1.北京理工大学 宇航学院 力学系 生物力学实验室;2.北京大学第三医院骨科
1.Biomechanics Lab,Department of Mechanics,School of Aerospace Engineering,Beijing Institute of Technology;2.Department of Orthopaedics,Peking University Third Hospital
目的 深入研究正畸力和动态咬合力作用下牙槽骨内的液体流动情况，为阐明牙槽骨结构重建的调控机理提供基础数据。方法 构建了正畸牙齿移动的大鼠动物模型，利用micro-CT技术扫描并三维重建得到了牙齿-牙周韧带-牙槽骨整体及第一磨牙近中牙根根尖及颈缘处牙槽骨的真实几何结构。进而计算了正畸力或咬合力作用下牙槽骨的应变分布，并以此为基础利用流固耦合的数值模拟方法分析了咬合与正畸加载下不同位置处牙槽骨内液体的流动情况。结果 正畸及咬合力作用下，牙槽骨内液体流速主要分布在0到10 µm/s，流体剪应力主要分布在0到10 Pa，高流速及高流体剪应力出现在孔隙内的固液交界面上。根尖处牙槽骨表面的流体剪应力水平高于颈缘处牙槽骨。结论 正畸力及咬合力的联合作用在牙槽骨的不同位置引起不同水平的流体剪应力，进而可能刺激牙槽骨骨小梁表面的细胞发生响应，并最终调控牙槽骨结构重建和发生正畸牙移动。
Objective To study the fluid flow within alveolar bone under orthodontic and occlusal loading is important for understanding the regulatory mechanism of bone remodeling during orthodontics. Methods An animal model for orthodontic tooth movement on rats was first constructed. Finite element model of tooth-periodontal ligament-alveolar bone was established based on micro-CT images and the strain field in alveolar bone under orthodontic or constant occlusal loading was analyzed. Then finite element model of alveolar bone was constructed from the bone near the cervical margin or apical root of mesial root. The fluid flow in this model under orthodontic and cyclic occlusal loading was further predicted by using fluid-solid coupling numerical simulation. Results The fluid velocity within alveolar bone cavity mainly ranged between 0 and 10 μm/s, and the fluid shear stress (FSS) was mainly between 0 and 10 Pa. FSS on the surface of alveolar bone near the apical root was higher than that near the cervical margin. Conclusions FSS with different levels could be produced at different location within alveolar bone cavity under orthodontic and cyclic occlusal loading, which might further activate biological response of bone cells on the surface of trabeculae and finally regulate the remodeling of alveolar bone and movement of orthodontic tooth.