https://www.selleckchem.com/products/z-lehd-fmk-s7313.html The aim of this study was to compare smear layer removal by conventional application (CA), passive ultrasonic irrigation (PUI), EasyClean (EC), and XP-Endo Finisher (XPF), using 17% ethylenediaminetetraacetic acid (EDTA) after chemomechanical preparation, as evaluated with scanning electron microscopy (SEM). Forty-five single-rooted human mandibular premolars were selected for this study. After chemomechanical preparation, the teeth were randomly divided into 5 groups according to the protocol for smear layer removal, as follows G1 (control) CA of distilled water; G2 (CA) CA of 17% EDTA; G3 (PUI) 17% EDTA activated by PUI; G4 (EC) 17% EDTA activated by EC; and G5 (XPF) 17% EDTA activated by XPF. SEM images (×1,000) were obtained from each root third and scored by 3 examiners. Data were evaluated using the Kruskal-Wallis and Dunn tests ( < 0.05). In the apical third, there were no statistically significant differences among the groups ( > 0.05). In the cervical and middle thirds, the experimental groups performed better than the control group ( < 0.05); however, G2 presented better results than G3, G4, and G5 ( < 0.05), which showed no differences among one another ( > 0.05). No irrigation method was able to completely remove the smear layer, especially in the apical third. Using CA for the chelating solution performed better than any form of activation. No irrigation method was able to completely remove the smear layer, especially in the apical third. Using CA for the chelating solution performed better than any form of activation.Root canal debridement, which includes the removal of infected tissues and microbial biofilms, is considered the corner stone of root canal treatment. Chemical adjuncts play a multitude of functions in this regard, as tissue solvents, antimicrobial agents and for removing the smear layer. These adjuncts (irrigants) are usually delivered using a syringe and needle. With increasing k