【摘要】 背景：种植固定修复已成为患者满意度更高的修复方式，All-on-Four和翼上颌种植在一定条件下均可达到种植要求，目前缺少不同骨质条件下该两种方案生物力学层面的对比分析。目的：采用三维有限元方法比较All-on-Four和翼上颌种植方案在不同骨质下应力分布的差异，探讨适宜的种植方案。方法：选取一名上颌骨骨量严重不足无牙颌患者的锥形束CT数据，建立3种不同皮质骨厚度(1.0,1.5,2.0 mm)及2种不同松质骨密度(高密度、低密度)的实体化模型，每种模型分别设计All-on-Four和翼上颌种植2种方案，共计12组模型。对双侧后牙区各施加200 N垂直静力，计算出种植体、皮质骨的von Mises应力值和钛支架变形量。结果与结论：(1)两种种植方案下种植体及皮质骨应力最集中处均在最远端位点，钛支架变形最大处均在支架远端；(2)相同松质骨密度下，无论是All-on-Four还是翼上颌种植，种植体、皮质骨von Mises应力值及钛支架变形量均在皮质骨厚度1 mm时最大，随着皮质骨厚度的增加，种植体、皮质骨von Mises应力值及钛支架变形量减小；(3)相同种植方案下，低密度松质骨组种植体、皮质骨von Mises应力值及钛支架变形量均大于高密度松质骨组；(4)相同骨质条件下，翼上颌种植组种植体、皮质骨von Mises应力值及钛支架变形量均小于All-on-Four组(P <0.05)；(5)结果表明，皮质骨厚度和松质骨密度增加有利于减小种植体、皮质骨的应力集中和钛支架变形，从生物力学角度，翼上颌种植方案较All-on-Four更有利于种植固定修复的远期预后。更多还原

【Abstract】 BACKGROUND: Implant fixation has become a more satisfactory repair method for patients. All-on-Four and pterygomaxillary implants can meet the implant requirements under certain conditions. At present, there is no biomechanical comparative analysis of the two schemes under different bone quality conditions.OBJECTIVE: To explore the appropriate implant scheme, three-dimensional finite element analysis was used to compare the stress distribution of All-on-Four and pterygomaxillary implant under different bone conditions.METHODS: The cone beam CT data of an edentulous patient with severe maxillary bone deficiency were selected, in order to set up physical models with three kinds of cortical bone thickness(1.0, 1.5, 2.0 mm) and two cancellous bone densities(high density, low density). For each model, All-on-Four and pterygomaxillary implant schemes were designed respectively. A total of 12 models were established and 200 N vertical static forces were applied to the bilateral posterior teeth to calculate the von Mises stress values of implants and cortical bone, together with the deformation of titanium framework.RESULTS AND CONCLUSION:(1) The von Mises stress values of implants and cortical bone were at the most distal site and the deformation of titanium framework was at the distal end of the stent in All-on-Four and pterygomaxillary implant designs.(2) Under the same cancellous bone density, the von Mises stress values of implants and cortical bone and the deformation of titanium framework were the highest in 1 mm cortical bone, and decreased with the increase of cortical bone thickness in All-on-Four and pterygomaxillary implant designs.(3) Under the same implant design, the von Mises stress values of implant, cortical bone and the deformation of titanium framework were larger in low-density cancellous bone than those of high-density cancellous bone.(4)Under the condition of the same bone, the von Mises stress values of implant, cortical bone and titanium framework deformation in pterygomaxillary implant group were lower than those in All-on-Four group(P < 0.05).(5) The results showed that the increase of cortical bone thickness and cancellous bone density could reduce the stress concentration of implants and cortical bone and the deformation of titanium framework. From the perspective of biomechanics, the pterygomaxillary implant was more favorable for long-term prognosis than All-on-Four.更多还原