Occasionally after one has received dental treatment an ulcerative sore on the gums or inside the mouth may occur. This sore is known as an aphthous ulcer or canker sore. It appears as a round yellowish or whitish ulceration on the lips, cheeks, tongue, and/or floor of the mouth. It can be single or multiple in number. The area is often painful.

The exact cause of canker sores is unknown. However, it is believed that certain immune factors such as stress, chemical or physical insult, food or liquid sensitivity, change in sleeping patterns, etc., all of which dental treatment can naturally affect, can induce the formation of canker sores. Even biting the inside of the cheek or tongue, brushing, flossing, or chewing sharp, hard foods can trigger a canker sore. These sores are not contagious.

Treatment is primarily symptomatic and palliative, focusing on making the child more comfortable eating and drinking. An over-the-counter topical paste such as Orabase by Colgate or Zilactin can be applied to the ulcer two to four times a day especially before meals. This will protect and cover the ulcer from irritation by liquids or foods and allow the ulcer to heal spontaneously. With or without medication, healing will take about seven to ten days.

Avoid salty, spicy, or hot liquids and foods. Toothpaste may cause irritation to the ulcer, but every effort to keep the surrounding area and teeth clean is essential. An over-the-counter, aspirin-free analgesic medication may be used as necessary according to product directions for pain relief.