The Japanese have developed a tooth-patch made
of an ultra thin bio-compatible film made from hydroxyapatitte, the
main mineral in tooth enamel. The microscopically thin film can coat
individual teeth to prevent decay or to make them appear whiter. It
could also mean an end to sensitive teeth. They are aiming to create
artificial enamel.
Researchers can create film 0.00016 inches thick by firing lasers at
compressed blocks of hydroxyapatite in a vacuum to make individual
particles pop out. These particles fall onto a block of salt which
is heated to crystallize them, before the salt stand is dissolved in
water. The film is scooped up onto filter paper and dried, after
which it is robust enough to be picked up by a pair of tweezers. The
sheet has a number of minute holes that allow liquid and air to
escape from underneath to prevent forming bubbles when it is applied
onto a tooth.
The film is currently transparent, but it is possible to make it
white for use in cosmetic dentistry.
It might be five years before the film could be used in practical
dental treatment such as covering exposed dentin, the sensitive
layer underneath enamel, but it could be used cosmetically within
three years. The technology is currently patented in Japan and South
Korea and applications have been made in the United States, Europe,
and China.