Cephalometric Evaluation on Class II Patients Treated With Detachable Headgear-activators

Objectives: To evaluate the cephalometric changes on skeletal Class II Division I patients (ANB°Ý5°ã) treated with the new detachable headgear-activators. Methods: 25 skeletal class II division I patients (11 males, 14 females ) were treated. The mean age of pretreated patients (T1) was 10.8 years, that of posttreated patients (T2) was 13.4 years. A detachable headgear-activator was used to correct the upper-lower molar relationship from class II to class I. The patients were instructed to wear the appliance over 12 hours a day with a continuous force of 600 cN. Furthermore, fixed appliances were used to align the teeth. The changes of cephalometric analysis between T1 and T2 were analyzed. Results: The mean of SNA and SNB of posttreated patients reduced 0.8°ãand 1.7°ã (P<0.05) respectively, compared with that of pretreated patients. Significant reduction in overject (4.3mm, P<0.01) and overbite (2.7mm, P<0.001) were observed. The mean change of relative distance between upper and lower molars was increased 3.5mm. Conclusions: the forward growths of mandibulae were improved, but not in maxillae. The upper-lower jaw relationships were improved either in anterior segment or posterior segment. The main effect of the detachable head gear-activator was to restraint the forward growth of maxillae.