Adhesion evaluation of dentin sealing, micropermeability, and bond strength of current HEMA-free adhesives to dentin

Purpose: To evaluate dentin sealing (DS), micropermeability (MP), and dentin bond strength (BS) of HEMA-free adhesives after 24 h and one year of artificial saliva storage. Materials and Methods: Two HEMA-free (G-ænial Bond and BeautiBond) and All-Bond 3 (the bottle of resin is HEMAfree) adhesives were tested. Adper Single Bond 2, a HEMA-containing adhesive, served as the control. All adhesives were applied according to the manufacturers' instructions and teeth were prepared for DS (n = 5), MP (n = 5), and BS testing (n = 10). DS under a pulpal pressure of 10 psi was performed at 4 time points (when smear layer was present, after EDTA treatment, after adhesive application, and after 1 year). MP was assessed using pulpal pressure of a 20-cm aqueous dye-solution column and confocal laser scanning microscopy. DS, MP, and BS were performed after 24 h or one-year storage. BS and DS data were statistically analyzed using two-way ANOVA, the Tukey-Kramer test (for BS) and Tukey's post-hoc test (for DS) (α = 0.05). A qualitative MP assessment was performed by comparing the accumulation of yellow dye within the resin-dentin interface. Results: Adper Single Bond 2 and All-Bond 3 completely sealed the dentin at 24 h and one year. G-ænial Bond showed statistically significant DS reduction of approximately 15% after one year. BeautiBond showed no DS reduction after one year. The resin-dentin interface created using Adper Single Bond 2 and GA showed dye accumulation primarily after one year. The mean BS of All-Bond 3 was statistically significantly higher than that of other adhesives, while G-ænial Bond and BeautiBond showed statistically significantly lower mean bond strengths than did Adper Single Bond 2 and All-Bond 3. After one-year storage, the mean BS was statistically significantly lower only for G-ænial Bond. Conclusion: DS, MP, and BS were not influenced by the absence of HEMA in the tested adhesives.