Effectiveness of Erbium: Yttrium–Aluminum–Garnet laser with side-firing spiral EndoTip and ethylenediaminetetraacetic acid on smear layer removal: A scanning electron microscopic study

Abstract Background: Successful endodontic therapy depends on effective smear layer removal to ensure optimal disinfection and sealing of the root canal system. Chelating agents such as Ethylenediaminetetraacetic acid (EDTA) are routinely used; however, their ability to clean the apical third remains limited. Laser-assisted irrigation has been proposed as an adjunct to enhance smear layer removal. Aim: This study aims to evaluate and compare the effectiveness of 17% EDTA, Erbium: Yttrium–Aluminum–Garnet (Er: YAG) laser (side-firing spiral EndoTip), and their combination in removing the smear layer from root canal dentin. Materials and Methods: Forty extracted single-rooted premolars were instrumented using ProTaper Universal rotary files and randomly divided into four groups ( n = 10) based on the final irrigation protocol: (1) Group 1: Distilled water (control), (2) Group 2: 17% EDTA, (3) Group 3: Er: YAG laser irradiation, (4) Group 4: EDTA with Er: YAG laser-activated irrigation. Longitudinally sectioned samples were examined under a scanning electron microscope at the coronal, middle, and apical thirds. Smear layer removal was assessed using Hülsmann’s scoring criteria. Statistical Analysis: Data were analyzed using SPSS version 21.0. Intergroup comparisons were performed using the Chi-square test, with P < 0.05 considered statistically significant. Results: The combination of EDTA and Er: YAG laser-activated irrigation demonstrated the most effective smear layer removal across all root canal levels, followed by laser alone, EDTA, and the control group ( P = 0.001). Conclusion: Er: YAG laser activation combined with 17% EDTA significantly improves smear layer removal and enhances overall root canal cleanliness compared to conventional irrigation methods.