Page 75 - REMOVABLE ORTHODONTIC APPLIANCES

Class II malocclusions 67

Figure 8.5 Molar relationship more than half unit Figure 8.6 Molar relationship a full unit class II
class II with a crowded lower arch. Provided the molar with a crowded lower arch may be treated
lower arch can be expected to improve with removable appliances provided that the
spontaneously, the extraction of all four first underlying skeletal pattern is moderate. Extraoral
premolars and the use of upper removable support will be required.
appliances can treat this occlusion. Extraoral support
may well be needed in such cases.

overjet cannot be satisfactorily reduced by
of all four first premolars can be considered, tipping the incisors. Cases suitable for remov-
allowing for spontaneous alignment of the able appliance treatment are likely to have mild
lower arch and the use of appliances in the upper arch crowding and only a slightly
upper arch. Reinforcement of the anchorage by increased overjet.
the use of extraoral forces may be necessary in If there is mild lower arch crowding and the
such cases to hold the upper molars in place as patient is of an appropriate age then the extrac-
the buccal occlusion corrects (Figure 8.5). tion of all four first premolars might be consid-
ered with the wear of headgear to move the
upper molars distally into a class I relationship,
Molar relationship fully class II but only if the patient does not have a marked
skeletal II base (Figure 8.6).
Caution - many patients with an uncrowded The presence of severe lower arch crowding
lower arch and a full class II molar relationship with a class II molar relationship indicates an
also have a marked skeletal II dental base rela- extremely difficult case which will require
tionship. These should be avoided because the treatment by a specialist.