Page 151 - My FlipBook

CORRECTION OF DENTAL IRRKCliLARITIES. •39
in mastication and i)e forced oiitwartl into line. Imj^'. 94
shows a form of this apphance.
Another device for forcing the cuspids ont into hne is
the (^r(Hnary jack-screws, of which there are several forms
on the market. Fig. 95 represents the Holmes appliance
in position. It is a comljination of the spring and screw
and is operated by the nut-fitting ends of the wrench; the
turning of the screw causes a forceful spring action to the
extent only of the screw thrust, and so avoids the common
danger of spring action, which, if neglected, may carry the
tooth too far.
Misplaced Bicuspids.—A simple method of moving a
bicuspid out into line is the small jack-screw of the Angle
system.
Fig. q6.

Another very ingenious method is the Jackson crib and
spring appliance. Fig. 96 shows such an appliance in posi-
tion. A base wire is shaped to the lingual side of the an-
terior teeth and anchored to the bicuspids by means of a
single "crib" appliance. To each of these latter is attached
a hook or eyelet to sustain a straight bar of spring wire that
is sprung over the anterior teeth.
Dr. Jackson gives another very simple fixture for the pur-