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teeth
Adj. dental
Tuesday 25 November 2003
tooth Adj; dental
| WKP |
Definition : A tooth (plural teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes.
The roots of teeth are covered by gums.
Teeth are not made of bone, but rather of multiple tissues of varying density and hardness. The cellular tissues that ultimately become teeth originate from the embryonic germ layer, the ectoderm.
Embryology
Teeth develop from epithelial cells from the mucosal lining of the oral cavity and cranial neural crest-derived ectomesenchymal cells. The epithelial part forms the cap-shaped enamel organ consisting of an inner side of high cylindrical inner enamel epithelium that differentiates into enamel-forming ameloblasts, an external surface consisting of cuboidal outer enamel epithelium and an intervening loose epithelial structure known as stellate reticulum.
The ectomesenchymal part that is enclosed by the enamel organ is known as the dental papilla: dental papilla cells at the border with the inner enamel epithelium develop into dentin-forming odontoblasts. Both enamel organ and dental papilla together are surrounded by a fibrous capsule, the dental sac or dental follicle.
As the enamel organ elongates through downward proliferation, it creates a tube that maps out the form and size of the roots of the teeth.
Therefore, remnants of odontogenic epithelium can be found in the jaw bone at a level as deep as the root tips of the teeth.
Those that lie in the connective tissue that connects the tooth with the jaw, the so-called periodontal ligament, are known as rests of Malassez. Corresponding epithelial remnants in the gingiva are named rests of Serres.
Pathology
dental malformations
dental anomalies
dental diseases
dental tumors
Videos
Tooth developement (by Washington Deceit)
Tooth eruption (by Washington Deceit)
See also
dental development
dental germ
References
Peters H, Balling R. Teeth. Where and how to make them. Trends Genet. 1999 Feb;15(2):59-65. PMID: 10098408
