牙周膜在正畸力作用下所产生的力学响应是研究正畸牙移动生物力学机制的关键，而力学响应的准确预测依赖于牙周膜的材料本构模型。前期研究中，本课题组从牙周膜微观结构出发，基于连续介质力学理论，创新性地提出了能描述牙周膜生物力学特性的横向同性的粘-超弹性模型，预实验成功提示本课题将精密测量实验与数值模拟有机结合的研究思路可行。因此本研究拟采用纳米压痕测试及自主研发的精密测量设备开展动物和人牙周膜生物力学特性体内外实验，以不同的应变率进行加载，获取蠕变、应力松弛等实验数据。根据前期建立的粘-超弹性模型对有限元分析软件进行二次开发扩展其材料模型，利用逆向有限元及最优化方法结合实验数据求解出牙周膜粘-超弹性本构模型参数。运用所获参数，对牙周膜生物力学特性体内实验进行数值模拟，通过与人体实验结果和临床实际对比修正以获得精确的人牙周膜本构模型，为制定口腔正畸治疗方案、创新矫治方法及预测治疗效果提供理论指导。

Understanding the mechanical response of the periodontal ligament to orthodontic force is critical for studying the biomechanical mechanism of orthodontic tooth movement. Accurate prediction of periodontal ligament response to force, however, relies on a material constitutive model of the periodontal ligament, which is yet to be developed. In preliminary studies, based on continuum mechanics theory, our group carefully examined the microstructure of the periodontal ligament, then innovatively established a new transversely isotropic visco-hyperelastic model to describe the biomechanical properties of the periodontal ligament. These proof-of-concept studies confirmed that it is feasible to combine precise experimental measurements with numerical simulation for model construction. Following this approach, the present study intends to use nanoindentation tests and self-developed precision measuring equipment to carry out experiments on animal and human periodontal ligaments in vivo and vitro. Experimental data such as creep, stress relaxation will be obtained by loading periodontal ligament specimens at different strain rates. Based on the established visco-hyperelastic model, we will further develop the material model of finite element analysis software through writing a user-defined material subroutine. The experimental data is used to obtain parameters for visco-hyperelastic constitutive model of the periodontal ligament by means of the inverse finite element analysis and optimization method. Using the constructed model, in vivo biomechanical properties of the periodontal ligament will be simulated. Then, to further optimize the accuracy of human periodontal ligament constitutive model, the results of numerical simulation will be adjusted by comparison with data from experiments and clinical practice. This constitutive model, after being verified, is expected to provide theoretical guidance to develop orthodontic treatment plan, create new orthodontic method and predict the therapeutic effect.