Page 744 - My FlipBook

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742 ORTHODONTIA AS AN OPERATIVE PROCEDURE.

or a short piece of wire may be soldered to the front of tlie bow and
inserted between the centrals above the points and their mesial snr-
faces. Other short wires may be soldered on so as to engage the distal
borders of the laterals to prevent their being moved sideways. (See
Fig. 715, B.)
Fig. 717.
Fig. 717 shows the writer's modi-
fication of the Coffin spring plate for
moving incisors forward. A wire
should be imbedded in the anterior
portion of the plate to project between
the centrals to prevent sliding on the
inclined surfaces.
Retention of Teeth Moved
Forward.—This has often been ac-
complished by a simple vulcanite
plate retained by atmospheric pressure
and impinging on the lingual surfaces
Writer's modification of Colfiu split vul-
of all the teeth involved. Objections
canite plate.
to this are that it is easily displaced,
even sometimes by the incisors on whose inclined surfaces it impinges
retention of fermenting debris or secretions in contact with the teeth,
and liability to be left out by the carelessness of the patient, when the
teeth return partly to their malpositions. Fig. 718 shows a retaining

Fig. 718.

e.H.A
Angle's retainer.
appliance of Prof, Angle's, consisting of a Avire bent so as to rest in
contact with the lingual surfaces of the teeth involved, soldered to
bands on the canines, and the ends cemented in pits drilled in the
molars. It may be used in the lower arch as well as the upper. In
many cases the anterior portion only of this appliance may be used.