Biomedical Engineering Reference
In-Depth Information
Figure 9.32
Comparisons of the bone to metal contact (BMC) in all
threads of control and test S, P and, Ca implants after 6 weeks
of healing time (*P <
0.005) [81].
Sul [81] shows that the electrochemically oxidized nanoporous
Ca-containing implant demonstrated the strongest bone response
regarding removal torque test and histomorphometrical
quantiications between the four groups. S and P implants also showed
signiicantly stronger bone tissue reactions than the controls. The
improved bone reactions of S-contained implants are most likely
due to the topographical properties (porous structure) while the
strong bone reactions of P and Ca implants may be attributed to the
chemical properties [81]. Electrochemically oxidized implants of
200 nm or less oxide thickness showed no signiicant differences in
bone response in comparison to controls but implants with
600 nm or more oxide thickness showed a signiicantly enhanced
bone response in a rabbit model [81]. For obtaining thick micro-
meter anodic oxide layer, phosphoric/sulphuric acid electrolytes are
deinitely useful.
Ds
et al
. [14] investigated
in vitro
cell-materials interactions
using human osteoblast cells on the anodized titanium in H
2
SO
4
, HF
and H
3
PO
4
electrolytes at anodizing voltage of 20 V. Figures 9.33 and
9.34 show the SEM images of the cell morphologies on Ti-control
(without oxidation) and anodized surfaces after 3 and 11 days of
cell culture, respectively. Cells on Ti-control (Fig. 9.33a) show an
elongated, lattened morphology. Cells on the H
2
SO
4
anodized surface
show a rounded morphology (Fig. 9.33b), whereas on the H
3
PO
4
oxidized surface, they show good cell attachment (Fig. 9.33c). The
HF anodized surface is uniformly covered with cells and ilopodia
extensions were observed (Fig. 9.33d). After 11 days of culture, the
cells on the Ti-control surface have lattened elongated morphology
