Endodontitis without root canal treatment may develop into acute apical periodontitis, chronic apical periodontitis, etc., as follows. 1. Acute apical periodontitis: the apical periodontium appears plasma inflammation, and then develops into purulent inflammation, the scope of the lesion is from small to large, the alveolar bone can be limited osteomyelitis, and in severe cases, it can be osteomyelitis of the jawbone. 2. Chronic periapical inflammation: manifested as inflammatory granulation tissue formation and destruction of alveolar bone, with the development of the disease, periapical granuloma can develop into chronic periapical abscess or periapical cyst. Endodontitis without root canal treatment may also develop into other diseases, it is recommended to go to the hospital in time to receive early formal treatment.