Related topics: dinosaurs · fossil

Rinsing system in stomach protects the teeth of ruminants

When they graze, goats, sheep and cows often ingest bits of earth that can be damaging to their teeth. Researchers from the University of Zurich have now shown how the animals protect themselves against dental abrasion: Their ...

Snowflakes inform scientists how tooth enamel is formed

Physicists and mathematicians use the classical Stefan problem to explain the principles of crystal formation, such as those that create snowflakes . Researchers in the University of Helsinki and Aalto University have now ...

3-D technology looks into the distant past

Researchers from the University of Tübingen and their colleagues from Switzerland have studied hundreds of fossil carp teeth for the first time using 3-D technologies. In 4 million-year old lake sediments from what is now ...

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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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