Biomedical Engineering Reference
In-Depth Information
the material surface also creates nanoscale topography that is popular among
current dental implant investigators. Treatment with NaOH catalyzes the
production of titanium nanostructures outward from the titanium surface
142
producing a sodium titanate gel layer on the Ti surface while treatment with
H
2
O
2
produces a titania gel layer. The gel-like layer over the titanium mate-
rial allows HA deposition which had been observed with other metals such as
zirconium and aluminum.
143-145
Nanotopography had been created by chemical treatments (peroxidation
with H
2
O
2
, heat, or acid oxidation, such as hydrofluoric acid).
144,145
It has been
observed that novel nanostructures of amorphous titanium oxide formed on the
implant surface with the use of H
2
O
2
with acid etching.
146
Increased adsorp-
tion of RGD peptides were observed after treatment of the implant surface with
H
2
O
2
/HCl, followed by passivation (30% HNO
3
) and heat treatment of the sur-
faces.
147
These treatment processes also increased the mineralization in the same
order while hydrofluoric acid treatments created discrete nanostructures on TiO
2
grit-blasted surfaces.
148
Different reports including cell culture studies,
149,150
preclinical investigations,
151,33
and clinical studies
41
indicated that hydrofluoric
acid treatment of TiO
2
grit-blasted titanium implants is associated with rapid
bone accrual at the implants surface. However, further investigation must be
performed to study the complex chemical changes induced by these methods.
Deposition of nanoparticles onto the titanium surface is another approach
to impart nanofeatures to a titanium dental implant.
32
Deposition of nanometer-
scale calcium phosphate to the implants surface can be achieved through sol-gel
transformation techniques.
152,153
Materials such as alumina, titania, zirconia,
and others can also be applied.
39
As a result of their resultant atomic-scale inter-
actions, the nanomaterial buildup display strong physical interactions.
32,154,30,155
Nishimura and colleagues
156
recently demonstrated a revised directed approach
to the assembly of CaPO
4
nanofeatures on dual acid-etched cpTitanium implant
surfaces. Using a rat model, the deposition of discrete 20- to 40-nm nanopar-
ticles on an acid-etched titanium surface led to increased mechanical interlock-
ing with bone and the early healing of bone at the endosseous implant surface.
Nanotopography has been shown to influence cell adhesion, proliferation,
differentiation, and cell-specific adhesion. Related changes in chemistry and
nanostructure impart important chemical changes and permit biomimetic rela-
tionships between alloplastic surfaces and tissues. It is speculated that alloplas-
tic nanosurfaces possess topographic elements scaled to naturally occurring
substrates.
Ueno introduced nanopolymorphic features of alkali- and heat-treated
titanium surfaces, comprising of tuft-like, plate-like, and nodular structures
that are smaller than 100 nm and determined whether and how the addition of
these nanofeatures to a microroughened titanium surface affect bone-implant
integration.
157
Comprehensive assessment of biomechanical, interfacial, and
histological analyses in a rat model was performed using machined surfaces
without microroughness, sandblasted-microroughened surfaces, and micro-nano
