Molar Intercuspal Dimensions: Genetic Input to Phenotypic Variation

@article{Townsend2003MolarID,
  title={Molar Intercuspal Dimensions: Genetic Input to Phenotypic Variation},
  author={G. C. Townsend and Lindsay C. Richards and Toby E Hughes},
  journal={Journal of Dental Research},
  year={2003},
  volume={82},
  pages={350 - 355}
}
Molecular studies indicate that epigenetic events are important in determining how the internal enamel epithelium folds during odontogenesis. Since this process of folding leads to the subsequent arrangement of cusps on molar teeth, we hypothesized that intercuspal distances of human molar teeth would display greater phenotypic variation but lower heritabilities than overall crown diameters. Intercuspal distances and maximum crown diameters were recorded from digitized images of dental casts in… 
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References

SHOWING 1-10 OF 28 REFERENCES

Genetic and environmental contributions to variation in human tooth size

TLDR
There were significant levels of non-additive genetic variation in MD diameters of canines and first premolars, which is consistent with selective pressures acting on these teeth at some stage in human evolution.

Intercuspal Distances of Maxillary Pre-molar Teeth in Australian Aboriginals

TLDR
It appears that the sex differences, which are observed in overall crown dimensions, are established after the cusp tips are localized, and intercuspal distances appear to have a strong genetic component of variability, although they show high phenotypic variability and fluctuating asymmetry.

Genetic analysis of deciduous tooth size in Australian twins.

Individual variation in enamel structure of human mandibular first premolars.

  • D. SternZ. Skobe
  • Medicine, Materials Science
    American journal of physical anthropology
  • 1985
TLDR
It was concluded that within this tooth type, there is a large amount of individual variation not only in gross morphology but also in enamel ultrastructure, which underscores the fact that interspecific comparisons must be made with care.

Genotype, phenotype, and developmental biology of molar tooth characters.

TLDR
The whole cusp pattern is a product of a dynamic developmental program manifested in the activation of the developmental modules, and this patterning cascade mode of cusp development can be used to explain the variational properties of dental characters and character states related to cusp initiation.

Model for the examination of evolutionary trends in tooth development.

TLDR
Serial C-t scans were used to compare two distinct developmental stages represented by the dentine-enamel junction (DEJ) and outer enamel surface (OES), respectively, in mandibular DM2 and M1 of 31 archaeological specimens, supporting the hypothesis that differences between the two teeth increase throughout development.

A gene network model accounting for development and evolution of mammalian teeth

TLDR
Large morphological effects frequently can be achieved by small changes, according to this model, and similar morphologies can be produced by different changes, consistent with why predicting the morphological outcomes of molecular experiments is challenging.

Morphologic Relationships Between Enamel and Dentin Surfaces of Lower First Molar Teeth

  • B. S. Kraus
  • Medicine, Materials Science
    Journal of dental research
  • 1952
TLDR
In order to ascertain whether or not complete topical and metrical correspondences exist between the enamel and dentin surfaces, a study was made of 50 lower first molars, and it was assumed that the daily rate of formation of enamel proceeds uniformly throughout theEnamel crown.

Three-dimensional measurement of the morphological relationship between molar occlusal surface and enamel-dentin junction

TLDR
The results indicated that the volume of enamel in M3 was smallest among the three lower molars, and the differences in the thickness of the enamel between the region of the cuspal tip and the groove were shown to be related to the Differences in the heights of thecusps between the EDJ and theEnamel surface.

Comparison of the development of the second deciduous molar and first permanent molar in man.

  • P. M. Butler
  • Environmental Science
    Archives of oral biology
  • 1967