下颌骨体部牵张成骨的三维有限元研究

目的：用三维有限元法研究下颌骨体部不同牵张方向对下颌骨应力分布与位移的影响。方法：采用螺旋CT技术与计算机软件相结合，建立人下颌骨牵张成骨三维有限元模型。测量不同加载条件下，下颌骨的Mises应力、颏顶点和右侧下颌角点的位移。结果：建立了人下颌骨牵张成骨三维有限元模型。Mises应力集中在加载部位。双侧、与聒平面平行方向加载应力大，位移趋势为对侧前上方；单侧、与下颌骨下缘平行方向加载应力小，位移趋势为对侧后下方。单侧加载下颌骨向对侧偏斜多，双侧加载矢状向位移趋势大。结论：临床上应根据矫治需要，确定理想的牵张方向。

A three-dimensional finite element study on the distraction of mandibular corpus

Objective: To study the stress distribution and displacement of different distract directions on mandibular corpus by finite element method. Methods: A young man with normal occlusion was adopted for CT scanned transverse section which was then used to establish the model by computer software. Evaluations of Mises stress as well as the displacement of gnathion and gonion under different loads were made. Results: A three-dimensional finite element model of human mandibular distraction was constructed. Mises stress primarily accumulated in distracted areas and were higher under bilateral distraction parallel to the occlusal plane.The mandible showed upward and forward displacement. Distractions parallel to the mandibular body made the mandible go backward and downward. Transversal displacement to the opposite side were greater during unilateral distraction, while displacement in the saggittal plane were greater during bilateral distraction. Conclusion: Ideal distraction direction should based on the clinical needs.