Other possible MCQ 6,7,8

Question 1

Ameloblasts produce _______ as they migrate.
a. cementoid
b. enamel rods
c. epithelial rests
d. dentinal tubules

Answer 1

b. enamel rods

Question 2

Which of the following best defines incremental lines?

a. Ridges visible on the surface of enamel

b. Termination of dentinal tubules in enamel

c. Alternating dark and light bands of enamel rod groups

d. Lines that result from the rhythmic recurrent deposition of enamel

Answer 2

d. Lines that result from the rhythmic recurrent deposition of enamel

Question 3

Which of the following best defines perikymata?

a. Termination of dentinal tubules in enamel.

b. Alternating dark and light bands of enamel rod groups.

c. Growth lines visible as ridges on the surface of enamel.

d. Lines that result from the rhythmic recurrent deposition of enamel

Answer 3

c. Growth lines visible as ridges on the surface of enamel.

Question 4

Enamel is composed of ______ hydroxyapatite.
a. 26%
b. 53%
c. 90%
d. 96%

Answer 4

d. 96%

Question 5

Enamel is approximately ______ thick at the occlusal or incisal surface.
1 μm
9 μm
2.5 mm
4.5 mm

Answer 5

2.5 mm

Question 6

Which type of enamel contains many tiny spaces stained with pigment?
a. Gnarled
b. Prenatal
c. Postnatal
d. Prismless

Answer 6

c. Postnatal

Question 7

Perikymata are found in which location?
a. Cusp tip
b. Cervical third of the root
c. Middle third of the crown’s lingual aspect
d. Cervical third of the crown’s facial aspect

Answer 7

d. Cervical third of the crown’s facial aspect

Question 8

Which part of the enamel rod is most sensitive to demineralization?
a. Tail
b. Core
c. Head
d. Sheath

Answer 8

b. Core

Question 9

Which of the following best defines the neonatal line?
a. An accentuated incremental line.
b. A defect caused by the misdirection of enamel rods.
c. Light and dark enamel rod groups, made visible with light.
d. A series of dark growth rings noticeable in the cross section of enamel.

Answer 9

a. An accentuated incremental line.

Question 10

Which statement is true?
a. Tubular defects are associated with enamel lamellae.
b. Lamellae provide increased resistance to dental caries.
c. Breathing cold air is a risk factor in developing enamel lamellae.
d. Enamel lamellae are microscopic cracks in the surface of enamel.

Answer 10

c. Breathing cold air is a risk factor in developing enamel lamellae.

Question 11

An enamel ______ houses a small extension of a living odontoblast.
a. rod
b. tuft
c. spindle
d. lamellae

Answer 11

c. spindle

Question 12

The organic component of enamel is called

Answer 12

enamelin

Question 13

Enamel lamellae are not tubular defects, but leaf-like tracts. T or F

Answer 13

true

Question 14

Which of the following does not facilitate the spread of dental caries?
a. Enamel tufts
b. Enamel lamellae
c. Incremental lines
d. Prismless enamel

Answer 14

d. Prismless enamel

Question 15

A developmental defect at the dentinoenamel junction of enamel that is filled with organic material is called (a/an)
a. enamel rod.
b. enamel tuft.
c. enamel lamellae.
d. enamel spindle.

Answer 15

b. enamel tuft.

Question 16

Two ameloblast cells form the enamel rod
a. head.
b. neck.
c. body.
d. tail.

Answer 16

b. neck.

Question 17

The surface of the enamel rod is called the rod
a. margin.
b. periphery.
c. sheath.
d. core.

Answer 17

c. sheath.

Question 18

The organic component of enamel is called
a. hydroxyapatite.
b. enamelin.
c. gnarled enamel.
d. perikymata.

Answer 18

b. enamelin.

Question 19

Ameloblasts migrate away from the dentinoenamel junction as they produce enamel rods. T or F

Answer 19

true

Question 20

Ameloblasts travel along parallel paths to produce straight enamel rods.

Answer 20

false

Question 21

Light and dark enamel rod groups are known as striae of Retzius. T or F

Answer 21

false

Question 22

Ameloblasts deposit 4 μm of enamel rods daily. T or F

Answer 22

true

Question 23

Enamel varies in density and hardness. T or F

Answer 23

true

Question 24

Lamellae are cracks in the surface of enamel and are visible to the naked eye. T or F

Answer 24

true

Question 25

Enamel rods extend from the dentinoenamel junction to the enamel outer surface. T or F

Answer 25

true

Question 26

Each enamel rod is formed by a single ameloblast. T or F

Answer 26

false

Question 27

Enamel rods extend perpendicular to the dentoenamel junction, but curve slightly toward the cusp tip. T or F

Answer 27

true

Question 28

Hunter-Schreger bands extend through half- to two-thirds of the enamel. T or F

Answer 28

true

Question 29

Incremental lines result from the rhythmic, recurrent deposition of enamel. T or F

Answer 29

true

Question 30

Enamel lamellae are not tubular defects, but leaf-like tracts. T or F

Answer 30

True

Question 31

Prismless enamel is characterized by numerous and pronounced Hunter-Schreger bands. T or F

Answer 31

false

Question 32

Enamel is an impermeable tissue. T or F

Answer 32

false

Question 33

In the Hunter-Schreger phenomenon, adjacent rod groups lie at right angles to each other. T or F

Answer 33

true

Question 34

Etching the surface of enamel stimulates remineralization. T or F

Answer 34

false

Question 35

Which of the following best defines sclerotic dentin? a. The dentinal matrix that immediately surrounds the dentinal tubule. The first dentin formed and deposited at the dentinoenamel junction. c. Dentin directly underlying mantle dentin, comprising the bulk of primary dentin. d. Obliterated tubules, found mainly in areas of attrition, abrasion, fracture, and caries.

Answer 35

d. Obliterated tubules, found mainly in areas of attrition, abrasion, fracture, and caries.

Question 36

The granular layer of Tomes is located in the _________. a. dentin of the root b. dentin of the crown c. periodontal ligament dentin. d. cementum of the root

Answer 36

a. dentin of the root

Question 37

Which type of dentin forms to protect and maintain the vitality of the pulp? a. Mantle b. Sclerotic c. Peritubular d. Reactionary

Answer 37

d. Reactionary

Question 38

Which type of dentin separates mantle dentin from circumpulpal dentin? a. Granular b. Globular c. Transparent d. Reactionary

Answer 38

b. Globular

Question 39

_______ are extensions of the odontoblast process into enamel. a. Dead tracts b. Neonatal lines c. Enamel spindles d. Lines of von Ebner

Answer 39

c. Enamel spindles

Question 40

Dentin is _______ than enamel. a. harder b. more elastic c. a whiter shade d. less radiolucent

Answer 40

b. more elastic

Question 41

Which is the following is a hypermineralized collar of dentin surrounding the tubules? a. Sclerotic dentin b. Peritubular dentin c. Intertubular dentin d. Interglobular dentin

Answer 41

b. Peritubular dentin

Question 42

The appositional growth of dentin is apparent in which feature? a. Incremental lines b. Lateral canaliculi c. Transparent dentin d. Interglobular spaces

Answer 42

a. Incremental lines

Question 43

The major organic component of dentin is _______. a. water b. collagen c. enamelin d. hydroxyapatite

Answer 43

b. collagen

Question 44

Which type of dentin borders the pulp? a. Globular b. Predentin c. Reactionary d. Circumpulpal

Answer 44

b. Predentin

Question 45

Which type of dentin is formed prior to tooth function and is the major component of the crown and root of the tooth? a. Mantle dentin b. Circumpulpal dentin c. Secondary dentin d. Tertiary dentin

Answer 45

b. Circumpulpal dentin

Question 46

Odontoblastic injury during a cavity preparation usually results in which of the following forms of dentin? a. Primary mantle dentin b. Primary globular dentin c. Secondary dentin d. Tertiary dentin

Answer 46

d. Tertiary dentin

Question 47

Which term is preferred to describe when newly recruited (replacement) odontoblasts begin depositing dentin? a. Reactionary dentin b. Response dentin c. Reparative dentin d. Secondary dentin

Answer 47

c. Reparative dentin

Question 48

The defining characteristic of globular dentin is a. interglobular spaces. b. lamellae. c. The presence of ameloblasts. d. sclerotic dentin.

Answer 48

a. interglobular spaces.

Question 49

Incremental lines in dentin are also known as a. lines of von Ebner. b, the smear layer. c. the granular layer of Tomes. d. canaliculi.

Answer 49

a. lines of von Ebner.

Question 50

Sclerotic dentin is found in each of the following areas EXCEPT one. Which one is the EXCEPTION? a. Abrasion b. Fracture c. Living odontoblasts d. Caries of enamel

Answer 50

c. Living odontoblasts

Question 51

Peritubular dentin is not found in the dentinal tubules of interglobular dentin. T or F

Answer 51

true

Question 52

Secondary dentin is the result of insufficient mineralization. T or F

Answer 52

false

Question 53

Mantle dentin contains larger collagen fibers than circumpulpal dentin. T or F

Answer 53

true

Question 54

Odontoblastic processes taper in diameter, being largest near the dentinoenamel junction and smallest near the pulp. T or F

Answer 54

false

Question 55

Odontoblasts have a singular process when they first differentiate. T or F

Answer 55

false

Question 56

The junction between dentin and enamel is scalloped. T or F

Answer 56

true

Question 57

Odontoblast organelles are usually located within the cytoplasmic process. T or F

Answer 57

false

Question 58

Osteodentin is a form of reparative dentin that resembles cartilage. T or F

Answer 58

false

Question 59

Interglobular dentin is associated with vitamin B deficiency. T or F

Answer 59

false

Question 60

Secondary dentin is deposited more quickly than primary dentin. T or F

Answer 60

false

Question 61

Dentin is responsive to the environment. T or F

Answer 61

true

Question 62

Dead tracts develop when odontoblasts die from trauma or old age. T or F

Answer 62

true

Question 63

Dentinal tubules contain odontoblast processes, nerve terminals, and dentinal fluid. T or F

Answer 63

true

Question 64

The mesiodistal size difference between a primary molar and a permanent premolar is called the ____. a. leeway space b. furcation zone c. parietal plexus d. incisor liability

Answer 64

a. leeway space

Question 65

Which permanent tooth develops without a primary predecessor? a. Molar b. Incisor c. Canine d. Premolar

Answer 65

a. Molar

Question 66

Which structure(s) increase(s) the surface area of the osteoclast? a. Fibroblasts b. Ruffled border c. Periodontal fibers d. Epithelial diagram

Answer 66

b. Ruffled border

Question 67

Hard tissue resorption comprises which two phases? a. Mineral and collagen phases b. Prefunctional and functional phases c. Extracellular and intracellular phases d. Fibroblast eruptive and osteoclast functional phases

Answer 67

c. Extracellular and intracellular phases

Question 68

Which of the following is the origin of osteoclasts? a. Fibroblasts b. Monocytes c. Amino acids d. Root resorption

Answer 68

b. Monocytes

Question 69

Which type of dentin borders the pulp? a. Globular b. Predentin c. Reactionary d. Circumpulpal

Answer 69

b. Predentin

Question 70

Which type of dentin forms to protect and maintain the vitality of the pulp? a. Mantle b. Sclerotic c. Peritubular d. Reactionary

Answer 70

d. Reactionary