Some say the health benefits of dental floss are unproven. Not so fast, experts say.


Don’t toss your dental floss just yet.

Yes, a recommendation for daily flossing was removed from the U.S. Dietary Guidelines earlier this year, after it was found that the health benefits of regular flossing had never been proven.

Yes, further analysis into 25 studies comparing tooth-brushing alone with tooth-brushing and flossing found “weak, very unreliable” evidence that flossing is actually good for us, with a “moderate to large potential for bias,” according to the Associated Press, which specifically asked the Departments of Health and Human Services and Agriculture for the evidence.

Despite this news, however, dentists are standing by their advice. We asked Matthew Messina, a consumer advisor for the American Dental Association and dentist in private practice in Cleveland, Ohio, for his take on the adjusted guidelines and the media frenzy that’s followed. Here’s what he had to say.

There aren’t good studies because there hasn’t been a need

“There’s not a tremendous amount of long-term evidence, pro or con, on flossing,” says Messina. “I think that comes out of the fact that the recommendation was put into place years ago—before there was a lot of scientific basis for these things—and no one’s gone back to catch up on the research.”

In the United States, oral health is in a good place, he adds, with people living longer and keeping their natural teeth well into old age. “I’d rather the medical community invests in researching cancer and other really useful things,” he says, “as opposed to spending a tremendous amount of time and money on studies about dental floss.”

Flossing removes food (and bacteria) that brushing can’t

With more than 500 species of bacteria in the mouth, Messina says, preventing gum disease and tooth decay is all about reducing as much of the bad bacteria as possible. “It’s a numbers game,” he says. “If we can take away the food sources that are causing some of that bacteria, that’s a good thing that will lead to a healthier environment.”

Brushing can do a great job of removing bacteria from the teeth itself, he says, but even if you do the world’s best job at brushing, chances are you’ll still see food particles when you floss afterward. “Anyone who practices dentistry knows that flossing makes a difference,” he says, “and they can show you case after case of people who are great examples of that.”

Flossing has been shown to reduce inflammation

“The body’s response to all these bacteria in your mouth is inflammation; it’s a defense mechanism to wall things off that could be harmful,” says Messina. “So if we have a process that removes some of these bacteria and reduces inflammation—and we know that inflammation is bad for your general health—then it’s a step in the right direction.”

Messina hopes that ongoing research on inflammation, a contributor to many types of chronic disease, will help strengthen the link between good oral hygiene (including flossing) and overall health. It’s worth noting that one 2012 study did find that flossing reduced inflammation throughout the body—but it did not, as commonly believed, seem to offer any protection against heart disease.

The cost is low, and the potential benefits are high

Dental floss is inexpensive and easy to find at any drug store. And while flossing itself may not be the most fun experience, it only takes a few minutes and—for most people—is relatively painless. (If you really hate it, single-use plastic dental-floss picks may make the practice less unpleasant.)

And, okay, skipping a day or two isn’t the end of the world. “As a dentist, I can tell you that flossing every day, once a day is the best thing,” says Messina. “But I’ll take three days a week, I’ll take sunny days or rainy days, I’ll take some combination of more than just the night before you come in to the dentist. Sometimes is better than never as a step toward getting those benefits.”