Department of Biomedical Engineering, National Yang-Ming University, No. 155 Sec. 2 Linong Street, Taipei, Taiwan.
Dent Mater. 2013 Apr;29(4):382-8. doi: 10.1016/j.dental.2012.12.003. Epub 2013 Jan 18.
CAD/CAM ceramic restorative material is routinely bonded to tooth substrates using adhesive cement. This study investigates micro-crack growth and damage in the ceramic/dentin adhesive interface under fatigue shear testing monitored using the acoustic emission (AE) technique with optical coherence tomography (OCT).
Ceramic/dentin adhesive samples were prepared to measure the shear bond strength (SBS) under static load. Fatigue shear testing was performed using a modified ISO14801 method. Loads in the fatigue tests were applied at 80%, 70%, and 60% of the SBS to monitor interface debonding. The AE technique was used to detect micro-crack signals in static and fatigue shear bond tests.
The results showed that the average SBS value in the static tests was 10.61±2.23MPa (mean±standard deviation). The average number of fatigue cycles in which ceramic/dentin interface damage was detected in 80%, 70% and 60% of the SBS were 152, 1962 and 9646, respectively. The acoustic behavior varied according to the applied load level. Events were emitted during 60% and 70% fatigue tests. A good correlation was observed between crack location in OCT images and the number of AE signal hits.
The AE technique and OCT images employed in this study could potentially be used as a pre-clinical assessment tool to determine the integrity of cemented load bearing restored ceramic material. Sustainable cyclic load stresses in ceramic/dentin-bonded specimens were substantially lower than the measured SBS. Predicted S-N curve showed that the maximum endured load was 4.18MPa passing 10(6) fatigue cyclic.
CAD/CAM 陶瓷修复材料通常通过粘接剂与牙本质基底结合。本研究通过声发射（AE）技术结合光学相干断层扫描（OCT）监测疲劳剪切试验中陶瓷/牙本质粘接界面的微裂纹扩展和损伤。
制备陶瓷/牙本质粘接样本以测量静态载荷下的剪切结合强度（SBS）。采用改良的 ISO14801 方法进行疲劳剪切试验。疲劳试验中的载荷以 SBS 的 80%、70%和 60%施加，以监测界面脱粘。采用 AE 技术检测静态和疲劳剪切粘接试验中的微裂纹信号。
结果表明，静态试验中平均 SBS 值为 10.61±2.23MPa（平均值±标准差）。在 SBS 的 80%、70%和 60%下检测到陶瓷/牙本质界面损伤的平均疲劳循环数分别为 152、1962 和 9646。声发射行为根据施加的载荷水平而变化。在 60%和 70%的疲劳试验中发出了事件。OCT 图像中的裂纹位置与 AE 信号命中数之间观察到良好的相关性。
本研究中采用的 AE 技术和 OCT 图像可能可作为临床前评估工具，用于确定粘结承载修复陶瓷材料的完整性。陶瓷/牙本质粘结标本中可持续循环的载荷应力远低于测量的 SBS。预测的 S-N 曲线表明，最大承受载荷为 4.18MPa，通过 10(6)疲劳循环。
