Gum disease begins when plaque adheres at and below the visible edge of your gums. If plaque is not removed every day by brushing and flossing, it hardens into tartar (also called calculus). Tartar promotes a bacterial infection at the point of attachment. In these early stages, gum disease is called gingivitis.
Your gums may be a bit red, but you may not notice anything. As gingivitis gets more serious, tiny pockets of infection form. Your gums may be puffy and may bleed a little when you brush, but it is not painful. Over time, the infection destroys the gum tissue. Eventually, you may be at risk of losing one or more teeth.