Mineralization and calcium fixation within a porous apatitic ceramic material after implantation in the femur of rabbits
✍ Scribed by Krajewski, A. ;Ravaglioli, A. ;Mongiorgi, R. ;Moroni, A.
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- English
- Weight
- 949 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Cylinders (0.8 cm long, 1.0 cm of diameter and with an axial hole), constituted, after firing, of a ceramic mixture of hydroxylapatite (HA) and P-tricalciumphosphate (P-TCP) in a 10: 1 ratio, were implanted into mid-diaphiseal defects of one femur of 20 rabbits and stabilized with intramedullary rods. The implantation sites were checked radiographically every month, a n d after 3 m o n t h s (3 a n i m a l s ) a n d 6 months (17 animals) the rabbits were sacrificed and the implants with the surrounding tissue were embedded in methylmetacrylate, cut to thick sections and analyzed by scanning electron microscopy (SEM). Porosimetric and x-rays diffraction analyses were carried out before and after implantation of the cylinders, and the state of mineralization at the bone-implant in-terface was determined by EDAX microprobe analysis. Bony callus formation started at 1 month at the osteotomy sites, a s j u d g e d by radiography, b u t after 3 months a not-mineralized zone had still been demonstrated between bone a n d the implants. At 6 months, 13 implants showed themselves firmly fixed in their implantations beds, while 4 implants were only incorporated at their proximal ends. In bone contact zones, an enrichment of Ca2+ was displayed by microanalytical techniques in the outer zone of the implanted samples which may be explained by an apparent additional phase transformation of HA into TCP, thanks to the change of the Ca/P ratio, that takes place in uizlo.