Influência de Recobrimento vítreo e ataque com ácido fluorídrico na topografia final da superfície Y-TZP e qualidade adesiva entre Y-TZP e cimento resinoso

Abstract

The aim of this study was to investigate the effect of hydrofluoric acid etching and glass coating on the ceramic surface, its interaction mechanisms on the Y-TZP surface and the consequence of it on the bond strenght between ceramic and resin cement. Both treatments aim to optimize adhesion at the interface. First it has been found that 10% hydrofluoric acid is capable of changing the ceramic surface after 15 minutes of etching and, for a total removal of silica’s film within the parameters used, a 45 minute exposure to the acid is required. No glass penetration was observed in the ceramic material after infiltração seletiva por vidro protocol. YTZP samples were then divided into 3 groups according to the surface treatment. The three groups had the surface covered with a low melting glass containing silica in their composition. In group 1 the glass was partially removed with 10% hydrofluoric acid for 30 minutes. In group 2 the glass was totally removed, in a total time of 45 minutes, configuring the selective infiltration etching treatment. Group 3 was exposed for 60 minutes, enough time for the surface to be etched by hydrofluoric acid. The bond strength was evaluated from the fracture toughness test. Groups 1 and 2 reached statistically similar values of KIC, while group 3 achieved a statistically higher KIC, than the previous groups. The hydrofluoric acid etching proved to be a possible treatment, altering the surface roughness of the Y-TZP, optimizing adhesion between ceramic and resin cement, while glass, with no penetrating on the material, had only the role of protecting the surface from etching.