Purpose: ‏ This study was designed to compare the coronal micro-leakage of resin modified glass ionomer (RMGI) and Smart Dentin Replacement (SDR) as intra orifice barrier using two different obturation techniques.
Material and methods: 16 freshly extracted human mandibular premolars were used in this study. They were decapitated to make length in all teeth =16. Teeth were divided into 2 equal groups (n=8) according to the obturation technique: group (L): lateral condensation, group (S): single cone. Rotary files (Mpro system) were used to prepare the root canals, which were then filled with gutta-percha and resin sealer. Three millimeters of the gutta-percha had been removed from the root canals then each group was sub divided into four experimental groups according to intra-orifice materials into SDR and RMGI and two control groups. All teeth were immersed in methylene blue for one week then sectioned longitudinally parallel to their long axis. A stereomicroscope with a 10X magnification was used to examine the samples in order to determine the dye penetration.
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Results: The mean dye penetration depth values were significantly different between the materials for lateral condensation technique and single cone technique. Mean dye penetration depth in all the groups were significantly different from each other with the lowest dye penetration depth values in negative control groups followed by SDR and RMGI and the highest in positive control group.
Conclusion: SDR and RMGI used as an intra-orifice barriers placement gives accepted coronal seal, prevents micro-leakage, and enhances the durability of post obturation restorations.