Purpose: To test the antimicrobial properties, surface topography, reaction of surrounding tissue (biocompatibility), and osseointegration of ultrathin implant surfaces containing polysiloxane and nanoscaled silver particles. Materials and Methods: Implants with polysiloxane coating and nanoscaled silver particles (Ag/SiOxCy; HyProtect, Bio-Gate) were compared with implants with polysiloxane coating alone and with noncoated (grit-blasted and acid-etched) implants. A total of 72 implants were inserted into the calvaria of eight domestic pigs (nine implants each, three of each type). After 3 months, histologic sections were evaluated for inflammatory cell infiltration and bone implant contact. Results: Roughness parameters did not differ between all three implant types. The Ag/SiOxCy coating exhibited a good antimicrobial effect in vitro and no sign of inflammatory cell infiltration in vivo. The noncoated implants demonstrated 10.85% and 14.48% more bone contact than the polysiloxane-coated implants (P = .003) and the Ag/SiOxCy‑coated implants (P ≤ .001), respectively. Osseointegration was not significantly different between the Ag/SiOxCy‑coated and polysiloxane-coated implants (P = .72). Conclusion: The osseointegration capability of the Ag/SiOxCy-coated implants was equal to that of the polysiloxane-coated implants but less than that of the grit-blasted and acid-etched implants. Because of the biocompatibility of the polysiloxane coating, further studies should be conducted in load-bearing models and in the oral cavity to investigate the antimicrobial effect of the embedded silver clusters. Schlagwörter: implant coating, implant surface, in vivo model, polysiloxane coating, silver coating