Shear bond strength of current adhesive systems to enamel, dentin and dentin-enamel junction region.

This study investigated the bonding of current resin adhesives to the region approximating the dentin-enamel junction (DEJ), where the etch pattern to enamel or dentin may be different. Three kinds of tooth substrates were chosen for testing: enamel, dentin and the DEJ region. A self-etching primer system (Clearfil SE Bond) and two total-etch wet bonding systems (Single Bond and One-Step) were used. Each tooth region was bonded with one of the adhesive systems, and a resin composite and was subjected to a micro-shear bond test. In addition, morphological observations were performed on debonded specimens and etched surfaces using confocal laser scanning microscopy (CLSM). CLSM observations showed that the DEJ region was etched more deeply by phosphoric acid gel than enamel or dentin, suggesting that the action of acid etch seemed to be more intense on the DEJ. However, no statistically significant differences of shear bond strength values were observed between the DEJ region and enamel or dentin, or the adhesive systems used (p>0.05). Bonding to the DEJ is potentially as good as that to enamel or dentin.