RESUMEN
Combining the durability of amalgam and the esthetic appearance of composites can improve the quality and longevity of dental restorations. The aim of this study was to evaluate the effect of amalgam etching on microleakage at the cervical margins and the junction between amalgam and composite. In this experimental study 20 extracted sound maxillary premolars were used. Two class II cavities were prepared on the mesial [group A] and distal [group B] surfaces of each tooth. Group A cavities were restored with amalgam on the floor of the cavity and after etching the enamel walls, a self-cure bonding agent was applied followed by composite insertion. The same protocol was followed for group B cavities except that the etchant was placed on both amalgam and enamel walls. The teeth in each group were either stored for 1 week or 6 months in normal saline, then thermocycled for 1000 cycles [2 +/- 4°C and 54 +/- 4°C] and finally immersed in 2% fushin for 1 week. Marginal leakage was assessed by the degree of dye penetration on sections of the restored teeth, under a stereomicroscope [x 10]. Data were analyzed using Mann Whitney U-test [p<0.05]. None of the specimens showed microleakage in the amalgam-composite interface. No statistically significant difference was observed in microleakage between the two groups after 1 week and after 6 months. The study groups did not show a significant difference regarding storage time. Amalgam ethching had no significant effect on the microleakage of combined amalgam-composite restorations