IADR Abstract Archives
Gradual Glass-Infiltration of Ultra-Translucent Zirconia: Microstructural, Mechanical and Optical Characterization
Objectives: To evaluate the influence of gradual glass-infiltration on the microstructural, optical and mechanical properties of ultra-translucent zirconia (5Y-PSZ).
Methods: One hundred and twenty disc-shaped 5Y-PSZ specimens were obtained through uniaxial pressing. Gradual infiltration was performed on half of the pre-sintered specimens, and samples were divided into four groups according to the sintering protocol: i) 5Y-PSZ at 1450°C/2h; ii) 5Y-PSZ at 1550°C/2h; iii) glass-infiltrated 5Y-PSZ at 1450°C/2h; iv) glass-infiltrated 5Y-PSZ at 1550°C/2h (n=30/group). The crystalline content was characterized using Raman spectroscopy and X-ray diffraction. Biaxial flexural strength test was performed using a piston-on-3-ball fixture following ISO 6872:2016. Weibull statistics were used to determine the characteristic strength and Weibull modulus of tested materials. The optical properties were assessed through reflectance tests, and data was analyzed by ANOVA-one way and Tukey test.
Results: Both glass-infiltrated groups presented significantly higher characteristic strength [glass-infiltrated 5Y-PSZ/1450°C: 1008 (CI 956-1062) MPa; glass-infiltrated 5Y-PSZ/1550°C: 971(CI 922-1023) MPa)], compared to the control groups [5Y-PSZ/1450°C: 560 (CI 539-592) MPa; 5Y-PSZ/1550°C: 524 (CI 500-549) MPa]. XRD spectra and Raman evaluation depicted a predominance of tetragonal zirconia in the infiltrated groups surface and predominant cubic zirconia in the control groups. Glass-infiltration performed at the higher temperature reduced the translucency and increased the contrast ratio compared to the other groups (p<0,05).
Conclusions: Gradual glass-infiltration improved the mechanical properties of ultra-translucent zirconia. Glass-infiltration performed at lower sintering temperature did not jeopardize zirconia’s optical properties.
Methods: One hundred and twenty disc-shaped 5Y-PSZ specimens were obtained through uniaxial pressing. Gradual infiltration was performed on half of the pre-sintered specimens, and samples were divided into four groups according to the sintering protocol: i) 5Y-PSZ at 1450°C/2h; ii) 5Y-PSZ at 1550°C/2h; iii) glass-infiltrated 5Y-PSZ at 1450°C/2h; iv) glass-infiltrated 5Y-PSZ at 1550°C/2h (n=30/group). The crystalline content was characterized using Raman spectroscopy and X-ray diffraction. Biaxial flexural strength test was performed using a piston-on-3-ball fixture following ISO 6872:2016. Weibull statistics were used to determine the characteristic strength and Weibull modulus of tested materials. The optical properties were assessed through reflectance tests, and data was analyzed by ANOVA-one way and Tukey test.
Results: Both glass-infiltrated groups presented significantly higher characteristic strength [glass-infiltrated 5Y-PSZ/1450°C: 1008 (CI 956-1062) MPa; glass-infiltrated 5Y-PSZ/1550°C: 971(CI 922-1023) MPa)], compared to the control groups [5Y-PSZ/1450°C: 560 (CI 539-592) MPa; 5Y-PSZ/1550°C: 524 (CI 500-549) MPa]. XRD spectra and Raman evaluation depicted a predominance of tetragonal zirconia in the infiltrated groups surface and predominant cubic zirconia in the control groups. Glass-infiltration performed at the higher temperature reduced the translucency and increased the contrast ratio compared to the other groups (p<0,05).
Conclusions: Gradual glass-infiltration improved the mechanical properties of ultra-translucent zirconia. Glass-infiltration performed at lower sintering temperature did not jeopardize zirconia’s optical properties.