IADR Abstract Archives
Influence of Sintering Conditions on Flexural Strength of Highly-translucent Zirconia
Objectives: The aim of this study was to assess the influence of yttria content and sintering conditions on the biaxial flexural strength of three highly-translucent zirconia grades.
Methods: We prepared zirconia disk-shaped specimens from the following three highly translucent zirconia grades: 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP): Zpex, Tosoh; 5 mol% yttria partially stabilized zirconia (5Y-PSZ): Zpex smile, Tosoh; and 6 mol% yttria partially stabilized zirconia (6Y-PSZ): Lunadent, Kyoritsu. For each highly translucent grade, disk-shaped specimens were sintered at 1450 °C, 1500 °C, 1550 °C, and 1600 °C for 2 hours (n=10). Dimensions of the sintered specimens were 14.5-mm diameter and 1.2-mm thickness. The biaxial flexural strength was measured using a universal material-testing machine, followed by Weibull analysis.
Results: Table summarizes the biaxial flexural strength results from the Weibull analysis. The Weibull analysis revealed that the biaxial flexural strength of 3Y-TZP was the highest, whereas that of 6Y-PSZ was the lowest. Regarding the sintering condition, for both 3Y-TZP (Zpex) and 5Y-PSZ (Zpex Smile), sintering temperature did not affect their biaxial flexural strength. For 6Y-PSZ (Lunadent), on the other hand, sintering temperature higher than 1500 °C significantly decreased their biaxial flexural strength than specimens sintered at 1450 °C.
Conclusions: Increasing yttria contents significantly decreased the biaxial flexural strength of highly translucent zirconia investigated. Sintering temperature did not affect the biaxial flexural strength of 3Y-TZP and 5Y-PSZ, whereas higher sintering temperature significantly decreased that of 6Y-PSZ.
Methods: We prepared zirconia disk-shaped specimens from the following three highly translucent zirconia grades: 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP): Zpex, Tosoh; 5 mol% yttria partially stabilized zirconia (5Y-PSZ): Zpex smile, Tosoh; and 6 mol% yttria partially stabilized zirconia (6Y-PSZ): Lunadent, Kyoritsu. For each highly translucent grade, disk-shaped specimens were sintered at 1450 °C, 1500 °C, 1550 °C, and 1600 °C for 2 hours (n=10). Dimensions of the sintered specimens were 14.5-mm diameter and 1.2-mm thickness. The biaxial flexural strength was measured using a universal material-testing machine, followed by Weibull analysis.
Results: Table summarizes the biaxial flexural strength results from the Weibull analysis. The Weibull analysis revealed that the biaxial flexural strength of 3Y-TZP was the highest, whereas that of 6Y-PSZ was the lowest. Regarding the sintering condition, for both 3Y-TZP (Zpex) and 5Y-PSZ (Zpex Smile), sintering temperature did not affect their biaxial flexural strength. For 6Y-PSZ (Lunadent), on the other hand, sintering temperature higher than 1500 °C significantly decreased their biaxial flexural strength than specimens sintered at 1450 °C.
Conclusions: Increasing yttria contents significantly decreased the biaxial flexural strength of highly translucent zirconia investigated. Sintering temperature did not affect the biaxial flexural strength of 3Y-TZP and 5Y-PSZ, whereas higher sintering temperature significantly decreased that of 6Y-PSZ.