A hole in the gums may be caused by chronic apical fistula, rupture hole of periodontal abscess and so on. 1. Chronic apical fistula: If the apical periodontitis is not treated in time, the infection continues to develop and spread nowhere, long-term stimulation will involve the bone, resulting in the destruction of the alveolar bone, the formation of fistula. At this time should be timely root canal treatment or surgical treatment in order to get the root cause. 2. Periodontal abscess rupture hole: periodontal abscess is developed from periodontitis, in the periodontal tissues caused by limited suppurative inflammation, the formation of abscess, may involve the alveolar bone, the gingival surface can be seen in the formation of sinus tracts, extrusion can be seen in a small amount of pus oozing. An abscess incision and drainage is usually required. Gums have a hole may also exist other causes, it is recommended to go to the dental specialist, a clear diagnosis, under the guidance of the doctor for treatment.