Hygiene Atlas

Atlas · Plate II · Dental Anatomy and Tooth Morphology · 06

Premolars

The eight premolars replace the primary molars and have no counterpart in the primary dentition. The maxillary first premolar usually has two roots and a prominent mesial concavity on crown and root; the maxillary second has one root and nearly equal cusps. The mandibular first premolar's small lingual cusp makes it look like a canine, and the mandibular second most often has three cusps.

High-yield facts · 7

  1. Premolars are 8 in all, replace the primary molars and are absent from the primary dentition.T6
  2. Maxillary first premolar: two roots (buccal and palatal) in most cases; a prominent mesial crown and root concavity (mesial developmental depression).T6
  3. Maxillary first premolar: buccal cusp is longer than the lingual; the mesial cusp ridge of the buccal cusp is longer than the distal (unlike the canine).T6
  4. Maxillary second premolar: usually one root; cusps nearly equal in height.T6
  5. Mandibular first premolar: small, nonfunctional lingual cusp; mesiolingual groove is common.T6
  6. Mandibular second premolar: the 3-cusp (Y groove) form is more common than the 2-cusp (H or U groove) form.T6
  7. The mandibular second premolar's root is close to the mental foramen.S68

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.