Effect of silicon doping on bone formation within alumina porous domains

The effect of doping a porous bioinert bioceramic with silicon (Si) on tissue ingrowth, differentiation, and osteogenesis was studied using a rat intramedullary model. Alumina tubes (1.3‐mm outer diameter, 0.6‐mm inner diameter, 15‐mm length) doped with Si at nominal concentrations of 0.5 and 5.0 mol % were implanted into femoral medullary canals of female rats for 16 weeks. Tissue formation within the tubes was determined by histology and histomorphometry. Addition of 0.5 mol % Si to alumina stimulated cellular activity at the bone–ceramic interface and impaired osteogenic maturation within the tubes. In contrast, osteogenesis was enhanced in the 5.0 mol % Si‐doped alumina tubes. It is considered that effect of Si is related to surface chemistry rather than microstructure. This work demonstrates that doping a bioinert ceramic with small amounts of Si can significantly alter tissue ingrowth, differentiation, and osteogenesis within a porous implant. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 250–257, 2004