Biomedical Engineering Reference
In-Depth Information
[639]. These findings clearly revealed that apatite formation in the
physiological environments could not be confirmed as the common
feature of bioceramics. Nevertheless, for want of anything better,
currently the bioactivity mechanism of calcium orthophosphate
bioceramics could be described by a reasonable combination of Figs.
4.10-4.12, e.g
, by updating the Ducheyne's and Hench's models by 3
initial stages taken from Fig. 4.15.
.
Figure 4.15
A schematic diagram representing the phenomena that occur
on HA surface after implantation: (1) beginning of the implant
procedure, where a solubilization of the HA surface starts;
(2) continuation of the solubilization of the HA surface; (3)
the equilibrium between the physiological solutions and the
modified surface of HA has been achieved (changes in the
surface composition of HA does not mean that a new phase of
DCPA or DCPD forms on the surface); (4) adsorption of proteins
and/or other bioorganic compounds; (5) cell adhesion; (6)
cell proliferation; (7) beginning of a new bone formation; (8)
new bone has been formed. Reprinted from Ref. [636] with
permission.
Figure 4.16
A schematic view of a third generation biomaterial, in which
porous calcium orthophosphate bioceramics acts as a scaffold
or a template for cells, growth factors, etc. Reprinted from Refs.
[43, 56] with permission.
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