【作者】 李翠；

【导师】 郭新程；

【作者基本信息】 中南大学 ， 口腔临床医学， 2008， 硕士

【摘要】 目的:通过建立部分下颌骨三维有限元模型,采用三维有限元分析法分析四种不同骨质中第一、第二磨牙缺失植体修复后,种植体—骨界面的应力分布及种植体的位移情况,研究不同骨质中单冠及联冠修复时种植体的生物力学特性,为不同骨质磨牙缺失的种植修复提供理论参考依据。方法:采用三维有限元分析法,建立12个含双种植体的下颌骨三维有限元模型。在第一、第二磨牙区各植入一种植体(4.0×13mm光滑圆柱形或4.8×10mm螺纹圆柱形种植体),分别垂直分散加载100N及颊舌向倾斜45°分散加载45N模拟牙合力加载,分析种植体—骨界面的Von-mises应力及种植体长轴的位移分布情况。结果:1、垂直及斜向加载时各修复方式的种植体—骨界面应力分布特点相同,均为从种植体颈部至根部逐渐减小,应力主要集中在颈部皮质骨区。同种骨质中不同修复方式,最大Von-mises应力值b＞a+b＞a,同种修复方式不同骨质,最大Von-mises应力值Ⅳ＞Ⅲ＞Ⅱ＞Ⅰ。各修复方式的最大Von-mises应力值均在骨组织所承受的生理限度范围之内。2、垂直及斜向加载时种植体长轴最大位移发生在皮质骨区。垂直加载时位移分布特点均为从种植体颈部至根部逐渐减小;斜向加载时在Ⅰ、Ⅱ、Ⅲ类骨质中位移均为从种植体颈部至根部逐渐减小,在Ⅳ类骨质中先减小,再增加;相同修复方式不同骨质时,加载后,种植体长轴产生的最大位移值Ⅳ＞Ⅲ＞Ⅱ＞Ⅰ,Ⅰ、Ⅱ类骨质的最大位移值均小于3um,Ⅲ类骨质a、a+b的最大位移值大于3um,b方式最大位移值小于3um。3、斜向加载时种植体—骨界面最大Von-mises应力值及种植体最大位移值均高于垂直向加载时。4、同种骨质中不同修复方式时,修复方式所产生的最大位移值a＞a+b＞b。结论:1、Ⅲ、Ⅳ类骨质磨牙缺失,在选择种植修复时宜慎重。2、从位移角度考虑:在Ⅰ、Ⅱ、Ⅲ类骨质磨牙缺失种植修复时以b单冠修复方式最优。更多还原

【Abstract】 Objective:Three dimension finite element models were built to study the stress distribution on implant-bone interface and the deviation of displacement of implant in bone with different cortical bone thicken, and investigate the biomechanical properties of implants with different bone density in uncoupled and splinted crown,thus to provide reference for molar restoration in clinics.Materials and Methods:This study built simplified twelve different mandible models.Three-dimension finite element analysis method was used.Two dental implants in the shape of cylinder(4.0×13mm)and/or thread(4.8×10mm)were implanted into the mandibular bone at the position of the first molar and the second molar with differrent cortical bone thickenss.A force load of 100N vertically and a force load of 45N under 45°lingually inclined to occlusal were applied respectedly to study the stress distribution on implant-bone interface and the deviation of displacement of implant.Results:(1)Whether axial loading or oblique loading,both the stress distribution characteristics of implant-bone interfaces of two implant systems were that the stress value was gradually diminished from the implant cervix to the root tip,and the peak Von-Mises stress district of the bone was concentrated on the implant neck.The maximum stress values of various repair modes were all within the normal physiological limits. Maximum Von-mises stress values b＞a+b＞a when different repair modes were used in the same bone.Maximum Von-mises stress valuesⅣ＞Ⅲ＞Ⅱ＞Ⅰwhen the same repair mode was used under different bone density.(2)Whether axial loading or oblique loading,the max-value of displacement of the implant long axis occurred at cortical bone.When the force was loaded vertically,the values of displacement were characterized by diminishing from the implant cervix to the root tip gradually.When the force was loaded obliquely,the same characteristic was observed in the bone of typeⅠ,Ⅱ,Ⅲ,but in the bone of typeⅣ,the values of displacement were increased before diminished.The max-value of displacement after force loaded wasⅣ＞Ⅲ＞Ⅱ＞Ⅰwhen the same repair mode was used under different bone density.The max-values of displacement in the bone of typeⅠ、Ⅱwere all less than 3um.In the bone of typeⅢ,The max-values of displacement by a and a+b were more than 3um,the max-values of displacement were less than 3um by using mode b.(3)When the force was loaded obliquely,Maximum Von-mises stress values on implant-bone interface and the max-values of displacement were both higher compared with loaded vertically.(4)When different repair modes were used in homologous bone,the max-values of displacement by different repair modes were manifested as a＞a+b＞b.Conclusion:1.More attention should be paid to implant restoration when the molar loss occurs in the bone of typeⅢandⅣ.2.Mode uncoupled b is the optimal choice for molar restoration when the molar loss occurs in the bone of typeⅠ,ⅡandⅢ,according to the displacement of the implant.更多还原