Deck 19: Dental Lamina and Enamel Organ

Question 1

The enamel organ originates from the

A) Endoderm
B) Ectoderm
C) Mesoderm
D) Ameloblasts

Answer 1

B
Cells of the enamel organ originate from ectodermal tissue. Note that as the enamel organ develops, the stellate reticulum forms between the inner enamel epithelium (IEE) and the outer enamel epithelium (OEE). Stellate reticulum is also ectodermal in origin.

Question 2

The cap stage begins when the concavity of the tooth buds becomes slightly concave.

Answer 2

True
As tooth buds develop they seem to stretch from the dental lamina, with the deepest parts becoming slightly concave. It is at this point that the developing enamel organ progresses from the bud stage to the cap stage.

Question 3

The clefting that occurs in the thickened vestibular lamina eventually becomes a mucogingival groove. The vestibular lamina is a thickening of oral epithelium in a lingual direction.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Answer 3

C
The vestibular lamina forms the area of the mucobuccal or mucolabial fold in the future vestibule. As the epithelium of the vestibular thickens in a facial or buccal direction, a clefting or splitting occurs. This is a key event in the formation of the fold within the vestibule. Without these events the vestibule would end at the level of the alveolar ridge.

Question 4

Without thickening of the vestibular lamina in an occlusal direction the vestibule would not exist because clefting or splitting of the epithelium would not occur.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct, but the reason is NOT correct.
D) The statement is NOT correct, but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 5

The cells between the dental papilla and the outer enamel epithelium (OEE) compose the stellate reticulum. Originating from deep layers of the oral epithelium, cells of the stellate reticulum are mesenchymal in origin.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Question 6

Premolars are successional because they develop from a posterior growth of the dental, or general, lamina.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct, but the reason is NOT correct.
D) The statement is NOT correct, but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 7

The earliest signs of tooth development are seen during the tenth week in utero.

Question 8

The dental papilla is first seen in the _____ stage.

A) Early bud
B) Late bud
C) Cap
D) Bell

Question 9

At about the sixth embryonic week, there is a continued thickening in the dental lamina. These localized thickenings correspond to the positions of the twenty teeth of the future primary dentition.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Question 10

The outermost part of the structure of the cap stage is the outer enamel epithelium (OEE). This tissue, a continuation of the basal layer of oral epithelium, is composed of predominately pyramidal and conical-shaped cells.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Question 11

The stratum intermedium develops during which stage?

A) Early bud
B) Late bud
C) Cap
D) Bell

Question 12

The cells of the outer enamel epithelium (OEE) are indirectly responsible for enamel formation because they elongate and become ameloblasts.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct, but the reason is NOT correct.
D) The statement is NOT correct, but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 13

The successional lamina forms all permanent teeth EXCEPT for one type. Which type is the EXCEPTION?

A) Incisors
B) Canines
C) Premolars
D) Molars

Question 14

Skin, hair, enamel, and cementum can be adversely affected by ectodermal dysplasia because this condition causes poor development of structures arising from ectoderm.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct, but the reason is NOT correct.
D) The statement is NOT correct, but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 15

Cells of the outer enamel organ (OEE) constrict and morph into ameloblasts. Stellate reticulum, in conjunction with ameloblasts, is responsible for enamel formation.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Question 16

The dental sac is composed of several layers of flat mesodermal cells that partially surround the dental papilla and the enamel organ. The dental sac is another name for the dental lamina.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Question 17

The cells of the inner enamel epithelium (IEE) are structurally similar to the cells of the outer enamel epithelium (OEE) because they both originate from the basal layer of the oral epithelium.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct, but the reason is NOT correct.
D) The statement is NOT correct, but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 18

Each of the following statements accurately describes aspects of the development of the enamel organ EXCEPT one. Which one is the EXCEPTION?

A) Buds from the dental lamina project into deeper underlying connective tissue.
B) The bud stage is the first stage in the development of the enamel organ.
C) The enamel organ will eventually form the enamel and cementum of teeth.
D) Cells in the middle of the buds come from outer layers of oral epithelium.
E) Cells in the periphery of the buds come from deep layers of the oral epithelium.

Question 19

The appearance of the stratum intermedium differentiates the cap stage from the bell stage. The stratum epithelium, the fourth layer of epithelium, lies between the inner enamel epithelium and the outer enamel epithelium.

A) Both statements are true.
B) The first statement is true; the second is false.
C) The first statement is false; the second is true.
D) Both statements are false.

Question 20

The vestibular lamina forms in a lingual direction from the dental lamina.

Question 21

The dental lamina thickens first at the anterior midline.

Question 22

The first stage of development of the enamel organ is the cap stage.

Question 23

The permanent molars develop from successional lamina.