目的建立包含螺纹种植体的下颌骨三维有限元模型,分析不同直径种植体对即刻负载种植体骨界面应力、应变的影响。方法采用CT扫描和自主开发的USIS软件建立不同直径螺纹种植体即刻负载的三维有限元模型,用ANSYS软件分析直径为3.3、4.1、4.8mm的种植体,在垂直和颊舌向45o加载150N力时种植体骨界面的von Mises应力、应变值。结果垂直加载时,种植体骨界面的应力集中于颈部,应变集中于底部颊侧;三种直径种植体骨界面颈部的vonMises应力最大值分别为25、17.6、11.6MPa,应变最大值分别为1853、1303、1293με。颊舌向加载时,种植体骨界面的von Mises应力、应变值均明显增大,均主要集中于颈部舌侧;三种直径种植体骨界面颈部的von Mises应力最大值分别为131.1、78.7、68.1MPa,应变最大值分别为9622、5892和5816με。结论随直径的增大,种植体骨界面的应力、应变都呈下降趋势,以直径从3.3mm增大到4.1mm最为显著。认为采用即刻负载技术的螺纹种植体大小至少要4.1mm×10mm以上,而且要尽量避免受到非轴向力。

Objective To establish a three-dimensional finite element model of mandible with dental implants for immediate loading, and to analyze stress distribution in the bone around the dental implants with different implant diameter. Methods Three-dimensional finite element model of thread dental implants with immediate loading were constructed using CT scanning and USIS (Universal Surgical Integration System)software developed by ourselves, which including different diameter implants for 3.3 mm、 4.1 mm、 4.8 mm, respectively. The value of Von Mises stress、 strain of implant-bone interface were obtained and analyzed with ANSYS, when the dental implants were loaded with vertical、 buccolingual force of 150 N. Results When loaded with vertical force, the Von Mises stress concentration appeared on the neck of implants, and Von Mises strain were concentrated on the buccal side of the bottom of implants; the peak value of Von Mises stress on the neck of implant in the implant-bone interface for the above three different diameters were 25 Mpa、 17.6 Mpa、 11.6 Mpa and the strain of them were 1 853 με、1 303 με、1 293 με, respectively. When loaded with buccolingual force, the values of both Von Mises stress and strain increased apparently and the concentrations all appeared around the lingual side on the neck of implants , the corresponding peak values for the above three different diameters were 131.1 Mpa、 78.7 Mpa、 68.1 Mpa and the strain of them were 9 622 με、5 892 με、5 816 με,respectively. Conclusion With the addition of the dental implants diameter , the stress and strain on the bone around implants all decreased and it was remarkable especially when the diameter increased from 3.3 mm to 4.1 mm. It shows that the dimension of dental implants with immediate loading would at least be 10 mm×1 4.1 mm, and should avoid load with un-axial strength as possible as it can.

浙江省医学科技发展基金资助项目(2004B155); 温州市科技计划项目(Y2005A044)