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目的:探讨动态加载时微种植体压低基牙后固定桥力学行为的改变,为临床压低基牙后再进行牙体预备提供理论依据。方法:采用螺旋CT扫描健康人上颌骨、牙及牙周支持组织的二维图像,通过Mimics10.01、Ansys13.0等图像合成、有限元分析软件建立基牙牙槽骨水平吸收10%,上颌后牙分别压低0、0.5、1.0、1.5、2.0 mm后双端固定桥修复的三维有限元分析模型,模拟在1个咀嚼周期0.875 s内连续性施加垂直向、斜向(颊向与舌向)载荷作用,比较压低基牙前、后修复体、牙、牙周膜及硬骨板的应力随时间的变化情况。结果:随着压低量增加,修复体、牙体应力发生一定改变,这一改变与修复体结构、牙体结构有很大关系。牙周膜及硬骨板面积增大,整体应力有所降低。在一个动态载荷周期内,随着时间的积累,牙、修复体、牙周膜、硬骨板的应力均逐渐增大,在斜向载荷作用下,应力达到峰值,卸载终期仍有少量的应力残余。结论:采用微种植体压低基牙后,降低了修复体、牙、牙周膜、硬骨板的应力。在1个咀嚼周期中,基牙及支持组织的应力具有时间依赖性,侧向力对其影响大于垂直向力,且1个咀嚼周期结束时,基牙及支持组织有应力残余。随着基牙压低量的增加,残余应力减少。
OBJECTIVE: To investigate the change of mechanical behavior of fixed bridges after micro-implants are compressed under dynamic loading, and provide a theoretical basis for the clinical preparation of dental implants. Methods: The spiral CT was used to scan the two-dimensional images of the maxillary, dental and periodontal tissues. The images of Mimics 10.01 and Ansys 13.0 were combined and analyzed by finite element analysis software. The maxillary posterior alveolar bone was 10% The three-dimensional finite element model of the double-ended fixed bridge repaired after 0, 0.5, 1.0, 1.5 and 2.0 mm respectively was simulated. The vertical and diagonal (cheek and lingual) The effect of stress was compared with that of the stress before and after abutment reduction, periodontal ligament and periodontal ligament. Results: With the increase of depression, the stress of dental prosthesis changed a certain extent. This change has a great relation with the structure of restorations and the structure of dental structures. Periodontal ligament and hard board area increased, the overall stress decreased. In a dynamic loading cycle, the stress of teeth, prosthesis, periodontal ligament and rigid plate gradually increases with the time accumulation. Under the oblique load, the stress reaches its peak, and there is still a small amount of stress at the end of unloading Residual. CONCLUSIONS: Using micro-implants to lower the abutments reduced stress on the prosthesis, teeth, periodontal ligament, and plate. In one chewing cycle, the stress of the abutments and supporting tissues was time-dependent, the lateral force exerted more influence on them than the vertical force, and there was residual stress in the abutments and supporting tissues at the end of one chewing period. As the abutment pressure decreases, the residual stress decreases.