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.

Accepted Answer

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

Accepted Answer

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.

Accepted Answer

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.

Accepted Answer

Both the periodontal ligament embedded in cementum and the periodontal fibers surrounded by alveolar bone are known as Sharpey's fibers. Cementocytes are cementoblasts that become entrapped in cellular cementum.

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.

Accepted Answer

Lamina dura is a radiographic term denoting the cribriform plate and bundle bone. Alveolar bone or alveolar process by definition is the bone of the upper or lower jaw that comprises the sockets for the teeth. Bone is mesodermal in origin.

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.

Accepted Answer

Bone reacts more favorably to stress than cementum because bone has a much better blood supply and therefore a higher metabolic rate than cementum.

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.

Accepted Answer

The metabolic rate of bone is much higher than that of cementum. Bone has the ability to remodel, which is illustrated by orthodontic movement of teeth. As pressure is placed upon a tooth, bone is resorbed by osteoclasts. New bone is formed by osteoblasts. Cementum does not undergo such a vital process.

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

Accepted Answer

The circular gingival fibers are classified as gingival fibers. They run from the cementum into the free and attached gingival areas and tend to support the gingiva. The remaining selections are groups of alveolodental fibers that run in various directions from the cementum to the alveolar bone.

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.

Accepted Answer

The epithelial root sheath and epithelial diaphragm guide the shape and the number of roots. The manner in which the epithelial diaphragm grows inward determines whether a tooth will have one, two, or three roots. The vertical length of the root is controlled by growth of the epithelial root sheath.

Question 10

The main fiber group for resisting occlusal stress is the
A) Interradicular
B) Apical
C) Horizontal
D) Oblique

Accepted Answer

The oblique group of alveolodental fibers resist occlusal stress. This group runs from the cementum coronally into the alveolar bone. The remaining selections, each a component of the alveolodental fiber group, run from cementum to alveolar bone.

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

Accepted Answer

Epithelial rests of Malassez, simply called epithelial rest cells, are cells that remain in the dentin following breakup of the root sheath. The remaining selections can occur during this period due to disruption or inconsistencies of the deterioration of the epithelial root sheath.

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

Accepted Answer

The lamina dura is a radiographic landmark. It typically appears as a thin radiopaque (white) line surrounding the periodontal ligament. A thickened lamina dura in one or more teeth is frequently an indication of occlusal trauma.

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.

Accepted Answer

Sharpey's fibers are the ends of the periodontal ligament and are embedded in cementum lying perpendicular to its surface.

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.

Accepted Answer

While osteoclasts are more adept at resorbing bone, their multinucleated cellular structure enables them to also resorb cementum and dentin.

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.

Accepted Answer

During early root formation the point where the OEE meets the IEE, known as the cervical loop, is located at the deepest part of the enamel organ.

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.

Accepted Answer

As the root sheath grows from the cervical line into deeper connective tissue, cells of the dental papilla become odontoblasts and begin to secrete dentin. Cellular influences cause the root sheath to break up and separate from this newly formed dentinal surface. During this process some of the dental sac cells begin to change into cementoblasts and begin to form cementum. This cementum is laid down against the previously formed dentin and establishes the dentinocemental junction (DEJ).

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.

Accepted Answer

There are two types of cementum, acellular and cellular. In the acellular type, cementoblasts remain on the surface of the newly formed cementum. In the cellular type, cells become entrapped as they secrete matrix. These trapped cells are called cementocytes.

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.

Accepted Answer

In about 60% of the population cementum overlaps the enamel. In 30% the cementum meets the enamel at a sharp junction, and in the remaining 10% of the population the cementum and enamel do not meet, thus leaving exposed dentin at the cervical line.

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.

Accepted Answer

The periosteum of the bone that forms the tooth socket is considered atypical because it contains holes that enable the passage of blood vessels. The periosteum is a membrane that lines the outer surface of all bones, except at the joints of long bones.

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.

Accepted Answer

Cementoblasts are cells that produce cementum. Although cementum does not have the higher metabolic function and remodeling capabilities of bone, it does have limited ability to change in response to stress.

Quiz 21: Root Formation and Attachment Apparatus

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.

The compact bone that is perforated in many places is the

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

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.

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.

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

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

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

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.

The main fiber group for resisting occlusal stress is the

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

Which of the following indicates occlusal trauma?

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

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

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.

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) .

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

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

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.

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