Page 52 - My FlipBook

METHODS OF FILLING TEETH.

tions, are most useful. One is Dr. W. W. Evans's form, Nos. 74 and
These are made either with or without a set screw. I believe
75.
that this screw has been practically useless to the majority of dentists,
"
and yet it is really invaluable. The inventor says of it, The office
of the screw is to tighten the hold in cases where the clamp does not
fit securely." While this may have been the object aimed at, it is a
not served for several reasons. In the first it not in-
purpose place,
frequently happens that the clamp is not pressed up sufficiently far to
allow the screw to reach the tooth at all. Secondly, when it does
touch the tooth it rests upon a sloping surface, so that if it is screwed
down it displaces the clamp. Again, were it to reach a perfectly flat
plane, at the very best part of the tooth for its action, a moment's
thought will show that to screw it down would have a tendency to lift
the jaws up from the tooth, and so loosen the clamp. Therefore as a
screw it is useless, but as a projection above the surface it is most
valuable. Supposing the tooth to be filled is a cuspid, the procedure

FIG. 55.

FIG. 54.

125
would be to
apply the dam over several teeth, and then tie ligatures
about the necks of the lateral incisor and the
bicuspid, leaving long-
ends. Next press the clamp high up on the tooth, and, holding it
firmly, make a knot with the loose ends of the ligatures from both
teeth, around the projecting head of the screw, so that when drawn
tightly it tends to force the clamp upward. Completing the knot
makes the clamp secure, and the operation may be finished without
fear of Of course, for this a small hook would
slipping. purpose,
answer in place of the screw-head, but we may utilize the clamp as it
is furnished to us. Therefore the form with the screw is preferable to
that which is without it.
The peculiar shape of this clamp makes it specially useful in cus-
the bulbous of the tooth at the side near the
pids, portion palatal
gum offering an excellent point of resistance to the concaved jaw,
while the two narrow above fit about the labial
projections admirably
surface and offer good view of the work. At the same time the clamp
is limited in its usefulness the fact that these
by projecting jaws fre-