A utilização de um primer autocondicionante como alternativa ao ácido fluorídrico gera vantagens mecânicas e superficiais em cerâmicas vítreas?

Abstract

Objective: This study evaluated the use of a self-etching primer as an alternative to hydrofluoric acid, given the resistance to biaxial bending, roughness and surface topography of lithium disilicate ceramics and those infiltrated by polymers. Methodology: Fifty-four discs (:12mm; thickness: 1.2mm – ISO 6872) were made from two ceramics: IPS e.max CAD (LD – Ivoclar) and Enamic (ceramic infiltrated by polymer – Vita). The samples were randomly distributed into 3 groups, according to the “surface treatment” factor (n = 18 / with n=15, for mechanical tests and n=3, for complementary tests): HF20 - 5% hydrofluoric acid + silane, applied for 20s; HF60 - 5% hydrofluoric acid + silane, applied for 60s; and P - Self-etching ceramic primer. After surface treatment, the discs were cemented in a dentin analogue (G10), which was prepared with a self-etching universal adhesive and, after mechanical cycling (1.2x106 cycles, 50N, 3.8Hz) and subjected to biaxial bending. (EMIC, DL, 1000-1mm/min, 1,000 Kgf). Profilometry, SEM and EDS were also performed as complementary tests. The biaxial flexural strength and roughness data were subjected to analysis of variance (1-factor ANOVA) and the Tukey test (5%). Weibull analysis was performed for biaxial flexural strength data. Results: According to ANOVA, it can be observed that the surface treatment did not significantly influence the biaxial flexural strength of both ceramics: LD (p=0.5552) and PIC (p=0.5205). Despite the manufacturer's instructions regarding the use of HF20 for PIC ceramics, it appears that there was no significant difference in biaxial resistance in the HF60 groups (1240 ± 161 A) compared to the HF20 (1246 ± 207.7 A) and the P (1306 ± 143.3 A). The same can be true for the LD group, where both groups predispose without significant differences. Conclusion: surface treatment did not significantly influence the biaxial flexural strength for the ceramics evaluated. A similarity was observed in relation to biaxial flexural strength when etching with 5% hydrofluoric acid for 20, 60 seconds and self-etching primer, in relation to lithium disilicate ceramics and polymer infiltrated ceramics.