Page 841 - My FlipBook

THE CONTOURING APPARATUS. 839

place a napkin in the mouth, and dry the teeth and surrounding gum
with spunk. Pack it around the teeth, where it is hekl firmly in posi-
tion while the cement is being prepared and placed in the bands by an
assistant. See that all material used in polishing is removed from the
inner surface of the bands, and the surface scraped or scratched with a
sharp excavator.
The cement should be mixed thoroughly, but rapidly, to the con-
sistence of thick cream, and scraped from the spatula along the upper
and inner edges of the bands.
When each part of the appliance is ready, force it quickly and firmly
to its position ; its final adjustment being perfected by the use of the
mallet on a large oval plugger resting upon the soldered parts.
After the anchorage attachments have been cemented in place, make
an appointment for the next day to attach the remainder of the appa-
i-atus, in order to allow the cement to become perfectly hardened, that
the bands may not be dislodged, or even slightly started, by the strain
to which they are subjected in the final adjustment of the power bar.
Another way is to adjust the anchorage attachments to the ends of
the power bar—out of the mouth—after the parts have been perfected,
shaped, and fitted—and cement the whole to place in this condition.
By this method the whole apparatus can be attached to the teeth at one
sitting.
On account of the intense rigidity of the poAver bar it is important
that when it is in j)lace on the teeth tlie threaded ends should lie within
their respective anchorage tubes without exerting the slightest force in
any direction until it is applied, as intended, by the power of the screws
;
therefore great care should be observed in giving to it the proper shape,
by bending as accurately as possible upon the plaster model, and after-
ward by a trial fitting in the mouth before cementing the anchorage
bands.
With the ancliorage attachments and power bar in position the bands
are to be cemented to the anterior teeth. As eacli band is carried to its
place, it should be seen that the flattened surface of the upright bar is
pressed down firmly upon the power bar, so that an even force will be
given to each of the teeth when power is applied—it being presupposed
that in the trial fitting of the parts the power bar was shaped so as to
engage j)erfectl}' with the upright bars—the free euds of the latter ex-
tending slightly above it.
The same kind of apparatus may be employed upon the lower in-
cisors with perfect success, though there will not be the same tendency
to carry the entire alveolar ridge forward with the roots as on the
upper ; the change being largely by a metamorphosis of alveolar tissue.
An apparatus for contruding the roots of the anterior teeth is con-