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diff --git a/26840.txt b/26840.txt new file mode 100644 index 0000000..e1d91a5 --- /dev/null +++ b/26840.txt @@ -0,0 +1,2752 @@ +The Project Gutenberg EBook of Tin Foil and Its Combinations for Filling +Teeth, by Henry L. Ambler + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Tin Foil and Its Combinations for Filling Teeth + +Author: Henry L. Ambler + +Release Date: October 8, 2008 [EBook #26840] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK TIN FOIL *** + + + + +Produced by Stephen Blundell and the Online Distributed +Proofreading Team at http://www.pgdp.net (This file was +produced from images generously made available by The +Internet Archive/American Libraries.) + + + + + + + + + + TIN FOIL + AND ITS + COMBINATIONS FOR FILLING TEETH. + + + BY + HENRY L. AMBLER, M.S., D.D.S., M.D., + Professor of Operative Dentistry and Dental Hygiene, in the Dental + Department of Western Reserve University. + Member of the American Dental Association; of the Ohio State Dental + Society; of the Northern Ohio Dental Association; + of the Cleveland City Dental Society. + + + PHILADELPHIA: + THE S. S. WHITE DENTAL MFG. CO., + LONDON: + CLAUDIUS ASH & SONS, Limited. + 1897 + + + + + Copyright, HENRY L. AMBLER, 1896. + All rights reserved. + Entered at Stationers Hall, London. + + +Transcriber's Note: + + Minor typographical errors have been corrected without note. Variant + and obsolete spellings, particularly chemical terms, have been + retained. The oe ligature is represented by [oe]. Subscript + characters are shown _{thus}, for example H_{2}O. + + + + +PREFACE. + + +Believing that sufficient and well-deserved prominence was not being +given to the use of tin foil and its combinations, the author decided to +present a brief historical resume of the subject, together with such +practical information as he possesses, before the profession in order +that it may have the satisfaction of saving more teeth, since that is +the pre-eminent function of the modern dentist. One object is to meet +the demand for information in regard to the properties and uses of tin +foil; this information has been sought to be given in the simplest form +consistent with scientific accuracy. The present use of tin is a case of +the "survival of the fittest," because tin was used for filling teeth +more than one hundred years ago. There is not a large amount of +literature upon the subject, and no single text-book has treated the +matter fully enough to answer the needs of both teacher and pupil. It is +difficult for the student to collect and harmonize from the many +different sources just the kind and amount of information required for +his special use. Perhaps this work will be of assistance to scientific +students and practical operators in the art of using tin foil, including +all who wish in compact form an explanation of the facts and principles +upon which the art is based. A good method to arouse in students an +interest in the use of tin foil is to have them use it in operative +technics, which is becoming an effective adjunct in every dental +college. By this means a great factor will be brought to bear, and the +result will be that hundreds of graduates every year will begin +practice better qualified to save teeth than if they had not known +whatever may be learned about this material. At the University of +Pennsylvania, Department of Dentistry, session 1896-97, out of the total +number of fillings made in the clinical department (fractions omitted) +55 per cent. were gold, 15 per cent. tin, 10 per cent. amalgam. This +shows that tin has some very strong friends in the persons of Professors +Darby and Kirk. + +The historical sketch of the development of the subject is arranged in +chronological order, and is given partly to show that some old ideas and +methods were good, and some obviously incorrect when viewed in the light +of more recent developments. Part of the history will be new to the +oldest members of the profession, and the younger ones will certainly +read it with interest. The work has been brought up to date by +considering all the properties and methods available. More names, good +opinions, and dates could have been given, but the writer believes that +what is herein presented is enough to thoroughly substantiate his own +opinions, experiments, and practical applications. Some of the +illustrations have been made especially for this work; the others have +been obtained through the courtesy of the owners. + +"Let not the foggy doctrine of the superiority of gold in all cases act +on progress as the old medieval superstitions acted on astronomy, +physiology, zoology. Truth sought after without misgiving, and the +humblest as well as the highest evidence taken in every case, and acted +on with skill and discrimination, will crown all with a high average of +success." + +It is hoped that what has been said in this volume will enable those who +study it to save more teeth, and stimulate them to make improvements on +the material and methods, doing much better than has been described or +suggested. + +CLEVELAND, OHIO, June, 1897. + + + + + "With soft and yielding lamina, and skill, + The practiced dental surgeon learns to fill + Each morbid cavity, by caries made, + With pliant tin; when thus the parts decayed + Are well supplied, corrosion, forced to yield + To conquering art the long-contested field, + Resigns its victim to the smiles of peace, + And all decay and irritation cease." + (_Solyman Brown._) + +The quantity of tin foil used measures the number of teeth saved with +_metals_ in any country during any historical period. + + + + +CONTENTS. + + + CHAPTER I. PAGE + Antiquity of Tin--Alchemistic Name--Medical Use--Where Found-- + Purity Obtained--Physical Characteristics 1 + + CHAPTER II. + History of the Use of Tin Foil, 1783-1844 7 + + + CHAPTER III. + History Continued, 1845-1895 15 + + CHAPTER IV. + Columbian Dental Congress--Opinions on Tin Foil--Reasons for + Using--Manufacture in United States--Number and Weight of + Foil--Cohesion--Good Qualities of Tin Foil--Temporary Teeth-- + Thermal Changes--Calcification--Chalky Teeth 27 + + CHAPTER V. + Discoloration of Tin--Decomposition of Food--Sulfids--Oxids-- + Galvanic, Therapeutic, and Chemical Action 40 + + CHAPTER VI. + White Caries--Gold and Tin as Conductors--Wearing Away of + Fillings--Poor Foil--Buccal Cavities--Number of Years + Fillings Last--Strips or Tapes for Filling--Number 10 Foil-- + Form of Cavities--Shields--Matrices--Condensing--Finishing-- + Cervical Margins--Filling Anterior Teeth--Lining with Gold 49 + + CHAPTER VII. + Filling, part Tin, part Gold--Cervical Margin Liable to + Caries--Electrolysis--Hand Pressure--Hand Mallet--Tapes and + Ropes Compared--Manner of Preparing Foil--Starting the + Filling--Cylinders--Mats--Facing and Repairing--Tin + Shavings--Dr. Herbst's Method--Fees 56 + + CHAPTER VIII. + Dr. Robinson's Fibrous and Textile Metallic Filling--Tin and + Gold combined (Tg), Methods of Preparing and Using--Lining + Cavities with Tin--Tin and Amalgam--Plastic Tin--Stannous + Gold--Crystal Tin--Filling Root-Canals--Tin and Watts's + Sponge Gold--Capping Pulps 66 + + CHAPTER IX. + Temporary Fillings--Sensitive Cavities--Integrity--Tin with + Sponge, Fibrous, and Crystallized Gold--Tin at Cervical + Margin--Filling Completed with Gold--Gutta-Percha and Tin-- + Occlusal Cavities with Tin and Gold--Comparison of Gold with + Tin--Wedge-shaped Instruments--Old Method of Using Rolls, + Ropes, Tapes, or Strips--Later Method--Filling with Compact + and Loose Balls--Cylinder Fillings--Operative Technics 91 + + + + +CHAPTER I. + + +Moses, who was born 1600 B.C., mentions tin, and history records its use +500 B.C., but not for filling teeth; much later on, the Ph[oe]nicians +took it from Cornwall, England, to Tyre and Sidon. + +The alchemistic name for tin is Jove, and in the alchemistic +nomenclature medicinal preparations made from it are called Jovial +preparations. + +Hindoo native doctors give tin salts for urinary affections. Monroe, +Fothergill, and Richter claim to have expelled worms from the human +system, by administering tin filings. + +Blackie, in "Lays of Highlands and Islands," referring to tin as money, +says,-- + + "And is this all? And have I seen the whole + Cathedral, chapel, nunnery, and graves? + 'Tis scantly worth the tin, upon my soul." + +"Tin-penny."--A customary duty formerly paid to the tithingmen in +England for liberty to dig in the tin-mines. + +In 1846, Tin (Stannum, symbol Sn) was found in the United States only at +Jackson, N. H. Since then it has been found, to a limited extent, in +West Virginia and adjoining parts of Ohio, North Carolina, Utah, and +North Dakota. The richest tin mines of the world, however, are in +Cornwall, England, which have been worked from the time of the +Ph[oe]nician discovery. + +The tin which is found in Malacca and Banca, India, is of great purity, +and is called "Straits Tin" or "Stream Tin." It occurs in alluvial +deposits in the form of small rounded grains, which are washed, stamped, +mixed with slag and scoriae, and smelted with charcoal, then run into +basins, where the upper portion, after being removed, is known as the +best refined tin. Stream tin is not pure metallic tin, but is the result +of the disintegration of granitic and other rocks which contain veins of +tinstone. Banca tin is 99.961 parts tin, 0.019 iron, 0.014 lead in 100 +parts; it is sold in blocks of 40 and 120 pounds, and a bar 0.5 meter +long, 0.1 broad, 0.005 deep can be bent seventy-four times without being +broken. Subjected to friction, tin emits a characteristic odor. + +Tin in solution is largely used in electro-metallurgy for plating. Pure +tin may be obtained by dissolving commercial tin in hydrochloric acid, +by which it is converted into stannous chlorid; after filtering, this +solution is evaporated to a small bulk, and treated with nitric acid, +which converts it into stannic oxid, which in turn is thoroughly washed +and dried, then heated to redness in a crucible with charcoal, producing +a button of tin which is found at the bottom of the crucible. + +Pure tin may be precipitated in quadratic crystals by a slight galvanic +current excited by immersing a plate of tin in a strong solution of +stannous chlorid; water is carefully poured in so as not to disturb the +layer of tin solution; the pure metal will be deposited on the plate of +tin, at the point of junction of the water and metallic solution. + +In the study of tin as a material for filling teeth, we have deemed it +expedient to consider some of its physical characteristics, in order +that what follows may be more clearly understood. + +Tin possesses a crystallized structure, and can be obtained in +well-formed crystals of the tetragonal or quadratic system (form right +square prism), and on account of this crystalline structure, a bar of +tin when bent emits a creaking sound, termed the "cry of tin;" the purer +the tin the more marked the cry. + +The specific gravity is 7.29; electrical state positive; fusing point +442 deg. F.; tensile strength per square inch in tons, 2 to 3. Tensile +strength is the resistance of the fibers or particles of a body to +separation, so that the amount stated is the weight or power required +to tear asunder a bar of pure tin having a cross-section of one square +inch. + +Tenacity: Iron is the most tenacious of metals. To pull asunder an iron +wire 0.787 of a line in diameter requires a weight of 549 lbs. To pull +asunder a gold wire of the same size, 150 lbs.; tin wire, 34 lbs.; gold +being thus shown to be more than four times as tenacious as tin. +(Fractions omitted.) + +Malleability: Pure tin may be beaten into leaves one-fortieth of a +millimeter thick, thus requiring 1020 to make an inch in thickness. +Miller states that it can be beaten into leaves .008 of a millimeter +thick, thus requiring 3175 to make an inch in thickness. Richardson says +that ordinary tin foil is about 0.001 of an inch in thickness. + +If the difficulty with which a mass of gold (the most malleable of +metals) can be hammered or rolled into a thin sheet without being torn, +be taken as one, then it will be four times as difficult to manipulate +tin into thin sheets. + +Ductility: If the difficulty with which gold (the most ductile of +metals) can be drawn be taken as one, then it will be seven times as +difficult to draw tin into a wire. At a temperature of 212 deg. it has +considerable ductility, and can be drawn into wire. + +Among the metals, silver is the best conductor of heat. If the +conductivity of silver be taken as 100, then the conducting power of +gold would be 53.2; tin, 14.5; gold being thus shown to be nearly four +times as good a conductor of heat as tin. Among the metals, silver is +the best conductor of electricity. If its electrical conductivity be +taken at 100, then the conducting power of gold would be 77.96; tin, +12.36; gold being thus shown to be more than six times as good a +conductor of electricity as tin. + +Resistance to air: If exposed to dry, pure air, tin resists any change +for a _great_ length of time, but if exposed to air containing moisture, +carbonic acid, etc., its time resistance is reduced, although even then +it resists corrosion much better than copper or iron. + +As to linear expansion, when raised from 32 deg. to 212 deg. F., aluminum +expands the most of any of the metals. Taking its expansion as 1, that +of tin would be 3, _i.e._, aluminum expands three times as much as tin. +(Dixon, "Vade Mecum.") + +Solids generally expand equally in all directions, and on cooling return +to their original shape. Within certain limits, metals expand uniformly +in direct proportion to the increase in temperature, but the rate of +expansion varies with different metals; thus, under like conditions, tin +expands nearly twice (1-3/5) as much as gold, but the _rate_ of +expansion for gold is nearly twice (1-7/10) that of tin. + +The capacity for absorbing heat varies with each metal; that of gold is +about twice (1-3/4) that of tin. + +Tin has a scale hardness of about 4, on a scale of 12 where lead is +taken as the softest and platinum the hardest. (Dixon, "Vade Mecum.") + +Tin has a scale hardness of about 2. (Dr. Miller.) + +To fuse a tin wire one centimeter in diameter requires a fusing current +of electricity of 405.5 amperes. Up to 225 deg. C., the rise in resistance +to the passage of an electric current is more rapid in tin than in gold. +In some minerals the current follows the trend of the crystals. + +Gold wire coated with tin, and held in the flame of a Bunsen burner, +will melt like a tin wire. At 1600 deg. to 1800 deg. tin boils and may be +distilled. + + + + +CHAPTER II. + + +The largest and most complete dental library in the world is owned by +Dr. H. J. McKellops, of St. Louis. Upon his cheerful invitation, the +writer visited that "Mecca," and through his kindness and assistance a +complete search was made, which resulted in obtaining a great portion of +the following historical facts with reference to the use of tin in +dentistry: + +"In 1783 I stopped a considerable decay in a large double under tooth, +on the outside of the crown or near the gums, with fine tin foil, which +lasted for a good number of years." ("A Practical and Domestic Treatise +on Teeth and Gums," by Mr. Sigmond, Bath, England, 1825.) + +"Fine tin foil or gold leaf may be injected into a cavity successfully, +and retained securely for many years." (Joseph Fox, Dover, England, +1802.) + +"The statement has been made several times that tin foil was used in the +United States for filling teeth as early as 1800, at which time +dentistry began to be cultivated particularly as a science and art, and +was beginning to be regarded as of more importance than it formerly had +been. The writer has not found any record of its use in this country +earlier than 1809. Tin may often be employed with entire confidence. I +have seen fillings forty-one years old (made in 1809) and still perfect. +Several molars had four or five plugs in them, which had been inserted +at different periods during the last half-century. I prefer strips cut +from six sheets laid upon each other. If the foil is well connected, the +cut edges will adhere firmly; if they do not, the foil is not fit for +use." (Dr. B. T. Whitney, _Dental Register of the West_, 1850.) First +reference to the fact that tin is adhesive. + +"Tin is desirable in all unexposed cavities. It has a stronger affinity +for acetic, citric, tartaric, malic, lactic, and nitric acids than the +tooth has: a good material where the secretions are of an acid +character, it is better that the filling should waste away than the +tooth. One cavity in my mouth was filled with gold, decay occurred, the +filling was removed; cavity filled with oxychlorid, which produced pain; +filling removed; cavity filled with gutta-percha, still experienced +pain; filling removed; cavity filled with tin, and pain ceased in an +hour. A tin filling was shown in New York which was sixty years old; +made in 1811." (Dr. E. A. Bogue, _British Journal of Dental Science_, +1871.) + +"I have lately been removing tin pluggings (the juices of the mouth +having oxidated and dissolved away the metal, so as to expose the teeth +to decay) from teeth which I plugged fifteen years ago (1818) for the +purpose of re-stopping with gold, and have in almost every instance +found the bone of the tooth at the bottom of the pluggings perfectly +sound and protected from decay." (J. R. Spooner, Montreal, 1833.) + +In 1800 the number of dentists in the United States was about one +hundred, and many of them were using tin foil for filling teeth. + +In 1822 tin was employed by the best dentists, with hardly an exception; +it grew in favor, especially for large cavities in molars, and for a +cheaper class of operations than gold, but tin was not generally used +until 1830. ("History of Dental and Oral Science in America.") + +"Lead, tin, and silver corrode and become more injurious than the +original disease, and will in every case ultimately prove the cause of +destruction to the tooth, which might have been preserved by proper +treatment." (Leonard Koecker, 1826, and "New System of Treating the +Human Teeth," by J. Paterson Clark, London, 1829 and 1830.) + +"Tin in situations out of reach of friction in mastication, as between +two teeth, is like the tooth itself apt to be decomposed by acidity +unless kept very clean." ("Practical and Familiar Treatise on Teeth and +Dentism," J. Paterson Clark, London, 1836.) Refer to what the same +author said in 1829. + +"Tin is used as a plugging material." ("The Anatomy, Physiology, and +Diseases of the Teeth," by Thomas Bell, F.R.S., London, 1829.) + +"Silver and tin foil, although bright when first put in a cavity, very +soon change to a dark hue, resembling the decayed parts of the teeth +which are of a bluish cast; besides this, they are not sufficiently pure +to remain in an unchanged state, and frequently they assist in the +destruction of a tooth instead of retarding it." ("Familiar Treatise on +the Teeth," by Joseph Harris, London, 1830.) + +"Tin is objectionable on account of rapid oxidation and being washed by +the saliva into the stomach, as it may materially disorder it; the +filling becomes so reduced that the cavity in which it has been inserted +will no longer retain it, and acid fruits influence galvanic action." +("Every Man his Own Dentist," Joseph Scott, London, 1833.) + +In 1836 Dr. Diaz, of Jamaica, used tin foil for filling teeth. + +"Gold is now preferred, though tin, from its toughness when in the leaf, +is perhaps the most suitable. Americans are superior to British in +filling." ("Plain Advice on Care of the Teeth," Dr. A. Cameron, Glasgow, +1838.) + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +"Tin foil is used for filling teeth." (S. Spooner, New York, 1838, +"Guide to Sound Teeth.") + +In 1838 Archibald McBride, of Pittsburg, Pa., used tin for filling +cavities of decay. + +The following facts were learned from Dr. Corydon Palmer: E. E. Smith, +who had been a student of John and William Birkey, in Philadelphia, came +to Warren, Ohio, in 1839, and among other things made the first gold +plate in that part of the country. In operating on the anterior teeth, +he first passed a separating file between them, excavated the cavity, +and prepared the foil, _tin_ or gold, in tapes which were cut +transversely, every eighth of an inch, about three-quarters of the way +across. Fig. 1 shows the size of tape and the manner of cutting. With an +instrument (Fig. 2) he drew the foil in from the labial surface, using +such portion of the tape as desired. + +The instrument from which the illustration was made was furnished by Dr. +Palmer, and is shown full size. Instruments for use on posterior teeth +were short and strong, with as few curves as possible; no right and left +cutters or pluggers were used, and none of the latter were serrated, but +had straight, tapering round points, flat on the ends, and of suitable +size to fill a good portion of the cavity. He used what was termed +Abbey's chemically pure tin foil, forcing it in hard, layer upon +layer,--as he expressed it, "smacked it up." In this manner he made tin +fillings that lasted more than thirty years. + +In 1839 Dr. Corydon Palmer filled teeth with tin foil, also lined +cavities with gold and filled the remainder with tin. In the same year +he filled crown (occlusal) cavities one-half full with tin and the other +half with gold, allowing both metals to come to the surface, on the same +plan that many proximal cavities are now filled. (See Fig. 3, showing +about one-half of the cavity nearly completed with tin cylinders. The +same plan was followed when strips, or ropes, were used.) + +"I filled cavities about two-thirds full with tin, and finished with +gold." (S. S. Stringfellow, _American Journal of Dental Science_, 1839.) + +"Tin foil is greatly used by some American dentists, but it is not much +better than lead leaf." ("Surgical, Operative, and Mechanical +Dentistry," L. Charles De Londe, London, 1840.) + +[Illustration: FIG. 3.] + +"In 1841 there were about twelve hundred dentists in the United States, +many of whom were using tin, and there are circumstances under which it +may be used not only with impunity, but advantage, but it is liable to +change." (Harris.) + +"I put in tin fillings, and at the end of thirty years they were badly +worn, but there was no decay around the margins." (Dr. Neall, 1843.) + +In 1843 Dr. Amos Westcott, of Syracuse, N. Y., filled the base of large +cavities with tin, completing the operation with gold. + +"Tin is used in the form of little balls, or tubes, but folds are +better; introduce the metal gradually, taking care to pack it so that it +will bear equally upon all points; the folds superimpose themselves one +upon the other; thus we obtain a successive stratification much more +exact and dense, and it is impossible there can be any void." ("Theory +and Practice of Dental Surgery," J. Lefoulon, Paris, 1844.) + + + + +CHAPTER III. + + +"Besides gold, the only material which can be used with any hope of +permanent success is tin foil. Some dentists call it _silver_, and a +tooth which cannot be filled with it cannot be filled with anything else +so as to stop decay and make it last very long. It can be used only in +the back teeth, as its dark color renders it unsuitable for those in +front. When the general health is good, and the teeth little predisposed +to decay, this metal will preserve them as effectually perhaps as gold; +but where the fluids of the mouth are much disordered it oxidizes +rapidly, and instead of preserving the teeth rather increases their +tendency to decay." (Dr. Robert Arthur, Baltimore, 1845, "A Popular +Treatise on the Diseases of the Teeth.") + +The false idea that a patient must have good health, normal oral fluids, +and teeth little predisposed to decay, or else if filled with tin the +decay would be hastened, originated with a German or English author, and +has been handed down in works published since early in 1800. It even +crept into American text-books as late as 1860, the authors of which now +disbelieve it. + +"Tin undergoes but little change in the mouth, and may be used with +comparative safety." ("Surgical, Mechanical, and Medical Treatment of +the Teeth," James Robinson, London, 1846.) + +"Tin is soft, and can be easily and compactly introduced, but it is more +easily acted on by the secretions of the mouth than gold and is less +durable, but in the mouth of a healthy person _it will last for years_. +Still, inasmuch as it cannot be depended on in _all_ cases, we are of +the opinion that it should _never_ be employed." ("The Human Teeth," +James Fox, London, 1846.) + +The italics are ours. Every metal has a limited sphere of usefulness, +and it should not be expected that tin will contend single-handed +against all the complicated conditions which caries presents. + +"Of all the cheaper materials, I consider tin the best by far, and +regard its use fully justifiable in deciduous teeth and in large +cavities, as it is not every man who can afford the expense of nine +leaves of gold and four hours of labor by a dentist on a single tooth." +(Dr. Edward Taylor, _Dental Register of the West_, 1847.) + +"I consider tin good for any cavity in a chalky tooth: it will save them +better than anything else." (Dr. Holmes, 1848.) + +"Tin can be used as a temporary filling, or as a matter of economy. It +may be rendered impervious to air and dampness, but it corrodes in most +mouths, unless it comes in contact with food in chewing, and then it +rapidly wears away; it does not become hard by packing or under +pressure, and that it forms a kind of a union with the tooth is +ridiculous." (Dr. J. D. White, 1849, _Dental News Letter_.) + +"A tin plug will answer a very good purpose in medium and large cavities +for six years. Much imposition has been practiced with it, and it is not +made as malleable as it should and can be. An inferior article is +manufactured which possesses brilliancy and resembles silver. This is +often passed off for silver foil. No harm comes from this deception +except the loss of the amount paid above the price for tin; but even +this inferior tin foil is better than silver." ("The Practical Family +Dentist," Dewitt C. Warner, New York, 1853.) + +"Tin made into leaves is employed as a stopping material; with +sufficient experience it can be elaborated into the finest lines and +cracks, and against almost the weakest walls, and teeth are sometimes +lost with gold that might have been well preserved with tin. I saw an +effective tin stopping in a tooth of Cramer's, the celebrated musical +composer, which had been placed there thirty-five years ago by Talma, +of Paris." ("The Odontalgist," by J. Paterson Clark, London, 1854.) + +Refer to what the same author said in 1836. + +"Tin is the best substitute for gold, and can often be used in badly +shaped cavities where gold cannot." (Prof. Harris, 1854.) + +"Tin is better than any mixture of metals for filling teeth." (Professor +Tomes, London, 1859.) + +In 1860 a writer said that "such a change may take place in the mouth as +to destroy tin fillings which had been useful for years, and that tin +was not entirely reliable in any case; it must not be used in a tooth +where there is another metal, nor be put in the bottom of a cavity and +covered with gold, for the tin will yield, and when fluids come in +contact with the metals, chemical action is induced, and the tin is +oxidized. Similar fillings in the same mouth may not save the teeth +equally well. Filling is predicated on the nature of decay, for only on +correct diagnosis can a proper filling-material be selected." + +Reviewing the foregoing statement, we believe that a change may take +place in the mouth which will destroy gold fillings (or the +tooth-structure around them) much oftener than those of tin. It is now +every-day practice to put tin into the same tooth with another metal; if +the bottom of a cavity is filled with tin properly packed, it will not +yield when completed with gold, and if the gold is tight, the oral +fluids cannot come in contact with both metals and produce chemical +action or oxidation; similar fillings of gold in the same mouth do not +save the teeth equally well. Should we expect more of tin in this +respect, or discard it because it is not always better than gold? + +In Article V of the "New Departure Creed," Dr. Flagg says, "Skillful and +scrupulous dentists fill with tin covered with gold, thereby preventing +decay, pulpitis, death of the pulp, and abscess, and thus save the +teeth." + +In 1862 Mr. Hockley, of London, mentions tin for filling, and the same +year Dr. Zeitman, of Germany, recommended it as a substitute for gold, +particularly for poor people. + +"Is tin foil poisonous? If not, why are our brethren so reluctant to use +it? Is it nauseous? If not, why not employ it? Will it not preserve the +teeth when properly used? Then why not encourage the use of it? Does its +name signify one too common in the eyes of the people, on account of its +daily use in the tin shops, or do patients murmur when the fee is +announced, because it is nothing but tin? Is it not better than amalgam, +although the patient may believe it less costly? Eleven good plugs, +twenty-nine years old, in one mouth demonstrates that tin will last as +long as gold in many cases." (F. A. Brewer, _Dental Cosmos_, 1863.) + +"So much tin foil is used for personal and domestic purposes that the +following is important: Ordinary tin foil by chemical analysis contained +88.93 per cent. of lead; embossed foil, 76.57 per cent.; tea foil, 88.66 +per cent.; that which was sold for the pure article, 34.62 per cent. Tin +foil of above kind is made by inclosing an ingot of lead between two +ingots of tin, and rolling them out into foil, thus having the tin on +the outside of the lead." (Dr. J. H. Baldock, _Dental Cosmos_, 1867.) + +The author used tin foil for filling the teeth of some of his +fellow-students at the Ohio College of Dental Surgery in 1867. + +"Amalgam should never be used in teeth which can be filled with tin, and +most of them can be." (Dr. H. M. Brooker, Montreal, 1870.) + +"I have used tin extensively, and found it more satisfactory than +amalgam. Dentists ignore tin, because it is easier to use amalgam, less +trouble. This is not right. If your preceptor has told you that amalgam +is as good as tin, and he thinks so, let him write an article in its +defense. Not one dentist in ten who has come into the profession within +the last ten years knows how to make a tin filling, and only a few of +the older ones know how to make a _good_ one." (Dr. H. S. Chase, +_Missouri Dental Journal_, 1870.) + +"Among the best operators a more general use of tin would produce +advantageous results, while among those whose operations in gold are not +generally successful an almost exclusive use of tin would bring about a +corresponding quantum of success to themselves and patients, as against +repeated failures with gold. The same degree of endeavor which lacked +success with gold, if applied to tin would produce good results and save +teeth. A golden shower of ducats realized for gold finds enthusiastic +admirers, but a dull gray shower for tin work is not so admirable, even +though many of the teeth were no better for the gold as gold, nor so +well off in the ultimate as with tin." (Dr. E. W. Foster, _Dental +Cosmos_, 1873.) + +In 1873 Dr. Royal Varney said, "I am heartily in favor of tin; it is too +much neglected by our first-class operators." + +"Tin stops the ends of the tubuli and interglobular spaces which are +formed in the teeth of excessive vascular organization; if more teeth +were filled with tin, and a smaller number with futile attempts with +gold, people would be more benefited." (Dr. Castle, _Dental Cosmos_, +1873.) + +"If cavities in teeth out of the mouth are well filled with tin, and put +into ink for three days, no discoloration of the tooth (when split open) +can be seen." (W. E. Driscoll, _Dental Cosmos_, 1874.) + +"Tin makes an hermetical filling, and resists the disintegrating action +of the fluids of the mouth. If an operator can preserve teeth for +fifteen dollars with tin, which would cost fifty dollars with gold, +ought he not to do so? Upon examination of the cavities from which +oxidized plugs have been removed, these oxids will be found to have had +a reflex effect upon the dentin; the walls and floors will be discolored +and thoroughly indurated, and to a great degree devoid of sensitiveness, +although they were sensitive when filled. Tin is valuable in case of +youth, nervousness, impatience, high vitality of dentin, low +calcification, and low pecuniosity." (Dr. H. Gerhart, _Pennsylvania +Journal of Dental Science_, 1875.) + +"Tin Foil for Filling Teeth." Essay by Dr. H. L. Ambler, read before the +Ohio State Dental Society. (_Dental Register of the West_, 1875.) + +"Some say that if tin is the material the cavity must be filled with, +that it must be filled entirely with it, but advanced teachings show +differently." (Dr. D. D. Smith, _Dental Cosmos_, October, 1878.) + +"Frail teeth can be saved better with tin than with gold. I never saw a +devitalized pulp under a tin filling." (Dr. Dixon, _Dental Cosmos_, May, +1880.) + +"Tin may be used as a base for proximate fillings in bicuspids or +molars, in third molars, in children's permanent molars, in the +temporary teeth, and in any cavity where the filling is not +conspicuous." (Dr. A. W. Harlan, _Independent Practitioner_, 1884.) + +"Tin in blocks, mats, and tapes is used like non-cohesive gold foil, but +absence of cohesion prevents the pieces from keeping their place as well +as the gold." ("American System of Dentistry," 1887.) + +This is virtually saying that there is cohesion of non-cohesive gold, +and that for this reason it keeps its place better than tin. It has +always been supposed that there was no cohesion of layers of +non-cohesive gold, and as the tin is used on the non-cohesive plan, +therefore one keeps its place as well as the other. We claim that +generally in starting a filling, tin will keep its place better than +cohesive or non-cohesive gold, because it combines some of the +cohesiveness of the former with the adaptability of the latter. + +"Tin will save teeth in many cases as well or better than gold. Put a +mat of tin at the cervical wall of proximate cavities in molars and +bicuspids, and it makes a good filling which has a therapeutic effect on +tooth-structure that prevents the recurrence of caries, probably because +the infiltration of tin oxid into the tubuli is destructive to animal +life. Where the filling is not exposed to mechanical force, there is no +material under heavens which will preserve the teeth better." (Dr. +Beach, _Dental Cosmos_, 1889.) + +"I extracted a tooth in which I found a cavity of decay which had +extended toward a tin filling, but stopped before reaching it; on +examining the tooth-structure between the new cavity and the tin +filling, it was found to be very hard, indicating apparently that there +had been some action produced by the presence of the tin." (Dr. G. +White, _Dental Cosmos_, 1889.) + +"Pure tin in form of foil is used as a filling and also in connection +with non-cohesive gold." (Mitchell's "Dental Chemistry," 1890.) + +"Tin ranks next to gold as a filling-material." (Essig's "Dental +Metallurgy," 1893.) + +"Tin is good for children's teeth, when gold or amalgam is not +indicated. It can be used in cavities which are so sensitive to thermal +changes as to render the use of gold or amalgam unwise, but it can only +be used in cavities with continuous walls, and should be introduced in +the form of cylinders or ropes, with wedge-shaped pluggers having sharp +deep serrations, thus depending upon the wedging or interdigitating +process to hold the filling in the cavity." ("Operative Technics," Prof. +T. E. Weeks, 1895.) + +"Tin for filling teeth has been almost superseded by amalgam, although +among the older practitioners (those who understand how to manipulate +it) tin is considered one of the best, if not the very best metal known +for preserving the teeth from caries. In consequence of its lack of the +cohesive property, it is introduced and retained in a cavity upon the +wedging principle, the last piece serving as a keystone or anchor to the +whole filling. Each piece should fill a portion of the cavity from the +bottom to the top, with sufficient tin protruding from the cavity to +serve for thorough condensation of the surface, and the last piece +inserted should have a retaining cavity to hold it firmly in place. The +foil is prepared by folding a whole or half-sheet and twisting it into a +rope, which is then cut into suitable lengths for the cavity to be +filled." (Frank Abbott, "Dental Pathology and Practice," 1896.) + +"Forty-three years ago, for a young lady fourteen years of age, I +filled with non-cohesive gold all the teeth worth filling with this +metal; the rest I filled with tin. Three years after that there was not +a perfect gold filling among the whole number, and yet the tin fillings +were just as good as when made. The explanation as to why the tin +fillings lasted so much longer than the gold ones was, that there must +have been something in the tin that had an affinity for the teeth and +the elements that formed the dentin, by which some compound was formed, +or else it must have been in the adaptation." (Dr. H. Gerhart, _Dental +Cosmos_, January, 1897.) + + + + +CHAPTER IV. + + +At the World's Columbian Dental Congress, held in Chicago, August, 1893, +the author presented an essay on "Tin Foil for Filling Teeth." + +During the discussion of the subject, the following opinions were +elicited: + +Dr. E. T. Darby: "I have always said that tin was one of the best +filling-materials we have, and believe more teeth could be saved with it +than with gold. I have restored a whole crown with tin, in order to show +its cohesive properties; the essayist has paid a very high and worthy +tribute to tin." + +Dr. R. R. Freeman: "I have used tin foil for twenty-five years, and know +that it has therapeutic properties, and is one of the best +filling-materials, not excepting gold." + +Madam Tiburtius-Hirschfield: "I heartily indorse the use of tin, and +have tested its cohesive properties by building up crowns." + +Dr. A. H. Brockway: "I am a strong believer in the use of tin, on +account of its adaptability, and the facility with which saving fillings +can be made with it." + +Dr. Gordon White: "After having used tin for nine years, I claim that +it is the best filling-material that has been given to our profession." + +Dr. C. S. Stockton: "Tin is one of the best materials for saving teeth, +and we should use it more than we do." + +Dr. James Truman: "I use tin strictly upon the cohesive principle, and +would place it in all teeth except the anterior ones, but would not +hesitate to fill these when of a chalky character." + +Dr. Corydon Palmer: "For fifty-four years I have been a firm advocate of +the use of tin, and I have a filling in one of my teeth which is forty +years old." + +Dr. William Jarvie: "I rarely fill a cavity with gold for children under +twelve years of age that I want to keep permanently, but use tin, and in +five or ten years, more or less, it wears out. Still, it can easily be +renewed, or if all the tin is removed we find the dentin hard and firm. +The dentist is not always doing the best for his patients if he does not +practice in this way." + +Dr. C. E. Francis: "I have proved positively that tin foil in good +condition is cohesive, and my views have been corroborated by dentists +and chemists." + +Dr. James E. Garretson: "Tin foil is cohesive, and can be used the same +as gold foil, and to an extent answers the same purpose." + +Dr. C. R. Butler: "Tin is cohesive and makes a first-class saving +filling." + +Dr. W. C. Barrett: "Tin is as cohesive as gold, and if everything was +blotted out of existence with which teeth could be filled, except tin, +more teeth would be saved." + +Dr. L. D. Shepard: "Tin possesses some antiseptic properties for the +preservation of teeth that gold does not." + +Dr. W. D. Miller: "I use tin foil in cylinders, strips, and ropes, on +the non-cohesive plan, but admit that it possesses a slight degree of +cohesiveness, and when necessary can be built up like cohesive gold by +using deeply serrated pluggers." + +Dr. Benjamin Lord says, "It is said that we know the world, or learn the +world, by comparison. If we compare tin foil with gold foil, we find +that the tin, being softer, works more kindly, and can be more readily +and with more certainty adapted to the walls, the inequalities, and the +corners of the cavities. + +"We find also that tin welds--mechanically, of course--more surely than +soft gold, owing to its greater softness; the folds can be interlaced or +forced into each other, and united with more certainty, and with so +much security that, after the packing and condensing are finished, the +mass may be cut like molten metal. + +"I contend moreover that for contouring the filling or restoring the +natural shape of the teeth, where there are three walls remaining to the +cavity, tin is fully equal to gold, and in some respects even superior; +as tin can be secured, where there is very little to hold or retain the +filling, better than gold, owing to the ease and greater certainty of +its adaptation to the retaining points or edges of the cavity. + +"It will be said, however, that tin fillings will wear away. The +surfaces that are exposed to mastication undoubtedly will wear in time; +but the filling does not become leaky if it has been properly packed and +condensed, nor will the margins of the cavity be attacked by further +decay on that account. + +"Altogether, I believe that we can make more perfect fillings with tin +than we can with gold, taking all classes of cavities; but it must not +be understood that it is proposed that tin should ever take the place of +gold where the circumstances and conditions indicate that the latter +should be used. Of course, the virtue is not in the gold or the tin, but +in the mechanical perfection of the operation, and tin having more +plasticity than gold, that perfection can be secured with more ease and +certainty. + +"If we compare tin with amalgam, we must certainly decide in favor of +the former and give it preference; as if it is packed and condensed as +perfectly as may be, we know just what such fillings will do every time. +We know that there will be no changes or leakage of the fillings at the +margins; whereas, with amalgam, the rule is shrinkage of the mass, and +consequently the admission of moisture around the filling, the result +being further decay. It is not contended that this is always the result +with amalgam, but it is the general rule; yet we must use amalgam, as +there are not a few cases where it is the best that we can do; but it is +to be hoped, and I think it may be said, that as manipulative skill +advances, amalgam will be less and less used. For so-called temporary +work, very often I prefer tin to gutta-percha, as it makes a much more +reliable edge and lasts longer, even when placed and packed without +great care."--_N. Y. Odon. Society Proceedings_, page 51, 1894. + +One of the main reasons which induced the writer to begin the use of tin +foil (_Stannum Foliatum_) for filling teeth, in 1867, was the fact that +amalgam filling failures were being presented daily. Believing that tin +could do no worse, but probably would do better, we banished amalgam +from the office for the succeeding seven years, using in the place of +it tin, oxychlorid, and gutta-percha. Since that time we have seen no +good reason for abandoning the use of tin, as time has proved it worthy +of great confidence. There is no better dental litmus to distinguish the +conservative from the progressive dentist. + +If we take a retrospective view and consider what tin foil was thirty +years ago, we do not wonder that so many operators failed to make tight, +good-wearing fillings. As it came from the manufacturer it looked fairly +bright, but after being exposed to the air for a short time it assumed a +light brassy color, and lost what small amount of integrity it +originally possessed. This tin was not properly refined before beating, +or something was put on the foil while beating, so that it did not have +the clean, bright surface and cohesive quality which our best foil now +has. No. 4 was commonly used, but it would cut and crumble in the most +provoking manner. Fillings were made by using mats, cylinders, tapes, +and ropes, with hand-pressure, on the plan for manipulating non-cohesive +gold foil, but it was difficult to insert a respectable approximal +filling. + +From the best information obtainable, the writer believes that Marcus +Bull (the predecessor of Abbey) was the first to manufacture and sell +tin foil in the United States, as he began the manufacture of gold foil +at Hartford in 1812. + +Several years ago a radical change came about in the preparation of tin +foil, for which the manufacturer should have his share of the credit, +even if the dentist did ask for something better, for the quality +depends largely upon the kind and condition of the tin used and on the +method of manufacture. + +For making tin foil for filling teeth, the purest Banca tin that can be +obtained is used. The tin is melted in a crucible under a cover of +powdered charcoal. It is then cast into a bar and rolled to the desired +thickness, so that if No. 6 foil is to be made, a piece one and one-half +(1-1/2) inches square would weigh nine grains. This ribbon is then cut +into lengths of about four feet, and spread on a smooth board slanted, +so that the end rests in a vat of clean water. + +Then apply to the exposed surface of the ribbon diluted muriatic acid, +and immediately wash with a strong solution of ammonia. Turn the ribbon +and treat the other side in the same way. It is then washed and rubbed +dry. The object of using the acid is to remove stains and whiten the +tin, and the ammonia is used to neutralize the effect of the acid. + +The strips are then cut into pieces one and a half inch square, filled +into a cutch and beaten to about three inches square. It is then removed +from the cutch and filled into a mold, and further beaten to the desired +size. When the ragged edges are trimmed off, the foil is ready for +booking. + +It takes skill and experience to beat tin foil, for it is not nearly as +malleable as gold; up to No. 20 it is usually beaten, but higher numbers +are prepared by rolling. In each case the process is similar to that +employed in preparing gold foil. The number on the book is supposed to +indicate the weight or thickness of the leaf. On the lower numbers the +paper of the book leaves its impression. + +On weighing sheets of tin foil from different manufacturers a remarkable +discrepancy was found between the number on the book and the number of +grains in a sheet, viz: Nos. 3, 4, 5, weighed 7 gr. each; No. 6, 9 gr.; +No. 8, from 9 to 18 gr.; No. 10, from 14 to 15 gr.; No. 20, 18 gr. In +some instances the sheets in the same book varied three grains. We +submit that it would be largely to the advantage of both manufacturer +and dentist to have the number and the grains correspond. No dentist +wishes to purchase No. 8 and find that he has No. 18; no one could sell +gold foil under like circumstances. Of the different makes tested, +White's came the nearest to being correct. The extra tough foil which +can now be obtained is chemically pure, and with it we can begin at the +base of any cavity, and with mallet or hand force produce a filling +which will be one compact mass, so that it can be cut and filed; yet in +finishing, it will not bear so severe treatment as cohesive gold. Always +handle tin foil with clean pliers, never with the fingers; and prepare +only what is needed for each case, keeping the remainder in the book +placed in the envelope in which it is sold, otherwise extraneous matter +collects upon it, and it will oxidize _slightly_ when exposed to the air +for a _great_ length of time. + +Before using tin foil, a few prefer to thoroughly crumple it in the +hands or napkin, under the impression that they thus make it more +pliable and easier to manipulate. + +A piece of blue litmus paper moistened and moved over a sheet of tin +foil will occasionally give an acid reaction, probably owing to the acid +with which it is cleaned before beating not having been thoroughly +removed. Foil held under the surface of distilled water and boiled for +five minutes, then left until the water is cold, removed and dried, +shows it has been annealed, which makes it work easily, but not as hard +a filling can be made from it as before boiling. + +In selecting and using this material for filling, we are able fully to +protect the cavity; and if we understand the material, and how to +manipulate it, we will surely succeed. This statement demands serious +attention, and appeals to every one who is anxious to practice for the +best interests of his patients; then let us make a thorough study of the +merits of the method and material. + +Until recently, the term cohesion had but one special meaning to +dentists, and that as applied to gold for filling teeth; being +understood as the property by which layers of this metal could be united +without force so as to be inseparable. The writer claims that good tin +foil in proper condition is cohesive when force is applied, and can be +used for filling teeth in the same manner in which cohesive gold foil is +used. This claim has been confirmed by several dentists, as noted in +another part of this volume. + +Cohesion is the power to resist separation, and it acts at insensible +distances. The integral particles of a body are held together by +cohesion, the constituent parts are united by affinity. + +The attraction between atoms of pure tin represents cohesion. Marble is +composed of lime and carbonic acid, which are united and held together +by affinity. + +The condition which obtains in the tin may be called cohesion, adhesion, +welding, or interdigitation, but the fact remains that layers of tin +foil can be driven together into a solid mass, making a tight filling +with less malleting than is required for gold; if it is overmalleted, +the receiving surface is injured. + +On account of its pliability it is easily adapted to the walls and +margins, and a perfect fit is made, thus preventing capillary action and +preventing further caries. Of all the metals used for filling it is the +best tooth-preserver and the most compatible with tooth-substance, and +the facility with which a saving filling can be made largely commends +it. + +Tin has great possibilities, and has already gained a high position as a +filling-material. Upon the knowledge we possess of the possibilities and +limitations of tin as a filling-material, and our ability to apply that +knowledge, will largely depend our success in preserving teeth. + +It is a good material for filling many cavities in the temporary teeth, +and children will bear having it used, because it can be placed quickly, +and but little force is required to condense one or two layers of No. 10 +foil. The dentin in young teeth has a large proportion of organic +material, for which reason, if caries takes place, many believe it is +hastened by thermal changes. Gold fillings in such teeth might prevent +complete calcification, on account of the gold being so good a +conductor; but if tin is used, there is much more probability of +calcification taking place, because of its low conductivity and its +therapeutic influence. It does not change its shape after being packed +into a cavity. Under tin, teeth are calcified and saved by the deposit +of lime-salts from the contents of the dentinal tubuli. This is termed +progressive calcification. + +Like other organs of the human body, the teeth are more or less subject +to constitutional change. The condition in which we find tooth-structure +which needs repairing or restoring should be a sure indicator to us in +choosing a filling-material. Up to the age of fourteen, and sometimes +later, we find many teeth which are quite chalky. In some mouths also, +at this period, the fluids are in such a condition that oxychlorid and +oxyphosphate do not last long; for some reason amalgam soon fails, while +gutta-percha is quickly worn out on an occlusal surface. In all such +cases we recommend tin, even in the anterior teeth, for as the patient +advances in years the tooth-structure usually becomes more dense, so +that, if desirable, the fillings can be removed, and good saving +operations can be made with gold. By treating cases in this manner very +little, if any, tooth-structure is lost. + +The teeth of the inhabitants of Mexico and Guatemala are characteristic +of their nervous and nervo-lymphatic temperaments; children ten years of +age often have twenty-eight permanent teeth, and they are generally soft +or chalky, but our dentists there report good success in saving them +with tin. + +In filling this class of teeth, we should be very careful not to use +force enough to injure the cavity-margin, for if this occurs, a leaky +filling will probably be the result. Still, we have seen some cases +where _slight_ imperfections at the margin, which occurred at the time +of the filling or afterward, did no harm, because the deposit of tin +oxid filled up the ends of the tubuli, thus preventing caries. We +believe that this bar to the progress of caries is set up more +frequently when tin is used than with any other metal under like +conditions. + + + + +CHAPTER V. + + +In some mouths tin does not discolor, but retains a clean, unpolished +tin color, yet when there is a sesquioxid of the metal formed, fillings +present a grayish appearance. In the same mouth some fillings will be +discolored, while others are not. As a general rule, proximal fillings +are most liable to show discoloration. Perhaps one reason is that on +occlusal and buccal surfaces they are subject to more friction from +mastication, movements of the cheeks, and the use of the brush. + +We have seen a large number of fillings which were not blackened, yet +were saving the teeth perfectly, thus proving to a certainty that +blackening of tin in the tooth-cavity is not absolutely essential in +order to obtain its salvatory effects as a filling-material. + +Where there is considerable decomposition of food which produces +sulfuretted hydrogen, the sulfid of tin may be formed on and around the +fillings; it is of a yellowish or brownish color, and as an antiseptic +is in such cases desirable. To offset the discoloration, we find that +the sulfid is insoluble, and fills the ends of the tubuli, thus lending +its aid in preventing further caries. A sulfid is a combination of +sulfur with a metal or other body. A tin solution acted on by +sulfuretted hydrogen (H_{2}S) produces a dark-brown precipitate (SnS), +stannous salt, which is soluble in ammonium sulfid (NH_{4})_{2}S_{2}; +this being precipitated, gives (SnS_{2}) stannic salt, which is yellow. +Brown precipitates are formed by both hydrogen sulfid and ammonium +sulfid, in stannous solutions. Yellow precipitates are formed by +hydrogen sulfid and ammonium sulfid in stannic solutions. The yellow +shade is very seldom seen on tin fillings; the dark brown is more +common. + +An oxid is a combination of oxygen with a metal or base destitute of an +acid. In oxidation the oxygen that enters into combination is not +sufficient to form an acid. The protoxid of tin (SnO) is black, and can +be obtained from chlorid of tin, or by _long_ exposure of tin to the +atmosphere. The oxygen in the saliva helps to blacken the tin, and the +metallic oxid penetrates the dentin more or less, acting as a +protection, because it is insoluble. Oxygen is the only element which +forms compounds with all others, and is the type of electro-negative +bodies; it combines with all metals, therefore with tin, and in many +cases only the metal is discolored, and not the tooth. Steam boilers are +made tight by oxidation. + +Where there is complete oxidation, the tooth is blackened to but a very +slight depth, and the oxid fills the ends of the tubuli, thus affording +an additional barrier to the entrance of caries. The filling itself will +prevent caries, but oxidation acts as an assistant. + +"In the mouth, a suboxid is more likely to be formed than a protoxid, +but both are black; sulfur and oxygen are capable of acting on tin under +favorable circumstances, such as warmth, moisture, full contact, +condensation of elements, and their nascent conditions; the first three +are always present in the mouth. The protosulfuret of tin is black." +(Dr. George Watt.) Others give the color as bluish-gray, nearly black. + +Experiments show that slight galvanic currents exist between fillings of +dissimilar metals in the mouth, and practical experience demonstrates +that these currents occasionally produce serious results. + +Direct galvanic currents do not decompose normal teeth by true +electrolysis, but acids resulting from decomposition of food and fluids +react upon the lime constituents of the teeth and promote secondary +caries. + +When two metals are so situated in the mouth that the mucous membrane +forms a connecting conductor and the fluids are capable of acting on +one metal, galvanic action is established sufficient to decompose any of +the binary compounds contained in these fluids; the liberated nitrogen +and hydrogen form ammonia, which being exposed to the action of oxygen +is decomposed and nitric oxid formed, resulting in nitric acid. We also +have in the mouth air, moisture, and decomposing nitrogenous food to +assist in the production of nitric acid. + +"Galvanic action is more likely to develop hydrochloric acid, for the +chlorids of sodium and potassium are present in the normal saliva and +mucus, and when decomposed their chlorin unites with the hydrogen +derived from the water of the saliva." (Dr. George Watt.) + +The fact should also be noted that both nitric and hydrochloric acids +are administered as medicine, and often assist in producing decay. + +When there is a battery formed in a mouth containing tin fillings and +gold fillings, and the fluids of the mouth are the exciting media, tin +will be the positive element and gold the negative element; thus when +they form the voltaic pair, the tin becomes coated or oxidized and the +current practically ceases. + +There is more or less therapeutical and chemical action in cavities +filled with tin, and its compatibility and prophylactic behavior as a +filling-material depends partly upon the chemical action which occurs. + +Some dentists fill sensitive cavities with tin, in order to secure +gentle galvanic action, which they believe to be therapeutic, +solidifying the tooth-structure. + +"Tin possesses antiseptic properties which do not pertain to gold for +arresting decay in frail teeth; it not only arrests caries mechanically, +but in chalky (imperfect) structure acts as an antacid element in +arresting the galvanic current set up between the tooth-structure and +filling-material." (Dr. S. B. Palmer.) If the metal is acted on, the +tooth is comparatively safe; if the reverse, it is more or less +destroyed. The galvanic taste can be produced by placing a piece of +silver on the tongue and a steel pen or piece of zinc under it; then +bring the edges of the two pieces together for a short time, rinse the +saliva around in the mouth, and the peculiar flavor will be detected. + +"In 1820 attention was called to the injurious effects of the galvanic +current on the teeth, and dentists were advised never to use tin and +amalgam in the same mouth. + +"A constant galvanic action is kept up in the mouth when more than one +kind of metal is used in filling teeth, and galvanism is often the +cause of extensive injury to the teeth. The most remarkable case I ever +saw was that of a lady for whom I filled several teeth with tin. After a +time decay took place around some of the fillings. I removed them and +began to refill, but there was so much pain I could not proceed. I found +that by holding a steel plugger an inch from the tooth I could give her +a violent galvanic shock. I observed that the exhalation of the breath +increased the evolution of galvanism." (Dr. L. Mackall, _American +Journal of Dental Science_, 1839.) + +"When a faulty tooth in the upper jaw had been stopped from its side +with tin, the interstice between it and the adjoining tooth being quite +inconsiderable, while the upper surface of a tooth not immediately +beneath it in the lower jaw was stopped with the same metal, I have +known a galvanic shock regularly communicated from one tooth to the +other when by the movement of jaws or cheeks they were brought near +together." (Dr. E. Parmly, _American Journal of Dental Science_, 1839.) + +"An interesting debate here sprung up on the action where two metals are +used in one filling, such as gold and tin, the saliva acting as a +medium, and where the baser metal is oxidized by exhalents and by +imbibition through the bony tooth-structure." (Pennsylvania Society of +Dental Surgeons, 1848.) + +"A patient came to me and complained of pain in the teeth. Upon +examination I found an amalgam filling next to one of tin. With a file I +made a V-shaped separation, when they experienced immediate relief from +pain." (Dr. Nevill, _American Journal of Dental Science_, 1867.) + +In regard to the decay of teeth being dependent on galvanic action +present in the mouth, Dr. Chase, in 1880, claimed that a tooth filled +with gold would necessarily become carious again at the margin of the +cavity, wherever the acid secretions constantly bathe the filling and +tooth-substance. A tooth filled with amalgam succumbs to this +electro-chemical process less rapidly, while one filled with tin still +longer escapes destruction. The comparative rapidity with which teeth +filled with gold, amalgam, or tin, are destroyed is expressed by the +numbers 100, 67, 50. He prepared pieces of ivory of equal shape and +size, bored a hole in each, and filled them. After they had been exposed +to the action of an acid for one week, they had decreased in +weight,--viz, piece filled with gold, 0.06; amalgam, 0.04; tin, 0.03. + +"With tin and gold, some have the superstition that the electricity +attendant upon such a filling will in some way be injurious to the +tooth; it matters not which is on the outside, when rolled and used as +non-cohesive cylinders each appears. We say that neither experimentally, +theoretically, nor practically can any good or bad result be expected +from the electrical action of a tin-gold filling on tooth-bone, and +neither will the pulp be disturbed." (Dr. W. D. Miller, _Independent +Practitioner_, August, 1884.) + +"When the bottom of a cavity is filled with tin which is tightly +(completely) covered with gold, there is _practically_ no galvanic +action and there is no current generated by contact of tin and +gold,--_i.e._, no current leaves the filling to affect the dentin. That +portion of tin which forms the base is more positive than a full tin +filling would be. The effect is to cause the surface exposed to dentin +to oxidize more than tin would do alone; in that there is a benefit. In +very porous dentin there is enough moisture to oxidize the tin, by +reason of the current set up by the gold." (Dr. S. B. Palmer.) + +Electricity generated by heat is called thermo-electricity. If a cavity +with continuous walls is half filled with tin and completed with gold, +or half filled with silver and completed with gold, and the junctions of +the metal are at 20-1/2 deg. C. and 19-1/2 deg. C., if the electrical action +between the tin and gold be 1.1, the action between the silver and gold +will be 1.8, thus showing the action in silver and gold to be nearly +two-thirds more than in the tin and gold, a deduction which favors the +tin and gold. + +Rubbing two different substances together is a common method of +producing an electric charge. Is there not more electricity generated +during mastication on metal fillings than when the jaws are at rest? +Friction brings into close contact numerous particles of two bodies, and +perhaps the electrical action going on more or less all the time through +gold fillings (especially when other metals are in the mouth) accounts +for a powdered condition of the dentin which is sometimes found under +cohesive gold fillings, but not under tin. + + + + +CHAPTER VI. + + +White caries, the most formidable variety known, may be produced by +nitric acid, and in these cases all the components of the tooth are +acted upon and disintegrated as far as the action extends. In proximal +cavities attacked by this kind of caries, separate freely on the lingual +side, and fill with tin. When such fillings have been removed the dentin +has been found somewhat discolored and greatly solidified as compared to +its former condition; this solidification or calcification is more +frequent under tin than gold, which is partly due to the tin as a poor +conductor of heat. Nature will not restore the lost part, but will do +the next best thing--solidify the dentin. In some cases, under tin, the +pulp gradually recedes, and the pulp-cavity is obliterated by secondary +dentin. In other cases the pulps had partly calcified under tin. It has +been known for years that tin would be tolerated in large cavities very +near the pulp without causing any trouble, and one reason for this is +its low conducting power. Attention is called to the fact that gold is +nearly four times as good a conductor of heat as tin, and more than six +times as good a conductor of electricity. Where tin fillings are +subject to a large amount of attrition, they wear away sooner or later, +but this is not such a great detriment, for they can easily be repaired +or replaced, and owing to the concave form produced by wear the patient +is liable to know when a large amount has been worn away. That portion +against the wall of the cavity is the last removed by wear, so that +further caries is prevented so long as there is any reasonable amount of +tin left. If at this time the tooth has become sufficiently solidified, +proper anchorage can be cut in the tin or tooth, one or both, as +judgment dictates, and the filling completed with gold. A tin filling, +confined by four rather frail walls, may condense upon itself, but it is +so soft and adaptable that the force which condenses it continually +secures the readaptation at the margin; thus there will be no leakage or +caries for years. Owing to its softness and pliability, it may be driven +into or onto the tubuli to completely close them from outside moisture, +and with a hand burnisher the tin can be made to take such a hold on +dry, rough tubuli that a cutting instrument is necessary to remove all +traces of it. + +Tin foil has been found in the market that under a magnifying glass +showed innumerable tiny black specks, which, upon being touched with an +instrument, crumbled away, leaving a hole through the foil. More than +likely, some of the failures can be attributed to the use of such foil. +Good tough foil, well condensed by hand or mallet force, stays against +the walls of a cavity and makes a tight filling, and ought to be called +as near perfect as any filling, because it preserves the tooth, and +gives a surface which will wear from five to twenty years, depending +upon the size and location of the cavity and tooth-structure. Buccal +cavities in the first permanent molars, and lingual cavities in the +superior incisors, filled for children from six to eight years of age, +are still in good condition after a period of twenty years. Perhaps the +limit is reached in the following cases, all in the mouths of +_dentists_: One filling forty years old; one forty-two; four on the +occlusal surface, fifty; in the latter case gold had been used in other +cavities and had failed several times. Lingual cavities in molars and +bicuspids can be perfectly preserved with tin. Tapes of No. 10 foil, +from one to three thicknesses, can be welded together and will cohere as +well or better than semi-cohesive gold foil, and it can be manipulated +more rapidly; therefore, if desirable, any degree of contour can be +produced, but the contour will not have the hardness or strength of +gold, so in many cases it would not be practicable to make extensive +contours with tin, owing to its physical characteristics. + +No. 10 will answer for all cases, and it is not as liable to be torn or +cut by the plugger as a lower number, but one need not be restricted to +it, as good fillings can be made with Nos. 4, 6, or 8. More teeth can be +saved with tin than with any other metal or metals, and the average +dentist will do better with tin than with gold. It is invaluable when +the patient is limited for time or means, and also for filling the first +permanent molars, where we so often find poor calcification of +tooth-structure. In cases of orthodontia, where caries has attacked a +large number of teeth, it is well to fill with tin, and await further +developments as to irregularity and caries. + +If cavities are of a good general retaining form, that will be +sufficient to hold the filling in place; but if not, then cut slight +opposing angles, grooves, or pits. Cavities are generally prepared the +same as for gold, except where there is a great deal of force brought +upon the filling; then the grooves or pits may be a little larger; +still, many cavities can be well filled with less excavating than +required for gold, and proximal cavities in bicuspids and molars, where +there is sufficient space, can be filled without removing the occlusal +surface, and here especially should the cavities be cut square into the +teeth, so as not to leave a feather edge of tin when the filling is +finished, as that would invite further caries and prove an obstruction +to cleansing the filling with floss. + +In proximal cavities involving the occlusal surface, cut the cervical +portion down to a strong square base, with a slight pit, undercut, or +angle, at the buccal and lingual corners; where there is sufficient +material, a slight groove across the base, far enough from the margin so +that it will not be broken out, can be made in place of the pit, +undercut, or angle; then cut a groove in the buccal and lingual side +(one or both, according to the amount of material there is to work +upon), extending from the base to the occlusal surface; in most of these +cases the occlusal grooves or pits would have to be excavated on account +of caries; thus there would be additional opportunity for anchorage. In +place of the grooves the cavity may be of the dovetail form. In nearly +all proximal cavities in bicuspids and molars, some form of metal +shield, or matrix, is of great advantage, as they prevent the tin from +crushing or sliding out. By driving the tin firmly against the metal, a +well-condensed surface is secured; and as the metal yields a little, we +can with a bevel or thin plugger force the tin slightly between the +metal and the margin of the cavity, thus making sure of a tight filling, +with plenty of material to finish well. After removing the metal, +condense with thin burnishers and complete the finish the same as for +gold. Where no shield or matrix is used, or where it is used and removed +before completing the filling, it is often desirable to trim the +cervical border, for in either case there is more light and room to work +when only a portion of the cavity has been filled. Tin cuts so much +easier than gold, it is more readily trimmed down level with all +cervical margins. + +Be sure that all margins are made perfect as the work progresses, and if +the cavity is deep and a wide shield shuts out the light, then use a +narrow one, which can be moved toward the occlusal surface from time to +time. + +In filling the anterior teeth when the labial wall is gone, and the +lingual wall intact or nearly so, use a piece of thin metal +three-quarters of an inch long and wide enough to cover the cavity in +the tooth to be filled, insert it between the teeth, and bend the +lingual end over the cavity; the labial end is bent out of the way over +the labial surface of the adjoining tooth, as shown in Fig. 4. When the +labial wall is intact or nearly so, access to the cavity should be +obtained from the lingual side, and in this case the bending of the +shield would be reversed, as shown in Fig. 5. The shield is not +absolutely essential, but it helps support the tin, and also keeps a +separation. + +[Illustration: FIG. 4.] + +[Illustration: FIG. 5.] + +It is preferable to save the labial wall and line it with (say) five +layers of No. 4 semi-cohesive gold folded into a mat and extended to the +outer edge of the cavity; this gives the tooth a lighter shade, and +bicuspids or molars can be filled in the same manner. Cases are on +record where incisors with translucent labial walls, filled by this +method, have lasted from twenty-three to thirty-seven years. + + + + +CHAPTER VII. + + +For the last ten years the writer has been using tin at the cervical +margin of proximal cavities in bicuspids and molars, especially in deep +cavities (now an accepted practice), and he finds that it prevents +further caries oftener than any other metal or combination of metals he +has ever seen used. In filling such cavities, adjust the rubber, and use +a shield or matrix of such form as to just pass beyond the cervical +margin; this will generally push the rubber out of the cavity, but if it +does not, then form a wedge of wood and force between the metal and the +adjoining tooth, thus bringing the metal against the cervical margin, +and if a small film of rubber should still remain in the cavity, it may +be forced out by using any flat burnisher which will reach it, or it can +be dissolved out with a little chloroform. Fill from one-fourth to +one-half of the cavity with tin, and complete the remainder with gold +when the tooth is of good structure; this gives all the advantages of +gold for an occlusal surface. + +Before beginning with the gold, have the tin solid and square across the +cavity, and the rest of the cavity a good retaining form, the same as +for gold filling; then begin with a strip of gold slightly annealed and +mallet it into the tin, but do not place too great reliance upon the +connection of the metals to keep the filling in place. + +On the same plan, proximal cavities in the anterior teeth can be filled, +and also buccal cavities in molars, especially where they extend to the +occlusal surface. The cervical margin should be well covered with tin +thoroughly condensed, thus securing perfect adaptation, and a solid base +for the gold with which the filling is to be completed. Time has fully +demonstrated that the cervical margin is most liable to caries, and here +the conservative and preservative qualities of tin make it specially +applicable. + +"Electrolysis demonstrates to us that no single metal can be decomposed, +but when gold and tin are used in the above manner they are united at +the line of contact by electrolysis. The surface of both metals is +exposed to the fluids of the mouth, and the oxid of tin is deposited on +the tin, by reason of the current set up by the gold; thus some atoms of +tin are dissolved and firmly attached to the gold, but the tin does not +penetrate the gold to any great extent." (Dr. S. B. Palmer.) + +This connection of the metals assists in holding the filling in place, +but it is more likely to break apart than if it was all gold. After +electrolysis has taken place at the junction, it requires a cutting +instrument to completely separate the tin and gold. + +For filling by hand pressure, use instruments with square ends and +sides, medium serrations, and of any form or size which will best reach +the cavity. + +For filling with the hand mallet, use instruments with medium +serrations, and a steady medium blow with a four-ounce mallet; in force +of blow we are guided by thickness of tin, size of plugger, and depth of +serrations, strength of cavity-walls and margins, the same as in using +gold. The majority of medium serrated hand mallet pluggers will work +well on No. 10 tin of one, two, or three thicknesses. If the tin shows +any tendency to slide, use a more deeply serrated plugger. The +electro-magnetic, and mechanical (engine) mallet do not seem to work tin +as well as the hand mallet or hand force, as the tendency of such +numerous and rapid blows is to chop up the tin and prevent the making of +a solid mass, and also injure the receiving surface of the filling. In +using any kind of force, _always_ aim to carry the material to place +before delivering the pressure, or blow. + +In order to obtain the best results, there must be absolute dryness, and +care must be exercised, not thinking that because it is _tin_ it will be +all right. Skill is required to make good tin fillings, as well as when +making good gold fillings. Always use tapes narrower than the orifice of +the cavity; they are preferable to rolls or ropes. After a few trials it +is thought that every one will have the same opinion. A roll or rope +necessarily contains a large number of spaces, wrinkles, or +irregularities, which must be obliterated by using force in order to +produce a solid filling; thus more force is employed, and more time +occupied in condensing a rope, than a flat tape; the individual blow in +one case may not be heavier than in the other, but the rope has to be +struck more blows. The idea that a rope could be fed into a cavity with +a plugger faster and easier than a tape has long ago been disproved. +Many of the old-fashioned non-cohesive gold foil operators used flat +tapes, as did also Dr. Varney, one of the kings of modern cohesive gold +operators. + +The tape is made by folding any portion of a sheet of foil upon itself +until a certain width and thickness is obtained. This tape is very +desirable in small or proximal cavities where a roll or rope would catch +on the margin and partially conceal the view. + +In the form of a tape, perhaps more foil can be put in a cavity, and +there may be more uniform density than when ropes are used. Tapes can +also be made by folding part of a sheet of foil over a thin, narrow +strip of metal. Fold the tin into tapes of different lengths, widths, +and thicknesses, according to the size of the cavity; then fold the end +of the tape once or twice upon itself, place it at the base of any +proximal cavity, and begin to condense with a foot plugger of suitable +size, and if there is a pit, groove, or undercut which it does not +reach, then use an additional plugger of some other form to carry the +tin to place; fold the tape back and forth across the cavity, proceeding +as for cohesive gold. In small proximal cavities a very narrow tape of +No. 10, one thickness, can be used successfully. For cavities in the +occlusal surface, use a tape as just described, generally beginning at +the bottom or distal side, but the filling can be started at any +convenient place, and with more ease than when using cohesive gold. In +any case if the tin has a tendency to move when starting a filling, +"Ambler's left-hand assistant" is used, by slipping the ring over the +second finger of the left hand, letting the point rest on the tin. This +instrument is especially valuable in starting cohesive gold (see Fig. +6). This is the easiest, quickest, and best manner of making a good +filling, relying upon the welding or cohesive properties of the tin. + +Many operators have not tried to unite the tin and make a solid mass; +they seem to think that it cannot be accomplished, but with proper +pluggers and manipulation it can be done successfully. + +[Illustration: FIG. 6.] + +For large occlusal or proximal cavities, the tapes may be folded into +mats, or rolled into cylinders, and used on the plan of wedging or +interdigitation, and good fillings can be produced by this method, but +the advantage of cohesion is not obtained, and more force is required +for condensing. They are, therefore, not so desirable as tapes, +especially for frail teeth. When using mats or cylinders, the general +form of the cavity must be depended upon to hold the filling in place. +To make the most pliable cylinders, cut a strip of any desired width +from a sheet of foil and roll it on a triangular broach, cutting it off +at proper times, to make the cylinders of different sizes. + +A cylinder roller, designed by the author, is much superior to a broach. +(See Fig. 7.) When the cavity is full, go over the tin with a mallet or +hand burnisher, being careful not to injure the cavity-margin. Cut down +occlusal fillings with burs or carborundum wheels, and proximal fillings +with sharp instruments, emery strips or disks. After partially +finishing, give the filling another condensing with the burnisher, then +a final trimming and moderate burnishing; by this method a hard, smooth +surface is obtained. + +Fillings on occlusal surfaces can be faced with No. 20 or 30 tin, and +burnished or condensed, by using a burnisher in the engine, but do not +rely upon the burnisher to make a good filling out of a poor one. + +[Illustration: FIG. 7.] + +By trimming fillings before they get wet, any defects can be remedied by +cutting them out; then with a thin tape (one or two layers of No. 10) +and serrated plugger proceed with hand or mallet force to repair the +same as with cohesive gold. + +Another method of preparing tin for fillings is to make a flat, round +sand mold; then melt chemically pure tin in a clean ladle and pour it +into the mold; put this form on a lathe, and with a sharp chisel turn +off thick or thin shavings, which will be found very tough and cohesive +when freshly cut, but they do not retain their cohesive properties for +any great length of time,--perhaps ten or twenty days, if kept in a +tightly corked bottle. After more or less exposure to the air they +become oxidized and do not work well, but when they are very thin they +are soft, pliable, and cohesive as gold, and any size or form of filling +can be made with them. + +Among the uses of tin in the teeth, the writer notes the following from +Dr. Herbst, of Germany: "After amputating the coronal portion of the +pulp, burnish a mat of tin foil into the pulp-cavity, thus creating an +absolutely air-tight covering to the root-canal containing the remainder +of the pulp; this is the best material for the purpose." There has been +a great deal said about this method, pro and con, notably the latter. +The writer has had no practical experience with it, and it need not be +understood that he indorses it. + +If a pulp ever does die under tin, perhaps it will not decompose as +rapidly as it otherwise would, owing to its being charged with +tin-salts. + +The Herbst method of filling consists in introducing and condensing tin +in cavities by means of smooth, highly tempered steel engine or hand +burnishers. In the engine set of instruments there is one oval end +inverted cone-shaped, one pear-shaped, and one bud-shaped. The revolving +burnisher is held firmly against the tin, a few seconds in a place, and +moved around, especially along the margins, not running the engine too +fast. Complicated cavities are converted into simple ones by using a +matrix, and proximal cavities in bicuspids and molars are entered from +the occlusal surface. The tin foil is cut into strips, and then made +into ropes, which are cut into pieces of different lengths; the first +piece must be large enough so that when it is condensed it will lie +firmly in the cavity without being held; thus a piece at a time is added +until the cavity is full. The hand set of burnishers has four which are +pear-shaped and vary in size, and one which is rather small and +roof-shaped. In filling and condensing they are rotated in the hand +one-half or three-quarters of a turn. + +Dr. Herbst claims a better adaptation to the walls of the cavity than by +any other method. Proximal cavities in bicuspids and molars can easily +be filled; the tin can be perfectly adapted against thin walls of enamel +without fracturing them; less annoyance to the patient and less work for +the dentist; can be done in half the time required for other methods. + +Fees should be reasonably large, certainly more than for amalgam, for +we can save many teeth for a longer time than they could have been +preserved with cohesive gold. Many are not able to pay for gold, but +they want their teeth filled and _saved_, and it is expected that we +will do it properly and with the right kind of material; thus it is our +duty in such cases to use more tin and less amalgam. + +We should always take into consideration the amount of good accomplished +for the patient,--the salvation of the tooth,--and if we are sure, from +experience and observation, that the tin filling will last as long as a +gold one in the same cavity, or longer, then the fee should be as much +as for gold, with the cost of the gold deducted. The amount of the fee +ought to be based upon the degree of intelligence, learning, and skill +required; upon the amount of nervous energy expended; upon the draft +made on the dentist's vitality; upon what benefit has been given the +patient; upon the perfection of the result; and, everything else being +equal, upon the time occupied; the value of this last factor being +estimated in proportion to the shortness of it. + + + + +CHAPTER VIII. + + +Dr. Robinson's Fibrous and Textile Metallic Filling is a shredded +metallic alloy, mostly tin, and has the appearance of woven or felt +foil. It is prepared in a machine invented by the doctor especially for +the purpose, and he gives directions for using as follows: "Cut the +material into strips running with the selvage, and fill as you would +with soft foil; use it in all surrounding walls, and finish with a +mallet burnisher. Where the surface comes to hard wear, weld on gold +with long, sharp serrated pluggers, and finish the same as with gold +fillings. The advantage over gold for cervical, buccal, and lingual +walls is the perfect ease with which it is adapted, and it can be +burnished so as to be absolutely impervious to moisture. Sharp, +coarse-serrated pluggers are particularly desirable when using hand +pressure." It comes in one-half-ounce boxes, filled with sheets less +than two inches square; the thin ones are used for filling, and the +thick ones make good linings for vulcanite. + +This material is easy to manipulate, but great care is required in +condensing at cavity-margins, so as to make a tight filling, and also +not injure the margins. It makes as hard a surface as tin foil, and can +be cut, polished, and burnished so that it is smooth and looks well; it +can be used in temporary or chalky teeth, as a small amount of force +condenses it. By using a matrix proximal cavities can be filled from +one-fourth to one-half full, and the rest filled with gold, relying on +the form of the cavity to hold the gold, regardless of its connection +with the fibrous material. If the surface is not overmalleted so as to +make it brittle or powdery, a strip of No. 4 cohesive gold, of four or +five thicknesses, may be driven into it with a hand mallet and plugger +of medium serrations; this union is largely mechanical, but of +sufficient tenacity to make manipulation easy, as the material makes a +solid foundation to build upon. After exposure to the oral fluids, +electrolysis takes place at the junction of the metals. + +In 1884 Dr. Brophy said, "I have used Robinson's material for two years, +and find it possesses good qualities, and can be used in deciduous +teeth, first permanent molars, and cervical margins with better results +than can be obtained with any other material by the majority of +operators." + +Malleted with deeply serrated pluggers, it will make a filling which +will not leak. It has saved many teeth from caries at the cervical +margin where it might have recurred sooner had cohesive gold been used. +In the mouth it changes color about the same as tin foil, and a few +fillings did not maintain their integrity, but became crumbly and +granular. + +For conducting properties it ranks about with tin, and fillings can be +made more rapidly than with cohesive gold. We have used ounces of it, +but time has proved that everything that can be done with it in filling +teeth can also be accomplished as well and in some cases better with tin +foil. + +In 1878 Dr. N. B. Slayton patented his Felt Foil, which was said to be +tin cut into hair-like fibers by a machine, then pressed into small +sheets and sold in one-half-ounce books, but it sold only to a very +limited extent. Soon after this Dr. Jere Robinson, Sr., invented a +machine and began the manufacture of a similar article, but he found he +was infringing on the Slayton patent, so he purchased the Slayton +machine and made satisfactory terms to continue his own manufacture of +fibrous material. After this little was heard of Slayton's Felt Foil, +but Robinson's was considerably used. The two materials look and are +manipulated almost exactly alike. Dr. Robinson has both of +above-mentioned machines now in his possession. + +Archibald McBride, of Pittsburg, Pa., in 1838, made a roll of a portion +of a sheet of tin, and then used just enough gold to cover it, aiming +to keep the gold on the surface, so as to have the filling look like one +of all gold, and not with the idea of deriving any special benefit from +the effects of wear or preservation as obtained by thus combining the +two metals. The fee for a gold filling was one dollar; tin, fifty cents. +Some operators have advocated using tin and gold (symbol Tg), rolled or +folded together in alternate layers, thus exposing both metals to the +fluids of the mouth; claiming that fillings can be made quicker, are not +so subject to thermal changes, and can be inserted nearer the pulp than +when gold is used. This may be true in comparison with gold, but these +three claims are entirely met by using tin alone. Others say that this +union of gold and tin will preserve the teeth as well as a correct gold +filling, making no conditions or restrictions as to tooth-structure or +location of cavity. They say that it preserves the cervical margin +better than gold; that it expands _slightly_. + +A description of some different methods of combining and manipulating +tin and gold is subjoined: + +(_a_) Two sheets of No. 4 cohesive gold and one of the same number of +tin are used; place the tin between the gold, cut off strips, and use +with hand or mallet force the same as cohesive gold; if non-cohesive +gold is used, the strips can be folded into mats or rolled into +cylinders, and are used on the wedging plan, the same as non-cohesive +gold, or the strips can be folded back and forth in the cavity until it +is full. + +(_b_) Lay a sheet of non-cohesive gold, No. 3, on a sheet of tin of the +same number, cut off strips, roll into ropes and use as non-cohesive +gold. It is easily packed and harder than tin, and has a preservative +action on the teeth. Line the cavity with chloro-balsam as an insulator +against possible currents and moisture; especially should this be done +in large cavities or chalky teeth. + +(_c_) A sheet of non-cohesive gold, No. 4, is laid on a sheet of tin of +the same number, cut into strips and rolled into cylinders, or folded +into blocks, always in equal portions; then they will unite to the +extent of two leaves. These fillings sometimes become a solid mass about +the color of amalgam, and last very well, as the metals have become +united by electrolysis. An excess of tin will be marked by lines or pits +in the filling, showing where the tin has been disintegrated or +dissolved by the chemical action which occurs on the surface exposed to +moisture. + +No doubt, good fillings have been made by the above methods, yet some +were granular, gritty, and were easily removed, while others were quite +smooth and hard; probably in the first instance the proportion of tin +and gold was not proper,--that is, not equal; or it was not well +condensed. Tin being the positive element, it is more easily acted on +and disintegrated by electrolysis (chemical action of the fluids). + +When this combination does become hard, it wears longer than tin on an +occlusal surface, but we believe that in some cases where it was used +the teeth could have been saved just as well with either tin or gold, or +by filling part of the cavity with tin and the rest with gold. + +If tin foil is laid on 22-carat gold and vulcanized, it becomes +thoroughly attached and will take a tin polish; the attraction or +interchange of atoms takes place to this extent. + +This combination of tin and gold can be used at the cervical margin, or +a cavity can be lined with it, and the remainder filled with cohesive or +non-cohesive gold. + +"Tin and gold (Tg) folded or rolled together in equal portions possesses +a greater number of desirable properties than any other material, for it +is easily adapted, has antiseptic action and a lower conductivity than +gold. A new filling is harder than tin, softer than gold, but after a +time it becomes as hard as amalgam. It oxidizes and thus helps make +tight margins, and is very useful at cervical margins; generally +discolors, but not always, and does not discolor the tooth unless a +carious portion has been left, and then only discolors that portion. In +oral fluids it is indestructible if well condensed, otherwise it is +crumbly. There is no change of form, except a _slight_ expansion, which +does no harm. A weak electric current is set up between the gold and +tin, and tin oxid is formed. The hardening and discoloration both depend +upon the separation of the tin by the electrical action and its +deposition on the surface of the gold. I generally prepare cavities the +same as for non-cohesive gold, but a Tg filling may be held in a more +shallow cavity and with less undercuts than for gold. Hand pressure is +adopted, but a mallet may be used advantageously. Lay a sheet of No. 4 +non-cohesive gold on a sheet of No. 4 tin, then cut into strips and +twist into ropes; keep the tin on the outside, for it does not tear as +easily as gold. Carry the material against the walls and not against the +base, otherwise the filling will be flat or concave; but should this +occur, then force a wedge-shaped plugger into the center of the filling, +and drive the material toward the walls, and then fill the hole or +remove all the filling and begin anew. + +"In very deep cavities use a mat of Tg, dampened in carbolic acid and +dipped in powdered thymol, as a base; this has an antiseptic action, and +also prevents pressure on or penetration into the pulp. + +"Drs. Abbot, Berlin; Jenkins, Dresden; Sachs, Breslau, have observed +tin-gold fillings from fifteen to twenty-five years, and say that for +certain cases it is better than any other material. I use square-pointed +pluggers (four-cornered), as part of the packing is done with the side +of the plugger. Tg is useful in partly erupted molars, buccal cavities +under the gums, occlusal cavities in temporary teeth, cavities where all +decay cannot be removed. Use Tg with a gold capping in small, deep +occlusal cavities, cavities with overhanging walls, occlusal cavities +with numerous fissures, large, deep occlusal cavities near the pulp, in +proximal cavities. + +"Line labial walls of incisors with non-cohesive gold, and fill the +remainder with Tg. For repairing gold fillings I use Tg." (Dr. Miller, +Berlin, _Dental Cosmos_, 1890.) + +Dr. Jenkins, of Dresden, says, "I use Tg in soft, imperfect teeth, of +which there are plenty in Germany, because it has pliability, +adaptability, slight susceptibility to thermal changes, makes a +water-tight joint, very useful at cervical margins, and can be used with +a minimum amount of pressure. When packed dry and with the gold next to +the tooth, discoloration occurs only on the surface; packed wet, the +whole discolors. I do not attribute its success to electrical action. +Lay a sheet of No. 4 tin on a sheet of No. 4 non-cohesive gold, fold so +as to keep the gold on the outside; use the strip with lateral pressure, +doubling it upon itself." + +Dr. A. H. Thompson: "After several years' successful use of tin-gold, I +commend it for approximal cavities, cervical margins, and frail walls. +The oxid formed penetrates the enamel and dentin; if a filling wears +down, cover the surface with gold." + +Dr. Pearson: "I do not like tin and gold in alternate layers. I prefer +No. 10 tin foil." + +Dr. James Truman: "I believe that tin-gold has a positive value as a +filling-material." + +"I prepare tin-gold by taking a sheet of No. 4 non- or semi-cohesive +gold, fold them together (or twist them) so as to have the gold on the +outside, and then fill any cavity with it. Since adopting the above +combination I have almost abandoned amalgam. This is recommended on +account of its density, ease of insertion, capacity for fine finish, +non-conducting and non-shrinking qualities, and compatibility with +tooth-substance. Those who have not used it will be surprised at the +rapidity with which it can be manipulated. It may be employed in any +cavity not exposed to view, also in crown, buccal, and approximal +fillings which extend into the occlusal surface, as it offers an +astonishing resistance to wear. It can be used anywhere that amalgam +can, and with more certainty of non-leakage, and it has the additional +advantage that it can be finished at the same sitting. Care is necessary +in manipulating it, so as to avoid chopping. I use hand pressure when +filling, and the mallet to condense the surface." (Dr. A. W. Harlan, +_Independent Practitioner_, 1884.) + +"Pure tin foil is employed in connection with non-cohesive gold in +filling proximal cavities in bicuspids and molars; a sheet of gold and a +sheet of tin are folded together." (C. J. Essig: "Prosthetic +Dentistry.") + +Dr. Benj. Lord says, "A combination in which I find great interest is in +the use of soft or non-cohesive gold with tin foil. This is no novelty +in practice, but I think that, for the most part, too great a proportion +of tin has been used, and hence has arisen the objection that the tin +dissolved in some mouths. I am satisfied that I myself until recently +employed more tin than was well. I now use from one-tenth to one-twelfth +as much tin as gold, and no disintegration or dissolving away of the +tin ever occurs. I fold the two metals together in the usual way of +folding gold to form strips, the tin being placed inside the gold. The +addition of the tin makes the gold tougher, so that it works more like +tin foil. The packing can be done with more ease and certainty; the +filling, with the same effort, will be harder, and the edges or margins +are stronger and more perfect. + +"The two metals should be thoroughly incorporated by manipulation. Then, +after a time, there will be more or less of an amalgamation. By using +about a sixteenth of tin, the color of the gold is so neutralized that +the filling is far less conspicuous than when it is all gold, and I very +often use such a proportion of tin in cavities on the labial surfaces of +the front teeth. + +"If too much tin is employed in such cases, there will be some +discoloration of the surface of the fillings; but in the proportion that +I have named no discoloration occurs, and the surface of the filling +will be an improvement on gold in color." + +"Dr. Howe. I would like to ask Dr. Lord whether, in referring to the +proportions of tin and gold, he means them to be considered by weight? + +"Dr. Lord. No, not by weight, but by the width of the strip of tin and +the width of the strip of gold. I get the proportions in that way, then +lay the tin on the gold and fold the gold over and over, which keeps the +tin inside the gold. + +"Dr. Howe. Will Dr. Lord tell us whether he refers to the same numbers +of gold foil and tin foil; as, for instance, No. 4 gold and No. 4 tin? + +"Dr. Lord. I use the No. 5 gold, and tin, I think, of about the +same number, but I always use No. 5 gold, both cohesive and +non-cohesive."--_New York Odontological Society Proceedings_, 1893, page +103. + +"Tin and gold, in the proportions generally used, do not present a +pleasing color; when finished, it looks but little better than tin, and +after a short time it grows dark, and sometimes black. I use five parts +of gold to one of tin, prepared as follows: Lay down one sheet of +Abbey's non-cohesive gold foil, No. 6; upon this place a sheet of No. 4; +upon this place a sheet of White's globe tin foil, No. 4; upon this +another sheet of Abbey's non-cohesive gold, No. 4; upon this a sheet of +No. 6. Cut into five strips and crimp; the crimped strips are cut into +pieces a little longer than the depth of the cavity to be filled; some +of the strips are rolled into cylinders, others are left open, because +easier to use in starting a filling. The color of this combination is +slightly less yellow than pure gold, and hardens just as rapidly as when +the proportions are one to one, but does not become quite as hard. This +preparation is non-cohesive, and should be inserted by the wedge +process. I use it in the grinding surface of molars and bicuspids, +buccal cavities in molars and bicuspids, cervical fissure pits in +superior incisors, proximal cavities in bicuspids and molars. If +proximal cavities are opened from the occlusal surface, the last portion +of the filling should be of cohesive gold to withstand mastication. In +simple cavities I place as many pieces as can be easily introduced, +using my pliers as the wedging instrument to make room for the last +pieces, and then condense the whole. If the cavity is too deep for this, +I use Fletcher's artificial dentin as a base, because it partly fills +the cavity and the ends of the cylinders stick to it. After an +approximal cavity is prepared, use a matrix held in place by wooden +wedges; the cylinders are about one-eighth of an inch long, and +condensed in two or three layers so as to secure perfect adaptation; +hand pressure is principally used, but a few firm strokes with a hand +mallet are useful. When ready to add the cohesive gold for the +grinding-surface, a few pieces of White's crystal mat gold should first +be used, because it adheres beautifully; thus a perfect union is +secured, but I never risk adding the gold without leaving a little +undercut for it in the tooth. By this method we obtain a beautiful +contour filling in a short time. Fillings should be burnished and then +polished with a fine strip, or moistened pumice on a linen tape. Where +cohesive gold is used for the entire filling, in many cases the +enamel-walls, already thin near the cervical margin, are made thinner by +the unavoidable friction of the polishing strips, but tin and gold is so +soft that a good surface is obtained in a few moments, and this danger +is reduced to a minimum. The surface is as smooth as a cohesive gold +filling, while such a surface is impossible with non-cohesive gold. In +cavities which extend so far beyond the margin of the gum that it is +impossible to adjust the rubber-dam, I prepare the cavity as usual, then +adjust a matrix, disinfect, dry, and fill one-third full with tin and +gold, then remove the matrix, apply the rubber, place matrix again in +position, and complete the filling by adding a little tin and gold, then +pure gold." (Dr. W. A. Spring, _Dental Review_, February, 1896.) + +Dr. T. D. Shumway says, "To have a scientific method of treatment, there +certainly must be a recognition of what is known of the nature of +tooth-structure. The method adopted more than a quarter of a century +ago, and which is at present employed, does not accord with the +teachings of the physiologist and microscopist; it is in direct +opposition to natural law. Each new discovery in the minute structure of +the teeth makes this more plain; pounding the teeth with a mallet cannot +be defended on scientific grounds. That it has not resulted more +disastrously is due to the wonderful recuperative energy of nature to +repair injury. No one would think of attempting to arrest and prevent +disintegration in any other vital organ by abrasion. Why, then, in +operation on the teeth, should we reverse the plain, simple teaching of +nature? Placing cohesive gold against the dentinal walls by pounding it +to heal a lesion is opposed to natural law. Cohesive gold will not be +mastered by force; if compelled to yield by superior strength, it seeks +a way to release itself; it is easily coaxed, but not easily driven. +Cohesive gold will unite with tin at an insensible distance just as +cohesive gold unites with itself; this union takes place without force +or pressure. Exactly what takes place when gold and tin are brought in +contact in the way described we do not know; we can only say that there +appears to be a perfect union. When cohesive gold was introduced to the +profession, while it was softer than non-cohesive foil, it was found to +resist under manipulation. This resistance is in accordance with the +well-known law that all crystalline bodies, when unobstructed, assume a +definite form. With gold the tendency is to a spherical form. The +process of crystallization is always from within outward. The mallet was +introduced to overcome the resistance caused by the development of the +cohesive property. Pounding gold with a mallet only increases its +crystallization. A crystalline body coming in contact with a fibrous one +can neither be antiseptic nor preservative; a filling-material which +possesses these properties must be one that corresponds or is in harmony +with tooth-substance. + +"In the interglobular spaces there is a substance which is called +amorphous or structureless, and a filling to be in harmony with this +substance should be amorphous or structureless in its composition. The +only materials we have which meet these conditions are gutta-percha and +tin. It is its structureless character that gives to tin its value. +Coming in contact with the living dentin, it is easily adapted, and does +not excite inflammation; it does not interfere with the process going on +within the teeth to heal the lesion caused by caries. A wound from a +bullet made of tin, unless it struck a vital part, nature would heal, +even if the cause of the wound was not removed, by encysting the ball. +This process of nature of repairing injury by encysting the cause is of +interest to the dentist in the study of suitable filling-materials. Tin +is very useful at the cervical margin of cavities; it acts as an +antiseptic or preservative, and reduces the liability to subsequent +decay. It is our endeavor to obtain a filling that will preserve the +teeth and reduce the liability to, if not wholly prevent, secondary +decay. The law of correspondence is of more consequence than the +mechanical construction of the filling. Tin can be used without that +rigid adherence to mechanical rule that is necessary to retain a filling +of cohesive gold; thus less of the tooth needs to be sacrificed. + +"Gold will unite with tin under certain conditions so as to form +apparently a solid mass. By a combination of these metals, not by +interlacing or incorporating one in the other, but by affinity, secured +by simple contact, we have all the preservative qualities of tin +combined with the indestructible properties of gold. For the base of the +filling we have a material in harmony with tooth-substance, introduced +in a way that is in accord with the law that governs all living bodies, +and for the outside a crystalline substance that corresponds to the +covering of the teeth. This covering of gold is a perfect shield to the +base, and the field for the display of artistic skill in restoring +contours is as broad as though gold was used entirely. Will a filling of +this kind withstand mastication? There is in the economy of nature a +provision made to overcome the resistance of occlusion. The teeth are +cushioned in the jaw and yield under pressure. The elasticity of the +substance of which the teeth are made is well understood. Ivory is the +most elastic substance known. The teeth coming together is like the +percussion of two billiard balls. Now a filling to save the teeth should +correspond as nearly as possible with the tooth-substance; it should not +be arbitrary, but elastic and yielding. Tin is interdigitous; it expands +laterally, and is almost as easily introduced as amalgam, and when put +in place does not have to be bound to be retained. Tin, with an outside +covering of gold to protect it, makes a filling to which amalgam bears +no comparison. In the light of scientific investigation there can be but +one method--a method based upon the recognized principle that the +_filling-material_ and the _manner_ of _introducing_ it shall correspond +to and be in harmony with the living, vital organism with which it comes +in contact. + +"After excavating, the cavity is treated with absolute alcohol, as +cleanliness and thorough dryness are absolutely essential. + +"The _tin_ is put in with steel pluggers, after the method of wedging; +it must be thoroughly condensed, so as to leave a smooth surface, and +enough used to come up to where the enamel and dentin join. + +"The effect is not produced by incorporating or interlacing the gold +with the tin; we rely upon the affinity of the two metals to retain the +gold; no undercuts, angles, or pits are made in the tin, dentin, or +enamel. The gold, extra cohesive from No. 4 to 40, is made to adhere to +the tin by simple contact, without pressure or force; the union is not +mechanical. + +"The instruments used for filling the remainder of the cavity with gold +are Shumway's ivory points, which adapt the gold nicely to the margin. + +"The set consists of five and were patented in 1881, and have been used +by me since that time for manipulating cohesive gold. One 'point' is for +proximal cavities in the anterior teeth; three 'points' of different +sizes are for occlusal cavities; one 'point' for proximal cavities in +bicuspids and molars and labial and buccal cavities; the sides, edges, +and ends of the 'points' are used, as the purpose is simply to obtain +contact. + +"The 'point' shown full size in Fig. 8 is of more general application +than any of the others, and is used for proximal cavities in bicuspids, +also labial and buccal cavities. The handle is made of ebony, and has a +silver ferrule, from which the ivory extends to the end and completes +the instrument. + +"The metal pin in the end of the handle is for picking up and carrying +the gold." + +[Illustration: FIG. 8.] + +Tin has been used successfully for completely lining cavities, filling +the remainder with gold; it is also useful for repairing gold fillings. + +Two or three thicknesses of tin foil may be pressed into a cavity with a +rubber point or hard piece of spunk, allowing it to come well out to the +margin; filling the rest with amalgam. + +"As a lining it presents to dentin an amalgam of tin and mercury which +does not discolor the dentin like ordinary amalgam, and helps do away +with local currents on the filling, which is one cause of amalgam +shrinkage in the mouth." (Dr. S. B. Palmer.) + +When caries extends to the bifurcation of roots, make a mat of two or +three layers of tin, place it in the bifurcation and use it as a base in +filling the rest of the cavity with amalgam. + +Tin is second in importance in alloys for amalgam, as it increases +plasticity, prevents discoloration, reduces conductivity and edge +strength, retards setting, favors spheroiding, therefore should not be +the controlling metal. + +It will be noticed that when cavities are lined with tin foil, it only +constitutes a small part of the filling, and that it has not been melted +with the other metals in the alloy before being amalgamated. + +A thick mat of tin has been recommended as a partial non-conductor under +amalgam fillings. + +Plastic tin can be made by pouring mercury into melted tin, or by mixing +the fillings with mercury at ordinary temperatures; it has a whitish +color, and if there is not too much mercury it occurs in the form of a +brittle granular mass of cubical crystals. Generally amalgams of tin and +mercury do not harden sufficiently, but forty-eight parts of mercury and +one hundred of tin make a fairly good filling, said to have a +therapeutical value; it should not be washed or squeezed before using, +and "is not a chemical combination." + +"Tin unites with mercury in atomic proportions, forming a weak +crystalline compound." (Dr. E. C. Kirk.) + +Mercury and tin readily unite as an amalgam under ordinary +circumstances, and form a definite chemical compound having the formula +Sn_{2}Hg. (Hodgen.) + +Another preparation of tin is known as stannous gold; it is manufactured +in heavy sheets and used the same as cohesive gold foil, and can be +easily manipulated, for it is rather plastic. + +Crystal tin for taking the place of tin foil: + +"Take chemically pure hydrochloric acid and dissolve tin foil in it +until a saturated solution is obtained; this may be done speedily by +heating the acid to a boiling point, or the same thing can be +accomplished in a few hours with the acid cold; it is then chlorid of +tin. It is then poured into a clean vessel and an equal quantity of +distilled water added; then a clean strip of zinc is plunged into the +solution, and tin crystals are deposited on the zinc; when there is +sufficient thickness on the zinc, remove both, and slip the crystals off +from the zinc into pure water, clean the zinc thoroughly, and reinsert +for another coating. The character of the crystallization will be +modified by the extent of the dilution of the solution in the first +place. Wash the tin in pure water until all traces of the acid are +removed, or a few drops of ammonia can be added to neutralize the acid. +It was suggested that it would be desirable to have some acid remain in +the tin for filling teeth in which there is no sensitive dentin. We have +put in a few fillings, and it works beautifully, and makes firmer +fillings than foil. It must be kept in water (probably alcohol is +better). It is pure tin, unites perfectly, and works easier than foil." +(Dr. Taft, _Dental Register of the West_, 1859.) + +For some years it was considered the best practice to enlarge all +root-canals and fill them with gold; in many of these cases the crown +cavities were filled with tin. + +Tin has been used for filling root-canals, but should there happen to be +any leakage through the foramen or tooth-structure, the tin will +discolor, and there may be infiltration into the crown, thus causing +discoloration, which might be objectionable if the crown was filled with +gold. Chloro-percha, gutta-percha, and oxychlorid of zinc are much +better for this purpose. + +The apical quarter of a canal has been filled with tin, and the +remainder with cement. Tin can be used for filling root-canals. Roll on +a broach small triangular pieces of the foil into very small cone-shaped +cylinders, carry to place, then withdraw the broach, and force in the +cylinder with the same or a larger broach; sometimes it is necessary to +use another broach, to push the cylinder off from the one on which it is +rolled. Another method is to carry and pack into the canal by means of a +broach, very narrow strips of No. 10 or 20 foil; or the apical third of +the canal could be filled with gold and the rest with tin. + +"About four years ago I concluded to try tin for filling root-canals; +then I began to look for patients whose general health was good, who had +strong, hardy-looking teeth, and kept their mouths in good condition. I +found one who answered all my requirements, with a molar to be filled, +and they would not have it filled with gold, or could not, on account of +the expense. I filled the canals with tin and the crown with amalgam. +After filling thirty-eight molars in this way I stopped for +developments. In six or seven weeks a lady returned with an inferior +molar abscessed, but at the time it was filled the circumstances were +such that it could not be properly treated. In nine months a gentleman +for whom I had filled four molars returned with an inferior one +abscessed. This is the sum-total of abscessed teeth where tin was used +in the root-canals, at the end of four years. The others are in good +condition, as I have seen them every six months. The roots were treated +from four to six weeks with carbolic acid before filling." (Dr. A. W. +Harlan, _Missouri Dental Journal_, 1872.) + +"Tin foil is just as good as gold for filling root-canals, as it is +entirely innocuous and sufficiently indestructible, while its softness +and pliability commend it. Where gold is to be used for the crown, it is +better to fill the bulbous portion of the pulp-cavity with gold also, so +as to weld these portions of gold together. The success of Dr. Harlan's +treatment was about equal to what might be expected from the same number +of teeth where the canals had been filled with gold." (Editor, _Missouri +Journal_.) + +Shavings turned from a disk of pure tin have been used in combination +with Watts's sponge gold for filling teeth, either by making a portion +of the filling from each metal or using them indiscriminately. + +A mat of tin foil dipped in chloro-percha can be used to cap an exposed +pulp, or a concave tin disk can be used for the same purpose. A mat of +tin has been used over a slight exposure of the pulp, because of its +slight conduction of heat and cold, thus avoiding much thermal +irritation and stimulating recuperation. + +Some use Robinson's fibrous material as a surface for tin fillings, +thinking that it is harder and will wear longer because of the erroneous +notion that it has platinum in it. + + + + +CHAPTER IX. + + +Tin has been recommended for temporary fillings in sensitive cavities, +because it is soft and easily packed in contact with the walls, has +therapeutic value, and after a time, when the temporary filling is +removed, the cavity is not as sensitive as formerly. + +It has been observed that starting gold in a sensitive cavity causes +pain, but starting tin in the same place seldom does. + +As long as tin preserves its integrity it preserves the tooth, therefore +tin fillings should not be repaired with amalgam, as their integrity may +be destroyed. Cavities can be partly filled with tin and completed with +sponge, fibrous, or crystalloid gold, after the manner described for +beginning with tin and finishing with gold foil. + +"I advocated tin at the cervical wall, cervico-lingual and +cervico-buccal angles to the thickness of 24 plate. Then complete the +filling with gold. Some of my most successful efforts in saving soft +teeth have been made in this way. This method has great value over gold +for the whole filling, but there are two objections to it: First, it +imparts to the cervical border the color and appearance of decay, so +that in three cases where an instrument passed readily into the tin I +have removed the fillings, without any necessity for it, not even +finding any softening of the margins. Second, its use requires the same +conditions of dryness, shape of cavity, delicate manipulation, +inconvenience to patient, and strain upon the operator as when gold is +used alone." (Dr. D. D. Smith, _Dental Cosmos_, 1883.) He admits that +this method saves _soft_ teeth and also cervical margins. Do not those +two very important factors more than counterbalance the color, and +oversight of the dentist? + +Dryness is an essential in making the best filling with any material, +and the time and strain consumed by the majority of operators in filling +with tin is not more than one-half what it is in using gold. + +"I use tin at the cervical margin of all proximal cavities in bicuspids +and molars. I prepare a matrix of orange-wood to suit each case, letting +it cover about one-third of the cavity, then fill with tin condensed by +hand force and automatic mallet; now split the matrix and carefully +remove it piece by piece, so as not to disturb the tin; then trim and +finish this part of the filling. Make another wooden matrix, which +covers the tin and remainder of the cavity, and fit it snugly to place. +Use a coarsely serrated plugger and begin packing non-cohesive gold +into the tin, letting it fill about one-third more of the cavity; then +complete the last third (surface) with cohesive gold. I have tested this +method for twenty years, and it has given me splendid results. I always +tell patients that there will appear sooner or later a slight +discoloration near the gum, which must not be mistaken for caries." (Dr. +A. P. Burkhart.) + +Another use for tin in the operating-room is found in Screven's +"Gutta-percha-coated Tin Foil," a cohesive, antiseptic non-conductor, of +which the inventor says: "Cement fillings that have been kept dry for +ten hours after mixing will be much harder than those soon exposed to +moisture, and they will retain that hardness though exposed to moisture +afterward. This preparation will keep a filling perfectly dry in the +mouth, and when removed the filling will be found hard as stone. There +is nothing better for lining cavities, holding nerve-caps in position, +holding a preparation in place when devitalizing a pulp where the tooth +is so much broken away as to make it difficult to prevent a filling +showing through the enamel, and for many other purposes." + +High-heat gutta-percha has been used as a base in deep occlusal, buccal, +and approximal cavities, completing the fillings with tin. Occlusal +cavities may be filled with tin; then after the filling is condensed and +finished, drill out the center and fill with cohesive gold, not cutting +away the tin so as to expose the margin; such fillings wear well, as +much of the attritial force comes on the gold portion of the filling. + +With the exception of the part in brackets, the following article is +from the _British Journal_, May, 1887: + +"If a person eats an oyster stew at 130 deg. F., a gold filling would carry +the difference between the temperature of the stew and that of the +mouth, 130 - 98 = 32 deg., almost undiminished to the bottom of the cavity; +allowing 2 deg. of diminution, then the cavity around the gold filling has +assumed 128 deg.; now the person feels warm and drinks ice-water at 32 deg.. +Taking into consideration the specific heat of the gold filling, it will +assume about 40 deg., which it carries with a diminution of the cold of +about 4 deg.,--that is, as if it was 44 deg.,--into the interior of the cavity; +then the cavity will assume 44 deg., the difference within one-tenth of a +minute being 128 - 44 = 84 deg., a change which would produce a violent +inflammation in any organ which was not accustomed to it. This +derangement in the tooth means interruption of circulation, and young +teeth will be most affected. + +"Thermal effect depends on heat-conducting power [gold is nearly four +times as good a conductor of heat as tin] and also on specific heat, so +the more the latter approaches that of the tooth the less it is liable +to produce sudden changes [thus favoring tin]. Specific heat manifests +itself by the speed of changes, while the heat-conducting power +influences the intensity [then the intensity of heat in a gold filling +would be three or four times as much as in a tin filling]. In speed gold +produces this change in one-tenth of a minute" [tin in one-fifth,--that +is, gold absorbs heat and expands about twice as fast as tin]. + +In 1838 Dr. J. D. White introduced sharp-wedge-shaped instruments for +filling teeth, and he claims to have been the first to use them; they +pack laterally as well as downward, and present as small a surface to +the filling as possible, so that the greatest effect may be produced +upon a given surface with a given power. Rolls of either tin or gold are +made by cutting any desirable portion from a sheet of No. 4 foil; cut +this portion once transversely, place on a napkin or piece of chamois, +then with a spatula fold a very narrow portion of the edge once upon +itself; then with the spatula resting on the thickened edge draw the +spatula away from it with gentle pressure, and the foil will follow in a +roll. + +[Illustration: FIG. 9.] + +The old method of using rolls, ropes, and tapes or strips is the same, +but we will describe one method of using tapes. (See Fig. 9.) A _strip_ +is a single thickness of foil in ribbon form; a strip folded lengthwise +once, twice, or more forms a _tape_ of two, four, or more thicknesses of +foil. The tin foil should be cut into strips and folded into tapes +proportioned in width and thickness to the size of the cavity. One end +of the tape is carried to the bottom of the cavity and then forced +against the side opposite the point where we intend to finish; now +remove the wedge-shaped plugger and catch the tape outside of the +cavity, and fold another portion against that already introduced, +letting all the folds extend from the bottom to a little beyond the +margin. Proceed in this manner, with care and sufficient force, until +the cavity is full, using for the last folds a small instrument. +Condense the surface with a large plugger, then go over it carefully +with a small instrument, and if any part yields, force in a wedge-shaped +plugger and fill the opening in above-described manner; condense, +burnish, and trim alternately until the surface is level with the +cavity-margin. By extending the folds from the orifice to the base of +the cavity, the liability of the tin to crumble or come out is +effectually prevented, and by putting it in with a wedge-shaped plugger +it is pressed out into all depressions of the walls. + +A later method of filling with tape or rope is to use wedge-shaped +pluggers with sharp serrations, filling the _ends_ of the cavity, and as +the two parts approach each other that next to the wall should be in +advance of the rest, thus an opening will be left in the center which +can be filled with a smaller tape or rope. + +Another old method: Take a piece of foil and roll it into a hard ball; +then gradually work it into the cavity, being careful to have +sufficient around the margin. + +Still another suggested method: Roll a piece of foil into a loose ball, +place it in the cavity, and pass a wedge-shaped plugger into its center. +This has the effect of spreading the tin toward the walls of the cavity, +the opening to be filled with folds in a way already described. The +wedge is used as often as it can be made to enter, filling each opening +with folds; then condense the surface, trim, and burnish. + +[Illustration: FIG. 10.] + +The English give the Americans the credit of first using cylinders. +Anyhow, Dr. Clark, of New Orleans, in 1855, used them made from +non-cohesive gold, and also from gold and tin in alternate layers. (See +Fig. 10.) + +Cylinders were used which were a little longer than the depth of the +cavity, introduced with wedge-shaped pluggers around the walls, each one +being closely adapted to the margin; then another row was added, which +was forced firmly against the preceding, continuing this process until +the cavity was full. The wedge, having a smooth end and sides, is forced +into the center so as to drive the tin toward the sides of the cavity, +being careful not to split the tooth; the opening is then filled with a +cylinder. Now force a smaller-sized wedge into the center of the last +cylinder, and into the opening introduce another cylinder, proceeding in +this manner until the filling is solid. Then condense the ends of the +cylinders, trim, and burnish. For the same operation more recent +pluggers are wedge-shaped, with sharp, deep serrations. In these cases +the filling is retained by the general form of the cavity and wedging +within a certain limit, and not by cohesion of the different parts. For +a time tin cylinders were prepared and put on sale at the dental depots. + +As far as we are aware, the first tin foil made use of in operative +technics was by Dr. F. S. Whitslar, who removed a disk of German silver +from an ivory knife-handle in 1845, then used hand pressure to fill the +cavity with tin. In the college course of operative technics tin foil +can be used, almost to the exclusion of gold foil, to demonstrate the +manipulation of both cohesive and non-cohesive gold. Shavings scraped +from a bar of tin are also useful in operative technics; they are more +cohesive than foil. + + + + + +End of the Project Gutenberg EBook of Tin Foil and Its Combinations for +Filling Teeth, by Henry L. 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