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Here’s How You Wasted 730 Minutes Last Year

3 minute read

If you followed dentists’ orders, you spent about 730 minutes last year—or more than half a day!—shoving waxed string between your teeth. But a growing body of evidence suggests all the flossing is a waste of time.

A TIME article last year drew attention to a 2008 review of the existing research on flossing, which found the standard advice to floss in order to prevent cavities and gum disease was “not supported by scientific evidence.” Another review from 2011 concluded that flossing may modestly reduce your risk for inflammation of the gums (gingivitis), but doesn’t fight plaque, which causes cavities. And now, in a letter to the Associated Press, the government acknowledged that the effectiveness of flossing has not been properly researched.

So, do you really need to keep flossing? As TIME wrote last year:

“The benefit from flossing is minimal and research shows it does not have a major impact on tooth cleaning,” said Dr. Damien Walmsley, a professor of dentistry at the University of Birmingham (UK) and a scientific advisor to the British Dental Association. He added that if you’re brushing properly, flossing is a “non-essential extra.”

There’s a practical problem with floss, one that Dr. Marcelo Araujo, vice president of the ADA’s Science Institute, concedes and many recent research efforts underscore: very few people do it properly. Snap the floss straight down into your gums, and you can irritate them. “Any time you’re causing trauma to your gums, they tend to recede,” Araujo explains. That recession can lead to sensitivity and other issues such as decay.

There’s a lack of evidence that it does good. Unlike a trained dentist, “in the hands of a regular user” there’s not much evidence that regular flossing does any good, says Dr. G.A. van der Weijden, co-author of the 2008 review and a professor of periodontics at the University of Amsterdam.

Even between-the-teeth brushes can irritate the gums. If these floss warnings seem like an endorsement for those little between-the-teeth brushes, Araujo says those too can irritate your gums—especially if you have narrow spaces between your teeth. “It’s all about each individual’s mouth, so we recommend talking with your dentist about which interdental cleaning method is best for you,” he says. He also recommends selecting products featuring the ADA’s seal of acceptance, which ensures your floss—or interdental brush, or water flosser—is safe and performs as advertised.

Both Walmsley and Araujo agree thorough brushing is your most effective weapon against dental debacles. Despite the lack of hard evidence, some form of between-your-teeth cleaning may also be helpful, especially if you have largish gaps that tend to grab and hold food debris. (If you usually dislodge chunks of food when you floss, then it’s pretty clear you’re benefitting from the practice, Walmsley says.)

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Write to Kate Samuelson at kate.samuelson@time.com