Page 365 - My FlipBook

MANAGEMENT OF CAVITIES BY CLASSES. 227
In the preparation of buccal and labial cavities for filling,
good management requires that all of the area of uncleanliness
be removed at once, including, of course, the last traces of soft-
ened enamel, no matter how sound and perfect the dentin may
be beneath. The occlusal line of the cavity margin should be
placed so far to the occlusal that it will be kept clean by masti-
cation of food, the gingival line should be placed so that it will be
well covered by the gum margin, and the mesial and distal lines
should be placed at the most favorable points near the mesial and
distal angles of the tooth. The object is the removal of the area of
liability to decay for the prevention of its recurrence. Wherever
the susceptibility to this class of decay is considerable, nothing
less will effect a cure. If in these cases the cavity in the dentin,
simply, is excavated and filled ever so well, decay will go on so
quickly to the mesial and to the distal of the filling that it will
be of no value. Formerly these were regarded as the most uncer-
tain of fillings, because of this speedy recurrence of the decay,
but since the principles of extension for prevention, as above
detailed, have been used in their treatment, these fillings have
become almost as certain of long endurance as fillings in occlusal
cavities. The main point in their successful treatment is the
careful study of the local conditions, the condition of suscepti-
bility being appreciated, and so cutting the cavity as to meet
these conditions. This becomes a matter of judgment in each
individual case, and upon this judgment success or failure
depends. It is always safer to cut wider than necessary than to
fall a little short.
The greatest difficulties are met with when these decays
occur in the teeth of young persons. In such cases the teeth are
more apt to be hypersensitive and the patient difficult to control,
and great patience, persistence and moral courage are required
of the operator to enable him to carry the cutting to the proper
limit. At the same time, the requirements for extension of the
cavities are much greater than in older persons. The suscepti-
bility to decay is greater. More time must elapse before there
is relief by the coming of immunity, and for these reasons more
is required of the filling. Also the free margin of the gum is
long in young persons and becomes shorter as age advances, and
if these cavities are not extended well to the gingival, the gingival
margin will become uncovered and exposed later, and come to
occupy the central area of liability to decay. Under such con-
ditions recurrence of decay along this margin is certain if the
susceptibility continues and safe cleanliness is not maintained