Enamel ch. 12 (Questions)

What is the properties of enamel?

96% inorganic
3% water
1% organic

What is the primary property of enamel?


What is the secondary properties of enamel?

Carbonate, sodium, magnesium, potassium, and fluoride

Crystals are _______ bigger than those in dentin.


How thick is the enamel?

0-2.6 mm

Enamel is ____ at the cervical region and _____ at the incisal/occlusal region.



tooth to tooth contact


Mechanical contact


chemical means


tooth to tooth contact, cervical region



When does the enamel matrix form?

During the secretory phase of apposition stage

What cells are involved in the formation of the enamel matrix?

Ameloblasts / columnar cells that differentiate

Ameloblasts are dervived from the ___________ of the ______.

Inner enamel epithelium
Enamel Organ

IEE differentiates> ________>__________>________

1. Preameloblasts contact dentin
2. Ameloblasts secrete enamel matrix
3. Enamel

Enamel matrix is secreted between _______ to form molds called ________.

Tomes processes

Tomes process of each ameloblast secretes _________ into molds to create ________.

Enamel matrix

What are the components of the initial enamel matrix?

- partially mineralized
- proteins
- carbohydrates
- small amount of CA10(PO4)6(OH)2

What is the composition of mature enamel?

- 96% inorganic
-3% water
- 1% organic
- No collagen proteins
- Proteins- amelogenins, ameloblastins, enamelins

How many tomes processes are there for each ameloblasts?

1 to 1

Enamel appostition happens in ________ waves. What happens in these waves

1. Formed in the incisal/occlusal portion of the future crown near the DEJ
2. Overlaps the first wave

During maturation ameloblasts remove _______ and deposits ______?

1. water
2, Hydroxyapatite

Ameloblasts become ______ and fuse with __________.

Oral mucosa

After ameloblasts create
__________ pathway, they are _____.

1. Eruption
2. lost

What are three ways to receive systemic flouride?

Drops, water, tablets

Systemic flouride enters what during development?

Crystaline formation

What is the difference between topical and systemic fluoride in terms of caries?

Systemic makes teeth more caries resistant while topical reverses caries process

What are ways to receive topical flouride?

- water
- professional application
- RX/OTC gels
- rinses
- foams
- toothpastes

What are two types of enamel dysplasia in those with fluorosis?

1. Enamel Hypoplasia: pitting
2. Enamel hypcacification: intrinsic staining

How thick and long are enamel rods?

4um thick and 2.5 mm long

________--> mature --> _______
Fill in with the relation to enamel rods

1. Hexagon
2. Irregular and flattened

Enamel rods are __________ to the dentin and DEJ.


The crystals within these rods bend left and right in order to increase the enamel strength?

Hunter-Schreger Bands

Hunter-Schreger Bands can only be seen with ________ light.


These rods interdigitate at the cusp and are more commonly seen in posterior teeth.

Gnarled Enamel

Gnarled Enamel reduces ___________.

Enamel stress

Gnarled enamel appears as ______________.

Stacked wavy lattice

These rods surrond enamel, have a divergent crystalline orientation, and fracture easily.

Interrod enamel

The DEJ is ________ towards the enamel and __________towards the dentin.


The DEJ is more pronounced in the __________ region.


Retzius are ___________ depositions of enamel and _____________ the enamel rods.


These are usually on non-masticatory surface and lost to wear.

Imbrication lines & perikymata

These mark truama of ameloblasts during birth.

Neonatal lines

What is not a secondary component of enamel?
A. Potassium
B. fluoride
C. water
D. magnesium

C. Water

The crystals in enamel are ____ larger than dentin.
A. 20%
B. 10%
C. 40%
D. 30%

D. 30%

Which causes the wearing down of enamel due to tooth to tooth contact?
A. Attrition
B. Abrasion
C. Abfraction
D. A & C
E. A& B
F. All of the above

D. Attrition and Abfraction

What is the Ameloblasts derived from?
C. Ectoderm
D. Dental sac


Put the following in order.
A. Ameoblasts secrete enamel matrix
B. enamel
C. IEE differentiates
D. Preameloblasts contact dentin


What is the ratio of tomes processes to ameloblasts?
A. 1:1
B. 2:1
C. 1:2
D. 1:3

A. 1:1

Which is NOT a component of the initial enamel matrix?
A. Carbohydrates
B. collagen proteins
C. Hydroxyapatite
D. All are compements

B. Collagen Proteins

Which is a protein in mature enamel?
A. Ameogenins
B. Ameloblastins
C. Enamelins
D. A & C
E. B & C
F. All of the above

F. All of the above

T/F Enamel apposition begins at the incisal/occlusial portion of the crown near the DEJ.


What is deposited in the enamel after water is removed?
A. Carbon
B. hydroxyapatite
C. magnesium
D. F12

B. hydroxyapatite

T/F Systemic Fuoride reverses the caries process

It makes teeth more resistant to caries.

Which is not a way to deliver fluoride systemically?
A. Drops
B. gummies
C. tablets
D. water

B. Gummies

T/F Topical Fluoride enters the crystalline formation during development.

False. Systemic does

T/F Immature rods are usually a irregular hexagonal shape


What light is used to view Hunter-Schregers Bands?
D. Translucent


What lines bend to the left and right to increase the enamels strength?
A. Gnarled
B. Retzius
C. Hunter-Schregers
D. Enamel spindles

C. Hunter-Schregers

Which of the following have no clinical importance?
A. Enamel Lamellae
B. Retzius
C. Enamel spindles
D. Enamel tuffs
E. three of the above
F. All of the above

E. Enamel tuff and Enamel Lamellae

Which runs transverse to the enamel rods?
A. Enamel Lamellae
B. Lines of Retzius
C. Imbrication lines
D. Hunter-Schregers

B. Lines of Retzius

Which are commonly found on the canince, first premolars, and maxillary centrals?
A. Gnarled enamel
B. Enamel spindles
C. Lines of Retzius
D. Perikymata

D. Perikymata

WhIch appears in stacked wavy lattice?
A. Gnarled Enamel
B.Enamel lamallae
C. Enamel spindles
D. Perikymata

A. Gnarled Enamel

Which appears like small dark brushes near the DEJ that are less mineralized areas?
A. Enamel Lamellae
B. Enamel Tufts
C. Enamel Spindles
D. Neonatal lines

B. Enamel Tufts

Which are partially mineralized vertical sheets that form from the DEJ to the outer enamel surface?
A. Enamel Tufts
B. Imbrication Lines
C. Enamel lamellae
D. Line of Retzius

C. Enamel lamellae

Which is responsible reducing occlusal stress?
A. Imbrication Lines
B. neonatal lines
C. Line Retzius
D. Gnarled enamel

D. Gnarled enamel

Which marks trauma of ameloblasts during birth?
A. enamel tufts
B. line of retzius
C. enamel spindles
D. Neonatal lines

D. Neonatal lines

Which is from the result of the odontoblasts crossing the BM before mineralization?
A. enamel lamallae
B. Enamel spindles
C. enamel tufts
D. neonatal lines

B. Enamel spindles