There are two premolar or bicuspid teeth in each quadrant of the jaw, four in the upper arch and four in the lower. Located between the canines and the molars, premolar teeth are absent in early childhood. The teeth appear between the ages of 10 and 12 years. Instead of single roots like the other premolars, the upper first premolars have two roots. Consequently root canal therapy, if ever required, is more complicated when undertaken on the premolars.