Aphthous ulcer
Aphthous ulcer: A small sensitive painful ulcer crater in the lining of the mouth.
Commonly called a canker sore.
Aphthous ulcers are one of the most common problems that occur in the mouth.
About 20% of the population (1 in 5 people) have aphthous ulcers at any given time.
Aphthous ulcers typically last for 10-14 days and they heal without leaving a scar.
There are many possible causes of aphthous ulcers.
Often the cause is unknown.
For a full article, see Canker sores (Aphthous ulcers).