Causes of Canker sore? 

The exact cause of canker sore is unknown. Factors that provoke them include stress, fatigue, illness, injury from accidental biting, hormonal changes, menstruation, sudden weight loss, food allergies, the foaming agent in toothpaste (SLS) and deficiencies in vitamin B12, iron and folic acid. Some drugs, such as nicorandil, also have been linked with mouth ulcers. In some cases they are thought to be caused by an overreaction by the body's own immune system. Trauma to the mouth is the most common trigger of canker sore. Physical trauma, such as that caused by toothbrush abrasions, laceration with sharp foods or objects, accidental biting (particularly common with sharp canine teeth), or dental braces can cause mouth ulcers by breaking the mucous membrane. Other factors, such as chemical irritants or thermal injury, may also lead to the development of ulcers. The large majority of toothpastes contain Sodium lauryl sulfate (SLS), which is known to cause cankers in certain individuals. Some studies find no connection between SLS in toothpaste and mouth ulcers. Artificial sugars, such as those found in diet cola and sugarless gum, have been reported as causes of aphthous ulcers as well. They can also be linked to an increased intake of acids such as ascorbic acid (one form of Vitamin C) or citric acid. In this case the sores disappear after intake decreases (for example, by substituting ascorbate salts for ascorbic acid). There is a commonly held belief that another cause of canker sore is gluten intolerance (Celiac disease), whereby consumption of wheat, rye, barley and sometimes oats can result in chronic mouth ulcers. However, two small studies of patients with Celiac disease have demonstrated no link between the disease and aphthous ulcers. Although the exact cause is not known, canker sores are thought to form when the body becomes aware of and attacks molecules which it does not recognize. The presence of the unrecognized molecules garners a reaction by the T-cells, which trigger a reaction that causes the damage of a mouth ulcer. People who get these ulcers have lower numbers of regulatory T-cells. Repeat episodes of canker sores can be indicative of an immunodeficiency, signalling low levels of immunoglobulin in the mucous membrane of the mouth. Certain types of chemotherapy cause mouth ulcers as a side effect. Mouth ulcers may also be symptoms or complications of several diseases.

Answered by cuteguy , an ibibo Master, at 8:17 PM on November 20, 2007

Canker sores are painful sores in the mouth that may be caused by a variety of different agents. It is not always possible to identify the cause of canker sores, and most physicians will list a number or reasons why canker sores might form. There is no one clear cause, but rather a series of exposures, trauma or predisposing conditions that can result in canker sores. It is known that white blood cells attack the mouth in certain spots, and thus those with autoimmune disorders may be more prone to sores. Some canker sores may be precipitated by trauma to the mouth. Such trauma might include biting the side of one’s cheek, or eating crunchy foods like chips or French bread that might cause a small cut in the mouth. The well-known sourdough bread of San Francisco often sends tourists to the doctor for mouth sores. These small cuts may not develop into canker sores, but often those with sores can recall some trauma to the mouth prior to development of a sore. Some canker sores have been linked to toothpastes and mouthwashes that contain sodium lauryl sulfate. This ingredient is included in many brands and is thought to make the mouth dryer, predisposing the unlubricated mouth to form canker sores. Usually switching to toothpaste that does not contain sodium lauryl sulfate can reduce sores. Some physicians feel that people with a high degree of stress may be more prone to canker sores. Like acne breakouts that appear with stress, canker sores may also be caused by periods of intense stress. Perhaps higher respiratory rates at this time may cause the mouth to be drier. As well, medications taken for stress, like tranquilizers or sleep aids produce significant dry mouth. When the mouth is not well lubricated, sores are more likely to appear. Some vitamin deficiencies might cause canker sores. Medical researchers have found that low levels of variants of vitamin B and vitamin C can cause sores. Often the B complex vitamins are also used to treat stress or emotional disturbance, so it is hard to say whether the predisposing condition of canker sores is lack of vitamin B or presence of stress, or both. Food allergies may also cause canker sores. Particularly allergies to acidic foods like tomatoes and oranges may be responsible for developing sores. As well, allergies to milk, grains, and chocolate can be causal factors. Canker sores might result from viruses or bacterial infection. Those experiencing chemotherapy also have a high risk for these mouth ulcers. Serious viruses like HIV can cause very long-lasting and painful sores, and may indicate a reduction in the ability to fight off infections. Treatment of canker sores usually depends upon cause, which is not always identifiable. Most doctors recommend finding different toothpaste that does not contain sodium lauryl sulfate. As well, over the counter topical medications for sores can help reduce pain. Where bacterial infection is suspected, antibiotics may be used to resolve sores. Since most sores have no known origin, doctors usually recommend using a topical pain reliever if necessary. One can expect to see the sore resolve within two weeks. Those who have multiple sores, sores that last longer than two weeks, or fever, should see a doctor to rule out infection or illness.

Answered by Pammu , an ibibo Specialist, at 6:45 PM on November 20, 2007

The cause of most canker sores remains a mystery. Researchers generally believe that stress or tissue injury may cause the eruption of canker sores. A minor injury — caused by biting the inside of your mouth or by eating rough foods, such as nuts — may trigger a canker sore. Other causes may include: * Faulty immune system function * Nutritional problems, such as a deficiency of vitamin B-12, zinc, folic acid or iron * A disease of the gastrointestinal tract * Food allergies * Menstrual periods Though anyone can get cankers sores, they tend to run in families and may be an inherited condition.

Answered by Romi , an ibibo Master, at 5:38 PM on November 20, 2007