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315:- as long as the ameloblasts are in contact with the dental papilla, they receive nutrient material from the blood vessels of the tissue, but due to formation of this dentin the original source of nutrition is cut off and the ameloblasts are supplied by capillaries penetrating the outer enamel epithelium. This change in nutrition source is referred to as "reversal of nutrition".
331:
After the formation of enamel matrix, mineralisation of enamel takes place which is known as maturation. During this stage, the ameloblasts are slightly reduced in length. The stratum intermedium cells lose their cuboidal shape and assumed to be as spindle shape. During this stage, ameloblasts also
375:
which will later mineralize to form enamel, the hardest substance in the human body. Ameloblasts control ionic and organic compositions of enamel. It is theorized that a circadian clock (24-hour) probably regulates enamel production on a daily cycle by the ameloblasts (similar to osteoblasts in
388:
found in the primary teeth and in the larger cusps of the permanent first molars, showing a disruption in enamel production when the person is born. High fevers in childhood are also an example of bodily stressors causing interruptions in enamel production.
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In this morphogenic stage, the morphology of the cells are short, columnar with large oval nuclei. The golgi apparatus and centrioles are located in the proximal end of the ameloblasts, and mitochondria are dispersed throughout the cytoplasm.
340:
In this stage, enamel is completely developed and fully calcified. Now the cell layers form a stratified epithelial covering of enamel, which is known as reduced enamel epithelium. This reduced enamel epithelium protects the mature enamel.
194:. Initially the preameloblasts will differentiate into presecretory ameloblasts and then into secretory ameloblasts which lay down the tooth enamel. The differentiation from preameloblasts to ameloblasts occurs during the first stage of
161:
Each ameloblast is a columnar cell approximately 4 micrometers in diameter, 40 micrometers in length and is hexagonal in cross section. The secretory end of the ameloblast ends in a six-sided pyramid-like projection known as the
300:
In this stage, the ameloblast cells become longer and the nucleus migrates towards the proximal end. In contrast to this, the Golgi apparatus and centrioles migrate towards the distal end. This change is referred to as
56:
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)
580:
Takahashi S, Kawashima N, Sakamoto K, Nakata A, Kameda T, Sugiyama T, Katsube K, Suda H (February 2007). "Differentiation of an ameloblast-lineage cell line (ALC) is induced by Sonic hedgehog signaling".
349:
In this stage, the reduced enamel epithelium proliferates and induce atrophy. The reduced enamel epithelium releases enzymes which destroy the connective tissue, in a process known as desmolysis.
396:
after childhood exposure (between the ages of 2 and 8 years old) to excess consumption of fluoride, an elemental agent used to increase enamel hardness and as a result, prevent dental caries.
228:
inhibitor, is over expressed in the epithelium of developing teeth, the ameloblasts do not differentiate and no enamel forms. Another example includes the conditional deletion of
52:
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There are various factors which can affect the differentiation and development of ameloblasts, causing abnormalities to form within the tooth structure. One example is the
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production of bone tissue). Ameloblasts adjust their secretory and resorptive activities to maintain favorable conditions for biomineralization.
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In this stage, formation of enamel matrix begins. During the formation of enamel matrix, the ameloblasts retain approximately the same length.
170:, the basic unit of tooth enamel. Distal terminal bars are junctional complexes that separate the Tomes' processes from ameloblast proper.
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in the epithelium of developing teeth, which may cause impaired differentiation of ameloblasts resulting in deficient enamel formation.
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origin. Their differentiation from preameloblasts (whose origin is from inner enamel epithelium) is a result of signaling from the
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These cells are sensitive to their environment. One common example is illustrated by the neonatal line, a pronounced incremental
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The ameloblasts will only become fully functional after the first layer of dentin (predentin) has been formed by
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Another possible example of this sensitivity (stress response pathway activation) may be the development of
205:. The cells are part of the reduced enamel epithelium after enamel maturation and then subsequently undergo
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Illustrated Dental
Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 151
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220:(bone morphogenetic protein,) which has an important role in ameloblast differentiation. When
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711:"Stress response pathways in ameloblasts: implications for amelogenesis and dental fluorosis"
467:"Ameloblast differentiation in the human developing tooth: effects of extracellular matrices"
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Simmer JP, Papagerakis P, Smith CE, Fisher DC, Rountrey AN, Zheng L, Hu JC (October 2010).
8:
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Sehic A, Nirvani M, Risnes S (October 2013). "Incremental lines in mouse molar enamel".
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He P, Zhang Y, Kim SO, Radlanski RJ, Butcher K, Schneider RA, DenBesten PK (June 2010).
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before or after tooth eruption. These stages occur during the third and final stage of
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166:. The angulation of the Tomes' process is significant in the orientation of
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618:"Localization and quantitative co-localization of enamelin with amelogenin"
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Ten Cate's oral histology : development, structure, and function
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307:. During this stage, the odontoblasts start laying down dentin.
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Gallon V, Chen L, Yang X, Moradian-Oldak J (August 2013).
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Stem cells in craniofacial development and regeneration
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The life cycle of ameloblasts consists of six stages:
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List of human cell types derived from the germ layers
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List of distinct cell types in the adult human body
145:present only during tooth development that deposit
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Cells which deposit enamel during tooth development
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198:, called the pre-secretory (or inductive) phase.
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767:"Regulation of dental enamel shape and hardness"
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969:Non-terminally differentiated (blast) cells
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709:Sierant ML, Bartlett JD (September 2012).
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521:. Hoboken, New Jersey: Wiley-Blackwell.
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122:Anatomical terms of microanatomy
213:, called the maturation phase.
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622:Journal of Structural Biology
517:Huang GT, Thesleff I (2013).
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250:Formative (secretory) stage (
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283:is of ameloblastic origin.
279:ALC (ameloblast like cell)
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559:(Eighth ed.). Mosby.
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416:Amelogenesis imperfecta
911:Epithelial root sheath
304:"reversal of polarity"
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380:Clinical significance
312:Reversal of nutrition
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728:10.3390/cells1030631
287:1. Morphogenic stage
946:Stratum intermedium
345:6. Desmolytic stage
336:5. Protective stage
327:4. Maturative stage
296:2. Organizing stage
941:Stellate reticulum
361:which secrete the
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263:Desmolytic stage
257:Maturative stages
244:Morphogenic stage
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222:follistatin
174:Development
168:enamel rods
139:Ameloblasts
68:Identifiers
18:Ameloblasts
963:Categories
859:Ameloblast
452:References
373:amelogenin
236:Life cycle
184:ectodermal
182:tissue of
180:epithelium
33:Ameloblast
880:Dentition
537:809365748
281:cell line
207:apoptosis
157:Structure
885:Teething
801:20675598
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400:See also
369:enamelin
366:proteins
353:Function
873:General
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254:appear)
230:dicer-1
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63:Details
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