有限元法探讨犬下颌单侧不全截骨牵张时非牵张侧位移趋势

Discussing displacemental trend on nontractional side of canine mandible with finite element method when distraction osteogenesis with unilateral incomplete osteotomy

目的分析犬下颌单侧不全截骨牵张成骨有限元模型,计算下颌骨非牵张侧各部分在牵张过程中位移状况。方法模拟犬下颌单侧不全截骨牵张成骨,当滑动骨块受力未被牵开和被牵开时观察非牵张侧关节、下颌角、喙突及牙齿等6个标志点的位移情况。结果当滑动骨块未被牵开时,非牵张侧下颌骨各标志点所受Von Mises应力为0,在空间X、Y、Z三轴位移均为0;当下颌骨滑动骨块被牵开1 mm时,各标志点在空间X、Y、Z三轴均有位移。结论在行半侧不全截骨牵张成骨时,从牵张侧观察,非牵张侧下颌骨在矢状平面上有以髁突顶点(横嵴中点)为中心的逆时针旋转趋势,而在冠状平面上则表现为向牵张侧的近似平行的移动。

Objective To discuss the trend of displacement on the side of nondistraction when distraction osteoge-nesis with unilateral incomplete osteotomy of canine mandible.Methods The method of finite element analysis was used to simulate distraction osteogenesis with unilateral incomplete osteotomy and the displacement of six marked point such as the temporomandibular joint and the angle of mandible and coracoid process and teeth were observed on nondis-tractional side when the transport disc was distracted with a distance and without a distance.Results When the trans-port disc was distracted without a distance,the Von Mises stress was 0 in the six marked point of nondisractional side and their displacement in 3 dimensions（X,Y,Z axis） was 0.When the transport disc was distracted with 1 mm width,all marked point had some displacement.Conclusion When distracted and observed from the side of distraction,the mandible at the side of nondistraction has the trend of contrarotation round the center of the transverse ridge mid-point of condyle process on the plane of sagittal,whereas it has the trend of parallel movement approximately in the direction of opposite side on the plane of coronary.