Page 762 - My FlipBook
P. 762
—
(60 ORTHODONTIA AS AN OPERATIVE PROCEDURE.
In some cases tlie nrdi must he spread before attempting to reduce
the V shai)e, in which case the appliance shown in Fig. 741 may be used.
Fig. 752 shows the second stage in the treatment of a pointed arch.
The arch is first spread by means of a coil spring acting on a band
Writer's lingual bow and rubber bauds for rotation after spreading the arch.
on the first bicuspids, reinforced by bars resting on the canines and
second bicuspids. After sufficient room has been gained the lingual
bow may be inserted to retain the width of the arch. From this bow
a rubber band or a twisted ligature should be extended to a T-piece
between the central incisors or to a hook on a band on each central
incisor for the purpose of rotating.
Fig. 753.
Upper protrusion—cause (a) or (&).
Class 9. Upper Protrusion. Etiology.—Protrusion of the upper
anterior teeth may be due to several causes :
(rt) Abnormal (excessive) development of the upper maxilla—con-
stitutional.
(6) Teeth too large for the jaw—indirect heredity.
(c) Premature loss of the second deciduous molar, and forward move-
ment of the first permanent molar—acquired.
(60 ORTHODONTIA AS AN OPERATIVE PROCEDURE.
In some cases tlie nrdi must he spread before attempting to reduce
the V shai)e, in which case the appliance shown in Fig. 741 may be used.
Fig. 752 shows the second stage in the treatment of a pointed arch.
The arch is first spread by means of a coil spring acting on a band
Writer's lingual bow and rubber bauds for rotation after spreading the arch.
on the first bicuspids, reinforced by bars resting on the canines and
second bicuspids. After sufficient room has been gained the lingual
bow may be inserted to retain the width of the arch. From this bow
a rubber band or a twisted ligature should be extended to a T-piece
between the central incisors or to a hook on a band on each central
incisor for the purpose of rotating.
Fig. 753.
Upper protrusion—cause (a) or (&).
Class 9. Upper Protrusion. Etiology.—Protrusion of the upper
anterior teeth may be due to several causes :
(rt) Abnormal (excessive) development of the upper maxilla—con-
stitutional.
(6) Teeth too large for the jaw—indirect heredity.
(c) Premature loss of the second deciduous molar, and forward move-
ment of the first permanent molar—acquired.
