Flossing reduces the number of bacteria in your mouth. There are millions of these microscopic creatures feeding on food particles left on your teeth. These bacteria live in plaque which can be removed by flossing. Brushing your teeth gets rid of some of the bacteria in your mouth. Flossing gets rid of the bacteria the toothbrush can’t get to. That’s the bacteria hiding in the tiny spaces between your teeth. If you do not floss, you allow plaque to remain between your teeth. Eventually it hardens into tartar. Plaque can be removed by brushing. Only the dentist can remove tartar.