Even celebs have teeth problems. See actor Tom Cruise's invisible ceramic braces. Many teenagers cringe at the prospect of braces. Getting one's teeth in order used to mean enduring a mouth full of metal, but not so anymore. Invisible braces hit the market in 1987, and now there are multiple brands.
Invisible braces are made of translucent polycrystalline alumina (TPA). A company called Ceradyne developed TPA in conjunction with NASA Advanced Ceramics Research to protect the infrared antennae of heat-seeking missile trackers.
In the meantime, another company, Unitek, was working on a new design for dental braces -- a design that would be more aesthetically pleasing and would not have the shiny metallic factor. It discovered that TPA would be strong enough to withstand use and is translucent, making it a prime material for invisible braces. Because of their instant popularity, invisible braces are one of the most successful products in the orthodontic industry [source: NASA Scientific and Technical Information].
