Objective: The study intended to assess the amount of the apical-debris extruded using two different file kinematics during the retreatment procedure on mandibular premolars.
Methodology: A total number of 40 extracted single mandibular premolars (single root -single canal) were disinfected by sodium hypochlorite, and decoronated to attain a length of 19 mm for each tooth to ensure standardization. Root canal treatment was done to all roots then, roots were kept for 1 week at 100% humidity and 37 °C to allow for proper setting of sealer. Teeth were coded and randomly assigned into two groups corresponding to the technique of retreatment; group I: Mtwo Retreatment files and group II: Reciproc 25 single file. Extruded debris was collected in Eppendorf tubes which were then weighed after incubation for 15 days at 370C. The time required for removal of gutta-percha was recorded.
Results: For assessment of the amount of debris extruded following retreatment, results showed insignificant difference between the tested groups at p=0.470. For time of preparation, group I (M Two) showed more time consuming compared to group II (Reciproc) at p=0.023.
Conclusion: Both Reciproc and Mtwo retreatment system were efficient in retreatment procedure. Both systems resulted in extrusion of debris with no significant difference between them. While the Reciproc significantly shortened the time of preparation compared to the Mtwo system.