Generally, the front, incisor and canine teeth have one canal, premolars have two canals and the back molar teeth have three.
All animals in this order lack incisor and canine teeth, but they may have numerous simple molars in the backs of their jaws.
In contrast to man, apes tend to have large incisor and canine teeth which are relatively larger than their molars.
During the teenage years, boys and girls get each of their top four incisor teeth filed to a point.
During the struggle it is believed the woman may have knocked out the man's lower front incisor - such a tooth was found at the scene and is being examined by forensic experts.
He opened his mouth to show a gap in the front of his mouth where an incisor should have been.
Two more chimpanzee teeth were later found at the site, an upper incisor and a tooth tentatively identified as a molar.
The first measurements they took were the length of the hard palate, from the first premolar to the last incisor .
Those are the things that the front teeth, the incisors act on in order to regulate the bite size that goes into the mouth.
Billy has been left with only eight back teeth and his two front incisors , which dentists say are so badly decayed they will fall out in months.