Canker Sores

Although the exact cause of this type of mouth ulcer is unknown, hereditary factors, stress or tissue injury are the likely causes of canker sores on the gum, tongue or soft palate. Acidic or citrus foods can also trigger a canker sore, as can sharp teeth, braces or ill-fitting dentures. Cigarette smoking and allergies may also increase the likelihood of canker sores. Some cases of canker sores might highlight an underlying health condition, including nutritional and immune system problems, and gastrointestinal tract disease.