A influência do número de queimas e da caracterização extrínseca na rugosidade de uma cerâmica à base de silicato de lítio reforçada por zircônia

Abstract

The aim of the study was to evaluate the surface roughness of a zirconia-reinforced lithium silicate ceramic (ZLS) after extrinsic characterization and multiple firing. ZLS (VITA Suprinity) ceramic blocks were rounded and sliced to obtain 90 discs with 12 mm in diameter and 1.2 mm in thickness, distributed in 6 groups (n = 15) according to the surface treatment (CO: Control - without pigmentation; DF - “Double Firing”: crystallization and pigmentation performed in separate steps; SF - “Single Firing”: crystallization and pigmentation in a single step;) and number of firings (II - 2 fires; IV - 4 fires): COII, COIV, DFII, DFIV, SFII and SFIV. The samples were then subjected to the roughness analysis (profilometry). The data obtained were submitted to statistical analysis of variance (ANOVA), Tukey's test and t-test (α = 5%). The results obtained revealed that both types of treatments performed for pigmentation increased the roughness of the ceramic (p<0.01), with the DF group having the greatest increase in roughness. The number of burns influenced the surface roughness (DFII: 122 μm; DFIV: 77 μm; p <0.01) only in the DF groups. It was concluded that the extrinsic characterization promotes an increase in surface roughness and that the technique that obtained the best results of extrinsic characterization of lithium silicate ceramics reinforced by zirconia, regarding surface roughness, was that of the SF group.