Canker sore on mouth
A canker sore is a painful shallow ulcer inside the mouth; gentle care helps, but a persistent or unusual sore needs examination.
The short answer
A canker sore is a small, shallow ulcer on the non-keratinized lining inside the mouth, often with a pale center and a red border, and it is not the same as a cold sore. It can make eating, brushing, or speaking uncomfortable.
What is the direct answer?
What does this question mean?
Canker sores commonly affect the inner lip, cheek, soft palate, or tongue. Local trauma, stress, illness, nutritional problems, hormonal changes, or an immune-related condition may be associated with them, but one sore may have no clear trigger.
What can you do next?
Use a soft brush, choose cool soft foods, and avoid spicy, acidic, or rough foods that touch the ulcer. A dentist can recommend a protective or anti-inflammatory mouth treatment after checking the lesion and your medical history.
When should you seek dental care?
Arrange an examination if the ulcer is unusually large, very painful, recurrent, accompanied by fever or several other sores, or does not heal as expected. Urgent care is needed if mouth pain or swelling interferes with drinking or breathing.
What should you ask the dentist?
Ask whether the sore has the typical location and appearance of a canker sore or whether trauma, infection, medication, or another condition is more likely. Ask which topical treatment can protect it and whether recurrent episodes need further evaluation.
Frequently asked questions
Are canker sores contagious?
Typical aphthous ulcers are not spread like cold sores, but an examination is useful when the appearance is unusual.
Can toothpaste irritate a canker sore?
Some ingredients or strong flavors may aggravate sensitive tissue, so use a mild product and avoid scrubbing the ulcer.