The later stage of gum disease in which unremoved plaque hardens into calculus (tartar). With periodontitis, as plaque and calculus continue to build up, the gums begin to recede (pull away) from the teeth, and pockets form between the teeth and gums. With advanced periodontitis, the gums recede farther, destroying more gum tissue and progressing to the bone. At this late stage of gum disease, teeth (even healthy teeth) can become loose, fall out, or have to be extracted by a dentist.
Inflammation of the tissues investing and supporting the teeth, including the cementum, peridontal ligament, alveolar bone, and gingiva.