Objective:To evaluate the distribution of bone stress around the implant of different height of the crown connected angled abutment by finite element analysis,in order to provide a theoretical basis that design implant restoration program.Methods:CBCT was used to collect relevant data and images of the maxillary first molar area.Mimicsl0.0 was used to establish the model of maxillary first molar crown.The physical model of the maxillary first molar crown was finely treated with Geomagic 12.0 software.SolidWorks 12.0 software to design different height of the crown connected angled abutment of standard soft-tissue-level implants.The clinical crown-to-root ratio were designed to be 1 ∶ 1.5,1 ∶ 1,1.5 ∶ 1,2 ∶ 1,and 15°,20°,25°,30°.Ansys14.5 workbench was the models of finite element analysis.Results:1,under the vertical load,when the abutment angle is greater than 15°,the peak value of Von-Mises stress of cortical bone and cancellous bone tends to decrease with the increasing crown-root ratio.Special conditions are as follows:when the abutment angle is 10°,25°,the crown height is best to avoid l0mm;when the abutment angle is 10°,the crown height should be reduced.So the crown height should not be too large.Under the oblique load,when the angle of the abutment is the same,the stress peak of the bone around the implant increases with the height of the crown.When the height of the crown is the same,the bone stress around the implant is not increasing with the abutment angle is increased.When the crown height increased,compared to the stress,there were no significant difference,P＞ 0.05.2,Compared to different kinds of abutments,only 10° and 30° and 15° and 30° between the stress was statistically significant.Conclusion:Increasing the angle of the clinical abutment and changing the crown-to-root ratio within a certain range does not show an adverse effect on the implant.It is not applicable that the clinical crown-to-root ratio of natural teeth is simply applied to the implant and the bone surrounding the implant.The implantation of the implant can not consider the height of the crown and the angle of the abutment,but the maximum of the abutment angle does not exceed 30°.%目的:通过有限元分析不同临床冠根比连接不同角度基台时种植体周围骨质应力分布情况,为更好的设计种植修复方案提供理论依据.方法:使用CBCT对上颌第一磨牙区进行扫描收集相关数据和图像,利用Mimics10.0建立上颌第一磨牙牙冠的模型.使用geomagic 12.0软件进行精细处理获得上颌第一磨牙牙冠的实体模型.利用SolidWorks 12.0软件直接创建并模拟植入不同临床冠根比连接不同倾斜角度的基台.种植体模拟Straumann软组织水平标准种植体.修改临床冠根比,临床冠根比分别设计为1∶1.5、1∶1、1.5∶1、2∶1分别连接15°、20°、25°、30°4种角度基台共16组模型.使用Ansys14.5workbench有限元分析插件对模型进行应力分析.结果:垂直载荷下,当基台角度大于15°时,随着冠根比值越来越大,骨皮质与骨松质的Von-Mises应力峰值总体有减小趋势.特殊情况如下,基台角度为10°、25°时,冠高度最好避开10mm;基台角度为10°时,冠高度应减小,冠高度不宜过大.斜向载荷下,当基台的角度相同时,种植体周围骨质的应力峰值随冠高度的增大在增大.冠高度相同时,当基台角度在增加时,种植体周围的骨质应力不在增大.冠根比增加时,种植体周围的骨质应力之间数值相比,P＞0.05,没有统计学意义.角度基台只有在10°与30°和15°与30°之间对比时差异有统计学意义.结论:在一定范围内加大临床基台角度与改变冠根比并不会对种植体产生不利的作用力,所以将天然牙的临床冠根比理论简单的应用于种植体周围的骨质和种植体是不准确的.
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