مقایسه اثربخشی دو روش مختلف در درمان مجدد کانال های پُر شده با گوتاپرکا و رزیلون

Background: 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. objective: to compare gutta-percha and resilon removal, using protaper rotary files with chloroform or heat in endodontic retreatment.methods: 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.findings: 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).conclusion: 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.