The importance of surface roughness for implant incorporation

318 threaded implants with a diameter of 3.7 mm, length 6 to 7 mm and a pitch-height of 0.6 mm were inserted in 56 New Zealand white rabbits. Implants of varying surface roughness were produced by a blasting procedure using 25, 75, and 250 mu m sized particles. As-machined, (i.e. turned) implants served as controls. The implant surface roughness was measured with the confocal laser scanner (TopScan 3D), and appropriate software was used for visual and numerical characterization. After implantation time of 4 weeks, 12 weeks or 1 year, the animals were euthanized. The implants were evaluated with respect to the peak removal torque, the percentage of bone-to-implant contact. The results from the animal experiments demonstrated, generally, higher removal torques and higher percentages of bone-to-implant contact for implants blasted with 25 and 75 mu m sized blasting particles than with as-turned or 250 mu m blasted implants. The corresponding average height deviation for the 4 surfaces was 1 mu m, 1.5 mu m, 0.7 mu m, and 2.0 mu m. When comparing the 25 and the 75 mu m blasted implants it was found that 75 mu m blasted screws showed the strongest bone fixation. (C) 1998 Elsevier Science Ltd.