Biomedical Engineering Reference
In-Depth Information
Surface roughness has been shown to be an infl uencing parameter for cell
response. Bigerele et al. [Bigerele et al., 2002] compared the effect of roughness
organization of Ti-6Al-4V or CpTi on human osteoblast response (proliferation
and adhesion). Surface roughness is extensively analyzed at scales above the cell
size (macro-roughness) or below the cell size (micro-roughness) by calculation
of relevant classic amplitude parameters and original frequency parameters. It
was found that the human osteoblast response on electro-erosion Ti-6Al-4V
surfaces or CpTi surface was largely increased when compared to polished or
machine-tooled surfaces after 21 days or culture, and that the polygonal morphol-
ogy of human osteoblast on these electro-erosion surfaces was very close to the
aspects of human osteoblast
in vivo
on human bone trabeculae. It was concluded
that electro-erosion (creating a rough surface) is a promising method for prepara-
tion of bone implant surfaces, as it could be applied to the preparation of most
biomaterials with complex geometries.
Ti oxide fi lms were synthesized on Ti, Co alloy, and low-temperature isotropic
pyrolytic carbon by the ion beam enhanced deposition technique [Pan et al., 1997].
The amorphous non-stoichiometrical Ti oxide fi lms (TiO
2−
x
) were obtained. Blood
compatibility of the fi lms was evaluated by clotting time measurement, platelet adhe-
sion investigation, and hemoplysis analysis. It was found that the blood compatibility
of the material was improved by the coating of Ti oxide fi lms. The non - stoichiometric
TiO
2−
x
has n-type semiconductive properties because very few cavities exist in the
valence band of TiO
2−
x
; charge transfer is diffi cult from the valence band of fi brinogen
into the material. On the other hand, the n-type semiconductive TiO
2−
x
with a higher
Fermi level can decrease the work function of the fi lm, which makes electrons move
out from the fi lm easily. As a result, it was concluded that the deposition of fi brinogen
can be inhibited and blood compatibility improved.
Favorable wound healing responses around metallic implants depend on
critical control of the surgical and restorative approaches used in dental implant
treatments. One critical parameter that has not been biologically studied is the
role of a clean, sterile oxide surface on an implant. This oxide surface can alter
the cellular healing responses, and potentially the bone remodeling process,
depending on the history of how that surface was milled, cleaned, and sterilized
prior to placement. Phenotypic responses of rat calvarial osteoblast-like cells
were evaluated on CpTi surfaces. These surfaces were prepared to three different
clinically relevant surface preparations (1
m grit sand blast),
followed by sterilization with either ultraviolet light, ethylene oxide, argon
plasma-cleaning, or routine clinical autoclaving. It was found that osteocalcin and
alkaline phosphatase, but not collagen expression, were signifi cantly affected by
surface roughness when these surfaces were altered by argon plasma-cleaning,
and that on a per-cell basis, levels of the bone-specifi c protein, ostocalcin, and
enzymatic activity of alkaline phosphatase were highest on the smooth 1
μ
m, 600 grit, and 50
μ
m
polished surface, and lowest on the roughest surface for the plasma-cleaned CpTi
[Stanford et al., 1994].
Buser et al. [Buser et al., 1991] treated CpTi surface by blasting, acid-
treatment in HCl/H
2
SO
4
, and the HA-coating. It was reported that rough implant
μ
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