Ma. Lopes et al., Push-out testing and histological evaluation of glass reinforced hydroxyapatite composites implanted in the tibia of rabbits, J BIOMED MR, 54(4), 2001, pp. 463-469
In vitro and in vivo bioactivity studies were performed to assess the bioco
mpatibility of CaO-P2O5 glass-reinforced hydroxyapatite (GR-HA) composites.
The ability to form an apatite layer by soaking in simulated body fluid (S
BF) was examined and surfaces were characterized using FTIR reflection and
thin-film X-ray diffraction analyses. Qualitative histology, histomorphomet
ric measurements, and push-out testing were performed in a rabbit model for
characterizing bone/implant bonding. Under the in vitro conditions using S
BF, an apatite layer could not be formed on GR-HA composites within 8 weeks
. Results of push-out testing showed bonding between the composites and bon
e, ranging from 130-145 N after 2 weeks of implantation. After the longest
implantation period, 16 weeks, the GR-HA composite prepared with the higher
content of CaO-P2O5 glass showed the highest bonding force, 606 +/- 45 N,
compared to 459 +/- 30 N for sintered HA. Development of immature bone and
modifications in the turnover of a more mature bone on the surface of GR-HA
composites were similar to those on sintered HA. (C) 2000 John Wiley & Son
s, Inc.