Page 838 - My FlipBook

836 THE DEVELOPMENT OF ESTHETIC FACIAL CONTOURS.
When the bands have been fitted as described above, they should be
phiced upon the four incisors and a plaster impression taken of the
labial surfaces of the bands, teeth, and adjoining gum. For a tray to
carry the plaster to place use a thin piece of lead cut the proper
size.
After the impression is removed, carefully remove the bands and
place them in their respective positions on the impression ; the joints
of the bands will serve to guide them to place. This when filled with
Teague's or other investing material will give a model with the bands
in position, to which may be fitted and soldered the upright bars.
The upright bars are made of No. 14 wire, bent to fit the anterior
face of the band and tooth along the median line of its axis, and also
the gum to about ^ of an inch above its margin. In soldering them to
the bands, completely fill the V-shaped spaces on either side the upright
bars, to give sufficient rigidity and finish to the appliance. After they
have been soldered and removed from the model they are further finished
by filing the bars flat on the sides which lie next to the gum, tapering
them to one-half tlieir diameters at the upper ends. It is against this
surfiice that the power bar, P, is to rest, as shown in Fig. 893. The
upright bar may also be flattened somewhat over the face of the tooth,
but not at the point where it leaves the band for the gum, as full
strength and rigidity are required here. (In Fig. 893 the engraver has
made the upright bar appear far too light at this point—marked c—for
practical use in sustaining the great force of the power bar at b.)
The bars having been cut off even with the occluding ends of the
teeth, and properly rounded and polished, the small transverse grooves,
D, may be cut just above the ends to receive the fulcrum wire, F, No.
24 gauge, which is much smaller tlian shown in Fig. 893.
In constructing the anchorage portion of the apparatus to be attached
to the posterior teeth too much care cannot be observed in order that
the several parts perform the work assigned to them and the greater
portion of force be neutralized at points of anchorage.
When the second molars have fully erupted, band the first and
second molars—otherwise the second bicuspids and first molars—and
sometimes all three teeth. AVhere it becomes advisable to apply this
particular form of force before the eruption of the second bicuspids,
the second deciduous and first permanent molars will answer for the
purpose.
The banding material should be as wide as the tooth will permit,
and in thickness from Nos. 36 to 35 (or 0.005 to 0.0055 of an inch).
When the bands have been made as described and perfectly fitted, place
them in the positions they are to occupy and take a plaster impression
—one side at a time—allowing the plaster to barely cover the bands.