Results of the two examiners were in good agreement (kappa value=0.897). Comparisons between the groups are presented in Tables 1 and 2. Elimination of CH was more difficult from the apical region. None of the irrigation protocols could completely remove all remnant of CH in all three root regions. Beveled needle irrigation (Group 1) and double side-vented needle irrigation (Group 2) were the significantly least efficient on the elimination of CH from the grooves (P<.001). PUI (Group 6) and Er:YAG laser-activated irrigation (Group 7) removed more CH than the other protocols in all thirds of the root; however, no significant differences were found between these two groups (P>.05). No significant differences were found between XP-endo Finisher (Group 4) and PUI (Group 6) at the coronal and middle regions (P>.05). The Kruskal-Wallis test showed significant differences between the groups for coronal, middle, and apical thirds (P<.05), except for the CanalBrush (Group 3) (P>.05).