Corpus: Premolar
Synonym: bicuspid
1. Definition
2. Nomenclature
2.1. Upper jaw (maxilla)
- 1st premolar right: Tooth 14
- 2nd premolar right: Tooth 15
- 1st premolar left: Tooth 24
- 2nd premolar left: Tooth 25
2.2. Lower jaw (mandible)
- 1st premolar left: Tooth 34
- 2nd premolar left: Tooth 35
- 1st premolar on the right: Tooth 44
- 2nd premolar right: Tooth 45
3. Anatomy
Premolars are significantly slimmer than the molars located further back. Their occlusal surface usually has 2 cusp tips, a structure referred to as "bicuspid". The buccal cusp tip is larger, while the palatal or lingual cusp tip is somewhat less pronounced. The 2nd premolars in the lower jar can have 2 cusps lingually, occasionally making them tricuspid.
Except for the maxillary first premolar, which is two-rooted in 60 to 80 % of cases, premolars are single-rooted teeth. Additionally, the first upper premolar has a kidney shape due to the relatively strong mesial concavity. Single-rooted premolars typically contain two pulp canals, which can unite towards the apex of the root.