Page 11 - REMOVABLE ORTHODONTIC APPLIANCES

Introduction 3
Figure 1.2 Alignment of a
crowded lower labial segment can
occur spontaneously in a growing
patient following the relief of
crowding.

assist spontaneous alignment in the lower arch lower molars to move forwards from a class II
by virtue of the fact that biteplates can be used towards a class I relationship (Figure 1.3). This
to unlock the occlusion. change can sometimes be maximized by carry-
ing out lower extractions in advance of upper
extractions to establish a class I molar relation-
Mesial migration
ship early in treatment.
Natural mesial drift of the posterior teeth At the end of removable appliance treatment
occurs at any age but is more marked in the residual extraction space will often remain.
growing child. If extraction treatment is being This is a common target for criticism of the
considered this may represent an advantage or standard of removable appliance results but,
a disadvantage. It is a disadvantage when space provided that spaces are matching, not exces-
is barely adequate. It is an advantage whenever sive and that the cusnal relationships are
the extractions will create excessive space and correct, the spacing will usually improve subse-
particularly so in the lower arch, where mesial quently in a growing patient.
movement can not only assist in the closure of In the upper arch spontaneous mesial move-
first premolar spaces but may also allow the ment of buccal teeth can also assist space