AMOUNT OF HYDROXYL RADICAL ON CALCIUM-ION-IMPLANTED TITANIUM AND POINT OF ZERO CHARGE OF CONSTITUENT OXIDE OF THE SURFACE-MODIFIED LAYER

To compare the surface properties of calcium-ion (Ca2+)-implanted tita nium with those of titanium and to investigate the mechanism of bone c onductivity of Ca2+-implanted titanium, amounts of hydroxyl radical of Ca2+-implanted titanium and titanium were estimated. Also, the point of zero charge (p.z.c.) of oxide constituting surface oxides of Ca2+-i mplanted titanium and titanium was determined. Results showed that the amount of active hydroxyl radical on Ca2+-implanted titanium was foun d to be significantly larger than that on titanium, indicating that th e number of electric-charging sites of Ca2+-implanted titanium in elec trolyte is more than that of titanium. The p.z.c. values of rutile (Ti O2), anatase (TiO2), and perovskite (CaTiO3), were estimated to be 4.6 , 5.9, and 8.1, respectively. Thus, Ca2+-implanted titanium surface is charged more positively in bioliquid than titanium,accelerating the a dsorption of phosphate ions. (C) 1998 Chapman & Hall.