The trabecular bone response to noncoated and fluorapatite (FA), hydroxyapatite (HA), and hydroxyapatite heattreated (HAHT) plasma-sprayed coated implants was in vestigated in a goat animal model. Forty-eight cylindrical implants were inserted into the trabecular bone of the lat eral and medial femoral condyles of twelve goats according to a split plot design. After an implantation period of twelve weeks, the bone-im plant interface was evaluated histologically. Quantitative histomorphometrical measure ments demonstrated a significant difference in bone contact

Various studies already have shown that the occurrence of oral implant failure is higher in the maxilla than in the man dible. To learn whether Ca-P coatings can improve the suc cess rate of oral implants in the maxilla, three different plasma-sprayed, Ca-P-coated, self-tapping Branemark® im plants were inserted in the trabecular bone of the maxilla. Before the insertion of the implants, the two first upper pre molars of 16 goats were bilaterally extracted. Four months later, each animal received four types of implants: three dif ferent Ca-P-coated types and one uncoated. After an endosseous period of 6 months, the implants were provided with permucosal abutments. Four months later the animals were killed. At the end of the experiment, it appeared that 10 of the 16 installed noncoated implants had failed while of the 48 Ca-P-coated implants, only 6 had failed. All successful implants were retrieved and prepared for histomorpho metrical evaluation of the bone and gingiva response. The Ca-P-coated implants showed a significantly greater per centage of bone in contact with the implant surface com pared with the uncoated implants. The length of the epithe lium was not significantly different for the coated compared to the uncoated implants, b ut the connective tissue was sig nificantly thicker for the noncoated implants than for the Ca-P-coated implants. Also, measurements revealed that all coatings showed reduction in thickness. On the basis of these findings, we concluded that the application of Ca-P coatings (1) improves the bone-implant reaction, although all coatings reduced in thickness, and (2) is of benefit during the healing period in less mineralized trabecular bone.

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