text: Comparative Evaluation of the Efficiency of Manual and Rotary Gutta-percha Removal Techniques.
  This study aimed to evaluate the efficiency of 2 manual and 2 rotary gutta-percha (GP) removal techniques in terms of both the total operating time and GP remnants left in the canal. GP was removed with manual techniques using H-files and xylene (H + X) and H-files and System B (H + SB) (SybronEndo, Orange, CA) and with rotary techniques using the ProTaper Univeral Retreatment (PTUR) (Dentsply Maillefer, Ballaigues, Switzerland) and D-RaCe Retreatment (D-RR) (FKG Dentaire, La Chaux-de-Fonds, Switzerland) systems. The total operating time was evaluated as the time taken to reach the working length and completely remove GP until no radiopaque remnants were observed in the final radiograph. Any GP remnants left in the canal were evaluated in terms of percentage in the whole canal. Rotary techniques were significantly faster and left lesser GP remnants than manual techniques (P < .05). In rotary techniques, the D-RR system was significantly faster than the PTUR system (P < .05), but there was no significant difference between them regarding GP remnants (P > .05). In manual techniques, H + X was significantly faster and left lesser GP remnants than H + SB (P < .05). Rotary techniques were more efficient than manual techniques in GP removal. Overall, the D-RaCe Retreatment system was most efficient, whereas manual use of H-files with System B was least efficient. However, because all the techniques showed GP remnants in the canal and radiographs failed to show these remnants, additional measures would be required to ensure complete GP removal and check for cleaner canals during endodontic retreatment.