Page 66 - My FlipBook

so THE TREATMENT OF TEETH
fectly well adapted, but will stand the wear and tear
of mastication.
Just as this freedom and accuracy of manipulation
is interfered with in any case, and just as the shape
or depth of the cavity and the strength of the walls
departs from the ideal condition, so will the difficulty
of making well-adapted and solid non-cohesive fill-
ings be increased. Gold foil is prepared for non-
cohesive work much in the same way as for the
cohesive method. When pellets or cylinders are
used, they should be rolled more tightly, and a
thicker gold than that usually employed for cohesive
cylinders is advisable, No. 4 or No. 5 foil being
usually preferred. Cylinders are now generally used
for non-cohesive work, but those that are supplied by
the depots for this kind of work are often too stiff
to be easily used in approximal cavities. Useful
cylinders can be made as follows —Take a sheet of
:
No. 4 non-cohesive foil, fold it once on itself, cut
a strip the length of the sheet, one or two inches
broad, double over the end of the strip with straight,
fine-pointed, foil carriers or tweezers ; then with the
tweezers, supplemented with the fingers, gently roll
the gold strip. Keep the tweezers outside the roll, do
not wrap the gold round the points. By proceeding
in this way, always catching hold of the external
part of the roll, and cutting off the superfluous strip