Biphasic ceramic bone graft with biphasic degradation rates

In this study, the characteristics of a novel biphasic bone graft are reported. The bone graft is a physical mixture of calcium sulfate (CS) and hydroxyapatite (HA). This biphasic bone graft was prepared by sintering at 1100 °C. Since the degradation rate of CS is much faster than that of HA, the CS/HA biphasic bone graft exhibits two degradation rates. The degradation rate is rapid (~10 wt%/week) in the first stage and then slow (~1 wt%/week) in the second stage. The biphasic bone graft has been implanted into the distal femur of rat. Most the bone graft was degraded 13 weeks postoperatively. Instead, trabecular bone and vascular tissue are observed at the location of implant. The bone graft is unique for its burst of calcium ions at the start and its ability to remain stable throughout the degradation process. Its stable porous structure serves as an ideal scaffold for the formation of new bone as well as vascularization.