Mandibular first premolars

• The lingual cusp is significantly smaller than the buccal cusp
• Facially, there is a buccal ridge, cervical ridge, and shallow depressions to the sides of the buccal ridge
• An important feature is the presence of the mesiolingual developmental groove
• The lingual region is narrower than the buccal (buccolingual convergence)
• Proximally, the crown has a rhomboidal shape due to the lingual inclination of the crown
• Occlusally there are buccal and lingual triangular ridges, mesial and distal marginal ridges, and a transverse ridge running form the buccal to lingual triangular ridge
• There is a central developmental groove, but it is not as prominent as the maxillary premolars