Dental Anatomy: Permanent mandibular 2nd premolar

Permanent mandibular 2nd premolar:
?The function of this premolar is to assist the mandibular first molar during mastication “chewing”. The mandibular first premolar resembles a small canine, while the mandibular second premolar is more alike to the first molar.
?Mandibular second premolars most commonly have three cusps. There is one large cusp on the buccal side. The lingual cusps are well developed and functional.
?There are no deciduous mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.
The Contact Points; Height of Curvature:
? From the facial, the mesial contact is more occlusal than the distal contact. The distal marginal ridge is lower than the mesial marginal ridge.
Right and Left:
? In the two cusp version, the lingual cusp tip is shifted mesially. In the three cusp version, the larger of the two lingual cusps is to the mesial.
Root:
? The mandibular second premolar has a single root that is usually larger and longer than that of the first premolar.
Variation:
? There may be one or two lingual cusps.
? This tooth is sometimes missing, however only the third molars and upper lateral incisors are missing more frequently than this tooth.