Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.
Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.
Dent Mater J. 2022 May 31;41(3):466-472. doi: 10.4012/dmj.2021-224. Epub 2022 Mar 4.
To evaluate the fracture resistance of computer-aided design and computer-assisted manufacturing restorations as the abutment of removable partial dentures, experimental blocks, with the rest seat made of feldspar, hybrid resin composite, lithium disilicate glass ceramic, or zirconia, were subjected to loading by a metallic occlusal rest. The rest contacted the rest seat with an accurate fit and two mismatch contact conditions: bottom and sidewall contact. Zirconia exhibited the highest fracture load, and the fracture load of the accurate fit was significantly higher than that of the sidewall contact (p<0.05) and insignificantly higher than that of the bottom contact (p>0.05). A finite element analysis of the sidewall contact revealed a higher tensile stress concentration at the bottom of the rest seat than the other contact conditions. The mismatch between the rest and the restoration reduced fracture resistance, while zirconia as the abutment withstood the average occlusal force of the posterior region.
为评估计算机辅助设计和计算机辅助制造修复体作为可摘局部义齿基牙的抗折能力，用长石、混合树脂复合材料、锂硅玻璃陶瓷或氧化锆制作的实验块，用金属咬合支托进行加载。支托与修复体的支托面精确贴合，并模拟两种不匹配的接触情况：底部接触和侧壁接触。氧化锆的折断负荷最高，精确贴合的折断负荷明显高于侧壁接触（p<0.05），与底部接触无显著差异（p>0.05）。侧壁接触的有限元分析显示，支托底部的拉伸应力集中高于其他接触情况。支托与修复体之间的不匹配降低了抗折能力，而氧化锆作为基牙可承受后牙区的平均咀嚼力。
