Iranian Dental Association Journal of Iranian Dental Association 3060-8201 30 1 2018 01 01 Comparative Evaluation of microleakage of Bulk-fill and Posterior Composite Resins Using the Incremental Technique and a Liner in Cl II Restorations 1 8 10.30699/JIsdreir.30.1.01 EN Samaneh Doustfateme Kazem Khosravi Somayeh Hosseini Journal Article 10.30699/JIsdreir.30.1.01 2018 04 30 2018 04 30 Background and Aim: In recent years there has been a surge in the use of tooth-colored 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.<br> 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 G-aenial 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. Group5 benefited from snow plow technique using G-aenial 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.<br> Results: The highest frequencies of scores 1 and zero were recorded in the group 5 which indicating the least microleakage in this group.<br> Conclusion: G-aenial Universal Flo composite resin with the snow plow technique resulted in a significant decrease in the microleakage.