Swollen gums may be caused by trauma, or inflammation such as dental disease, periodontal disease, oral mucosal disease, which need to be determined in the hospital based on medical history and oral examination. 1. Trauma: when the impact of external forces or foreign body damage, may cause internal hematoma of the gums, manifested as localized redness, swelling and pain. 2. Inflammation: when the teeth apical periodontitis, inflammation can reach from the periosteum to the submucosa, causing localized swelling of the gums, periodontal disease due to tartar and other external stimuli, can also cause inflammation of the gums, localized swelling under the action of inflammation, oral mucosal diseases herpes, candidiasis, ulcers and other diseases can cause swelling of the gums. Gum swelling, it is recommended to go to the hospital in time to check the cause of timely treatment, to avoid affecting oral health.