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Open Access

Open Access


The use of irrigation as a method of rendering canals bacteria free continues to be a source of investigation. Recent data suggests that an activated irrigation protocol such as passive ultrasonic irrigation can result in decreased intracanal bacteria. In addition, studies have shown that the activation of various irrigants such as NaOCl and Chlorhexidine can increase the sum antimicrobial effect. The purpose of this randomized, double blinded, prospective in-vivo clinical study was to compare the results of a non-activated irrigation protocol (NAI) using only NaOCl 1.5% to a passive ultrasonic irrigation protocol (PUI) using NaOCl 1.5%, EDTA 17% and Chlorhexidine 2% in rendering canals bacteria free. Forty-Four patients were recruited with a posterior tooth requiring primary endodontic treatment of a necrotic pulp, diagnosed by negative cold test and periapical radiolucency. Standard non-surgical endodontic therapy was performed on both groups using micro-tip irrigation syringes. After completion of instrumentation, teeth were randomly treated with NAI or PUI. Bacterial cultures were obtained from the canals prior to instrumentation and after irrigation protocol. These cultures were evaluated for growth after 7 days in enriched anaerobic medium. Statistical analysis was performed on data using the Fisher’s exact test. NAI and PUI rendered canals bacteria free 80% and 84%, respectively. This difference was not significant (p=0.23). We conclude that although there was no statistical difference between irrigation methods both protocols resulted in a high frequency of negative cultures and this is most likely related to increased volume and depth of irrigation.