正颌手术对颌面硬组织对称性改变的三维评估

目的 通过锥形束CT（cone beam computed tomography,CBCT）研究正颌手术对成人骨性Ⅲ类错牙合伴颜面部不对称患者治疗的疗效。方法 选择正畸临床成人骨性Ⅲ类错牙合伴颜面部不对称患者20例，20例患者均采用正畸-正颌联合治疗的方法，在正畸前（T0）和正颌手术后6个月（T1）后使用CBCT对患者进行三维扫描获得颅面部DICOM数据，采用Dolphin 11.0对颌骨进行三维重建，选择描述颌骨骨性结构特征的20个点进行描记，测量分析20个变量。结果 20例颜面部不对称患者，正颌手术改善上颌骨下部水平向及矢状向的不对称性，双侧下颌体的长度及下颌支的倾斜度得到纠正。结论 正颌手术能有效改善成人颜面部不对称，对成人骨性Ⅲ类错牙合伴颜面部不对称患者的改善主要表现在上颌骨下部水平向及矢状向的对称性改善，以及下颌体长度不协调的纠正，正颌手术前三维测量对正颌治疗方案的制定及预后的判断至关重要。

Three-dimensional evaluation of orthognathic operation on the maxillofacial hard tissue symmetry change

Objective To study the effectiveness of orthognathic operation on skeletal Class Ⅲ malocclusion in adult patients with facial asymmetry towards the symmetry of maxillofacial hard tissue utilizing CBCT.Methods 19 adult patients of skeletal ClassⅢmalocclusion with facial asymmetry were selected,and all patients were treated with orthodontic orthognathic therapy.CBCT was used to perform 3D scanning on patients to obtain DICOM data before the orthognathic operation (T0) and six months after the orthognathic operation (T1).Dolphin 11.0 was utilized to rebuild the jaws in 3D,16 points describing the maxilla and mandible structure characteristic were chosen,and 20 variables were analyzed by statistics.Results The orthognathic operationwas able to ameliorate the horizontal and saggital asymmetry of the lower parts of inferior part of maxillary for the study group of 19 patients.The length of mandibularbody on both sides and the gradient of mandibular branch were both corrected.Conclusions The orthognathic operation is able to effectively improve adults′ facial asymmetry.The correction on adults with facial asymmetry skeletal Class Ⅲ malocclusion patients is restricted to improving the horizontal and saggital asymmetry of the lower parts of upper jaws as well as the incoherence in the length of mandibular.Accurate 3D measurements before orthognathic operationare critical to making the treatment plan and prognosis judgment.