监测不同 CAD/CAM 材料的疲劳损伤：一种新的基于光学相干断层扫描的方法。
Monitoring fatigue damage in different CAD/CAM materials: A new approach with optical coherence tomography.
机构信息
Justus Liebig University, Dental Clinic, Department of Prosthodontics, Schlangenzahl 14, 35392 Giessen, Germany.
出版信息
J Prosthodont Res. 2021 Feb 24;65(1):31-38. doi: 10.2186/jpr.JPOR_2019_466. Epub 2020 Oct 1.
PURPOSE
To investigate fatigue damage over time, monolithic posterior computer-aided-designed/computer-aided-manufactured (CAD/CAM) crowns were artificially aged in a mouth-motion-simulator, and damage was monitored with optical coherence tomography (OCT).
METHODS
Forty-eight crowns were milled of six different CAD/CAM-materials (n=8), including 3Y-TZP (Lava Plus,'3Y'), 4Y-PSZ (Pritidentamultidisc,'4Y'), 5Y-PSZ (Prettauanterior,'5Y'), zirconia-reinforced lithium silicate (CeltraDuo,'ZLS'), hybrid ceramic (Vita Enamic,'VE'),and resin composite (BrilliantCrios,'COM'), and were adhesively luted on CAD/CAM-milled human molars. Specimens were artificially aged in a mouth-motion-simulator (50-500N, 2Hz, 37°C) for a period of 1 million cycles. Before loading and every 250,000 cycles, the specimens were investigated with spectral domain (SD)-OCT (RS-3000). The maximum vertical and horizontal damage were measured with imaging-processing-software (ImageJ). After testing, the specimens were sliced and analysed via light microscope (Zeiss) to compare the new OCT method with the established light microscope method. Data were subjected to ANCOVA and 2x4-ANOVA.
RESULTS
No failure occurred during mouth-motion-simulation. However, all specimens (except for 3Y and 4Y) showed fatigue damage. There was a significant difference in the maximum damage between the CAD/CAM-materials (p<.05). ZLS exhibited the highest damage, followed by VE, COM and 5Y. While damage associated with 5Y was initially noticed after 750,000 cycles, all other materials already showed crack formation after 250,000 cycles. Furthermore, a linear increase in damage over time was noticed in all materials. Due to the shallow light penetration of OCT, damage in the outer area could only be visualized with light microscope.
CONCLUSIONS
OCT is feasible for monitoring fatigue damage over time within different CAD/CAM-materials, particularly for subsurface damages.
目的
为了研究随时间推移的疲劳损伤，采用口腔运动模拟器对整体式计算机辅助设计/计算机辅助制造（CAD/CAM）后牙冠进行人工老化，并通过光相干断层扫描（OCT）监测损伤。
方法
从六种不同 CAD/CAM 材料（n=8）中铣削出 48 个牙冠，包括 3Y-TZP（Lava Plus，'3Y'）、4Y-PSZ（Pritidenta multidiscc，'4Y'）、5Y-PSZ（Prettau anterior，'5Y'）、氧化锆增强锂硅玻璃陶瓷（Celtra Duo，'ZLS'）、混合陶瓷（Vita Enamic，'VE'）和树脂复合材料（BrilliantCrios，'COM'），然后将这些牙冠粘接到 CAD/CAM 铣削的人磨牙上。标本在口腔运动模拟器中（50-500N，2Hz，37°C）进行 100 万次循环的人工老化。在加载前和每 25 万次循环后，使用光谱域（SD）-OCT（RS-3000）对标本进行检测。用图像处理软件（ImageJ）测量最大垂直和水平损伤。测试后，通过光学显微镜（Zeiss）对标本进行切片分析，以比较新的 OCT 方法和已建立的光学显微镜方法。数据采用协方差分析和 2x4-方差分析。
结果
在口腔运动模拟过程中没有发生失效。然而，所有标本（3Y 和 4Y 除外）均显示出疲劳损伤。CAD/CAM 材料之间的最大损伤存在显著差异（p<.05）。ZLS 表现出最高的损伤，其次是 VE、COM 和 5Y。虽然 5Y 的损伤最初是在 75 万次循环后才被发现，但其他所有材料在 25 万次循环后已经出现了裂纹形成。此外，所有材料的损伤都随着时间的推移呈线性增加。由于 OCT 的浅层光穿透性，仅通过光学显微镜才能观察到外部区域的损伤。
结论
OCT 可用于监测不同 CAD/CAM 材料随时间推移的疲劳损伤，特别是用于检测表面下的损伤。
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