有限元分析不同骨质下种植体长度及直径对初期稳定性的影响

Finite element analysis on the effect of implant length and diameter on initial stability under different bone conditions

背景:目前还没有就骨质、种植体直径与长度对初期稳定性影响的综合研究。目的:以载荷下种植体-骨界面的微动大小作为种植体初期稳定性的评价指标,探究骨质、种植体长度与直径对种植体初期稳定性的影响。方法:依据Zarb和Lekholm提出的骨质分类方法,建立Ⅰ,Ⅱ,Ⅲ,IV类骨质的下颌骨模型。参照士卓曼种植体参数,建立不同直径与长度的种植体模型,种植体直径分别为3.3,4.1,4.8 mm;长度分别为6,8,10,12 mm。应用有限元方法,对模型加载两种载荷(100,250N),进行垂直和倾斜方向加载。分析比较各组模型中种植体-骨界面的微动分布情况。研究方案的实施符合《赫尔辛基宣言》和大连大学机械工程学院的相关伦理要求,受试者对影像资料采集及用途完全知情同意并签署了"知情同意书"。结果与结论:(1)垂直加载下,颌骨骨质较好时种植体-骨界面的微动峰值出现在皮质骨区,颌骨骨质较差时种植体-骨界面的微动峰值出现在松质骨区;倾斜加载下,4类骨质下颌骨中种植体-骨界面产生的微动峰值都在皮质骨区;(2)在4种加载方式下,种植体的初期稳定性都随骨质的减弱而降低,随种植体直径与长度的增加而升高,且种植体直径对种植体初期稳定性的影响比长度大。

BACKGROUND:At present,there is no comprehensive study on the influence of bone quality,implant diameter,and length on initial stability.OBJECTIVE:The micromotion size of the implant-bone interface under load was used as the initial stability evaluation index to study the influence of bone quality,implant length,and diameter on the initial stability.METHODS:Mandibular models of bone types I,II,III,and IV were established,according to the bone classification method proposed by Zarb and Lekholm.Implant models with different diameters and lengths were established,referring to Straumann implant parameters.The implant diameters were 3.3,4.1,and 4.8 mm;the lengths were 6,8,10,and 12 mm.Using the finite element method,the model was loaded with two typical chewing loads(100,250 N),and the micromotion distribution of the implant-bone interface in each group of models was analyzed and compared under the two loads.The research plan was conducted in accordance with the Declaration of Helsinki and the relevant ethical requirements of the School of Mechanical Engineering,Dalian University.The subjects had fully informed consent and signed the"Informed Consent"for the collection of image data.RESULTS AND CONCLUSION:(1)The peak of the micromotion of the implant-bone interface appeared in the cortical bone area when the better bone jaws were loaded with a vertical load.The peak of the micromotion of the implant-bone interface appeared in the cancellous bone area when the poor bone jaws were loaded with a vertical load.Under oblique loading,the peaks of micromotion generated by the implant-bone interface in the four types of bone mandibles were all in the cortical bone area.(2)In the four loading modes,the initial stability of the implant decreased with the weakening of bone.The initial stability of the implant increased with the increase of the diameter and length of the implant;and the diameter of the implant had an effect on the initial stability of the implant and its influence was greater than that of the length.