Plaque is a sticky film containing bacteria that covers your teeth, says the American Dental Association. After a meal or snack, the bacteria can release acids that attack tooth enamel. Multiple attacks to the enamel can break it down, triggering cavities.
With daily brushing and flossing, plaque can be removed. But lingering plaque can harden into tartar, making it more difficult to clean your teeth. Plaque buildup can swell your gums and cause them to bleed easily, which may be an early stage of gum disease.