In vitro evaluation of enamel microhardness adjacent to restorations after cariogenic challenge

Purpose: This in vitro study used microhardness testing to assess the enamel demineralization induced by artificial caries lesions adjacent to restorative materials. Methods: Two conventional (MAXXION R® and VIDRION R®) and one resin-modified (VITREMER®) glass ionomer cements and one non-fluoridated composite resin (Z-250®) were tested. Standard cavities were prepared in 160 bovine enamel blocks. The enamel blocks were randomly divided into 4 experimental groups (n=40) according to the material used. After the initial microhardness measurement, the enamel blocks were restored and subjected to thermal and pH cycling, simulating cariogenic challenge. Microhardness measurements were performed on the enamel blocks to calculate the loss of enamel surface hardness. Data were analyzed by analysis of variance and Tukey test (? VIDRION R > MAXXION R. Conclusion: The enamel adjacent to the conventional glass ionomer cements showed less demineralization than the enamel adjacent to resin-modified materials. Key words: Caries inhibition; fluoride; glass-ionomer cements