Abstract:The effects of surface-modified porous titanium implants with different porosities and pore sizes on osseointegration were investigated in vivo. Three porous titanium implants (A30, A40 and A50 containing volume fractions of space-holder NaCl being 30%, 40% and 50%, respectively) were manufactured by metal injection moulding (MIM). The surface-modified implants were implanted into muscles and femurs of hybrid male dogs. Interface osteogenic activity and histological bone ingrowth of porous titanium implants were evaluated at 28, 56 and 84 d. The results showed that when additive space-holder amount of NaCl increased from 30% to 50% (volume fraction), the general porosity and mass fraction of macropores of porous titanium rose from 42.4% to 62.0% and from 8.3% to 69.3%, respectively. Histologic sections and fluorescent labeling showed that the A50 implant demonstrated a significantly higher osteogenic capacity at 28 d than other implants. Bone ingrowth into the A30 implant was lower than that into other implants at 84 d. Therefore, the pore structure of A50 implant was suitable for new bone tissue to grow into porous implant.

Key words: porous titanium implant; porosity; aperture; interconnectivity; osseointegration