The first fluoridated toothpaste, Crest, was introduced in 1955.Fluoride opponents, such as the Fluoride Action Network, cite studies showing that high levels of fluoride have been linked to a number of negative health effects like bone fractures, thyroid disorders and impaired brain development and function.As of 2010, 41 percent of kids ages 12 to 15 had some form of dental fluorosis, according to the CDC.

fluoridating-31

One study published in the fall of 2012 in the journal Environmental Health Perspectives found a link between high fluoride levels found naturally in drinking water in China and elsewhere in the world, and lower IQs in children.

The paper looked at the results of 27 different studies, 26 of which found a link between high-fluoride drinking water and lower IQ.

Tooth decay has declined in the United States since fluoridation began, according to the CDC.

However, it has also declined in other countries that do not fluoridate, according to the World Health Organization (WHO).

Naturally occurring fluoride concentrations in surface waters depend on location but are generally low and usually do not exceed 0.3 ppm. Department of Health and Human Services issued a recommendation for the optimal fluoride level that should be in drinking water to prevent tooth decay.

Groundwater can contain much higher levels, however. This new recommendation is for a single level of 0.7 milligrams of fluoride per liter of water, opposed to the 0.7 to 1.2 milligrams per liter recommendation issued in 1962, which is now the standard.

and will simultaneously reduce the risk of dental fluorosis in younger patients," Edward H.

Moody, Jr., a dentist and president of the American Academy of Pediatric Dentistry (AAPD), told Live Science.

By replacing the hydroxyl molecule on hydroxylapatite, fluoride makes the tooth more resistant to acid attack from bacteria.