Periodontal disease is an infection of the tissues that support your teeth. It is generally divided into two subcategories: Gingivitis and Periodontitis. The longer plaque and tartar are on teeth, the more harmful they become. The bacteria cause inflammation of the gums that is called gingivitis. With gingivitis, the gums become red, swollen and can bleed easily. When gingivitis is not treated, it can advance to periodontitis. In periodontitis, gums pull away from the teeth and form "pockets" that are infected. The teeth may eventually become loose and have to be removed.