Effect of dentin location and long-term water storage on bonding effectiveness of dentin adhesives

Abstract

Dentin is a variable substrate with properties that change considerable in a single surface. The purpose of this study was to evaluate the bonding effectiveness to these different dentin locations and evaluate these differences over time. After bonding procedures with five different adhesives, small micro-tensile bond strength (μTBS) beams were prepared and dichotomously divided in 'center' and 'periphery' dentin specimens. After 1 week, 3, 6 and 12 months of water storage the μTBS of specimens of each group was determined, enabling a paired study design. The bond strengths of both etch&rinse adhesives were insensitive to regional variability. For the two-step self-etch adhesives, a marked increase in bond strengths was observed with increasing amount of intertubular dentin. Regional variability did not affect the long-term bonding effectiveness for any of the adhesives tested. In conclusion, only for the mild self-etch adhesives, μTBS to 'periphery' dentin was higher than for the 'center' specimens.