Background: Instrumentation and irrigation of the root canal facilitating effective debridement is considered the most important single factor in the prevention and treatment of endodontic diseases. Aim: The aim of the study was to evaluate the depth of penetration of the irrigant depending on the final activation using Waterpik device modified with NaviTip needle, passive irrigation, and manual dynamic activation using the radiopaque solution in conjunction with digital dental radiography. Materials and Methods: Ninety freshly extracted single-rooted mandibular premolars based on the inclusion and exclusion criteria were used for this study. Access cavity preparation was done for all the samples, and the working length of each sample was determined using a size 10-k file. The radiopaque solution (Urografin) was delivered into (Groups A, B, and C) prepared canal of samples at the rate of 1 ml in 30 s with up-and-down motion. Results: The test results showed that Waterpik WP-100 group showed significantly high infiltration index values as compared to passive irrigation and manual irrigation group at P < 0.002 and P = 0.007, respectively. Conclusion: Sonic irrigation using a Waterpik device modified with a NaviTip needle permits better infiltration of the irrigant.