Nanotube-modified dentin adhesive—Physicochemical and dentin bonding characterizations.

Abstract: Objective: The aim of this study was to investigate the effect of aluminosilicate clay nanotubes (Halloysite, HNT) incorporated into the adhesive resin of a commercially available three-step etch and rinse bonding system (Adper Scotchbond Multi-Purpose/SBMP) on dentin bond strength, as well as the effect on several key physicochemical properties of the modified adhesive. Methods: Experimental adhesives were prepared by adding five distinct HNT amounts (5–30wt.%) into the adhesive resin (w/v) of the SBMP dentin bonding system. Bond strength to human dentin, microhardness, and degree of conversion (DC) of the modified adhesives were assessed. Results: From the shear bond strength data, it was determined that HNT incorporation at a concentration of 30wt.% resulted in the highest bond strength to dentin that was statistically significant (p =0.025) when compared to the control. Even though a significant increase in microhardness (p <0.001) was seen for the 30wt.% HNT-incorporated group, a significantly lower DC (p <0.001) was recorded when compared to the control. Significance: It was concluded that HNT can be incorporated up to 20wt.% without jeopardizing important physicochemical properties of the adhesive. The modification of the SBMP dentin bonding agent with 20wt.% HNT appears to hold great potential toward contributing to a durable dentin bond; not only from the possibility of strengthening the bond interface, but also due to HNT intrinsic capability of encapsulating therapeutic agents such as matrix metalloproteinase (MMP) inhibitors. [Copyright &y& Elsevier]