Page 165 - My FlipBook

COKRI'XTION OF DENTAL IRK KCl 'LARITIES. 153

willi a piece ot trial-plate wax. from wliicli, after being
\-ariiislie(l, a mold in sand is obtained and a die and counter-
die made. Between tliese a piece of soft and heavy brass
plate is struck up and drilled full of holes. After fashion-
iui^' heavy piano wires to cross the plate and extend suffi-
cientlv bevond to form hooks, they are soft soldered to the
brass plate and the latter covered with black silk with a
thick layer of cotton batting laid between the two. The
enlarged size of the chin piece will admit of this. The
piece thus padded will tit the chin and be soft enough to
prevent pain when pressure is brought to bear upon it.
—
Torsion. " The term torsion, as applied to the teeth,
signiiies that condition in which a tooth is found to be

Fig. 113.
Fig. 114.

turned upon its axis. Rotation refers to the act of twist-
ing or turning a tooth so as to bring it into normal position.
Torsion, therefore, describes the condition, and rotation the
operation."*
Rotation by Rubber Ring.—In the accompanying illus-
tration. Fig. 113, Dr. Guilford's method of employing bands
and rubber rings for rotation is given. Platinum bands
were fitted to the centrals, with a gold hook soldered to
each at points that would furnish the greatest amount of
tractile power. After the bands were cemented in place a
rubber ring was stretched from tooth to tooth, in the man-
ner shown in Fig. 113. The malposed tooth was thus
readily broug"ht into contact with its fellow, and at the same
* Guilford's " Orthodontia."