Abstract
Mechanical alloying has been used successfully to produce
nanocrystalline powders of hydroxyapatite (HA) using three different
procedures. The milled HA was studied by X-ray diffraction, Infrared,
Raman scattering spectroscopy and Scanning Electron Microscopy (SEM). We
obtained HA with different degrees of crystallinity and time of milling.
The grain size analysis through SEM and XRD shows particles with
dimensions of 36.9, 14.3 and 35.5 nm (for (R1), (R2) and (R3),
respectively) forming bigger units with dimensions given by 117.2, 110.8
and 154.4 nm (for (R1), (R2) and (R3), respectively). The
Energy-Dispersive Spectroscopy (EDS) analysis showed that an atomic ratio of Ca/P= 1.67, 1.83 and 1.50 for reactions (R1), (R2) and (R3),
respectively. These results suggest that the R1 nanocrystalline ceramic
is closer to the expected value for the ratio Ca/P for hydroxyapatite,
which is 513 congruent to 1.67. The bioactivity analysis shows that all
the samples implanted into the rabbits can be considered biocompatible,
since they had been considered not toxic, bad not caused inflammation
and reject on the part of the organisms of the animals, during the
period of implantation. The samples implanted in rabbits had presented
new osseous tissue formation with the presence of osteoblasts cells. (C)
2004 Elsevier B.V. All rights reserved.
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