Caries of Enamel (Amaechi 6) Flashcards Preview

Exam 2: DHHD 5001 > Caries of Enamel (Amaechi 6) > Flashcards

Flashcards in Caries of Enamel (Amaechi 6) Deck (51)
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1
Q

Caries evolution

A
  • White spot
  • Enamel lesion
  • Dentin lesion
  • Pulpal lesion
2
Q

The first clinical sign of incipient caries is _______ due to change in optical properties of enamel with _________.

A
  • White spot

- demineralization or hypomineralization

3
Q

Enamel surface of early lesion is micro-____ but macroscopically _____.

A
  • porous

- sound

4
Q

Methods for studying incipient caries

A
  • Clinical methods

- Laboratory methods

5
Q

Transverse Microradiography (TMR)
is _______ of the
mineral level in
incipient caries.

A

Densitometric

Tracing

6
Q

Polarized Light Microscopy (PLM) makes use of

1) ____ and ____ of pores
2) Medium’s molecules ____ and _______.

A

1) Size and number

2) size and Refractive Index

7
Q

Polarized Light Microscopy (PLM) Media

A

Quinoline
Thoulet’s medium
Water

8
Q

1) Advancing front of the lesion
2) 50% of cases
3) 1% pore volume (normal enamel 0.1%)
4 1.2% loss of mineral by volume
5) Rise in fluoride concentration
6) Fall in carbonate, mg, Ca and PO4
7) No loss of organic material

A

Translucent Zone

9
Q

1) Superficial to translucent zone
2) Present in 90-95% of cases
3) 2-4% pore volume
4) 6.3% loss of mineral by volume
5) Has some pores smaller than those of translucent zone suggesting remineralization

A

Dark Zone

10
Q

During remineralization the Dark zone increases in size, extending into area previously identified as _______.

A

Body of lesion

11
Q

Lesions without dark areas show normal dark zones following exposure to ________.

A

remineralizing fluids

12
Q

The appearance of a Dark zone was due to _______ occurring at the advancing front of the lesion.

A

remineralization

13
Q

1) Has lost a much larger proportion of its mineral matter
2) Always present
3) 5-25% pore volume
4) 24% loss of mineral by volume
5) Increase in bound water and organic content due to saliva diffusion into the zone

A

Body of the lesion

14
Q

1) About 10-100 µm thick
2) Always present
3) 1-5% pore volume
4) 10% loss of mineral by volume
5) Higher in fluoride and protein. Lower in magnesium and carbonate.

A

Surface Zone

15
Q

A remineralized Lesion showed a wider ______, and a wider _____ than prior to remineralization, at the expense of reduction
in the size of the Body of the lesion.

A
  • Surface zone

- Dark zone

16
Q

The _______ and the _____ therefore represent areas of active remineralization,
even during lesion formation.

A

Dark zone and the Surface zone

17
Q

Crystal dissolution begins
at the center or core of
the hydroxyapatite crystal. The intercrystalline spaces were increased with caries process, due to ________ as evidenced by irregularity of the margins.

A

slight etching of the surface of the crystals

18
Q

The dentin is composed, structurally, of ________ extending from the predentin border to the dentino-enamel junction (DEJ).

A

dentinal tubules

19
Q

The dentinal tubules which are filled with dentinal fluid house the _______.

A

odontoblastic processes

20
Q

The carious process destroys dentin by:

  1. acid _______
  2. acid _______
  3. ______ enzymatic degradation
A
  1. demineralization
  2. hydrolysis
  3. proteolytic
21
Q
-softened discolored dentin which has 
undergone demineralization and partial 
decomposition.
-some calcium phosphate crystals remain 
within the matrix.
A

Zone of necrotic dentin (Destruction)

22
Q

-collagen fibers and collagen fiber
breakdown.
-large masses of bacteria which correspond to
foci of liquefaction
-gas products may produce ellipsoidal spaces

A

Zone of necrotic dentin

23
Q

-bacteria confined within the dentinal tubules.
-dentinal tubules may be distended and in
some places destroyed as the result of acid
demineralization.
-confluence of tubules produce bacteria-filled
pools within the dentin.

A

Zone of infected tubules (bacterial invasion)

24
Q
  • uninfected tubules are frequently found interspersed among infected tubules.
  • single infected tubules may extend deep into intact dentin, emphasizing the irregular pattern of bacterial penetration.
  • collagen breakdown.
  • depolymerization of the nonfibrous ground substance of dentin.
  • large number of hydrolytic enzymes.
A

Zone of infected tubules

25
Q

_________ is the irreversible demineralized and denatured layer of dentin, not reparable and with bacterial invasion; it fells very soft, moist and easy to remove with a spoon excavator.

A

Infected dentin

26
Q
  • evidence of decalcification
  • no penetration of bacteria
  • dentinal tubules appear fairly normal
  • loss of peritubular dentin
  • decrease of crystal size - hydroxyapatite
  • leaf-shaped crystals - octacalcium phosphate
  • large rounded isodiametric crystals - whitlockite
A

Zone of demineralization

27
Q

Zone of sclerosis: If dentin is damaged the odontoblastic processes die leaving empty dentinal tubules which form areas of ________.

A

dead tracts

28
Q

Zone of sclerosis: Dead tracts become filled with mineral and are called ______.

A

blind tracts

29
Q

Zone of sclerosis: The dentin of blind tracts is known as _______.
Below this area is an area of _______.

A
  • sclerotic dentin

- Reparative or secondary dentin layer

30
Q

Zones of dentinal-pulpal complex

A
  1. Central zone
  2. Cell-rich zone
  3. Cell-free zone (zone of Weil)
  4. Odontoblastic zone
31
Q

Contains:

  • Blood vessels and nerves
  • Fibroblasts
A

Central zone

32
Q

Contains:

  • Fibroblasts
  • Ground substance
  • Collagen fibers
  • macrophages
  • undifferentiated mesenchymal cells
A

Cell-rich zone

33
Q

Contains:

  • Fibroblast
  • Macrophages
  • Undifferentiated mesenchymal cells
  • Plexus of capillaries
  • Nerve plexus of raschokow
  • Ground substance
A

Cell-free zone (Zone of Weil)

34
Q

Which structure has the following functions:

  • production and maintenance of reticular fibers
  • differentiation into odontoblasts
A

Fibroblast

35
Q

Which structure has the following functions:

-Nutrition

A

Plexus of capillaries

36
Q

Which structure has the following functions:

-Neural sensation of the pulp

A

Nerve plexus of raschkow

37
Q

Which structure has the following functions:

-Metabolic changes and limits spread of infection

A

Ground substance

38
Q

Contains:
-cell bodies of the odontoblasts from which the odontoblastic processes extend through the dentinal tubules into the dentin

A

Odontoblastic zone

39
Q

Odontoblast function:

  • formation of the tooth by the deposition of ______.
  • reduction of the pulp chamber by the deposition of ______ through the life of the tooth
  • deposition of _______ to protect the tooth against noxious stimulus
A
  • primary dentin
  • secondary dentin
  • reparative or tertiary dentin
40
Q

The reaction of pulp to an invading caries lesion is determined by the rate of the caries attack:

  • Rapid: _____
  • Slow: _____
  • Arrested: _____
A
  • Acute reaction
  • No reaction to chronic reaction
  • No reaction
41
Q

Caries is an intermittent process with periods

of ______ alternating with periods of _____.

A
  • rapid activity

- Quiescence

42
Q
  • bacterial toxins
  • bacterial enzymes
  • antigens
  • chemotaxins
  • organic acids
  • products of tissue destruction
A

Irritants from invading caries lesion

43
Q

Permeability increased by the early death of
the odontoblast and its process from
aggressive caries with consequent formation
of _______.

A

Dead Tracts

44
Q

Maintenance of dentin thickness by formation of _______ through secretion by odontoblasts of collagen, amorphous material or large apatite

A

reparative dentin

45
Q

The amount of reparative dentin is directly

proportional to the amount of ________, but inversely proportional to the rate of _______.

A

-primary dentin
destroyed
-the carious attack

46
Q
  • plasma proteins
  • immunoglobulins
  • complement proteins
A

products of the inflammatory response

47
Q

Products of the inflammatory response also diffuse from the pulp back into the carious process in an effort to inhibit the ______ of the carious lesion.

A

bacterial activity

48
Q

Penetration in the dentin (including reparative
dentin) of bacteria within ____ of the pulp
produces a negligible inflammatory response
of the pulp.

A

1.1 mm

49
Q

Penetration within ____ of the pulp produces a significant increase in the inflammatory response.

A

0.5 mm

50
Q

A decrease in the permeability of dentin by:

  1. Formation of _____ through acceleration of peritubular dentin formation to occlude tubules
  2. Reduction in ____ permeability
  3. Shielding of the ____ from irritation
A
  1. sclerotic dentin
  2. dentin
  3. pulp
51
Q

Pulp Responses:
1. Caries deeply penetrated the enamel or barely penetrated the dentin
2. Increase in the rate of formation of _______.
3. Reduction in dentin permeability
4. Shielding of the pulp from irritation
5. partially or completely filled dentinal tubules
with mineral deposits such as ____ and _____. (Dentinal sclerosis)

A
  • peritubular dentin

- apatite & whitlockite crystals