FESEM evaluation of smear layer removal using different irrigant activation methods (EndoActivator, EndoVac, PUI and LAI). An in vitro study.

Objectives: This study was to compare the efficacy of EndoActivator, EndoVac, PUI, and LAI methods in removing the smear layer from root canals.

Materials And Methods: Eighty single-rooted mandibular premolars were decoronated to a standardized length of 15 mm. Specimens were shaped to ProTaper F4 (Dentsply Maillefer) and irrigated with 5.25% NaOCl at 37 °C. Teeth were divided into six groups (two control groups [n = 10] and four test groups [n = 15]) according to the final irrigation activation/delivering technique (sonic irrigation [EndoActivator], passive ultrasonic irrigation [PUI], negative apical pressure [EndoVac], and laser activated irrigation [LAI]). Root canals were then split longitudinally and observed with field emission scanning electron microscopy to evaluate the presence of smear layer at 1, 3, 5, and 8 mm from the apex. Scores were analyzed by Kruskal-Wallis and Mann-Whitney U tests.

Results: The EndoActivator was significantly more efficient than PUI, LAI, and control groups in removing the smear layer at 3, 5, and 8 mm from the apex. The EndoVac System removed statistically significantly more smear layer than all groups at 1 mm from the apex. At 5 mm from the apex, EndoActivator and EndoVac removed more smear layer than LAI and control groups. At 5 and 8 mm from the apex, PUI and EndoVac did not differ statistically, but both performed statistically better than the control groups.

Conclusion: In our study, none of the activation/delivery systems completely removed the smear layer from the root canal walls; nevertheless, EV and EA showed, respectively, statistically significant better results at 1, 3, 5, and 8 mm and 3, 5, and 8 mm from the apex.