The health benefits of fluoridated drinking water may be waning as Americans increasingly turn to using toothpastes and mouthwashes that already contain fluoride, a new review suggests.

The research, published Thursday in the Cochrane Database of Systematic Reviews, came to that conclusion after analyzing more than 157 studies that compared tooth decay in kids living in communities that added fluoride to their water supply with communities that didn’t.

Exactly what did the scientists discover?

The studies of more than 5,700 children conducted before fluoride-fortified toothpaste became widely available in the mid-1970s found that adding fluoride to water systems reduced the number of decayed teeth by an average of 2.1 teeth per child.

However, studies conducted after 1975, including nearly 3,000 children in the U.K. and Australia, estimated the benefit was lower, at 0.24 fewer decayed baby teeth per child, just one-quarter of one tooth.

Despite that finding, the researchers stressed municipalities shouldn’t interpret the results as a reason to stop adding the cavity-fighting mineral to their water systems.

“When interpreting the evidence, it is important to think about the wider context and how society and health have changed over time,” study co-author Anne-Marie Glenny, a professor of health sciences research at the University of Manchester in England, said in a journal news release. “Most of the studies on water fluoridation are over 50 years old, before the availability of fluoride toothpaste. Contemporary studies give us a more relevant picture of what the benefits are now.”

Still, hundreds of U.S. communities are now opting out of water fluoridation, NBC News reported, as groups opposed to fluoride in drinking water raise concerns that it may affect children’s IQ levels.

Just last month, a California federal ruled that even though he couldn’t conclude with certainty that fluoridated water was a danger to public health, the U.S. Environmental Protection Agency should strengthen water fluoridation regulations.

About 75% of the U.S. population has tap water with added fluoride at the recommended levels, NBC News reported.

Major public health groups, including the American Dental Association, the American Academy of Pediatrics and the U.S. Centers for Disease Control and Prevention, all maintain their support of fluoridated water.

However, some recent research has hinted that water fluoridation may pose health harms. A study published in May found that women who had higher levels of fluoride during pregnancy said their kids were more likely to have temper tantrums, complain of vague headaches and stomachaches and show other neurobehavioral symptoms by age 3.

Review co-author Janet Clarkson, a professor of clinical effectiveness at the University of Dundee in Scotland, said the new research may serve to “open up a dialogue” to further understand the impact of public water fluoridation.

While water fluoridation helps fight cavities, it doesn’t eliminate the harms of high sugar consumption or poor oral health behaviors, Clark noted in a journal news release.

“It is likely that any oral health preventive program needs to take a multifaceted, multiagency approach,” she added.

More information

The U.S. Centers for Disease Control and Prevention has more on fluoridated drinking water.

SOURCE: Cochrane Review, Oct. 3, 2024; NBC News

Source: HealthDay