Summary. The aim of the present microtomographic study was to investigate the quality of root canal filling and the voids formation in canals of extracted teeth instrumented with a simultaneous technique and filled with two different methods. Twenty-four single-rooted teeth were assigned to two experimental groups (no. = 12); canals were shaped with NiTi rotary files, irrigated with NaOCl and filled either with the single point (group 1) or the continuous wave of condensation technique (group 2). Specimens under- went microtomographic scanning. Collected data were statistically analyzed by nonparametric methods. Void mean percentages were found to be limited and similar between the two groups; the single point technique led to greater sealer thickness in partially oval canals.