Nishioka Gabriela, Prochnow Catina, Firmino Aline, Amaral Marina, Bottino Marco Antonio, Valandro Luiz Felipe, Renata Marques de Melo
Universidade Estadual Paulisa - Unesp, Faculty of Odontology, Department of Dental Materials and Prosthodontics, São José dos Campos, SP, Brazil.
Universidade Federal de Santa Maria - UFSM, Faculty of Odontology, Department of Restorative Dentistry, Santa Maria, RS, Brazil.
Braz Oral Res. 2018 Jun 11;32:e53. doi: 10.1590/1807-3107bor-2018.vol32.0053.
This in vitro study evaluated the fatigue strength of different ceramic materials indicated for monolithic restorations. Disc-shaped specimens were made according to ISO 6872 from five different ceramic materials: feldspathic ceramic (FC), polymer-infiltrated ceramic network (PIC), lithium disilicate glass-ceramic (LD), zirconia-reinforced lithium silicate glass-ceramic (ZLS), and high translucent tetragonal zirconia polycrystals doped by yttrium (YZ-HT). After obtaining the mean of each material (n = 5) from monotonic load-to-failure tests, specimens (n = 20) were subjected to fatigue tests (staircase method) using a biaxial flexural setup (piston-on-three-balls), to determine the fatigue strength. The parameters used for fatigue tests were: 100,000 cycles at 10 Hz, initial load of ~ 60% of mean load-to-failure, and step size of 5% of the initial load (specific for each ceramic material). Kruskal-Wallis and Bonferroni's test (α = 0.05) were used to analyze the fatigue strength data. Fatigue strength (MPa) of the materials was statistically different among each other as follows: YZ-HT (370.2 ± 38.7) > LD (175.2 ± 7.5) > ZLS (152.1 ± 7.5) > PIC (81.8 ± 3.9) > FC (50.8 ± 1.9). Thus, it can be concluded that, in terms of fatigue, high translucent polycrystalline zirconia is the best choice for monolithic restorations as it bears the highest load before cracking/fracturing.
这项体外研究评估了适用于整体修复的不同陶瓷材料的疲劳强度。根据ISO 6872标准，用五种不同的陶瓷材料制作了圆盘形试样：长石质陶瓷（FC）、聚合物渗透陶瓷网络（PIC）、二硅酸锂微晶玻璃（LD）、氧化锆增强二硅酸锂微晶玻璃（ZLS）和钇掺杂的高透 tetragonal氧化锆多晶体（YZ-HT）。在从单调加载至破坏试验中获得每种材料的平均值（n = 5）后，对试样（n = 20）使用双轴弯曲装置（三球上活塞法）进行疲劳试验（阶梯法），以确定疲劳强度。用于疲劳试验的参数为：10 Hz下100,000次循环，初始载荷约为平均破坏载荷的60%，步长为初始载荷的5%（每种陶瓷材料特定）。使用Kruskal-Wallis检验和Bonferroni检验（α = 0.05）分析疲劳强度数据。材料的疲劳强度（MPa）在彼此之间存在统计学差异，如下所示：YZ-HT（370.2 ± 38.7）> LD（175.2 ± 7.5）> ZLS（152.1 ± 7.5）> PIC（81.8 ± 3.9）> FC（50.8 ± 1.9）。因此，可以得出结论，就疲劳而言，高透多晶氧化锆是整体修复的最佳选择，因为它在开裂/断裂前承受的载荷最高。
