微型正畸支抗种植体即刻挤压植入时骨界面应力分析  

Stress distribution in press-fit orthodontic microimplant bone interface

作　　者：武建潮[1] 黄吉娜[1] 赵士芳[1] 徐学军[1] 

机构地区：[1]浙江大学口腔医学院正畸科,浙江杭州310006

出　　处：《上海口腔医学》2006年第6期619-622,共4页Shanghai Journal of Stomatology

基　　金：浙江省卫生厅科研基金(2005B104)

摘　　要：目的研究微型正畸支抗种植体即刻植入时骨界面应力大小及分布,为微型支抗种植体即刻加载提供参考。方法将局部下颌骨简化成一个等腰梯形,颌骨骨块长20mm,断面高为30mm,上边宽为10mm,底边宽14mm,皮质骨厚度设定为1.6mm;微型种植体直径设定为1.2mm,长6mm。利用ANSYS9.0软件,建立局部微型种植体-骨的三维有限元模型。下颌骨材料属性设定为线性、正交各向异性,种植体-骨界面定义为完全连接。将断端处、下颌骨局部骨块面及底面的所有节点给予刚性约束。模拟种植体即刻植入时的情况,将骨界面初始位移设定为0、0.05、0.1mm,分析各指定初始位移时骨界面应力大小及分布。结果即刻加载时,0mm初始位移下,种植体骨界面无应力分布;初始位移为0.05mm时,骨界面应力集中在骨皮质内,分布较均匀,衰减幅度很小,近远中方向上的VonMises应力为1648MPa,龈向为1782MPa。初始位移为0.1mm时,近远中方向上的VonMises应力为2012MPa,龈向为2110MPa。结论微型种植体挤压植入时会产生较大的初始应力,即刻加载时,应当考虑这种初始应力。PURPOSE： The goal of this study is to analyse the stress distribution in the press-fit microimplant-bone interface and its indications for immediate loading of orthodontic microimplant. METHODS： Three-dimensional finite element models were created of a 20mm section of posterior mandible simplified in isosceles trapezoid shape, 30mm in height, 10mm in upper side width, 14mm in lower side width, with a single microimplant, 1.2mm in diameter, 6mm in length embedded in the bone. The cortical bone thickness was assumed as 1.6mm. Cortical and cancellous bone were modeled as transversely isotropic and linearly elastic materials. Titanium was modeled as isotropic and linearly elastic material. Perfect bonding was assumed at microimplant - bone interfaces. ANSYS 9.0 finite element analysis software was used to generate the simplified finite element models of the local mandible-implant complex. 0mm, 0.05 mm and 0.1mm press-fit were arbitrarily set to the implant-bone interface to mimic the situation of immediate placement of microimplant. Stresses in the microimplant-bone interface were calculated under these ＂press-fit＂. RESULTS： Stresses distributed mainly in the cortical bone interface. At 0mm press-fit, the stress was 0 MPa. For 0.05mm press-fit, the stress was 1648 MPa in mesio-distal direction, 1782MPa in occluso-gingival direction;and for 0.1mm, it reached 2012MPa in mesio-distal direction, 2110MPa in occluso-gingival direction. As the ＂press-fit＂ increased, the stresses increased accordingly. CONCLUSION： Values of initial stress in the microimplant-bone interface due to press-fit generated by immediately placed microimplant were very high in these limited and simplified three dimensional finite element models. It reminded us that the initial stress be taken into consideration when immediate loading of the microimplant is planned. Supported by Research Fund of Health Bureau of Zhejiang Province （2005B104）.

关 键 词：正畸支抗 微型种植体 初始位移 应力 

分 类 号：R783[医药卫生—口腔医学]