Sliding contact fatigue damage in layered ceramic structures
Sliding contact fatigue damage in layered ceramic structures
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DOI：
10.1177/154405910708601105
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发表时间：
2007-11-01
影响因子：
7.6
通讯作者：
Zhang, Y.
中科院分区：
文献类型：
--
作者：
Kim, J.-W.;Kim, J.-H.;Zhang, Y.
瓷器式的修复体经常因重复的咬合负荷而碎裂和断裂，从而使疲劳研究相关。大多数疲劳研究仅限于单轴载荷而无需滑动运动。我们假设与单轴载荷相比，双轴载荷（接触式载荷 - 滑移升级，模拟咀嚼周期）可以加速分层陶瓷的疲劳。将整体玻璃板粘合到聚碳酸酯底物上，作为牙本质上全陶瓷冠的透明模型。通过口腔运动模拟器设备，通过硬球在水中应用单轴和双轴循环接触。单轴（接触载荷升压）和传统的R-Ratio疲劳（缩进器从未离开样品表面）产生了相似的寿命，而双轴疲劳更为严重。双轴疲劳中加速的裂纹生长速率归因于移动凹痕器的后缘的拉伸应力增强。提供了用滑动球反复加载的脆性材料中损伤演变的断裂力学描述。临床相关性已解决。
Porcelain-veneered restorations often chip and fracture from repeated occlusal loading, making fatigue studies relevant. Most fatigue studies are limited to uni-axial loading without sliding motion. We hypothesized that bi- axial loading (contact-load-slide-liftoff, simulating a masticatory cycle), as compared with uni-axial loading, accelerates the fatigue of layered ceramics. Monolithic glass plates were epoxy-joined to polycarbonate substrates as a transparent model for an all- ceramic crown on dentin. Uni-and bi- axial cyclic contact was applied through a hard sphere in water, by means of a mouth- motion simulator apparatus. The uni- axial (contact-load-hold-liftoff) and traditional R-ratio fatigue (indenter never leaves the specimen surface) produced similar lifespans, while bi- axial fatigue was more severe. The accelerated crack growth rate in bi- axial fatigue is attributed to enhanced tensile stresses at the trailing edges of a moving indenter. Fracture mechanics descriptions for damage evolution in brittle materials loaded repeatedly with a sliding sphere are provided. Clinical relevance is addressed.