安氏Ⅲ类错伴开行双颌手术对颏部形态的影响

目的:针对安氏Ⅲ类错伴开患者,在计算机上重建头颅三维模型并模拟双颌正颌手术,通过对开距离以及术中术后颏部的角度测量,分析开距离与颏部角度变化的关系,为术前预测颏部形态改变提供相关定量参考。方法:对在我院就诊的共20例安氏Ⅲ类错伴开患者进行研究,统计其开距离。计算机将三维CT影像重建出头颅模型,模拟上颌Lefort Ⅰ型截骨前徙,下颌SSRO旋转后退成型术,测量术中及术后面角和Y轴角的大小变化,分析其与开距离之间的关系。结果:安氏Ⅲ类错伴开患者行正颌手术后面角均增大,并且开距离与面角变化值成正相关,开距离越大手术后面角改变越大。经过统计学分析,得到开距离X与面角变化量Y1的直线回归方程,为Y1=0.82+2.06X。对于Y轴角的测量表明,开患者的Y轴角在正颌手术后均有不同程度的减小,开距离越大减小的越多,即开距离与Y轴角的减小量成正相关。统计学分析,开距离X与Y轴角变化量Y2的直线回归方程Y2=0.68+1.25X。结论:安氏Ⅲ类错伴开患者,行双颌正颌手术后,其开距离与颏部形态变化有相关性。此相关性为预测和分析正颌手术中颏部形态的变化趋势提供定量依据。

The affect to the form of chin in mesioclusion with open bite operated by orthognathic surgery

Objective Focus on mesioclusion with open bite,reconstruction of three-dimensional skull and simulation of orthognathic surgery on computer,measure the distance of open bite and in-surgery and after-surgery chin angle.Analysis the relation of open-bite distance and chin angle.Provide quantitative reference to the change of chin form before surgery.Methods Tudy in the 20 mesioclusion with open bite patients in our hospital,count their distance of open bite.Reconstruction of skull with three-dimensional CT image in computer.Simulation of maxillary Lefort I osteotomy and mandibular SSRO.Measure the change of NP-FH angle and Y-axis angle,and analysis their relation with open-bite distance.Results NP-FH angle of mesioclusion with open bite patients increases after surgery.The open-bite distance and NP-FH angle change have a positive correlation.By the statistics analysis,we get a linear regression equation:Y1=0.82+2.06X.On the other hand,to the Y axis angle change,there is also a positive correlation and Y2=0.68+1.25X.Conclusion Mesioclusion with open bite patients after orthognathic surgery,their open-bite distance has correlation with chin form.This correlation can provide quantitative reference for prognosis and analysis of orthognathic surgery.