The incisor gap grows a bag without pain, there may be apical periodontitis, maxillary cyst, gingival tumor, gingival hyperplasia or polyps and other reasons. 1. Periapical periodontitis: the root site, alveolar bone, periodontal membrane and other tissues appear suppurative infection, may lead to the incisor gap grows a bag of fistula but does not hurt the phenomenon. 2. Maxillary cysts: cystic structures appear in the maxilla, which may also be manifested as a bag growing between the incisors without pain. 3. Gingival tumor: chronic inflammatory stimulation and other reasons, may lead to gum tumors, also manifested in the incisors grow a bag without pain. 4. Gingival hyperplasia polyps: do not pay attention to oral hygiene, plaque, calculus and other stimuli, may lead to gingival hyperplasia or polyps, can also lead to the incisor gap grow a bag without pain. The incisor gap grows a bag without pain, there may be other reasons, need to go to the hospital in time to check, clear cause.