According to the Centers for Disease Control and Prevention, nearly half of American adults aged 30 and older have some form of gum disease, also known as periodontal disease. This oral health condition is an infection of the soft tissues that support the teeth and is caused by plaque. Plaque is the sticky film of bacteria that forms on teeth, and when it is left there for too long, it hardens and turns into tartar. It’s tartar that irritates the gums and causes inflammation. If you notice that you have red or swollen gums, bleeding gums after brushing, or sensitive teeth, you might be in the beginning stages of gum disease.