Study Questions Benefits of Fluoride in Drinking Water at Preventing Tooth Decay

Widespread use of fluoride in toothpaste may have reduced the value of adding the mineral to tap water.

Although fluoride has been added to drinking water for decades, the findings of a new study suggests that it may not provide children with the same dental benefits it once did.

Fluoride is a naturally occurring mineral that is known to strengthen teeth and gums. For this reason, health experts have recommended that communities add the mineral to drinking water since the 1950s, after studies demonstrated a significant reduction in childhood tooth decay from drinking water enriched with fluoride.

However, recent research has associated fluoride with various health issues, including concerns that the currently approved levels of fluoride in water may lower children’s IQ. This recently led a California judge to order the U.S. Environmental Protection Agency (EPA) to review safe fluoride levels in tap water.

Amid these growing concerns, a study published this month in the medical journal Cochrane Database of Systematic Reviews suggests that the benefits children now received from drinking fluoridated water may not be as substantial as they once were, largely due to the widespread use of fluoridated toothpaste.

The study was conducted by a team of researchers led by Anne-Marie Glenny, of the University of Manchester in the U.K., finding that data published since 1975 shows little improvement in preventing tooth decay among children exposed to drinking water with fluoride added.

The researchers concluded that this shift can be attributed to the increased use of fluoride in toothpaste over the past decades.

Glenny’s team looked at data from 21 studies on how adding fluoride to community water affects children’s tooth decay, and one study on stopping fluoride use.

By analyzing data on over 3,000 children from the U.K. and Australia since 1975, researchers observed an average reduction of 0.24 decayed teeth per child compared to before 1975, when fluoride was not commonly used in toothpaste.

Additionally, the study found insufficient evidence to determine whether fluoridated water significantly reduces tooth decay in the permanent teeth of children or adults.

The team further reviewed 135 additional studies on links between fluoride in water and dental fluorosis, which is a harmless condition where white or brown specks appear on a person’s teeth from the overconsumption of fluoride in childhood.

This research showed that adding fluoride to water at the current limit of 0.7 mg/L causes about 40% of people to develop dental fluorosis. However, only 12% of those will have it at a noticeable or bothersome level.

Glenny indicated that her findings are insufficient to determine if water fluoridation is actually helpful with regard to tooth decay. Her conclusion was that this research shows there is no reason to stop adding fluoride to community water supplies, despite evidence showing a decrease in benefits since the widespread use of fluoridated toothpaste.