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dentition
dentition kind, number, and arrangement of the teeth of humans and other animals. During the course of evolution, teeth were derived from bony body scales similar to the placoid scales on the skin of modern sharks. Tooth structures such as those found in humans are restricted to certain vertebrates, i.e., most fish, mammals, and reptiles, and some amphibians. The teeth of sharks, which are primitive vertebrates, consist of simple conelike structures, sometimes with serrated edges and sometimes flattened for crushing shelled prey. In many lower vertebrates the individual teeth are replaced throughout the animal's life; old tooth loss and new tooth growth follow wavelike patterns down the length of jaw and affect alternate teeth at any one time, so that half the teeth in a region are always functional. Fish and reptiles that have teeth have homodont dentition; that is, all teeth are identical. The mammals have heterodont dentition, or teeth of different basic types, including incisors for nipping or cutting, canines for piercing, and premolars and molars for shearing and grinding. Carnivorous animals have relatively small incisors, used for grasping rather than for cutting; long and strong canines; and relatively thin, sharp premolars and molars, used for severing muscle and other tissues. Herbivorous animals have well-developed incisors, used to cut grass and other vegetation; canines that are either smaller than those of carnivores or absent altogether; and broad, flat premolars and molars for grinding food. In some herbivores, the upper canines are absent, so they cut vegetation by the combined action of the tongue and lower incisors. Omnivorous animals such as man have less specialized dentition. Only part of the dentition of mammals is usually replaced; however, the incisors of rodents grow out at the base as fast as they wear down at the tip. Teeth, the hardest structures in the body, have been well preserved as fossils and have played an important role for paleontologists and physical anthropologists in the study of human evolution. |
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"dentition." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "dentition." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-dentitio.html "dentition." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-dentitio.html |
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dentition
dentition Type, number, and arrangement of teeth. An adult human has 32 teeth. In each jaw are four incisors, two canines, four premolars, four molars and, in most adults, up to four wisdom teeth. Children lack the premolars and four molars. The incisors are used for cutting; the canines for gripping and tearing; the molars and premolars for crushing and grinding food. A herbivore has relatively unspecialized teeth that grow throughout life to compensate for wear, and are adapted for grinding. A carnivore has a range of specialized teeth related to killing, gripping, and crushing bones. In carnivores, unspecialized milk teeth are replaced by specialized adult teeth, which have to last a lifetime.
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"dentition." World Encyclopedia. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "dentition." World Encyclopedia. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O142-dentition.html "dentition." World Encyclopedia. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-dentition.html |
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dentition
dentition (den-tish-ŏn) n. the number, type, and arrangement of the teeth as a whole in the mouth. permanent d. the 32 teeth usually present by the age of 21, made up of incisors, canines, premolars, and molars. primary d. the teeth of young children, which are progressively lost in preparation for the eruption of the permanent teeth. It consists of 20 teeth, made up of incisors, canines, and molars only.
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"dentition." A Dictionary of Nursing. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "dentition." A Dictionary of Nursing. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O62-dentition.html "dentition." A Dictionary of Nursing. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-dentition.html |
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dentition
dentition In bivalve Mollusca, the articulating tooth-and-socket system in the shell hinge system. Various types may be recognized, e.g. desmodont, dysodont, heterodont, isodont, pachydont, schizodont, and taxodont.
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AILSA ALLABY and MICHAEL ALLABY. "dentition." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "dentition." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O13-dentition.html AILSA ALLABY and MICHAEL ALLABY. "dentition." A Dictionary of Earth Sciences. 1999. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-dentition.html |
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dentition
dentition The type, number, and arrangement of teeth in a species. This can be represented concisely by a dental formula. See also permanent teeth; diphyodont; monophyodont; polyphyodont; heterodont; homodont.
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"dentition." A Dictionary of Biology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "dentition." A Dictionary of Biology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O6-dentition.html "dentition." A Dictionary of Biology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-dentition.html |
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dentition
den·ti·tion / denˈtishən/ • n. the arrangement or condition of the teeth in a particular species or individual. |
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"dentition." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "dentition." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-dentition.html "dentition." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-dentition.html |
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