Purpose: This study was to develop an intraoral Class Ⅲ orthopedic appliance using attractive magnetic forces, and investigate the effect of magnetic orthopedic appliance (MOA-Ⅲ) on skeletal and dental structures in mild skeletal Class Ⅲ children.
Methods: Thirty patients (12 boys and 18 girls) with mild skeletal Class Ⅲ jaw discrepancies were treated with MOA-Ⅲ. The average age was 9 years 3 months at the beginning of the treatment. The mean treatment period was 6.6 months. A paired t test was carried out to evaluate 40 parameters measured on cephalometric radiographs. Another 18 untreated patients (7 boys and 11 girls) according to upper criteria served as control group. SPSS15.0 software package was used for data analysis.
Results: The MOA-Ⅲ produced significant positive changes in maxillomandibular relationship. The maxilla was displaced anteriorly with clockwise rotation. The mandible showed slight downward and backward rotation. No significant changes were displayed in the length of the mandibular body and mandibular ramous. Significant labial tipping of the upper incisors and lingual tipping of lower incisors were noted after treatment. The measurement of soft tissues indicated that the upper lip moved forward and the lower lip retruded backward. In control group, most of the cephalometric measurements were not significantly changed except for some mandibular skeletal measurements and soft tissue measurements.
Conclusions: By comparing to the untreated control, this type of magnetic orthopedic appliance is effective in the early treatment of mild skeletal Class Ⅲ malocclusion children.