Effect of surface roughness and calcium phosphate coating on the implant/bone response

The influence of surface roughness and calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated. Four types of tita nium implants, i.e. as-machined, grit blasted, as-machined with Ca-P sputte r coating, and grit blasted with Ca-P sputter coating, were prepared. The C a-P sputter-coating, produced by using the RF magnetron sputter technique, was rapid heat-treated with infrared radiation at 600 degrees C. These impl ants were inserted into the left and right femoral condyles and the left an d right tibial diaphyses of the rabbits. After implantation periods of 2 an d 12 weeks, the bone-implant interface was evaluated histologically and his tomorphometrically. Histological evaluation revealed no new bone formation around different implant materials after 2 weeks of implantation. After 12 weeks, bone healing was almost completed. For both tibial and femoral impla nts, Ca-P coated implants always showed a higher amount of bone contact tha n either of the non-coated implants. On the other hand, surface roughness i mproved only the response to implants inserted into the tibial diaphysis. O n the basis of these findings, we concluded that 1) deposition of a sputter ed Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase, and 2) besides implant surface co nditions the bone response is also determined by local implant site conditi ons.