Cellular Responses to Nanoscale Surface Modifications of Titanium Implants for Dentistry and Bone Tissue Engineering Applications - Emerging Nanotechnologies in Dentistry - page 121

Table 8.4 (Continued)
Implant materials Modiication Animal Models Tissue Responses References

Commercially pure
titanium (cpTi) or
Ti6Al4V

Discrete crystalline
deposition of
calcium phosphate
nanoparticles

Rat Increased in

osteoconduction
as a function of
nanotopography
generated by calcium
phosphate nanoparticles
Induced bone-to-implant
contact (bone ingrowth)
Increased tensile test
resistance

[119,120]

Ti implants H 2 SO 4 /H 2 O 2 mixture

treatment (nanopits
5-50 nm)

Dog Enhanced contact

osteogenesis
More bone-to-implant
contact, percentage of
mineralized bone area

[121]

Ti implants TiO 2 blasted with

and without fluoride
treatment

Rabbit, rat, dog Fluoride-modified Ti

implants demonstrated
a firmer bone anchorage
and greater bone
integration
Accelerated
differentiation
Supported
osteoinduction

[89,122-124]

Ti implants Acid etching, dipping

in an aluminum oxide
solution

Rat Increased bone-to-

implant contact
Increased bone-specific
gene products (e.g.,
sialoprotein, osteocalcin,
osteopontin, osterix,
RUNX-2)

[105,106]

8.4.4 Bioactive Molecules
Besides cell responses such as cell morphology, adhesion, and proliferation, surface modification
of bone implants with nanotopography also affects the cellular production of various bioactive and
signaling molecules. For instance, hemispherical protrusions increased the levels of tumor necro-
sis factor-alpha (TNF-α) and prostaglandin E2 (PGE2) release from osteoblasts [86] . TNF-α has a
role as an inflammatory mediator and assesses the ability to attract many cell types including osteob-
lasts, whereas PGE 2 is the factor that stimulates osteoclasts to begin bone resorption. Prostaglandins
are also important inflammatory mediators. The increased levels of TNF-α and PGE 2 indicate an
increase in osteoblast activity. On rougher nanotopography surfaces, cells release a higher level of
PGE 2 [130] . Osteoblasts also showed an increase in expression of osteopontin and bone sialoprotein
(BSP) due to hemispherical indentations [125] . The presence of the proteins, osteopontin, and BSP