Canker Sores - Causes, treatment and remedies

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By Dr. David Leader

Before leading the young man into my treatment room, I ask his mother if she has any questions. She says that there is a serious problem plaguing her son. He gets canker sores in his mouth. The sores make it difficult for him to eat and drink certain foods. When he has a canker sore, he cannot brush his teeth. He wants to know the best way to get rid of canker sores. Why does he get these sores? What can we do when he gets a sore? Is there a way to prevent mouth sores? What's the best way to get rid of canker sores?

The young man is eager to discuss the problem. He points to a spot inside his lower lip, a red ulceration with a white rim. The entire sore is only about an eighth of an inch across. He has no other medical problems. He takes no medication, nor does he have a fever. He confides that he gets sores like this one after another. Sometimes, he has two or more at a time. He thinks that he gets more of them when he is nervous about school and dating. The individual cankers usually last for a week or two.

Dentists refer to canker sores as aphthous ulcers or aphthae. Dentists are able to tell aphthae from similar appearing disorders such as oral herpes. Aphthae or apthous ulcers always appear on the smooth lining of the mouth, inside the lips and under and on the tongue. Oral herpes sores are similar, but affect different areas of the mouth and lips.

Some people are prone to canker sores. Aphthae may appear without provocation or cause. Then again, an abrasion from a sharp piece of food, pressure on the lips from playing an instrument or sleeping face down, and emotional stress may cause an outbreak of ulcers. Another cause is a common chemical, sodium lauryl sulphate (SLS).

People who are prone to aphthous ulcers learn which foods they must avoid. Many find that acidic food and drink such as orange, pineapple, and tomato cause, and irritate mouth ulcers. Others may find that eating crunchy foods with sharp edges like potato chips and hard cereals bring out the worst canker sores.

Sodium lauryl sulphate or SLS is a foaming agent. Most toothpastes and shampoos include SLS as a major ingredient. SLS is drying and irritating. Toothpastes for people with dry mouth (xerostomia) do not include SLS. Biotene is the best known of the SLS free toothpastes. Biotene is available in most grocery stores and pharmacies in the U. S. Most people who use SLS free toothpaste will decrease the frequency of outbreaks of Aphthous ulcers. Additionally, SLS free toothpaste is more comfortable to use when sores are present. Treatments for cankers range from medicinal to metaphysical. The author recommends a few popular treatments to get rid of canker sores.

The simplest treatment is to wait for the mouth sores to heal. Avoid food and drink that irritates the sores, sleep face up so that teeth do not rub the cankers at night, and take pain relievers like Tylenol or Motrin, when necessary. The ulcers all heal within two weeks.

There are many suggestions for treating aphthae nutritionally. Some recommend taking B complex and C vitamins. Another common tip to get rid of canker sores is to eat yogurt with active cultures (lactobacillus) or even lactobacillus tablets. The author does not find nutritional additives to be a helpful, but many people support this venue.

Rinsing with warm salt water (/pages/a teaspoon of salt in a cup of warm water) is comforting and does seem to aid healing. This home remedy works for a variety of problems.

There are many covering and numbing preparations available over-the-counter and by prescription. The author prefers Orabase with Benzocaine, cyanoacrylate bandage products, and viscous lidocaine.

Orabase is a gooey paste that is able to adhere directly to canker sores. Dab a small amount onto the ulcer to provide a protective coating. Do not smear Orabase on or apply a thick coating. It lasts long enough to eat a meal. Orabase is available with Benzocaine, a popular numbing medication. Orabase is also available with a steroid, Kenalog that speeds healing. Kenalog in Orabase is expensive (about $20.00 for a 5-gram tube), requires a prescription, and must be applied several times a day.

Cyanoacrylate products are similar to Super Glue (do not use glue in the mouth; it is not safe). Products like Colgate Soothe and Seal are easy to apply. They provide a hard barrier to protect the cankers from any irritation.

Dentists prescribe viscous lidocaine for patients to use as necessary for quick relief of mouth pain from a variety of conditions. The disadvantages of viscous lidocaine are its bitter taste, that it will numb the entire mouth, and that its effect only lasts a short time. Never the less, most people appreciate viscous lidocaine for its effectiveness and ease of use.

Aphthous ulcers are a painful and bothersome oral condition. They will go away on their own. Try some of the over-the-counter and nutritional remedies. If you would like additional suggestions, or if your mouth ulcers last for more than two weeks, please consult your dentist.

For a list of OTC canker sore products, see Canker Sore   

Dr. David Leader is the Chairman of the Health Advisory Committee of the Lynnfield Schools, a member of the Professional Advisory Committee of Tri-CAP Head Start, and is a member of the Mass Dental Society Council on Dental Care and Benefits Programs.