This first maxillary premolar contains two cusps called the buccal and lingual cusps (shorter). The lingual cusp is slightly displaced to the mesial surface, and it is smaller than the buccal cusp. On the middle lobe of the buccal cusp, sometimes a buccal cusp ridge is present. It goes from either side of the cusp apex towards the mesial and distal surfaces. The buccal cusp ridge is usually straight but not parallel to the central groove that is located in the middle of the occlusal surface.

Both cusps are connected by the mesial and distal marginal ridges. The latter ridge is crossed by the mesial marginal groove, which extends approximately 1-2 mm into the mesial surface from the occlusal surface.

When viewing the first maxillary premolar from the mesial or distal surfaces, on either side of the occlusal surface can be seen V-shaped grooves formed by either distobuccal and distolingual or mesiobuccal and mesiolingual grooves.

The first maxillary premolar is narrower mesiodistally than it is buccolingually, and it has an oval occlusal outline with a very sharp mesiobuccal line angle.

The buccal surface presents with two developmental grooves (depressions) - the mesiobuccal and distobuccal grooves. On the mesial surface is located a very prominent mesial concavity (also called the mesial developmental depression) that extends from the height of contour into the root of the tooth. 

The following ridges form the borderline of the occlusal table:

• Distobuccal ridge

• Distal marginal ridge

• Distolingual ridge

• Mesial marginal ridge

• Mesiolingual ridge

• Mesiobuccal ridge

The occlusal surface contains two more ridges -  buccal triangular and lingual triangular ridges. Both ridges go from the cusp apexes towards the central groove and separate two triangular-shaped fossae located on either end of the central groove, the mesial triangular fossa and the distal triangular fossa.

The height of contour of the first maxillary premolar is as follows:

• Buccal - in the connection between the middle and cervical third;
• Palatal - in the middle third;
• Mesial and distal - between middle and occlusal thirds. 

From the height of contour, the buccal outline of this tooth is flatter, but the lingual - more rounded.

The first maxillary premolar can present with one or two roots named the buccal and lingual roots.