Scanning Electron Microscopic Comparison of Emblica officinalis Extract, EDTA, and Maleic Acid for Smear Layer Removal From Root Canal Dentin

Background: Formation of a smear layer during canal preparation impedes the penetration of irrigants, medicaments, and sealers, posing a challenge to optimal endodontic results. This study compared the efficacy of 6.25% Emblica officinalis extract, 17% ethylenediaminetetraacetic acid (EDTA), 7% maleic acid, and normal saline in removing the smear layer from root canal dentin. Methods: A total of 48 single-rooted human teeth extracted with fully developed apices were decoronated, standardized to 17 mm, and instrumented using a hybrid technique. Samples were randomly assigned to four groups of 12 (n = 12) as follows: group I - 17% EDTA, group II - 6.25% Emblica officinalis extract, group III - 7% maleic acid, and group IV - normal saline (control). Each canal was irrigated with 5 mL of the assigned solution for 1 min using a side-vented needle. Longitudinally sectioned specimens were observed under scanning electron microscopy (SEM), and the extent of smear layer elimination across the coronal, middle, and apical thirds was determined using Hülsmann’s criteria. Data were analyzed using one-way analysis of variance, Tukey's post hoc test, and Kruskal-Wallis analysis as a confirmatory test (p < 0.05). Results: Seven percent maleic acid demonstrated significantly greater smear layer removal in the apical and middle thirds than the other irrigants (p < 0.05). Seventeen percent EDTA showed comparable efficacy in the coronal third. The 6.25% aqueous extract of Emblica officinalis exhibited moderate smear layer removal. Normal saline was the least effective irrigant across all canal regions. Conclusions: Maleic acid at 7% emerged as the most effective irrigant for smear layer removal, surpassing 17% EDTA, 6.25% aqueous extract of Emblica officinalis, and normal saline. These results clearly indicate that conventional chelating agents, especially maleic acid, are superior to the evaluated herbal irrigant in achieving effective smear layer removal from root canal dentin.