Masuda Tomotoshi, Nomoto Syuntaro, Sato Toru, Kanda Yuuhei, Sakai Takanori, Tsuyuki Yu
Department of Fixed Prosthodontics, Tokyo Dental College.
Bull Tokyo Dent Coll. 2019 Feb 28;60(1):17-27. doi: 10.2209/tdcpublication.2018-0022. Epub 2019 Jan 31.
The purpose of this study was to investigate the influence of differences in axial thickness and type of cement on fracture load in CAD/CAM crowns. Assuming the mandibular first premolar to be the abutment tooth, 4 types of crown with different axial thicknesses and radii of curvature were prepared. To unify external design, the morphology of the crown margins was set at 0.15, 0.30, 0.45, or 0.60 mm, thus maintaining uniform axial form of the crowns. The CAD/CAM crowns and abutment teeth were bonded using each of 2 types of resin cement or polycarboxylate cement. The fracture load value was measured using a universal testing machine and the destruction phase observed.No significant difference was observed with change in axial thickness. The fracture load values with each of the 2 types of resin cement used were significantly higher than that with polycarboxylate cement (p<0.01). These results suggest that the fracture load values of CAD/CAM crowns are not influenced by differences in the axial thickness of the crown, and that they are higher when bonding is achieved with resin rather than polycarboxylate cement.
本研究的目的是调查轴向厚度和粘结剂类型的差异对计算机辅助设计/计算机辅助制造（CAD/CAM）全冠折裂载荷的影响。假设下颌第一前磨牙为基牙，制备了4种具有不同轴向厚度和曲率半径的全冠。为统一外部设计，将全冠边缘形态设置为0.15、0.30、0.45或0.60mm，从而保持全冠轴向形态的一致。使用2种树脂粘结剂或聚羧酸锌粘结剂分别粘结CAD/CAM全冠和基牙。使用万能试验机测量折裂载荷值并观察破坏阶段。未观察到轴向厚度变化有显著差异。使用的2种树脂粘结剂各自的折裂载荷值均显著高于聚羧酸锌粘结剂（p<0.01）。这些结果表明，CAD/CAM全冠的折裂载荷值不受全冠轴向厚度差异的影响，并且当使用树脂而非聚羧酸锌粘结剂进行粘结时，折裂载荷值更高。
