Introduction: The purpose of this study was to evaluate and compare the adaptability of TotalFill, Mineral trioxide aggregate (MTA) and Intermediate restorative material (IRM) on human extracted teeth. Methods: Thirty single rooted freshly extracted human teeth with mature apices were selected. Clinical crowns were sectioned at the cement-enamel junction to create a standardized length of about 16 mm. The root canals were instrumented in a crown down technique by using Protaper rotary nickel titanium files. Root canals were obturated with Gutta-percha and resin based sealer. The root-ends were then resected perpendicular to the long axes of the teeth and ultrasonically prepared to receive a retrofilling. Under scanning electron microscopy, the gaps between the material and dentinal wall were measured. Results: The maximum mean gap measurements were found in IRM, whereas the minimum mean gap measurements were found in TotalFill. Conclusion: None of the tested materials had a perfect marginal adaptation to the walls of the prepared retro cavity.