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A curriculum vitae of teeth: evolution, generation, regeneration.

Koussoulakou DS, Margaritis LH, Koussoulakos SL - Int. J. Biol. Sci. (2009)

Bottom Line: Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity.In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased.These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors.

View Article: PubMed Central - PubMed

Affiliation: University of Athens, Faculty of Biology, Department of Cell Biology and Biophysics, Athens, Greece.

ABSTRACT
The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration.

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Related in: MedlinePlus

Evolution of the tribosphenic teeth. Diagram explaining the evolution of the in-straight-line cusps of upper molars (left), to shaping the triangle (right) aiming to better grinding of the food. (parac=paracone, protoc=protocone and metac=metacone).
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Figure 2: Evolution of the tribosphenic teeth. Diagram explaining the evolution of the in-straight-line cusps of upper molars (left), to shaping the triangle (right) aiming to better grinding of the food. (parac=paracone, protoc=protocone and metac=metacone).

Mentions: The evolution of the mammalian jaw and teeth created occlusal surfaces that are adequate for a great variety of foods. For example, Triconodont organisms were endowed with teeth bearing three major cusps in a (more or less) straight line (Fig. 2) and other smaller cusps on an external, rounded cingulum. This arrangement increases the ability of the teeth to crush and grind food, thus giving rise to mastication. In Symmetrodont organisms (extinct mammals), the central cusp was separated from the other two outer cusps so that a triangle was formed on the occlusal surface of the upper molars; later, comparable, geometrically complementary structures were formed on the occlusal surface of the lower molars too, resulting in a dramatic increase in the masticatory efficiency of the molars 34, 35.


A curriculum vitae of teeth: evolution, generation, regeneration.

Koussoulakou DS, Margaritis LH, Koussoulakos SL - Int. J. Biol. Sci. (2009)

Evolution of the tribosphenic teeth. Diagram explaining the evolution of the in-straight-line cusps of upper molars (left), to shaping the triangle (right) aiming to better grinding of the food. (parac=paracone, protoc=protocone and metac=metacone).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2651620&req=5

Figure 2: Evolution of the tribosphenic teeth. Diagram explaining the evolution of the in-straight-line cusps of upper molars (left), to shaping the triangle (right) aiming to better grinding of the food. (parac=paracone, protoc=protocone and metac=metacone).
Mentions: The evolution of the mammalian jaw and teeth created occlusal surfaces that are adequate for a great variety of foods. For example, Triconodont organisms were endowed with teeth bearing three major cusps in a (more or less) straight line (Fig. 2) and other smaller cusps on an external, rounded cingulum. This arrangement increases the ability of the teeth to crush and grind food, thus giving rise to mastication. In Symmetrodont organisms (extinct mammals), the central cusp was separated from the other two outer cusps so that a triangle was formed on the occlusal surface of the upper molars; later, comparable, geometrically complementary structures were formed on the occlusal surface of the lower molars too, resulting in a dramatic increase in the masticatory efficiency of the molars 34, 35.

Bottom Line: Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity.In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased.These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors.

View Article: PubMed Central - PubMed

Affiliation: University of Athens, Faculty of Biology, Department of Cell Biology and Biophysics, Athens, Greece.

ABSTRACT
The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration.

Show MeSH
Related in: MedlinePlus