In vitro evaluation of the cleansing working time and analysis of the amount of gutta-percha or Resilon remnants in the root canal walls after instrumentation for endodontic retreatment.

The present study assessed the obturation removal and reinstrumentation working time of canals filled with Resilon/Real Seal in comparison with canals filled with gutta-percha/AH Plus. Thirty human extracted canines were instrumented. In group 1 (n = 15) root canals were filled with Resilon/Real Seal and in group 2 (n = 15) with gutta-percha/AH Plus sealer. The obturations were removed from both by using chloroform and irrigation with 2.5% NaOCl, and the canals were manually reinstrumented. The teeth were radiographically analyzed. Specimens without obturation material remnants visible in the radiographic examination were selected for analysis under scanning electron microscopy. The Resilon/Real Seal system was removed in greater quantities from the canal walls compared with the gutta-percha cones and the AH Plus cement. Time was not a significant factor. Under scanning electron microscopy analysis, the teeth presented material remnants in the 3 analyzed thirds. Resilon was better removed from the canal than the gutta-percha cones and the AH Plus.