Postgraduate student, School of Dentistry, University of Ribeirão Preto (UNAERP), Ribeirão Preto, Brazil.
Professor, School of Dentistry, University of Ribeirão Preto (UNAERP), Ribeirão Preto, Brazil.
J Prosthet Dent. 2021 Jan;125(1):117-125. doi: 10.1016/j.prosdent.2019.11.008. Epub 2020 Feb 10.
The mechanical behavior of ceramic endocrowns is unclear.
The purpose of this in vitro and 3-dimensional finite element analysis (3D-FEA) study was to evaluate the mechanical behavior of endodontically treated teeth restored with ceramic endocrowns made by using different computer-aided design and computer-aided manufacturing (CAD-CAM) systems.
Sixty mandibular human molars were endodontically treated, prepared for endocrowns, and divided into 4 groups (n=15) according to the following various ceramic systems: leucite-based glass-ceramic (LC group), lithium disilicate-based glass-ceramic (LD group), glass-ceramic based on zirconia-reinforced lithium silicate (LSZ group), and monolithic zirconia (ZR group). After adhesive bonding, the specimens were subjected to thermomechanical loading and then to fracture resistance testing in a universal testing machine. The failure mode of the specimens was qualitatively evaluated. Three-dimensional FEA was performed to evaluate the stress distribution in each group. Data were analyzed by using a 1-way ANOVA and the Tukey HSD test (α=.05).
Statistically significant differences among the groups were observed (P<.05). The outcomes of the LC, LD, and LSZ groups were similar (1178 N, 1935 N, and 1859 N) but different from those of the ZR group (6333 N). The LC and LD groups had a higher ratio of restorable failures, while LSZ and ZR had more nonrestorable failures. Fractographic analysis indicated a regular failure pattern in the ZR group and irregular failure patterns in the other groups. Three-dimensional FEA revealed similar values and stress pattern distributions among the groups.
The mechanical performance of monolithic zirconia was better than that of the other ceramic endocrowns considered in this research; however, monolithic zirconia presented a higher rate of catastrophic tooth structure failure.
陶瓷嵌体的力学行为尚不清楚。
本体外研究和三维有限元分析（3D-FEA）的目的是评估通过不同的计算机辅助设计和计算机辅助制造（CAD-CAM）系统制作的陶瓷嵌体修复根管治疗后牙齿的力学行为。
60 颗下颌磨牙进行根管治疗，预备制作嵌体，并根据以下不同的陶瓷系统分为 4 组（n=15）：透锂长石基玻璃陶瓷（LC 组）、锂硅二酸盐基玻璃陶瓷（LD 组）、氧化锆增强硅酸锂基玻璃陶瓷（LSZ 组）和整体氧化锆（ZR 组）。粘结后，试件进行热机械加载，然后在万能试验机上进行抗断裂强度测试。定性评估试件的失效模式。通过三维有限元分析评估各组的应力分布。数据采用单因素方差分析和 Tukey HSD 检验（α=.05）进行分析。
组间差异有统计学意义（P<.05）。LC、LD 和 LSZ 组的结果相似（1178 N、1935 N 和 1859 N），但与 ZR 组（6333 N）不同。LC 和 LD 组具有更高的可修复性失败率，而 LSZ 和 ZR 组具有更多的不可修复性失败。断口分析表明 ZR 组具有规则的失效模式，而其他组具有不规则的失效模式。三维有限元分析显示各组的数值和应力分布模式相似。
与本研究中考虑的其他陶瓷嵌体相比，整体氧化锆的力学性能更好，但整体氧化锆更易导致灾难性的牙体结构破坏。
