Structural, dielectric, and biological evaluation of silver-doped hydroxyapatite nanocomposites for dental applications

• Silver-doped hydroxyapatite nanoceramics were successfully synthesized with preserved hexagonal apatite structure across all Ag concentrations. • Ag incorporation induced controlled lattice distortion and defect generation, evidenced by reduced crystallite size, increased microstrain, and modified dielectric response. • Dielectric constant, dielectric loss, and AC conductivity exhibited strong frequency dependence, governed by interfacial polarization and defect-assisted charge transport mechanisms. • Ag doping significantly enhanced AC conductivity following Jonscher’s universal power law, confirming dominant hopping-based conduction at high frequencies. • A clear structure–property–biological performance correlation was established, identifying an optimal Ag concentration that balances dielectric behavior, antimicrobial efficiency, and cytocompatibility. Silver (Ag) incorporation into hydroxyapatite(HA) was investigated to modulate dielectric behavior and biological functionality for dental nanocomposites applications. A series of Ag-incorporated HAnanocomposites were synthesized via a microwave-assisted precipitation method. This approach enabled rapid crystallization and compositional homogeneity. Structural analysis revealed that the hydroxyapatite lattice remained stable at low Ag content. At higher concentration, secondary crystalline phase emerged. Scan electron microscopy showed that increasing Ag content alters particle connectivity and agglomeration behavior. Compositional mapping also suggested slight deviations in the Ca/P stoichiometry. Dielectric properties over a wide frequency range showed that Ag addition influences polarization dynamics, re This results in variations in permittivity(ε′), dielectric loss(ε′′), and AC conductivity( σ ac ) . Biological evaluation indicated a composition dependent response. Low Ag content preserved high cytocompatibility toward WI-38 normal fibroblast cells, while higher content increased cytotoxicity. . In contrast, antimicrobial activity against bacterial strains improved with increasing Ag content. Correlating dielectric response with biological performance suggests an optimal Ag concentration that balances antimicrobial efficacy with cellular safety. These findings provide insight into the design of Ag-doped hydroxyapatite nanocomposites for advanced dental applications.