Borneol-grafted poly(amidoamine) dendrimer with dual antimicrobial and enamel-remineralizing activities against early-stage dental caries

Early caries is initiated by bacterial colonization and biofilm maturation, which drive localized demineralization of enamel. This study developed a borneol-grafted poly(amidoamine) dendrimer to inhibit bacterial adhesion, suppress biofilm formation, and enhance enamel remineralization. Borneol-grafted poly(amidoamine) dendrimer was synthesized via imine linkage and evaluated for antibacterial activity against Streptococcus mutans and Streptococcus sanguinis assessed by adhesion inhibition, and biofilm biomass/viability assays. Mechanisms were explored by zeta potential analysis and scanning electron microscopy. Remineralization was assessed by microhardness, lesion depth, mineral density, X-ray diffraction, and surface morphology; in vivo efficacy was tested on human enamel samples in an intra-oral model. Borneol-grafted poly(amidoamine) dendrimer reduced bacterial adhesion and viability, neutralized surface charge, and affected membrane integrity. In vitro, borneol-grafted poly(amidoamine) dendrimer improved hardness, reduced lesion depth, and increased mineral density; in vivo, it promoted mineralized layers without systemic toxicity. These findings indicate it as a single-scaffold preventive-restorative agent for early-stage caries.