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,