- Watch what you bite: Enamel, the sturdiest substance in the body, is harder than a copper bullet but slightly less hard than a stainless-steel fork.
- Enamel also develops tiny cracks that diffuse the stress of chewing and help prevent breaks. Aerospace engineers are studying this feature with an eye toward creating stronger spacecraft.
- Yet your teeth cannot always stand up to your mouth's native population of bacteria, which produce acids that leach calcium and phosphate from the enamel - the process that leads to cavities.
- Nothing personal: Those acids are an accidental by-product created when the bacteria digest sugars in the food you've eaten. (Before the invention of refined sugar, cavities were rare.)
- Fluoride counters tooth decay by preventing the loss of minerals from enamel and promoting reabsorption of calcium and phosphate from saliva into the enamel.
- In 1945, Grand Rapids, Michigan, became the first community in the world to put fluoride into its water system. Today, two-thirds of U.S. residents get fluoridated water.
- The next stage in fighting tooth decay? Jeffrey Hillman, professor emeritus of oral biology at the University of Florida, has begun human trials of a genetically engineered version of the oral bacterium Streptococcus mutans, which he modified to produce less acid.
- This strain also creates an antibiotic that kills other S. mutans strains, allowing it to take over inside the mouth.
- A study by researchers at Yale and New York University has confirmed a bit of folk wisdom: The more children a woman has, the more likely she is to have missing teeth.
- Possible explanation: Pregnant women tent to develop gingivitis (inflammation of the gums) as hormonal shifts make the tissues more sensitive to irritation.
*Source: Discover Magazine
