Smear Layer Removal Efficacy of Ultrasonically Activated Herbal Irrigants Compared With 17% EDTA: An Ex-vivo Scanning Electron Microscopic Study

AbstractBackground: This ex-vivo study compared smear layer removal by ultrasonically activated 17% EDTA and 10% aqueous extracts of Neem, Tulsi, Green Tea, and Turmeric using SEM and the Hülsmann scoring system.Materials and Methods: 100 extracted mandibular premolars were assigned to five groups (n = 20). Canals were prepared to size 25/06 (HyFlex EDM) and irrigated with 5.25% NaOCl, followed by the test irrigant with ultrasonic activation and a final NaOCl rinse. SEM evaluation was performed at coronal, middle, and apical thirds.Results: 17% EDTA showed the lowest smear layer scores (median 1.0; IQR 1.0–2.0) at all canal levels. Herbal irrigants demonstrated significantly higher scores, with smear layer persistence increasing apically (p < 0.001). Acceptable smear layer removal occurred in 88.3% of EDTA specimens versus 48.3% (Neem), 11.7% (Tulsi), and 0% (Green Tea, Turmeric). None met non-inferiority criteria.Conclusion: Ultrasonically activated 17% EDTA was superior to all tested herbal irrigants for smear layer removal, particularly in the apical third. Although herbal irrigants exhibit antimicrobial and biocompatible properties, they cannot replace EDTA for smear layer elimination and may be considered only as adjunctive agents. Further studies should focus on optimizing phytochemical formulations to enhance their smear layer removal efficacy.