Effectiveness of Final Irrigant Protocols for Debris Removal from Simulated Canal Irregularities

• An association was observed among the debris scores and protocols that used passive ultrasonic irrigation (PUI).
• In groups that used PUI, the frequency of scores 1 and 2 was higher than expected.
• The frequency of score 4 was lower than expected in groups that used PUI.
• No association was found among the scores of debris removal and the irrigants.

IntroductionThe aim of this in vitro study was to compare the effectiveness of saline, 2.5% sodium hypochlorite, and 2% chlorhexidine, with or without passive ultrasonic irrigation (PUI), in debris removal from simulated canal irregularities within prepared root canals.MethodsNinety bovine lateral incisors were randomly divided into 3 main groups (n = 30) based on the irrigant and prepared with hand files attached to an oscillating handpiece (NSK, Tokyo, Japan) up to a size #80 K-file. Next, the teeth were split longitudinally, and a standardized groove was prepared into the apical third and filled with dentin debris. After the halves were reassembled, they were placed in a muffle. Each main group was randomly subdivided into 2 groups (n = 14) and was treated with different final irrigation protocols. In the sodium hypochlorite/PUI, chlorhexidine/PUI, and saline/PUI groups, the solution was ultrasonically activated 3 times for 20 seconds. In the remaining groups, PUI was not performed. Specimens were scored for debris removal and analyzed under a scanning electron microscope.ResultsAn association was observed between the score of debris removal and protocols using PUI (P < .05). No association was observed between the scores of debris removal and the irrigants (P = .87).ConclusionsFinal irrigation protocols that used PUI were more effective in removing debris from simulated canal irregularities into the apical third than those that did not use it.