RESUMO
PURPOSE: The purpose of this study was to evaluate the influence of acidogenic challenge on microhardness of enamel adjacent to adhesive restorations in primary and permanent teeth. METHODS: Occlusal cavities were prepared and immediately restored with two adhesive systems and a composite resin. The specimens were divided into eight groups, according to the type of tooth (primary or permanent), adhesive system (etch-and-rinse or self-etching), and treatment (control or acidogenic challenge). The cariogenic challenge groups were submitted to pH cycling for 10 days. The teeth were prepared for a cross-section microhardness test. Analysis of variance and Tukey's post hoc test were used to analyze the data (α=5 percent). RESULTS: The adhesive systems did not influence the enamel microhardness (P<.27). Primary teeth were more susceptible to acidogenic challenge (P=.004). The microhardness values for control groups were statistically similar at different indentation depths (P>.05); however, in the acidogenic challenge groups, lower microhardness values were observed in superficial measurements (P<.05). CONCLUSIONS: Acidogenic challenge negatively influenced the microhardness of the enamel surface adjacent to adhesive restorations. Mineral loss was higher in primary teeth and on the enamel surface.