Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA.
Dent Mater. 2011 Oct;27(10):964-71. doi: 10.1016/j.dental.2011.06.002. Epub 2011 Jul 12.
This study aims to assess the viability of using the acoustic emission (AE) measurement technique to detect and monitor in situ the interfacial debonding in resin composite restorations due to build-up of shrinkage stresses during polymerization of the composite.
The non-destructive testing technique that measures acoustic emission (AE) was used to detect and monitor the interfacial debonding in resin composite during curing of the composite. Four groups of specimens, n=4 each, were tested: (1) intact human molars with Class-I cavities restored with the composite Z100 (3M ESPE, USA); (2) intact human molars with Class-I cavities restored with the composite Filtek™ P90 (3M ESPE, USA); (3) ring samples prepared from the root of a single bovine tooth and 'restored' with Z100; (4) freestanding pea-size specimens of Z100 directly placed on the AE sensor. The restorations in Groups (1)-(3) were bonded to the tooth tissues with the adhesive Adper™ Scotchbond™ SE Self-Etch (3M ESPE, USA). The composites in all the specimens were cured with a blue light (3M ESPE, USA) for 40s. The AE signals were recorded continuously for 10 min from the start of curing. Non-destructive 3D imaging was performed using X-ray micro-computed tomography (micro-CT) to examine the bonding condition at the tooth-restoration interface.
The development of AE events followed roughly that of the shrinkage stress, which was determined separately by the cantilever beam method. The number of AE events in the real human tooth samples was more than that in the ring samples, and no AE events were detected in the pea-size specimens placed directly on the AE sensor. The number of AE events recorded in the specimens restored using Z100 was more than that found in specimens restored with Filtek P90. The micro-CT imaging results showed clear interfacial debondings in the tooth specimens restored with Z100 after curing, but no clear debonding was found in the P90 specimens.
The AE technique is an effective tool for detecting and monitoring in situ the interfacial debonding of composite restorations during curing. It can potentially be employed to evaluate the development of shrinkage stress and the quality of interfacial bonds in teeth restored with different composite materials, cavity geometries, and restorative techniques.
本研究旨在评估使用声发射（AE）测量技术检测和监测树脂复合材料修复体中界面脱粘的可行性，该技术可在复合材料聚合过程中因收缩应力而产生界面脱粘。
使用测量声发射（AE）的无损检测技术来检测和监测复合树脂在固化过程中的界面脱粘。测试了四组样本，每组 4 个样本：（1）用复合材料 Z100（3M ESPE，美国）修复的具有 I 类腔的完整人磨牙；（2）用复合材料 Filtek™ P90（3M ESPE，美国）修复的具有 I 类腔的完整人磨牙；（3）从单个牛牙根部制备的环样本并用 Z100“修复”；（4）直接放置在 AE 传感器上的豌豆大小的 Z100 独立样本。组（1）-（3）中的修复体通过粘合剂 Adper™ Scotchbond™ SE 自酸蚀（3M ESPE，美国）与牙组织结合。所有样本中的复合材料均用蓝光（3M ESPE，美国）固化 40s。从固化开始，连续记录 10min 的 AE 信号。使用 X 射线微计算机断层扫描（micro-CT）进行无损 3D 成像，以检查牙修复界面的粘结状态。
AE 事件的发展大致与收缩应力的发展一致，收缩应力是通过悬臂梁法单独确定的。在真实人牙样本中记录的 AE 事件数量多于环样本中的数量，而直接放置在 AE 传感器上的豌豆大小的样本中则未检测到 AE 事件。使用 Z100 修复的样本中记录的 AE 事件数量多于使用 Filtek P90 修复的样本。micro-CT 成像结果显示，固化后用 Z100 修复的牙样本中存在明显的界面脱粘，但在 P90 样本中未发现明显的脱粘。
AE 技术是一种有效检测和监测复合材料修复体在固化过程中界面脱粘的原位的工具。它有可能被用于评估不同复合材料、腔几何形状和修复技术修复的牙齿中收缩应力的发展和界面结合的质量。
