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156 THE TECHNICAL, PROCEDURES IN FILLING TEETH.
The approach to distal cavities in the upper second molars
is often somewhat from the buccal, and to facilitate this approach
in building the filling, the buccal wall should be strongly inclined
to the buccal, whenever this can be done without very positive
detriment to the case. One should never neglect to obtain such
form as will render the filling of the cavity convenient.
In the lower molars, especially those that have a strong
lingual inclination, the form of the distal cavity may be made
for filling with reverse pluggers. In this case the buccal wall
may be cut parallel with the long axis of the tooth and the gold
packed against it entirely with the reverse plugger.
The bicuspids are much smaller teeth than the molars and
deep cutting in the preparation of cavities weakens them rapidly.
There is, therefore, even a greater object in treating decays in
them very early when this is possible. In their treatment, the
same boxlike form of cavity must be used as in the treatment
of cavities in the molars. This is modified to suit the form of
the tooth, while all of its main features are retained. The same
instruments are used, or the smaller sizes of the same patterns.
The same care is necessary in extensions for prevention, both to
the buccal and to the Ungual, and many of them must be cut very
wide. In this, however, a greater number have very deep, wide-
open embrasures which limit the extension of decay so much
that rather narrow cavities may be made.
Figures 182-186 represent an ordinary case in an upper
second bicuspid with what may be termed a beginning decay
in which the whitening on the surface of the enamel was thought
to have extended to the possible buccal and lingual limits under
the conditions of the contact and near approach of area of its
surface to the first molar. A little burrowing in the dentin has
occurred. The occlusal surface is shown in Figure 183 to be
apparently perfect, though the grooves are rather deep. In
opening the cavity, smaller sizes of the same instruments as
were used in the preparation of similar cavities in molars should
be selected. Otherwise the opening of the cavity and the whole
process of its formation is the same. Figure 184 represents the
form of the cavity as seen from the distal, showing the buccal
and lingual enamel walls inclined outward, and Figure 185 as
seen from the occlusal. This shows the step formed for reten-
tion and strength for the resistance of the stress of hard usage
and with all of the deep grooves of the occlusal surface cut away.
Figure 186 illustrates the finished filling with its contact point
a little more rounded and prominent than the original tooth