Abstract:

[Abstract] Objective  To investigate and evaluate the change and efficacy of Active -wing Appliance in patients with lingual tipping deep overbite of Angle classⅡdivision 2 malocclusion．Methods  Twenty patients with lingual tipping deep overbite of Angle class Ⅱ division 2 malocclusions were selected for our study. Among the twenty patients, fifteen are girls and five are boys, whose age are from 16.0 to 23.0 years old with average of 18.8 years old . The patients were treated with Active -wing technique and all of them were non-extracted．Cephalometric films were taken before and after treatment to assess the effect of treatment . Eleven angular and thirteen linear measurements were taken. Paired t test was performed to analyze and evaluate the effects before and after treatment. Results  Active-wing Appliance have advantage of easy operating with short treatment cycle for treatment of deep overbite of Angle class Ⅱ division 2 malocclusion. It only takes 11 months in average for the treatment. After treatment, mandibular plane angle were increased (23.00°±6.76° vs 21.59°± 5.32°)，overbite were decreased [ (1.02±0.81) mm vs (5.67±1.22) mm] to reach normal level; incisors were labial incline sig? nificantly with increased protrusion and inclination; Post treatment parameter improvement also include: U1-NA distance in? creased (4.67±1.21 ) mm vs (1.24±1.37) mm; U1-NA angle increased (24.40°±6.36° vs 11.70°±6.87°); lower incisors were significantly intruded[ (37.16±1.81) mm vs（38.90±1.84）mm]; L6-MP were extruded [(31.68±2.87) mm vs (30.38±3.45) mm]; The cuspid and molar relationships were changed from Class Ⅱ to ClassⅠ occlusion. Conclusion  The Activewing Appliance can quickly open overbite and correct incisor lingual tipping for Angle class II division 2 with lingual tipping deep overbite. It is easy to operate and has been improved as efficient and shortened treatment. Meanwhile, it also saves arch wire. The Active-wing Appliance is especially powerful for lingual tipping deep overbite. However, the deficiency in torque control of premolars might be noticed.

Key words: Active -wing Appliance, Deep overbite, ClassⅡdivision 2 malocclusion, Cephalometrics