For years, dentists have told us to floss as well as brush our teeth. And it seems to make sense: less gunk between our teeth should lead to less decay. Yet surprisingly, there’s little evidence it’s true, as it’s never been put to the test in a large clinical trial.

Some small studies have found that flossing helps combat gum disease, but there’s no compelling evidence that it also stops tooth decay. So does that mean it’s pointless? Not at all. First, gum disease is a major cause of tooth loss.

Read more at Science Focus.