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Flashcards in Enamel Tissue Deck (52)
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1

T/F - Enamel is the hardest of the 4 mineralized tissues of the body

True

2

T/F - All 4 mineralized tissues of the body are connective tissue

False - Enamel is NOT a connective tissue

3

T/F - All mineralized tissues have a partially mineralized (immature) stage, and a fully mineralized (mature) stage

False - Enamel is the only mineralized tissue that goes through an immature stage....the other 3 go from unmineralized to mineralized (never partially mineralized)

4

T/F - Enamel formation is finite

True - Ameloblasts complete its enamel formative cycle once the thickness of enamel is reached at a site

5

What is the first appearing mineralized tissue in a developing tooth? What is second?

Dentin is first
Enamel is second

6

What is lacking in enamel?

Enclosed cells (acellular)
Nerves (aneural)
Blood vessels (avascular)
Lymph vessels (alymphatic)

7

What tissue in a tooth contains enclosed cells, nerves, blood vessels, and lymph vessels?

Pulp

8

Enamel definition

A composite biological mineral with apatite crystals oriented in a complex, three-dimensional pattern

9

Hardness of enamel

5 on Moh's scale - comparable to mild steel
Can withstand both shearing and impact forces well
Brittle without dentin support

10

Enamel translucency

Hue depends on location, surface condition of enamel, attraction to stain substances, and age changes

11

What is required for enamel to maintain its integrity?

A wet environement

12

Attrition

Normal, slow wearing of tooth substances under the stress of mastication

13

Abrasion

Abnormal wearing of tooth substance from extraoral substances (toothpick)

14

Erosion

Abnormal wearing of tooth substances from acid

15

Microporosity of enamel

The pathway for diffusion of small molecules such as water
Electrochemical effects on pore walls lead to carious lesions

16

Remineralization of enamel

Mineral is returned to the molecular structure of enamel by the way of saliva
When demineralization exceeds remineralization, cavitation occurs

17

Inorganic substances of enamel

96% of enamel by weight
Hydroxyapatite crystals - principle component is calcium hydroxyapatite

18

How do enamel crystals compare to other mineralized tissues?

Enamel crystals are larger and consist of more impurities (fluoride, carbide)

19

Organic substances of enamel

1% by weight

20

What are the types of proteins unique to enamel?

Amelogenin and non-amelogenin

21

What are some non-amelogenin proteins

Enamelin
Amelin
Tuftelin

22

What is the most prominent organic substance of enamel?

Amelogenin - a seed protein for normal mineralization

23

Enamel protein arrangement

Arranged in a lace-like patern throughout the volume of enamel and clsoesly associated with the surface of the crystals

24

Enamel is the only mineralized tissue that does not contain what?

Collagen fibers

25

Water in enamel

3% of weight
Distributed throughout the volume of enamel by the way of micropores between crystals and proteins
Most of the water forms a hydration shell around the crystals

26

What is the clinical importance of water to the enamel?

-Provides a route for fluoride ions, calcum, and phosphorous ions for remineralization
-Provides distribution for whitening substances, artificial, and natural substances
-Provides distribution for acidophilic microorganisms, age changes, etc

27

Age changes to enamel

Enamel wears slowly (attrition)
Color darkens
Composition of surface changes
Fluoride increases at the surface
Porosity is reduced
Less susceptible to caries
Subject to changes due to systemic age changes

28

What are the different CEJ relationships?

Cementum overlaps enamel (most common)
Cementum meets enamel
Cementum does not meet enamel (least common)

29

What is the clinical significance of CEJ relationship?

The CEJ relationships vary around the tooth and form tooth to tooth

30

DEJ configuration at the coronal area

Scalloped to help adapt to withstand occlusal forces