Ophthalmology

Blind man sees with help from tooth-implanted lens

(Medical Xpress)—In 1998, Ian Tibbets lost vision in his right eye, some time after he severely injured the cornea with a piece of scrap metal. Later on he also lost vision in his left eye. Tibbets was eventually referred ...

Genetics

Genes could play a role in tooth decay and gum disease

Tooth decay and gum disease impact on illness and healthcare spending, yet the role of genetics in dental problems is largely unknown. New research led by an international team, including researchers at the University of ...

Neuroscience

Study: Protein key to charcot-marie-tooth, other nerve diseases

A new study provides critical insight into a little-known, yet relatively common, inherited neurological condition called Charcot-Marie-Tooth disease. The findings point to a pathway to possible treatments for this disease ...

Dentistry

Regrowing dental tissue with stem cells from baby teeth

Sometimes kids trip and fall, and their teeth take the hit. Nearly half of children suffer some injury to a tooth during childhood. When that trauma affects an immature permanent tooth, it can hinder blood supply and root ...

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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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