Comparison of apical extrusion of sodium hypochlorite using 3 different root canal irrigation techniques

Introduction: We compared the apical extrusion of sodium hypochlorite delivered with a conventional needle irrigation, passive ultrasonic irrigation and sonically driven system during the irrigation of root canals. Methods: Sixty single-canal teeth were divided into 3 groups. Teeth were embedded in 0.2% agarose gel (pH = 7.4) containing 1 mL 0.1% mCresol purple (titan media), which changes color at a pH level of 9.0. Root canals were irrigated with sodium hypochlorite using 3 different techniques, and the amount of irrigant was controlled. Standardized digital photographs were taken 20 minutes after the first irrigant was used and were analyzed to determine the amount of extrusion (expressed as a percentage of total pixels). Results: The amounts of apical extrusion obtained were 50% (10/20), 40% (8/20), 20% (4/20) for needle irrigation group, passive ultrasonic irrigation and sonically driven system respectively. The sonically driven system and passive ultrasonic irrigation showed significantly lower extrusion values than the needle irrigation techniques in terms of the number of teeth and pixels. Conclusion: The risk of apical extrusion is significantly lower with the sonically driven system and passive ultrasonic irrigation in comparison with the needle irrigation techniques.