Current Developments in Antibacterial Nanoparticle-Based Dental Composite Materials: A Comprehensive Overview.

The persistence of secondary caries, biofilm accumulation, and hybrid layer degradation as leading causes of failure in resin-based composite (RBC) restorations underscores the urgent need for materials that can effectively prevent demineralization and promote the remineralization of dental hard tissues. Conventional composites are primarily bioinert, offer minimal defense against cariogenic biofilms, and lack the ability to restore mineral loss at the tooth-restoration interface. Recent advancements in nanotechnology have paved the way for the development of antibacterial and bioactive composites that integrate metallic, metal-oxide, polymeric, organic, and ion-releasing nanoparticles (NPs). These innovative systems provide antimicrobial effects through contact or ion-mediated mechanisms, enhance the stability of the hybrid layer, and increasingly demonstrate potential for remineralization through the controlled release of calcium, phosphate, or fluoride ions. This review provides a critical analysis of the current antibacterial bioactive resin-based nanocomposites employed in dentistry, covering the PubMed, Scopus, Web of Science, and Google Scholar databases with keywords silver (Ag), zinc oxide, titanium dioxide, and magnesium oxide NPs (MgO-NPs); quaternary ammonium polyethylenimine (QA-PEI)-based systems; chitosan-derived NPs; and remineralization-promoting fillers such as bioactive glass (BG) and primarily covering studies published between 2020 and 2026. Key challenges, including NP agglomeration, aesthetic modifications, variable biocompatibility, uncontrolled ion release, and the absence of standardized evaluation protocols, are examined in relation to their impact on predictable remineralization and clinical outcomes. Most current evidence remains preclinical, with limited in situ and early translational validation. This comprehensive narrative review included studies investigating NP-modified dental restorative materials and excluded duplicate records, nondental applications, and studies not relevant to restorative dentistry.