Effects of the carbonate content in carbonate apatite on bone replacement

Carbonate apatite (CO₃ Ap), an inorganic component of human bone, has been clinically applied as an artificial bone substitute. In this study, the effects of the CO₃ content in CO₃ Ap on the replacement by new bone were studied by fabricating CO₃ Ap granules containing 0.9-8.3 wt% of CO₃ . The dissolution rate of CO₃ Ap in a weak acidic solution, mimicking the Howship's lacunae, was rapid for the CO₃ Ap granules containing a larger amount of CO₃ . Histological analyses demonstrated the rapid resorption in CO₃ Ap and replacement by natural bone tissue when the CO₃ content was increased. Therefore, the CO₃ content in CO₃ Ap is a key factor that influences the replacement of the bone tissue.