The 8-year-old child sleeps up and finds that the back of the bed of the teeth is swollen may be caused by periodontal abscess or periapical abscess, need to see a doctor for periodontal treatment and root canal treatment. 1. Periodontal abscess: If dental caries or tooth eruption and oral hygiene is poor, it will cause food impaction and lead to periodontal tissue infection and inflammation; and then the emergence of gingival abscess and pain and other symptoms, due to the relative activity of bacteria at night and aggravate the condition leading to the emergence of morning tooth swelling and other symptoms. 2. Periapical abscess: dental caries caused by pulpitis if not treated in time, the spread of inflammation will cause periapical periodontal tissue infection and inflammation; will lead to the apical periodontal tissue pus or fistula and other symptoms, at the same time, the night symptoms will be exacerbated, resulting in swelling and pain in the bed of the teeth in the morning. The 8-year-old child sleeps up to find the back of the bed of the teeth swollen may also be related to other reasons, it is recommended to consult a doctor in a timely manner to clarify the diagnosis of targeted treatment, to avoid delaying the condition.