咀嚼肌对牙齿咬合力影响的生物力学模型

Masticatory function has a very important impact on dentofacial development and remodelling of dentofacial morphology.However masticatory function is so complicated and varies a lot among the people. Current research can only analyze the distribution of Stress-Strain in the periodontal tissues under given bite force.Effect of individual morphology,strength and movement of masticatory muscle on dentition was neglected. Research on the relationship between masticatory function and morphology is very limited because of the lack of effective method. With the development of 3D virtual reality technique, modern 3D finite element method and dynamic biomechanics, it is now possible to bring the study of the effect of dentofacial system function on morphology to the next level. This study is plan to explore the method how to accurately attach the masticatory muscle to hard tissue based on MRI resourced image and our previous 3D model of dentofacial hard tissue.A virtual reality model of the masticatory systme including upper and lower jaws,full dentition,TMJ with ligment and masticatory muscle et al.Based on this model biomechanic properties of masticatory muscles,accurate mandibular movement and distribution of bite force of different jaw position will be studied.Such datas will be integrated into the virtual reality model.Validity of this biomechanical model will be verified by repeated tests.

咀嚼功能对牙颌发育及颅面形态的改建具有十分重要的意义，然而咀嚼功能十分复杂，因人而异，现有研究手段只能假定咬合力后分析牙周的应力应变分布，忽略了个体咀嚼肌形态、强弱，咀嚼运动等对牙列的影响。由于缺乏研究手段，正畸界对咀嚼系统功能与形态关系的研究十分有限。随着计算机三维虚拟现实技术、现代三维有限元技术及动态生物力学技术的发展，深入探讨口颌系统功能对形态影响的研究已成为可能。本研究拟在我们以往建立的牙颌面硬组织三维数字模型的基础上，借助于核磁共振获取咀嚼肌的三维数字影像，研究其准确附丽于硬组织数字模型的方法，从而形成包含上下颌骨、全口牙齿、颞颌关节、咀嚼肌、关节韧带等软硬组织结构的咀嚼系统虚拟现实模型；在此基础上，研究咀嚼肌的生物力学性能、准确记录下颌运动、实际测量咬合力在不同颌位时的（牙合）力分布，将上述结果以数学模型的方式赋予咀嚼系统的虚拟现实模型，并通过重复实验验证该生物力学模型的可靠性

咬合力是正畸矫治力的重要组成部分，其大小、方向和分布受到个体化咀嚼系统的影响。本项目根据三维激光扫描牙列影像及螺旋CT扫描颅面部影像，使用Rapidform和Amira三维图形处理软件进行牙齿、颌骨和肌肉的影像分割、重建和配准，建立了包括上下颌骨、全口牙列和四对咀嚼肌（颞肌、咬肌、翼内肌、翼外肌）的三维静态咀嚼系统模型，并与Arcus digma记录的个体化三维六自由度下颌运动数据相结合，利用Matlab软件计算出下颌骨运动中的平移量和旋转量，导入Amira软件中虚拟再现咀嚼系统模型开闭口、前伸和侧方的下颌功能运动。咀嚼系统模型经Geomagic studio图像处理，进一步导入Ansys软件中建立三维有限元模型，分析了咀嚼肌随下颌运动的形态变化。该研究初步建立了基于三维影像、下颌运动数据和有限元方法的个体化功能性咀嚼系统模型，为进一步探讨咀嚼肌对咬合力影响的生物力学分析奠定基础。研究成果发表在“中国科技论文在线”上。