Deck 21: Root Formation and Attachment Apparatus

Question 1

Root formation begins at the cementoenamel junction (CEJ) and proceeds to the root apex. During this process the epithelial root sheath becomes the epithelial diaphragm.

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 1

B
During the process of root formation both the epithelial root sheath and the epithelial diaphragm retain their individual identities. While they work in conjunction, they perform separate functions.

Question 2

The compact bone that is perforated in many places is the

A) Cortical plate
B) Cribriform plate
C) Bundle bone
D) Cancellous bone

Answer 2

B
The cribriform plate, also called alveolar bone proper, forms the tooth socket. Like the cortical plate on the buccal or lingual surfaces, the cribriform plate is a compact bone. However, the cribriform plate has an atypical periosteum with numerous holes that allow for the passage of blood vessels.

Question 3

Root sheath cells that remain in the periodontal space are called epithelial rest cells. If they later divide they form epithelial rests of Malassez.

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

B
Root sheath cells that remain in the periodontal space are called epithelial rest cells, or more formally, epithelial rests of Malassez. If they later divide they may lead to formation of periodontal cysts.

Question 4

The parts of the periodontal ligament embedded in cementum are known as cementocytes. The periodontal fibers surrounded by alveolar bone on the other side of the tooth socket are known as Sharpey's fibers.

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 5

By definition, alveolar bone or alveolar process is the bone of the upper or lower jaw that comprises the lamina dura for the teeth. Bone originates from the mesoderm.

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

Bone reacts more favorably to stress than cementum because bone has a higher inorganic content.

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

Bone undergoes a remodeling process whereas cementum does not because the metabolic rate of bone is lower than that of cementum.

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

Each of the following are classified as alveolodental fibers EXCEPT one. Which one is the EXCEPTION?

A) Alveolar crest fibers
B) Horizontal fibers
C) Circular gingival fibers
D) Oblique fibers
E) Apical fibers

Question 9

During the bell stage of root development the cervical loop is located at the deepest part of the enamel organ. The cervical loop and the epithelial diaphragm guide the shape and number of roots.

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 main fiber group for resisting occlusal stress is the

A) Interradicular
B) Apical
C) Horizontal
D) Oblique

Question 11

Each of the following defects can occur during or after the breakup of the epithelial root sheath EXCEPT one. Which one is the EXCEPTION?

A) Periodontal cysts
B) Accessory root canals
C) Hypercementosis
D) Enamel pearls
E) Epithelial rests of Malassez

Question 12

Which of the following indicates occlusal trauma?

A) A thickened lamina dura
B) A layer of spongy bone
C) Pointed (or pyramidal-shaped) interproximal alveolar bone
D) Sharpey's fibers in the alveolar bone

Question 13

Sharpey's fibers are part of the cementum. They are embedded in alveolar bone.

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 14

Osteoclasts can resorb bone, cementum, and dentin because their ability to resorb tissues is not specific to any one of these tissues.

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

Immediately prior to root formation, the point where layers of outer enamel epithelium (OEE) meets inner enamel epithelium (IEE) is known as the cervical loop. This point is located at the most superficial point of the enamel organ.

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

Development of the dentinocemental junction (DCJ) involves newly formed odontoblasts and cementoblasts. The root sheath must separate from the dentinal surface to establish the dentinocemental junction (DCJ).

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

Acellular cementum contains trapped cementoblasts because they remain in the matrix after secretion.

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

Which is the most common relationship of the cementum to the enamel?

A) Cementum meets the enamel at a definite point or junction.
B) The cementum and enamel do not meet, exposing a portion of dentin.
C) The cementum overlaps the enamel.
D) The enamel overlaps the cementum.

Question 19

The alveolar bone that forms the tooth socket has a normal periosteum because this bone contains numerous holes that allow for passage of blood vessels.

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 20

The outer layer of cementum is lined with cementoblasts. Cementum has limited ability to form throughout adulthood.

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 21

In the two cross-sectional views of alveolar bone depicted below, structure "c" illustrates the

A) Spongy bone
B) Cribriform plate
C) Cortical plate

Question 22

Root formation begins after the full crown has been calcified.

Question 23

The organic components in cementum are (select all that apply):

A) Mucopolysaccharides
B) Hydroxyapatite crystals
C) Collagen fibers
D) Mineral salts
E) Water

Question 24

The epithelial diaphragm is parallel to the root sheath.

Question 25

The transseptal fibers run from the cementum into the free and attached gingival area. The alveolodental fibers run from the cementum to the alveolar bone.

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 cortical plate is typically compact bone with an atypical periosteum.

Question 27

Enamel pearls (select all that apply):

A) Are formed by cementocytes
B) Are usually found in root furcations
C) Are small elevators of enamel
D) Dissolve after root completion
E) Often cause periodontal cysts

Question 28

Which of the following sensations can the nerves of the periodontal fibers transmit (select all that apply)?

A) Pain
B) Heat
C) Cold
D) Pressure
E)Not of above

Question 29

When a tooth is moved orthodontically, all of the following should occur EXCEPT one. Which one is the EXCEPTION?

A) Tension on periodontal fibers
B) Bone resorption
C) Bone deposition
D) Cementum regeneration

Question 30

In the two cross-sectional views of alveolar bone depicted below, structure "b" illustrates the

A) Cribriform plate
B) Spongy bone
C) Cortical plate

Question 31

The periodontal ligament develops from the mesodermal cells of the dental sac.

Question 32

In the two cross-sectional views of alveolar bone depicted below, structure "a" illustrates the

A) Cribriform plate
B) Cortical plate
C) Spongy bone

Question 33

The epithelial root sheath is between the dental papilla and the dental sac in early root development.