Page 92 - REMOVABLE ORTHODONTIC APPLIANCES
P. 92
84 Removable Orthodontic Appliances
lowers. As with a single instanding incisor, Retention
correction will not be stable unless there is a Clasps on 6|6 and 1|1 with a screw to move the
positive overbite at the end of treatment. labial segment forwards.
Anchorage
An appliance to procline the upper labial
The teeth that are clasped provide adequate
segment (Figure 9.8)
anchorage.
Active component
Double cantilever springs (or cranked finger Baseplate
springs, as described for single instanding Posterior bite planes are used to clear the
incisors) can be used. In this case, DID or 4J4 occlusion in the incisor region by about 1 mm.
might be clasped to resist the displacing Where a screw is used, the baseplate is split.
effect of the spring. When anterior retention
is a problem a screw can be used (Figure 9.9). Points to note
This has the advantage of being simple for Patients sometimes find a screw positioned at
the patient to manage and allowing retention the front of the mouth to be rather bulky. The
to be improved by clasping the central patient is instructed to turn the screw one quar-
incisors. ter-turn per week.
Figure 9.8 An appliance to procline the
upper labial segment. Adams' clasps 64|46
(0.7 mm), palatal cantilever springs
(0.6 mm) and molar capping.
Figure 9.9 An appliance to procline 21|12.
Adams' clasps 6|6 (0.7 mm), double Adams'
clasps on 1|1. (0.7 mm), molar capping and
a screw to procline 21|12.