Gum disease is usually caused by a build-up of plaque, an invisible sticky layer of germs that forms naturally on the teeth and gums. Plaque contains bacteria, which produce toxins that irritate and damage the gum. With time, plaque hardens into a substance called tartar that can only removed by a dentist. You can get gum disease if you don't clean your teeth well, smoke or chew tobacco, have infections such as, diabetes, AIDS or leukemia, high level of stress and poor diet.
Attribution: Straight Talk Foundation