Medical benefits of dental floss unproven

Dentists provide samples to their patients; the American Dental Association insists on its website that, "Flossing is an essential part of taking care of your teeth and gums." Last year, the Associated Press asked the departments of Health and Human Services and Agriculture for their evidence, and followed up with written requests under the Freedom of Information Act. When the federal government issued its latest dietary guidelines this year, the flossing recommendation had been removed, without notice. The two leading professional groups — the American Dental Association and the American Academy of Periodontology, for specialists in gum disease and implants — cited other studies as proof of their claims that flossing prevents buildup of gunk known as plaque, early gum inflammation called gingivitis, and tooth decay. [...] research, like the reviewed studies, focused on warning signs like bleeding and inflammation, barely dealing with gum disease or cavities. In an interview at his private practice in New Jersey, he said that the impact of floss might be clearer if researchers focused on patients at the highest risk of gum disease, such as diabetics and smokers. When the ADA was asked for proof of its claim that flossing helps prevent early gum disease and cavities, the group cited the 2011 review and a 2008 two-week study that measured bacteria and did not even consider gum disease. Even companies with a big market share of the flossing business — by next year, the global market is predicted to reach almost $2 billion, with half in the United States, according to publisher MarketSizeInfo.com — struggled to provide convincing evidence of their claims that floss reduces plaque or gingivitis. Procter & Gamble, which claims that its floss fights plaque and gingivitis, pointed to a two-week study, which was discounted as irrelevant in the 2011 research review. Though frequency is unclear, floss can dislodge bad bacteria that invade the bloodstream and cause dangerous infections, especially in people with weak immunity, according to the medical literature.