Effect of ethanol solutions as post-polymerization treatment on the properties of acrylic reline resins

Objectives To evaluate the effect of ethanol solutions as post-polymerization treatment on the shear bond strength and the surface free energy of acrylic reline resins. Methods Three reline resins (Kooliner, Ufi Gel Hard and Probase Cold) were manipulated and attached to 150 parallelepipeds denture base resin previously aged. Constructed specimens of each resin were randomly divided into control group (left untreated) or experimental groups subjected to different treatments: immersion in water or ethanol solutions 20, 50 or 70% at 55 °C for 10 min (n = 10). Shear bond strength was tested and the failure mode was assessed. Surface free energy was calculated by determining the contact angle and estimated by the Wilhelmy plaque technique (n = 5). Data were analyzed using Kruskal–Wallis and Mann–Whitney tests with Bonferroni correction (alfa = 0.05). Results Probase Cold showed higher values (p < 0.001) in shear bond strength than other resins. There were no statistically significant differences (p = 0.378) in shear bond strength between post-polymerization treatments. Kooliner showed lower values (p < 0.001) in surface free energy than other resins. Considering the post-polymerization treatment groups, there were no statistically significant differences (p > 0.05) in surface energy. Conclusions Ethanol solutions as post-polymerization treatments did not deteriorate the bond strength of acrylic reline resins to denture base and neither their wettability.