Canker sores (aphthous ulcers or recurrent aphthous stomatitis) are painful mouth ulcer(s) that usually appear after a gradual burning or tingling sensation. Canker sores are usually found on the movable, non-keratinized (less protected) tissues in the mouth, including the inner surface of the lips, the cheeks, under the tongue, and back of the throat. You may remember the first time you experienced a canker sore and looked in your mouth to find a small (2-4 millimeter) white or yellow ulcer with a red halo around it. Canker sores usually occur in clusters of less than six, and tend to recur periodically in response to stress, during the menstrual cycle and hormonal changes, and from food allergies and dietary deficiencies (especially iron and vitamin B12). Canker sores can occasionally mimic other dental problems. Patients will sometimes come to my office thinking that they have an infected tooth or an abscess on their gum, and are surprised to discover that the cause is a canker sore. Canker sores usually cause pain for about four or five days, and generally completely resolve in 10-14 days. The cause of canker sores is unknown, but some researchers have speculated that there may be an inherited predisposition or defect in the immune system responsible for them.

Small as these ulcers are, they seem to transmit a disproportionately large amount of pain. Treatment for canker sores is primarily centered on relieving the pain associated with them. Your dentist can prescribe a viscous 2% lidocaine rinse to be swished around the mouth every 3 hours to "numb" the canker sores and provide relief. The over-the-counter product Orabase, which contains a protective barrier called carboxymethylcellulose, can be very effective in managing canker sores. In addition, your dentist can have the pharmacist add the mild steroid triamcinolone at 0.1% to the Orabase to improve its effectiveness. Canker sores can also be treated with chemical or physical cautery (searing of tissue). Chemical cautery can be accomplished with phenol containing compounds and silver nitrate sticks, and physical cautery may be preformed with soft-tissue dental lasers or other heat-generating devices.

In some cases, canker sores can occur in high numbers and cause severe and debilitating pain. In these cases, your dentist may consider prescribing an oral suspension of the drug tetracycline at 250 mg to be used four times a day for ten days. The drug is to be held in the mouth for two to five minutes and then swallowed. Tetracycline should not be used for children under ten because it can discolor developing teeth. For more serious cases of canker sores, the dentist can prescribe corticosteroids. A good choice is the drug dexamethasone, which is used topically as a solution that is rinsed and spit out twice a day for five days. A different corticosteroid called prednisone can be taken orally, in tablet form, starting at 40 milligrams per day and then tapered for 10 days. Severe pain can also be effectively managed by a combination of benadryl, maalox and dyclone, sometimes called "magic mouthwash".

The decision of how canker sores should be treated is up to you and your dentist. Many times, no treatment is needed. In more severe cases, however, it should be comforting to know that your dentist has a wide arsenal of remedies available to do battle with those pesky canker sores.