Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.
Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA.
J Prosthodont. 2020 Dec;29(9):787-791. doi: 10.1111/jopr.13242. Epub 2020 Oct 6.
To assess the effect of yttria mol% concentration and material thickness on the biaxial fracture load (N) of zirconia with and without mastication simulation.
Disk-shaped specimens (N = 120) of 3 mol% yttria-partially stabilized zirconia, 3Y-PSZ (Katana High Translucent, Kuraray Noritake), 4 mol% yttria-partially stabilized zirconia, 4Y-PSZ (Katana Super Translucent Multi Layered) and 5 mol% Yttria-partially stabilized zirconia, 5Y-PSZ (Katana Ultra Translucent Multi Layered) were prepared to thicknesses of 0.7 and 1.2 mm. For each thickness, the biaxial fracture load (N) was measured with and without mastication simulation with 1.2 million cycles at a 110-N load and simultaneous thermal cycling at 5°C to 55°C. The data were analyzed by three-way Analysis of Variance (α = 0.05) and Tukey-Kramer adjusted multiple comparison test.
Yttria mol% concentration and material thickness had a statistically significant effect on the mean biaxial fracture load (F = 388.16, p < 0.001 and F = 714.33, p < 0.001 respectively). The mean biaxial fracture load ranged from the highest to the lowest; 3Y-PSZ, 4Y-PSZ, and 5Y-PSZ (p = 0.012). The mean biaxial fracture load of the 1.2 mm thickness groups was significantly higher than 0.7 mm thickness at any given condition (p = 0.002). Not all specimens survived the mastication simulation protocol. Fifty percent of the 0.7-mm-thick 4Y-PSZ specimens, 70% of the 0.7-mm-thick 5Y-PSZ specimens and 20% of 1.2-mm-thick 5Y-PSZ specimens fractured during mastication simulation. Mastication simulation had no statistically significant effect on the biaxial fracture load (F = 1.24, p = 0.239) of the survived specimens.
Lowering yttria mol% concentration and increasing material thickness significantly increases the fracture load of zirconia. At 0.7 mm thickness, only 3Y-PSZ survived masticatory simulation. A minimum material thickness of 1.2 mm is required for 4Y-PSZ or 5Y-PSZ.
评估氧化钇摩尔浓度和材料厚度对有和没有咀嚼模拟的氧化锆的双轴断裂载荷（N）的影响。
制备了 3 摩尔%氧化钇部分稳定氧化锆（Katana High Translucent，Kuraray Noritake）、3Y-PSZ、4 摩尔%氧化钇部分稳定氧化锆（Katana Super Translucent Multi Layered）、4Y-PSZ 和 5 摩尔%氧化钇部分稳定氧化锆（Katana Ultra Translucent Multi Layered）的 5Y-PSZ 圆盘形试件，厚度分别为 0.7 和 1.2 毫米。对于每种厚度，在 110-N 载荷下进行 120 万次咀嚼模拟和同时热循环 5°C 至 55°C，测量双轴断裂载荷（N）。使用三因素方差分析（α=0.05）和 Tukey-Kramer 调整多重比较检验对数据进行分析。
氧化钇摩尔浓度和材料厚度对平均双轴断裂载荷有统计学显著影响（F=388.16，p<0.001 和 F=714.33，p<0.001）。平均双轴断裂载荷从最高到最低依次为 3Y-PSZ、4Y-PSZ 和 5Y-PSZ（p=0.012）。任何给定条件下，1.2 毫米厚度组的平均双轴断裂载荷均显著高于 0.7 毫米厚度组（p=0.002）。并非所有试件都能在咀嚼模拟方案中存活。50%的 0.7 毫米厚 4Y-PSZ 试件、70%的 0.7 毫米厚 5Y-PSZ 试件和 20%的 1.2 毫米厚 5Y-PSZ 试件在咀嚼模拟过程中发生断裂。咀嚼模拟对存活试件的双轴断裂载荷（F=1.24，p=0.239）无统计学显著影响。
降低氧化钇摩尔浓度和增加材料厚度可显著提高氧化锆的断裂载荷。在 0.7 毫米厚度时，只有 3Y-PSZ 能在咀嚼模拟中存活。4Y-PSZ 或 5Y-PSZ 需要最小 1.2 毫米的材料厚度。
