Editorial: Don’t toss that box of floss just yet

By The Herald Editorial Board

Don’t throw out that little box of dental floss just yet.

Or more likely, if you’re like your author, maybe you ought to dig it out of the bathroom cabinet and start using it more often.

An Associated Press report earlier this month that raised doubts about the effectiveness of flossing was almost certainly met with relief by those who are less than diligent about the dental hygiene chore.

Following a Freedom of Information request, AP reporter Jeff Donn, a Pulitzer finalist in 2012, looked at research focusing on 25 studies over the past decade. In comparisons between the combination of a using a toothbrush and flossing and use of a toothbrush alone, “the evidence for flossing was ‘weak, very unreliable,’ of ‘very low’ quality and carries ‘a moderate to large potential for bias,’” Donn reported.

Since 1979, the federal government, beginning with a surgeon general’s report and later as part of the Dietary Guidelines for Americans, has recommended flossing as part of necessary dental care.

But this year, following the AP’s request for the studies, when the government issued its latest dietary guidelines, the flossing recommendation had been removed without comment. In a letter to the AP, the government admitted that the effectiveness of flossing to prevent cavities or severe periodontal disease had not been adequately researched, as inclusion in the guidelines requires.

What happened after the AP story broke, however, was a bad case of truth decay.

In retelling the AP’s story on television and other media, details and context were often glossed over or left out. The result was a misrepresentation that flossing had been proved ineffective, when what the AP report showed was a lack of reliable studies on flossing’s effectiveness.

Snopes.com, the website known for debunking rumors and fact-checking conventional wisdom, pointed to that distinction, citing Dr. Scott Tomar, a public health dentist and oral epidemiologist at the University of Florida. Tomar agreed the evidence was weak:

“While that’s true … the absence of evidence is not at all equivalent to the evidence that something is ineffective.”

The reason that there are few good studies, Tomar and others have said, is the difficulties that arise in studying the practice. For a reliable study, a control group would have to be told not to floss at all for three to five years, and there would be few assurances that those who were flossing were doing it properly and regularly.

How truthful are you when your dental hygienist asks if you’re flossing every day?

One study left the flossing to professionals, the New York Times reported recently. A review of six trials found that when professionals flossed the teeth of children on school days for two years, there was a 40 percent reduction in the incidence of cavities.

Anecdotal evidence, however, may still provide the best guidance.

Snopes also cites Dr. Timothy Iafolla, a dentist and public health analyst for the National Institutes of Health: “As soon as a patient opens their mouth, he can tell which ones have been flossing and which ones haven’t been, because their gums are healthier.”

There’s also better evidence that flossing is effective in reducing the incidence of bleeding gums and inflammation, known as gingivitis, which can lead to periodontal disease, the progressive loss of bone.

As a dentist, Iafolla said, for his patients who start flossing, “the gums get healthier every time. Every dentist has that experience, I think.”

And even though Donn, the AP reporter, said in an interview with the Poynter Institute that he believes the best science indicates little benefit from it, he still uses dental floss.

“Yes, I still do,” he told Poynter, “to remove annoying bits of food stuck in my teeth. My wife yells at me when I use my finger or a fork.”