Apatite--wollastonite containing glass ceramic granule-fibrin mixture as a bone graft filler: use with low granular density.

The purpose of this study was to investigate bone formation after implantation of a mixture of apatite--wollastonite containing glass ceramic granules (A-W.GC, 220-355 microns) and fibrin glue with a low A-W.GC granular density. The fibrinogen was prepared from rat blood plasma. A mixture of A-W.GC granules and fibrin glue 1:4 in volume ratio (1:4 mixture) was implanted in the proximal metaphysis of the rat tibia, and bone formation was evaluated quantitatively by histomorphometry in undecalcified specimens. Microangiography was performed in animals sacrificed 5 days after the operation. The results were compared with those of a previous study in which a 1:1 mixture of A-W.GC granules and fibrin glue was used. With the 1:4 mixture, the A-W.GC density was 39.7% because of concentration of fibrin at packing. Good early vascularization comparable to that after implantation of the 1:1 mixture was observed. Bone formation proceeded at the same rate as after implantation of 1:1 mixture, but the level of the plateau was higher than that for the 1:1 mixture. The osteoconductive potential of the 1:4 A-W.GC-fibrin mixture was similar to that of the 1:1 mixture, and was higher than that of A-W.GC without fibrin.