Stellate reticulum

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Stellate reticulum
Cervical-loop.png
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.
Details
LocationDeveloping tooth
Identifiers
Latin reticulum stellatum
Anatomical terminology
Micrograph showing stellate reticulum in an ameloblastoma. H&E stain. Ameloblastoma - very high mag.jpg
Micrograph showing stellate reticulum in an ameloblastoma. H&E stain.

In animal tooth development, the stellate reticulum is a group of cells located in the center of the enamel organ of a developing tooth. These cells are star-shaped (hence stellate) and synthesize glycosaminoglycans. As glycosaminoglycans are produced, water is drawn in between the cells, stretching them apart. As they are moved further away from one another, the stellate reticular cells maintain contact with one another through desmosomes, resulting in their unique appearance. The stellate reticulum is lost after the first layer of enamel is laid down. This brings cells in the inner enamel epithelium closer to blood vessels at the periphery.

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<span class="mw-page-title-main">Human tooth</span> Calcified whitish structure in humans mouths used to break down food

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<span class="mw-page-title-main">Cementum</span> Specialized calcified substance covering the root of a tooth

Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.

<span class="mw-page-title-main">Tooth enamel</span> Major tissue that makes up part of the tooth in humans and many animals

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<span class="mw-page-title-main">Ameloblast</span> Cells which deposit enamel during tooth development

Ameloblasts are cells present only during tooth development that deposit tooth enamel, which is the hard outermost layer of the tooth forming the surface of the crown.

Tomes's processes are a histologic landmark identified on an ameloblast, cells involved in the production of tooth enamel. During the synthesis of enamel, the ameloblast moves away from the enamel, forming a projection surrounded by the developing enamel. Tomes's processes are those projections and give the ameloblast a "picket-fence" appearance under a microscope.

<span class="mw-page-title-main">Enamel organ</span> Aggregate of cells involved in tooth development

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<span class="mw-page-title-main">Human tooth development</span> Process by which teeth form

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Amelogenesis is the formation of enamel on teeth and begins when the crown is forming during the advanced bell stage of tooth development after dentinogenesis forms a first layer of dentin. Dentin must be present for enamel to be formed. Ameloblasts must also be present for dentinogenesis to continue.

<span class="mw-page-title-main">Dental papilla</span>

In embryology and prenatal development, the dental papilla is a condensation of ectomesenchymal cells called odontoblasts, seen in histologic sections of a developing tooth. It lies below a cellular aggregation known as the enamel organ. The dental papilla appears after 8–10 weeks of intra uteral life. The dental papilla gives rise to the dentin and pulp of a tooth.

<span class="mw-page-title-main">Odontoblast</span> Type of cell that produces dentin in teeth

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<span class="mw-page-title-main">Outer enamel epithelium</span>

The outer enamel epithelium, also known as the external enamel epithelium, is a layer of cuboidal cells located on the periphery of the enamel organ in a developing tooth. This layer is first seen during the bell stage.

<span class="mw-page-title-main">Inner enamel epithelium</span> Precursor cells to ameloblasts in tooth development

In animal tooth development, the inner enamel epithelium, also known as the internal enamel epithelium, is a layer of columnar cells located on the rim nearest the dental papilla of the enamel organ in a developing tooth. This layer is first seen during the cap stage, in which these inner enamel epithelium cells are pre-ameloblast cells. These will differentiate into ameloblasts which are responsible for secretion of enamel during tooth development.

<span class="mw-page-title-main">Cervical loop</span> Part of enamel on developing tooth

The cervical loop is the location on an enamel organ in a developing tooth where the outer enamel epithelium and the inner enamel epithelium join. The cervical loop is a histologic term indicating a specific epithelial structure at the apical side of the tooth germ, consisting of loosely aggregated stellate reticulum in the center surrounded by stratum intermedium. These tissues are enveloped by a basal layer of epithelium known on the outside of the tooth as outer enamel epithelium and on the inside as 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 (HERS). At this point it is usually referred to as HERS instead of the cervical loop to indicate the structural difference.

The stratum intermedium in a developing tooth is a layer of two or three cells between the inner enamel epithelium and the newly forming cells of the stellate reticulum. It first appears during the early bell stage of tooth development, at around the 14th week of intrauterine life. These cells are closely attached by desmosomes and gap junctions .The stratum intermedium has a notably high alkaline phosphatase activity. This layer, along with the inner enamel epithelium, is responsible for the tooth enamel formation. It is a part of the dental (enamel) organ. Stratum intermedium stores glycogen. It is absent in the part of the tooth germ that outlines the root portions of the tooth which does not form enamel.

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<span class="mw-page-title-main">Dentigerous cyst</span> Medical condition

A dentigerous cyst, also known as a follicular cyst, is an epithelial-lined developmental cyst formed by accumulation of fluid between the reduced enamel epithelium and the crown of an unerupted tooth. It is formed when there is an alteration in the reduced enamel epithelium and encloses the crown of an unerupted tooth at the cemento-enamel junction. Fluid is accumulated between reduced enamel epithelium and the crown of an unerupted tooth.

<span class="mw-page-title-main">Ameloblastic fibroma</span> Medical condition

An ameloblastic fibroma is a fibroma of the ameloblastic tissue, that is, an odontogenic tumor arising from the enamel organ or dental lamina. It may be either truly neoplastic or merely hamartomatous. In neoplastic cases, it may be labeled an ameloblastic fibrosarcoma in accord with the terminological distinction that reserves the word fibroma for benign tumors and assigns the word fibrosarcoma to malignant ones. It is more common in the first and second decades of life, when odontogenesis is ongoing, than in later decades. In 50% of cases an unerupted tooth is involved.

Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. Tooth formation begins before birth, and the teeth's eventual morphology is dictated during this time. Dental anatomy is also a taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment.

In dental anatomy, the junctional epithelium (JE) is that epithelium which lies at, and in health also defines, the base of the gingival sulcus. The probing depth of the gingival sulcus is measured by a calibrated periodontal probe. In a healthy-case scenario, the probe is gently inserted, slides by the sulcular epithelium (SE), and is stopped by the epithelial attachment (EA). However, the probing depth of the gingival sulcus may be considerably different from the true histological gingival sulcus depth.

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