The effect of various treatments on composite materials in bonding with resin cements.

The present study investigated the influence of surface treatments of composite materials using 6% hydrofluoric acid or 2% acidulated phosphate fluoride, the influence of the application of a bonding agent to the surface, and the influence of incremental curing of composite materials on the shear bonding strength between composite materials and resin cements. These results were studied statistically by analyzing variances in three-way classification and by their contributory ratios. The effects of hydrofluoric acids or acidulated phosphate fluorides on the treated surfaces of composite materials, and also the interfaces between composite materials and resin cements were further examined by mean of scanning electron microscopy (SEM). Unlike the controls, surfaces of all specimens treated with hydrofluoric acid or fluoride revealed micro-porous surfaces, but the effect of the surface treatment on the bonding strength was not equal for all the composite materials tested. The application of a bonding agent influenced some composite material, but the incremental curing of composite materials had no influence on bonding with resin cements.