Page 730 - My FlipBook

728 ORTHODONTIA AS AN OPERATIVE PROCEDURE.

onaiiiel of the second decitliions molar. Force was exerted upon the
tooth to be nioNxnl by occasionally pinching this wire with the regu-
lating pliers (Fig. 676), two or three pinches being enough to lengthen
the wire sufficiently to move the tooth as far as should hv done at one
sitting.
"The simplest retainer is a band with a short piece of round wire
soldered to it, so that it will impinge upon the adjacent tooth. It is
necessary sometimes to fasten such a lug on each side of the band."
(See Fig. 677.)
When double rotation has been accomplished, the teeth may be
retained by soldering the bands together at the points of contact.
Angle's appliance for double rotation is easily understood from an
examination of Figs. 678 and 679. The piano-wire spring should not
be larger than No. 24 B. & S. gauge.
Fig. GTS. Fig. 679.

Angle's appliance for double rotation.
Although this appliance is very effective, two difficulties attend its
use. Sometimes the spring fails to slide through the tubes as the teeth

Fig. 680. Fig. 681.

Guilforcr.s lever for rotating. Angle's detaclialile lever for rotating.
rotate and the teeth are spread slightly apart. This tendency can be
obviated by tying a silk ligature from one tube to the other.
Sometimes the distal surfaces of the teeth will turn forward, so that
they will stand wholly out of the line of the other teeth. This can be
prevented by soldering lugs on the lingual surfaces of the bands, to rest
on the laterals. In some cases, as the centrals turn, these lugs will
slide on the inclined plane formed by the lingual surfaces of the laterals