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

Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2014Immersion of relined dentures in ethanol solutions has been proposed as post-polymerization treatment to increase materials biocompatibility. The main purpose of this work was to evaluate the effect of ethanol solutions as post-polymerization treatment on the properties of acrylic reline resins (Kooliner, Ufi Gel Hard and Probase Cold): shear bond strength to the denture base resin and the surface free energy. Shear bond strength test was performed on specimens of reline resins attached to denture base resin, after submitted to water, 20%, 50% or 70% ethanol solutions at 55 ºC for 10 minutes (n=10). Controls were left untreated. After this test, the failure mode was assessed. Surface free energy was estimated by contact angles determination, performed by the Wilhelmy plaque technique, on specimens submitted to the treatment with ethanol solutions (n=5). For all resins there were no statistically significant differences (p=0.378) in shear bond strength between groups. However, the Probase Cold showed higher values (p<0.001) than the others. All of the failures were adhesive. All resins showed differences of surface free energy between groups. For Kooliner the water group showed higher results in surface free energy and its polar component than control group (p<0.05). Considering Ufi Gel Hard, treatment with 70% ethanol solution showed significant lower values in surface free energy and its polar component and higher values in the dispersive component. For Probase Cold specific differences of total surface free energy between groups were not followed by an alteration on their components equilibrium. Kooliner showed lower values (p