[Preparation of decalcified bone matrix, bone cement and bone morphogenetic protein composite]

To investigate the most excellent composite proportion and the most convenient composite method of decalcified bone matrix (DBM), bone cement (BC) and bovine bone morphogenetic protein (bBMP) composite.

The canine DBM and the bBMP were prepared beforehand. First mix the bBMP and DBM together with the proportion of 1:25 with adsorption and directly, then add BC with different weight proportion and finally the complex material was examined by biomechanics, scan electron microscope, determination of bone inductive activity and implanted into the canine femoral defect caused by microwave-induced hyperthermia.

The bBMP had strong bone inductive activity and had no affect for this function when combined with DBM with different method. There were irregular gaps in the composite and most of them with diameter less than 100 microns and the porosity of the composite was less than 20% when the proportion of DBM was 40%. So it was unfavorable for the new bone to form and the new blood vessels to reconstruct. The DBM and BC could not be combined together when the proportion of DBM was 80%. While the biomechanical intensity of the composite decreased and the qualities of the new bone forming and new blood vessels reconstructing improved successively when the proportion of DBM was from 50% to 75%.

It is the most convenient that bBMP is combined with DBM directly while its bone inductive activity could not be affected. The composite material not only has high biomechanical intensity, but also is favorable for new bone to form and new blood vessels to reconstruct when the proportion of DBM is 50% and 60%. So it is favorable for bone repair in the places where need to bear a load. However it is also favorable for bone repair in the places where do not need to bear a load when the proportion of DBM is 75%.