Dentin (Exam II) Flashcards

1
Q

Dentin is ____ % mineral, ____ % organic, ____ % water

A

70% mineral
20% organic
10% water

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2
Q

The mineral components of dentin include:

A

Calcium hydroxyapatite
Trace amounts of calcium carbonate, fluoride, magnesium & zinc

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3
Q

What type of collagen is found in the organic component of dentin?

A

Type I collagen & trace amounts of type III & V

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4
Q

50% of the noncollagenous proteins in the organic component of dentin are:

A

phosphoprotein

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5
Q

Sialoprotein, sialophosphoprotein, proteoglycans, glycosaminoglycans, osteonectin & osteopontin are all part of the _____ structural component of dentin

A

Organic

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6
Q

The type I collagen of dentin is slightly different that of bone, because:

  1. Higher ratio of ____ & ____
  2. Higher prevalence of ___
  3. Higher level of _____
  4. Random orientation of the _____
A
  1. Proline & hydroxyproline
  2. Molecular cross-linking
  3. Bound water
  4. Hydroxyapatite crystals
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7
Q

The non-collagenous dentin matrix proteins include: (5)

A
  1. Proteoglycans
  2. Glycosaminoglycans
  3. Carboxy-glutamate-containing protein (Gla-proteins)
  4. Osteonectin
  5. Osteopontin
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8
Q

The dentin matrix non-collagenous proteoglycans include: (2)

A
  1. Biglycan
  2. Decorin
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9
Q

The dentin matrix non-collagenous glycosaminoglycans include: (2)

A

Chondroitin-4 sulfate
Chondroitin-6 sulfate

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10
Q

Life stages of the odontoblast include:

A
  1. Pre-odontoblast
  2. Secretory odontoblast
  3. Transitional odontoblast
  4. Resting odontoblast
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11
Q

What is the precursor to pre-odontoblasts?

A

Ectomesenchymal cells

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12
Q

The stimulus for ectomesenchymal cell differentiation to pre-odontoblasts appears to be derived from _____ located within the basal lamina of the inner enamel epithelium (IEE)

A

Fibronectin

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13
Q

Several growth factors of the pre-odontoblasts are derived from the:

A

IEE (inner enamel epithelium)

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14
Q

Causes all the cells to align themselves along the basal lamina, assume polarity & differentiate into secretory cells

A

Pre-odontoblast fibronectin receptors

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15
Q

Growth factors secreted by the IEE that play a role in odontoblast differentiation include:

A
  1. Transforming growth factors (TGF)
  2. Bone morphogenetic proteins (BMP)
  3. Insulin-like growth factor (IGF)
  4. Fibroblast growth factor (FGF)
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16
Q

Complete differentiation requires the cell to divide multiple times which allows the cells to express the appropriate receptors able to to bind ____ localized to the IEE basal lamina:

A

Growth factors

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17
Q

In odontoblast differentiation, the last mitotic division results in a mature odontoblast & a daughter cell that is forced into the ____ cell layer

A

Subodontoblastic

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18
Q

Cells in the subodontoblastic layer, because they are removed from the sphere of influence of the IEE, represent ______

A

Ectomesenchymal cells

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19
Q

The ectomesenchymal cells in the subodontoblastic layer are exposed to the entire cascade of developmental controls for _____

A

Odontoblastic differentiation

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20
Q

What control of odontoblastic differentiation are the ectomesenchymal cells not exposed to?

A

Inductive influence of growth factors associated with IEE

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21
Q

It is thought that this cell population is responsible for the reparative odontoblast that differentiate from pulpal cells:

A

Ectomesenchymal cells

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22
Q

The matrix vesicles of the secretory odontoblasts contain everything you need to harden & crystalize the:

A

Enamel matrix

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23
Q

The secretory odontoblasts are ____ cells with extensive junctional complexes & gap junction formations:

A

Tall columnar cells

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24
Q

The secretory odontoblasts exhibit significant ______ activity

A

Alkaline phosphatase

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25
Q

The secretory odontoblasts secrete what types of collagen?

A

Mainly type I & traces of type III & V

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26
Q

The secretory odontoblasts secrete what matrix vesicles: (7)

A
  1. Phospholipids
  2. Alkaline phosphatase
  3. Phosphoproteins
  4. Pyrophosphatase
  5. Calcium & phosphate
  6. Annexin
  7. Calcium hydroxyapatite crystallites
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27
Q

Matrix vesicle secreted by the secretory odontoblasts that is responsible for mediating the flow of calcium into the matrix vesicle & also serves as a collagen receptors that binds matrix vesicles to collagen:

A

Annexin

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28
Q

50-100 micrometers thick layer of first formed dentin

A

Mantle dentin

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29
Q

Mantle dentin matrix consists of what type of collagen?

A

Type I & III

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30
Q

Describe the arrangement of collagen fibers in the matrix of mantle dentin:

A

Arranged perpendicular to basal lamina in the IEE

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31
Q

The organic matrix of dentin is deposited:

A

Incrementally

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32
Q

What is the rate of the incremental deposition of the organic matrix of dentin?

A

4 to 8 micrometers per 24 hours

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33
Q

Incremental lines in dentin (hypomineralized areas) are thought to represent a hesitation in matrix & subsequently altered mineralization that occurs after 4-20 days of matrix deposition

A

Lines of Von Ebner

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34
Q

Deficiencies & irregularities in _____ result in areas of hypomineralization, commonly appear as accentuated incremental lines for areas of interglobular dentin

A

Dentinogenesis

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35
Q

Give two examples of deficiencies or irregularities in dentinogenesis resulting in hypomineralization

A
  1. Neonatal line
  2. Contour lines of Owen
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36
Q

Dentin tubules are tapered and are wider at the _____ and narrower at the ____

A

Pulpal surface
DEJ

37
Q

Because of the decrease in ______ of the ___ chamber, the number of dentinal tubules per unit area at the pulpal surface is twice as many compared to at the DEJ

A

Volume; pulp

38
Q

wWhat has more dentinal tubules per unit area-

Pulpal surface or DEJ?

A

Twice as many at pulpal surface compared to DEJ

39
Q

The more calcified, more resistant to etch dentin

A

Peritubular dentin

40
Q

Dentin between the dentin

A

Demineralized intertubular dentin

41
Q

As you get closer to the basal lamina (to the basement membrane) the processes of the cell tend to branch to increase surface area for more attachment points:

A

Anastomosis of dentin

42
Q

Pattern of mineralization in which everything is calcified uniformly

A

Linear mineralization

43
Q

They zone of globular rather linear formed dentin seen in the crowns of teeth & root surfaces

A

Interglobular dentin

44
Q

Interglobular dentin is characterized by _____ that are unmineralized or hypomineralized dentin between the normal calcified dentinal layers

A

interglobular spaces

45
Q

What are the two methods of mineralization we see in dentin?

A

Linear & globular

46
Q

A granular-appearing layer in the dentin of the root adjacent to the cementum. Possibly comprised of hypomineralized interglobular dentin:

A

Tome’s granular layer

47
Q

All the dentin (except mantle dentin) formed up to the time the tooth achieves functional occlusion

A

Primary dentin

48
Q

All the dentin formed (except tertiary dentin) after tooth achieves functinoal occlusion

A

Secondary dentin

49
Q

Dentin tubules that are void of the odontoblastic process. They are generally filled with air or organic debris and look black in transmitted light microscopy

A

Dead tracts

50
Q

Dentin in which the tubules are occluded with mineral. The dentin is non-tubular and is nearly transparent. Incidence of occurrence increases with increasing age of the patient. May also be tertiary (reparative) dentin:

A

Sclerotic dentin

51
Q

The organic matrix is deposited in increments of 4-8 micrometers per 24 hours

A

Incremental lines of Von Ebner

52
Q

Occur after 4-20 days of matrix deposition and are thought to represent hesitations in matrix deposition & therefore altered mineralization:

A

Lines of Von Ebner

53
Q

Exaggerated lines of von Ebner that occur during periods of altered cell metabolism:

A

Neonatal Line & Contour lines of Owen

54
Q

Dentin deposited by newly differentiated odontoblasts at the site of pulpal trauma. A defensive reaction attempting to wall off the pulp from the suite of injury:

A

Tertiary dentin (reparative dentin)

55
Q

Cells in the subodontoblastic layer, once exposed to ______ released by stimulated pulpal cells differentiated and form the matrix of ______

A

Growth factors
Matrix of reparative dentin

56
Q

The growth factors released by stimulated pulpal cells that form the matrix of reparative dentin after exposure to the cells in the subodontoblastic layers

A
  1. Bone morphogenic protein (BMP)
  2. Insulin-like growth factor (IFG)
  3. Fibroblast growth factor (FGF)
  4. Dentin matrix protein (DMP)
57
Q

Hereditary defect that results in bluish-gray teeth with an opalescent sheen. The enamel is normal but chips off due to lack of support by the abnormal dentin. The pulp chamber & canals are generally obliterated by the defective dentin formation:

A

Dentinogenesis imperfecta

58
Q

What important protein is missing when looking at the DEJ in patients with dentinogenesis imperfecta:

A

Tuftelin

59
Q

When looking at the teeth through X-ray of a patient with dentinogenesis imperfecta, you can see that:

A

Pulp chambers are completely obliterated

60
Q

Loss by wear of surface caused by tooth to tooth contact, during mastication or parafunction. Matching wear on occluding surfaces, & shiny facets on amalgam contacts are common:

A

Attrition

61
Q

In attrition, enamel & dentin wear is at the same _____. Possible fracture of cusps or restorations appear in this disease.

A

Rate

62
Q

Dental attrition is typically due to:

A

Bruxism

63
Q

Loss of hard dental tissue by chemical processeses

A

Dental erosion

64
Q

Broad concavities, with cupping of occlusal surfaces & dentin exposure. Incisal translucency aas well as wear on non-occluding surface. Amalgam restorations appear “raised” & have a non-tarnished appearance. Patients are usually hypersensitive & this is very common with GERD patients

A

Dental erosion

65
Q

The caries balance is between:

A

Pathological factors & protective factors

66
Q

Pathological factors found in the caries balance:

A
  1. acid-producing bacteria
  2. Frequently eating/drinking of fermentable carbohydrate
  3. Subnormal saliva flow and/or function
67
Q

Protective factors found in the caries balance:

A
  1. saliva flow & components
  2. fluoride, calcium & phosphate
  3. antibacterials: chlorhexadine, iodine, xylitol, etc.
68
Q

Many hydroxyapatite crystal exhibit a core of relatively more ______

A

Soluble carbonate apatite

69
Q

The carbonate substitution in the lattice structure of enamel occurs primarily at the ______ in dental caries:

A

phosphate sites

70
Q

In dental caries the core of carbonate apatite is eroded preferentially by acids due to its greater susceptibility to _____

A

dissolution

71
Q

_____ may substitute for hydroxyl ions in hydroxyapatite, conferring greater stability & resistance to acidic dissolution

A

Fluoride

72
Q

In dental caries, acid preferentially attacks the end of the crystals & the crystal is eroded along its _____ & from the inside toward the _____

A

C axis; edges

73
Q

Bacteria responsible for enamel/dentin caries includes:
(4)

A

Strep mutans
Strep sorbrinus
Strep gordonii
Lactobacillus acidophilus

74
Q

Bacteria responsible for root caries:

A

Actinomyces viscosus

75
Q

As the process of dental caries (acid dissolution of the enamel) reaches DEJ, it spreads _____ due to _____

A

Laterally; due to branching of dentinal tubules at DEJ

76
Q

After the caries spreads laterally once it reaches the DEJ it then penetrates towards:

A

The pulp within the dentinal tubules

77
Q

After the caries penetrates towards the pulp within the dentinal tubules, a _______ is produced beneath the adjacent enamel surface

A

Substantial cavitation

78
Q

After a substantial cavitation is produced beneath the adjacent enamel surface, there is initially a caries lesion that exhibits a small opening or orifice in the enamel & pyramidal shaped dentin lesion with the apex of the pyramid pointing towards the:

A

Tooth pulp

79
Q

1 in 5 adults suffer from:

A

Dentinal sensitivity

80
Q

The teeth most commonly affected by dentinal sensitivity:

A

Cuspids & bicuspids

81
Q

Stimuli associated with dentinal sensitivity include: (6)

A
  1. Cold/hot beverages
  2. Sweet or sour (acidic) food or beverages
  3. Overly aggressive brushing
  4. Acidogenic plaque bacteria
  5. Cosmetic bleaching of teeth
  6. Clenching or bruxism
82
Q

Direct stimulation of nerve endings in dentinal tubules describes what theory of dentinal sensitivity?

A

Direct innervation theory

83
Q

Stimulation of odontoblasts that are coupled to nerves in the pulp describes what theory of dentinal sensitivity?

A

Transduction theory

84
Q

Stimulation of dentinal tubules or exposed odontoblastic cell processes causes movement of tissue fluids within dentin tubules that, in turn, stimulates nerve endings in close association with dentin at the dentin/pulpal interface. This describes what theory of dentinal sensitivity?

A

Brannstrom’s hydrodynamic theory

85
Q

Branntrom’s hydrodynamic theory has its roots in:

A

Charle’s Law

86
Q

The volume of gas (or fluid) is directly proportional to the amount of heat applied at a constant pressure:

A

Charle’s Law

87
Q

If heat is applied to a sensitive tooth, the volume of the fluid in the tubules increases, causing stimulation of the:

A

Nerve endings

88
Q

If cold is applied to a sensitive tooth, the volume of the fluids in the tubules decreases, causing movement in the fluid & stimulation of:

A

Nerve endings