Bone formation following implantation of fibrous calcium compounds (beta-Ca(PO3)2, CaCO3(aragonite)) into bone marrow.

Bone formation around three types of fibrous calcium-containing crystals has been examined histologically using rats. The implanted materials are (i) calcium metaphosphate (beta-Ca(PO(3))(2)) fibers having aspect ratios of 15-80 with 2-20 microm in diameter, (ii) beta-Ca(PO(3))(2)) fibers surface-modified using dilute NaOH and (iii) calcium carbonate (CaCO(3); aragonite phase) whiskers having aspect ratios of 15-40 with 0.5-3 microm in diameter.