<s>[INST] Hi my sister was at the dentist recently who noticed a spot near an area where she has lost some bridge work. She is on medication and her teeth are in poor condition. The dentist said the spot could be caused by a number of factors - there is a white substance under the spot [/INST] Hi Dear, Understanding your concern about your sister. Gum soreness could be because of number of reasons like gingivitis means gums inflammation, periodontitis, autoimmune diseases, vitamin deficiency, menstrual factors or because of mouth injury. Appliances like bridges could cause irritation to that area and constant irritation can cause ulceration will lead to spot and white patchy area. Treatment for this is saline rinses, gargles with mouth wash. Dologel or pain relieving mouth paints the best treatment options. Mix equal parts of water and HY Chat Doctor.  Repeat it 3 times a day. Milk of magnesia application is another treatment option. Get well soon. Best wishes, </s>