牙种植体即刻负载骨界面应力分布的三维有限元分析

Three Dimensional Finite Element Analysis of the Stress Distribution of Dental Implants with Immediate Loading

目的:用三维有限元法分析牙种植体即刻负载骨界面的力学特性。方法:采用CT扫描和自主开发的USIS软件建立螺纹种植体即刻负载的三维有限元下颌骨模型,用ANSYS计算垂直加载、颊舌向45o及近远中向45o加载150N力时种植体骨界面的Von Mises应力、应变值。结果:垂直加载时骨界面的Von Mises应力集中于颈部舌侧骨皮质,应变分布均匀,以颈部骨皮质、底部颊侧骨松质及颊侧螺纹接触部位的松质骨较为集中;颊舌向加载时骨界面的Von Mises应力也集中于颈部舌侧骨皮质,但最大值是垂直加载时的4.15倍,应变分布不均匀,主要集中于颈部舌侧骨皮质,最大值是垂直加载时的3.98倍;近远中斜向加载时骨界面的Von Mises应力集中于颈部远中侧骨皮质,最大值是垂直加载时的3.72倍,应变集中于底部近中侧骨松质,最大值是垂直加载时的1.51倍。结论:即刻垂直加载时,种植体周围骨质应力及应变无明显集中,分布较均匀,颊舌向及近远中向加载时应力、应变明显增大,分布不均匀。

Objective ：To analyze the stress distribution of bone around the dental implants with immediate loading with the method of three-dimensional finite element. Methods ：Three-dimensional finite element model of thread dental implants with immediate loading was developed using CT scanning and USIS （Universal Surgical Integration System）software developed by ourselves. The value of Von Mises stress .strain of implant-bone interface were calculated with the software of ANSYS, when the dental implants were loaded with vertical, buccolingual and mesiodistal force of 150 N. Results：When the dental implants were loaded with vertical force, the Von Mises stress concentration appeared around the lingual cortical bone intergrated with the neck of implants, and Von Mises strain were well-distributed,. When the dental implants were loaded with buccolingual force, the Von Mises stress and strain concentration all appeared around the lingual cortical bone intergrated with the neck of implants, but the maximum value of Von Mises stress increased by 315%, the maximum value of strain increased by 298%, and the strain distribution weren＇ even. When the dental implants were loaded with mesiodistal force, the Von Mises stress concentration appeared around the distall cortical bone intergrated with the neck of implants, the maximum value of Von Mises stress increased by 272%, and Von Mises strain concentrated on on the mesial cancellous bone intergrated with the bottom of implants, the maximum value of Von Mises strain increased by 51%. Conclusion：Von Mises stress and strain didn＇t concentrated obviously and the distribution of them were even, when dental implants were loaded with immediate vertical force. However, when dental implants were loaded with immediate oblique force, the value of Von Mises stress and strain increased apparently and the distribution of them were quite uneven.