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Difference between revisions of "Dental enamel"

(Created page with "With a brinell hardness of 300- 350 HB, enamel is the hardest substance the human body can produce. It covers the crown and can differ in its thickness from up to 2 mm, at the...")
 
 
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With a brinell hardness of 300- 350 HB, enamel is the hardest substance the human body can produce. It covers the crown and can differ in its thickness from up to 2 mm, at the cusps of the crown, phasing out to the cervical area. At Fissures the thickness can go down to 0,1mm.
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''Synonym: Substantia adamantina, Enamelum''<br />
With a brinell hardness of 300- 350 HB, enamel is the hardest substance the human body can produce. It covers the crown and can differ in its thickness from up to 2 mm, at the cusps of the crown, phasing out to the cervical area. At Fissures the thickness can go down to 0,1mm.
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'''''German''': [[:de:Zahnschmelz|Zahnschmelz]]''<br />
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[[de:Zahnschmelz]]
  
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==Definition==
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With a brinell hardness of 300- 350 HB, the '''dental enamel''' is the hardest substance the human body can produce. It covers the crown and can differ in its thickness from up to 2 mm at the cusps of the crown, down to 0,1 mm at fissures and is phasing out to the cervical area.
  
'''1. Chemical structure:'''
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==Chemical structure==
  
* 1.1 Anorganic substances (Apatite) 95 – 98 (wt%)
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*Anorganic substances (Apatite) 95 – 98 (wt%)
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**Hydroxyapatite [Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH]
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**Fluorapatite [Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>F]
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**Carbonapatite [Ca<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>CO<sub>3</sub>]
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*Organic matrix (amelogenin, enamelin) 1-2 (wt%)
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*Water 3-4 (wt%)
  
Hydroxyapatite [Ca5 (PO4)3 OH]
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==Crystalline structure==
  
Fluorapatite [Ca5 (PO4)3 F]
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The dental enamle consists of enamel-prisms with a diameter of 4-5 mycrometers (built up out of ca. 1000 apapite-crystals), growing in size from the enamel-dentin-boarder towards the surface. Between the prisms, there is interprismatic enamel.
Carbonapatite [Ca10 (PO4)6 CO3]
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The last 30-80 mycrometers of the enamel surface are free from prisms.
  
* 1.2 Organic matrix (amelogenin, enamelin) 1-2 (wt%)
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==Hunter-Schreger-stripes==
  
* 1.3 Water 3-4 (wt%)
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The prisms grow vertical to the enamel-dentin-boarder and make their way to the surface as bundles. This is the reason for the so called Hunter-Schreger-stripes. Bright and dark stripes occur because of the different light refraction.
  
'''2. Crystalline structure:'''
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==Retzius-stripes (growth-lines)==
  
The Enamle consists of enamel-prisms with a diameter of 4-5 mycrometers (built up out of ca. 1000 apapite-crystals), growing in size from the enamel-dentin-boarder, towards the surface. Between the prisms, there is interprismatic enamel.
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Parallel to the surface there is a second type of stripes. The so called Retzius-stripes occur because of the periodical calcification of the dental enamel.
The last 30-80 mycrometers of the enamel surface is free from prisms.
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'''3. Hunter-Schreger-stripes:'''
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The dental enamel has no cells included and therefore cannot be regenerated.
 
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The prisms grow vertical to the enamel-dentin-boarder and make their way to the surface as bundles. This is the reason for the so called Hunter-Schreger-stripes. Bright and dark stripes occurring, because of the different light refraction.
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'''4. Retzius-stripes (growth-lines)'''
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Parallel to the surface there is a second type of stripes. The so called Retzius-stripes occur, because of the periodical calcification of the enamel.
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Enamel has no cells included and therefore cannot be regenerated.
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Latest revision as of 14:16, 3 June 2016

Synonym: Substantia adamantina, Enamelum
German: Zahnschmelz

1 Definition

With a brinell hardness of 300- 350 HB, the dental enamel is the hardest substance the human body can produce. It covers the crown and can differ in its thickness from up to 2 mm at the cusps of the crown, down to 0,1 mm at fissures and is phasing out to the cervical area.

2 Chemical structure

  • Anorganic substances (Apatite) 95 – 98 (wt%)
    • Hydroxyapatite [Ca5(PO4)3OH]
    • Fluorapatite [Ca5(PO4)3F]
    • Carbonapatite [Ca10(PO4)6CO3]
  • Organic matrix (amelogenin, enamelin) 1-2 (wt%)
  • Water 3-4 (wt%)

3 Crystalline structure

The dental enamle consists of enamel-prisms with a diameter of 4-5 mycrometers (built up out of ca. 1000 apapite-crystals), growing in size from the enamel-dentin-boarder towards the surface. Between the prisms, there is interprismatic enamel. The last 30-80 mycrometers of the enamel surface are free from prisms.

4 Hunter-Schreger-stripes

The prisms grow vertical to the enamel-dentin-boarder and make their way to the surface as bundles. This is the reason for the so called Hunter-Schreger-stripes. Bright and dark stripes occur because of the different light refraction.

5 Retzius-stripes (growth-lines)

Parallel to the surface there is a second type of stripes. The so called Retzius-stripes occur because of the periodical calcification of the dental enamel.

The dental enamel has no cells included and therefore cannot be regenerated.

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