Page 146 - My FlipBook

142 FILLING TEETH.

FORMING CAVITIES.

The next step in the operation is the formation of
the cavity. By this the cavity is so formed that it
will retain the filling when properly introduced. In
very few cases is the cavity of proper form when the

decay is removed. Much time, patience, and labor
are required of the operator, for the proper accom-
plishment of this part of the work, and much endu-
rance on the part of the patient. Excavation is often
necessary to give a regular form to the cavity ; and
in this process there are several particulars worthy of
consideration. The great object, however, is to give
to the cavity such a form as will most certainly re-
tain the filling in place. The cutting for the forma-
tion of the cavity should be accomplished with the

least possible loss of healthy dentine ; this is a point
upon which good judgment should be exercised.
The strength of the walls of the cavity, and the
ability of the parts to withstand the pressure, both in
the introduction and consolidation of the filling and
in the act of mastication, should be well noted. It
may be regarded as a rule from wdiich there should
scarcely ever be a departure, that the enamel should
never be encroached upon in excavating to give form
to a cavity. When there is but a lining of dentine