Biomedical Engineering Reference
In-Depth Information
Another procedure is allograft, which is made between different individuals of the same species.
However, this procedure also has limitations such as need for donors and the possible transmission
of antigenic proteins among others. Another alternative that has been widely used is the use of allo-
plastic material, and among them bioactive glass is one of the most researched.
Bone tissue is a complex of organic and inorganic materials organized in a global architecture
of several length scales, including the nanoscale. Therefore, the applications of glass nanoparticles
in bone grafts have the dual aim of improving the mechanical properties as well as incorporating
nanotopographic features that mimic properties of bone.
The purpose of tooth replacement is the restoration of function and esthetics without affecting
the mineralized structures and soft tissues of the oral cavity. One of the challenges in implantology
is to achieve and maintain the osseointegration as well as the epithelial junction of the gingival
tissue with implants
[59]
. Bone regeneration is required for many clinical issues in the dental area.
The autogenous graft is always a choice, but sometimes the host tissue is thin and cannot be mod-
eled with the desired shape.
Metals and alloys have wide application in the area of implant dentistry, and the most
commonly used are titanium alloys. Titanium implants have excellent mechanical properties,
but do not exhibit bioactivity; that is, they are not capable of binding to the living tissue. Unlike
them, bioactive glasses are able to cause specific biological responses. Therefore, coating of
implants with bioactive glasses is a way to combine good titanium mechanical properties and bio-
activity of the glasses. Various techniques for surface treatment are applied to modify the surface
of titanium.
Many studies have shown that implants coated with bioactive glasses have a higher rate of inte-
gration and increased bone fixation, faster when compared with uncoated implants
[60,61]
.
Development of new technologies is also very important to improve the properties and applications
of biomaterials. Application of bioactive glass coatings using nanoparticles is a promising alterna-
tive for increasing the interaction of glass with the implant surface.
The bioactive glass material is one of the most studied and widely used to treat bone periodontal
defects due to its bioactive properties, so in the next section this topic will be discussed more
extensively.
15.5
Bioactive glass nanoparticles in periodontal regeneration
Periodontium is a complex structure, consisting of epithelial tissue (gum) and connective (periodon-
tal ligament) and mineralized tissue (cementum and alveolar bone) (
Figure 15.6
). To achieve suc-
cess in periodontal therapy, the sealing of the junctional epithelium, the insertion of new
connective tissue fibers, the formation of new cementum, and the alveolar bone restoration are
needed. The main aims of periodontal therapy are to eliminate the disease by infection control and
correct anatomical defects through regeneration of the tissues supporting the teeth.
Although Hench started to develop bioactive glass in 1969, only from the 1990s that material
was first applied in studies 'in vivo' in periodontal lesions. These studies evaluated histological
efficacy of bioactive glass, and the results were positive compared with conventional treatments
[62]
. At
this time, bioactive glass was clinically approved for use both in dense form—for
