Supplements the maxillary first premolar in function

Less angular ,rounded crown in all aspects

Single root Smaller crown

cervico-occlusally Root length is as

great or greater

Not as long as that of the first premolar

Less pointed Mesial slope is

shorter than the distal slope

Buccal ridge of the crown may not be so prominent when compared with the first premolar

Lingual cusp is longer making the crown longer on the lingual side

Cusps of second premolar are shorter with the buccal and lingual cusps more nearly the same length

Greater distance between cusp tips-that widens the occlusal surface buccolingually

No developmental depression on the mesial surface of the crown as on the first premolar

Crown surface is convex instead No deep dev. Groove crossing the mesial

marginal ridge

Outline of the crown is more rounded or oval rather than angular

Central dev. groove is shorter and more irregular

Tendency toward multiple supplementary grooves radiating from the central groove that may extend out to the cusp ridges

Makes for an irregular occlusal surface and gives a very wrinkled appearance