Comportamento de fadiga de uma cerâmica de uma cerâmica à base de silicato comportamento de fadiga de uma cerâmica à base de silicato de lítio e zircônia -

Abstract

To evaluate the fatigue behavior of zirconia-reinforced lithium silicate ceramic (ZLS - VITA Suprinity, Vita Zahnfabrik), using the boundary and staircase methods. Methods: One hundred and twenty five ZLS ceramic bars with the dimensions of 18 mm x 4 mm x 1.2 mm were produced. Thirty specimens were tested for three-point bending using a universal testing machine in 37oC distilled water. Flexural strength data were analysed using Weibull statistics. Ninety five bars were subjected to cyclic fatigue using boundary and staircase methods. Fatigue tests were performed on a pneumatic cycling machine with a frequency of 2 Hz in 37oC distilled water. Two lifetimes were evaluated in each method, 10³ and 104cycles. Vickers hardness (HV) was evaluated using a microdurometer with a load of 4.9 N for 20 s.Fractographic analysis and EDS analysis of the specimens were also performed. Results: ZLS obtained a mean flexural strength of 178 MPa, Weibull modulus of 4 and HV of 680 MPa. After 103 cycles, for both methods, there was a degradation of 78% of the initial flexural strength. There was no significant degradation when the cycling time increased from 103 to 104cycles. For both the staircase and boundary methods, the stress for a failure probability of 50% (50%) after 10 cycles was 39