Page 274 - My FlipBook

272 THE OPERATION OF FILLING CAVITIES.
teeth became the common practice in the hands of the skillful, and mod-
ern mi^thods of practice coupled with intelligent use of this form of
gold have made it possible for the operator of modern times to do that
which the earlier practitioner deemed impossible.
The beginner, however, must not lose sight of the fact that cohesive
foil cannot be worked after the same methods as non-cohesive foil. To
use cohesive foil in the form of mats or cylinders or in tightly rolled
ropes would mean inevitable failure in adaptation. The very property
which renders it valuable in the restoration of broken-down teeth and in
surfacing is the one which would condemn it if used carelessly in the^
interior of inaccessible cavities. Non-cohesive gold may be introduced
into a well-shaped cavity in large masses, and because of its softness
and ease of adaptation may be made to touch all points of the cavity
walls if persistent pressure be applied. On the contrary, cohesive foil
should be introduced in small pieces, the first of which should be Avell
anchored in a retaining pit or groove and each subsequent piece welded
thereto.
There are several modes of preparing the beaten cohesive gold foil
for the cavity, and good results are obtained by either of the following
methods.
A loosely rolled rope made of a quarter sheet of No. 4 or 5 foil
may be cut into lengths varying from one-eighth to one-quarter of

Fig. 225.

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Ribbons and strips.
an inch, and after annealing carried to the cavity upon the point of
the plugging instrument. Or a leaf may be folded with a spatula four