Page 204 - My FlipBook

200 CLASSIFICATION OF DECAYED CAVITIES.

These decayed fissures should be opened up by
cutting away any projecting portion of enamel, and
the cavities formed with a small chisel-shaped instru-
ment, beginning at the juncture of the fissure with
the main cavity, and cutting down to the bottom of
the decay in the manner of a mortise, thus cutting

out the entire fissure and the acute angle at its ter-
mination—the latter an important consideration. In
case there is a very considerable expansion of decay
at the termination of the fissure, the* bur drill may be
introduced into it, and the rest of the fissure cut out,
as the form of the cavity may indicate.
If blocks are used to fill these cavities, they should
be set in and compressed against the end of the fis-
sure, protruding from it sufficiently to admit of a
proper finish; and block after block added, till the
fissure is filled up to the main cavity. Where there
are two or three of these decayed fissures in one

tooth, it may be quite as much as can be done at
one sitting, to fill them, the main cavity being left
for another time. In such cases, the filling intro-
duced at the first sitting, should then be consolidated
and burnished, so that it may not absorb moisture till
the main cavity is filled, as already described. Much
care should be exercised to prevent the gold from
overlapping the enamel at the sides of these fissures.
In filling this modification with crystal gold or an-