It’s one of the most universal recommendations in all of public health: floss daily to prevent gum disease and cavities.
Except there’s little proof that flossing works.
Still, the federal government, dental organizations and manufacturers of floss have pushed the practice for decades. Dentists provide samples to their patients; the American Dental Association insists on its website that, “Flossing is an essential part of taking care of your teeth and gums.”
The federal government has recommended flossing since 1979, first in a surgeon general’s report and later in the Dietary Guidelines for Americans issued every five years. The guidelines must be based on scientific evidence, under the law.
Last year, the Associated Press asked the departments of Health and Human Services and Agriculture for their evidence and followed up with written requests under the Freedom of Information Act.
When the federal government issued its latest dietary guidelines this year, the flossing recommendation had been removed, without notice. In a letter to the AP, the government acknowledged the effectiveness of flossing had never been researched, as required.
The AP looked at 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. The findings? The evidence for flossing is “weak, very unreliable,” of “very low” quality, and carries “a moderate to large potential for bias.”
Despite the new research, a Saskatoon dentist still thinks flossing every day is important.
“I can’t see myself telling patients to not floss after just one study,” said Bryce Bahrey, with Downtown Dental. “Even though this evidence has come out, I’m still going to be flossing my own teeth.”
Bahrey said he feels more studies need to come out saying that flossing doesn’t help before dentists will actually change their recommendations.
“I was a little shocked because as dentists we’ve never talked about it during conferences or seminars.”
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.
-With files from The Canadian Press.