The influence of acidogenic challenge on enamel microhardness around restorations

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.

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).

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).

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.