Design Optimization of Reduced-Diameter Implants in Simulated and Cadaver Bone

项目摘要 直径减小的牙种植体的外径小于3.75 mm。 颈部直径较小的牙齿，特别是在前部位置。在前部， 牙槽嵴通常不足以放置标准直径的种植体，因此直径减小的种植体可以避免 需要进行骨增强手术，从而避免额外的费用和植入前六个月的等待 安置然而，直径减小的植入物遭受更大的机械损伤发生率。 与标准直径种植体相比，这些并发症包括松动和/或 种植体-基台连接器螺钉断裂。幸运的是，我们的初步数据表明， 可以优化直径减小的植入物中的植入物-基台连接以增加它们的寿命。 我们以前进行了一个为期五年的项目，更有效的方法来评估机械可靠性 通过（1）验证使用有限元进行的种植体寿命预测的准确性 应力分析结合疲劳后处理软件;（2）验证加速寿命 使用过应力加速度和使用率的组合进行的物理试样试验 加速度我们实现了这些目标，这为我们提供了一套强有力的工具， 直径减小的牙种植体的设计优化。 在目前提出的项目中，我们将使用有限元建模来筛选25个种植体设计参数 以确定哪些参数应作为实验因素的设计优化减少- 直径的牙科植入物。候选参数通过四种类型的减少- 直径牙科种植体和测试设计参数与疲劳寿命的显着关联。第二、 我们将确定与最大预测值相对应的设计参数的最佳组合 减小直径的牙种植体的疲劳寿命。我们将使用人工神经网络， 使用我们的有限元分析结果进行培训，以执行设计优化， 响应面法（Response Surface Methodology）第三，我们将使用加速的 物理样本的寿命测试（ALT），以比较我们优化的植入物与 市售的模拟骨基准。第四，我们还将测试我们的优化原型， 尸体骨，以验证我们的新型模拟骨保持器材料，用于未来的植入物疲劳研究。

Project Summary Reduced-diameter dental implants have an outer diameter less than 3.75 mm. They are useful for replacing teeth that have small cervical diameters, especially in anterior locations. In the anterior, the width of the alveolar ridge is often insufficient to place a standard-diameter implant, so reduced-diameter implants avoid the need for bone augmentation surgery and thus avoid the additional cost and six-month wait prior to implant placement. However, reduced-diameter implants suffer from a much greater incidence of mechanical complications compared with standard-diameter implants. These complications include loosening and/or fracture of the implant-abutment connector screw. Fortunately, our preliminary data suggest that the design of the implant-abutment connection in reduced-diameter implants can be optimized to increase their lifetime. We previously conducted a five-year project on more efficient methods of evaluating the mechanical reliability of dental implants by (1) validating the accuracy of implant lifetime prediction performed using finite element stress analysis combined with fatigue post-processing software and (2) validating the accelerated lifetime testing of physical specimens performed using a combination of overstress acceleration and usage rate acceleration. We accomplished those aims, which provided us with a powerful set of tools for addressing the design optimization of reduced-diameter dental implants. In the currently proposed project, we will use finite element modeling to screen 25 implant design parameters to determine which parameters should be used as experimental factors in design optimization of reduced- diameter dental implants. The candidate parameters were identified by fatigue testing of four types of reduced- diameter dental implants and testing design parameters for significant association with fatigue lifetime. Second, we will identify the optimal combination of design parameters that corresponds to the maximum predicted fatigue lifetime for reduced-diameter dental implants. We will use Artificial Neural Networks that have been trained using the results of our finite element analyses to perform design optimization and will compare that method with Response Surface Methodology. Third, we will validate the virtual models by using accelerated lifetime testing (ALT) of physical specimens to compare the performance of our optimized implant with a commercially available benchmark in simulated bone. Fourth, we will also test our optimized prototype in cadaver bone to validate our novel simulated bone holder material for future implant fatigue studies.