If I have my wisdom teeth extracted, is it possible that the teeth will grow back? I don't want to do this more than once!

Possible. A tooth develops from a bud of tissue in the jaws. The crown develops first, followed by the development of the root. If a partially developed wisdom tooth is removed and the residual follicle of tissue that the tooth developed from is not removed, the residual follicle or bud has the capability of continuing to develop into a tooth.
The. The actual teeth that are extracted will never grow back. In rare cases, a person can have an extra tooth which has not yet erupted - but your dentist would be able to tell you if there was an extra tooth by looking at your dental xrays.