Biomedical Engineering Reference
In-Depth Information
21.8.2 Nanotechnology in Periodontics
Some of the futuristic applications of nanotechnology in dentistry have been outlined as follows.
Freitas has described how medical nanorobots might utilize specific motility mechanisms to crawl
or swim through human body tissues with navigational precision, acquire energy, sense and manipu-
late their surroundings, achieve safe cytopenetration [60] . Functions may be controlled by an onboard
nanocomputer executing programmed instructions in response to local sensor stimuli. Alternatively,
the dentist may issue strategic instructions by transmitting his orders directly to in vivo nanorobots
via acoustic signals (e.g., ultrasound).
21.8.2.1 Local Anesthesia and Hypersensitivity Cure
Colloidal suspension containing millions of active analgesic micron-size dental nanorobots will be
instilled on the patient's gingiva. After contacting the surface of the crown or mucosa, the ambulating
nanorobots will reach the dentin by migrating into the gingival sulcus and passing painlessly through
the lamina propria or the 1-3 μm thick layer of loose tissue at the cemento-dentinal junction. Upon
reaching the dentin, nanorobots enter 1-4 μm diameter dentinal tubule holes and proceed toward the
pulp, guided by a combination of chemical gradients, temperature differentials, and positional navi-
gation, all under onboard nanocomputer control. Assuming a ~10 mm total path length from tooth
surface to pulp, a very modest nanorobot travel speed of 100 μm/s completes the journey into the pulp
chamber in ~100 s. The presence of natural cells that are constantly in motion around and inside the
teeth suggests that such journeys should be feasible.
Once installed in the pulp and having established control over nerve impulse traffic, the analge-
sic dental nanorobots may be commanded by the dentist to shut down all sensitivity in any particu-
lar tooth that may require treatment. When the dentist presses the icon for the desired tooth on the
handheld controller display, the selected tooth immediately numbs. After the oral procedures are com-
pleted, the dentist orders the nanorobots (via the same acoustic data links) to restore all sensation, to
relinquish control of nerve traffic, and to egress from the tooth by similar pathways used for ingress,
followed by aspiration. Reconstructive dental nanorobots would selectively and precisely occlude
selected tubules in minutes, using native biological materials, offering patients a quick and permanent
cure.
21.8.2.2 Natural Tooth Maintenance and Repair
The appearance and durability of tooth may be improved by replacing upper enamel layer with cova-
lently bonded artificial materials such as sapphire or diamond, which have 20-100 times the hardness
and strength of natural enamel. It can be made more fracture resistant possibly including embedded
carbon nanotubes.
Major tooth repair may evolve through several stages of technological development:
l
first using genetic engineering,
l
tissue engineering and
l
later growing whole new teeth in vitro and installing them.
Ultimately, the nanorobotic manufacture and installation of a biologically autologous whole
replacement tooth including both mineral and cellular components (e.g., complete dentition replace-
ment therapy) should become feasible to undertake within the time and economic constraints of an
ordinary office visit, using an affordable desktop manufacturing facility in the dentist's office.
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