Recently, the Associated Press decided to run with its story about the lack of evidence for the effectiveness of dental floss. It’s unclear why the AP suddenly decided to run this piece–none of the evidence it cites is new. Most of it dates from before 2010. Last year, some tabloids ran with this story, which may have been the precipitating event. Or maybe it’s just because we’ve become aware of how unpopular flossing is, so it seemed like the timing was right for a hit-piece on an unpopular bastion of orthodoxy: the dentist who tells you to floss.

The truth is that, yes, science has not yet thoroughly proven that flossing works. But if you ask any dentist, they will tell you that flossing works. They can tell the difference between patients that floss and those that don’t, and it’s significant. So why can’t science prove it? There are several possible reasons.

woman flossing

People Don’t Floss Correctly

One of the possible confounders in the effectiveness of flossing is that people aren’t doing it properly. It’s not easy to properly floss your teeth to remove all the plaque from between your teeth. Most people just want to get the chore over with quickly, so they never take the time to learn or perform their flossing properly.

A dramatic illustration of this comes from one of the studies cited by the AP piece. This systematic review looked at studies of three different approaches to flossing teeth. When young adolescents were asked to floss their own teeth for two years, there was no evidence of benefit. But when younger children were given professional flossing every school day for 1.7 years, they experienced a 40% reduction in their risk of cavities between teeth. This seems like pretty strong evidence that flossing works–if you do it right.

This might be part of the reason why interdental brushes do better in clinical studies–they’re easier to use properly than dental floss, so people actually accrue the benefits they’re supposed to get.

People Lie about Flossing

Another possible reason why we can’t track the effectiveness of flossing is that many people lie about flossing. Studies have shown that 27% of people admit to lying to their dentist about flossing, and the actual numbers may be much higher. So it’s quite possible that a significant percentage of people participating in studies are lying as well. As we said, flossing is not very popular. It wouldn’t take a very large percentage of people lying in studies to obscure the benefits of flossing.

Our Studies Aren’t Designed Properly

Another reason why flossing studies might not show results is that they’re just not designed properly. Most of the benefits of flossing are related to gum disease. Gum disease risk is also strongly mediated by genetic factors, which aren’t screened for or controlled for in flossing studies.

The studies may also not have a large enough population or long enough follow-up. Of course, if you make the studies larger and longer, it’s more likely that you end up with more interference from the other two factors.

In all these respects, they might be victims of complacency. Everyone has taken it for granted for over 100 years that flossing works. Studies that are large and long and thorough are expensive–why would anyone pay for such studies if the outcome will only confirm conventional wisdom.

From that standpoint, flossing might benefit from a sea change that is now calling it into question. In response, we may design new and larger studies that actually prove the benefit of flossing.

Do Your Own Study

If you’re still not convinced that flossing works, go ahead and perform your own flossing study. If you’re not currently flossing, spend six months flossing every day and see what a difference it makes.

If you are currently flossing, go ahead and stop for six months. You’ll probably experience:

  • Bad breath
  • Red, inflamed gums
  • Bleeding gums
  • More food sticking around teeth
  • Greater tartar buildup — you’ll notice this during your hygiene visit if not before

Once you start to experience these negative effects, please resume flossing, hopefully assured that the practice is actually helping your oral health.

Or you can switch to an interdental brush and see if that works better for you.

If you are looking for a dentist in the Orlando area that can help you maintain your oral health, please call (407) 834-6446 today for an appointment with Dr. Michael L. Weinstock in Altamonte Springs.