【作者】 吕纯洁；

【导师】 董湘怀；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2005， 硕士

【摘要】 牙齿冠部充填修复是一种常见的牙体病治疗技术,充填修复后的牙齿常常在使用中发生医源性折裂。如果能采用科学的方法,有针对性地设计出合理的充填修复方案来配合临床操作,就可以最大限度地减少牙齿医源性折裂,大大提高充填修复后患牙的使用寿命。随着计算机技术的进步,有限单元法成为生物力学研究中的重要方法之一,生物力学在口腔领域的应用,为牙齿治疗方法的评价以及修复用材料的研究、开发和使用提供了力学基础。以有限元为代表的数值分析方法的发展,可对复杂几何形状物体建模,根据需要求得整体或局部的应力和位移值及其分布规律; 在维持原模型几何形状不变的情况下,可自由改变加载与边界条件等力学参数,对不同情况下的应力大小和分布变化进行对比分析。本文系统地介绍了逆向建模和有限元网格划分方法。在通用三维设计软件UG 中按照逆向建模方法,以CT 扫描所得到的JPG 图片文件为基础,建立了上颌第二磨牙的CAD 模型; 在有限元分析软件ANSYS 中进行网格划分,得到三维有限元分析模型。研究了牙齿在十种典型载荷作用下不同的应力状态,根据应力云图总结出牙齿在一般情况下的应力分布规律; 研究了牙齿在不同充填材料、不同窝洞洞形和不同窝洞大小情况下修复后,承受不同载荷时的应力状态,根据应力云图总结出相应充填修复后牙齿承载能力的变化规律。为了验证有限元方法的可靠性,本文以激光散斑法为基础设计实验,测量出牙齿在不同加载方式和大小情况下的变形,和三维有限元软件分析数据进行比较,得到了比较一致的分析结果。更多还原

【Abstract】 The packing and repair of the tooth grown is a usual technology in the treatment of diseases of the tooth. The packed and repaired tooth, however, often get fractured medically. In order to farthest reduce the possibility of medical fracture and enhance the longevity of the packed and repaired tooth, we try to adopt some scientific methods and make a rational scheme, pertinently for the clinic operation. With the rapid development of the computer science, the Finite Element Method has become a significant method in the research of the biological mechanics. The application of the biological mechanics in the stomatology supplies some mechanical basis for the evaluation of the tooth treatment and the research, development and usage of the materials used for repair. The numerical analysis methods like the Finite Element Method are employed to make modeling for the complex geometric shape objects and get the integral or local stress data, displacement values and their distributing disciplinarian. Meanwhile, some reference analysis could be made in different stress and distribution in the case that the mechanical parameters like loads and boundary condition are freely changed in the same model shape. A converse modeling and Finite Element grid division method is systematically introduced in this paper. The CAD model of the second molar of the upper jaw is conversely established with the help of UG, a kind of general CAD software and on the basis of the JPG pictures gained from the CT scanning. And then the 3-D Finite Element analysis model is built after the grid division via ANSYS, a type of Finite Element analysis software. The stress state of the tooth under ten different loads are studied, which then leads to a general stress distribution disciplinarian according to the stress nephogram. Besides, the stress state of the repaired tooth in different packing materials, cavity shapes and cavity capacities are discussed when enduring different loads, and the change disciplinarian of the enduring ability in corresponding packing is also obtained on the basis of the stress nephogram. For the sake of validating the reliability of the Finite Element methods, an experiment is designed adopting the Laser Interferometry method. The transfiguration of the tooth in different loads are measured and compared with the analysis data from the 3-D Finite Element software. Finally, a fairly accordant analysis result is acquired.更多还原