Fig. 4.

(A) Photograph of sheep implants before implantation, from left to right: porous-coated titanium before alkaline heat treatment, after alkaline heat treatment, and PCHA; and SEM images demonstrating the nanotopographies and microtopographies of the same implants: (B) porous-coated titanium (before alkaline heat treatment), (C) alkaline heat-treated, and (D) PCHA. The SEM analysis demonstrates the change in nanosurface morphology on the porous plasma-sprayed coating before and after alkaline heat treatment processing, where the implant maintained the underlying microporous structure because of plasma-sprayed titanium. In contrast, the PCHA implant surface was characterized by a microcrystalline topography because of the application of hydroxyapatite on the plasma-sprayed titanium coating.