Canker sores, also known as aphthous ulcers, are a common oral condition. These small, shallow lesions develop inside the mouth, causing intense discomfort. While generally harmless, the pain can significantly impact daily activities like eating and speaking.
What Are Canker Sores?
Canker sores appear as small, round or oval-shaped ulcers with a distinctive white or yellowish center surrounded by a red border. They commonly form on the soft tissues inside the mouth, including the inner surfaces of the lips and cheeks, on or under the tongue, and sometimes on the soft palate. These lesions are not contagious and are different from cold sores, which are caused by a virus. Minor canker sores, the most common type, are typically less than 1 centimeter across.
The Biological Roots of the Pain
The pain from a canker sore stems from the breakdown of the oral mucosa, the protective tissue lining the mouth. When this tissue is damaged, sensitive nerve endings become exposed. This exposure means that even slight contact or changes in the mouth can trigger pain signals.
Following tissue damage, the body initiates an inflammatory response as part of its natural healing process. This involves the release of various inflammatory chemicals. These chemical mediators sensitize the exposed nerve endings and contribute to the redness, swelling, and persistent pain characteristic of canker sores. The areas where canker sores typically form, such as the inside of the cheeks and lips, are non-keratinized. This means they lack the tougher, more protective layer of keratin found on parts of the mouth like the gums or hard palate, making them more vulnerable to injury and subsequent pain when an ulcer forms.
Factors That Intensify Canker Sore Pain
Several factors can exacerbate the pain of an existing canker sore. Acidic foods, such as citrus fruits and tomatoes, or spicy and salty foods, can irritate the exposed nerve endings and inflamed tissue. This irritation can lead to a sharp increase in discomfort.
Physical irritation also intensifies pain. Actions like chewing, speaking, or accidentally biting the sore can cause mechanical trauma, leading to stinging pain. Brushing teeth vigorously can similarly aggravate the sensitive area. Saliva and bacteria in the oral cavity can further irritate the open wound, potentially delaying healing and contributing to ongoing discomfort.
Understanding the Healing Process and Pain Relief
The body heals canker sores over time. As healing progresses, new tissue regenerates and covers the exposed nerve endings. This gradually restores the protective barrier of the oral lining.
As the damaged tissue is repaired and inflammation subsides, the sensitivity of the nerve endings decreases, leading to a natural reduction in pain. For minor canker sores, this healing process typically takes about one to two weeks, with pain often lessening within a few days. Larger or more severe canker sores may take longer to heal, sometimes up to four to six weeks.