Page 84 - REMOVABLE ORTHODONTIC APPLIANCES

76 Removable Orthodontic Appliances
Figure 8.16 An appliance to use with
molar bands. The headgear is applied
directly to the tubes on the bands. The
unsupported springs (0.6 nnm) should
only be activated by 1-2 mm.

Points to note and alignment of the lateral incisors can be
The removable appliance is worn full time and carried out. A 'U' loop labial bow may be appro-
enhances the effect of the headgear, which is priate to align the lateral incisors - but only if a
being applied directly to the molar bands. It is limited amount of control of rotation can be
particularly useful when unilateral distal move- achieved. In a growing patient, some improve-
ment of a molar is required. In such a case only ment in the interincisor angulation may be found
a unilateral spring is necessary with the molar as a result of some proclination of the upper
on the opposite side being clasped, with a incisors during the overbite reduction stage.
flyover clasp. The upper lateral incisors have an inherent
tendency to relapse and will require perici-
sion and long-term retention following align-
Class II division 2 malocclusion ment.
Only a small proportion of such cases are
amenable to removable appliance treatment. References
Where the overbite is increased and potentially
traumatic, fixed appliances will be usually Stephens, C D . (1983) Factors affecting the rate of sponta-
necessary to establish a satisfactory interincisor neous space closure at the site of extracted mandibular
first premolars. British Journal of Orthodontics, 10:
angle. If, however, the overbite is increased but 93-97
not potentially traumatic and the upper arch
crowding is relatively mild with a good lower
arch then a class II division 2 malocclusion can Further reading
be treated utilizing a distal movement tech-
nique. Battagel, J.M., Ryan, A. (1998) Treatment changes in class
Cases where there is sufficient crowding to I and mild class II malocclusions using the en-masse
warrant premolar extractions, either in both appliance. European Journal of Orthodontics, 20: 5-15
arches or the upper arch alone are not suitable for Cetlin, N.M., ten Hove, A. (1983) Non extraction treat-
removable appliance treatment. Extraoral ment. Journal of Clinical Orthodontics, 17: 396-413
Orton, H.S., Battagel, J.M., Ferguson, R., Ferman, A.M.
support will be necessary- to achieve distal move-
ment of the buccal segments to a class I relation- (1996). Distal movemeul of buccal segments with the en-
masse appliance. American Journal of Orthodontics,
ship but normally a full-time removable appliance 109: 379-385
will be indicated as overbite reduction is likely to
Stephens, CD., Lloyd, T.G. (1980) Changes in molar occlu-
be necessary and it is difficult to achieve this with sion after extraction of all first pre-molars, a follow up
partial wear. Once the molar relationship is study of class II division 1 cases treated with removable
corrected to a class I then retraction of canines appliances. British Journal of Orthodontics, 7: 139-144