Effect of EDTA, Sonic, and Ultrasonic Activation on the Penetration of Sodium Hypochlorite into Simulated Lateral Canals: An In Vitro Study

Introduction: The purpose of this study was to evaluate the penetration of 5.25% sodium hypochlorite alone or in combination with 17% EDTA in simulated lateral canals using sonic and ultrasonic activation. Methods: Four hundred and eighty simulated lateral canals were created in 80 single rooted cleared teeth by inserting 06 K-files at 2, 4.5 and 6 mm of working length. Samples were mounted on clear silicon to simulate the presence of surrounding periodontal tissues and its effects on fluid dynamics and then randomly assigned to four experimental groups: 1 (n = 20) 5.25% NaOCl + sonic activation; 2 (n = 20) 5.25% NaOCl + ultrasonic activation; 3 (n = 20) 5.25% NaOCl + 17% EDTA + sonic activation and 4 (n = 20) 5.25% NaOCl + 17% EDTA + ultrasonic activation. Sonic activation was delivered using the Endoactivator (R) inserted 2 mm short of working length and activated for 1 minute. Ultrasonic activation was performed with a stainless steel ultrasonic file inserted 2 mm short of working length and passively activated for 3 cycles of 20 seconds each. Samples were evaluated by direct observation of the images recorded under the operating microscope and by radiographic evaluation after irrigation with a contrast solution. Results: Sonic and ultrasonic activation resulted in a better irrigation of the lateral canals at 4.5 and 2 mm from working length compared to traditional needle irrigation alone. Traditional needle irrigation alone demonstrated significantly less penetration of irrigant into the lateral canals and was limited to the level of penetration of the needle. Conclusion: The addition of EDTA did not result in better penetration of irrigants into the lateral canals. (J Endod 2009;35:891-895)