基于牙周膜超弹性本构模型微种植支抗滑动法内收上颌前牙的三维有限元分析

发布时间：2018-04-29 16:43

本文选题：牙周膜超弹性本构模型 + 微种植支抗　；参考：《青岛大学》2017年硕士论文

【摘要】：目的探索构建牙周膜超弹性本构模型的方法,建立更精确的、更高仿真度的包含有上颌牙列、牙槽骨、牙周膜、微种植体支抗、牵引钩、弓丝、托槽在内的三维有限元模型,分别模拟直丝弓矫治技术滑动机制条件下一步法和两步法内收上颌前牙,调整微种植体植入高度和矢状向位置,观察上颌前牙的初始位移趋势,为临床提供生物力学参考。方法从青岛市口腔医院CBCT数据库中选取一例上颌前突患者的CBCT作为素材,依次应用软件Mimics Medical 17.0建立上颌牙列、牙槽骨的三维模型;应用软件Geomagic Studio 2013对已建立的上颌牙列、牙槽骨的三维模型进行曲面处理;通过软件Unigraphics NX 10对已建立的上颌牙列的牙根部分的三维模型进行抽壳0.2mm,建立牙周膜的三维模型;应用软件Solid Works依次构建简化牵引钩、上颌弓丝、简化托槽、简化种植钉的三维模型;最后通过软件Solid Works分别组装种植体支抗的矢状向位置分别位于第二前磨牙与第一磨牙之间、第一磨牙与第二磨牙之间及高度分别距牙槽嵴顶上4mm、6mm、8mm不同组合时的包含有上颌牙列、牙槽骨、牙周膜、托槽、上颌弓丝、牵引钩、种植体在内的三维模型共计12个,模拟滑动机制条件下一步法和两步法内收上颌前牙;采用文献中对2名女性成年志愿者体内牙周膜拉伸试验获得的数据在ANSYS Workbench中生成应力-应力值曲线,获取牙周膜在加载不同应力状态下杨氏模量变化的关系曲线,从而得到牙周膜的杨氏模量参数;运用ANSYS14.0软件对上述模型进行有限元分析,分析上颌前牙的初始位移情况,获取牙齿的三维初始位移云图,分别以牙冠切缘中点和根尖点作为参考点读取牙齿的三维初始位移值。牙齿初始位移分为三个方向,以X轴代表牙齿的水平方向运动趋势(向右为正),以Y轴代表矢状向运动趋势(向后为正),以Z轴代表垂直向运动趋势(向上为正),并进行比较。结果1、同一种方法内收上颌前牙时,种植体矢状向位置不变,高度增加时,各前牙牙冠初始内收量减小,各前牙的初始压入量增大;2、同一种方法内收上颌前牙时,种植体高度不变,种植体矢状向位置后移时,各前牙牙冠初始内收量增加,各前牙的压入量减小。3、种植体矢状向位置和高度均不变时,两步法内收上前牙较一步法内收上前牙,中切牙、侧切牙初始内收量更大,初始压入量更大。结论1、构建基于牙周膜超弹性本构模型的三维有限元模型的方法具有可行性;2、种植体矢状向位置的改变主要影响牙齿的内收位移方式,高度的变化主要影响牙齿的垂直向位移方式;3、一步法与两步法内收上颌前牙时,两步法可以获得更大的牙齿初始位移量。
[Abstract]:Objective to explore the method of constructing a hyperelastic constitutive model of periodontal ligament, and to establish a more accurate and high fidelity 3D finite element model including maxillary dentition, alveolar bone, periodontal ligament, microimplant Anchorage, traction hook, arch wire and bracket. The maxillary anterior teeth were retracted by one-step method and two-step method respectively under the sliding mechanism of straight wire appliance. The height and sagittal position of microimplants were adjusted to observe the initial displacement trend of maxillary anterior teeth and to provide biomechanical reference for clinical application. Methods the CBCT of a patient with maxillary protrusion was selected from the CBCT database of Qingdao Stomatology Hospital. The 3D model of maxillary dentition and alveolar bone was established by software Mimics Medical 17.0, and the established maxillary dentition was established by Geomagic Studio 2013. The 3D model of alveolar bone was curved, the 3D model of root part of maxillary dentition was extracted by software Unigraphics NX10, and the three-dimensional model of periodontal ligament was built by software Unigraphics NX10. Finally, the sagittal position of implant Anchorage was assembled by software Solid Works, and the sagittal position of implant Anchorage was located between the second premolar and the first molar, respectively. The three dimensional models including maxillary dentition, alveolar bone, periodontal membrane, bracket, maxillary arch wire, traction hook and implant were included in different combinations of the first molar and the second molar, and the height of the first molar and the second molar were respectively 4 mm to 6 mm or 8 mm above the top of the alveolar crest, including the maxillary dentition, alveolar bone, periodontal membrane, bracket, maxillary arch wire, traction hook and implant. Under the condition of simulated sliding mechanism, the maxillary anterior teeth were retracted by one-step and two-step methods. The stress-stress curves were generated in ANSYS Workbench by using the data obtained from the periodontal ligament tensile test in two female adult volunteers. The relation curves of the Young's modulus changes of periodontal ligament under different stress state were obtained, and the Young's modulus parameters of periodontal ligament were obtained, and the initial displacement of maxillary anterior teeth was analyzed by finite element analysis with ANSYS14.0 software. Three dimensional initial displacement cloud images of teeth were obtained, and the three dimensional initial displacement values of teeth were obtained by using the midpoint and the root tip point of the crown cutting edge as reference points, respectively. The initial displacement of teeth can be divided into three directions. The X axis represents the horizontal movement trend of the teeth (right is positive), Y axis represents sagittal movement (backward is positive), Z represents vertical movement (upward is positive), and the comparison is made. Results 1. When the maxillary anterior teeth were closed in the same method, the sagittal position of the implants was unchanged, and the initial adductive volume of the crowns decreased and the initial indentation of the anterior teeth increased with the increase of the height, and when the maxillary anterior teeth were retracted in the same method, When the implant height was constant and the sagittal position of the implant moved backward, the initial adduction amount of each anterior tooth crown increased, and the indentation volume of each anterior tooth decreased by .3.When the sagittal position and height of the implant were not changed, the two-step anterior tooth was retracted from the anterior teeth in one step method. In the central incisor, the initial adductive volume and the initial indentation volume of the lateral incisor are larger. Conclusion 1. It is feasible to construct a three-dimensional finite element model based on periodontal hyperelastic constitutive model. The change of sagittal position of implant mainly affects the way of tooth adductive displacement. The change of height mainly affects the vertical displacement of teeth. When the maxillary anterior teeth are retracted by one-step method and two-step method, the initial displacement of teeth can be obtained by two-step method.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R783.5

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