When severe periodontitis is accompanied by loose teeth, it is difficult to keep the teeth and timely treatment is recommended. 1. Periodontitis is a chronic infectious disease that can be categorized into three types: mild, moderate and severe. Severe periodontitis usually has more obvious periodontal abscess or inflammation of the gums, large loss of connective tissue attachment, alveolar bone resorption of more than 1/2 of the overall length of the teeth, tooth loosening symptoms, so basically it is difficult to keep teeth. 2. And severe periodontitis can also appear teeth displacement, food impaction, root exposure, retrograde pulpitis and other complications, if the teeth are not extracted, it is difficult to completely cure periodontitis. Suffering from periodontitis is recommended to be treated as early as possible, the earlier the treatment, the more conducive to the preservation of teeth, and the need for regular review to maintain oral hygiene.