This study aimed to assess the efficacy of canal filling material removal using three different techniques after filling with a Gutta-Percha (GP) cone and calcium silicate-based sealer, by measuring the percentage of volume debris of GP and sealer remaining intracanal with micro computed tomography (micro-CT). The filling material was removed from 30 plastic teeth by a nickel-titanium (Ni-Ti) rotary retreatment system. Final irrigation was performed with 2 mL of saline and 10 specimens were randomly allocated to a conventional group. In the passive ultrasonic irrigation (PUI) group, ultrasonic irrigation was added to the conventional group (n = 10). In the Gentlefile Brush (GF Brush) group, irrigation with GF Brush was added to the conventional group (n = 10). Remaining filling material was measured using micro-CT imaging analysis. The total mean volume of residual filling material after retreatment in the conventional group, PUI group and GF Brush group were 4.84896 mm3, 0.80702 mm3, and 0.05248 mm3, respectively. The percentage of filling material remaining intracanal was 6.76% in the conventional group, 1.12% in the PUI group and 0.07% in the GF Brush group. This study shows that the cleaning effect of the GF Brush system is superior to those of Ni-Ti retreatment files and the PUI system in the apical area.
Keywords: Gentlefile Brush; endodontic retreatment; micro-CT; passive ultrasonic irrigation; root canal retreatment.