Efficacy of retreatment rotary files in removing obturation material with different sealer from the root canal system: a micro-computed tomography study

Aim To evaluate efficacy of XP-3D and TRUShape rotary retreatment system for gutta-percha (GP) removal from root canals. Methodology Root canals of 40 extracted human single rooted teeth were prepared with ProTaper gold rotary system and obturated with hydraulic condensation technique with BC sealer (n=20) or multiple wave technique with ZOE sealer (n=20). Teeth were evaluated with Micro CT and then divided into four groups and in all groups, GP first removed with Gates Glidden drills and patency achieved by K stainless steel files (Kerr) files with chloroform as a solvent. Further canal repreparation accomplished: group A (n=10, BC sealer/hydraulic condensation technique) – GP removal with the XP-3D shaper and finisher; group B (n=10, BC sealer/hydraulic condensation technique) –GP removal with the TRUshape; group C (n=10, ZOE sealer/multiple wave technique) – GP removal with the XP-3D shaper and finisher; group D (n=10, ZOE sealer/multiple wave technique) – GP removal with the TRUshape. Operating time was recorded. Teeth were evaluated with micro-CT of the area of remaining GP/sealer in bucco-lingual and mesial–distal directions. Two-way ANOVA Statistical analysis was performed. Results There was a statistically significant difference among the groups regarding sealer removal (P<0.05), the retreatment of samples with ZOE was more effective than BC Sealer. No significant difference was observed between retreatment rotary systems of group C and D (ZOE Sealers). The volume of remaining obturation material was significantly less in group B than group A (BC Sealers). Mean operating time for group A was 6.71 min, which was significantly higher (P