School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia.
J Mech Behav Biomed Mater. 2013 Apr;20:387-97. doi: 10.1016/j.jmbbm.2012.08.019. Epub 2012 Sep 1.
Rapid and stable osseointegration signifies a major concern in design of implantable prostheses, which stimulates continuous development of new implant materials and structures. This study aims to develop a graded configuration of a bead/particle coated porous surface for implants by exploring how its micromechanical features determine osseointegration through multiscale modeling and remodeling techniques. A typical dental implantation setting was exemplified for investigation by using the remodeling parameters determined from a systematic review of bone-implant-contact (BIC) ratio published in literature. The global responses of a macroscale model were obtained through 48 month remodeling simulation, which forms the basis for the 27 microscopic models created with different particle gradients ranging from 30 to 70μm. The osseointegration responses are evaluated in terms of the BIC ratio and the averaged 10% peak Tresca shear stress (PTS). Within the sampling designs considered, the configuration with 50-30-30μm particle sizes provides the best outcome, counting 20% more BIC ratio and 0.17MPa less PTS compared with the worst case scenario, also outperforming the best uniform morphology of 70μm particles. Furthermore, the response surface method (RSM) was utilized to formulate the bone remodeling responses in terms of gradient parameters across three layers. Gradient 30.0-30.0-32.1 is found an optimal gradient for BIC ratio, and 70-45.4-40.8 the best for the minimum PTS. The multiobjective optimization was finally performed to simultaneously maximize BIC ratio and minimize PTS for achieving the best possible overall outcome. Due to strong competition between these two design objectives, a Pareto front is generated. To make a proper trade-off, the minimum distance selection criterion is considered and the gradient of 37.1-70.0-67.7 appears an optimal solution. This study provides a novel surface configuration and design methodology for individual patient that allow optimizing topographical gradient for a desirable patient-specific biomechanical environment to promote osseointegration.
种植体骨整合的快速和稳定是种植体设计的主要关注点，这促使了新的种植体材料和结构的不断发展。本研究旨在通过探索微结构特征如何通过多尺度建模和重塑技术来确定骨整合，从而开发一种具有珠/颗粒涂层多孔表面的梯度构型的植入物。通过使用从文献中发表的骨-种植体接触（BIC）比率的系统评价中确定的重塑参数，对典型的牙科植入物设置进行了例证研究。通过 48 个月的重塑模拟获得了宏观模型的全局响应，这为创建具有 30 至 70μm 不同颗粒梯度的 27 个微观模型奠定了基础。通过 BIC 比率和平均 10％峰值 Tresca 剪切应力（PTS）评估骨整合响应。在所考虑的采样设计中，与最差情况相比，粒径为 50-30-30μm 的颗粒配置提供了最佳结果，其 BIC 比率增加了 20％，PTS 降低了 0.17MPa，也优于最佳的 70μm 颗粒均匀形态。此外，还利用响应面法（RSM）根据三个层的梯度参数来制定骨骼重塑响应。发现梯度 30.0-30.0-32.1 对于 BIC 比率是最佳梯度，而 70-45.4-40.8 对于最小 PTS 是最佳梯度。最后进行了多目标优化，以同时最大程度地提高 BIC 比率并最小化 PTS，从而实现最佳的整体效果。由于这两个设计目标之间存在激烈竞争，因此生成了 Pareto 前沿。为了进行适当的权衡，考虑了最小距离选择标准，并且梯度 37.1-70.0-67.7 似乎是最佳解决方案。本研究为个体患者提供了一种新的表面构型和设计方法，允许针对理想的患者特定生物力学环境优化地形梯度，以促进骨整合。
