Related topics: dinosaurs · fossil

Researchers find shark teeth made of natural fluoride

(Phys.org) -- German researchers studying shark teeth have found at least two species that have fluorinated calcium phosphate - mineral fluoroapatite, as a main component, one of the main ingredients in toothpaste, which ...

Ancient teeth raise new questions about the origins of modern man

Eight small teeth found in a cave near Rosh Haain, central Israel, are raising big questions about the earliest existence of humans and where we may have originated, says Binghamton University anthropologist Rolf Quam. Part ...

Why birds don't have teeth

Why did birds lose their teeth? Was it so they would be lighter in the air? Or are pointy beaks better for worm-eating than the jagged jaws of dinosaur ancestors?

Chimp filmed cleaning dead son's teeth

(Phys.org)—A trio of researchers from the U.K., the Netherlands and the U.S. has filmed a grown female chimpanzee cleaning her son's teeth after he died. In their paper published in the journal Scientific Reports, Edwin ...

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Tooth

Teeth (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.

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