Bioactive ZnP-coated 3Y-TZP ceramics for dental implants: Strong interfacial bonding, antibacterial activity, and...

To fabricate a zinc phosphate (ZnP) coating on 3 mol% yttria-stabilized tetragonal ZrO₂ polycrystal (3Y-TZP) with enhanced mechanical strength, adhesion, cytocompatibility, antibacterial activity, and osteogenic performance, this study offers a new approach for improving dental implants.

The ZnP coating was synthesized on a substrate via hydrothermal treatment (150-250 ℃, 3 h) using a solution of zinc oxide, phosphoric acid, and nitric acid. The coated samples were characterized in terms of physicochemical properties, adhesion strength, flexural strength, and fracture morphology. Cellular responses, including viability, proliferation, and osteogenic differentiation, were assessed using CCK-8 assay, live/dead staining, phalloidin staining, alkaline phosphatase/Alizarin Red S assays, and real-time PCR. Antibacterial properties were evaluated based on colony-forming unit counts and bacterial adhesion assays in a rat subcutaneous infection model. Finally, in vivo bone formation and biosafety were analyzed by micro-computed tomography and histological examination after implantation.

Increasing the hydrothermal temperature improved the coating thickness, roughness, wettability, and mechanical stability. The ZP-250 sample exhibited a 5B adhesion strength, which significantly enhanced MC3T3-E1 cell proliferation, osteogenic differentiation, mineralization, and gene expression. Moreover, it demonstrated strong antibacterial effects against S. aureus and E. coli, promoted osseointegration, and showed full biosafety in a jaw defect model.

The ZnP coating markedly improved the bioactivity of 3Y-TZP, addressing the challenge of bioinertness in dental implants. This innovation enhances long-term stability and clinical success, showing promising potential for clinical application.