Unit - 10 Enamel

Question 1

What are the chemical properties of enamel?

Answer 1

96% inorganic
1% organic
3% water

Question 2

Is enamel vascular or non-vascular?

Answer 2

Non-vascular

Question 3

How permeable is enamel?

Answer 3

Semi-permeable

Question 4

How thick is enamel?

Answer 4

Approximately 2.5mm coming to a feather edge at the CEJ

Question 5

How does enamel appear on radiographs?

Answer 5

Radiopaque

Question 6

What functions does enamel provide surface for?

Answer 6

Mastication and speech

Question 7

How many pounds of pressure per tooth can enamel stand?

Answer 7

20-30 pounds of pressure

Question 8

Enamel clinical considerations

Answer 8

Attrition
Abfraction
Abrasion
Erosion
Caries

Question 9

Enamel matrix is an ectodermal product because

Answer 9

Ameloblasts are derived from the inner enamel epithelium of the enamel organ, which was originally derived from the ectoderm of the embryo.

Question 10

Does enamel contain collagen protein?

Answer 10

No

Question 11

What unique classes of protein does enamel contain?

Answer 11

Amelogenins
Ameloblastin
Enamelins

Question 12

Amelogenesis is the process of enamel formation that occurs during what stage of tooth development?

Answer 12

Apposition

Question 13

What produces enamel during apposition?

Answer 13

Ameloblasts

Question 14

What do ameloblasts actively pump into forming enamel matrix as it is being secreted by each of the Tomes processes?

Answer 14

Calcium hydroxyappetite

Question 15

What intiates the development of the Tomes processes?

Answer 15

The movement of ameloblasts as it retreats from the first layer it deposited.

Question 16

What is responsible for forming the prism shape found in enamel structure?

Answer 16

Tomes process

Question 17

The Tomes process remains at the matrix producing end of the ameloblasts throughout the matrix production phase until

Answer 17

Just before the last layer of matrix is to be laid

Question 18

The first and last layer of enamel is

Answer 18

Prsimless

Question 19

Where is the first wave of enamel matrix located?

Answer 19

At the incisal or occlusal surfaces near the DEJ

Question 20

Where is the second wave of enamel matrix located?

Answer 20

Overlaps the first with the entire process moving cervically to the CEJ

Question 21

What are the clinical considerations during enamel formation?

Answer 21

Developmental disturbances
Pit and groove patterns

Question 22

What happens to the hydroxyappetite crystals during the maturation phase of enamel development?

Answer 22

They grow and coalesce with each other

Question 23

The remnant matrix must now be _______ to allow full mineralization to occur

Answer 23

Removed

Question 24

The ameloblasts will now take on a new function, a cell capable of

Answer 24

“Digestion” removing the matrix remnants and water.

Question 25

The crystals continue to grow until

Answer 25

Enamel is 96% mineral content

Question 26

Does enamel mineralization continue after the eruption of the tooth?

Answer 26

Yes

Question 27

The post-eruption maturation is due to

Answer 27

The deposition of minerals, such as fluoride and calcium, from saliva into hypomineralized areas of enamel

Question 28

The last product the ameloblasts spews out is called the

Answer 28

Enamel Cuticle or Nasmyth’s Membrane

Question 29

Each ameloblasts forms the body of one rod, and at least three more adjacent ameloblasts continue to the interrod enamel that makes up the

Answer 29

“Tails” of the “keyholes”

Question 30

An optical phenomenon visualised when a cut or fractured enamel surface is viewed under reflected light. These bands demonstrate the synchronous decussation of individual or groups of enamel prisms

Answer 30

Hunter-Shregar Bands

Question 31

What happens to the enamel during whitening?

Answer 31

A chemical reaction carrying out an oxydizing reaction in the enamel and dentin.

Question 32

Basic structural component of enamel

Answer 32

Interrod enamel

Question 33

Incremental growth lines or bands as seen in enamel

Answer 33

Incremental Lines of Retzius

Question 34

Where the margin of each enamel layer reaches the free surface of the enamel, a fine ridge is seen in recently erupted teeth

Answer 34

Imbrication Lines or Perikymata

Question 35

The transition from an intra to an extra-uterine environment leaves its mark in deciduous teeth and first molars as an accentuated enamel incremental ring called

Answer 35

Neonatal lines

Question 36

Short, linear defects found at the DEJ and extend into the enamel often being more prevalent at the cusp tips

Answer 36

Enamel spindles

Question 37

Closed cracks or defects which, in their manner of propagating, act to prevent enamel fractures

Answer 37

Enamel tufts

Question 38

Fissure-like defects that extend along the longitudinal axis of the tooth down to the dentin layer

Answer 38

Enamel lamella