RESUMEN
Background: The complete removal of residual filling materials from the root canal determines the success of root canal retreatment. Aim: To evaluate and correlate the efficacy of ProTaper retreatment system, R-Endo retreatment system, and Hedstrom file in the removal of gutta-percha and sealer from root canal during endodontic retreatment in addition to the period desired for the elimination of gutta-percha and sealer. Methodology: Thirty extracted premolars were prepared and filled by cold lateral compaction with gutta-percha and sealer. Retreatment was finished with ProTaper retreatment files, R-Endo files, Hedstrom files with Endosolv E as the solvent for 10 specimens each. Each half of the root was imaged using the image analyzer software Chroma allied to a stereomicroscope with 10× magnification via a charge-coupled device sensor. For statistical analysis, parametric one-way ANOVA test and Scheffe post hoc multiple range test were utilized at a significance level of P < 0.05. Results: There is no significant difference among the three groups at P < 0.0001 in removing filling material. However, the rotary files needed significantly less time for removing gutta-percha along with sealer than H-file (P < 0.0001). Conclusion: The gutta-percha and sealer were found in the root canal subsequent to all the retreatment techniques, especially in the apical third. Retreatment time was less only for the rotary system.