关键词: 上颌扩弓前方牵引, 直丝弓矫治技术, 骨性Ⅲ类错牙合畸形, 恒牙早期

Abstract:

Objective    To evaluate the treatment effects of rapid maxillary expansion and maxillary protraction and straight wire appliance technology on patients with skeletal class Ⅲ malocclusion in early permanent dentition. Methods    A total of 15 skeletal class Ⅲ patients were chosen based on the principle of maxillary retrusion in early permanent dentition and treated by straight wire appliance technology combined with maxillary protraction and rapid maxillary expansion. Results    A total of After treatment the profile improved evidently，and the normal molar relationship，overjet and overbite were established. The cephalometric analysis showed that SNA increased by（2.87 ± 1.08）°，SNB decreased by（0.61 ± 0.8）° and ANB increased by（3.47 ± 1.05）°. SN/MP increased by（2.17 ± 1.34）°，OP/FH increased by（2.97 ± 0.29）°，mandible rotated clockward and propile improved.  U1/SN increased by（5.09 ± 3.43）°，the upper incisors tipped labially，and L1/MP decreased by （2.29 ± 3.02）°. Conclusion    Straight wire appliance technology with maxillary protraction and rapid maxillary expansion is helpful and specific in treating skeletal class Ⅲ patients with maxillary retrusion in early permanent dentition.

Key words: rapid maxillary expansion and maxillary protraction, straight wire appliance technology, skeletal class Ⅲ malocclusion, early permanent dentition