Effects of remaining dentin thickness, smear layer and aging on the bond strengths of self-etch adhesives to dentin

Abstract

This study evaluated the effects of remaining dentin thickness (RDT), different smear layers, and aging on the microtensile bond strength (^TBS) of universal adhesives to dentin when applied in self-etch mode. Ninety-six human third molars were randomly allocated to 12 groups (n=8) based on adhesives: Clearfil™ SE Bond 2 (SE, control), Clearfil™ Universal Bond (CU) and ScotchBond™ Universal Adhesive (SB); smear layers: Prepared either with 600-grit SiC paper (P) or regular diamond bur (B); and aging: Stored in distilled water at 37°C for 24 hours (24h) or 1 year (1y). ^TBS was significantly affected by the type of adhesives, smear layers, and aging (p<0.001). A statistically significant and positive linear relationship was also observed between ^TBS and RDT (p<0.05) in all the tested groups, except for SEBly and CUB24h (p>0.05). RDT, smear layer types, and aging can influence the bonding performances of universal adhesives when applied in self-etch mode.