The wisdom teeth are the third molars, that are the last teeth to erupt in your mouth. The age of eruption of wisdom teeth, is approximately 17 years to 21 years. Any wisdom tooth that do not erupt at their proper position but are present in the jaw are called Impacted teeth.
Most of the times there are 4 wisdom teeth in our mouth, 2 in the upper jaw and 2 in the lower jaw. But sometimes, some people do not have all of them.
An impacted wisdom tooth can either be completely inside the jaw bone, or break through the soft tissue partially. The tooth can erupt in different angulation which causes the tooth to get stuck in the jaw bone many times. Another cause for the tooth to be impacted is less space available for the tooth as it is the last one to erupt. According to many theories, evolution has caused the jaw size in humans to decrease leaving less space for wisdom tooth to erupt.