Hm. Kim et al., APATITE-FORMING ABILITY OF ALKALI-TREATED TI METAL IN BODY ENVIRONMENT, Nippon Seramikkusu Kyokai gakujutsu ronbunshi, 105(2), 1997, pp. 111-116
The essential requirement for an artificial material to bond to living
bone is the formation of bonelike apatite layer on its surface in the
living body. This apatite layer can be reproduced on its surface even
in a simulated body fluid (SBF) with ion concentrations nearly equal
to those of human blood plasma. In the present study, Ti metal was tre
ated with various NaOH aqueous solutions, and apatite formation on the
resultant metals were examined in SBF. A sodium titanate hydrogel lay
er was formed on the surface of Ti metal, when it was treated with NaO
H solutions with concentrations higher than 0.5 M at 60 degrees C for
periods longer than 24h. Thus treated metals exchanged Na+ ion in the
surface layer for H3O+ ion in SBF to produce a hydrated titania on the
ir surfaces and to increase the degree of supersaturation with respect
to the apatite of SBF. The hydrated titania induced the apatite nucle
ation and the increased supersaturation accelerated the apatite nuclea
tion. Thus formed apatite nuclei spontaneously grow by consuming calci
um and phosphate ions from SBF. These results indicate that bioactive
metal can be obtained by a simple alkali treatment.