cusp

The premolars are directly distal to (behind) the canines. Generally there are two premolars in each quadrant. Counting backward from the front of the jaw, there are normally two adult incisors, one canine, and then the two premolars, making them the fourth and fifth teeth in each row.

In anthropology, we number these teeth differently from dentists, because the premolars in humans are homologous with the distal premolars in other mammals. So the human premolars are called the third and fourth premolars, even though we have only two of them! The lowers are numbered P₃ and P₄; the uppers P³ and P⁴.

Premolars usually have two distinct points, or cusps, on their occlusal surface. In humans the lower third premolar is sometimes shaped very much like a canine tooth with only one cusp. In many primates, the P₃ has only one large cusp that cuts against the distal edge of the upper canine, like a scissors.

Examine the premolars at this station, both upper and lower. Learn to distinguish these from the other teeth.

The two incisors, one canine, two premolars and three molars on both top and bottom are called the human dental formula. We write a dental formula as follows: