The problem with having the treatment in those unenlightened years was that your neighborhood barber-surgeon would file down your teeth and then soak them in a concentrated solution of nitric acid. The procedure would turn them pearly white, all right, but it also destroyed the tooth enamel and led to massive tooth decay, says the weekly magazine, published by the American Chemical Society, the world's largest scientific society.
It may have taken some time, but 21st century dentists with their latex gloves and rubber face masks are using far safer and more effective whitening techniques than their barber-surgeon predecessors. Among their tools are gels, strips and pastes.
The main cause of most tooth discoloration lies just at the surface of the enamel, where red wine, coffee and tea are the culprits, says C&EN. Colored molecules such as tannins and polyphenols, found in these beverages, become absorbed by the enamel's surface. Dark pigments in cigarettes, blueberries and other foods also can be deposited on your tooth enamel. Much of this staining can be brushed away, but over time these compounds can seep into the enamel, where you can't reach them with your brush.
Aging is another major culprit. As we grow older, our teeth gradually turn more yellow. On the other hand, the antibiotic tetracycline can turn children's teeth gray if taken during the early childhood, when tooth enamel has yet to harden completely, C&EN explains. Over time the antibiotic mixes with light and oxygen and gives teeth a grayish-blue tint that's hard to remove.
All toothpastes depend on abrasives to scrub stains from the tooth surface. The first "toothpowder," invented in England in the late 1700s, like the first whi
Contact: Michael Bernstein
American Chemical Society