The buccal cusp of the first maxillary premolar has a buccal cusp ridge that goes from either side of the buccal cusp tip 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 occlusal surface contains two more ridges - the buccal triangular ridge and lingual triangular ridge. Both triangular ridges go from the cusp tips towards the central groove.

A few more ridges extend from the sides of the buccal and lingual cusp tips towards the mesial and distal surfaces. They are named after the cusp on which they are located and the surface towards which they go. The buccal cusp has the mesiobuccal and distobuccal cusp ridges, while the lingual cusp presents with the mesiolingual and distolingual cusp ridges.

Overall, the following ridges form the borderline of the occlusal table:

Distobuccal cusp ridge
Distal marginal ridge
Distolingual cusp ridge
Mesiolingual cusp ridge
Mesial marginal ridge
Mesiobuccal cusp ridge

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First maxillary premolar (part 2)