Choice of functional appliance therapy - Is there any difference in treatment outcome?

Abstract

AIM: To compare changes during treatment and follow-up of skeletal Class II malocclusion subjects treated with either a removable or a fixed functional appliance. MATERIALS AND METHOD: A series of lateral cephalograms obtained from a group of consecutive male patients treated with headgear-activator [removable functional appliance (RFA) group] for 12 months was compared with a matched group treated with a Herbst appliance for 6 months, followed by ‘retention’ with an Andresen Activator for six months [fixed functional appliance (FFA) group]. The patients were then followed for a further 24 months. Lateral cephalograms were obtained at start of treatment (T0) and after 6 (T6) and 12 (T12) months of treatment, and after another 24 months (T36). Interpolations were made to obtain data representing exactly the same length of observations periods. RESULTS: There were significantly more pronounced changes with the FFA than with the RFA during the initial 6 months of treatment (T0-T6). After 36 months (T0-T36) of treatment and observation, the maxilla tended to become retruded (P = 0.052) in the RFA group, whereas there was no significant change in maxillary prognathism in the FFA group, the difference between the two groups being statistically significant (P < 0.05). On the other hand the increase of mandibular prognathism in the former group was only marginally statistically significant (P = 0.052) and highly significant in the later group (P < 0.001). CONCLUSIONS: Treatment with removable and fixed orthodontic devices not only modifies growth in the short-term, but also seem to have the potential to cause permanent changes in the prognathism of both jaws.