MECHANICAL AND HISTOLOGIC EVALUATION OF CA-P PLASMA-SPRAY AND MAGNETRON SPUTTER-COATED IMPLANTS IN TRABECULAR BONE OF THE GOAT

The aim of this study was to investigate the bone response to calcium phosphate (Ca-P) plasma-spray and radiofrequency magnetron sputter-coa ted implants with comparable roughness. Therefore, tapered conical scr ew designed implants were installed in the trabecular bone of the femu rs of nine goats. They were provided with two types of coatings, a pla sma-spray dual coating of fluorapatite and hydroxyapatite (FA/HA-PS) a nd a titanium plasma-spray coating, covered with an amorphous Ca-P mag netron sputtercoating (TPS/Ca-P-a). These implants were evaluated hist ologically and mechanically after 3 months of implantation. A well-con trolled method to apply and measure a torsional force to load the scre w-type implants to the point of failure was introduced. All implants h ealed uneventful and were well fixed. No significant difference (Stude nt t test, p > 0.05) for the torsional failure force was measured for both type of coatings. Nevertheless, SEM revealed differently situated fracture planes. Light microscopy showed intimate bone-implant contac t for both types of coatings; original drill margins were still visibl e. A lamellar type of bone with some remodeling lacunae was shown. His tomorphometry revealed a higher percentage of bone contact for the FA/ HA-PS-coated implants (student t test, p < 0.05). Measurement of the a mount of bone revealed more bone mass around TPS/Ca-P-a-coated implant s (analysis of variance and Tukey multiple comparison, p < 0.05). (C) 1997 John Wiley & Sons, Inc.