Grown persons can have up to 32 teeth. The wisdom teeth are the last to come through, right at the back. They generally become visible when you are between 17 and 25, even though occasionally they appear many years later.
These days people often have jaws that are too small for all 32 teeth - 28 is often the most we have room for. So if all the other teeth are present and healthy there may not be enough room for the wisdom teeth to come through correctly.
What are the main reasons for taking wisdom teeth out?
When it is obvious that the wisdom teeth will not be able to come through into a practical position because there is not enough space, and they are also causing some ache or anxiety.
If they have only partly come through and are decayed such teeth will often be more likely to decay as it will be difficult to clean them as thoroughly as your other teeth.
If the wisdom tooth is causing a cleaning difficulty and has no real utilize.
If they are aching.