The purpose of this study was to evaluate the Thermafil endodontic obturation technique. Extracted single-tooted teeth were treated by the step-back technique. The root canal were obtured by gutta-percha points containing a central plastic carrier, Ketac Endo was used as a sealer. The filled root canals were cut transversally, and the quality of the obturation was investigated in the apical, middle and coronal thirtds respectively. Five tooth were cut longitudinally. All samples were routinely preparred for SEM investigation. The results of the study in SEM indicated that the apical third of the root canal was obtured totally. Thermafil gutta-percha points penetrated into accessory canals, ramifications and into the orifices of dentine tubules.

        Key words: Thermafil – Ketac Endo – SEM