Scientists Say: Fluoride

Fluoride (noun, “FLOOR-ide”)

Fluoride is an electrically charged form of the element fluorine.

An atom that carries such an overall charge is called an ion. Fluoride is a negative ion with a -1 charge. That’s because each fluoride ion contains nine (positively charged) protons and 10 (negatively charged) electrons.  

Fluoride strengthens the enamel that makes up the outer layer of our teeth. That makes it an important component of toothpastes and other dental products. Many places also add fluoride to their drinking water. They don’t add much. The recommended level is just three drops of fluoride per 200 liters of water. But even that amount can reduce dental cavities by about 25 percent. That’s according to the U.S. Centers for Disease Control and Prevention (CDC).

In 1945, Grand Rapids, Mich., became the first city to add fluoride to its water. By 2015, about three-quarters of Americans had access to tap water that strengthens teeth. The CDC lists fluoride-treated water as one of the 10 great public health achievements of the 20th century.

Fluoride strengthens enamel thanks to its excellent ability to snag positively charged particles. Compared to other atoms or ions, a fluoride particle is tiny. That means all its negative charge is packed into a small area. In other words, fluoride comes with high charge density. And that allows it to form strong bonds with other particles.

Fluoride binds and holds onto positively charged particles, such as calcium ions. In our mouths, this process forms calcium-based minerals that reinforce enamel. That provides a barrier against acids that would dissolve our teeth.

In a sentence

When fluoride-amended water treatments drop, dental problems rise.

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