The Therapeutic Effect Of Mandibular Retrognathia Teenagers By Invisible Appliance

The purpose of this study was to idendify the torque control and bone effect by invisible appliances and twin- block treatment for Class II skeletal malocclusion teenagers. This study included a total of 60 adolescent patients with mandibular retraction, 29 cases were treated with invisible appliances while 31 cases weretreated by twin-block. There were no statistically significant differences in gender and age between the two groups. The average duration of invisible appliance treatment is 10.3 months, and the average duration of twin-block treatment is 9.7 months. We collected the lateral radiographs of patients before and after orthodontic treatment, and analyzed the changes in ANB and SNB to observe whether the orthodontic treatment can effectively promote mandibular growth. We also analyzed the changes in L1-MP to explore the dental effects produced during the treatment. The results showed that the SNB of the invisible appliance group increased by 0.5 ° and the L1-MP increased by 3.7 °, while the SNB of the twin-block treatment group increased by 0.6 ° and the L1-MP increased by 4.4 °. This suggests that using invisible appliance or twin-block treatment for adolescent with mandibular retrognathia can achieve similar bone effects, using twin-block appliance may cause more lower anterior lip inclination, while invisible appliance is relatively more effective in controlling the torque of the lower anterior teeth.