Page 757 - My FlipBook

SPREADING THE ARCH. Too

spring, as shown in Fig. 741. While resembling other devices for the
same purpose, it has this distinction : The bar connecting the bauds on
the lingual surfaces of the teeth is perforated at short intervals by
holes in which are fitted the ends of a Talbot spring or an Angle jack-
screw. This bar should be stiff, about No. 23 B. & S. gauge. The
position of the screw or spring may be changed, according to the part
which needs the greater expansion. If necessary, two springs dt two
Fig. 743.

Writer's combination with Angle's jack-screw.

jack-screw^s may be used at the same time. The coiled spring should
be bent to conform to the palatal vault, so as to interfere but little
with the patient's tongue as does the jack-screw.
In case of very short molars and bicuspids it is best to use Matte-
sou caps in place of bands, as shown in Fig. 742.
Fig. 744.

Writer's appliance for widening lower arch and moving incisors forward.
Fig. 743 shows tlie use of the jack-screw and Fig. 744 the appliance
for the lower arch. In this the Matteson spring is used with two coils