Page 204 - My FlipBook

1 9 o METHODS OF FILLING TEETH.

is a section through a molar showing the buccal roots. The approx-
imal cavity and pulp-exposure are seen at a, and the new-drilled hole
at b. The next step is to insert a sharp fissure-bur in this hole at d,
when, using c as a fulcrum, and slowly tipping the instrument as it
cuts, a passage is made through the crown with comparative ease.
It must be observed here that we have two advantages by this method.
from below
First, by cutting upward, the enamel is approached from
the dentinal side, which is always easier than to attempt to cut enamel
from its outer surface. Second, by using the point c as a fulcrum
much less force need be exerted, and that, having a tendency to lift
the tooth from its socket, is less painful than the reverse would be.
Moreover, there is less danger of having the tool slip when cutting in
a hole, than when the effort is made to cut from the approximal
surface directly through the crown.
This groove being cut, the presentment from the coronal aspect is
as shown in Fig. 236.
FIG. 235. FIG. 236.
The next step is to
choose a rose
large
bur, and, passing it in
at the
posterior open-
ing a, bring it forward,
cutting away the den-
tine at both sides
thus the enamel, which
freely, undermining
a latter may then be removed with a chisel.
To those who have not essayed this method
a close study of the different steps is advised,
for by it otherwise difficult and extensive
removals of very dense tooth- structure are
made
moderately easy.
Where the cavity is at the anterior ap-
proximal surface, the pulp- chamber must be
entered with large rose burs, and then, using
the anterior adjacent tooth as the fulcrum,
the procedure is much the same as before,
the enamel being undermined from the den-
tinal side, and then cut away with chisels.
the same rules hold with the
Practically
lower molars. Here, as is often the case
a drill-hole is made as
where the pulp is exposed at the buccal cavity,
before in the anterior end of the sulcus until the chamber is entered,
after which the entire procedure is as though there were no buccal
cavity, except where the latter is so large that it is necessary to unite
it with the new crown cavity.