Abstract:
Background For patients with skeletal class III malocclusion due to underdevelopment of maxilla, orthodontic treatment can be achieved through maxillary protraction in clinical practice, but its efficacy for patients at later period of pubertal peak is controversial. Objective To measure the changes of facial hard tissues before and after maxillary protraction in patients with skeletal class Ⅲ malocclusion at later period of pubertal peak and analyze the efficacy of the protraction. Methods Patients with skeletal class Ⅲ malocclusion at later period of pubertal peak (CVM Ⅴ-Ⅵ stage) who visited the Department of Orthodontics, the First Medical Center, Chinese PLA General Hospital from 2017 to 2023 were treated with a pad intraoral appliance and an extraoral double-rod maxillary anterior distractor. Before and after treatment, lateral cephalometric radiographs were taken to measure and analyze the changes of facialbone and dental indices. Results A total of 31 patients, 19 males and 12 females, with an average age of (12.7±1.1) years and an average treatment course of (8.4±1.9) months, were included in this study. After maxillary protraction treatment, the sagittal position indices of maxilla, SNA increased by 2.66°±1.29° (P<0.001), ss/OLP increased by (3.70± 1.95) mm (P<0.001), Or/OLP increased by (1.44±1.94) mm (P<0.001), and Ptm/OLP increased by (0.83±1.49) mm (P=0.004). The inclination of upper anterior teeth (U1-SN) increased by an average of 1.16°. The inclination of lower anterior teeth (IMPA) decreased by 0.75°±4.83° (P=0.397). Conclusion The application of the pad intraoral appliance combined with extraoral doublerod maxillary anterior distractor can effectively promote maxillary advancement of patients with skeletal class Ⅲ malocclusion at later period of pubertal peak, and control the lip inclination of upper anterior teeth and the tongue inclination of lower anterior teeth well.