From the viewpoint of hard tissue response to implant materials, calcium phosphates are probably the
most compatible materials presently known. During the last few years, much attention has been paid to
hydroxyapatite and β-tricalcium phosphate as potential biomaterials for bone
substitute. A good implantation of biomaterials in the skeleton is to reach full
integration of non-living implant with living bone. The aim of this study is to
compare the resorption kinetics of four kinds of calcium phosphate ceramics:
hydroxyapatite (Ca10(PO4)6(OH)2), hydroxyapatite doped with manganese or
zinc and a composite material of 75% hydroxyapatite and 25% β-tricalcium
phosphate (Ca3(PO4)2). Cylinders (5–6 mm in diameter) of these ceramics were
packed into holes made in the femur diaphysis of mature ovine.
At 2, 4, 8, 12, 16, 20, 28, 36 and 48 weeks after the operation, bone/implant interface
was embedded in polymethylmethacrylate. We used the PIXE method (particle induced
X-ray emission) to measure the distribution of mineral elements (Ca, P, Sr, Zn, Mn and
Fe) at the bone/implant interface. At 4, 8, 16, 28 and 48 weeks after implantation we
studied a biopsy of the ceramics by neutron activation method. Then, we have a global
measurement of mineral elements in the biomaterial. The results showed that the
resorption kinetics of hydroxyapatite doped with zinc was faster than that of the
three other bioceramics.