BONE RESPONSE TO SURFACE-MODIFIED TITANIUM IMPLANTS - STUDIES ON ELECTROPOLISHED IMPLANTS WITH DIFFERENT OXIDE THICKNESSES AND MORPHOLOGY

In a series of experimental studies, bone formation was analysed aroun d systematically modified titanium implants. In the present study, mac hined, electropolished and anodically oxidized implants were prepared, surface characterized and inserted in the cortical bone of rabbits (7 wks and 12 wks). SEM, scanning Auger electron spectroscopy and atomic force microscopy revealed no differences in surface composition but m arked differences in oxide thickness, surface topography and roughness . Light microscopic morphology and morphometry showed that all implant s were in contact with bone, and had a large proportion of bone within the threads. The smooth, electropolished implants were surrounded by less bone than the machined implants with similar oxide thickness, (4- 5 nm) and the anodically oxidized implants with thicker oxides (21 nm and 180 nm, respectively) after 7 wks. These studies show that a high degree of bone contact and bone formation can be achieved with titaniu m implants which are modified with respect to oxide thickness and surf ace topography. However, it appears that a reduction of surface roughn ess may influence the rate of bone formation in rabbit cortical bone.