IADR Abstract Archives
Hydrothermal Aging Effect on Zirconia with Different Compositions
Objectives: Yttria-stabilized zirconia (Y-SZ) materials with different levels of translucency have been used in dentistry/prosthodontics. It is not clear how Y-SZ materials with different compositions respond to artificial aging. The aim of this study was to evaluate the effect of prolonged hydrothermal aging on physical and mechanical properties of dental zirconia.
Methods: Bar-shaped specimens (14×4×2mm) were prepared from four different zirconia-based materials (n=40): Low translucency 3mol% Y-SZ (3Y-LT; Ceramill ZI, Amann Girrbach); High translucency 3mol% Y-SZ (3Y-HT; Ceramill Zolid); and two types of high translucency 5mol% Y-SZ (5YX-HT, Ceramill Zolid-FX white; 5YL-HT, Lava Esthetic, 3M). Fully-sintered specimens were exposed to hydrothermal aging (HA - 0h, 5h, 10h, or 15h at 134°C, 2 bar) and characterized by surface roughness analysis (Alpha-Step D-120, KLA Tencor profilometer), three-point bending strength test (ISO/CD 6872.3), and wettability (surface contact angle by sessile drop technique). Data was analyzed by two-way ANOVA and Tukey HSD (p≤0.05).
Results: Zirconia composition significantly affected roughness (p=0.016). Zirconia*aging interaction affected flexural strength (p=0.012) and surface wettability (p<0.001). The highest and lowest contact angle values were presented by 3Y-LT: 0h/56.6±13.6°; 15h/21.8±4.5°. Similarly, only 3Y-LT flexural strength showed a direct correlation with HA time: 0h/897.0±220.9MPa; 15h/1179.4±99.1 MPa.
Conclusions: Zirconia-based materials with different compositions were affected in different degrees by hydrothermal aging. For low translucency 3mol% Y-SZ, longer aging times were associated with higher flexural strength and wettability, which may indicate the porosity of the substrate. Regardless of the amount of yttria, high-translucency Y-SZ seemed to be less prone to degradation by hydrothermal aging.
Methods: Bar-shaped specimens (14×4×2mm) were prepared from four different zirconia-based materials (n=40): Low translucency 3mol% Y-SZ (3Y-LT; Ceramill ZI, Amann Girrbach); High translucency 3mol% Y-SZ (3Y-HT; Ceramill Zolid); and two types of high translucency 5mol% Y-SZ (5YX-HT, Ceramill Zolid-FX white; 5YL-HT, Lava Esthetic, 3M). Fully-sintered specimens were exposed to hydrothermal aging (HA - 0h, 5h, 10h, or 15h at 134°C, 2 bar) and characterized by surface roughness analysis (Alpha-Step D-120, KLA Tencor profilometer), three-point bending strength test (ISO/CD 6872.3), and wettability (surface contact angle by sessile drop technique). Data was analyzed by two-way ANOVA and Tukey HSD (p≤0.05).
Results: Zirconia composition significantly affected roughness (p=0.016). Zirconia*aging interaction affected flexural strength (p=0.012) and surface wettability (p<0.001). The highest and lowest contact angle values were presented by 3Y-LT: 0h/56.6±13.6°; 15h/21.8±4.5°. Similarly, only 3Y-LT flexural strength showed a direct correlation with HA time: 0h/897.0±220.9MPa; 15h/1179.4±99.1 MPa.
Conclusions: Zirconia-based materials with different compositions were affected in different degrees by hydrothermal aging. For low translucency 3mol% Y-SZ, longer aging times were associated with higher flexural strength and wettability, which may indicate the porosity of the substrate. Regardless of the amount of yttria, high-translucency Y-SZ seemed to be less prone to degradation by hydrothermal aging.