Histological and biochemical evaluation of osteogenic response in porous hydroxyapatite coated alumina ceramics.

We compared the osteogenic response in porous alumni (Al) and hydroxyapatite coated porous alumni ceramic (HA/Al) by grafting rat bone marrow cells with these implants subcutaneously in the back of syngeneic rats. The ceramics did not show any bone formation without marrow, but did when combined with marrow cells. The osteogenesis in HA/Al began directly on the ceramic surface, but in Al began away from the ceramic surface, and fibrous tissue interposition was seen between the de novo bone and its surface. Alkaline phosphatase activity and bone specific bone gla protein content in HA/Al with marrow were both about three times higher than in Al with marrow. These results indicate that HA/Al has excellent osteoconductive properties and that a composite of marrow and HA/Al is clinically applicable osteogenic biomaterial.