Enamel Tissue #3

Question 1

Which of the 4 mineralized tissue is the only one that does not have an unmineralized formation stage?

Answer 1

Enamel

Question 2

Enamel is the _____ structure to appear in a developing tooth.

Answer 2

2nd, Dentin is first.

Question 3

True or false, Enamel formation is finite.

Answer 3

True

Question 4

True or False, Enamel has enclosed cells.

Answer 4

False

Question 5

What is enamel (composition and structure)?

Answer 5

Biological minerals with apatite crystals oriented in 3D pattern.

Question 6

Is attrition normal or not?

Answer 6

Yes, it is normal wear; abrasion and erosion are not normal.

Question 7

What is the chemical composition of enamel?

Answer 7

Inorganic = 96% by weight
- hydroxyapatite crystals

Organic = 1% by weight
- Types of unique proteins (Amelogenin is main one, 90% of organic material)

Water = 3% by weight
- is the route for ions to travel

Question 8

True or false, Enamel contains lots of collagen fibers.

Answer 8

False, it is the only one of the 4 mineralized tissues that does not contain collagen fibers.

Question 9

Describe the various CEJ relationships….

Answer 9

Most common = cementum overlaps enamel.
Kinda common = cementum meets enamel.
Least common = cementum does not meet enamel.
*These relationships can vary around one tooth and from tooth to tooth.

Question 10

What is microporosity?

Answer 10

A property of enamel that is a pathway for diffusion of small molecules such as water.

Question 11

True or false, enamel needs to be wet in order to prevent deterioration.

Answer 11

True

Question 12

What is a hydration shell?

Answer 12

water that surrounds each crystal in enamel

Question 13

What are the 3 structural components on enamel?

Answer 13

Enamel rods = 5-6 um diameter and 2.5 mm in length

Enamel sheath = outer surface of rods

Interred substance = between the sheaths of the rods

Question 14

What is an Enamel lamella?

Answer 14

*Hypo-mineralized enamel structure = lamellae, extending fro varying depths form the surface of the enamel and consists of longitudinally oriented defects filled with enamel proteins or organic debris (susceptible to caries and stain)

Question 15

What is an Enamel tuft?

Answer 15

*Hypo-mineralized enamel structure = Tuft that projects from DEJ into enamel and contain greater concentration of enamel protein (tuftelin) *contributes to spread of caries at DEJ.

Question 16

What is an Enamel spindle?

Answer 16

*Hypo-mineralized enamel structure = Spindles that extend from the dentin cross the DEJ into the enamel fro a short distance. *Contributes to caress spread in DEJ.