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目的：本研究拟在介绍基于颧弓的三维配准评价下颌后退手术后上呼吸道形态学变化的一种方法。方法选择1例行下颌后退手术的24岁男性患者作为研究对象，分别在治疗前（T0）、治疗后1周（T1）和治疗后1年零5个月（T2）拍摄锥形束CT（CBCT）。应用MIMICS16．0软件将不同时期的CBCT扫描数据重构为颌面骨骼和上呼吸道的三维模型，然后以立体模型（STL）格式输出。在不同时期每个立体模型两侧的颧骨、颧弓和上颌骨额突上选择标志点进行点对点配准。配准完成后，在同一横截面上，测量不同时期4个不同平面上呼吸道的前后向长度（APL）、最大横向宽度（LTW）和横截面积（CSA），同时计算出口咽和喉咽的容积。最后以矢状面窗口三维模型轮廓线上不同时期下齿槽座点（B点）间距离为准测量下颌骨移动的距离。结果T1期上呼吸道有明显地减少，T2期有轻微地复发。手术后T1期下颌B点与手术前T0期下颌B点间距离较大，手术后T2期下颌B点与手术前T0期下颌B点间距离比手术后T1期下颌B点与手术前T0期下颌B点间距离略有减少。结论基于颧弓的三维配准方法可以评价手术后及手术后期上呼吸道形态学变化。“,”Objective To introduce a method of three dimensional (3 D)registration based on the zygomatic arch to evaluate upper airway morphologic changes after mandibular setback surgery.Methods One male patient aged 24 years who underwent mandibular setback surgery to correct Angle class III malocclusion was involved in this study. CBCT scans were taken before start of treatment (T0),1 week after treatment (T1 )and 1 year and 5 months after treatment (T2).The 3 Dmodels of skull and upper airway were constructed from the CBCT scans and exported as stere-olithography by mimics16.0 software.The stereolithoghraphy was registered by selecting landmark points on either side of each 3 D models on the zygoma,zygomatic arch and frontal process of the maxilla.After that,anteroposterior length,the largest transverse width and cross-section area were measured in the axial window in four planes,and the volume was automatically computed in two regions of oropharynx and the laryngopharynx.The distances of mandibular retrusion and relapse were measured between the B-points located along the contour lines of 3 Dmodels.Results A notable decrease in upper airway dimensions at T1 and a slight relapse at T2 was observed.The distance of mandibular B-point at T1 and T0 was large.The distance of mandibular B-point between T2 and T0 is slightly smaller than the dis-tance between T1 and T0.Conclusion The three dimensional registration method based on the zygomatic arch can evaluate upper airway morphologic changes after mandibular setback surgery.