Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Oral Biology II COPY > Enamel > Flashcards

Enamel Flashcards

1
Q

Underlying dentin support is critical for enamel functions because of what property of enamel?

A

Brittleness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 main components of enamel?

A
  • Organic (1-2% enamel proteins, NOT collagen)
  • Water (2-3%)
  • Inorganic hydroxyapatite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Enamel crystals pack closely together to form what two structures?

A

-Enamel rods and interrod enamel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the three main variations of hydroxyapatite?

A
  • Carbonatoapetite (more vulnerable to acid)
  • Magnesium incorporated (more vulnerable to acid)
  • Flourapetite (less vulnerable to acid)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are carbonate and magnesium incorporated enamel more prevalent?

A

Inner enamel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Each enamel crystal is roughly 60-70 nm wide, 25-30 nm thick, very long and what general shape?

A

Hexagonal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In what orientation would you expect to find enamel rods in reference to the DEJ?

A

Perpendicular, or close to it, possibly curving and intertwining as they approach the surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The protein rich areas surrounding enamel rods are called?

A

Rod Sheath

*runs 3/4 of the way around the rod, connecting rod and interrod enamel crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are two examples of enamel rod sheath proteins?

A

1-Ameloblastins

2-Amelogenins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Rather than the keyhole analogy, what is a more accurate way to describe the rod-interrod relationship?

A

Columns embedded in interrod enamel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ameloblasts contribute to what structures in the enamel?

A

An enamel rod and the surrounding interrod enamel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

As enamel matures organic component ________ and mineralization ________

A

decreases, increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 3 general phases of ameloblast maturation?

A

1-Pre-secretory
2-Secretory
3-Maturation (reduction of organic matrix, increase mineralization)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The youngest ameloblasts are found where on the tooth?

A

Cervical portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What binds ameloblasts together to keep them moving in sync?

A

Junctional complexes (terminal bars)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When is enamel in an amorphous state rather than in rods?

A 
initial enamel (tomes process is not yet formed)
outermost enamel (tomes process have retracted)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are tomes processes responsible for?

A

forming the enamel rod structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Disruption of the proteins in the unique basal lamina at the external surface of enamel can result in what?

A

enamel Hypoplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Infiltration and incorporation of calcium ions into crystals occurs during which mature ameloblast conformation?

A

Ruffled cell

*Also secretes proteolytic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The diffusion out of protein fragments from the enamel, occurs during which mature ameloblast conformation?

A

Smooth cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The last secretory product of ameloblasts is called what?

A

Primary enamel cuticle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The remains of the reduced enamel epithelium merged with oral epithelium is called what?

A

Secondary enamel cuticle

*is removed due to mechanical forces

23
Q

The inner _______ of enamel are somewhat interwoven while the outer _______ is much straighter

A

2/3, 1/3

24
Q

What are three examples of enamel deposition proteins?

A

1-Amelogenin
2-Ameloblastin
3-Enamelin

25
Q

Only expressed while enamel is being produced, which protein restricts lateral HA crystal growth laterally and is the main protein family (80-90%) in developing enamel? If you don’t have it what happens?

A

Amelogenin

*no rods without it which would mean brittle teeth

26
Q

Expressed all the way through maturation, which protein adheres ameloblasts to developing enamel and make up about 10% of the organic material in enamel? if you don’t have it what happens?

A

Ameloblastin

*no enamel without it

27
Q

Only present on the leading edge of enamel deposition, which protein possibly promotes crystal elongation and is least abundant (5%)? if you don’t have it what happens

A

Enamelin

*no enamel without it

28
Q

Found during enamel deposition, which protein is an MMP and chops up ameloblastin and enamelin, and is critical for removal of organic component of enamel? if you don’t have it what happens

A

Enamelysin

you get thin, immature enamel if you don’t have it.

29
Q

Secreted during modulation events of enamel maturation, which protein degrades amelogenins? what happens if you don’t have it?

A

Enamel matrix serine protease

you get immature enamel if you don’t have it

30
Q

Instead of using collagen, the basal lamina on the enamel is made up of what?

A

Other proteins such as ODAM and Amelotin

31
Q

Etching tends to be more effective by dissolving the enamel crystal how?

A

Inside out, along the core. Carbonated apatite in core are most vulnerable

32
Q

What are the 3 types of enamel etching? Why are there 3 different types?

A

Type I- Preferential removal of rods (most common)
Type II-Interrod enamel removed
Type III-Irregular and indiscriminate pattern (least common)

different types are likely due to a difference in the orientation of Rod/interrod enamel crystal

33
Q

What are three kinds of enamel attrition (wear)?

A

1-Abrasion (ie. aggressive brushing)
2-Abfraction (notch like cervical lesion caused by cyclical loading)
3-Erosion (Break down of crystals, acid attack)

34
Q

How does enamel change with age?

A 
1-Color (darkness, stain, thin enamel)
2-change in Surface layer chemistry (fluoride)
3-Decrease water content
4-Increased brittleness
5-Decreased permeability
35
Q

What are the three categories of structural features of enamel?

A

1-Periodic features (Striae of Retzius, cross striations)
2-Optical features (Hunter-Schreger bands, gnarled enamel)
3-Histological features (tufts, lamellae, spindles)

36
Q

Longitudinal lines running from DEJ to enamel surface with increased organic content, likely due to cohorts of ameloblasts activating at the same time are called what?

A

Striae of Retzius

*Follow appositional growth pattern, may indicate weekly rhythm in enamel deposition

37
Q

What is an example of an accentuated striae indicative of physiological disturbance? What does this reflect?

A 
Neonatal line (birth line)
refelects physiologic changes occuring during birth. found in all primary teeth and sometimes cusps of permanent
38
Q

Visible on the enamel surface, what optical feature are manifestations of Striae of Retzius?

A

Perikymata

39
Q

Running at a right angle to the rod direction, what feature is indicative of daily, cyclical deposition of enamel?

A

Cross Striations

*roughly 4 um/day which is how far apart these striations are

40
Q

An optical phenomenon caused by light scattering off alternating rods, appearing as alternating light/dark bands are called what?

A

Bands of Hunter-Schreger

*Extend 2/3 distance from DEJ to surface. Outer 1/3 is straighter

41
Q

Mostly seen around the DEJ under cusps, what feature forms complex twisting rods?

A

Gnarled enamel

42
Q

Projecting about 1/3-1/2 into enamel, what feature contains more enamel proteins and thus are hypo calcified and look like cracks or grass?

A

Enamel tufts

*Possibly due to initial crowding of ameloblasts, gives the enamel a bit of “give”, helping to prevent fracture

43
Q

Appearing as cracks transversing the length of enamel, what feature is an area where enamel proteins were not completely removed? What is the possible function of these?

A

Enamel Lamellae

possibly give the enamel flexible support to resist fracture

notice these traverse the whole enamel where enamel tufts do not

44
Q

Resulting from odontoblastic processes that penetrate the enamel, what feature often appear at incisal and cuspal tips a very short distance into enamel?

A

Enamel Spindles

*not really enamel. they are really more dentin

45
Q

what are the names of the major enamel proteins?

A

amelogenins, ameloblastins, enamelin, tuftelin

46
Q

caries are thought to penetrate which part of the enamel?

A

the higher protein rod sheath areas between rod and interrod enamel

47
Q

What is the order of formation when it comes to rod enamel, protein sheath and interrod enamel?

A

first interrod enamel
then protein sheath
then rod enamel

48
Q

what is Modulation?

A

process by which water and proteins are removed from the enamel. There are fluctuations in the distal membrane of ameloblast layers ruffling and smoothing

49
Q

what is one benefit of enamel attrition?

A

pits and fissures may be eliminated

50
Q

what are 3 things that contribute to the changes in enamel over time that lead to decreased incidence of caries?

A

increased fluoride ion content
loss of pits and fissures due to attrition
adults consume less refined carbs

51
Q

why are the STriae of Retzius not straight?

A

because they follow the contour of the ‘cohort’ of ameloblasts

52
Q

what is genetic dysplasia of enamel?

A

developmental problems with tooth development/enamel formation

53
Q

T/F Amelo blasts are susceptible to physiological changes like birth and high fevers which results in their disruption for a time

A

True

54
Q

Excess fluoride during amelogenesis causes what?

A

hypermineralized enamel that appears chalk white or brown in color and can result in pits on the teeth

Oral Biology II COPY (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions