Efeito do tratamento de superfície na resistência e nas características microestruturais e topográficas de uma cerâmica de dissilicato de lítio reforçada com zircônia

Abstract

The objective of this work was to evaluate the influence of surface treatment on the biaxial flexural strength of zirconia reinforced lithium disilicate ceramics, submitted to mechanical fatigue stress. Were obtained 54 disc-shaped samples of 12 millimeters in diameter by 1.2 millimeters in thickness, divided into three groups (n=18): 5% hydrofluoric acid for 20 seconds and silane (HF20); Hydrofluoric acid 5% for 60 seconds and silane (HF60) and application of ceramic primer (P). Additionally, three samples were included in each group for the purpose of complementary qualitative analyses. The samples were cemented to G10 with Relyx u200 resin cement (3M ESPE) after each surface treatment and were submitted to the mechanical cycling test for 1.0x106 cycles and then to the biaxial flexion test (ISO 6872) immersed in water. The samples assigned to qualitative analyses were submitted to optical profiling, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and subsequently submitted to hardness test and contact angle analysis. The data obtained in this study were submitted to the statistical model of analysis of variance (ANOVA) and Tukey's multiple comparison test. All tests showed statistical differences between the groups used (P<0.05), being the surface treatment with hydrofluoric acid for 20s the most suitable. Thus, it is concluded that the surface treatment alters the roughness, strength, hardness and contact angle of the ceramic involved, and that the surface treatments with better results were the HF20 and P groups.