Dentine Flashcards
1
Q
Which of the following dentinal layers is more mineralized? A. Peritubular dentin B. Inter-tubular dentin C. Dentinal tubules D. Circumpulpal dentin
A
A
2
Q
The type of tertiary dentin which contains cellular inclusions is found in: A. Sclerotic dentin B. Mantle dentin C. Predentin D. Osteodentin
A
d
3
Q
The dentin adjacent to the dentinoenamel junction is called the : A. Mantle dentin B. Circumpulpal dentin C. Predentin D. Osteodentin
A
D
4
Q
The main bulk of dentin is formed by : A. Peritubular dentin B. Mantle dentin C. Inter tubular dentin D. Predentin
A
C
5
Q
Inter globular dentin results due to: A. Failure of coalescence of calcospherites B. Fracture of the dentin C. Artifact in light microscopy D. Disturbance in dentinal tubules
A
A
6
Q
Dentinogenesis by odontoblasts first behins at : A. Pulpal end B. Cusp tip C. Tooth bud stage D. Cervical area
A
B
7
Q
Sclerotic dentin has following features : A. Caries susceptible B. Insensitive C. Hypersensitive D. Resistant to caries
A
D
8
Q
The microhardness of dentin is about: A. 1/2 that of enmel B. 1/7 that of enamel C. 1/4 that of enamel D. 1/5 that of enamel
A
D
9
Q
Shape of the crown and the size of the roots is determined by: A. Pulp B. Dentin C. Enamel D. Cementum
A
B
10
Q
Organic portion can be separated from the mineral by : A. Incineration / Organic chelation B. Decalcification C. Devitrification D. Combustion
A
A
11
Q
Formula of hydroxyapatite crystal is : A. Ca3(Po4)2.CaCO3 B. 3Ca3(Po4)2. Ca(OH)2 C. CaPo4. Ca(OH)2 D. None of the above
A
B
12
Q
The type of dentin that is formed prior to root completion is : A. Inter tubular dentin B. Peritubular dentin C. Circumpulpal dentin D. Secondary dentin
A
C
13
Q
Accentuated incremental lines in dentin due to disturbances in matrix and mineralisation process is: A. Incremental lines of Retzius B. Incremental lines of von Ebner C. Contour lines of Owen D. None of the above
A
C
14
Q
Dentinal tubules are calcified in: A. Sclerotic dentin B. Secondary dentin C. Primary dentin D. Interglobular dentin
A
A
15
Q
During the formation of primary teeth:
A. Enamel forms more cervically than dentin
B. Enamel forms faster than dentin
C. Dentin forms faster than enamel
D. Processes of their cells remain in content with each other
A
c
16
Q
Matrix vesicles : A. Are found in mantle dentin B. Contain collagen C. Produce alkaline phosphatase D. Inhibit mineralization
A
A
17
Q
During hydrodynamic theory movement of fluids in dentinal tubules cause:
A. Movement of odontoblasts
B. Touch the nerves of the pulp to cause pain
C. Minimum effect on odontoblast
D. Stimulation of odontoblastic process
A
B
18
Q
Which of the areas of the tooth is most sensitive during cavity preparation : A. Enamel (anterior teeth) B. Enamel (posterior teeth) C. Dentin D. Dentinoenamel junction
A
D
19
Q
Matrix vesicles play important role in the mineralization of : A. Dentin B. Enamel C. Pulp D. Periodontal ligament
A
A
20
Q
False statement regarding interglobular dentin is :
A. The term interglobular dentin refers to organic matrix that remains unmineralized because the mineralising globules fail to coalesce
B. This occurs most often in the circumpulpal dentin just below the mantle dentin
C. Where the pattern of mineralization is likely to be appositional than globular
D. Large areas of interglobular dentin is a characteristic feature of childhood hypophosphatasia
A
C
21
Q
Interglobular spaces:
a- Do not contain dentinal tubules.
b- Do not contain type I collagen.
c- Are formed during the course of globular mineralization.
d- Are seen only in secondary dentin.
A
C
22
Q
Which would not be present in a ground section? a- Inorganic crystals. b-Odontoblast. c- Interglobular space. d- Dentinal tubules.
A
B
23
Q
Which of the following is MOST likely to be found in the dentinal tubules: a- Tomes' fibers. b- Oxytalan fibers. c- Tomes' process. d- Thick collagen fibers.
A
A
24
Q
Which of the following is true of peritubular dentin ?It :
a- Is less mineralized than intertubular dentin.
b- May be considered as intratubular dentin.
c- Is best visualized in decalcified sections.
d- Is found in the interglobular dentin.
A
B
25
Which of the following is not present in odontoblasts?
a- Golgi saccules and vesicles.
b- Rough endoplasmic reticulum.
c- Desmosome-like junctions.
d- Numerous processes forming a striated border.
D
26
Which of the following is true:
a- A layer of predentin is found between primary and secondary dentin.
b- Dentinal tubules do not pass through interglobular dentin.
c- The physiological secondary dentin contain dentinal tubules.
d- Many large collagenous fiber bundles are found in the dentinal tubules.
C
27
Reparative dentin:
a- Contain regular and numerous dentinal tubules.
b- Obliterates the apical foramen.
c- Forms on localized regions of the pulpal surface of the dentin.
d- Formation is induced by the cells of the inner dental epithelium.
C
28
Matrix vesicles are present during:
a- The initial mineralization of dentin.
b- The initial mineralization of enamel.
c- The initial mineralization of cementicles.
d- The initial mineralization of denticles.
A
29
Obliteration of the dentinal tubules by mineral deposits:
a- Occurs only when the dentin becomes exposed to the oral fluids.
b- Produces dead tracts.
c- First occurs in predentin.
d- Is seen in sclerotic and transparent dentine.
D
30
Tome's granular layer is:
a- An extension of odontoblast processes into enamel.
b- A region lacking dentinal tubules.
c- Following the incremental lines.
d- Derived from the epithelial rests of Malassez.
B
31
Amelogenesis and dentinogenesis are similar in which respect?
a- Both processes involve the secretion of collagenous fibers impregnation with hydroxy-apatite crystals.
b- Both processes involve maturation with hydroxyappatite crystals.
c- Both processes start simultaneously at the early crown stage.
d- Both processes continue throughout the life of the tooth.
B
32
```
Which of the following has the highest mineral content?
a- Predentin.
b- Peritubular dentin.
c- Intertubular dentin.
d- Cementum.
```
B
33
-Dentin is a variety of Connective tissue because it:
a- is elastic and contains mucopolysaccharides.
b- contains collagen fibers and cell processes derived from mesenchyme.
c- contains inorganic cells.
d- has few cells and much intercellular material.
B
34
Cementum deposition cervically on enamel surface is due to:
a- premature degeneration of epithelial root sheath of Hertwig.
b- loss of reduced enamel epithelium.
c- persistence of epithelial root sheath of Hertwig.
d- cementoblasts coming from dental sac.
B
35
Obliteration of dentinal tubules by minerals will result in:
a- formation of dead tracts.
b- formation of secondary dentin.
c- formation of sclerosed dentin.
d- formation of irregular or reparative dentin.
C
36
formation of matrix vesicles in calcification of dentin is limited to:
a- circumpulpal dentin. b- Mantle dentin.
c- all types of dentin. d- non of the above.
B
