M. Neo et al., ULTRASTRUCTURAL-STUDY OF THE A-W GC-BONE INTERFACE AFTER LONG-TERM IMPLANTATION IN RAT AND HUMAN BONE, Journal of biomedical materials research, 28(3), 1994, pp. 365-372
The interface between apatite- and wollastonite-containing glass-ceram
ic (A-W GC) and bone after long-term implantation was studied by scann
ing and transmission electron microscopy (SEM and TEM) using rat and h
uman specimens. First, particles of A-W GC (100-220 mu m in diameter)
were implanted into rat tibiae, and specimens were prepared for observ
ation at 24, 48, 72, and 96 weeks after the operation. These long-term
specimens showed an A-W GC-bone interface different from that at an e
arlier stage, which was investigated in our previous studies. SEM show
ed that the Ca-P-rich layer was wider, suggesting that leaching of ion
s from the A-W GC had continued even after bonding with bone. In some
regions, the material particles were evidently replaced by the bone. T
EM showed that the intervening apatite layer had become indistinct, an
d that A-W GC had intermingled with bone at the interface. In some reg
ions, the surface of the A-W GC was degraded. These findings suggest t
hat the surface region of A-W GC is slowly replaced by bone. Second, a
human bone specimen, which included A-W GC particles (300-700 mu m in
diameter) implanted as a bone filler for about 75 weeks was harvested
and investigated. Excellent A-W GC-bone bonding was observed, and the
ultrastructure of the interface was similar to that in rats after lon
g-term implantation. This finding demonstrated that A-W GC possibly wo
rked in human bone in the same way as in rat bone, showing excellent b
ioactivity. (C) 1994 John Wiley and Sons, Inc.