A: Canker sores are small, shallow ulcers that appear in the mouth. They are typically white or yellow and surrounded by a bright red area and usually appear on the inner surface of the cheeks, lips, tongue, soft palate and the base of the gums. They do not appear on the outer lip and should not be confused with cold 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, tomatoes or strawberries) — can trigger a canker sore or worsen it. Another cause may be lack of certain vitamins and minerals in the diet (especially iron, folic acid or vitamin B-12).
Canker sores often make eating and talking uncomfortable. Pain generally lessens in a few days and the sores usually heal without treatment in about a week or two. Medication is not necessary; however if it is very large or last more than three weeks, contact your dentist. You may need an antimicrobial mouth rinse or a corticosteroid ointment to help ease the discomfort.
There are over-the-counter medications that help, which should be applied directly to the sore. Avoid hot and spicy foods as well. If they persist or frequently return, you should see your dentist to determine if there is another cause of the mouth ulcers.
Information provided by Dr. Rob Swanson, Swanson Dental, 2423 Willis Ave., Perry, (515) 465-5170.