Efficacy of different irrigation and activation systems on the penetration of sodium hypochlorite into simulated lateral canals and up to working length: an in vitro study.

Introduction: The removal of vital and necrotic pulp tissue, microorganisms, and their toxins is essential for endodontic success. However, the complex anatomy of the root canal system has limited our ability to debride it completely. Hence the purpose of this study was to evaluate the effect of currently used irrigation and activation systems on the penetration of sodium hypochlorite into simulated lateral canals and to working length in a closed system.

Methods: One hundred single-rooted teeth were used in this study. A total of 600 simulated lateral canals were created, 6 in each tooth, with 2 lateral canals at 2, 4.5, and 6 mm of working length. To resemble the clinical situation, a closed system was created by coating each root with soft modeling wax. Roots were then randomly assigned to 4 experimental groups: group 1 (n = 20), Endoactivator (sonic activation); group 2 (n = 20), passive ultrasonic (PUI) activation; group 3 (n = 20), F file; group 4 (n = 20), apical negative pressure (ANP) irrigation; and control group 5 (n = 20), positive pressure irrigation. The samples were evaluated by direct observation of the images recorded under the dental operating microscope.

Results: The results demonstrated that the ANP irrigation group was superior at reaching working length, and PUI was the most effective at lateral canal penetration.

Conclusions: The ANP irrigation system demonstrated limited activation of the irrigant into lateral canals but reached the working length significantly more than the other groups tested. In contrast, PUI group demonstrated significantly more penetration of irrigant into lateral canals but not up to the working length.