Effect of calcium phosphate (Ca-P) coatings on trabecular bone response: a histological study

The trabecular bone response to noncoated and fluorapatite (FA), hydroxyapatite (HA), and hydroxyapatite heat-treated (HAHT) plasma-sprayed coated implants was investigated in a goat animal model. Forty-eight cylindrical implants were inserted into the trabecular bone of the lateral and medial femoral condyles of twelve goats according to a split plot design. After an implantation period of twelve weeks, the bone-implant interface was evaluated histologically. Quantitative histomorphometrical measurements demonstrated a significant difference in bone contact between implants inserted in the lateral and medial condyles. In addition, a significant difference in bone apposition was observed between the coated and the uncoated implants. Finally, all Ca-P coatings showed reduction in coating thickness. Measurements revealed that FA and HAHT showed less reduction in coating thickness than HA coating. Despite the coating reduction, the bone remained in close contact with the implant surface.