title: Push-out testing and histological evaluation of glass reinforced hydroxyapatite composites implanted in the tibia of rabbits.
abstract: In vitro and in vivo bioactivity studies were performed to assess the biocompatibility of CaO-P2O5 glass-reinforced hydroxyapatite (GR-HA) composites. The ability to form an apatite layer by soaking in simulated body fluid (SBF) was examined and surfaces were characterized using FTIR reflection and thin-film X-ray diffraction analyses. Qualitative histology, histomorphometric measurements, and push-out testing were performed in a rabbit model for characterizing bone/implant bonding. Under the in vitro conditions using SBF, 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 bone, 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.
authors: Laboratório de Biomateriais, Instituto de Engenharia Biomédica, Porto, Portugal.
authors: M A
authors: MA
authors: Lopes
authors: J D
authors: JD
authors: Santos
authors: F J
authors: FJ
authors: Monteiro
authors: C
authors: C
authors: Ohtsuki
authors: A
authors: A
authors: Osaka
authors: S
authors: S
authors: Kaneko
authors: H
authors: H
authors: Inoue
mesh_terms: D000818:Animals; D001826:Body Fluids; D018786:Bone Substitutes; D003188:Composite Resins / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D008297:Male; D019919:Prosthesis Implantation; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D013977:Tibia; D013997:Time Factors
chemical_list: D018786:Bone Substitutes; D003188:Composite Resins; D017886:Durapatite