Comparative Evaluation of Microleakage of Bulk-Fill and Posterior Composite Resins Using the Incremental Technique and A Liner in Cl Ii Restorations

Background and aim: in recent years there has been a surge in the use of toothcolored restorations. however, the polymerization shrinkage of these materials can form gaps, resulting in microleakage. this study aimed to compare microleakage by using different materials and techniques.materials and methods: in this experimental study, cl ii cavities were prepared on the mesial surfaces of 60 sound human third molars. the teeth were randomly divided into five groups (n=12): group 1 were filled with surefil posterior composite using the oblique incremental technique. in group 2 surefil sdr flowable composite was placed at the base of cavities followed by filling the cavity with surefil posterior composite. specimens in group 3 were restored only with surefil sdr flowable composite resin in two steps, and in group 4, a layer of gaenial universal flow composite with 1 mm thickness was placed as the liner and the rest of the cavity filled with the surefil posterior composite using the oblique incremental technique. group 5 benefited from snow plow technique using gaenial universal flow and surefil posterior composite. samples thermocycled and placed in 0.5% fuchsine solution for 24 hours. the teeth were evaluated under a stereomicroscope for the deepest dye penetration. kruskal-wallis and mann-whitney tests were used for analysis of data.results: the highest frequencies of scores 1 and zero were recorded in the group 5 which indicating the least microleakage in this group. conclusion: g-aenial universal flo composite resin with the snow plow technique resulted in a significant decrease in the microleakage.