Purpose: To evaluate in situ the anticariogenic effect of fluoride and MDPB containing adhesive systems at the restoration interface, by microhardness tests.
Methods: 120 fragments containing preparations for resin composite restorations performed at the cemento-enamel junction were randomly distributed among the adhesive systems to be tested. The adhesive systems were applied in accordance with the manufacturers' instructions: Optibond FL, Adper Single Bond 2, Prime & Bond 2.1, Optibond Solo Plus, Adper Prompt, Clearfil Protect Bond and restored with the nanoparticulate resin composite Z350. Twenty volunteers used a palatal appliance containing fragments restored with each adhesive system for 21 days, and applied 20% sucrose on them eight times a day to simulate a high cariogenic challenge. Microhardness tests were performed at different depths (20 microm, 40 microm and 60 microm from the occlusal margin of the restoration) and at different distances (100 microm, 200 microm and 300 microm from the adhesive interface).
Results: ANOVA showed that for enamel, there was significant difference between the adhesive systems (P=0.0106); the interaction adhesive system*distance was a significant (P=0.0006), and the one-step self-etching adhesive system containing fluoride (Adper Prompt) presented a higher anticariogenic effect. However, for dentin, the adhesive system used did not interfere in decreasing the severity of caries formation.