AN ANIMAL STUDY OF CP TITANIUM SCREWS WITH DIFFERENT SURFACE TOPOGRAPHIES

Sixty screw-shaped commercially pure (c.p.) titanium implants were inserted in the tibial and the femoral metaphyses of adult rabbits. The implants were divided into four groups with different surface roughnesses. The surface roughness was characterized before and after implant insertion. One group was left as-machined, this group had an initial R(a) value of 0.4 mu m. Two groups were blasted with 25 Cim sized particles of TiO2 and Al2O3, respectively; corresponding Ra( )values for these groups were 0.9 mu m and 0.8 mu m One group was blasted with 250 mu m sized particles of Al2O3 The R(a) value for this last group was 2.1 mu m. After a healing time of 12 weeks the torque necessary for implant removal and histomorphometric evaluations was evaluated. After removal of the implants the R(a) values for the four above mentioned groups were 0.9, 1.3, 1.1 and 1.9 mu m, respectively. We found a better bone response for implants blasted with 25 mu m sized particles compared to an as-machined (turned) surface, but no differences between the implants blasted with 25 mu m particles and the implants blasted with 250 mu m sized particles.