Removal of smear layer by two endodontic irrigation solutions and erbium: yttrium, aluminum, garnet [Er:YAG] laser: a scanning electron microscope [SEM] study

ABSTRACT

The purpose of the present study was to determine the effect of 17% Ethylene, di-amine, tetra-acetic acid [EDTA], 6% phosphoric acid and Erbium Yttrium, Aluminum, Garnet [ErYAG] Laser in removing the smear layer by scanning electron microscopy. In this study, 80 single-rooted human teeth were selected. Instrumentation was done by use of hand files and step-back technique up to file #40 at apical and file #80 at coronal area. During instrumentation, 1ml of 5.25% sodium hypochlorite [NaOCl] was used as irrigation between each file. The teeth were randomly divided into four groups with different methods of smear removal.17% Ethylene, di-amine, tetra-acetic acid was used in group 1, 6% Phosphoric acid in group 2, Erbium Yttrium, Aluminum, Garnet laser in group 3, and no intervention in group 4 [as control]. Roots were then longitudinally sectioned and prepared for scanning electron micrograph in cervical, middle and apical areas. Data were analyzed by Kruskal-Walis, Mann-Whitney, Friedman and Wilcoxson tests [P<0.05]. The results showed a significant difference in smear layer removal between three methods in favor of the EDTA [P<0.001] and Phosphoric groups [P<0.001] with no significant difference between them [P=0.49]. Although ErYAG laser showed some limited ability to remove the smear layer, the effectiveness was not significantly different from the control group [P=0.157]. Based on the findings of this study, EDTA and Phosphoric acid were effective methods to remove smear layer from the root canal walls but ErYAG laser showed less efficacy compared to the other experimental groups