Biomedical Engineering Reference
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(a)
(b)
Figure 2.7.
TEM micrographs of cow bone apatite (7A) compared to carbonate apatite
precipitated at 37 °C (7B).
2.3.2.3 Simultaneous Incorporation of Carbonate and Fluoride.
Min-
eral (staffellite, marine phosphorites), and biologic apatites (from fossil bones
and teeth, some fi sh enameloids and special shells contain both F
−
and
CO
2−
ions [17,57,59,72,86]. Simultaneous incorporation of carbonate (CO
3
- for - PO
4
)
and fl uoride (F-for-OH) in synthetic apatites is obtained by precipitation or hy-
drolysis methods [64]. The contributions of these ions to the lattice parameters
and dissolution property of F-and CO
3
-containing apatite (CFA) are additive.
Thus, the
a
-axis of CFA is much shorter than that of CHA since the incorpora-
tion of either
CO
2−
and F
−
ions causes contraction of the
a
-axis and CFA is less
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