Kim Won Hyeon, Song Eun Sung, Ju Kyung Won, Lim Dohyung, Han Dong-Wook, Jung Tae-Gon, Jeong Yong-Hoon, Lee Jong-Ho, Kim Bongju
Clinical Translational Research Center for Dental Science, Seoul National University Dental Hospital, Seoul 03080, Korea.
Department of Mechanical Engineering, Sejong University, Seoul 05006, Korea.
Materials (Basel). 2020 Mar 27;13(7):1545. doi: 10.3390/ma13071545.
Mechanical testing based on ISO 14801 standard is generally used to evaluate the performance of the dental implant system according to material and design changes. However, the test method is difficult to reflect on the clinical environment because the ISO 14801 standard does not take into account the various loads from different directions during chewing motion. In addition, the fracture pattern of the implant system can occur both in the horizontal and the vertical directions. Therefore, the purpose of this study was to compare fatigue characteristics and fracture patterns between single directional loading conditions based on the ISO 14801 standard and multi-directional loading condition. Firstly, the static test was performed on five specimens to derive the fatigue load, and the fatigue load was chosen as 40% of the maximum load measured in the static test. Subsequently, the fatigue test was performed considering the single axial/occlusal (AO), AO with facial/lingual (AOFL) and AO with mesial/distal (AOMD) directions, and five specimens were used for each fatigue loading modes. In order to analyze the fatigue characteristics, the fatigue cycle at the time of specimen fracture and displacement change of the specimen every 500 cycles were measured. Field emission scanning electron microscopy (FE-SEM) was used to analyze the fracture patterns and the fracture surface. Compared to the AO group, the fatigue cycle of the AOFL and AOMD groups showed lower about five times, while the displacement gradually increased with every 500 cycles. From FE-SEM results, there were no different surface morphology characteristics among three groups. However, the AOMD group showed a vertical slip band. Therefore, our results suggest that the multi-directional loading mode under the worst-case environment can reproduce the vertical fracture pattern in the clinical situation and may be essential to reflect on the dental implant design including connection types and surface treatments.
基于ISO 14801标准的机械测试通常用于根据材料和设计变化来评估牙种植体系统的性能。然而，该测试方法难以反映临床环境，因为ISO 14801标准未考虑咀嚼运动期间来自不同方向的各种载荷。此外，种植体系统的骨折模式可在水平和垂直方向上发生。因此，本研究的目的是比较基于ISO 14801标准的单向加载条件和多向加载条件之间的疲劳特性和骨折模式。首先，对五个标本进行静态测试以得出疲劳载荷，并且选择疲劳载荷为静态测试中测得的最大载荷的40％。随后，考虑单轴向/咬合（AO）、AO加面部/舌侧（AOFL）和AO加近中/远中（AOMD）方向进行疲劳测试，并且每种疲劳加载模式使用五个标本。为了分析疲劳特性，测量了标本断裂时的疲劳循环以及每500个循环标本的位移变化。使用场发射扫描电子显微镜（FE-SEM）分析骨折模式和骨折表面。与AO组相比，AOFL和AOMD组的疲劳循环显示降低了约五倍，而位移每500个循环逐渐增加。从FE-SEM结果来看，三组之间没有不同的表面形态特征。然而，AOMD组显示出垂直滑移带。因此，我们的结果表明，在最坏情况下环境下的多向加载模式可以在临床情况下再现垂直骨折模式，并且对于反映包括连接类型和表面处理在内的牙种植体设计可能是必不可少的。
