Pus on the teeth, referring to the gums should be long pus, belongs to the suppurative inflammatory problem, and periodontitis, wisdom teeth pericoronitis and periapical lesions and other factors. 1. Periodontitis: If the patient has more serious periodontitis, there will be a large number of bacterial reproduction in the periodontal pockets, and the metabolites produced, which can’t be discharged in time, will form abscesses in the gums, which in turn will cause periodontal abscesses. 2. Wisdom tooth pericoronitis: mainly wisdom teeth in the process of eruption is not smooth, impeded, not not fully erupted, the connection between the eruption part and the end of the eruption part, easy to residual food debris and other substances, which may lead to bacterial reproduction, chronic inflammation, over time, it will be easy to form a pericoronary abscess. 3. Periapical lesions: mostly caused by necrosis of the nerve, not given timely treatment, resulting in infection, when the patient has an acute attack, there will be symptoms of periapical abscess. It is recommended to go to the stomatology department of the hospital, determine the specific cause of the disease with the help of the doctor, and then carry out the corresponding treatment.