BONELIKE HYDROXYAPATITE INDUCTION BY A GEL-DERIVED TITANIA ON A TITANIUM SUBSTRATE

Gel-derived titania coating on commercial pure (c.p.) titanium induces hydroxyapatite formation onto its surface from a simulated body fluid (SBF, a metastable calcium phosphate solution). The induced apatite is similar to bone apatite in that it is poorly crystallized, calcium-deficient, and carbonate-containing. Furthermore, the carbonate (CO32-) groups go into the apatite lattice and lie at the positions of PO43- and OH- to replace these ionic groups, resembling the (CO32-) groups of bone apatite. Therefore, the apatite induced by the gel-derived titania is said to be bone-like. A chemical stimulation, stemming from abundant hydroxyl groups and negative charges at the surface of the titania gel, is believed to be responsible for the bonelike apatite induction. The potential of bone-bonding is predicted for the gel-derived titania, for it is an efficient bone-like apatite inducer in the SBF.