Page 148 - My FlipBook

136 MECHANICAL DENTISTRY AND METALLURGY.
is soldered a piece of tuljing to accommodate the traction
bar or screw. A l^and is also fitted to the cuspid ; to this a
short tube is soldered on the palatodistal portion, into which
the bent end of the traction screw bar is engaged. The
nut, which is operated against the distal end of the tube,
will readily move the tooth into position.
We sometimes meet with obstinate cuspid teeth, which
refuse to drop into line after the necessary room has been
Fig. 91.

secured for them. When this is the case, an appliance,
such as is illustrated in Fig. 92,—the pull-back jack-screw
devised by Dr. F. H. Lee,—answers the purpose admirably.
The post or nut shown in the side cut is set in position
and held by vulcanizing into a rubber plate as shown in
the illustration ; the screw-bolt is then placed through the
post and a wire is passed around the tooth, the ends being
secured to the holes in the cross-head or swivel-block. The
w^ire is then taken up and tightened as the tooth is brought
into place. To prevent the plate from being moved out of