US172812A - Improvement in dental foil - Google Patents

Description

UNITED STATES PATENT Orrrcn.

RICHARD S. WILLIAMS, OF NEW YORK, N. Y.

IMPROVEMENT- IN DENTAL FOIL.

Specification forming part of Letters Patent No. 172,8 [2, dated January 25, 1876; application filed November 16, 1875.

/ y OAsE B.

' provement in dental foil; and the invention consists in dental foil to which a small percentage of tin has been added, to take from it its cohesive properties after annealing, and,

therefore, be more easily manipulated by th dentist.

The well-known property inherent in pure gold of cohering after it is annealed renders it difficult for dentists, in some cases, to properly prepare it for use, since the cohering of the surfaces, when it is folded and rolled, renders the gold stiff, or, as it-is termed, hard. To prevent this,'and to enable the gold to fold or roll up soft, I take pure gold, add to it a small proportion of pure tin-say, onehalf a grain, or" less, of pure tin to nine hundred and ninety-nine and one-half grains of pure gold. These proportions may be slightly alt red; but the proportions lhave named will give excellent results.

The gold, being in this way alloyed, seems to have its tenacity increased; but the chief result obtained is that the surfaces of foil prepared from such alloyed gold, after it is annealed, will not adhere, but will, as it were, slide on each other, unless considerable pressure is used. Hence, foil made from gold in this way alloyed maybe readily folded or rolled, and yet the rolls or folds will be plia- Me and easily worked.

This result is produced by the heat used in annealing the foil, this heat slightly oxidizing the tin on the surface of the foil. This oxide is sutlicient tokeep the surfaces of the gold from coming in such close contact as to cohere, and, therefore, give all the advantages of annealed gold without the disadvantage of its adhering. But when it is desired that this gold shall adhere, as when filling a cavity, then the force with which it is pressed into the cavity will be sufficient to cause it to cohere, forming a solid mass, the same as the ordinary annealed gold.

The gold and thetin both being pure, when in use nothing deleterious can come from the use of the alloy, and hardly any perceptible change of color is noticeable in the gold from the addition of the tin.

It is obvious that the proportions of gold and tin above given may be varied to some extent without departing from the spirit of my invention, and I, therefore, do not wish {)0 limit myself to the proportions above given Having thus described my invention, what -I claim as new, and desire to secure by Letters Patent, is- Y As a new article of manufacture, dental foil alloyed with tin, substantially as described.

RIOHD. S." WILLIAMS.

Witnesses: H. L. WATTENBERG, G. M. PLYMPTON.