Enamel II TEST #2 2/14/17 Colombo

Question 1

T/F Enamel formation is simultaneous throughout the tooth.

Answer 1

False

They are no simultaneous

Question 2

What are three enamel deposition proteins?

Answer 2

• Ameloginins
• Ameloblastin
• Enameliln

Question 3

What is an enamel protein that deals with the organic component degradation?

Answer 3

• Enamelysin

- enamel matrix sering protease

Question 4

What is an enamel protein that deals with the basal lamina during maturation?

Answer 4

-Amelotin

Question 5

What is the main protein family in developing enamel (89-90%)?

Answer 5

-Amelogenins

Question 6

When are amelogenins expressed?

Answer 6

-Only while enamel is being produced (stops during maturation)

Question 7

What enamel protein restricts the lateral Hydroxyapatitie growth?

Answer 7

-Amelogenins

Question 8

T/F If you have no amelogenins you will have no enamel rods

Answer 8

True

Question 9

What enamel protein is about 10% of the enamel organic content?

Answer 9

-Ameloblastin

Question 10

When is ameloblastin expressed?

Answer 10

-All the way through maturation

Question 11

What is the least abundant enamel protein?

Answer 11

-Enamelin

Question 12

If you lose enamel what occurs?

Answer 12

-You get no enamel

Question 13

T/F If you lose ameloblastins the ameloblasts “fall off” leading to no enamel

Answer 13

True

Question 14

What is an enamel protein that is MMP?

Answer 14

-Enamelysin

Question 15

When do you find enamelysin?

Answer 15

-During enamel deposition

Question 16

What does enamelysin chop up?

Answer 16

• Ameloblastin

- Enamelin

Question 17

If you lose enamelysin what occurs?

Answer 17

-You get thin immature enamel

Question 18

What degrades Amelogenins?

Answer 18

-Enamel Matrix serine protease

Question 19

What occurs if you lose Enamel Matrix serine proteases?

Answer 19

-Immature enamel

Question 20

What are three reasons to do enamel acid etching?

Answer 20

• Fissure sealants
• Bonding restorative materials to enamel
• Cementing orthodontic materials to enamel

Question 21

T/F Acid etching provides better bonding surfaces

Answer 21

True

Question 22

How is acid etching accomplished?

Answer 22

-Dissolving enamel crystals

Question 23

What is the most common type of acid etching?

Answer 23

-Type I

Question 24

What does type I enamel etch?

Answer 24

-Removal of enamel rods

Question 25

What does type II enamel etch?

Answer 25

-Interrod enamel romoved

Question 26

What does type III enamel etch?

Answer 26

-Both interrod and enamel rod removal (irregular and indiscriminate pattern)

Question 27

What is erosion?

Answer 27

-Removal of enamel by break down of crystals

Question 28

What causes abfraction?

Answer 28

-Stresses placed on the tooth on the rod-interrod enamel causing the rods to separate

Question 29

What are two reasons that enamel appears darker in older individuals?

Answer 29

- Staining | - Thinning of enamel

Question 30

What happens with the water content as enamel ages?

Answer 30

-The water content decreases

Question 31

T/F Enamel becomes less porous over time

Answer 31

TRUE

Question 32

What are two periodic features of enamel structure?

Answer 32

- Striae of Retzius / Perikymata | - Cross Striations

Question 33

What are two optical features of enamel structure?

Answer 33

- Hunter-Schreger Bands | - Gnarled Enamel

Question 34

What are three histological features of enamel structure?

Answer 34

- Enamel Tufts - Enamel Lamellae - Enamel Spindles

Question 35

What appears as longitudinal lines or stripes on ground section (non demineralized) running from the DEJ to the enamel surface?

Answer 35

-Striae of Retzius

Question 36

What do accentuated striae such as the neonatal line indicate?

Answer 36

-Significant physiological disturbances

Question 37

What is the most accentuated stria of Retzius?

Answer 37

-Neonatal Line (reflects changes at birth)

Question 38

T/F The Neonatal line is found in all primary teeth

Answer 38

True

Question 39

What are surface manifestation of Stiae of Retzius?

Answer 39

-Perikymata

Question 40

What do the Cross striations show?

Answer 40

-Enamel growth rate at 4 microns per day

Question 41

What is an optical phenomenon due to differential light scattering when adjacent groups of rods alternate direction?

Answer 41

-Bands of Hunter-Schreger

Question 42

What do bands of Hunter-Schreger appear as?

Answer 42

-Alternating light and dark bands

Question 43

What is a complex twisting of rods as they proceed vertically away from the DEJ?

Answer 43

-Gnarled Enamel

Question 44

T/F Enamel tufts contain more enamel proteins and are hypocalcified

Answer 44

True

Question 45

What do the enamel lamellae function to do?

Answer 45

-Give the enamel more structural support to resist fracture

Question 46

What is the difference between lamellae and tufts?

Answer 46

-Lamellae run all the way through the enamel and tufts only run part way through

Question 47

What do enamel spindles result from?

Answer 47

-Odontoblastic processes that traverse the DEJ and penetrate the enamel

Question 48

Where do you often see enamel spindles?

Answer 48

- Cusp tips | - Incisal tip

Question 49

T/F Enamel spindles are enamel

Answer 49

False | -They have trace amounts of dentin

Question 50

What is the Developmental problems with tooth development/enamel formation known as?

Answer 50

-Genetic dysplasia

Question 51

What does tetracycline staining look like?

Answer 51

-Brown, yellow or gray band of pigmentation

Question 52

T/F Excess fluoride interferes with amelogenesis

Answer 52

True

Question 53

What type of mineralized enamel do you get if you take to much fluoride?

Answer 53

-Hypermineralized