Deck 7: Enamel

Question 1

Which part of the enamel rod is most sensitive to demineralization?

A) Tail
B) Core
C) Head
D) Sheath

Answer 1

B

Question 2

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 2

D

Question 3

An enamel ______ houses a small extension of a living odontoblast.

A) rod
B) tuft
C) spindle
D) lamellae

Answer 3

C

Question 4

Enamel is composed of ______ hydroxyapatite.

A) 26%
B) 53%
C) 90%
D) 96%

Question 5

Two ameloblast cells form the enamel rod

A) head.
B) neck.
C) body.
D) tail.

Question 6

Which type of enamel contains many tiny spaces stained with pigment?

A) Gnarled
B) Prenatal
C) Postnatal
D) Prismless

Question 7

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.

Question 8

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.

Question 9

Ameloblasts deposit 4 µm of enamel rods daily.

Question 10

Enamel is approximately ______ thick at the occlusal or incisal surface.

A) 1 µm
B) 9 µm
C) 2.5 mm
D) 4.5 mm

Question 11

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

Question 12

The organic component of enamel is called

A) hydroxyapatite.
B) enamelin.
C) gnarled enamel.
D) perikymata.

Question 13

Ameloblasts travel along parallel paths to produce straight enamel rods.

Question 14

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.

Question 15

Ameloblasts produce _______ as they migrate.

A) cementoid
B) enamel rods
C) epithelial rests
D) dentinal tubules

Question 16

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

Question 17

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

Question 18

Which of the following does not facilitate the spread of dental caries?

A) Enamel tufts
B) Enamel lamellae
C) Incremental lines
D) Prismless enamel

Question 19

The surface of the enamel rod is called the rod

A) margin.
B) periphery.
C) sheath.
D) core.

Question 20

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.

Question 21

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

Question 22

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

Question 23

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

Question 24

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

Question 25

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

Question 26

Each enamel rod is formed by a single ameloblast.

Question 27

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

Question 28

Enamel is an impermeable tissue.

Question 29

Etching the surface of enamel stimulates remineralization.

Question 30

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

Question 31

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

Question 32

Enamel varies in density and hardness.