Effect of Different Base Materials and Techniques on Microleakage in Class II Composite Open Sandwich Restorations

Aims: This study was performed to compare microleakage in class II composite restorations with flowable composites and dual cure composite resin as intermediate material and also to evaluate the effect of delayed light polymerization of dual cure composite base on microleakage. Materials and methods: Class II box cavities were made with air water spray and divided into four groups. Group 1 was restored without base, group II with flowable composite base, group III with a dual cure composite base which was immediately cured and group IV with 60 seconds delayed cure, dual cure com posite base. Remaining cavity was restored with composite resin Specimens were immersed in methylene blue dye after thermo cycling and sectioned through mesiodistal center of tooth and observed for leakage pattern. Microleakage was evaluated using dye penetration with methylene blue. Microleakage pattern was observed under a stereomicroscope. Kruskal-Wallis test and Mann-Whitney test were used for statistical analysis. Results: Results of the study showed that application of a composite resin base below a class II composite restoration significantly decreased microleakage as compared to restorations without a base. The least and comparable microleakage scores were seen in groups with flowable composite and dual cure composite (delayed cure) as a base, followed by dual cure composite which was immediately cured.