Ezzat Yousef, Sharka Rayan, Rayyan Mohammad, Al-Rafee Mohammed
Dentistry, College of Dentistry, Riyadh Elm University, Riyadh, SAU.
Dentistry, College of Dentistry, Umm Al-Qura University, Makkah, SAU.
Cureus. 2021 Dec 23;13(12):e20640. doi: 10.7759/cureus.20640. eCollection 2021 Dec.
Purpose To evaluate the fracture resistance and fracture mode of high-translucency monolithic zirconia (HTZ) crowns and porcelain-veneered zirconia (PVZ) crowns. Material and methods A master die was scanned to design and fabricate the HTZ group (n = 10) and PVZ group (n = 10). Both groups were artificially aged before loaded to fracture. The means of fracture loads of the two groups were compared using an independent t-test at a significance level of 0.05. The mode of fracture was determined using a digital magnifier. Results The mean fracture strength for the HTZ group (4,425 ± 177 newtons (N)) was significantly higher than in the PVZ group (1,798 ± 30.9 N) (p-value < 0.001). All crowns in the HTZ group presented core fracture mode. However, crowns in the PVZ group showed both a core and adhesive fracture mode of 60% and 40%, respectively. Conclusion The fracture strength of HTZ crowns is superior to PVZ crowns. The fracture strength of both types surpassed the maximum bite force in the posterior region, which may be deemed clinically adequate.
目的 评估高透明度全瓷氧化锆（HTZ）全冠和烤瓷贴面氧化锆（PVZ）全冠的抗折强度及折裂模式。材料与方法 扫描主模型以设计并制作HTZ组（n = 10）和PVZ组（n = 10）。两组在加载至折裂前均进行人工老化处理。采用独立样本t检验比较两组的折裂载荷均值，显著性水平为0.05。使用数字放大镜确定折裂模式。结果 HTZ组的平均折裂强度（4425 ± 177牛顿（N））显著高于PVZ组（1798 ± 30.9 N）（p值< 0.001）。HTZ组所有全冠均呈现核部折裂模式。然而，PVZ组全冠核部折裂和粘结剂折裂模式分别占60%和40%。结论 HTZ全冠的抗折强度优于PVZ全冠。两种类型的抗折强度均超过后牙区的最大咬合力，在临床上可认为是足够的。
