The next frontier in antibacterial dental resins: A 20-year journey of innovation and expectations

OBJECTIVE: Dental resin composites remain fundamental in restorative dentistry, but premature failures often compromise their long-term success Secondary caries, driven by acidogenic bacteria, salivary enzymes, and mechanical stresses. These failures frequently require complete restoration replacement, leading to increased costs and further loss of healthy tooth structure. DATA: This critical review examines two decades of relevant literature on innovation in antibacterial resin technologies, from early soluble additives (e.g., silver, fluoride, chlorhexidine) whose rapid leaching undermined mechanical performance to covalently bound quaternary ammonium monomers (QAMs) that provide durable, contact-active antimicrobial effects without significant filler loss. We further evaluate the integration of nanotechnology-metal-oxide nanoparticles, halloysite nanotubes, and graphene derivatives-to achieve sustained antimicrobial efficacy at low filler loadings, as well as emerging approaches using antimicrobial peptides, ionic liquids and piezoelectric fillers for environment-responsive action. SOURCES: Peer-reviewed research articles and reviews were identified primarily via PubMed, Scopus, and Web of Science. CONCLUSION: Early soluble additives effectively reduced bacteria, but they leached out too quickly, weakening the material. Quaternary ammonium compounds (QAMs) addressed this issue by offering long-lasting, surface-active antimicrobial properties. Nanofillers also provide sustained antimicrobial effects at low concentrations but face challenges such as particle clustering, potential toxicity, and uneven dispersion. New antimicrobial strategies like peptides, ionic liquids, and piezoelectric fillers show potential but face challenges such as biocompatibility, biofilm complexity, and limited real-world testing. Advancing these materials will require better preclinical models, cross-disciplinary collaboration, and computational tools to optimize antibacterial function and material strength.