Apatite-coated implant surfaces exhibit superior biological, immunological, and mechanical properties compared to sandblasted acid-etched surfaces.

Implant surface modification techniques have shifted from simple mechanical modifications to sophisticated strategies aimed at modulating biological responses at the bone-implant interface. This study aimed to compare sandblasted, large-grit, acid-etched (SLA) and apatite-coated dental implant surfaces, focusing on their biological, immunological, and mechanical performance. Surface morphology and wettability were assessed by field emission scanning electron microscopy and liquid spreading tests, respectively. In vitro assays evaluated osteoblast adhesion, alkaline phosphatase (ALP) staining, and mineralization. In vivo performance was examined using rat femoral condyle loosening and calvarial defect models to assess early bone formation, macrophage polarization, and vascular endothelial growth factor (VEGF) expression. A beagle mandibular tooth extraction model was used to measure removal torque (RT) and bone-to-implant contact (BIC). The apatite-coated surface exhibited a uniform nanostructured apatite layer with superior wettability compared to the SLA surface. In vitro, apatite-coated surface significantly enhanced osteoblast adhesion and mineralization (p < 0.05). In vivo, apatite-coated surface promoted peri-implant bone formation, accelerated the shift from M1 to M2 macrophages, and increased VEGF expression. In the beagle model, apatite-coated implants demonstrated higher RT and BIC at all time points. Apatite-coated on dental implants enhances osseointegration through combined biological, mechanical, and immunomodulatory effects, promoting rapid bone healing and stable implant fixation.