A popular name for the last molar tooth on either side of each jaw . These teeth are the last to appear and should develop in early adult life, but often they do not cut the gum till the age of 20 or 25; indeed, they may sometimes remain permanently impacted in the jaw-bone. This occurs in up to 25 per cent of individuals. The lower third molar is often impacted against the second because of the direction in which it erupts.
