In vitro evaluation of microleakage in Class II composite restoration following amalgam removal

Using the appropriate restoration is essential for a tooth if its structure is lost due to caries or other reasons. Nowadays many people who are concern about esthetics, appeal to replacement of old amalgam fillings with tooth-colored materials.The aim of this study was to evaluate the microleakage of premolar class II composite restoration following amalgam removal.Method and Materials: In this exprimental study thirty Class II cavities were prepared on sound extracted premolars then randomly divided into three groups according to how they were restored. In group 1, light-cured packable composite used as control group; in group 2 first, cavities prepared with a high copper Amalgam then stored in normal saline for 6 months, after that the amalgam was replaced with composite leaving the cavity walls intact. In group 3 identical to group 2, but after removal of 6 months old amalgam restorations, the gingival cavity walls extended a 0.5 mm and then restored with composite. Dye extraction testing was performed for all specimens of these three. Data were analyzed using ANOVA and the Tukey test (α =0.05). There were no significant differences in microleakage between group 3 and group 1(p >0.05). The highest dye absorbance was associated with Group 2 (p<0.05). After amalgam removal, a 0.5 mm extension of the cavity walls could improve the marginal seal of the restorations.