Molarization

Sometimes premolars have a root morphology similar to that of molars, a phenomenon known as molarization. Thus lower premolars will have a mesial and a distal root just like lower molars, and upper premolars have two buccal roots and one palatal root just like upper molars. The crowns in these premolars with molarization usually look quite normal, particularly in the upper premolars. Sometimes there may be an extra cusp present and the crown may be slightly longer mesio-distally.

The frequency of molarization in premolars is approximately 1%. In the maxilla it is more frequent in the first premolar whereas in the mandible it is more frequent in the second premolar. These teeth usually have three root canals, but mandibular premolars can sometimes have only two.