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144 THE TECHNICAL PROCEDURES IN FILLING TEETH.

of the incisal edge of the tooth ; rarely the labial wall should be
cut away. Then, to improve the approach still more, take a
small fissure bur in the engine, and approaching the canal from
the direction in which a broach would be introduced, pass it into
the canal, and cut by lateral pressure broadening the canal in a
direction to straighten the approach. This cutting will be
toward the disto-lingual if a distal cavity, or mesio-lingual if a
mesial cavity, if the approach is to the lingual of the incisal
edge. From whatever the direction of the approach, the cutting
is to be so directed that the broadening of the coronal portion
of the canal will straighten it. In this cutting special care
should be had that the end of the bur should not cut the oppo-
site side of the canal and roughen it, for if it should, the point
of an instrument will be catching in the rough points at every
effort to introduce it into the canal. By this cutting the curve
of the instruments introduced into the canal for the removal of
the pulp, or for filling the canal, will be much less abrupt, and
these operations can be done more perfectly.
It is particularly desirable that all cutting in opening the pulp
chamber be completed, and the cavity cleaned of chips or cut-
tings before the pulp is removed from the root canals. Often
these cuttings will fall into a small canal, and an instrument
thrust will so fasten them' as to occlude the canal. If in any
case it should become necessary to do more cutting after remov-
ing the pulp from one root canal in order to gain access to
another, a wisp of cotton to catch any chips should first be
placed in the open canal.

Removal of the Pulp.

The instruments used for removing the pulp from the
canals are the barbed broach and the smooth broach. Gen-
Usually the bulb
erally the barbed broach should be used first.
of the pulp will have been removed during the opening of the
pulp chamber, and the broach selected should be suited in size
to the canal. Test the broach before using it by taking the
point on the finger and bending it. See that it bends in a
regular curve. Occasionally in cutting the barbs the shaft is cut
too deeply at some point, which will cause it to break easily —
such a broach should be discarded. The broach should be held