Introduction: The complex anatomy of the root canal system has been shown to limit the penetration of irrigating solutions into the apical third; hence, the aim of this study was to determine whether the use of a patency file is related to the presence of a radiopaque irrigating solution in the apical third of human root canals after using passive ultrasonic activation in vivo.
Methods: Forty human root canals were randomly divided into two groups. Apical patency was maintained in one group (n = 21) during shaping and cleaning procedures with a no. 10 K-file 1 mm beyond the working length (WL) but not in the other group (n = 19). In both groups, the canals were shaped with the Pro Taper system (Dentsply-Maillefer, Ballaigues, Switzerland). Irrigation was performed with 1 mL of a solution prepared with a radiopaque contrast medium and sodium hypochlorite 5.25%, and then passive ultrasonic irrigation (PUI) was applied after the shaping procedure. Digital images were taken, and a calibrated reader determined the presence or absence of the irrigating solution in the apical third.
Results: There were significantly more canals with irrigant in the apical third after PUI when apical patency was maintained with a no. 10 file 1 mm beyond the WL than when apical patency was not maintained throughout the cleaning and shaping procedures (P = .02).
Conclusions: Maintaining apical patency and then using PUI improves the delivery of irrigants into the apical third of human root canals.
Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.