Mechanical behavior and microstructural characterization of different zirconia polycrystals in different thicknesses
10.4047/jap.2021.13.6.385
- Author:
Laura Viviana Calvache ARCILA
1
;
Nathália de Carvalho RAMOS
;
Tiago Moreira Bastos CAMPOS
;
Kiara Serafini DAPIEVE
;
Luiz Felipe VALANDRO
;
Renata Marques de MELO
;
Marco Antonio BOTTINO
Author Information
1. Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, São José Dos Campos, Brazil
- Publication Type:Original Article
- From:The Journal of Advanced Prosthodontics
2021;13(6):385-395
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE:To characterize the microstructure of three yttria partially stabilized zirconia ceramics and to compare their hardness, indentation fracture resistance (IFR), biaxial flexural strength (BFS), and fatigue flexural strength.
MATERIALS AND METHODS:Disc-shaped specimens were obtained from 3Y-TZP (Vita YZ HT), 4Y-PSZ (Vita YZ ST) and 5Y-PSZ (Vita YZ XT), following the ISO 6872/2015 guidelines for BFS testing (final dimensions of 12 mm in diameter, 0.7 and 1.2 ± 0.1 mm in thicknesses). Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed, and mechanical properties were assessed by Vickers hardness, IFR, quasi-static BFS and fatigue tests.
RESULTS:All ceramics showed similar chemical compositions, but mainly differed in the amount of yttria, which was higher as the amount of cubic phase in the diffractogram (5Y-PSZ > 4Y-PSZ > 3Y-TZP). The 4Y- and 5Y-PSZ specimens showed surface defects under SEM, while 3Y-TZP exhibited greater grain uniformity on the surface. 5Y-PSZ and 3Y-TZP presented the highest hardness values, while 3Y-TZP was higher than 4Y- and 5Y-PSZ with regard to the IFR. The 5Y-PSZ specimen (0.7 and 1.2 mm) showed the worst mechanical performance (fatigue BFS and cycles until failure), while 3Y-TZP and 4Y-PSZ presented statistically similar values, higher than 5Y-PSZ for both thicknesses (0.7 and 1.2 mm). Moreover, 3Y-TZP showed the highest (1.2 mm group) and the lowest (0.7 mm group) degradation percentage, and 5Y-PSZ had higher strength degradation than 4Y-PSZ group.
CONCLUSION:Despite the microstructural differences, 4Y-PSZ and 3Y-TZP had similar fatigue behavior regardless of thickness. 5Y-PSZ had the lowest mechanical performance.
