Comparing the effectiveness of Gutta-Percha and Resilon removal using two different techniques in endodontic retreatment

The goal of nonsurgical retreatment is the removal of all filling materials to completely disinfect the whole root canal space. Recently Resilon obturating system has been introduced as a root canal filling material. To compare Gutta-percha and Resilon removal، using ProTaper rotary files with chloroform or heat in endodontic retreatment. This experimental study was performed on sixty-four human single-canal lower jaw extracted premolars at Dental School، Qazvin University of Medical Sciences during 2010. Following separating teeth crowns from the cementoenamel junction، canals were instrumented using step-back technique with k-files. Later، the extracted teeth were randomly divided into four groups of 16 teeth. Canals were obturated with either gutta-percha/AH26 (groups 1،2) or Resilon/Epiphany (groups 3،4). Retreatment for groups 1 and 3 was performed with ProTaper system and heat and for groups 2 and 4 with ProTaper system and chloroform using crown-down technique. Once the retreatment procedure was completed and justified، roots were sectioned longitudinally and examined under stereomicroscope. Data were analyzed using T-test، Kruskal-Wallis، and Mann-Whitney tests. In all groups، some filling materials (core material and sealer) were seen on the canal walls. Although، amount of Gutta-Percha/AH26 and Resilon/Epiphany system residue were similar، the amount of residual materials in group 4 was significantly more than other groups (P<0. 05). Furthermore، the amount of residual materials in group 3 was more than group 1 in the coronal third of canals (P<0. 05). The time required to remove filling material in group 2 was significantly higher than those of other groups (P<0. 05). According to our findings، Resilon، like Gutta-percha، is re-treatable. However، none of these two materials could be completely removed from root canal walls.