反向Twinblock矫治器矫治替牙期功能性Ⅲ类错的临床研究

Preliminary Clinical Study of Reverse Twinblock on Correcting Skeletal Class Ⅲ Malocclusion in Mixed Dentition

目的:探讨反向Twinblock矫治器矫正替牙期功能性Ⅲ类错的硬组织改变。方法:采用Twinblock矫治器矫正替牙期功能性安氏Ⅲ错8例,对矫正前后的头颅侧位片进行X线头影测量分析。结果:矫正后前牙覆盖平均增加6.66mm,∠ANB平均增加2.68°,PNS-A′长度平均增加1.63mm;下颌升支长度平均增加5.16mm,∠NSAr增大0.98°;上中切牙唇倾度加大,位置前移;但下颌体长度的改变、下颌平面角改变及后前面高比的改变无统计学意义。结论:反向Twinblock矫治器可使上切牙唇倾、位置前移;在治疗期间能促进上颌骨的发育,抑制下颌体的发育,促进下颌升支的增高;反向Twinblock矫治器的对上下颌骨的长期作用有待进一步研究。

Objective： To investigate the hard tissue changes of functional class Ⅲ malocclusion corrected with reverse Twinblock. Method： Eight cases of Class Ⅲ functional malocclusion in mixed dentition treated with reverse twinblock, were selected. Lateral cephalometric radiographs taken at the begining and end of the treatment were assessed. Result： After treatment, the average overjet increased 6.66mm, the average ANB angle increased 2.68°, the average length of PNS - A＇increased 1.63mm, the average length of Ar- Go increased 5.16mm, the NSAr angle increased 0.98°, and the upper incisor proclined, but the change of the length of mandibular body, the mandibular plane angle, and the ratio of posterior and anterior facial height, had no statistical meaning. Conclusion： During the treatment of skeletal Class Ⅲ malocclusion in mixed dentition, the reverse Twinblock could procline the upper incisor, accelerated the development of maxillary and mandibular ramus, and restrained the development of mandibular body. A randomly allocated prospective study was required to fully evaluate the bone efficacy of this appliance.