The Effect of Ethanol Associated with Universal Adhesive on Resin Composite Adhesion to Different Dentin Depths: A Long-Term In Vitro Study.

To evaluate the ethanol wet-bonding protocol with a universal adhesive in etch-andrinse and self-etch modes on microleakage and microtensile bond strength (μTBS) of resin composite to different dentin depth. Molars were distributed into groups according to protocol and dentin depth: universal adhesive (C - control), ethanol + universal adhesive (E), and phosphoric acid etch + ethanol + universal adhesive (PA+E). All protocols were applied to dentin at superficial, middle and deep depths. The specimens (n = 10) were submitted to microleakage and μTBS tests. Half of specimens were submitted to thermocycling (10,000 cycles; 5∘C/55∘C). Data were submitted to Spearman correlation (μTBS x microleakage) and three-way ANOVA (protocol, aging and depth), followed by Bonferroni post hoc test (α=0.05). PA+E group showed highest μTBS and lowest microleakage mean values in 24h. All groups presented similar μTBS mean values after thermocycling. The deep dentin showed less stable μTBS results. PA+E group presented highest microleakage mean values after thermocycling. Spearman's correlation showed a strong correlation between microleakage and μTBS. The PA+E group improved immediate adhesion and E group promoted a more stable μTBS in the long-term adhesion of universal adhesive. The aging for all protocols jeopardized the stability of the hybrid layer. The ethanol wet bonding technique associated with universal adhesive has enhanced the immediate result of the resin composite adhesion.