Periodontal disease includes periodontitis, but periodontal disease covers a much broader range than periodontitis. Periodontium is the supporting tissue of the teeth, which includes the gums, alveolar bone, and dental cementum, so the scope of periodontal disease is very broad, while periodontitis is just a branch of periodontal disease. Periodontitis is caused by tartar, soft plaque, or dental plaque around the teeth, which if not promptly removed by teeth cleaning, can lead to congested gums or bleeding during brushing. Severe cases can cause absorption of the alveolar bone. Once destructive absorption of the alveolar bone occurs, teeth will become loose and may even fall out. It can also be said that periodontitis is a severe stage in the further development of periodontal disease.