The influence of compositional variations on bone ingrowth of implanted porous calcium aluminate ceramics.

Sixteen ceramic specimens were implanted in the femur of mature rhesus monkeys. The specimens consisted of four groups of a basic calcium aluminate composition with additions of 5, 10, 15 and 20 wt% phosphorous pentoxide (P2O5). The increasing amounts of P2O5 caused variations in the resorption rate, microstructure and surface characteristics of the implant. The influence of these variables on bone and tissue growth within and about the implant was investigated. After sacrifice the ceramic-bone specimens were studied by a tetracycline-based histological analysis, scanning electron microscopy and energy dispersive analysis. The results indicate an increase in mesenchymal cell proliferation, fibrous and bone tissue formation at the ceramic tissue interface and within the implant with increasing concentrations of P2O5. The results obtained from the study did not furnish sufficient evidence to differentiate between the direct chemical influence the increasing P2O5 had on osseous tissue formation or the indirect influence that may have resulted from its effect on the ceramic microstructure and morphology.