Canker sores caused by
Canker sores are shallow ulcers in the soft mouth lining, often triggered by local injury, stress, or immune sensitivity rather than infection.
The short answer
A canker sore is a shallow ulcer of the non-keratinized mouth lining, commonly triggered by minor trauma, stress, or immune sensitivity.
Where do canker sores usually develop inside the mouth?
Canker sores, also called aphthous ulcers, usually affect the inside of the lips or cheeks, the tongue, or the soft palate. They are different from cold sores, which are caused by herpes simplex virus and usually occur on the outer lip.
What can you do to ease a canker sore while it heals?
Rinse gently with salt water, choose cool soft foods, avoid spicy or acidic foods, and use a soft toothbrush. A pharmacist or dentist can advise on a topical corticosteroid or protective oral gel when appropriate.
When does a canker sore need dental assessment?
Arrange an examination if an ulcer lasts beyond two weeks, repeatedly returns, is unusually large, or makes eating and drinking difficult. Urgent assessment is needed for trouble swallowing, dehydration, or swelling of the face or throat.
What should you ask about repeated mouth ulcers?
Ask whether the ulcer looks aphthous or traumatic, whether a sharp tooth or appliance is rubbing it, and whether recurrent ulcers warrant checking medicines, nutrition, or another oral condition.
Frequently asked questions
What is the main point about canker sores caused by?
A canker sore is a shallow ulcer of the non-keratinized mouth lining, commonly triggered by minor trauma, stress, or immune sensitivity.
Ask whether the ulcer looks aphthous or traumatic, whether a sharp tooth or appliance is rubbing it, and whether recurrent ulcers warrant checking medicines, nutrition, or another oral condition.?
Ask whether the ulcer looks aphthous or traumatic, whether a sharp tooth or appliance is rubbing it, and whether recurrent ulcers warrant checking medicines, nutrition, or another oral condition.
Who wrote this page
This library is published by Dental Nation, a licensed dental group practising in the United Arab Emirates. Pages are written and overseen by the same clinical team that treats patients in our clinics, and are held to a fixed editorial standard for safety and accuracy.
This page is patient education, not medical advice, and cannot replace an examination. Anything urgent — facial swelling, trauma, uncontrolled bleeding or severe pain — needs a dentist or emergency care now.