The abscess on the root is commonly found in the following cases: 1.After the crown forms a cavity and bacterial infection occurs, the inflammatory secretion produced in the pulp penetrates the apical hole and accumulates under the periosteum to form an abscess, which can be drained by opening the pulp under local anesthesia, using the cavity in the crown to discharge the pus, and if necessary, cutting open the abscess, separating the pus cavity and placing drainage strips; 2.When the lesion bone and In case of chronic stimulation of calculus, the lesioned bone and granulation tissue should be removed from the root tip and periodontal pocket, and rubber drainage strips should be placed after thorough rinsing; 3. In case of gingival abscess accompanied by swelling in the vestibular sulcus and cheek, the abscess should be incised and iodoform gauze should be placed, and cephalosporin and nitroimidazole antibiotics should be applied systemically.