Biomedical Engineering Reference
In-Depth Information
intrinsically altering cell behavior both in vitro and in vivo. This is significant for bone and
dentition in that it represents an additional mechanism, beyond mechanical properties, by which
silica-based nanoparticles might be used for therapeutic applications.
4.6.4
Osseointegration
Osseointegration is generally defined as the direct, functional interaction between bone and an
implant
[98]
. This process is particularly important to the fields of dentistry and bone biology
[98,99]
. The response of the bone to the implant can be influenced by a number of factors including
the quality of the bone, surface properties of the implant, as well as topography of the implant
[100]
. Furthermore, deformities caused by injury, disease, or wear in the alveolar process, the ridge
of bone that contains the tooth sockets, present problems associated with implants. In this case,
bone grafts or substitutes are often used to correct the deformities. Although titanium has been the
focus of much of the work-related implants, the physical properties of nanosilica, as discussed
above, suggest that this material could have significant beneficial effects on surface and topography
modification both altering the interface of the implant with bone and cell recruitment as well as
incorporation of bioactive molecules
[100]
. The studies described throughout this chapter suggest
that the use of silica-based nanomaterials on skeletal regulation may also be applicable to the for-
mation and healing/repair of the jaw in preparation of dental implants.
4.6.5
Biocompatibility/toxicology
Although dietary silica is considered generally safe and even beneficial, the nanoscale has the
potential to alter physicochemical properties from the bulk form of any substance. Somewhat
surprisingly, 50 nm silica nanoparticles have been detected to cross the blood
brain barrier in mice
although without apparent negative effects or toxicity
[101]
. The topical nature of many potential
dental applications reduces the potential significance of both the biocompatibility and toxicology
profile of novel silica nanomaterials. Long-term inhalation of silica which can occur by those
involved with various dental procedures such as milling and grinding can cause inflammation and
even silicosis. These silica particles are however generally thought to be larger crystalline forms
(0.5
m). As human applications of nanomaterials move toward bioactively altering or target-
ing cells or the implant
10
μ
bone interface, a more concerted effort to understand the biocompatibility
and/or toxicology of silica-based nanomaterials will be required. The same properties that make
nanoparticles so exciting; size, shape, and surface properties might also alter the biocompatibility
of the resulting novel material.
4.7
Conclusions
Nanotechnology presents many opportunities in dental medicine. Because of the nature of dental
applications, mostly topical with limited systemic exposure, nanotechnology has the potential to
have a much more immediate impact than other fields of medicine. Silica-based nanomaterials are
particularly well suited to dental applications because of the mechanical and esthetic properties.
Additionally, the ease of surface modification, size control, and biocompatibility make silica an
