Objective: To evaluate the effect of corrosion products on the microleakage of composite placed adjacent to nondiscolored dentin after amalgam removal.
Method and materials: Sixty Class 2 cavities were prepared on extracted premolars, which were divided into four equal groups according to the manner in which they were restored: group 1, light-cured packable composite (Elite LS) to establish a microleakage baseline; group 2, a high-copper amalgam (World Work) previously stored in 37°C normal saline for 6 months to create amalgam corrosion products; group 3, identical to group 2, but the amalgam was later replaced with composite, leaving the cavity walls intact; and group 4, identical to group 3 except the cavity walls were extended 0.5 mm after amalgam removal prior to insertion of the composite. Groups 1, 3, and 4 were kept in a 37°C normal saline for 1 week. Ten specimens from each of these three groups were randomly selected for dye-extraction testing, while dentin elemental microanalysis of five specimens from all four experimental groups was also conducted. Data were analyzed using ANOVA and the Tukey tests (α = .05).
Results: Corrosion products were not detected in group 4, and no statistically significant difference (P > .05) in microleakage was found between this group and group 1. The highest dye absorbance was associated with group 3 (P < .05).
Conclusion: After amalgam removal, a 0.5-mm extension of the cavity walls could improve the dentinal marginal seal to replicate that of an initial composite restoration.