Objective

To assess the influence of implant thread shape and inclination on the mechanical behaviour of bone-implant systems. The study assesses which factors influence the initial and full osseointegration stages.

Methods

Point clouds of the original implant were created using a non-contact reverse engineering technique. A 3D tessellated surface was created using Geomagic Studio^® software. From cross-section curves, generated by intersecting the tessellated model and cutting-planes, a 3D parametric CAD model was created using SolidWorks^® 2017. By the permutation of three thread shapes (rectangular, 30° trapezoidal, 45° trapezoidal) and three thread inclinations (0°, 3° or 6°), nine geometric configurations were obtained. Two different osseointegration stages were analysed: the initial osseointegration and a full osseointegration. In total, 18 different FE models were analysed and two load conditions were applied to each model. The mechanical behaviour of the models was analysed by Finite Element (FE) Analysis using ANSYS^® v. 17.0. Static linear analyses were also carried out.

Results

ANOVA was used to assess the influence of each factor. Models with a rectangular thread and 6° inclination provided the best results and reduced displacement in the initial osseointegration stages up to 4.58%. This configuration also reduced equivalent VM stress peaks up to 54%. The same effect was confirmed for the full osseointegration stage, where 6° inclination reduced stress peaks by up to 62%.

Significance

The FE analysis confirmed the beneficial effect of thread inclination, reducing the displacement in immediate post-operative conditions and equivalent VM stress peaks. Thread shape does not significantly influence the mechanical behaviour of bone-implant systems but contributes to reducing stress peaks in the trabecular bone in both the initial and full osseointegration stages.

中文翻译：

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螺纹形状和倾斜度对高原植入物系统生物力学行为的影响

客观的

评估植入物螺纹形状和倾斜度对骨植入物系统机械性能的影响。该研究评估了哪些因素会影响骨整合的初始阶段和完整阶段。

方法

原始植入物的点云是使用非接触式逆向工程技术创建的。三维镶嵌表面使用的Geomagic Studio创建^®软件。从横截面的曲线，由交叉的棋盘格状模型和切割平面产生一个3D参数CAD模型使用SolidWorks创建^®2017.通过排列三个螺纹形状（矩形，30°梯形，45°梯形）和三个螺纹倾角（0°，3°或6°）进行排列，获得了九种几何形状。分析了两个不同的骨整合阶段：初始骨整合和完全骨整合。总共分析了18种不同的有限元模型，并对每种模型应用了两种载荷条件。该模型的力学行为进行了有限元（FE）分析利用ANSYS分析^®诉17.0。还进行了静态线性分析。

结果

方差分析用于评估每个因素的影响。具有矩形螺纹和6°倾斜度的模型在最初的骨整合阶段提供了最佳结果，并减少了位移，最高可达到4.58％。这种配置还使等效VM应力峰值降低了54％。在整个骨整合阶段，也证实了相同的效果，其中6°的倾斜度将应力峰值降低了多达62％。

意义

有限元分析证实了螺纹倾斜的有益效果，减少了术后即时情况下的位移和等效的VM应力峰值。螺纹形状不会显着影响骨植入物系统的机械行为，但会有助于在初始和完整骨整合阶段减少小梁骨中的应力峰值。