The main clinical manifestations of periodontitis are bleeding gums (bleeding from brushing or biting hard food, bloody morning saliva, or even spontaneous bleeding), elongated roots, larger gaps, loose and displaced teeth, weakness in chewing, and bad taste in the mouth, etc. The clinical manifestations are separation of gums from roots (loss of attachment and formation of periodontal pockets), root instability of teeth (reduction of alveolar bone height), and in severe cases, the teeth may become abscessed, painful, fall out or extraction. When gingival recession causes exposure of the root surface, the patient may show sensitivity to cold, hot, sweet, sour foods or mechanical stimuli.