Influence of Ca and P on the structure and properties of bio-machinable glass-ceramics

The effects of Ca and P on the crystallization characteristics, microstructural morphology and machinability of mica/apatite glass-ceramics were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), scanning electron microscopy (S EM) and a drilling test. The results indicate that additions of CaO and P2O5 broaden the mica crystallization peaks, shift them to lower temperatures and weaken the peak intensities. The main crystals found in the glass-ceramics are fluorapatite and fluorophlogopite. Generally the machinability of glass-ceramics declines markedly as Ca and P increase. Glass-ceramic sample G20 (with 20 parts by weight CaO to 100 parts of the base glass), however, still possesses relatively high machinability. In vivo tests indicate that clear bone formation occurs after implantation for 14 days, and show that this material is promising for healing of bone defects.