A bulge in the gums may be caused by apical periodontitis, gingival hyperplasia, gingival tumor, etc. 1. Periapical periodontitis: refers to the inflammatory disease that occurs in the tissues around the root tip, such as dental bone, periodontal membrane, alveolar bone, etc., may form a suppurative infection, which may lead to protruding gums, manifested as a localized abscess, which will gradually burst, with pus overflowing, and so may lead to a bulge in the gums. 2. Gingival hyperplasia: Gingival hyperplasia caused by chronic inflammation and other factors can also lead to a bulge in the gums. 3. Gingivoma: a growth on the gums, mainly from the periodontal membrane and gingival connective tissue, can also lead to a bulge in the gums. Gums have a bulge, there may be other reasons, need to go to the hospital to check the cause.