Optimum Fluoride Levels For Children's Toothpastes

The levels for fluoride in children’s toothpastes have never undergone a systematic evaluation before, says review co-authors Helen Worthington, Ph.D., and Anne-Marie Glenny, PhD. Worthington is a professor of evidence-based care and Glenny is a senior lecturer in evidence based oral health at the University of Manchester School of Dentistry in England.

The new review, which investigated results from 75 controlled clinical studies, found that the benefits of fluoride are reduced for toothpastes that contain less than 1,000 parts per million of fluoride. Toothpastes with levels in the range of 440 to 550 produce results no better than what is accomplished by toothpaste that does not contain fluoride, Worthington and Glenny say.

The researchers point out the need for balance between the benefits of fluoride in toothpastes and the risk associated with fluorosis caused by over-fluoridation in very young children. The reviewers write: “Most of the available evidence focuses on mild fluorosis. There is weak, unreliable evidence that starting the use of fluoride toothpaste in children younger than 12 months of age might be associated with an increased risk of fluorosis. The evidence for its use between the age of 12 and 24 months is equivocal.”

Many clinical studies in the United States have been done to evaluate the benefits of toothpastes with between 1,000 and 1,100 parts per million of fluoride and most were done with children, said Clifford Whall, PhD, at the American Dental Association (ADA). What no researchers have done previously is systematically review all of the comparative studies on different concentrations of fluoride.

The finding that toothpastes with fluoride concentrations around 400 to 500 parts per million and below are not as effective in preventing tooth decay is not surprising, Whall says.

Not all U.S. toothpaste brands contain fluoride. However, those toothpastes that do are required by the U.S. Food and Drug Administration to have at least 1,000 parts per million. Toothpastes in the United Kingdom and Europe have levels of fluoride above and below 1,000 parts per million, according to Worthington and Glenny. Some have as much as 1,500 parts per million of fluoride, but some children’s toothpastes contain levels as low as 250 parts per million.

A large variety of toothpastes containing fluoride is available in the United States, Whall said. “Toothpastes with the ADA Seal of Acceptance have undergone a rigorous independent scientific review of safety and effectiveness, and do what they say they do on the label.” About 60 toothpaste products in the United States have the seal, he said.

The vast majority of cases of fluorosis seen in the United States are usually so mild that only a dentist would be able to identify the problem, Whall said. Mild fluorosis has no effect on tooth function, he said. “In fact, a recent study has indicated that teeth with mild fluorosis are even more resistant to tooth decay.” Fluorosis can occur when children ingest too much fluoride, for example by swallowing fluoride-containing toothpaste or inappropriate use of prescribed fluoride supplements.