Page 842 - My FlipBook

840 THE DEVELOPMENT OF ESTHETIC FACIAL CONTOURS.

structed in a vcrv similar manner. The direction of the two forces
being reversed, it becomes necessary, however, to make certain import-
ant variations. The power bar (i', Fig. 896) now exerting a traction
force, No. IG will he fonnd sufficiently large for all purjjoses. It is
not flattened, bnt rests in grooves cnt in the anterior surfaces of the
Fig. 896.

upright bars, B. The power-bar tubes should be soldered closely to the
anchorage bands so that the nuts which now work at the posterior ends
of the bar will not irritate the mucous membrane of the cheek. The
fulcrum bar, f, exerting in this apparatus a jack-screw force, should be

No. 16. It is flattened along its middle portion to engage with the
occluding ends of the upright bars at d, provision being made for the
purpose in the construction.
The power of the two forces being so great upon the upright bars,
with a tendency to lift the occluding ends from their attachments, and
thus allow the free ends to press into the gum, it is important with this
apparatus that the occluding end attachments be reinforced by soldering