contact often being sufficient to ensure this, thereby enabling us to with- draw the instrument, to model the gold in its place, or to get a new supply. After the cavity is a little over full, we pass over its surface again, and, looking well to its line of conjunction with the tooth, finish in the usual manner. Experience will soon enable us to make choice of the No. of gold best adapted to the various cases which may present themselves. The general rule is, to adapt the No. to the strength of the walls of the cavity, using the low Nos. for frail cavities, and the higher for the stronger ; though some use No. 1 for all cases, while others use No. 4 exclusively. As the space between the front teeth is usually contracted, by way of preparation for filling them, it is necessary to cut the gold into thin layers, nearly corresponding in diameter to the cavity to be filled, and sub-divide these into smaller pieces, for working into lateral points of the cavity. Everything being in readiness, with No. 1, 6 or 8, we take up one of the thin pellets of gold, and carefully direct it to its place between the teeth, and then towards and into the cavity to be filled, so far as it is possible to do so with the instrument in hand. As a usual thing, it is desirable to introduce another layer of gold in the same manner, before 14 proceeding to condense with smaller instruments. This, however, depends upon the thickness, as well as the No. of the gold. We now follow with Nos. 7 and 8, and follow up with any of the smaller forms of instruments used for foil, best adapted to the case. All of these, however, should be serrated until we come down to ultimate points. Various forms of these will be found in tin; cluster No. 2ti In introducing these smaller instruments into the cavities, par- ticular care should be taken to carry the points entirely over the whole line of their borders, especially consolidating them there. Layer succeeds layer, each one being taken up by the other, and integrated into the whole, continual care being taken to calk well the joints, until it is filled flush with the sides. We now pass over the whole surface with a small size of No. 8 or 21, or with a pointed instrument, then with a strong and steady hand, pass a blade burnisher several times over the surface of the gold, and let the patient rest. In resuming the operation, we trim down the gold with a thin file, follow this with tape, laden with pulverized arkansite, or the finest emery; pulverized pumice stone succeeds this in the same manner, to free the gold from all grit; then we finish with crocus, wash thoroughly, and the gold is ready for the burnisher, which we give a thin coating of castile soap before using, again we cleanse the surface of the gold, and we have a stopping, which for solidity, impermeability, unity and beauty, is far beyond any result ever produced with any other material. I will now consider the three classes of teeth beyond the reach of foil to save, referred to on page 7. There is a two-fold object in describing the extreme cl.isses of teeth under consideration. The first, is to illustrate the severe tests which Crystal Gold has been successfully subjected to, and the second, is to prove that if Crystal Gold will meet these extreme exigencies, which have never been suc- cessfully met before, it is abundantly qualified to meet all other cases in which foil can be used. The illustrations are all, with one exception, (Fig. Q,) taken from cases treated in the mouth—all but two of them, (Figs. Q and I,) being isjfce mouth at this time, where they have been from 9 to IS months ; each of which now presents the same appearance in all apparent particulars, that they did on the day of their completion. Fig- I5 Page 18> is a portrait a little " larger than life," of a tooth now in my possession, filled in January, 1854—was in daily use, and remained in the mouth until the latter part of the succeeding November, when it was extracted. It is a tooth whose entire crown, with the ex- ception of a small portion of one of the cusps, was reproduced in gold. It has the same external appearance now, which it had more than a year ago, and I have no doubt from analogies which will be herein presented, its internal character has remained unchanged. As before stated, it is now over two years since I adopted the Crystal Gold of A. J. Watts, in my practice. In an article published in the American Journal of Dental Science, of January, 185 I, I referred to several tests to which I subjected the Crystal Gold, it is with satisfaction that I now refer to another test—the test of time. By this my expectations are more than realized, not only in my own, but also in the practice of many of my friends, do I find the largest' and most complex stoppings continuing unchanged, even in the "lightest degree, after a trial of from a few months to more than two years. The L5 stoppings referred to comprise all classes, many of which could never have been made of foil. In my own practice, as much as three-fourths of the crowns were often reproduced in gold; in several instauces, the entire crowns, both of bicuspid find molars; and in numerous instances, frail bicuspids of the character already described, swelled the list; and yet, although many were filled in the early part of my experience with the Crystal Cold, in almost every instance success has been complete." In every case, with two exceptions, the surface of the stoppings remains unchanged, retaining their polish and density as at first; nor have the grinding surfaces of the stoppings, in any way, altered their shape; they being neither depressed by mastication, dissolved, or broken up, nor has there been any perceptible leakage or permeating of fluids of the mouth, into either the gold or joints between it and the tooth. It has been my custom for about a year and a half past, when some of the patients who belong to my " free list," have presented themselves to have a badly decayed tooth extracted, occasionally to relieve its present paiu by treatment, and then to fill it with Crystal Gold, paying them for their time, if it is a long operation, on condition that the tooth shall ultimately be mine. I have now something like 20 or 25 teeth of this kind out on probation. Of course, I do not expect to get but a part of them into my possession, but I have been so fortunate thus far as to obtain nine of them ; including three filled with the intention of having them remain, but which I was obliged to extract, one in consequence of a severe blow upon the face of the patient, another from scurvy and necrosis, and the other in consequence of exostosis. As might have been expected, these teeth were subjected to the most critical examination and the severest tests. Passing a pointed plugging instrument over the entire surface of each, especially at the joints, all were found to be perfect, save two. In each of these, the gold stopping for a small distance on its border, permitted the instrument to pass through its texture to near the bottom of the cavity, owing to the gold not having been completely consolidated at these points. Removing this porous part, the borders of the gold around it were found to be solid, and apparently impervious to the fluids of the mouth. The other case was similar to the one just described ; the soft portions were filled with water and mucous, and were easily removed, while the far larger portion remaining was dense, entire, and in all respects fully answering the pur- poses of a stopping, showing most manifestly that a uniform care and thoroughness in filling the tooth, would have produced a uniform and complete result. There can be little doubt, that in each of these in- stances, the stoppings would in time fail to preserve the teeth. I plead in extenuation that these were among my first efforts with Crystal Gold. My failure, however, no less than my subsequent success, proved what I could do and ought to have done. Cutting one of the filled teeth in two, 1 removed the stopping of gold. After heating it to redness, it was easily forged and rolled into plate, equal in all respects to any plate made of pure gold. To ascertain the structure and character of the gold within the cavity condensed against the bone and walls of the tooth, a frail bicuspid tooth, that had been worn in the mouth ten months, was selected. On chip- ping and cutting away nearly all of the surrounding walls of the tooth, leaving the stopping free and entire, it was gratifying to find that it was not only dense like the exposed surface, but that it presented an exact Hi reverse impression of all the inequalities of the walls of the tooth against which it reposed. Taking a bicuspid tooth in which a large stopping had been worn for about a year, with a thin wheel of soft iron laden with emery, the substance of the tooth and gold was cut entirely through, making two transverse sections, thus showing the completeness of the interior character of the gold, as well as its admirable calking or stop- ping quality, as manifested at the borders of the stopping, where it united with the tooth. Nothing could be more perfect, the stopping being equally solid throughout its whole texture. By the same process as above, a longitudinal section was made from grinding surface to apex, through a molar tooth, in which a larger Crys- tal Gold stopping had been worn in the mouth for fourteen months. The stopping was, and is, as completely integrated and solid, from centre to circumference, as though cast from'the crucible. Class I.— Frail teeth that have lost their anterior and posterior ap- jproximal surfaces, and have only their buccal and lingual walls remaining, (Figs. I) and F.) In these cases, the lateral pressure of the instruments in intro- ducing foil, and the expanded condition of it, after it is introduced, necessary to its retention and to secure a solid plug, are oftentimes sufficient to break the walls asunder ; and even when they do not give way, they are, as has already been intimated, more likely than ever to be broken off by lateral forces, from the fact that the foil has a large leverage upon the frail walls, especially at their extremities, giving them a continual tendency to separate from each other. Fig. A repre- FIG A ,sent3 a central, sectional view of one kind of this class. It will be perceived that the character of this tooth, admitted of its being excavated underneath the remaining portion of its grinding surface, so as to get a hold upon it, of a dovetail character. In filling such teeth, when the gold has accumula- ted to near these undercut places, it may be successfully intro- duced and packed within them, with instruments of the char- acter of Nos. 9, 10, and b, e, g,j, k, in Fig. 26. As the operation advances, the gold becomes constantly and absolutely solid, so that by the time the cavity is nearly full, the opposing cusps are firmly strapped together with the tie of gold that stretches from one to the other. Further security is given to the whole by letting the gold accumulate flush over the surface, thus inlaying the deflected, crowning angles of the tooth ; and also by packing the plastic gold over the irregular presentations of the external walls of the cavity, until it is flush, out to its original outline, as represented by Figs. C, E, and (1. The stopping may then be filed out on its grinding surface, until it has a free articulation, and then be finished in the usual manner. If the walls of the tooth are unusually frail, the operation will be strongly fortified and ensured against accident, by inserting one or two gold screws with a short protruding head into the bottom of the cavity, as indicated by the white lines in Figs. A and B. As the Crystal Gold is introduced and condensed in the cavity, it lays hold of and becomes solid around them ; so that their legitimate action and character is the same as though they passed through a piece of solid metal into the op- posing tooth, and screwed it firmly there, with the advantage of a perfect adaptation of the opposing substances to each other. Stoppings sue- 17 cessfully treated in this manner, become comparatively independent of the usual necessary requisites for their retention—since the little aid they receive from the frail opposing walls, is far more than compensated for by the great protection and peculiar advantages derived from the character of the material used, and its wonderful adaptibility to their exceeding frailty. The nerves of the class of teeth under consideration, are generally dead; in which case they should of course be removed, and their canals filled with gold, prior to commencing the operation upon the cavity proper. In the event the nerve is alive and healthy, smaller screws may be used, and inserted at an angle so diverted, as to avoid inter- ference with the more vital parts of the tooth. FIG. B. Fig. B is a tooth of the same general character with the one just described ; the opposing cusps are secured to each other by the cutting, or dip of the grinding surface. In some cases the layer of gold will necessarily be a thin one, especially if the tooth below articulates against it. Instances must be rare, however, in which the principle cannot be applied. Fig. C gives a sectional view of a tooth whose opposing walls are bound together by cutting out, and taking a of a perpendicular undercut of its inner walls. FIG. D. FIG. 0. dvantajre Fig. D. is the highest type of that class .of frail teeth men- tioned on pages 6 and 7. By natural and artificial means,an irreg- ular grooving has been formed around the borders of the eav- ity, between the outer and inner walls of the tooth, so FIG E. that when the plastic gold is solidified about them in the act of filling, it becomes insinuated and condensed into these depressions, thereby locking and banding the walls together. Fig. E gives a transverse sectional view of the same case, illustrating the manner in which the grooving and irregu- larities serve to bind the cusps together. If the walls are unu- sually thin, a screw may be inserted, as represented by Figs. A and B. FIG F Fig. F represents a superior molar tooth, of the same frail character as Fig. D. It is to be treated in the same way as the other, when, if skilfully secured, it has every prospect of remaining for many years, if not a life time, one of the most useful and cherished organs of the mouth. Fi / "> " —>-i/ 7 W