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):
1

Caries evolution

-White spot
-Enamel lesion
-Dentin lesion
-Pulpal lesion

2

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

-White spot
-demineralization or hypomineralization

3

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

-porous
-sound

4

Methods for studying incipient caries

-Clinical methods
-Laboratory methods

5

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

Densitometric
Tracing

6

Polarized Light Microscopy (PLM) makes use of
1) ____ and ____ of pores
2) Medium’s molecules ____ and _______.

1) Size and number
2) size and Refractive Index

7

Polarized Light Microscopy (PLM) Media

Quinoline
Thoulet’s medium
Water

8

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

Translucent Zone

9

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

Dark Zone

10

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

Body of lesion

11

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

remineralizing fluids

12

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

remineralization

13

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

Body of the lesion

14

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.

Surface Zone

15

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.

-Surface zone
-Dark zone

16

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

Dark zone and the Surface zone

17

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.

slight etching of the surface of the crystals

18

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

dentinal tubules

19

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

odontoblastic processes

20

The carious process destroys dentin by:
1. acid _______
2. acid _______
3. ______ enzymatic degradation

1. demineralization
2. hydrolysis
3. proteolytic

21

-softened discolored dentin which has
undergone demineralization and partial
decomposition.
-some calcium phosphate crystals remain
within the matrix.

Zone of necrotic dentin (Destruction)

22

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

Zone of necrotic dentin

23

-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.

Zone of infected tubules (bacterial invasion)

24

-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.

Zone of infected tubules

25

_________ 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.

Infected dentin

26

-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

Zone of demineralization

27

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

dead tracts

28

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

blind tracts

29

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

-sclerotic dentin
-Reparative or secondary dentin layer

30

Zones of dentinal-pulpal complex

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

31

Contains:
-Blood vessels and nerves
-Fibroblasts

Central zone

32

Contains:
-Fibroblasts
-Ground substance
-Collagen fibers
-macrophages
-undifferentiated mesenchymal cells

Cell-rich zone

33

Contains:
-Fibroblast
-Macrophages
-Undifferentiated mesenchymal cells
-Plexus of capillaries
-Nerve plexus of raschokow
-Ground substance

Cell-free zone (Zone of Weil)

34

Which structure has the following functions:
-production and maintenance of reticular fibers
-differentiation into odontoblasts

Fibroblast

35

Which structure has the following functions:
-Nutrition

Plexus of capillaries

36

Which structure has the following functions:
-Neural sensation of the pulp

Nerve plexus of raschkow

37

Which structure has the following functions:
-Metabolic changes and limits spread of infection

Ground substance

38

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

Odontoblastic zone

39

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

-primary dentin
-secondary dentin
-reparative or tertiary dentin

40

The reaction of pulp to an invading caries lesion is determined by the rate of the caries attack:
-Rapid: _____
-Slow: _____
-Arrested: _____

-Acute reaction
-No reaction to chronic reaction
-No reaction

41

Caries is an intermittent process with periods
of ______ alternating with periods of _____.

-rapid activity
-Quiescence

42

-bacterial toxins
-bacterial enzymes
-antigens
-chemotaxins
-organic acids
-products of tissue destruction

Irritants from invading caries lesion

43

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

Dead Tracts

44

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

reparative dentin

45

The amount of reparative dentin is directly
proportional to the amount of ________, but inversely proportional to the rate of _______.

-primary dentin
destroyed
-the carious attack

46

-plasma proteins
-immunoglobulins
-complement proteins

products of the inflammatory response

47

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.

bacterial activity

48

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

1.1 mm

49

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

0.5 mm

50

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

1. sclerotic dentin
2. dentin
3. pulp

51

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)

-peritubular dentin
-apatite & whitlockite crystals