Deck 22: Eruption and Shedding of Teeth

Question 1

A fully formed impacted third molar is technically in the posteruptive stage because the roots are formed and this tooth would erupt if not impeded by another tooth.

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.

Answer 1

B
While it is True that this tooth would erupt if not impeded by another tooth, a fully formed impacted third molar is not in the posteruptive stage. This stage is defined by teeth coming into occlusion. Such a tooth is in the eruptive stage because the root is formed. The beginning of root formation defines the eruptive stage.

Question 2

Supra-eruption can cause serious problems in the replacement of the missing tooth because it makes it difficult to reestablish the normal occlusal plane.

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.

Answer 2

A
Supra-eruption, also called hypereruption, occurs when an opposing tooth is lost and the tooth continues to erupt beyond the occlusal plane. Note that this can occur at any phase of life and has serious occlusal and restorative implications.

Question 3

In eccentric growth the crown of a tooth grows in a perfectly symmetrical pattern because all areas grow proportionately as the crown enlarges.

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.

Answer 3

E
Eccentric growth is also called off-center growth because it is characterized by an asymmetrical growth pattern. As the crown enlarges, it grows more in one area than in another. Asymmetrical growth causes the center point of the crown to shift so the tooth appears to have moved.

Question 4

Each of the following has a role in tooth eruption EXCEPT for one. Which one is the EXCEPTION?

A) Root elongation
B) Periodontal ligament
C) Vascular pressures
D) Alveolar bone
E) All have a role in tooth eruption.

Question 5

The eruptive movement that pushes the crown of the tooth directly toward the surface is called eccentric movement. Excentric movement occurs during the eruptive stage.

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

Deciduous ankylosis occurs when

A) Cementum is fused to the alveolar bone.
B) Deciduous roots are fused to the permanent tooth crown.
C) Deciduous roots are intertwined, twisted, or fused.
D) There is no permanent tooth to cause deciduous root resorption.

Question 7

The successional lamina is seen only facial/buccal to the anterior primary teeth because the permanent anteriors erupt slightly lingual to their primary counterparts, while the permanent posterior teeth lie below the primary and erupt through their established alveolus.

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 8

Supra-eruption is

A) Complete eruption
B) The last phase of the posteruptive stage
C) A tooth with an unusually long crown or root
D) A tooth that erupts beyond the occlusal plane

Question 9

Active tooth eruption refers to the emergence of a crown into the oral cavity. This eruptive process is usually divided into the pre-eruptive and posteruptive stages.

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

An ankylosed deciduous tooth will prevent the eruption of a permanent tooth because the alveolar crest of the bone fuses in the cervical area with the dentin of a resorbing root.

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 11

Tooth eruption is dependent upon the dental sac because this structure plays a role in the formation of cementum, the periodontal ligament, and alveolar bone.

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 12

Each of the following typically occur with retained root tips EXCEPT one. Which one is the EXCEPTION?

A) Cyst formation
B) Root tip resorption
C) Root tip eruption
D) Malaligned teeth

Question 13

As the permanent teeth become surrounded by bone, the successional lamina forms small openings in the alveolar bone, known as

A) Pre-eruptive foramina
B) Successional lamina buds
C) Gubernacular canals
D) Bony crypt grooves

Question 14

Vascular pressures in the periodontium seem to disrupt eruption because the pulsating blood pressures interfere with cellular activity.

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

During the eruptive stage the reduced enamel epithelium fuses with the dental follicle to create an eruptive force. The eruptive stage continues until the erupting teeth meet the opposing arch.

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

During the pre-eruptive stage bone is in a U-shaped crypt. When the root forms, osteoclasts may deepen the crypt.

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

In the pre-eruptive stage, all of the following occur EXCEPT one. Which one is the EXCEPTION?

A) Asymmetrical crown growth
B) Slight crown movement
C) Early root formation
D) Filling in of tooth socket with bone

Question 18

The primary tooth is able to erupt because the gubernacular canal breaks down the bone between the tooth and the surface 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 19

It is possible for a child to have a deciduous tooth and its permanent counterpart at the same time. This can occur when the permanent teeth erupt labially.

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

Which structure acts as a "shock absorber" during the eruption process?

A) Alveolar bone
B) Dental pulp
C) Cementum
D) Periodontal ligament
E) All of the above

Question 21

Root elongation is the main factor in the tooth's eruption into the oral cavity.

Question 22

If Hertwig's root sheath is destroyed the tooth will not erupt.

Question 23

All of the following are characteristic of the posteruptive stage EXCEPT one. Which one is the EXCEPTION?

A) Root development
B) Occlusal wear
C) Mesial drift
D) Supra-eruption

Question 24

Which of the following are necessary for the tooth eruption to occur (select all that apply)?

A) The presence of the outer layers of the enamel organ
B) Osteoclastic activity
C) The rhythmic cycle of bone development
D) The absence of the dental sac
E) The presence of the dental follicle

Question 25

The united epithelium is broken down by enzymatic action of Hertwig's root sheath. Upon breakdown of this epithelium the tooth emerges into the oral cavity.

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 26

The reduced enamel epithelium and the oral epithelium fuse into the united oral epithelium.

Question 27

If a root is damaged during formation, which of the following would occur?

A) Tooth eruption ceases
B) Tooth eruption continues
C) Root decay
D) Ankylosis

Question 28

In spatial movement, the crown develops while the tooth socket fills in with bone.

Question 29

The direction of tooth eruption is facial and apical.