Biomedical Engineering Reference
In-Depth Information
Bioactive glasses are interesting materials for use as bone grafts, implant coatings, bone cements,
toothpaste, and various other applications in dentistry.
The application of bioactive glass in dentistry began in the mid-1980s when Dr. Clark,
Dr. Stanley, and Dr. Hall tested the bioactive glass and have been successful in preserving the
alveolar ridge in edentulous patients. These results have led to regulatory approval for commercial
use of Bioglass
s
. In this decade, not only the pioneer brand Bioglass
s
but also several new bioac-
tive glass types have been increasingly studied and applied in various areas of dentistry.
Perioglass
s
, for example, is widely used in implant dentistry and periodontics
[4]
.
In the following sections, the impacts and applications in dentistry of this new strategy of devel-
opment of nanoscale bioactive glasses will be discussed. Further research will be presented and the
future of bioactive glass nanoparticles in dentistry will be discussed.
Nanoscale bioactive glasses have been gaining attention due to their reported superior bio-
activity when compared with conventional micron-sized bioactive glass materials. There is evi-
dence in the literature of a more rapid mineralization in bones and teeth when in contact with
bioactive glass nanoparticles
[44]
.
Evidence shows that surface properties of the bioactive glass may affect cellular response.
Bioactive glass on the nanoscale shows excellent properties, such as surface energy, surface wett-
ability, surface topography, and surface chemistry. This improvement
is due to the increased
surface area of the material at the nanoscale.
The events occurring at the interface of bioactive glass with cells attempt to mimic the natural
interaction of cells with extracellular matrix. Biomaterials do not directly interact with living tissue
but with a layer of adsorbed proteins such as fibronectin, vitronectin, fibrinogen, collagen, and
laminins called soluble proteins of the matrix. Cells recognize proteins of the matrix through a
family of cell surface receptors called integrins
[45,46]
. When these receptors are sensed, they
group together and form adhesion complexes that provide anchoring cells to the bioactive glass
surface and unleash subsequent cellular responses. Therefore, the initial interaction of the cell
material is a complex process that begins with the adsorption of proteins followed by adhesion,
spreading, cell differentiation, and ends with the full operation of the cell
[46]
. So the improvement
of surface properties of bioactive glass has a direct influence on the adsorption of specific proteins,
thus causing an increase in bioactivity and biocompatibility of the material.
There are several applications for bioactive glass nanoparticles in dentistry; for example, various
products with bioactive glass nanoparticles have been developed to control the formation of oral bio-
film, such as toothpaste and mouth rinses. These products are designed to decrease bacterial adhesion
thereby reducing the formation of biofilms. Although bioactive glasses have been used in bone re-
generation for many years, only recently studies on their antimicrobial properties have gained focus.
A further application of the antibacterial properties of bioactive glass nanoparticles is in the
endodontic area. Disinfection of a complex root canal system is essential for long-term success in
endodontics. However, even after the chemical and mechanical treatment of the channels is some-
times impossible to achieve complete disinfection. Microbiological studies have demonstrated the
presence of resistant microorganisms such as Enterococcus faecalis and Candida albicans in persis-
tent infections of the channel. Microorganisms remaining in the root canals are the major cause of
treatment failure in the root canal. An ideal drug for endodontic treatment should achieve a wide-
spectrum antimicrobial, be biocompatible, be able to reduce inflammation, and induce repair of
mineralized tissue
[47
50]
.
