Don't lie, everybody exaggerates how often they floss when they go to the dentist. However, maybe there’s no need to feel wracked with guilt the next time you skip a flossing session – there’s surprisingly little scientific evidence that flossing is good for your dental health.
Last year, the Associated Press (AP) sent Freedom of Information requests to the US departments of Health and Human Services and Agriculture asking for their evidence that flossing works. By law, these guidelines must be backed by scientific evidence.
They received a letter back from the authority that said they had never actually fully researched the benefits of flossing. This year's dietary guidelines from the federal government have been issued and it appears they have, without any notification or explanation, removed their recommendation that you should floss your teeth.
The concept behind flossing is that it helps remove plaque, a sticky film of bacteria, from in-between the teeth. This bacteria can cause tooth decay and gum disease. Most of this plaque is dealt with by brushing your teeth with fluoride toothpaste. There are areas, such as between your teeth, that brushing cannot reach. However, the extent to which flossing helps with this process of removing plaque has not been appropriately researched.
Two of the leading dental authorities in the US – the American Dental Association (ADA) and the American Academy of Periodontology – appear to base their flossing recommendations on outdated studies that tested a few very small sample groups for a short duration. One study tested just 25 participants after a single use of floss. Other research tended to focus only on milder “warning signs” such as bleeding, and did not look into gum disease or cavities.
The AP report also looked at 25 studies that evaluated the benefits of flossing and brushing compared to just brushing alone. The evidence in favor of flossing ranged from “weak, very unreliable" to “very low.”
The AP even suggested that corporations who produce flossing products have “paid for most studies and sometimes designed and conducted the research.”
Speaking about the studies that are used to justify flossing, Dr Marcelo W. B. Araujo, vice president of the ADA's Science Institute and former executive for Johnson & Johnson, told AP: "The funding can come from companies – no problem at all. The design [of the study] can start from the company."
Nevertheless, although the evidence is conflicting, many leading dentists still say that flossing is not totally pointless. ADA released a statement in response to the report, which maintained that “interdental cleaners such as floss are an essential part of taking care of your teeth and gums.”
Speaking to AP, National Institutes of Health dentist Tim Iafolla took the philosophy that flossing will not harm your teeth, however it might help then.
“It's low risk, low cost," he said. "We know there's a possibility that it works, so we feel comfortable telling people to go ahead and do it."