Aim of the study:The aim of this study was to evaluate the efficacy of protaper universal retreatment files , R endo files and Mtwo retreatment files in removal of gutta percha from root canal during retreatment. And also to compare time taken by this instruments for removing gutta percha from root canal. Methodology: Thirty single rooted anterior and premolar teeth were selected. After disinfection of samples, crowns were decoronated to obtain uniform root sections of 15mm for all samples. The root canals were accessed and preparation was carried out using Protaper NiTi rotary system and obturation was done by cold lateral condensation. The obturated specimens were randomly divide into 3 groups with each group containing 10 samples. Obturation material in each group were removed with Protaper Universal Retreatment system (PTUR), R endo and Mtwo retreatment files respectively. Operating time was measured during procedure using timer .Post-operatively Cone Beam Computed Tomography (CBCT) was used to assess the percentage of residual filling material in the root canals. The results were evaluated statistically using One Way Anova and Post Hoc Tukey tests Results: PTUR and Mtwo files took significantly less time for gutta-percha removal than R-Endo files. R endo files showed significantly lower amount of remaining obturation material compared to PTUR and Mtwo. When compared to PTUR , Mtwo have less efficacy in removing gutta percha . Conclusion: Within the limitations of this study,it was revealed that R endo files showed better retreatment efficacy than PTUR and Mtwo. R-Endo files required more time to remove root filling material than PTUR and Mtwo files. Complete removal of materials did not occur with any of the instrument systems investigated.
