It's a familiar scene in a dentist's office: he or she asks if you've been flossing regularly.
Of course you say "yes"...whether it's the truth or not.
But according to a new report by the Associated Press, what is true is a revelation that might shock you to your gums: the case for flossing is "weak, very unreliable."
"It all came about when my son was visiting an orthodontist," says investigative reporter Jeff Donn, "and he said, 'I have a real investigative story: there's really no proof that flossing works.'"
Despite his initial skepticism, Donn discovered that the orthodontist was right. Out of 25 studies he reviewed on the subject, nearly all said that the benefits of regular flossing were minimal.
"Research as recent as last year can't demonstrate that it actually works," he says.
Flossing was first recommended by the American Dental Association in the early part of the 20th century.
"They based that recommendation in 1908 simply on what dentists said they were doing," says Donn.
Many studies since that time claimed floss is effective, but they were conducted by companies that made floss.
"That doesn't mean, per se, that they're bad studies but it does raise questions of bias," he says.
One recent study suggested some evidence that flossing may help with gum inflammation, but that the benefits might not be enough for the user to notice a change.
Donn says that continuing to floss isn't necessarily detrimental – and it can really help to get at some nasty food stuck in your mouth – but dentists do say most people are flossing the wrong way.
"Slide the floss in between the teeth," he says, "and up the sides of the tooth, in effect, not like sawing a motion."