Evaluation of the bonding effectiveness of a universal adhesive to the plasma‐activated dentin surface

Abstract

AbstractThis study aimed to evaluate the effect of non‐thermal atmospheric pressure plasma on the bond strength of a universal adhesive used in etch‐and‐rinse mode. Dentin surfaces were etched with phosphoric acid and samples were divided into groups exposed to either dry bonding, plasma‐dried bonding, plasma‐dried and rewetted bonding, or wet bonding (n  =  10). Dentin surfaces of the plasma‐dried specimens were treated with a plasma jet before the adhesive procedure. After application, composite blocks were built, and specimens were subjected to micro‐tensile bond strength testing after 24 h and after 10,000 thermal cycles. The hybrid layer formation was evaluated by micro‐Raman spectral analysis; the resin–dentin interface was analyzed by scanning electron microscopy. One‐way ANOVA and Tukey's post hoc multiple comparison tests were used to statistically analyze the data. The bond strength values of the plasma‐dried bonding groups were statistically higher than the non‐plasma‐treated groups both before and after aging. After the thermal cycles, bond strength values decreased significantly only in the wet bonding group. Micro‐Raman spectral analysis revealed that plasma‐drying increased adhesive penetration, especially hydrophobic monomer infiltration. This may increase the mechanical properties and durability of the resin–dentin interface, provide long‐term stability, and improve the polymerization rate of the adhesive layer.