Efficacy of Smear Layer Removal of Human Teeth Root Canals Using Herbal and Chemical Irrigants: An In Vitro Study

Objectives Over many years, many intracanal irrigants have removed smear layers during routine root canal therapy. The efficacies of conventional endodontic chemical irrigants are documented, but limited research is available on herbal irrigants' role in the endodontic therapy irrigation protocol. This study aimed to evaluate endodontic irrigants' smear layer removal efficacy, namely, 3% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), green tea extract, and Triphala extract, using scanning electron microscopy (SEM) analysis. Methods Fifty freshly extracted human permanent maxillary and mandibular single-rooted teeth were collected from the Oral Surgery Department of Regional Dental College (RDC), Guwahati, India. The samples were divided into five groups with 10 teeth each: Group A: sterile distilled water (negative control), Group B: 3% NaOCl, Group C: 17% EDTA, Group D: green tea, and Group E: Triphala (citric acid). Each tooth was then longitudinally split and prepared for SEM inspection under 1000X magnification. The comparison of smear layer removal scores between the groups was done by the Kruskal-Wallis test and Mann-Whitney test, with the significance level set at p<0.01. Results The comparison of the overall mean smear scores and those at different root portions shows that Group C has the lowest mean score, followed by Group E. The pairwise comparison shows that the difference in the mean smear scores between Group C and the other four groups is statistically significant (p-value<0.05). Moreover, the difference in the overall, coronal, middle, and apical mean smear scores between Group A and Group E was highly significant (p-value<0.001). Conclusions The highest smear layer removal efficacy was observed in the samples treated with 17% EDTA. Moreover, the clearing efficacy of Triphala is significantly better than that of distilled water in smear layer removal.