Department of Operative Dentistry, Faculty of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Department of Operative Dentistry, Faculty of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.
J Mech Behav Biomed Mater. 2023 Oct;146:106101. doi: 10.1016/j.jmbbm.2023.106101. Epub 2023 Aug 29.
The aim of the present study was to evaluate the impact of two Er,Cr:YSGG laser surface treatments on the repair bond strength of a dental CAD/CAM resin composite (Brilliant Crios) after artificial aging. Twenty-four resin-based CAD/CAM blocks were cut and 48 rectangular slabs (3 x 12 x 14 mm) were prepared. Preliminary SEM observations indicated the most favorable laser settings regarding surface modification of the tested restorative material. The CAD/CAM specimens were then divided into 4 groups (n=12) based on their surface pretreatment: no treatment, air abraded with 50-μm AlO particles, and laser irradiated with two different protocols using Er,Cr:YSGG laser with average power 3.5 and 4.5 W, pulse repetition rate 35 and 50 Hz, and pulse energy 100 and 90 mJ, respectively. After surface treatments each group followed a bonding protocol with silane and a flowable resin composite was used to prepare 48 microrods. Half of the microrods of each group were subjected on shear bond strength (SBS) test (chisel-shaped blade, load cell of 500 N, crosshead speed of 1 mm/min) after 24 h, while the other half underwent artificial aging (15,000 cycles, 5-55 °C) and then SBS test. The debonded specimens were examined under an optical microscope to determine the failure mode. All specimens were also evaluated using SEM to assess the surface topography after the treatments. The results showed that SBS significantly decreased after thermocycling in all the experimental groups (p<0.05). Control group presented much lower SBS values than the other groups after both 24 h and thermocycling (p<0.05). The highest values of SBS exhibited air-abrasion group (p<0.05), followed by the two laser groups, which did not differ to each other (p>0.05). The results of the current study indicated that Er,Cr:YSGG laser irradiation can be an alternative treatment for repairing the tested resin-based CAD/CAM restorative material.
本研究旨在评估两种 Er,Cr:YSGG 激光表面处理对人工老化后牙科 CAD/CAM 树脂复合材料（Brilliant Crios）修复粘结强度的影响。切割 24 个树脂基 CAD/CAM 块，并制备 48 个矩形薄片（3 x 12 x 14mm）。初步的 SEM 观察表明，激光设置最有利于测试修复材料的表面改性。然后，根据表面预处理将 CAD/CAM 标本分为 4 组（n=12）：无处理、用 50-μm AlO 颗粒喷砂、用 Er,Cr:YSGG 激光以两种不同的方案照射，平均功率分别为 3.5 和 4.5W、脉冲重复率分别为 35 和 50Hz、脉冲能量分别为 100 和 90mJ。表面处理后，每组均采用硅烷粘结协议，并用可流动树脂复合材料制备 48 根微棒。每组的一半微棒在 24 小时后进行剪切粘结强度（SBS）测试（凿形刀片，500N 测力单元，十字头速度 1mm/min），另一半进行人工老化（15000 次循环，5-55°C），然后进行 SBS 测试。用光学显微镜检查离解的标本，以确定失效模式。所有标本均用 SEM 评估处理后的表面形貌。结果表明，所有实验组经热循环后 SBS 均显著降低（p<0.05）。对照组在 24 小时和热循环后均显示出比其他组低得多的 SBS 值（p<0.05）。SBS 值最高的是喷砂组（p<0.05），其次是两种激光组，它们之间没有差异（p>0.05）。本研究结果表明，Er,Cr:YSGG 激光照射可为修复测试的基于树脂的 CAD/CAM 修复材料提供替代治疗。
