Micron and submicron scale parameters affecting the adhesion of resin composites to dental glass ceramics

Abstract

The adhesion properties of the ceramic restorations play a crucial role in the overall performance and success rate of the treatment. Adhesion is required between the resin cement and tooth substance and indirectly made restoration. The aim of this laboratory study was to investigate the effect of some factors which relate to the bond (adhesion) strength. The study parameters included: 1. The effect of acid etching duration on the surface topography, roughness and wettability 2. The effect of surface neutralization on the wettability of silanes (silane coupling agents), adhesive resin and resin composite cement 3. The degree of resin impregnation into the etched micro-patterns 4. The nano-mechanical properties of the resin-ceramic interface 5. The ceramic-luting cement adhesion (shear bond) strength and 6. The effect of provoked degradation of the interface by exposure to boiling water on nano-mechanical properties and the adhesion strength. Silica based glass ceramics were selected and etching was done with 5% hydrofluoric acid and conditioning was done with two silane coupling agents (experimental and commercial silane coupling agents). Various combinations of silane coupling agents and resin cements were evaluated. Results were statistically analyzed with analysis of variance (ANOVA), the post hoc Tukey’s test, and regression analysis. Etching results showed a significant change in the surface topography and, increase in surface roughness, and wettability with increased etching duration. Neutralizing the ceramic surface did not show significant effect on wettability of silanes and, adhesive resin and resin composite cement. A combination of primer treatment and application of adhesive resin not only showed better resin impregnation into the etched micro-pores but also had high nano-hardness, modulus of elasticity, and adhesion (shear bond) strength.