拔牙与非拔牙的骨性安氏Ⅲ类双颌手术前后的硬组织变化

Hard tissue changes between extraction-and nonextraction-group in patients with skeletal Class Ⅲ malocclusion by orthognathic treatment

目的:探讨已行双颌手术的骨性安氏Ⅲ类错患者治疗前、正颌手术前正畸后和治疗完成后拔与不拔上颌第一前磨牙的上、下颌骨硬组织结构差异。方法:研究对象为均已行上颌骨Le Fort I型前移和下颌骨矢状劈开后退术的骨性安氏Ⅲ类错畸形伴上颌骨发育不足和下颌骨发育过度的患者。研究对象被分成两组:术前正畸拔除上颌第一前磨牙组15例,未拔牙组16例。摄取治疗前(T1)、正颌手术前正畸后(T2)、治疗完成后(T3)的头颅侧位定位片分析测量9个指标值,采用SAS 8.02软件包对数据进行团体t检验。结果:治疗前(T1)拔牙与非拔牙组上牙槽角(SD-SN)有显著差异(P<0.05)。正颌手术前正畸后(T2)下中切牙角(L1-MP)和覆盖有显著差异(P<0.05)。治疗后(T3)下中切牙角(L1-MP)有显著差异(P<0.05)。其他各测量项目均无统计学差异,P>0.05。结论:拔牙组在治疗前骨组织的结构形态上上牙槽骨较非拔牙组更前突,通过术前拔牙正畸内收上前牙长轴后得以改善。正颌手术前正畸后拔牙组下前牙去代偿较非拔牙组更明显,下前牙更直立。

PURPOSE：The aim of this study was to evaluate the hard tissue changes between extraction-and nonextraction-group in patients with skeletal Class Ⅲ malocclusion before and after orthognathic treatment.METHODS：Thirty-one patients with maxillary hypoplasia and mandibular prognathism were divided into two groups：a group that consisted of 15 cases with extraction of maxillary premolar and a group that consisted of 16 cases without extraction.All patients were performed maxillary Le Fort I osteotomy and sagittal split ramus osteotomy（SSRO）.Data were collected from standardized lateral cephalometric radiographs taken at pretreatment（T1）,preoperation（T2） and the completion of treatment（T3）.Cephalometric analysis included 9 patients.The data were compared at T1,T2 and T3,respectively,with SAS8.02 software package for grouped t test.RESULTS：There was no significant difference in hard tissue morphology at T1,T2,T3 between extraction-and nonextraction-group（P0.05）,except upper alveolar anglar（UD-SN） at T1,overjet at T2,L1-MP at T2 and T3（P0.05）.CONCLUSIONS：Before treatment,upper anterior alveroar bone in extraction group protruded more than nonextraction-group.By extraction and preoperative orthodontic treatment,protrusion was improved before orthognathic surgery.Decompensation of lower incisor in extraction group was greater than nonextraction-group by increasing reverse overjet.