[Effect of Twin-block appliance in the treatment of Class II and division I malocclusion: a cephalometric study in 12 patients].

PURPOSE: To quantitatively evaluate the skeletal and dentoalveolar changes induced by Twin-block appliance for treatment of Class II,division I malocclusions in growing children. METHODS: Twelve patients with Class II, division I malocclusions aged 10 to 12 years were investigated. The records were evaluated and compared with an age-matched sample of untreated Class II control subjects. The follow-up period was 12 months. Group t test was used for comparison. RESULTS: In the treatment group, the upper incisors retroclination of the upper incisors and the mandibular forward movement contributed more to the overjet reduction. The skeletal and dental effects changes molar correction were almost similar. The mandibular growth in the treatment group was 2.29 mm, greater than that in the control group. The posterior facial height and the anterior lower facial height increased by 2.28 mm and 2.58 mm respectively. On the other hand, unfavorable vertical changes were not observed. CONCLUSIONS: The treatment of Class II division I malocclusion with Twin-block appliance was effective in reducing overjet, correcting molar relationship and improving soft tissue profile. It can also enhance mandibular growth.