If the root tip abscess is not treated in time, it may lead to the emergence of sinus fistula in the skin or mucous membrane, loosening and falling off of the affected tooth, osteomyelitis of the jaw bone, etc. The details are as follows. 1. Skin or mucous membrane sinus fistula: apical pus can be discharged through the mucous membrane or skin, broken in the mucous membrane or skin surface of the pus discharge holes for a long time will form sinus tracts, fistulas, such as gingival fistula, gingival sinus, buccal sinus, facial sinus and so on. 2. Loose teeth: pus can be discharged through the periodontal membrane from the gingival sulcus or periodontal pockets, forming periodontal sinus tracts, causing serious damage to the periodontal membrane fibers, leading to loosening of the affected teeth, or even fall off. 3. Jaw bone osteomyelitis: it occurs on the basis of acute purulent periapical inflammation and periapical abscess, the inflammation spreads outward from the bone marrow cavity, which can involve the bone matrix and periosteum and cause bone destruction. There may be other effects of untreated apical abscess, so it is recommended to go to the hospital in time to receive professional treatment as soon as possible.