【作者】 钱英莉；

【导师】 樊瑜波；

【作者基本信息】 四川大学 ， 固体力学， 2003， 硕士

【摘要】 错(牙合)畸形的矫治主要通过矫治器对错位牙施以矫治力，使错位牙得到矫正，从而恢复和重建平衡的(牙合)受力关系。通过对正畸力作用下牙体、牙周组织及牙槽骨的应力应变分析研究，对研究正畸牙齿的移动规律有重要的指导意义。正畸牙及牙周的应力分析在国内外都有较多的研究报道，但是目前这一领域的研究多局限于加载的瞬间、即初始状态的应力分析，这样的应力分析只研究了正畸牙在受正畸力的某一个时刻的应力分布，并以此为依据分析临床上牙移动的矫治力系统是否合理。这种应力分析是对某个瞬间的应力分析，属于静态的分析，与临床正畸治疗中的实际情况有较大出入。临床正畸治疗中的牙移动是一个持续的、动态的过程，正畸治疗中牙齿的受力是持续的并随着牙齿的位置的改变(牙移动)而发生变化，也就是说牙齿的应力状态是一个动态变化的分布。 在矫治力作用下，牙周组织应力的大小和分布对牙齿的移动具有决定作用，研究各种矫治力作用下牙周支持组织的应力大小和分布，对于进一步研究牙齿移动过程中牙周膜、牙槽骨改建及牙根吸收的机制，以便临床上正确掌握和使用合适的矫治力具有十分重要的意义。本文首先建立了包括上颌尖牙牙体、牙周膜、牙髓、牙槽骨的三维有限元模型，分析不同加力方式下牙周组织中的应力分布。 本文用上述模型模拟一个治疗周期(四个星期)上颌尖牙整体移动和倾斜移动的动态过程，并与实际移动测得的曲线进行对比。本研究应用有限元法分析正畸力作用下尖牙牙周组织的应力分布，用VB编程确定在此应力状态下牙齿在一定时间内的移动距离和移动后的位置。计算尖牙在新位置且力衰减情况下牙周组织的应力分布，确定下一时段尖牙移动的位置。从而计算出一个治疗周期内尖牙的移动曲线，为预测正畸中牙齿的移动趋势提供理论指导。更多还原

【Abstract】 Orthodontic treatment for dental malocclusion is to apply forces to dental arch by use of appliance, and the malocclusion treatment can be obtained by ways of correcting the inter-maxillary occlusal relations and reconstruction of occlusal biomechanical equilibrium in general. It is important to analyze the stress distribution in tooth, periodontal ligament and alveolar bone under orthodontic forces. There are many reports on periodontal tissue stress analysis, but at present stress analysis for tooth movement is confined to instant loading status. And the stress distributions are usually used to give an assessment of the clinical orthodontic forces. In fact, this is the static analysis and it is far from the fact orthodontic therapy. Clinical therapy is a continuous and dynamic process, and orthodontic force is continuous and changed with the tooth position.The stress distribution in periodontal tissue plays a very important role in determining tooth movement. And this is also useful for understanding the reconstruction of periodontal membrane and alveolar bone or tooth root absorb. The results can be used as instructions for the clinical usefulness of the theories of optimal force and differential force. A three-dimensional canine model including alveolar bone, periodontal membrane and pulp were obtained to analyze the stress distribution under differential orthodontic force.The stress values in different stages in a long-time movement of canine retraction were calculated under different kinds of orthodontic tooth movement: distal tipping movement and distal translation then the results were contrasted withpractical curve. A particular program and the stress distribution were used to calculate the movement distance and find the new position of canine during a week. Then the model was rebuilt at the tooth new position with force lost. The model was used as initial state then above process was done again .At last a curve of canine movement in a therapy periods was obtained, and this can be used as instructions for orthodontic treatment.更多还原