EVALUACIÓN IN VITRO DEL EFECTO DE LA CONCENTRACIÓN Y EL TIEMPO DE APLICACIÓN DEL ÁCIDO FLUORHÍDRICO SOBRE LA ADHESIÓN AL DISILICATO DE LITIO/IN VITRO EVALUATION OF THE EFFECT OF HYDROFLUORIC ACID CONCENTRATION AND APPLICATION TIME ON ADHESION TO LITHIUM DISILICATE

The purpose of this study was to perform in vitro assessment of the effect of 4.6% and 9.5% hydrofluoric acid at 20 s, 40 s and 60 s on the surface of lithium disilicate during the processes of adherence to a resinous substrate. The ceramic cubes were subjected to surface treatment obtaining 6 groups: control group and groups 2 and 3 were treated with 4.6% hydrofluoric acid during 20, 40 and 60 seconds respectively, and groups 4, 5 and 6 were treated with 9.5% hydrofluoric acid at 20 s, 40 s and 60 s. Porcelain cubes were cemented with the resin ones with self-adhesive resin cement and bars of 1 x 1 x 18 mm were produced. Adhesive strength was measured. Adhesive strength values expressed in MPa were as follows: G1 = 26.69, G2 = 23.93, G3 = 20.90, G4 = 17.56, G5 = 16.30, G6 = 18.78, with significant differences between group 1 and groups 4-5.