Introduction and Aim: The basis of an effective root canal treatment lies upon extensive debridement, thorough removal of smear layer and attaining a three–dimensional hermetic seal. The aim of the study was to assess radiographically the penetration depth of irrigantin root canals with three irrigation modalities: Conventional syringe, Side vented needle and Endoactivator.

Materials and Methods: Twenty–eight single rooted anterior teeth were used for study. Cleaning of teeth was done to remove superficial debris. Access openingswere performed and determination of working length was done. Instrumentation was done with MTwo rotary files upto# 20 0.06% taper. Intermittent copious irrigation was carried out with 3%NaOCl (Septodont) and 17% EDTA. Samples were assigned randomly to experimental (Side vented needle and Endoactivator) groups and a control(Conventional syringe) group. Radiopaque contrast agent Iohexol was added to Sodium hypochlorite to visualise irrigantpenetration inside the root canals during final rinse. Digital radiographs were secured for bothexperimental and control groups and radiographic analysis was performed.

Results: Sonic activation in the form of Endoactivator resulted in maximum irrigant penetration in root canals followed by Side vented needle.  Minimum irrigant penetration is shown by Conventional syringe.

Conclusion: The irrigant penetration in root canalsis enhanced by sonic activation allowing its spread in lateral and accessory canals henceresulting towards better treatment outcomes.