face mask ; favorable profile ; bialveolar protrusion
Abstract
Skeletal Cl III malocclusion is an orthopedic appliance mainly used for growing children with maxillary undergrowth, which largely entails skeletal Cl III malocclusion. It improves anterior crossbite and maxillary position and thus, enables patients to attain favorable Profile but often involves unfavorable profile with protrusive upper and lower lips. Therefore, if orthodontists have knowledge of which condition helps obtain favorable occlusion and profile, they are able to predict the prognosis and limitation of the treatment. This study was done in order to help obtain favorable Profile after treating growing skeletal Cl III children. In the study, we classified childern into two groups, the one with favorable profile(Group 1, n=12) and the other with unfavorable profile(Group 2, n=14) and, with retrospective study using pre- and post-treatment lateral cephalogram, drew the following conclusions. 1. As patients had more serious labioversion of upper incisors, they were more unlikely to have favorable profiles after the treatment. Protrusion of prosthion, which was related with maxillary incisors, also affected profiles. 2. As the NL-ML angle before the treatment was small, it was more likely to get favorable profile. 3. As the degree of lower lip protrusion was high, it was likely to have bialveolar protrusion after the treatment. 4. As the degree of downward and backward rotation of mandible was high, it was likely to get unfavorable profile.