Biomedical Engineering Reference
In-Depth Information
Figure 4.9
A typical microstructure of calcium orthophosphate cement
after hardening. The mechanical stability is provided by the
physical entanglement of crystals. Reprinted from Ref. [2] with
permission.
All calcium orthophosphate cements and concretes are
biocompatible, bioactive and bioresorbable. The first animal study
of a calcium orthophosphate cement was performed in 1991.
That time a cement consisting of TTCP and DCPA was investigated
histologically by implanting disks made of this cement within the
heads of nine cats [523, 524]. In 1996, that formulation received
an approval by the US Food and Drug Administration (FDA), thus
becoming the first commercially available calcium orthophosphate
cement for use in humans [517]. As the structure and composition of
the hardened cements is close to that of bone mineral, the material
of the hardened cements can easily be used by bone remodeling
cells for reconstruction of damaged parts of bones [156, 514-517].
A possibility to be injected (a minimally invasive technique), a low
setting temperature, an adequate stiffness, an easy shaping and a
good adaptation to the defect geometry are the major advantages
of calcium orthophosphate cements and concretes, when compared
to the prefabricated bulk bioceramics and porous scaffolds. Further
details on this subject are available in Chapter 5 of this topic.
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