The last molars at the back of the jaw are known as “wisdom teeth”. If  the wisdom teeth have grown in correctly (usually occurring between the 18th and 30th year of life)  and there is sufficient room for them in the jaw, they can indeed serve as useful elements in mastication.
If this is not the case however, their surgical removal must be considered.
Retained or impacted wisdom teeth have no space in the jaw.  In their vain attempt to break through, they can damage neighbouring teeth and alter the position of the remaining ones.They can also cause considerable pain thereby necessitating their prompt removal.
As in any operation, questions of possible risks such as periodic nerve pain and/or damage to the maxillary sinus, as well as the possibility of after-bleeding must be weighed and considered beforehand, even when the probability of such occurrence appears slight. These risks are weighed against the foreseeable damage that retention of the wisdom teeth might cause and only after clarification and with the consent of the patient  is the operation be undertaken.
The older a person is the more difficult it becomes to remove wisdom teeth. If extraction is indicated it is best not to procrastinate too long in doing so.