Effect of smear layer characteristics on dentin bonding durability of HEMA-free and HEMA-containing one-step self-etch adhesives

Abstract

The purpose of this study was to evaluate the effect of smear layer characteristics on the dentin bonding durability of HEMA-free and HEMA-containing one-step self-etch adhesives. Xeno V (XV; HEMA-free), G BOND PLUS (GB; HEMA-free) and Clearfil S³ Bond (S³; HEMA-containing), were applied to dentin surfaces prepared with either #180- or #600-grit SiC paper according to manufacturers’ instructions. Bond strengths to dentin were determined using μTBS test after 24-hour, 6-month, and 1-year water storage. In addition, nanoleakage evaluation was performed using an SEM. The smear layer characteristics affected water-tree nanoleakage formation in the adhesive layers of XV and GB, which contributed to a reduction in μTBS after 6-month water storage, while the characteristics did not affect the μTBS of S³. However, regardless of the smear layer characteristics, 1-year water storage significantly reduced the μTBS of all the adhesives and was associated with an increase in failures at the adhesive-composite interface.