Selenium nanoparticles (SeNPs) appear to show strong antimicrobial and antioxidant effects, possibly making them a favorable, multifunctional option for root canal disinfection, reports a study recently published in BMC Oral Health.
Additionally, SeNPs may show lower toxicity, supporting their potential as a safer alternative to traditional root canal irrigants, the authors wrote.
“SeNPs demonstrate promising antimicrobial efficacy, biocompatibility, and favorable dentinal interactions,” wrote the authors, led by Salma Genena of Alexandria University in Egypt (BMC Oral Health, January 9, 2026).
The study evaluated the antibacterial efficacy, cytocompatibility, and dentinal interactions of SeNPs as a potential endodontic irrigant compared with sodium hypochlorite (NaOCl), the current gold standard. SeNPs were synthesized using an ascorbic acid-mediated method and characterized for their physicochemical properties. Twenty-four extracted human single-rooted teeth with mature apices and straight canals were included, they wrote.
Antibacterial activity against Enterococcus faecalis (E. faecalis) was measured using the minimum inhibitory concentration method, while cytotoxicity was assessed on oral epithelial cells and human gingival fibroblasts using an MTT assay. Teeth inoculated with E. faecalis biofilms for 21 days were irrigated with either NaOCl or SeNPs, and dentinal surfaces were analyzed using scanning electron microscopy (SEM).
SeNPs displayed a spherical morphology with an average particle size of 93.15 nm and good colloidal stability. Antibacterial testing showed effective activity at a minimum inhibitory concentration of approximately 128 µg/mL. Cytocompatibility results demonstrated an acceptable safety margin, with half maximal inhibitory concentration (IC50) values of 626 µg/mL for oral epithelial cells and 809 µg/mL for human gingival fibroblasts, they wrote.
Furthermore, SEM analysis revealed bacterial reduction with both irrigants, with NaOCl at 2.5%, achieving complete smear layer removal and open dentinal tubules, while SeNPs measured 128 µg/mL, causing partial tubule occlusion with scattered nanoparticle deposits. Overall, both irrigants reduced E. faecalis biofilms, with NaOCl showing superior antimicrobial performance, while SeNPs demonstrated significant antibacterial activity and potential for dentin sealing.
The study, however, had limitations. The use of straight canals improved reproducibility but did not account for the complex anatomy of curved or multirooted molars.
Future studies should test SeNPs in molar models to better reflect clinical conditions, the authors added.
“SeNPs represent a promising candidate for further investigation, particularly targeting E. faecalis, the persistent pathogen in endodontic infections,” Genena and colleagues wrote.
