Page 150 - My FlipBook

METHODS OF FILLING TEETH.
136
occur imperfections in the enamel which, being deep pits, readily serve
as an initial point for true caries. In this class of teeth we may find
such cavities as is shown in Fig. 149, where we see that the decay has
destroyed the edge to one side of the median line of the tooth. This
will happen oftener than the cavity shown in Fig. 150, where the ac-
tual or is absent. The of either of these cavities
tip point preparation
is simple, and is indicated by the dotted lines in the illustrations. It
consists of removal of all decay, which will usually leave a cup shape
favorable for our purpose anyway, but which may be strengthened by
slight extensions in opposite directions, rendering the filling, when
placed, larger within than at the orifice.
In Fig. 151 we see a cavity which would result were the last one
neglected. Its preparation and filling is similar to that of the smaller
cavity, except that we must get stronger anchorage, since a more ex-
tensive contour is now needed, and, moreover, having approached the

FIG. 149. FIG. 150. FIG. 151.

pulp, great care is requisite lest that organ be injured. The main
idea after the removal of all decay, is to avoid taking away any of the
dentine covering the end of the pulp, which we know is near. Indeed,
it is a general fact to be observed in the preparation of all cavities
by the methods which I advocate, that a well-marked hill of dentine
appears within the cavity and over the pulp, which principle has been
explained diagrammatically in Figs. 3, 4, 5, and 6. Avoiding, then,
the central point of the cuspid cavity, deep extensions are to be made
at each side, slanting away from the pulp and lying parallel to the
mesial and distal sides of the tooth. Where the cuspid is quite thick
an will be a con-
through, advantage gained by forming deep groove
necting these lateral extensions along the palatal part of the cavity.
A groove of some depth must be made in any event, for it must be
remembered that in mastication the forces exerted will operate to
throw the outward toward the labial side.
filling This undercut along
the palatal side therefore will be a valuable restraint, provided that it
is not made at the of the wall, a circumstance
expense weakening
which should prevent undercutting in any position. All of these cavi-
ties in cuspids 1 prefer to fill with gold. I like its appearance better