Abstract
Background:
Effective root canal disinfection remains a major challenge in endodontic therapy because of the complex anatomy of the root canal system and the persistence of microorganisms within inaccessible areas. Various irrigation activation techniques, including manual dynamic agitation, sonic irrigation, and ultrasonic irrigation, have been developed to improve smear layer removal and antibacterial efficacy. This systematic review aimed to compare the effectiveness of these irrigation activation methods in enhancing root canal cleanliness and reducing bacterial load.
Methods:
A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, and Google Scholar from inception until May 2026. Studies comparing at least two irrigation techniques, including manual, sonic, ultrasonic, or conventional syringe irrigation, were included. Primary outcomes assessed were smear layer removal, debris elimination, and bacterial reduction. Quality assessment was performed using the Cochrane Risk of Bias 2 tool for randomized clinical trials and the Joanna Briggs Institute checklist for ex vivo studies.
Results:
A total of 2,184 studies were identified, of which six met the eligibility criteria. These included two randomized clinical trials and four ex vivo studies. Activated irrigation systems consistently demonstrated superior performance compared with conventional syringe irrigation. Sonic irrigation showed effective smear layer removal, particularly in the apical third, while passive ultrasonic irrigation demonstrated greater dentinal tubule cleanliness and superior antibacterial efficacy. Clinical studies also reported greater bacterial reduction and reduced postoperative pain with ultrasonic activation.
Conclusion:
Sonic and ultrasonic irrigation activation techniques demonstrated superior effectiveness in smear layer removal and bacterial reduction compared with conventional irrigation methods. Incorporating activated irrigation systems into routine endodontic practice may improve root canal disinfection and treatment outcomes. Further well-designed randomized clinical trials are required to establish standardized clinical protocols