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目的本课题利用三维有限元法,模拟上颌中切牙根切术后模型,并进行应力分析,继而评估不同咬合形态造成的不同咬合力方向,可能对此带来的影响。以期对临床病例的选择和预后提供理论依据。方法建立上颌中切牙三维模型,继而根据根切术基本要求,模拟出根切术后模型和根切术骨完全愈合后模型,计3个模型;在Ansys Workbench有限元软件中按照一定的载荷条件,观测根切术前、后,不同受力方向下的应力分布和大小,并进行对比分析,了解应力变化趋势。结果当加载情况相同时,根切术后即刻受力,牙颈部以及整体应力的最大值、分布情况,最大位移值均较完整牙齿增大,当根尖骨组织愈合完全,上述参数又有改善,但仍高于完整牙齿状态。而当所有条件一致时,载荷方向与牙长轴所成角度越大,整体应力水平越大,应力集中区域范围越大,总体位移值也越大。结论根切术后即刻至根尖牙槽骨质完全愈合之前,较完整牙齿生物力学稳定性下降。在完全愈合后,稳定性又获得一定程度的改善。所以根尖区骨质的再生是关乎根切术成败也是维持术后牙齿机械稳定性的关键。咬合状态使患牙承受水平力较大,根切术后带来的应力增加越大,选择根切术作为治疗方案时建议将咬合形态纳入考虑因素,避免造成应力集中,松动等不良后果。
OBJECTIVE: This study used the three-dimensional finite element method to simulate the model of maxillary central incisor after root cutting and performed stress analysis to evaluate the possible influence of different occlusal forces caused by different occlusal patterns. In order to provide a theoretical basis for the selection and prognosis of clinical cases. Methods The three-dimensional model of maxillary central incisor was established. Then according to the basic requirements of radical resection, three models were obtained after the model of radical resection and the complete healing of the root osteotomy. According to the finite element software Ansys Workbench, Conditions, observed before and after radical resection of the stress distribution and size under different stress directions, and comparative analysis to understand the trend of stress changes. Results When the loading condition was the same, the maximal stress, maxillary displacement and maximal displacement of the cervical and cervical parts as compared with the intact teeth increased when the root was cut off immediately. When the root tip bone tissue healed completely, Improvement, but still higher than the intact state of the teeth. When all the conditions are the same, the bigger the angle between the load direction and the long axis of the tooth is, the greater the overall stress level is. The larger the stress concentration area is, the larger the overall displacement value is. Conclusion The biomechanical stability of the intact teeth decreased before the root apical alveolar bone healed completely after the radical resection. After complete healing, the stability has been somewhat improved. Therefore, apical bone regeneration is related to the success or failure of radical surgery is to maintain the mechanical stability of the key teeth. Occlusal status of the tooth to withstand the level of force, the greater the increase of stress after radical resection, the choice of radical mastectomy as a treatment plan to consider occlusal morphology to consider factors to avoid stress concentration, loosening and other adverse consequences.