Glass Ceramic Bone Implants

Glass ceramic implants containing 45% SiO2 with a Ca/P ratio of 5 become firmly fixed to bone when placed in a cortical defect of an intact rat femur. The addition of fluoride ions to the implant prevents this fixation. The most significant difference between the two compositions is in their solubilities. The presence of high local concentrations of Ca and PO4 ions at the interface of the soluble non-fluoride containing implant, could account for the deposition of the bone at its surface. It is not felt from these studies, however, that this model will be usable as a mass screening technique for evaluating materials variables. It is felt that other less laborous in vitro systems need to be devised.