Pre-etching vs. grinding in promotion of adhesion to intact enamel using self-etch adhesives

This study was aimed to determine the effectiveness of grinding and pre-etching in promotion of adhesion to human intact enamel using the self-etch adhesive (SEA) Adper Easy Bond (3M ESPE). Etch-and-rinse adhesive Adper Single Bond (3M ESPE) served as control. Composite cylinders (AP-X Kuraray) were built and after 24 h micro-shear bond strengths (MSBS) were measured. Bonding interfaces were evaluated under scanning electron microscope (SEM). For evaluation of average roughness (Ra) and morphological analysis, treated enamel surfaces were observed under SEM and confocal laser scanning microscope (CLSM) with 3D surface profiling. Highest bond strengths were obtained by pre-etching and grinding showed a less significant role. Phosphoric acid (PA) etching compare to grinding created significantly rougher surface (Ra: 0.72 and 0.43 μm respectively). Therefore, this study recommends pre-etching the intact enamel prior to application of the adhesive instead of grinding.