Han Xue-Lian, Liu Zong-Wei, Li Yan-Tao
Dept. of Stomatology, Rizhao Hospital of Traditional Chinese Medicine in Shandong Province, Rizhao 276800, China.
Hua Xi Kou Qiang Yi Xue Za Zhi. 2011 Apr;29(2):121-4.
To analyze the stress distribution of bone around the dental implants with lateral immediate loading of different angles by three dimensional finite element.
An adult edentulous mandible was adopted for CT scanning. The CT image was imported to universal surgical integration system to establish a mandible three dimensional mesh model. The real shape of standard thread implant was simulated and the finite element model of mandible with dental implants for immediate loading was established. The models were immediately loaded with 150 N through the angle of 0 degrees, 10 degrees, 20 degrees, 30 degrees. The ANSYS 10.0 was used to analyze the Von Mises stress on the bone around dental implants.
The accurate finite element model of mandible with dental implants for immediate loading was successfully established. The three dimensional finite element analytical results showed: Under axial load, the Von Mises stress of bone contact surface concentrated on the cortical bone of the implant cervix. The strain distribution was even, and centralized at the cortical bone of the implant cervix, cancellous bone of implant bottom and thread contact area. Under different lateral angle load, the Von Mises stress of bone contact surface also concentrated on the cortical bone of the implant cervix, but the maximum value was 4 times of the vertical loading, the strain distributed unevenly, mainly concentrated on the cortical bone of the implant cervix. With the load angle increased, the stress and the strain value also increased.
When an axial force was immediately loaded, the stress value and the strain concentration value of bone interface around the dental implants are not apparently concentrated, the stress is distributed well. While a lateral force is loaded, the stress values and the strain concentration values of bone interface around the dental implants apparently increase and the strain are distributed unevenly.
采用三维有限元方法分析不同角度侧向即刻加载时牙种植体周围骨组织的应力分布。
选取成人无牙下颌骨进行CT扫描，将CT图像导入通用外科集成系统建立下颌骨三维网格模型，模拟标准螺纹种植体的真实形状，建立即刻加载牙种植体的下颌骨有限元模型。模型分别以0度、10度、20度、30度的角度即刻加载150 N力，应用ANSYS 10.0分析牙种植体周围骨组织的Von Mises应力。
成功建立了即刻加载牙种植体的下颌骨精确有限元模型。三维有限元分析结果显示：轴向加载时，骨接触面的Von Mises应力集中在种植体颈部皮质骨，应变分布均匀，集中在种植体颈部皮质骨、种植体底部松质骨及螺纹接触区域。不同侧向角度加载时，骨接触面的Von Mises应力也集中在种植体颈部皮质骨，但最大值是垂直加载时的4倍，应变分布不均匀，主要集中在种植体颈部皮质骨。随着加载角度增大，应力和应变值均增大。
轴向即刻加载时，牙种植体周围骨界面的应力值和应变集中值无明显集中，应力分布良好。侧向加载时，牙种植体周围骨界面的应力值和应变集中值明显增大，应变分布不均匀。
