# Cervical loop

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{{Short description|Part of enamel on developing tooth}}
{{Use dmy dates|date=April 2024}}
{{No footnotes|date=December 2010}}
thumbnail|The cervical loop area: (1) dental follicle cells, (2) dental mesenchyme, (3) Odontoblasts, (4) Dentin, (5) stellate reticulum, (6) outer enamel epithelium, (7)inner enamel epithelium, (8) ameloblasts, (9) enamel.

The '''cervical loop''' is the location on an [enamel organ](/source/enamel_organ) in a [developing](/source/Animal_tooth_development) [tooth](/source/tooth) where the [outer enamel epithelium](/source/outer_enamel_epithelium) and the [inner enamel epithelium](/source/inner_enamel_epithelium) join. The cervical loop is a [histologic](/source/histology) term indicating a specific epithelial structure at the apical side of the tooth germ, consisting of loosely aggregated [stellate reticulum](/source/stellate_reticulum) in the center surrounded by [stratum intermedium](/source/stratum_intermedium). These tissues are enveloped by a basal layer of epithelium known on the outside of the tooth as [outer enamel epithelium](/source/outer_enamel_epithelium) and on the inside as [inner enamel epithelium](/source/inner_enamel_epithelium). During root formation the inner layers of epithelium disappear and only the basal layers are left creating [Hertwig's epithelial root sheath](/source/Hertwig's_epithelial_root_sheath) (HERS). At this point it is usually referred to as HERS instead of the cervical loop to indicate the structural difference.

==Cervical loop as epithelial stem cell niche==
It is thought that the central epithelial tissue of the cervical loop, the [stellate reticulum](/source/stellate_reticulum), acts as a [stem cell](/source/stem_cell) reservoir. In continuously growing teeth such as the rodent incisor the original structure of the cervical loop is maintained and no HERS forms. The stem cells provide the epithelial progeny to sustain the continuous growth.

==References==
{{Reflist}}

===General references===
*Cate, A.R. Ten. Oral Histology: development, structure, and function. 5th ed. 1998. {{ISBN|0-8151-2952-1}}.
*Ross, Michael H., Gordon I. Kaye, and Wojciech Pawlina. Histology: a text and atlas. 4th edition. 2003. {{ISBN|0-683-30242-6}}.
*Harada, H., Kettunen, P., Jung, H. S., Mustonen, T., Wang, Y. A., and Thesleff, I. (1999) Localization of putative stem cells in dental epithelium and their association with Notch and FGF signaling. J. Cell Biol. 147: 105–120

{{Tooth development}}

Category:Tooth development

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Adapted from the Wikipedia article [Cervical loop](https://en.wikipedia.org/wiki/Cervical_loop) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Cervical_loop?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.