THE INTRA OSSEOUS REACTION OF POROUS HYDROXYAPATITE AND β-TRICALCIUM PHOSPHATE WITH THE SAME STRUCTURE

The bone ingrowth in hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) was not clearly explained in the past investigation. We understand this confusion was due to the difference of the porosity and pore size of the implant materials, and impurities and the heterogeneous chemical composition of the materials. In this study, pure HA and pure β-TCP with the same structure were implanted in the distal femurs of 24 mature male rabbits. The amount of ceramics and of regenerated bone were measured after 4, 12 and 24 weeks, respectively. There was a large amount of bone in β-TCP at 4 weeks, but they decreased at 24 weeks. Meanwhile there was the smaller amount of regenerated bone in HA at 4 weeks, but increased at 12 and 24 weeks, and then decreased after 24 weeks. The peak value of the amount of regenerated bone in HA and β-TCP was almost the same.