Biomedical Engineering Reference
In-Depth Information
changes include enhanced wettability, altered protein adsorption, and
potential mineralization phenomenon [89]. Changes in wettability
and altered protein adsorption lead to altered cell adhesion, likely
involving both integrin and non-integrin receptors. The potential for
mineralization and epitaxic crystal growth in support of early bone
bonding could dramatically alter the biomechanical environment of
the healing implant in favor of stability.
Various reports support the concept that nanotopography
enhances osteoblastic differentiation which could also promote
stability and favorably alter the biomechanical environment for
healing [89]. However, initial clinical stability may require additional
considerations of micron-scale topography and overall implant
design. The pioneering investigations of Meirelles and coworkers
suggest that nanometer-scale topography alone is not suficient
to assure robust osseointegration [87, 88]. Investigations which
have isolated nanometer-scale topography as an experimental
variable in osseointegration have required additional consideration
of endosseous implant stability. It is possible that micron-level
roughness is of additional value to the process of osseointegration
[89].
12.3.2
Osteoblastic Cell Behavior on Nanostructured
Surface of Metal Implants
The effect of nanotopography on osteoblastic cell behavior has been
reported in the literature [19, 32, 77, 81, 85, 98, 100, 102, 114, 131].
Surface modiications at the nanometric scale may promote protein
adsorption, cell adhesion and thus favor the osseointegration of
metal implants. Chemical composition, surface energy, roughness,
and topography are key factors for interaction with biological luids,
cells and tissues, and the modiication of one of these parameters
usually modiies the others.
In the ield of dental implants, surface roughness has often been
modiied in order to control bone tissue apposition [9, 37, 76]. Surface
roughness may be divided into three levels according to the scale of
the features: macro-, micro- and nanometer-sized topologies. The
macrostructure of implants has been adapted for primary anchorage
of implants to bone in relation to the biomechanics of the skeleton.
Most implant surfaces usually present a moderately rough surface in
the micrometer range with R a (Roughness average) values around
 
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