Department of Gerodontology and Home Care Dentistry, Aichi Gakuin University School of Dentistry, Nagoya, Japan.
Department of Dental Materials Science, Aichi Gakuin University School of Dentistry, Nagoya, Japan.
J Prosthodont Res. 2021 Oct 15;65(4):509-514. doi: 10.2186/jpr.JPR_D_20_00183. Epub 2021 Mar 9.
Purpose This study aimed to evaluate the effects of degradation on the strength of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite blocks (RCBs) by subjecting them to accelerated degradation in water and conducting biaxial flexural strength tests.Methods Six commercial RCBs were tested. The RCBs were cut into disks, after which the disks were immersed in purified water. For the aging experiment, the samples were subjected to heat treatment at 37, 60, 70, and 80 °C, in a constant temperature oven and stored statically for 30 d. After the aging experiment, the elements released from the RCB fillers were measured by inductively coupled plasma atomic emission spectroscopy. In addition, the biaxial flexural strength of the RCB fillers was measured after accelerated degradation at 70 °C.Results Si (the main component of the filler) was detected in all the RCB solutions after the aging experiment; however, the type and amount of other elements differed considerably among the RCBs. The flexural strength of some of the RCBs decreased by approximately 20-40% after the accelerated degradation. For most materials, the Weibull coefficient decreased or remained unchanged after the test, whereas it increased in some materials.Conclusions The strength of all the RCBs decreased after the accelerated degradation tests; however, this behavior differed among the materials. In addition, the release of elements from the filler of some of the materials into the water correlated with the decrease in the strength of these materials. These findings indicate that the evaluation of the degradation behavior of RCBs in water is essential for their long-term usage.
目的 本研究旨在通过对计算机辅助设计/计算机辅助制造（CAD/CAM）树脂复合块（RCB）进行加速水降解，并进行双轴弯曲强度测试，评估降解对其强度的影响。
方法 测试了 6 种商业 RCB。将 RCB 切割成圆盘，然后将圆盘浸入去离子水中。对于老化实验，将样品在 37、60、70 和 80°C 的恒温烘箱中进行热处理，并静态储存 30 天。老化实验后，通过电感耦合等离子体原子发射光谱法测量 RCB 填料释放的元素。此外，在 70°C 下加速降解后测量 RCB 填料的双轴弯曲强度。
结果 在老化实验后，所有 RCB 溶液中均检测到 Si（填料的主要成分）；然而，不同 RCB 之间其他元素的类型和数量差异很大。一些 RCB 的弯曲强度在加速降解后下降了约 20-40%。对于大多数材料，威布尔系数在测试后降低或保持不变，而在一些材料中则增加。
结论 所有 RCB 的强度在加速降解测试后均下降；然而，这种行为在材料之间存在差异。此外，一些材料的填料中元素的释放与这些材料强度的下降有关。这些发现表明，评估 RCB 在水中的降解行为对于其长期使用至关重要。
