不植骨上颌窦内提升术三维有限元模型建立及功能载荷下的应力分布

【目的】探讨利用三维有限元方法分析功能状态下，上颌后牙区不同种植模式种植体周围的应力分布及位移情况。【方法】调整上颌窦底的高低，形成上颌窦底部高度不一的2个上颌骨模型（即正常窦嵴距和低窦嵴距2种模型）；建立4种种植体有限元模型，分别为穿窦种植体：4．1mm×8．0mm及4．8mm×8．0mm；非穿窦种植体：4．1mm×10．0mm及4．8mm×10．0mm。根据种植体植入方式不同，将4种种植体模拟植入相应的上颌骨模型中，即不植骨上颌窦内提升植人组：（种植体）穿窦模型；种植体常规植人组：（种植体）非穿窦模型2种，并通过垂直加载200N力量和斜向45。加载100N力量模拟种植体的功能状态。【结果】经有限元计算及分析，在垂直力作用下，穿窦组种植体周围应力分布同非穿窦组无明显差别；在斜向力作用下，非穿窦组位移及应力集中情况与穿窦组差异较小。【结论】虽然不植骨上颌窦内提升植入组骨量少，但选用相对短且粗的种植体可以克服骨量不足带来的缺陷，能为种植体周围创造良好的成骨环境。

The three dimensional finite element analysis for stress distribution of maxilla with different implant model under functional loads

Objective ] To explore the stress distribution and displacement around different dental implant of the maxilla. Methods] Two three-dimensional finite element model of maxilla were built, one with normal vertical height of bone in the maxilla sinus floor and the other with poor vertical height of bone in the same area. Four dental implant models were built either, the size of the dental implants were 4.1 mm x 8.0 mm, 4.8 mm x 8.0 mm, 4.1 mm x 10.0 mm and 4.8 mm x 10.0 mm. The 4.1 mm x 8.0 mm and 4.8 mm x 8.0 mm implants were used in the model with poor vertical height of bone and the tip of that overstepped the maxilla sinus floor 2.5 mm. 200 N （Newton） force was applied vertically and 100 N force was applied obliquely （45 degree） on the dental implants to simulate the functional status. Results]No difference was observed between the two models of maxilla under vertical loads and little difference was observed between the two models of maxilla under oblique loads. Conclusion ] Dental implants with relatively shorter length and larger diameter are qualified for maxilla with poor vertical height of bone in maxilla sinus areas.