Comparative Evaluation of Smear Layer Removal by Different Root Canal Irrigants: An In Vitro Scanning Electron Microscopic Study

Irrigation is crucial for effective debridement and removal of the smear layer while performing root canal therapy.The smear layer, which is composed of organic and inorganic debris from instrumentation, can hinder endodontic success if not adequately removed.This study compares the efficiency of sodium hypochlorite (NaOCl), RISA, and SmearOFF in eliminating the smear layer at different levels of the canal with the help of SEM, i.e., scanning electron microscopy.Materials and methods: Thirty extracted human mandibular first premolars with single roots and mature apices were used.Teeth with decay or anatomical variations were excluded.After completion of the teeth preparation, they were randomly divided into three groups, each group comprising 10 samples for final irrigation: Group I used NaOCl with ultrasonic activation, group II used RISA, and group III used SmearOFF.Results: Results showed that RISA was significantly more effective in smear layer removal at all levels (mean scores: coronal -0.70, middle -0.40, apical -0.30) compared to NaOCl and SmearOFF, which had higher scores.Conclusion: In conclusion, RISA is more effective than both NaOCl and SmearOFF for smear layer removal during root canal therapy, suggesting it as a better alternative for endodontic irrigation and potentially improved outcomes.Clinical significance: This study highlights RISA as a superior irrigant compared to NaOCl and SmearOFF, particularly at the apical third, which is often the most challenging area to clean.