Effectiveness of different irrigation systems in the presence of intracanal-separated file.

The aim of this study was to evaluate conventional syringe irrigation and three different irrigant activation techniques' effectiveness for smear layer removal in the absence and presence of intracanal-separated file (SF) fragment. Mandibular anterior teeth (160 total) with single canal were used and each root canal preparation was finished with the ProTaper Universal F1. The samples were randomly divided into eight equal groups with n = 20 in each group. The Protaper Universal F3 file was used to simulate intracanal file separation in four groups. To remove the smear layer, final irrigation for each group was performed with conventional syringe irrigation (CSI), EndoActivator, Vibringe, and passive ultrasonic irrigation (PUI). The roots were divided into two longitudinal parts and evaluated with scanning electron microscopy, and two observers scored smear layers at 1, 2, and 3 mm away from the minor foramen. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (p < .05). PUI significantly removed the smear layer better at all levels than other nonseparated file groups (p < .05). In the presence of intracanal SF, PUI had the most efficiency loss. Sonic techniques and CSI revealed statistically better smear layer removal efficiency than PUI at 3 mm level in the presence of SF (p < .05). The intragroup score analysis at all levels revealed that there were less smear layers at 3 mm than at 1 mm in all SF groups (p < .001). As a conclusion, sonic/ultrasonic methods did not yield better irrigant by-passing than CSI in the presence of intracanal SF.