Aim: This study used micro-computed tomography (CT) to compare the efficacy of three techniques for removing the root canal filling in single oval-shaped root canals after using laterally compacted gutta-percha/bioceramic sealer (BCS). Materials and Methods: Root canals in 30 single-rooted teeth will be instrumented with the ProTaper NEXT (Dentsply Maillefer, Ballaigues, Switzerland) and obturated using lateral condensation technique with gutta-percha and BCS. The teeth were divided randomly into three groups (n = 10). Removal of the root fillings was performed using one of the following techniques: group 1: ProTaper Universal Retreatment System with continuous rotational motion (RM); Group 2: Reciproc files with reciprocating adaptive motion; and Group 3: retreatment was done using Gates Glidden (GG) drills and H files. The teeth were scanned with CT scans. The percentage of remaining filling material was recorded. The data were analyzed statistically using the one-way ANOVA test and Tukey's post hoc test. Two-way ANOVA was used to study the effect of the interaction of file type and root segment, at a 95% confidence level (P