premolar teeth are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. [1 ] [2 ] They have at least two [3 ] cusps. Premolars can be considered as a 'transitional tooth' during chewing, or mastication. It has properties of both the anterior canines and posterior molars, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. [4 ]
The premolars in humans are the
maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. [1 ] [3 ]
There is always one large
buccal cusp, especially so in the mandibular first premolar. The lower second premolar almost always presents with two lingual cusps. [5 ]
Molar teeth by definition are permanent teeth
distal to the canines, preceded by deciduous premolars. In primitive [6 ] placental mammals there are four premolars per quadrant. The most mesial two have been lost in Catarrhines ( Old World monkeys and apes, including humans). Paleontologists refer to human premolars as Pm3 and Pm4. [7 ]
Additional images [ edit ]
Mouth (oral cavity)
Left maxilla. Outer surface.
Base of skull. Interior surface.
See also [ edit ]
References [ edit ]
^ a b Roger Warwick & Peter L. Williams, ed. (1973), Gray’s Anatomy (35th ed.), London: Longman, pp. 1218–1220
^ Weiss, M.L., & Mann, A.E (1985), Human Biology and Behaviour: An anthropological perspective (4th ed.), Boston: Little Brown, pp. 132–135, 198–199, ISBN 0-673-39013-6
^ a b Glanze, W.D., Anderson, K.N., & Anderson, L.E, ed. (1990), Mosby's Medical, Nursing, and Allied Health Dictionary (3rd ed.), St. Louis, Missouri: The C.V. Mosby Co., p. 957, ISBN 0-8016-3227-7
^ Weiss, M.L., & Mann, A.E. (1985), pp.132-134
^ Warwick, R., & Williams, P.L. (1973), p.1219.
^ Warwick, R., & Williams, P.L. (1973), pp.1218-1219.
^ Christopher Dean (1994). "Jaws and teeth". In Steve Jones, Robert Martin & David Pilbeam (eds.). The Cambridge Encyclopedia of Human Evolution. Cambridge: Cambridge University Press. pp. 56–59. ISBN 0-521-32370-3. Also ISBN 0-521-46786-1 (paperback)