Aim and objective: To compare the effectiveness of erbium:yttrium–aluminum–garnet laser, GentleWave irradiation, photodynamic therapy (PDT), and sodium hypochlorite in smear layer removal and dentin permeability with a scanning electron microscope (SEM). Materials and methods: Seventy-five recently extracted single-rooted teeth (maxillary second premolars) were randomly divided into 5 groups of 15 each. Group I teeth was the control group in which conventional root canal preparation (RCP) [17% ethylenediaminetetraacetic acid (EDTA)] was done without laser irradiation, group II teeth underwent RCP and GentleWave™ treatment, group III teeth were subjected to Er:YAG laser irradiation, group IV uses low-level 660 nm (PDT), and group V samples were irrigated with 5.25% NaOCl. All samples were viewed under the SEM. Images at the coronal, middle, and apical part of the root canal were obtained at ×1000. A scoring system for smear layer removal and debris removal scoring was used for analysis. Results: Smear layer removal was significantly higher at different points (coronal, middle, and apical area) in group I, followed by V, IV, II, and group III in declining order (p < 0.05). Intercomparison between the groups at different points indicates a significant difference in smear layer removal score between group I and group V at coronal, middle, and apical third. The result was not significant at coronal third and middle third, between group I and V, II and III, II and IV. The result was not significant at apical third between I and V, II and III, and II and IV (p < 0.05). Ethylenediaminetetraacetic acid and sodium hypochlorite are effective in smear layer removal followed by the Er-YAG laser technique. Conclusion: Ethylenediaminetetraacetic acid and NaOCl are effective in smear layer removal. Er:YAG laser-activated RCP was comparatively efficient in cleaning the smear layer and opening dentinal tubules. Clinical significance: Er:YAG laser-activated RCP was comparatively efficient in cleaning the smear layer and it can be used for effective removal of smear layer for clinical usage. © 2021 Elsevier B.V., All rights reserved.