INTERFACE MECHANICS AND HISTOMORPHOMETRIC ANALYSIS OF HYDROXYAPATITE-COATED AND POROUS GLASS-CERAMIC IMPLANTS IN CANINE BONE

A canine study was performed to make a histological and biomechanical evaluation of the interface between bone and two different bioceramic implants. A newly developed glass-ceramic formed by P2O5, CaO, SiO2, a nd Al2O3, giving a crystal phase composed of CaP2O6-AlPO4-SiP2O7, was compared to hydroxyapatite (HA) coated Ti-6Al-4V implants. A total of 24 implants were inserted into the femoral condyle of 15 adult female golden retriever dogs weighing 20-25 kg. There was a 12 week follow-up . Implants were examined by mechanical testing, histology, histomorpho metry, microradiograpic methods, and EDAX analysis. The ultimate shear strength for the HA-coated implants was significantly higher than in the glass-ceramic group. When these values were related to the histomo rphometric measurements, the difference could be explained by the tiss ue-to-implant contact. The glass-ceramic showed direct contact only wi th nonmineralized, osteoid bone. The HA-coated implants, however, were integrated into the bone. The study indicated that porous glass-ceram ic containing AlPO4 causes local osteomalacia and might not be suitabl e for clinical purposes. (C) 1995 John Wiley & Sons, Inc.