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744 ORTHODONTIA AS AN OPERATIVE PROCEDURE.

strength of the gold will permit, so that the point of contact with the
enamel will be as small as possible.
Lower Incisors Crowded in All Positions.—This is a very common
irregularity owing to the teeth being too large for the incisor space, or
the space being encroached upon by the canines.
The simplest way to make room is to extract one of the crowded
teeth. The four teeth are so nearly of the same size that few can tell
without counting whether there are three or four between the canines.
^Yllen room has been made, the remaining teeth may be brought into
line by the same means that have been described for upper incisors.
The labial bow attached to bands on bicuspids or canines will form
attachment for rubber bands or ligatures for moving the incisors into
position. In some cases it is better to spread the arch as shown in Fig.
733. Owing to the relative positions of the alveoli of the central incisor
and canine to that of the lateral incisor there is always a tendency for
the lateral incisor to erupt within the arch of the adjoining teeth.
In selecting the tooth for extraction in such cases it would seem most
natural to take the one most out of position labially or lingually ; but

that is not always best, because it often happens, as Dr. Case has
shown, that the contiguous teeth already lean toward each other, and
if drawn together after removal of such teeth will only lean toward
each other all the more noticeably with quite a V-shaped space at the
gum.
If possible, the tooth for extraction should be so selected that the
contiguous teeth lean from each other (Fig. 722), so that when drawn
together they will be forced into an upright position. If, however, a
wrong selection should have been made, the roots of the contiguous
teeth may be forced toward each other by the appliance shown in Fig.
821.1
Caution.—Before deciding on extraction in such cases the operator
should satisfy himself that the lower arch does not need expanding to
make room for the crowded incisors.
If by removing a tooth the lower arch is allowed to contract and the
^ Dr. Case, Dental Review, 1898, p. 584.