Biomedical Engineering Reference
In-Depth Information
24.2.4
Dental durability and cosmetics applications in dentistry
It has been proposed that tooth durability and appearance can be improved by replacing outer
enamel layers with pure nanoscale sapphire and diamonds. These are more fracture resistant with
high strength, possibly by embedding carbon nanotubes
[25]
. Durability and appearance of the
tooth may be improved by replacing upper enamel layers with covalently bonded materials such
as sapphire and diamonds. Nanotechnology has improved the properties of various kinds of fibers
[26]
which can be used in improving cosmetic appearance and also provide a possible alternative
for delayed drug delivery at the site of action in the oral cavity
[27]
. Polymer nanofiber materials
have been explored as drug delivery systems, scaffolds, and filters. Such scaffolds can also be
used as drug delivery scaffolds to deliver osteoinductive and anti-inflammatory drugs. Carbon
nanofibers with nanometer dimensions showed selective increase in osteoblast adhesion necessary
for successful orthopedic/dental implant applications due to a high degree of surface roughness
[27,28]
.
24.2.5
Nanophase alumina for dental applications
Alumina samples (with a nanophase grain size of 23 nm and a conventional grain size of 177 nm)
were synthesized and evaluated for mechanical and cyto compatibility properties. Compared to the
177 nm grain size, the modulus of elasticity of the 23 nm alumina grain size decreased by 70%;
ductility of alumina can, therefore, be controlled and improved through the use of nanophase for-
mulations. Moreover compared to the 177 nm grain-size alumina, osteoblast (the bone-forming
cells) adhesion on the 23 nm nanomaterial increased by 46%. The improved mechanical properties
of nanomaterials, in addition to the biocompatibility of nanophase ceramics, constitute characteris-
tics that promise improved orthopedic/dental implant efficacy. These nanophase alumina can also
be explored for drug delivery locally in oral applications
[8]
.
24.2.6
Nanoparticulate drug delivery in dental applications
Drug delivery scaffolds made of nanomaterials could aid in developing craniofacial tissue as well
as for the delivery of therapeutic drugs following implantation, such as for periodontal disease
treatment with antibiotics
[29]
. Controlled release of drugs or growth factors in vivo is highly
desired to sustain their bioactivity
[30]
Hydrogels such as polyethylene glycol are often used as
drug carriers because drugs can be easily incorporated into the hydrogel solution
[31]
. However,
biodegradable polyesters such as poly(lactic-co-glycolic acid) (PLGA) can be made into nano-
spheres by a double-emulsion technique to achieve significantly longer controlled release compared
with that of hydrogels.
PLGA nanospheres were used to deliver Bone Morphogenetic Protein-7 (BMP-7) to induce
ectopic bone formation
[32]
. Nanospheres were immobilized on the nanofibers of a phase-
separated nanofibrous scaffold without blocking interpore connections. Scaffolds with BMP-7
nanospheres without cells were implanted into rats and evaluated after 3 weeks. Scaffolds soaked
with BMP-7 or with blank nanospheres contained only fibrous tissue, but scaffolds with BMP-7
nanospheres revealed initial bone formation
[32]
. A longer implantation time resulted in more sig-
nificant bone formation in the nanofibrous scaffolds incorporated with BMP-7 nanospheres.
