The dental world was left reeling last week after the federal government declared flossing – touted for decades as a bedrock of oral health care – isn’t scientifically proven to fight plaque.
The news came to light after the Associated Press invoked the Freedom of Information Act to demand scientific evidence of flossing’s benefits. Government officials revealed that 25 studies on flossing produced “weak” and “unreliable” results. Although since 1979, flossing has been recommended under the U.S. Dietary Guidelines for Americans, it’s now off the list. Not so for the American Dental Association, and the American Academy of Periodontology, which continue to recommend flossing.Most dentists still swear by it, like Andrew Sullivan, chair of the Rutgers School of Dental Medicine’s Department of Periodontics. Sullivan treats many patients who suffer from periodontitis, an advanced form of gum disease that deteriorates bone, resulting in pain and tooth loss. He explained to Rutgers Today why tossing the floss is a bad idea.
Why should Americans keep flossing, even if the government no longer recommends it?
Sullivan: I’ve been a dentist 48 years, and for 48 years I’ve been telling patients to floss. Flossing helps with caries, or dental cavities, which often occur between teeth. It does remove plaque, which is the cause of gingivitis and periodontal disease. Brushing does not clean in between the teeth so flossing, or some use of interdental device – a little brush, or water pick – is necessary to clean those areas that the brush misses. Water picks can be helpful in flushing away debris, but it’s questionable as to whether they remove plaque.
What effect has flossing, or not flossing, had on your patients?
Sullivan: The typical patients who come in with periodontal disease have bad oral hygiene; their brushing and flossing are not what we feel they should be. Usually, when they’re put on appropriate oral hygiene procedures, including flossing, it reduces the clinical signs and symptoms. We see reduced inflammation, reduced bleeding of the gums.
Why has it been hard to prove that flossing works?
Sullivan: One reason might be because it’s difficult to design studies where you’d get approval to have, say, 100 people who are flossing and 100 who aren’t. It might be dangerous for the half that isn’t flossing.
You’re not going to do a study that puts people at risk by asking them not to floss for a long time. In 1965, there was a study that showed plaque leads to gingivitis. Before that, we couldn’t prove it but that study, which was done on dental students, had them go for days without brushing their teeth. There wasn’t significant harm from that. It was reversible. Once they started brushing their teeth again, the gingivitis went away.
Why do so many people hate to floss?
Sullivan: I think people don’t floss because it’s difficult. It’s time consuming, and often because they’ve never been taught how to do it. It can be hard to do correctly. A common mistake is just snapping the floss between your teeth. You have to wrap it around the surface. You can lacerate your gum if you snap it too hard, but I’ve never seen a flossing injury that did permanent damage.
What are you going to tell patients now if they say they’re not going to floss because they heard it doesn’t do any good?
Sullivan: I am afraid the public will dismiss flossing. For some, dropping it from the guidelines will make a difference. I’m going to tell my patients that based on many decades of experience, flossing is valuable, it contributes to oral health and I’m going to continue to recommend it. Maybe the good that will come from this is that there will be an impetus for researchers to come up with innovative protocols that will answer questions with enough scientific rigor to prove that flossing works.
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