n, 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
der