Q: Should you floss before or after brushing your teeth?
A: It’s debatable. On the one hand, if you floss first, brushing after will help sweep away whatever plaque and debris the floss has loosened between your teeth but has not removed from your mouth. In addition, the fluoride from the toothpaste may better penetrate between teeth where the plaque has been removed and stay on the teeth longer. On the other hand, some dentists say that if you floss first, you might push the loosened plaque and debris into the gum margin when you brush.
According to the Canadian Dental Association, brushing after flossing is more effective for preventing tooth decay and gum disease, but the American Dental Association says either way is fine.
Do whatever works best for you. In fact, there is no rule that you even need to floss and brush at the same time, though that’s more convenient for most people. What’s most important, experts agree, is to floss at least once a day and brush at least twice a day—and to use the right technique.