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► Health Information LibraryCanker sore (aphthous ulcer)

Canker sore (aphthous ulcer)

Canker sores (Aphthous ulcers) are very common. Typically, they are a shallow ulcer with a white or whitish/yellow base surrounded by a reddish border. This severe form of ulcerĀ can beĀ seen in an individual with AIDS and is located in front and just below the bottom teeth.