基于三维可形变模型的骨性Ⅱ类高角患者正畸前后面型分析

Analysis of three-dimensional facial changes of skeletal Class Ⅱ hyperdivergent patients after orthodontic treatment based on three-dimensional morphable model

目的本研究基于三维可形变模型法(three dimensional morphablemodel,3DMM)对骨性Ⅱ类高角患者正畸治疗前后进行软组织面型分析。方法本研究为回顾性研究,选取18例骨性IⅡ类高角减数正畸治疗的成人女性患者,对其正畸治疗前后的头颅侧位片进行软组织测量分析,对其三维面部扫描模型通过3DMM法进行分析。结果矫治前后X线头影测量与3DMM法测量的所有软组织测量指标改变量均有统计学差异,如鼻唇角(头影测量示治疗前104.12°±6.83°,治疗后112.31°±5.47,改变量为8.19°±3.83°,P<0.001;面部三维模型测量示治疗前103.81°±6.90°,治疗后112.31°±5.64°,改变量为8.23°±3.80°,P<0.001)。两种测量方法所获得的结果间无统计学差异(如两种方法相比,治疗前后鼻唇角差值相差-0.32°±0.89°,P=0.887)。通过3DMM法获得的平均人脸结果示上下唇部发生了明显的内收,其中上唇区域内收量为(2.31±0.69)mm,下唇区域为(3.38±0.67)mm。颊部至下颌角及额下区域有约1.50mm的少量内收。水平向上,矫治后下颌角点(左右分别为0.27mm与0.85mm)与颧骨点(左右分别为0.80mm与0.42mm)均有向中线集中趋势,口角点无明显变化,口裂宽度不变。垂直向上,双侧口角点均有下移(左右分别为1.24mm与0.89mm),唇下点(垂直向下移0.86mm,矢状向内收1.50mm)与软组织额前点(垂直向下移0.99mm,矢状向内收0.99mm)均向后下移动,额部更为明显。结论本研究证明拔牙矫治可使骨性Ⅱ类高角患者获得显著的唇部内收与面型改善,模型的重定位与重叠同3DMM法相结合的评价方法能更直观的展示面部软组织的三维变化。

Objective This study aimed to analyze three-dimensional(3D)facial changes of Class Ⅱ hyperdivergent patients before and after orthodontic treatment based on 3D morphable model(3DMM).Methods This study is a retrospective study.Eighteen skeletal Class II hyperdivergent adult female patients who have finished orthodontic treatment with four-bicuspid extraction were selected.The lateral cephalograms and 3D facial scan data before and after treatment were evaluated.3DMM were used for 3D facial analysis.ResultsSignificant differences were noticed for all measurements,including nasolabial angle(for cephalometric measurement:104.12°±6.83°before treatment,and 112.31°±5.47°after treatment,with the change of 8.19°±3.83°,P<0.001;for 3DMM:103.81°±6.90°before treatment,and 112.31°±5.64°after treatment.with the change of 8.23°±3.80°,P<0.001).No significant differences were revealed between the measurements of the two methods(for nasolabial angle,variation between the two changes before and after the treatment of the two methods reached-0.32°±0.89°,P=0.887).According to the average facial model gained with 3DMM,significant retraction at lip area was noticed.The average retraction at upper lip area and lower lip area were(2.31±0.69)mm and(3.38±0.67)mm respectively.Approximately 1.50 mm retraction was noticed at cheek,gonion,and menton area.Horizontally,centralized tendency was noticed for gonion(o.27 mm and o.85 mm for left and right side respectively)and zygomatic point(0.80 mm and 0.42 mm for left and right side respectively),and no significant change was found for cheilion and the width of oral fissure.Vertically,both cheilion points(1.24 mm and o.89 mm for left and right side respectively)moved downward,and labrale inferius(0.86 mm vertically and 1.50 mm sagitally)and pogonion(o.99 mm vertically and 0.99 mm sagttally)moved downward and backward,which resulted in better chin aesthetics.ConclusionsThis study indicated that significant lip retraction and facial improvement can be achieved with extraction orthodontic treatment for skeletal Class II hyperdivergent patients.The method of combined 3D model reposition and 3DMM can present 3D facial changes more visually.