EVALUATION OF PLASMA-SPRAY AND MAGNETRON-SPUTTER CA-P-COATED IMPLANTS- AN IN-VIVO EXPERIMENT USING RABBITS

The bone response to different plasma-spray and magnetron-sputter calc ium phosphate (Ca-P)-coated implants was evaluated in a rabbit animal model. Four types of Ca-P coatings have been investigated: a plasma-sp ray Ca-P coating (HA-PS), a heat-treated plasma-spray Ca-P coating (HA -PS/ht), an amorphous magnetron-sputter coating (Ca-P-a), and a crysta lline magnetron-sputter coating (Ca-P-c). Seventy-two specially design ed cylindrical implants were inserted in the lateral and medial femora l condyles of 18 New Zealand White rabbits. The four differently coate d implants were positioned in one animal according to a split-plot des ign. After implantation periods of 3, 6, and 9 weeks, the bone-implant interface was evaluated histologically. Besides descriptive light mic roscopical evaluation, quantitative histomorphometrical measurements w ere done to determine bone contact and the amount of bone surrounding the implant-bone interface. Light microscopical examination revealed t hat all types of coatings followed the same process of bone healing. M easurements of bone contact at 6 and 9 weeks did not reveal significan t differences between the various coatings. For the amount of bone, in a circular region at a certain distance from the implant, the Ca-P-c- coated implants showed a significantly greater amount of bone after 6 weeks of implantation than did the other three Ca-P coatings. At 9 wee ks this difference could no longer be measured. On the basis of these findings we concluded that magnetron-sputtered Ca-P coatings show the same process of bone healing as the plasma-sprayed Ca-P coatings when inserted into the trabecular femoral bone of rabbits. (C) 1996 John Wi ley & Sons, Inc.