Aim: Our study was conducted to assess the efficacy of three rotary nickel-titanium retreatment systems in terms of remaining obturation material on canal walls, debris extruded out of the canal, time taken to reach full working length and number of fractured files in each system.
Methodology: 120 canals (type III) in 60 mesial roots of lower mandibular first molars were randomly divided into 3 groups of 40 canals each according to the retreatment system used. In Group (I) retreatment was done using Protaper universal retreatment file system (PTUR), Group (II) Mpro retreatment file system was used and Group (III) RT gold file system.
Results: Protaper universal retreatment system showed to be significantly more effective in removal of root canal filling material, consumed less time during retreatment with less number of fractured instruments. While Mpro retreatment files showed the least amount of apically extruded debris.
Conclusion: Under the circumstances of this study, it can be concluded that all techniques failed to clear the canals from remaining obturating material with the highest percentage on the apical area, debris extrusion remains problematic in all systems used, Protaper file is the most speed efficient and has higher efficacy in removal of root canal filling material than the other two groups.