Quantitative comparison of bone growth behavior in granules of Bioglass (R), A-W glass-ceramic, and hydroxyapatite

The hypothesis that bioactive glass particulate increases the rate of bone proliferation over that of synthetic hydroxyapatite and bioactive glass-cer amic was tested in these experiments. Three types of bioactive particles-45 S5 Bioglass(R) synthetic hydroxyapatite, and A-W glass-ceramic-were implant ed in 6-mm-diameter holes drilled in the femoral condyles of mature rabbits . Bone growth rate was measured using an image processor. 45S5 Bioglass(R) produced bone more rapidly than either A-W glass-ceramic or hydroxyapatite. At the later time periods, 45S5 Bioglass(R) was resorbed more quickly than A-W glass-ceramic. Synthetic hydroxyapatite was not resorbed at all. Backs cattered electron imaging suggested that the resorption process occurred by solution-mediated dissolution, which produced chemical changes in the encl osed particulate. It was concluded that the rate of bone growth correlates with the rate of dissolution of silica as the particles resorb. (C) 2000 Jo hn Wiley & Sons, Inc. J Biomed Mater Res, 51, 37-46, 2000.