翼上颌种植设计在上颌后牙区牙列缺损种植修复中的应力分析

Stress analysis of pterygomaxillary implant design in implant restoration of maxillary posterior partial edentulism

目的:应用三维有限元研究翼上颌种植设计在上颌后牙区牙列缺损种植修复中骨组织及种植体应力分布的变化。方法:在六组上颌后牙区牙列缺损的颌骨模型中,第二前磨牙位置植入一枚常规植体,避开上颌窦在翼上颌区域分别以咬合平面45°或以Frankfort平面70°倾斜植入一枚种植体,制作三单位种植桥修复体。以200 N的静态力垂直加载于后牙功能尖上,应用软件分析翼上颌种植体及周围骨组织的应力。结果:70°倾斜种植后,颌骨应力为(43.18±17.15)MPa;45°倾斜种植时,颌骨应力为(67.25±18.44)MPa。70°倾斜种植配合近中种植体形成固定桥联冠修复体,其跨度大于三单位,在第二磨牙加载垂直向力200 N后,颌骨应力为(32.49±19.01)MPa,最大应力位于倾斜植入的种植体穿出位点处;在第一磨牙加载垂直向力200 N后,颌骨应力为(26.89±14.66)MPa,最大应力位于近中种植体穿出位点处。45°倾斜种植配合近中种植体形成固定桥联冠修复体,其跨度约为三单位,在第二磨牙的颌骨应力为(39.88±17.12)MPa,最大应力位于倾斜植入的种植体穿出位点处;在第一磨牙的颌骨应力为(31.03±15.05)MPa,最大应力位于近中种植体穿出位点处。结论:翼上颌区种植体可70°倾斜植入时,上部修复体可选择单冠修复或固定桥联冠修复;种植体可45°倾斜植入时,上部修复体须选择固定桥联冠修复。

Objective:To study the stress distribution after pterygomaxillary implantation in posterior maxillary alveolar by using three⁃dimensional finite element method.Methods:In six models with dentition defects in the posterior maxillary region,tilted implants were placed at 45°toocclusal plane or at 70°to Frankfort plane and constructed fixed bridges with normal implants in the pre⁃molar maxillary region.The static force of 200 N was vertically loaded on the second molar or first molar of the fixed bridges to analyze the stress distribution in the posterior maxillary alveolar bone.Results:The stress of alveolar bone was(43.18±17.15)MPa after verti⁃cal force loading to 70°tilted implantation while it was(67.25±18.44)MPa in 45°tilted implantation.The stress of alveolar bone was about(32.49±19.01)MPa when vertical force loading to the second molar of fixed bridges constructed with the 70°tilted implant and normal implant while the stress was about(26.89±14.66)MPa when 200 N vertical force loading to the first molar of the fixed bridges.The stress of alveolar bone was about(39.88±17.12)MPa when 200 N vertical force loading to the second molar of fixed bridges constructed with the 70°tilted implant and normal implant while the stress was about(31.03±15.05)MPa when 200 N vertical force loading to the first molar of the fixed bridges.Conclusions:Both the single crown and fixed bridge could be used when the implant was im⁃planted in the pterygomaxillary region at an angle of 70°.But fixed bridge design needed to be used when the implant was implanted in the pterygomaxillary region at an angle of 45°.