Licence: Public Domain Mark
Credit: Tin foil and its combinations for filling teeth. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![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 con- ductor 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 mani- fests 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 min- ute [tin in one-fifti^,—that is, gold absorbs heat and expands about twice as fast as tin]. In 1838 Dr. J. D. AMiite 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 eft'ect may be produced upon a given sur- face 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](https://iiif.wellcomecollection.org/image/b2123100x_0109.jp2/full/800%2C/0/default.jpg)
