Dental Health and Canker Sores

Canker sores are small, shallow ulcers that appear in the mouth and often make eating and talking uncomfortable. There are two types of canker sores:

  1. Simple canker sores. These may appear three or four times a year and last up to a week. They typically occur in people ages 10 to 20.
  2. Complex canker sores. These are less common and occur more often in people who have previously had them.

    Video Transcript

    American Dental Association:; American Academy of Oral Medicine:; iStock Photos; PhotoDune; AudioJungle

    Burning or tingling spot in your mouth? A canker sore may be on the way.They are not contagious, but you can have more than one at a time.Common causes are: Acidic foods. Spicy foods. Skin that's already irritated. Being on your menstrual cycle.Canker sores are really annoying but mostly heal on their own and don't leave a scar.Some over-the-counter medicines may sooth the area.If it's not better in 2 weeks, call your doctor.

What Causes Canker Sores?

The exact cause of most canker sores is unknown. Stress or tissue injury is thought to be the cause of simple canker sores. Certain foods -- including citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes, and strawberries) -- can trigger a canker sore or make the problem worse. Sometimes a sharp tooth surface or dental appliance, such as braces or ill-fitting dentures, might also trigger canker sores.

Some cases of complex canker sores are caused by an underlying health condition, such as an impaired immune system; nutritional problems, such as vitamin B-12, zinc, folic acid, or iron deficiency; or gastrointestinal tract disease, such as celiac disease or Crohn's disease.

Are Cold Sores and Canker Sores the Same Thing?

No. Although cold sores and canker sores are often confused with each other, they are not the same. Cold sores, also called fever blisters or herpes simplex type 1, are groups of painful, fluid-filled blisters. Unlike canker sores, cold sores are caused by a virus and are extremely contagious. Also, cold sores typically appear outside the mouth -- usually under the nose, around the lips, or under the chin -- while canker sores occur inside the mouth.

What Are the Symptoms of Canker Sores?

You may have a canker sore if you have:

  • A painful sore or sores inside your mouth -- on the tongue, on the soft palate (the back portion of the roof of your mouth), or inside your cheeks
  • A tingling or burning sensation before the sores appear
  • Sores in your mouth that are round, white or gray, with a red edge or border

In severe canker sore attacks, you may also experience:


How Are Canker Sores Treated?

Pain from a canker sore generally lessens in a few days, and the sores usually heal without treatment in about a week or two. Cankers sores treated with dental lasers exhibit almost complete relief of the symptoms immediately. Talk to your dentist about the procedure.

Can Canker Sores Be Prevented?

Although there is no cure for canker sores, and they often recur, you may be able to reduce their frequency by:

  1. Avoiding foods that irritate your mouth, including citrus fruits, acidic vegetables, and spicy foods
  2. Avoiding irritation from gum chewing
  3. Brushing with a soft-bristled brush after meals and flossing daily, which will keep your mouth free of foods that might trigger a sore

You should call your dentist about canker sores if you have:

  • Unusually large sores
  • Sores that are spreading
  • Sores that last 3 weeks or longer
  • Intolerable pain despite avoiding trigger foods and taking over-the-counter pain medication
  • Difficulty drinking enough fluids
  • A high fever with the appearance of the canker sores
WebMD Medical Reference Reviewed by Alfred D. Wyatt Jr., DMD on June 1, 2018



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