Tooth
hideTeeth (singular tooth) are small whitish structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, and chew food. Some animals, particularly carnivores, also use teeth for hunting or defense. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of tissues of varying density and hardness.
Teeth are among the most distinctive (and long-lasting) features of mammal species. Paleontologists use teeth to identify fossil species and determine their relationships. The shape of the animal's teeth are related to its diet. For example, plant matter is hard to digest, so herbivores have many molars for chewing. Carnivores, on the other hand, need canines to kill prey and to tear meat.
Mammals are diphyodont, meaning that they develop two sets of teeth. In humans, the first set (the "baby," "milk," "primary" or "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful.
Some animals develop only one set of teeth (monophyodont) while others develop many sets (polyphyodont). Sharks, for example, grow a new set of teeth every two weeks to replace worn teeth. Rodent incisors grow and wear away continually through gnawing, maintaining relatively constant length. Many rodents such as voles (but not mice) and guinea pigs, as well as rabbits, have continuously growing molars in addition to incisors.
For more information about Tooth, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with teeth
Among Apes, Teeth Are Made for the Toughest Times (w/ Video)
Dec 16, 2009 |
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(PhysOrg.com) -- The teeth of some apes are formed primarily to handle the most stressful times when food is scarce, according to new research performed at the National Institute of Standards and Technology. The findings ...
Dentistry, a high-tech version: Robots not far off, doctor says
Nov 24, 2009 |
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Robots may practice dentistry one day, but there will always be humans telling you to open wide, said a teacher on the cutting edge of tooth care.
What a grind: Bruxism at night likely a sign of stress by day
Nov 27, 2009 |
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You can practically track Steve Barkley's stress by the level of activity in his temporomandibular joint, or TMJ, the hinge joint that connects the lower jaw to the temporal bone of the skull and helps one chew, talk and ...
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Added sugar in raisin cereals increases acidity of dental plaque
Dec 18, 2009 |
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Elevated dental plaque acid is a risk factor that contributes to cavities in children. But eating bran flakes with raisins containing no added sugar does not promote more acid in dental plaque than bran flakes alone, according ...
Loud and lazy but didn't chew gum: Ancient koalas
Other Sciences / Archaeology & Fossils
8 hours ago |
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Skull fragments of prehistoric koalas from the Riversleigh rainforests of millions of year ago suggest they shared the modern koala's "lazy" lifestyle and ability to produce loud "bellowing" calls to attract mates and provide ...
Study shows nearly 1/3 of human genome is involved in gingivitis
Dec 07, 2009 |
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Gingivitis, which may affect more than one-half of the U.S. adult population, is a condition commonly attributed to lapses in simple oral hygiene habits. However, a new study shows that development and reversal of gingivitis ...
Researchers reveal ancient origins of modern opossum
Other Sciences / Archaeology & Fossils
Dec 16, 2009 |
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A University of Florida researcher has co-authored a study tracing the evolution of the modern opossum back to the extinction of the dinosaurs and finding evidence to support North America as the center of ...
New forensic technique gives clues about sharks from bite damage
Dec 01, 2009 |
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Hit-and-run attacks by sharks can be solved with a new technique that identifies the culprits by the unique chomp they put on their victims, according to a University of Florida researcher and shark expert.
French find puts humans in Europe 200,000 years earlier
Other Sciences / Archaeology & Fossils
Dec 15, 2009 |
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Experts on prehistoric man are rethinking their dates after a find in a southern French valley suggested our ancestors may have reached Europe 1.57 million years ago: 200,000 years earlier than we thought.
New technology helps scientists understand ancient fossils
Other Sciences / Archaeology & Fossils
Dec 07, 2009 |
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Some of the world's oldest human bones and other ancient relics are studied here using some of the world's newest technologies.
Older dental fillings contain form of mercury unlikely to be toxic
Dec 09, 2009 |
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A new study on the surface chemistry of silver-colored, mercury-based dental fillings suggests that the surface forms of mercury may be less toxic than previously thought. It appears online in ACS' journal ...
Can cleft palate be healed before birth?
Dec 01, 2009 |
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In a study newly published in the journal Development, investigators at the USC School of Dentistry describe how to non-surgically reverse the onset of cleft palate in fetal mice - potentially one step in the journey to a b ...
Earliest toothless bird found
Other Sciences / Archaeology & Fossils
Dec 10, 2009 |
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(PhysOrg.com) -- A new species of bird from the Cretaceous period in China has been identified. It had toothless upper and lower jaws, and provides significant information on the diversification in the evolution ...
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