Nanoparticles in Endodontic Sealers: Current Evidence, Mechanisms, and Clinical Perspectives

Abstract

Recent advancements in nanotechnology have introduced a myriad of potential applications in dentistry, with nanomaterials playing an increasing role in endodontics. These nanomaterials exhibit distinctive mechanical and chemical properties, rendering them suitable for various dental applications in endodontics, including obturating materials, sealers, retro-filling agents, and root-repair materials.  Endodontic sealers are central to root canal obturation because they occupy irregularities, interface with dentine, and may contribute to suppressing residual microorganisms. Persistent or recurrent infection—often associated with biofilm survival in anatomically complex spaces—continues to motivate material-level innovations intended to improve antimicrobial activity without compromising handling, sealing, or biocompatibility. Over the past decade, nanoparticle-enabled strategies have emerged as a prominent line of investigation. These strategies include the incorporation of metallic nanoparticles (notably silver-based systems), polymeric nanoparticles such as chitosan, and ion-releasing or bioactive particulate phases, including bioactive glasses, nano-calcium phosphate, and hybrid fillers engineered for adhesive or redox functionality. This narrative review synthesises current evidence on nanoparticles incorporated into, or designed to function alongside, endodontic sealers, focusing on mechanistic rationales, laboratory outcomes, and clinically relevant trade-offs. The literature indicates that nanoparticles can enhance antibiofilm effects through contact-killing or controlled ion release, promote mineral interfacial activity, and tune physicochemical properties such as flow, radiopacity, and microhardness. However, evidence remains predominantly in vitro, with heterogeneity in microbial models, ageing protocols, sealer chemistries, nanoparticle loading and dispersion, and outcome measures. Studies also report that benefits are concentration- and formulation-dependent, and some nanoparticle additions do not improve leakage resistance under relevant conditions. Translational barriers include reproducible nanoparticle dispersion, predictable release kinetics, toxicity and environmental considerations, retreatability, and regulatory classification. Future research that aligns antimicrobial claims with clinically meaningful endpoints, standardised ageing, and robust biocompatibility assessment will be essential before nanoparticle-enhanced sealers can be confidently recommended beyond selected indications.