Abstract:

Abstract：Objective To compare the stress distribution on bone tissue around the implant denture with different crown-root ratio in repairing the first molar of mandibular. Methods Taking Dentium planting system with platform transfer structure of Korea as a reference，draw 5 groups of three-dimensional model which contains the corresponding base station，the central screw and porcelain crown with different crown-root ratio（1∶1.5，1∶1，1.5∶1，2∶1，3∶1）through 3D mapping software of PRO / E Wildfire 5.0. Take vertical and oblique loading on each model. Ansys Workbench13.0 was used to compare Von Mises stress distribution and the trend of stress changes of each model. Results With the vertical load，in any model with different crown-root ratio，the stress concentration appear in the neck，base stations，the central screw and crown of the plant，which are uniform in the overall stress distribution and few significant changes appeared in the Von Mises stress peak of the implant. With the oblique load，the maximum value of Von Mises stress increased significantly in each model，especially in the lip and cheek side of the neck of the plant，cortical bone，base stations，the central screw and crown. With the crown-root ratio increasing，the peak stress of each parts increased significantly. Conclusion The platform conversion effectively transfers the concentration area of stress in the interface between implant and bone，and reduces the absorption of alveolar bone，but it increases risk of loose and broken base stations and central screw.

Key words: implant-borne denture, three-dimensional finite element analysis, crown-root ratio, the first molar of mandibular

摘要：

目的 比较不同冠根比种植义齿修复下颌第一磨牙对种植修复体各部件及周围骨组织应力分布的影响。方法 本研究于 2012年9—12月在东北大学机械工程与自动化学院完成。参照具有平台转移结构的韩国Dentium种植系统，在PRO/E Wildfire 5.0三维制图软件中绘制冠根比分别为1∶1.5 、1∶1 、1.5∶1 、2∶1 、3∶1的5组包含相应基台、中央螺丝和烤瓷冠的种植修复体三维实体模型，进行垂直向及斜向加载，运用Ansys Workbench13.0比较各模型受力后Von Mises应力分布情况及应力变化趋势。结果 垂直载荷下，各模型整体应力分布较为均匀，在种植体颈部、基台、中央螺丝和牙冠均出现应力集中现象，不同冠根比的种植修复体Von Mises应力峰值变化不明显。斜向加载下，各模型最大Von Mises应力值明显增大，尤其种植体的唇颊侧颈部、皮质骨、基台、中央螺丝和牙冠的应力峰值增长明显，随着冠根比的增大各部分应力峰值明显增大。结论 平台转换有效转移种植体-骨界面应力集中区，减少牙槽骨的吸收，但增大了基台及中央螺丝松动和折断的风险。

关键词: 种植义齿, 三维有限元, 冠根比, 下颌第一磨牙