1,721,084 research outputs found
An HA-chamber for biomaterial evaluations: first results
No full textAn hydroxyapatite (HA) cylindrical chamber, containing a vessel pedicle surrounded by autologous bone and/or HA spherules, was placed in each medial right thigh of 15 New Zealand male rabbits for 3 months. Results show the displacement of chambers from the original position, several new formed blood vessels, erosion of the bone graft, with living osteocytes inside, and a little osteoclast aggression of HA spherules. New bone has formed both on bone graft and HA spherules, whereas no bone formation was detected when HA spherules were the only graft used. In conclusion, the results confirm the osteoconductive features of the used HA, highlight the effectiveness of the HA chamber and some critical aspects which can be improved to obtain the best effects
Interfacial study of some inert and active ceramics implanted in bone
No full textCylinders of biologically inert (Alumina and Zirconia) and active (Hydroxyapatite, Bioglass and AKRA 15 glass) ceramics, were inserted as a press-fit for 6 and 12 months in the femurs of adult Merinos sheep. It resulted that all the cylinders were surrounded by an envelope of new cortical bone; however those made up of inert ceramic were separated from the bone by a capsule of loose connective tissue, whereas a direct contact occurred between the new formed bone and the active ceramics cylinders, except for AKRA 15 rods whose surfaces appeared to be almost compietely covered by fibrous tissue. A bidirectional flow of ions occurred in the outer reactive layer of the two glasses examined. The results are discussed in relation with the biological behaviour of the tested materials in bone implants
Study on short-term implants of a fluorinated glass in bone
No full textThe behaviour of a proposed fluorinated glass implanted in femurs of rabbits for a short time was studied on contact microradiographs by electron microscopy and X-ray microprobe. The glass appeared to be surrounded by several bony trabeculae starting from the endosteal surface; some trabeculae were in contact with the outer part of the glass, X-ray analysis showed that degradation occurs in the outer layer only, although without uniformity. Si-rich zones were randomly located in the deeper part of the layer that externally formed zones with P and Ca content higher than that in the non-implanted glass
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