Comparative evaluation of efficacy of three different retreatment regimens in gutta-percha removal with and without chloroform – an in vitro study

Background: A growing interest in endodontic retreatment has been seen recently to preserve teeth where endodontic therapy has failed. Effective removal of gutta-percha in endodontic retreatment is a significant factor to ensure a favorable outcome from failed procedures. Objective: To compare the efficacy of two nickel-titanium rotary retreatment systems versus stainless steel hand files for gutta-percha removal with or without solvent. Materials and Methods: Ninety freshly extracted human mandibular premolar teeth were prepared and filled. They were divided into 6 groups according to the type of retreatment regimen used: Gates-Glidden and H-files, Gates-Glidden and H-files with chloroform, ProTaper Universal rotary retreatment system, and ProTaper Universal rotary retreatment system with chloroform, MTwo R rotary system and MTwo R rotary system with chloroform. The teeth were longitudinally sectioned and photographed. The images were analyzed under stereomicroscope and the filling remnants were quantified by using the IMAGE TOOL 3.0 software. ANOVA and unpaired ‘t’ test were used for analysis. Results: A significant difference between the rotary retreatment files and hand files in regard to the amount of the endodontic filling remnants (p>.05) was seen. Conclusion: All of the techniques proved helpful for the removal of endodontic filling material, but MTwo R rotary system without chloroform left cleaner canals as compared to other techniques.