“Silver Nanoparticles as Endodontic Irrigants: A Scoping Review of Antibacterial Efficacy from In Vitro and Ex Vivo Studies”

Background: The disinfection of the root canal system is paramount to successful endodontic therapy. Enterococcus faecalis, a persistent endodontic pathogen, has demonstrated resistance to conventional irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Silver nanoparticles (AgNPs), with their multifaceted antimicrobial mechanisms, have emerged as potential adjuncts in root canal disinfection. Objective: This scoping review aims to systematically map the available literature evaluating the antibacterial efficacy of AgNPs as endodontic irrigants in in vitro and ex vivo settings. Methods: Following the PRISMA-ScR guidelines, a systematic search was conducted across PubMed, Scopus, and Web of Science databases. Studies assessing the use of AgNPs against endodontic pathogens were included. Data were extracted on particle size, concentration, activation methods, test models, and comparative outcomes. Results: Twenty eligible studies were analyzed. AgNPs demonstrated consistent antimicrobial activity against E. faecalis, with enhanced efficacy observed when particle sizes were <20 nm and concentrations ≥100 ppm. Adjunctive activation methods such as passive ultrasonic irrigation (PUI) and photodynamic therapy (PDT) significantly improved performance. Several studies reported AgNPs outperforming NaOCl and CHX in bacterial reduction and biofilm disruption. However, variations in synthesis methods, formulations, and outcome measures limited direct comparability. Conclusion: AgNPs show promise as adjunctive or alternative endodontic irrigants. Their antimicrobial efficacy, especially when combined with activation techniques, warrants further investigation through standardized clinical trials. Consistent formulation protocols and robust biocompatibility data are essential for clinical translation.Author Contributions (CRediT taxonomy): Dr. Sidharth Menon – Conceptualization, Methodology, Data Curation, Formal Analysis, Writing – Original Draft, Visualization, Supervision Dr. Kailash Attur – Review & Editing, Validation, Resources, Methodological Oversight, Project Administration (Endodontic domain guidance) Dr. Shylaja Attur – Resources, Validation, Literature Mapping (Oral Microbiology), Review & Editing, Methodology Alignment Prof. Mohammed Mustafa – Transdisciplinary Integration, Strategic Supervision, Conceptual Refinement, Writing – Review & Editing, Final Approval Affiliated Institutions: Narsinhbhai Patel Dental College and Hospital, Sankalchand Patel University Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University “No funding” and “No conflict of interest” declarations are retained and clearly visible.