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.)

"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.)

"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.)