Everyone who has ever seen a toothpaste commercial knows that fluoride is the ingredient that helps fight tooth decay, but a new review has determined exactly how much fluoride is best in toothpastes for children.
For optimal prevention of cavities in children over age 6, toothpastes should contain at least 1,000 parts per million of fluoride. Preventing cavities can help reduce the need for extensive and costly dental treatments, including extractions.
The levels for fluoride in children's toothpastes have never undergone a systematic evaluation before, said 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 review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews like this one draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The new review, which examined 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 lower fluoride levels — in the 440 to 550 range — give results that are no better than the results seen with toothpaste that does not contain fluoride, Worthington and Glenny said.
Scientists made the link between fluoride and reduced tooth decay in the 1930s, the reviewers say, and adding fluoride to toothpastes and other oral hygiene products reduces the incidence of cavities and tooth decay by about 24 percent on average.
However, fluoride has a downside. Toothpastes with concentrations greater than 1,000 parts per million of fluoride increase the risks of fluorosis — a condition that can cause white streaks and spots or stained teeth — especially when they are used by children under the age of 5 or 6 years. In older children with fully developed teeth, the risks of fluorosis due to fluoride toothpastes are reduced and the benefits of reducing the risk of cavities and tooth decay are clear, Worthington and Glenny say.
There must be a balance between the benefits of fluoride in toothpastes and its risks in very young children who are developing their adult teeth, the reviewers wrote: "Most of the available evidence focuses on mild fluorosis. There is weak, unreliable evidence that starting the use of fluoride toothpaste in children under 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, Ph.D., 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 said.
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.
The ADA recommends the use of toothpastes with fluoride for older children and adults. "Children under age two should not use fluoride toothpaste unless a dentist recommends it," Whall said.
Children's toothpastes that have earned the ADA Seal of Acceptance include Crest Kids SparkleFun Cavity Protection Gel, Aquafresh for Kids Toothpaste, Colgate for Kids Toothpaste and Tom's of Maine Natural Fluoride Toothpaste for Children.
"You have to be careful with children," Whall said. Parents should tell children under age 6 to put a pea-sized amount of toothpaste on their brush. Children should be supervised while they brush their teeth to make sure they are not swallowing the paste.
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