Permanent teeth or adult teeth are the second set of teeth formed in diphyodont mammals. The four last permanent teeth, the third molars, usually appear between the ages of 17 and 38 years; they are considered wisdom teeth.
Have you ever wondered why we only grow two sets of teeth? Why don't we grow a third set around middle age? Here are the facts that may surprise you.
That could help explain why 92% of American adults have tooth decay in We may never evolve to grow a third set of teeth, but that hasn't.