【作者】 王懿；

【导师】 张少锋；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2004， 硕士

【摘要】 目的：建立人类下颌第二前磨牙、第一磨牙、第二磨牙及其支持组织的三维有限元模型，并观察下颌第一磨牙半切术后不同修复设计时牙周组织的应力分布情况，探讨半切术后固定修复治疗的可行性，并对修复方案进行优选，为临床修复治疗提供生物力学依据。 方法：①利用螺旋CT扫描及图像处理的方法，通过特定的有限元软件建立下颌第二前磨牙、第一磨牙、第二磨牙及其支持组织的三维有限元模型。②在正常的下颌第二前磨牙、第一磨牙、第二磨牙及其支持组织的三维有限元模型基础上进行材料参数改变及进行修改，得到下颌第一磨牙半切术后不同修复设计的三维有限元模型：模型3：联冠修复；模型4：联冠修复；模型5：联冠修复；模型6：单冠修复。分别在垂直载荷和斜向载荷下观察下颌第一磨牙磨牙半切术后不同固定修复设计对牙周支持组织应力分布情况。③采用联冠修复设计的三维有限元模型分析牙槽骨不同吸收程度(1／4，2／4，3／4)对牙齿牙周支持组织应力的影响。 结果：①建立了包括了牙釉质、牙本质、牙髓、牙骨质、牙周膜、松质骨、皮质骨等组织三维有限元模型，模型具有良好的几何相似性。②单冠修复时，牙周膜受力大大超过了正常的牙周膜潜力，不利于余留牙根的牙周支持组织健康，在临床上不宜提倡。单端固定桥修复时，半切后保第四军医大学硕士学位论文留牙根的牙周膜受力比接近正常的2倍，所以如果牙周组织健康条件差的情况下半切术后选择单端固定桥修复，需慎重考虑。双端固定桥设计优于单端固定桥，更好的分散了半切后保留牙根的牙周膜的负担，有利于半切术后余留牙根的牙周支持组织健康。③牙槽骨的降低会使半切术保留的健侧根牙周支持组织应力增加。 结论:①将CT扫描技术与有限元方法有机结合起来，应用于下领牙齿和下领骨三维模型是现实可行的。②磨牙半切术后修复应首选双端固定桥设计。③磨牙半切术后固定修复时应特别注意半切术后保留牙根的牙周支持组织的健康情况。更多还原

【Abstract】 AIM: To establish a 3-D finite-element model of the mandibular second premolar the mandibular first molar and the mandibular second molar and their periodontal tissues of human being. Observe the stress distribution of the reserved healthy root of the mandibular first molar with different prosthodontic design after hemisection therapy. Discuss the feasibility of fixed prosthodontic after hemisection and optimize the clinical project to provide biomechanics foundation for clinic.Methods: (1)Established a 3-D finite element model of the mandibular second premolar,the mandibular first molar and the mandibular second molar and their periodontal tissues by-means of SCT scanning technology and software of image processing and finite element analyzing program.(2)On the base of having established the 3-D finite-element model of the mandibular second premolar,the mandibular first molar and the mandibular second molar, we obtained models of different prosthodontic design through modifying the parameters of materials and bowdlerizing the model:Model combined crown prosthodontics; Model 4: combined crown prosthodontics; Model 5: combined crown prosthodontics; Model 6: single crown prosthodontics.The stress distribution of the reserved root with different prosthodontic design after hemisection therapy under the vertical loading and obliquely loading was observed.(3) On the base of the model of combined crown prosthodontic, three models of different level of alveolar bone loss(l/4, 2/4, 3/4) were generated.The stress distribution of the reserved root of the mandibular first molar were analyzed .Results : (1) Established a 3-D finite element model of themandibular second premolar,the mandibular first molar and the mandibular second molar and their periodontal tissues including enamel,dentin,cementum,cortical bone,sponge bone,pulp and mucosa. The model has favorable comparability. (2)Single crown isn’t good to the health of the reserved root because the stresses increase obviously than the normal . The stress of periodontical tissues is nearly two times than normal with free end brige. So choose it cautiously when the periodontal tissue is not healthy.The design of rigid fixed bridge is superior to free-end fixed bridge and be propitious to the the health of the reserved root by dispersing the stress of reserved root more effectively.(3) The loss of alveolar bone can increase the stress of the butments’ periodontal tissues.Conclusions: (1)It is feasible and scatheless to establish the teeth and alveolar bone by means of SCT scanning technology and software of image processing and finite element analyzing program.(2)Rigid fixed bridge is the first selection as a prosthodontic design of the mandible first molar with hemisection therapy. (3)It is important to pay attention to the health of the periodontal tissues before making prosthodontic design after hemisection therapy.更多还原