Effect of various root canal irrigants as a final rinse on smear layer removal and mineral content of root canal dentin by using scanning electron microscopy and energy-dispersive X-ray spectroscopy: An in vitro study

Aim: This in vitro study compared the effects of 5% Boric acid (BA), 5% carbohydrate-derived fulvic acid (CHD-FA), and 17% ethylenediaminetetraacetic acid (EDTA) as final irrigants on the elimination of smear layers (SLs) and the preservation of mineral content in root canal dentin following an initial irrigation with sodium hypochlorite (NaOCl). Methods: Forty mandibular premolars with a single root were instrumented and decoronated using Protaper Gold F3. Samples were separated into four groups for subsequent irrigation with 5% BA, 5% CHD-FA, 17% EDTA, or saline following irrigation with 5.25% NaOCl. Scanning electron microscopy was used to assess SL removal, and energy-dispersive X-ray spectroscopy examined the mineral composition. Tukey post hoc tests ( P < 0.05) and Kruskal–Wallis tests were used to statistically assess the data. Results: Both 5% CHD-FA and 5% BA achieved smear-layer removal comparable to 17% EDTA, with CHD-FA showing slightly superior cleaning. EDTA caused the greatest mineral loss, whereas CHD-FA and BA showed only about 2%–3% less calcium and 1%–2% less phosphorus loss than EDTA. Saline retained the highest mineral values. Conclusion: Smear-layer removal was comparable to 17% EDTA for both 5% CHD-FA and 5% BA, with CHD-FA exhibiting marginally better cleaning. They provide a more physiologically sound and conservative method of endodontic therapy by effectively removing the SL while reducing mineral loss.