Premolar
A premolar ( Dens premolaris , Pl. Dentes praemolares ), also premolar tooth , is a molar tooth in the teeth of mammals . A synonym is the term bicuspid (from Latin to "twice" and cuspis "tip"). In contrast to the molars , premolars also have deciduous teeth that perform the grinding function before changing teeth .
In the mammalian ancestors there were originally four premolars in each half of the jaw , so a total of 16. This number is reduced in most modern mammals. In humans, only two premolars are formed , and in rodents (with the exception of the guinea pig relatives ) there are no more premolars. Ruminants have three premolars, they lack the first.
Premolars of Man
The human premolars have two to three cusps. Lower premolars have a very pronounced crown alignment . The number of tooth roots and root canals is shown in the following table, although deviations are possible:
teeth | Number of tooth roots | Number of root canals | Number of humps |
---|---|---|---|
14, 24 | 1 2 (> 60%) 3 |
1 (9.0%) 2 (85.0%) 3 (6.0%) |
2 |
15, 25 | 1 (> 85%) 2 |
1 (75.0%) 2 (24.0%) 3 (1.0%) |
2 |
34, 44 | 1 (74.0%) 2 (26.0%) |
1 (73.5%) 2 (26.0%) 3 (0.5%) |
2 (75%) 3 (25%) |
35, 45 | 1 (85.0%) 2 (15.0%) |
1 (85.5%) 2 (13.0%) 3 (0.5%) |
3 |
The human dentition (scheme, each tooth in two views)
See also
Web links
Individual evidence
- ^ Gert-Horst Schuhmacher, Anatomie, Textbook and Atlas, 2nd edition 1991, Barth-Verlag. ISBN 3-335-00264-4 .
- ^ John I. Ingle, Leif K. Bakland, Endodontics, Williams & Wilkins, Philadelphia, 4th Sub edition (1994), ISBN 0-683-04310-2 .
- ↑ JR Strube, M. Stern, Curriculum Prothetik, Volume I, Quintessenz Verlag, 2011, pp. 32–33. ISBN 3-86867-026-2 .