They are, as stated, four large teeh that grow at the rear af the adult jaw - hence the idea that they are 'wisdom' teeth, only gained in adulthood. Not everyone grtows them, but some people get 'impacted' wisdom teeth that start to grow out at odd angles, and are painful. The solution is extraction, which, given the size of the teeth, can be best performed under general aenesthetic, which dentists no longer use, and may therefore require a hospital visit.