Page 836 - My FlipBook

834 THE DEVELOPMENT OF ESTHETIC FACIAL CONTOURS.
the direction iiulicated l)y the arrow, theii will the <)i)p().sing wall, i;, of
the alveolar socket near its margin receive nearly all of the direct force
;
and in j)roportion to its resistance will there be a tendency to move the
root in the o])j)osite direction. This will also hold good even if the
force be applied at a. Fig. 892, or as I'ar upon the root as may be per-
mitted by attaching a rigid npright bar, c, to the anterior surface of the

B-^

crown ; the only difference being that the direct force is distributed
over a greater area. But if, as in Fig. 893, to the lower end of c a
traction wire or bar, f, is attached and if the mechanical principles of
the machine be further enforced by uniting its posterior attachment to
the anchorage of the power bar, p, the anchorage force will be materially
neutralized and an independent static fulcrum at d created. The appa-
ratus now will distribute its force over the entire root, and give com-
plete direction and control of whatever power is put into it. The

Fig. 893.

entire tooth may be carried forward bodily or either end may be made
to move the more rapidly. The force thus directed to the ends of the
roots will have an increased tendency to move the more or less yielding
bone in which they are imbedded.
For practical illustrations of what has been accomplished by an
apparatus of this kind see cases described in sections I., IV., and V. of
this chapter.
The contouring apparatus is made entirely of German silver, with
the exception of the nuts, which are of nickel. German silver is pre-
ferred, not because it is cheaper than gold and platinum, but because it