Author

Ophir Klein

Additional Author(s): Andrew H. Jheon, Kerstin Seidel, Brian Biehs

Published on SDB CoRe: Jun 22 2012

Morphogenesis: Cell Movements
Ectoderm-derived: Neural Crest
Stem Cells: Adult Stem Cells
Regeneration: Tissue Renewal
Organism: Mouse
Stage of Development: Embryo

Object Description

The various stages of mouse molar (a) and incisor (b) development, as well as the adult mouse mandible (c), are depicted in sagittal views. WIREs Dev Biol 2012. DOI: 10.1002/wdev.63

Mouse Tooth Development

The study of mouse tooth development allows the identification of the molecular and cellular processes that are important in mammalian tooth development. At embryonic day 11 (placode stage), the oral epithelium (blue) thickens and invaginates into the neural crest-derived mesenchyme (yellow). At the bud stage, mesenchymal cells condense (brown) beneath the epithelial “bud” (blue).  This condensed dental mesenchyme forms most tissues in the tooth including the dentin (c, gray). The enamel (c, pink) is derived from the epithelium.  A central signaling area in the epithelium that regulates tooth shape called the “enamel knot” (a,b, purple) first appears at the cap stage when the epithelial bud begins to surround the dental mesenchyme. At the bell stage, dentin- and enamel-producing cells differentiate and secrete their respective extracellular matrices. The matrix will eventually mineralize, forming the tooth crown. This is followed by tooth eruption (visibility in the mouth).  There are a few differences between developmental events occurring in incisors and molars. In molars (a), secondary enamel knots form at the future site of cusps (elevations on the chewing surface).  During incisor development (b), the vestibular lamina (VL) forms.  This will become the space between the lips and the gums.  Additionally, incisors form the labial and lingual cervical loops (laCL and liCL, respectively).  The cervical loops will house adult epithelial stem cells important for the continuous growth of incisors.  Unlike humans, rodent incisors grow continuously throughout the life of the animal.

References

Jheon, A.H., Seidel, K., Biehs, B., Klein, O.D. From molecules to mastication: the development and evolution of teeth. WIREs Dev Biol, 2012, Published Online: May 03 2012

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