Biomedical Engineering Reference
In-Depth Information
progress in tissue repair and regeneration. With the help of nanotechnology it is possible to interact
with cell components, to manipulate cell proliferation and differentiation, and in the production and
organization of extracellular matrices. New nanomaterials are leading to a range of emerging dental
treatments that utilize more biomimetic materials that closely duplicate natural tooth structure. The
uses of nanostructures that will work in harmony with the body's own regenerative processes are
moving into dental clinical practice. In this chapter, we will focus on the recent progress of the
applications of nanotechnology in dental tissue regeneration, the contributions of these new tech-
nologies in the development of innovative biomimetic materials and their potential clinical
applications.
20.2
Nanotechnology for craniofacial bone and
cartilage tissue engineering
Craniofacial bone defects secondary to trauma, infection, cancer, and congenital disorders represent
a major health problem. Current strategies aimed at replacing bony defects include the utilization
of autografts, allografts, and synthetic biomaterials. Despite the fact that these substitutes restore
stability and function to a reasonable degree, however, they still have limitations. Tissue engineer-
ing is considered as an optimal approach for various tissue repairs including craniofacial defect
repair
[4]
. Biomaterials, acting as scaffolds for tissue engineering, play an essential role in the pro-
cess of tissue regeneration. Moreover, incorporation of nanotechnology into scaffold design and
manufacture will further enhance the quality and function of regenerated tissues. Due to the biomi-
metic features and excellent physicochemical properties, nanomaterials have been shown to
improve adhesion, proliferation, and differentiation of cells, which would finally guide tissue regen-
eration (
Figure 20.1
)
[5]
.
Within the craniofacial tissue engineering field, the major types of materials used are natural
and synthetic polymers, ceramics, composite materials, and electrospun nanofibers. Synthetic and
natural polymers are excellent candidates for bone/cartilage tissue engineering application due to
their biodegradability and ease of fabrication. Numerous studies have shown successful bone
formation with nanofibrous synthetic and natural polymer scaffolds such as electrospun poly-
caprolactone
[6]
, poly(lactic-co-glycolic acid) (PLGA)
[7]
, polyvinyl alcohol/type I collagen blend
[8]
, and many others
[9]
. Nanofibrous scaffolds would be an advantageous microenvironment for
bone tissue formation by mimicking the type I collagen fibers that are a major component of bone
and provide a cellular platform for bone formation
[10]
.
Nanophase ceramics are popular as bone substitutes, coatings, and filler materials due to their
dimensional similarity to bone/cartilage tissue and unique surface properties including surface
topography, surface chemistry, surface wettability, and surface energy. Numerous in vitro studies
have revealed that nano-hydroxyapatite (HA) significantly enhances osteoblast adhesion and func-
tion
[11
13]
. In vivo studies have also demonstrated that nanostructured HA can improve cell
attachment and mineralization suggesting that nanosized HA may be a better candidate for clinical
use in terms of bioactivity
[14
19]
. In general, nanostructured ceramics offer much improved per-
formances compared to their larger particle-sized counterparts due to their huge surface-to-volume
