Page 88 - REMOVABLE ORTHODONTIC APPLIANCES

80 Removable Orthodontic Appliances
Figure 9.3 A single lateral incisor in lingual
occlusion in an established dentition is often
associated with a shift of the upper centre-line.
Removable appliances alone cannot achieve
correction of such a crossbite.

Figure 9.4 Upper
lateral incisors, which
are crowded palatally,
may be associated with
a forward displacement
of the mandible on
closure, (a) Examination
of the patient with the
lateral incisors in the
initial contact position
(b) may demonstrate a
potentially increased
overjet (c) in a case that
initially appeared to be
mild class III.

contact (Figure 9.4). It is important to check for a spring to the palatal surface. Any forward
this before treatment is started. Such a situation movement is likely to reduce the overbite
may disguise an underlying mild class II occlu- further and produce a very foreshortened
sion and correction may produce an increased appearance because of the forward inclination
overjet on the other incisors. Allowance may of the, crowns. (A removable appliance may,
need to be made for this when planning treat- however, still constitute a useful initial treat-
ment. ment phase.)
Patients with a skeletal III base, who In the established dentition a mildly crowded
present with upper lateral incisors in crossbite lower arch, with incisor imbrication which will
and with their apices palatally placed, will not improve spontaneously following extrac-
present particular difficulties. Teeth with this tions, renders treatment more difficult and
type of inclination are difficult to engage with usually necessitates the use of fixed appliances.