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124 THE TECHNICAL PROCEDURES IN FILLING TEETH.

sandpaper disk may often be used to advantage. When all
instrument marks have been removed with this it may be fol-
lowed by a leather disk and pumice, which at the last is carefully
run dry. This will give a brilliant surface. In using the
engine great care must be taken not to develop too much
heat, as this is likely to cause severe pain, and may do perma-
nent injury to the pulp of the tooth by setting up hyperaemia.
A hard steel burnisher should not be used on cohesive
gold fillings, for, if used with force enough to be of value,
there is danger of checking the enamel margins, and for the
reason that there is no necessity for its use if the surface of the
filling has been well condensed.
Finishing proximate fillings.—The teeth having been
separated to give room, and the filling built out sufficiently to
allow of its being finished to the original mesio-distal breadth
of the tooth, the gold will have been packed very solidly against
the proximating tooth. The first thing is to cut through
between this tooth and the filling with a Koeber saw, held in
the Wilson or Sibley frame. This cut should be close against
the proximating tooth, removing as little gold as possible.
Now, take a thread saw (made by grinding from the back of a
Koeber saw on an ordinary corundum wheel until its width is
reduced one-half), place it in the frame with the teeth toward
the back, and pass this between the filling and the proximating
tooth and work it under the gingival margin of the filling against
the neck of the filled tooth and sawing toward the occlusal, cut
away the overlap of gold. Afterward the saw may be turned
first one way and then the other, and cut away the overlap well
around to the buccal and to the lingual in case of very broad
fillings. Then the saws have done their full duty. In cutting
away the surplus with the saw especial care should be had not to
cut too much toward the occlusal, and thus cut away the contact
point. Now with the finishing knives begin at the gingival, and
cutting fine shavings (the krtives must be sharp), remove any
remaining overlap first and shave the proximate surface and the
gingival portion of the embrasures to the required form. When
the hand has become trained to the use of these knives, and they
are kept sharp, this part of the work is quickly done and well
done.
The buccal and lingual embrasures are then to be