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| A flossing demonstration (Associated Press photo: Julio Cortez) |
Flossing might help you have better oral health. But there's no proof of it , despite decades of recommendations by dental experts , the federal government and , yes , manufacturers of floss.
Federal advice is supposed to be based on scientific evidence , so Jeff Donn of
The Associated Press asked federal agencies for the evidence. They didn't reply immediately , but when they issued their latest dietary guidelines this year , "the flossing recommendation had been removed , without notice ," Donn
reports. "In a letter to the AP , the government acknowledged the effectiveness of flossing had never been researched , as required."
Donn examined "the most rigorous research conducted over the past decade , focusing on 25 studies that generally compared the use of a toothbrush with the combination of toothbrushes and floss ," he writes. "The evidence for flossing is 'weak , very unreliable ,' of 'very low' quality , and carries 'a moderate to large potential for bias.'"
Flossing is often cited as a way to remove plaque , but "The majority of available studies fail to demonstrate that flossing is generally effective in plaque removal ," said a review conducted last year. "One study review in 2011 did credit floss with a slight reduction in gum inflammation — which can sometimes develop over time into full-fledged gum disease ," Donn reports. "However , the reviewers ranked the evidence as 'very unreliable.' A commentary in a dental magazine stated that any benefit would be so minute it might not be noticed by users."
Wayne Aldredge , president of the
American Academy of Periodontology , "acknowledged the weak scientific evidence and the brief duration of many studies ," Donn writes. "In an interview at his private practice in New Jersey , he said that the impact of floss might be clearer if researchers focused on patients at the highest risk of gum disease , such as diabetics and smokers. Still , he urges his patients to floss to help avoid gum disease." He told Donn , "It's like building a house and not painting two sides of it. Ultimately those two sides are going to rot away quicker."
"Aldredge also said many people use floss incorrectly , moving it in a sawing motion instead of up and down the sides of the teeth ," Donn reports. "Floss can occasionally cause harm. Careless flossing can damage gums , teeth and dental work. Though frequency is unclear , floss can dislodge bad bacteria that invade the bloodstream and cause dangerous infections , especially in people with weak immunity , according to the medical literature."
But Tim Iafolla , a dentist with the
National Institutes of Health , told Donn that Americans should still floss: "It's low risk , low cost. We know there's a possibility that it works , so we feel comfortable telling people to go ahead and do it."
