There is no direct clinical data on how long it takes for a gum ulcer to become cancerous. Usually, gum ulcers are almost never cancerous after active treatment. Gum ulcers, also called ulcerative gum lesions, are mostly triggered by traumatic factors, genetic factors, mental factors and dietary factors, and may also be caused by some immune system diseases, such as AIDS, syphilis and diabetes. However, if ulcers occur in the gums, papillary or nodular lumps, painful, loose or lost teeth, facial enlargement, difficulty in chewing and opening mouth with local bleeding and foul odor, it is necessary to pay attention to the possibility of precancerous lesions, and it is recommended to consult the oral mucosa department immediately for clear diagnosis. In daily life, patients should actively remove local irritants in the mouth to prevent ulcer formation, such as residual crowns, residual roots, bad restorations, bad orthodontics, etc. Eat a reasonable diet that is light and rich in calories, high protein, vitamins and trace elements. It is recommended to eat more fresh vegetables and fruits and not to eat spicy and stimulating and overly hot and hard foods. At the same time, maintain dental hygiene, avoid damage to the oral mucosa, maintain a good mood, avoid angry and irritable behavior. And once every six months, you should have a checkup at the stomatology department.