Background: Persistent microbial infection is a primary cause of endodontic failure, and novel antimicrobial strategies are being explored to enhance root canal disinfection. Among these, silver nanoparticles (AgNPs) have shown promise due to their unique physicochemical properties and broad-spectrum antimicrobial activity.

Objective: To assess the current evidence on the effectiveness of nano silver (AgNPs) when used as an irrigant or intracanal medicament in endodontic therapy.

Methods: A systematic search of PubMed, Ovid, and Cochrane Library databases was conducted using the Mesh terms "Nano silver," "AGNPs," "Dental," "Dentistry," "Endodontics," and "Root canal therapy." Studies included in vitro, in vivo, and ex vivo models assessing AgNPs alone or in combination with other agents. Selection was guided by predefined PICOS criteria. Of 242 records identified, 26 full-text articles were assessed, with 24 studies included in the synthesis. A PRISMA flow diagram illustrates the selection process.

Results: AgNPs demonstrated greater antimicrobial efficacy when used as an intracanal medicament compared to an irrigant. Most studies focused on in vitro evaluations against E. faecalis biofilms. Several formulations, including gels, core-shell particles, and combinations with lasers or CHX, enhanced efficacy. Cytotoxicity assays indicated that AgNPs are generally less toxic than conventional irrigants like sodium hypochlorite and chlorhexidine.