Final (Chs 13-14)

Question 1

The most common cell type in connective tissue such as pulp is the:

a. endothelial cell.
b. fibroblast.
c. white blood cell.
d. odontoblast.

Answer 1

b. fibroblast.

As in all forms of connective tissue, the fibroblasts are the largest group of cells in the pulp. The odontoblasts are the second largest group of cells in the pulp, but only their cell bodies are located in the pulp. The pulp contains white blood cells in its tissue and vascular supply, but levels are normally low, unless the cells are ready to be triggered by an inflammatory or immune reaction. Endothelial cells line the blood vessels within the pulp.

Question 2

Which of the following is the only sensation perceived by the brain from the pulp’s sensory nerves?

a. taste
b. pain
c. temperature
d. pressure

Answer 2

b. pain

The brain perceives all sensations directed to the pulp as sensations of pain. Therefore, changes in temperature, vibrations, and chemical changes that affect the pulp or dentin by way of the pulp’s nerves are perceived only as painful stimuli.

Question 3

During cavity preparation of a tooth, care must be taken to preserve the:

a. enamel rod fluid.
b. support of the dentinal tubules.
c. cemental vascularity.
d. vitality of the pulp.

Answer 3

d. vitality of the pulp.

Dental professionals must do their utmost to prevent injury and preserve the vitality of the pulp during preventive and restorative procedures. Such iatrogenic injury to the pulp can result from the heat or vibrations emitted by dental handpiece during cavity preparation.

Question 4

Which of the following pulp structures is formed when Hertwig epithelial root sheath encounters a blood vessel?

a. pulp horn
b. pulp chamber
c. apical foramen
d. accessory canal

Answer 4

d. accessory canal

Accessory canals form when Hertwig epithelial root sheath encounters a blood vessel during root formation. Root structure then forms around the blood vessel, forming the accessory canal. The coronal pulp is located in the crown of the tooth. Smaller extensions of coronal pulp into the cusps of posterior teeth form the pulp horns. The large mass of pulp is contained within the pulp chamber of the tooth. The apical foramen is the opening from the pulp into the surrounding periodontal ligament near each apex of the tooth.

Question 5

During tooth development, both the pulp and the dentin in the mature tooth are products of the:

a. dental papilla.
b. enamel organ.
c. dental sac.
d. epithelium.

Answer 5

a. dental papilla.

Dentin and pulp tissue have similar embryologic backgrounds because both are originally derived from the dental papilla of the tooth germ during tooth development.

Question 6

Secondary dentin usually forms within the tooth:

a. after the completion of the apical foramen.
b. before the completion of the apical foramen.
c. nearest to the dentinoenamel junction.
d. in response to tooth trauma.

Answer 6

a. after the completion of the apical foramen.

Secondary dentin is formed after the completion of the apical foramen(s) and continues to form throughout the life of the tooth. Primary dentin is formed in a tooth before the completion of the apical foramen(s) of the root, which is the opening in the root’s pulp canal. Mantle dentin is the first predentin that forms near the dentinoenamel junction. Tertiary dentin forms quickly in localized regions in response to a localized tooth trauma to the exposed dentin.

Question 7

Dentin in a mature tooth is on the average about ______ mineralized by weight.

a. 50%
b. 65%
c. 70%
d. 96%

Answer 7

c. 70%

Mature dentin is by weight 70% inorganic material or mineralized. The alveolar process is by weight 50% inorganic material. Mature cementum is by weight 65% inorganic material. Mature enamel is by weight 96% inorganic material.

Question 8

Which of the following terms associated with dentin can be used to correctly describe the type that makes up the largest part of the tooth’s dentin?

a. Tomes granular layer
b. mantle dentin
c. circumpulpal dentin
d. interglobular dentin

Answer 8

c. circumpulpal dentin

Deep to the mantle dentin is the layer of dentin around the outer wall of pulp, the circumpulpal dentin, which makes up the bulk of the dentin in a tooth. Tomes granular layer is most often found in the peripheral part of dentin beneath the root’s cementum. Mantle dentin is the first predentin that forms near the dentinoenamel junction. Interglobular dentin is found in those areas where only primary mineralization has occurred within the predentin, and the globules of dentin do not fuse completely and appear as dark arclike areas in a stained section of dentin.

Question 9

In which location is the cell body of the odontoblast found in a mature healthy erupted tooth?

a. along the dentinoenamel junction
b. along the outer pulpal wall
c. near the dentinocemental junction
d. near the pulpal core

Answer 9

b. along the outer pulpal wall

The odontoblasts are located only along the outer pulpal wall. Only their cell bodies are located in the pulp.

Question 10

With increased age, the pulp tissue can become:

a. displaced by primary dentin.
b. increasingly fibrotic.
c. filled with cementicles.
d. increasingly cartilaginous.

Answer 10

b. increasingly fibrotic.

With increased age, the pulp undergoes a decrease in intercellular substance, water, and cells as it fills with an increased amount of collagen fibers and thus becomes fibrotic.

Question 11

Predentin is the initial material laid down by the:

a. odontoblasts.
b. ameloblasts.
c. preameloblasts.
d. odontoclasts.

Answer 11

a. odontoblasts.

Predentin is a mesenchymal product consisting of nonmineralized collagen fibers produced by the odontoblasts. Ameloblasts form from preameloblasts and then later produce enamel. Odontoclasts are active during eruption, removing parts of the primary tooth.

Question 12

The dark, arc-like areas in histologic sections of a tooth are what type of dentin?

a. Tomes granular layer
b. mantle dentin
c. circumpulpal dentin
d. interglobular dentin

Answer 12

d. interglobular dentin

The dark, arclike areas in a stained histologic section in a tooth are considered interglobular dentin. In these areas, only primary mineralization has occurred within the predentin, and the globules of dentin do not fuse completely. Tomes granular layer is most often found in the peripheral part of dentin beneath the root’s cementum. Mantle dentin is the first predentin that forms near the dentinoenamel junction. Deep to the mantle dentin is the layer of dentin around the outer wall of pulp, the circumpulpal dentin, which makes up the bulk of the dentin in a tooth.

Question 13

Which of the following includes the tissue fluid surrounding the cell membrane of the odontoblast?

a. lymph
b. gingival crevicular fluid
c. dentinal fluid
d. synovial fluid

Answer 13

c. dentinal fluid

The dentinal fluid in the tubule includes the tissue fluid surrounding the cell membrane of the odontoblast. The lymph is found within the lymphatic system. The gingival crevicular fluid is located within the gingival sulcus. The synovial fluid is found within the temporomandibular joint, surrounding the disc of the joint.

Question 14

Which of the following are a number of adjoining parallel imbrication lines that are present in stained dentin?

a. lines of Retzius
b. reversal lines
c. arrest lines
d. contour lines of Owen

Answer 14

d. contour lines of Owen

The contour lines of Owen are a number of adjoining parallel imbrication lines that are also present in a stained section of dentin. These specific imbrication lines demonstrate a disturbance in body metabolism that affects the odontoblasts by altering their formation efforts, and they tend to appear together as a series of dark bands. The lines of Retzius are incremental lines noted in stained enamel. Both reversal lines and arrest lines are stained lines noted in both cementum and repair due to repair and apposition of the hard tissue, respectively.

Question 15

Lateral pulp canals within the pulp chamber extend:

a. from pulp tissue to the periodontal ligament.
b. vertically toward the cementum.
c. between two pulp canals, as a bridge.
d. from the chamber, parallel to another canal.

Answer 15

a. from pulp tissue to the periodontal ligament.

Accessory canals may also be associated with the pulp and are extra openings from the pulp to the periodontal ligament Accessory canals are also called lateral canals, because they are usually located on the lateral surface of the roots of the teeth, but this is not always the case because they can be found anywhere along the root surface.

Question 16

Dentin in the mature tooth is produced as a result of secretion by:

a. cementoblasts.
b. fibroblasts.
c. osteoblasts.
d. odontoblasts.

Answer 16

d. odontoblasts

Apposition of dentin by odontoblasts, unlike enamel, occurs throughout the life of the tooth, filling in the pulp chamber of both the crown and root.

Question 17

What are the smaller extensions of coronal pulp into the cusps of posterior teeth termed?

a. accessory canals
b. lateral canals
c. pulp horns
d. pulp canals

Answer 17

c. pulp horns

The coronal pulp is located in the crown of the tooth. Smaller extensions of coronal pulp into the cusps of posterior teeth form the pulp horns. Accessory canals may also be associated with the pulp and are extra openings from the pulp to the periodontal ligament; accessory canals are also called lateral canals. The radicular pulp, or root pulp, is the part of the pulp located in the root of the tooth; it is also called the pulp canal by patients.

Question 18

Which is the most common type of nerves associated with the pulp in a mature erupted tooth?

a. myelinated
b. unmyelinated
c. myelinated and unmyelinated are in equal numbers
d. dead ones

Answer 18

b. unmyelinated

Two types of nerves are associated with the pulp, which includes mainly unmyelinated nerves (70% to 80%) and in lesser amounts, myelinated nerves (20% to 30%).

Question 19

Which of the following zones in pulp is closest to the dentin?

a. odontoblastic layer
b. cell-rich zone
c. pulpal core
d. cell-free zone

Answer 19

a. odontoblastic layer

The first zone of pulp closest to the dentin is the odontoblastic layer. The next zone, nearest to the odontoblastic layer, inward from the dentin, is considered the cell-free zone. The next zone, nearest to the odontoblastic layer, inward from the dentin, is considered the cell-free zone. The final zone of pulp is the pulpal core, which is in the center of the pulp chamber.

Question 20

Which zone in the pulp contains a nerve and capillary plexus?

a. odontoblastic layer
b. cell-rich zone
c. pulpal core
d. cell-free zone

Answer 20

b. cell-rich zone

A nerve and capillary plexus are also located in the cell-free zone of the pulp. The odontoblastic zone consists of a layer of odontoblasts. The cell-rich zone has an increased density of cells compared with the cell-free zone but still does not contain as many cells as the odontoblastic layer. This zone also has a more extensive vascular supply than does the cell-free zone. The pulpal core, which is in the center of the pulp chamber, consists of many cells and an extensive vascular supply; except for its location, it is very similar to the cell-rich zone.

Question 21

Which of the following statements is correct when considering accessory canals?

a. Teeth have a standard number.
b. Radiographs always indicate the number and position.
c. Gingival recession may expose the opening.
d. They are examined by placing radiolucent materials.

Answer 21

c. Gingival recession may expose the opening.

Gingival recession may expose the opening of an accessory canal. Teeth have a variable number of these canals. Radiographs do not always indicate the number or position of these canals, unless they are examined with instruments using radiopaque materials.

Question 22

Which of the following is not associated with dentinal hypersensitivity?

a. enamel and cementum do not meet
b. dentin exposed due to caries process
c. blocking dentinal tubules
d. branching of dentinal tubules

Answer 22

c. blocking dentinal tubules

Dentinal hypersensitivity can be treated somewhat successfully with solutions applied either by professionals or within over-the-counter dentifrices available to patients; these desensitizing agents temporarily block the exposed open ends of the dentinal tubules. When dentin is exposed as a result of caries, the open dentinal tubules may be painful, causing dentinal hypersensitivity. However, many times it is the microscopic anatomy of the tooth that is the culprit; the enamel and cementum do not meet, leaving a gap with dentin exposed. Branching of the dentinal tubules containing the live odontoblastic processes throughout dentin adds to the overall level of exposure.

Question 23

The resorption process within the dentin can result in a clinically presentation of a:

a. silver-hued tooth
b. pulp with stones
c. pinkish crown color
d. carious tooth

Answer 23

c. pinkish crown color

Dentin can become resorbed in permanent teeth, but the cause is idiopathic and can involve either an internal or external resorption process. It can be noted radiographically, but it is hard to discern between the two processes. In contrast, when the process begins on the external surface of the root and then penetrates through the cementum into dentin, it can lead to a pinkish crown color noted clinically from the granulation tissue seen beneath the translucent enamel.

Question 24

What type of dentin occurs when odontoblasts in the area of the traumatized tubules may perish because of the injury, but neighboring undifferentiated mesenchymal cells of the pulp can move to the area and become odontoblasts?

a. reparative dentin
b. reactive dentin
c. sclerotic dentin
d. mantle dentin

Answer 24

a. reparative dentin

Odontoblasts in the area of the traumatized tubules may perish because of the injury, but neighboring undifferentiated mesenchymal cells of the pulp can move to the area and become odontoblasts, forming a type of tertiary dentin, reparative dentin. If the tertiary dentin is formed by existing odontoblasts, it is considered to be reactive dentin. A certain type of tertiary dentin, sclerotic dentin occurs when the odontoblastic processes die and leave the dentinal tubules vacant. Mantle dentin is the first predentin that forms.

Question 25

In what direction do the imbrication lines of von Ebner run? a. at 45 degrees to the DEJ b. at 90 degrees to the dentinal tubules c. at 45 degrees to the inner pulpal wall d. at 90 degrees to the periodontal ligament

Answer 25

b. at 90 degrees to the dentinal tubules The imbrication lines of von Ebner are incremental lines or bands that stain darkly in a section of dentin. They run at 90 degrees to the dentinal tubules.

Question 26

Sharpey's fibers are located in which of the following types of dental tissue? a. enamel b. dentin c. cementum d. pulp

Answer 26

**cementum** Sharpey fibers are a part of the collagen fibers from the periodontal ligament that are each partially inserted into the outer part of the cementum at 90 degrees or perpendicular to the cemental surface (as well as the alveolar process on their other end) as they are inserted on the other end, the alveolar process.

Question 27

which of the following types of dental tissue provides the vascular nutrition for the tooth's cementum? a. dentin b. epithelial cells c. periodontal ligament d. alveolar process

Answer 27

c. periodontal ligament The canals of the cementocytes are oriented toward the periodontal ligament and contain cementocytic processes that exist to diffuse nutrients from the ligament because it is vascularized.

Question 28

which of the following terms correctly describes the alveolar bone proper? a. lamina propria b. cancellous bone c. mucoperiosteum d. cribriform plate

Answer 28

d. cribriform plate * The alveolar bone proper makes up the lining of the tooth socket or alveolus. Although the alveolar bone proper is composed of compact bone, it may be called the cribriform plate because it contains numerous holes where Volkmann canals with their nerves and blood vessels pass from the alveolar process into the periodontal ligament. The lamina propria is the connective tissue component of the oral mucosa. A mucoperiosteum is a combined structure consisting of a mucous membrane, in the case of the oral cavity, the epithelium and lamina propria of the oral mucosa, with the periosteum of bone. The trabecular bone consists of cancellous bone or spongy bone that is located between the alveolar bone proper and the plates of cortical bone.*

Question 29

the rests of Malassez are correctly described as: a. remnants of the outer enamel epithelium b. similar to incremental growth limes in dentin c. remnants of Hertwig root sheath d. similar to the incremental growth lines in enamel

Answer 29

c. remnants of Hertwig sheath The epithelial rests of Malassez, which represent groups of epithelial cells, are stranded in mature periodontal ligament after the disintegration of Hertwig epithelial root sheath during the formation of the root.

Question 30

on radiographs, the periodontal ligament appears as a: a. radiopaque line covering the alveolar bone proper b. lamina dura surrounding the alveolus c. radiolucent space surrounding the alveolus d. spongy material between the alveolus and alveolar bone peoper

Answer 30

c.radiolucent space surrounding the alveolus The periodontal ligament appears on radiographs as a radiolucent area (or darker) located between the denser radiopaque (or lighter) lamina dura of the alveolar bone proper and the similar radiopaque (or lighter) cementum.

Question 31

which of the following situations can be present at the cementoenamel junction in a mature tooth? a. cementum overlaps enamel b. enamel overlaps cementum c. dentin overlaps enamel d. pulp overlaps cementum or dentin

Answer 31

a. cementum overlaps enamel Three possible types of transitional interfaces may be present at the cementoenamel junction. The cementum may overlap the enamel at the cementoenamel junction. The cementum and enamel may meet end to end, presenting no problems for either the clinician or patient. Another possible interface at the cementoenamel junction is that a gap may exist between the cementum and enamel, exposing dentin.

Question 32

which of the following fiber groups is a part of the alveodental ligament on a single- rooted adult tooth? a. circular ligamnet b. interdental ligament gingival fiber group d. apical group

Answer 32

d. apical group The main principal fiber group is the alveolodental ligament, which consists of five fiber subgroups: alveolar crest, horizontal, oblique, apical, and interradicular on multirooted teeth. The circular ligament is part of the gingival fiber groups and some consider these ligaments as a group to be part of the principal fibers but separate from the alveodental ligament. Another principal fiber other than the alveolodental ligament is the interdental ligament.

Question 33

which of the following statements concerning the oblique group of the periodontal ligament is correct? a. part of the gingival fiber group b. found only in multi-rooted teeth c. resists intrusive forces to the tooth d. resists tilting forces to the tooth

Answer 33

c. resists intrusive forces to the tooth The function of the oblique group as part of the alveodental ligament of the periodontal ligament is to resist intrusive forces, which try to push the tooth inward, as well as rotational forces; it is found on both single and multirooted teeth.

Question 34

which part of both of the jaws contains cancellous bone? a. alveolar bone proper b. cortical bone c. interdental septum d. alveolar crest

Answer 34

c. interdental septum The interdental septum consists of both the compact bone of the alveolar bone proper and cancellous bone of the trabecular bone. The alveolar bone proper is composed of compact bone. The cortical bone consists of a plate of compact bone on both the facial and lingual surfaces of the alveolar process. The alveolar crest is the most cervical rim of the alveolar bone proper.

Question 35

the most common type of connective tissue fiber in the periodontal ligament is which of the following fiber groups? a. collagen b. elastic c. oxytalan d. collagen and elastic fibers

Answer 35

a. collagen All the fibers in the periodontal ligament are collagen in structure.

Question 36

which of these fiber groups does not have any cemental insertion? a. interdental ligament b. circular ligament c. alveodental ligament d. Interradicular group

Answer 36

b. circular ligament The circular ligament encircles the tooth, as shown on a cross section of a tooth, interlacing with the other gingival fiber subgroups. Thus, it has no cemental insertion. The interdental ligament and alveodental ligament, which the interradicular group is part of on multirooted teeth, both have cemental insertions.

Question 37

the periodontal ligament directly forms from which part of the developing tooth germ? a. enamel organ b. dental papilla c. dental sac d. both enamel organ and dental papilla

Answer 37

c. dental sac Similar to the alveolar process, the periodontal ligament develops from the dental sac of the tooth germ. The enamel organ gives rise to the enamel and the dental papilla gives rise to the dentin and pulp of the tooth.

Question 38

the cementoblasts originate during tooth development from which of the following embryonic structures? a. enamel organ b. dental papilla c. dental sac d. both enamel organ and dental papilla

Answer 38

c. dental sac Cementum and its cells, the cementoblasts, develop from the dental sac and form on the root after the disintegration of Hertwig epithelial root sheath. The dental papilla gives rise to the dentin and its odontoblasts as well as the pulp and its fibroblasts. The enamel organ gives rise to the enamel and its ameloblasts.

Question 39

the alveolar bone proper of the jaws in a mature adult refers to the: a. cancellous bone between the alveoli b. layer of compact bone lining the alveolus c. part of the jaw that houses the teeth d. done surrounding the lamina dura

Answer 39

b. layer of compact bone lining the alveolus The alveolar bone proper of the jaws makes up the lining of the tooth socket or alveolus, which is also considered to be the lamina dura on radiographs. The part of the jaws that contains the roots of the teeth is the alveolar process or alveolar bone. The supporting alveolar bone consists of both cortical bone and trabecular bone. The cortical bone consists of a plate of compact bone on both the facial and lingual surfaces of the alveolar process. The trabecular bone consists of cancellous bone that is located between the alveolar bone proper and the plates of cortical bone.

Question 40

which of the following structures is not considered part of the periodontium? a. alveolar process b. cementum c. basal bone d. periodontal ligament

Answer 40

c. basal bone The part apical to the roots of the teeth is the basal bone, which then forms the body of the maxilla or body of the mandible and thus is not considered part of the periodontium. The alveolar process, cementum, and periodontal ligament are all parts of the periodontium.

Question 41

which of the following tisssue types is most likely to source of cementogenic cells in adults who have undergone root planning? a. bone marrow b. periodontal ligament c. residual cementum patches d. alveolar process

Answer 41

b. periodontal ligament The periodontal ligament has a line of cementoblasts along the cemental surface of the root that can produce cementum throughout the lifetime of the tooth.

Question 42

which of the following fiber groups of the periodontal ligament foes not contribute significantly to each tooth's anchorage in the jaw? a. gingival fiber group b. interdental fiber group c. alveodental fiber group d. interradicular fiber group

Answer 42

a. gingival fiber group The gingival fiber group does not support the tooth in relationship to the jaws, resisting any forces of mastication or speech; rather, this group supports only the marginal gingiva to maintain the relationship to the tooth. Instead, the interdental and alveodental, which the interradicular fiber group is part of, supports the tooth in relationship to the jaws.

Question 43

which of the following is not a part of the gingival fiber group? a. interdental fiber group b. circular fiber group c. dentoperiosteal fiber group d. alveologingival fiber group

Answer 43

a. interdental fiber group Another principal fiber other than the alveolodental ligament is the interdental ligament. The gingival fiber group includes the fiber subgroups of the circular and dentogingival ligament, as well as both the alveologingival and dentoperiosteal ligaments.

Question 44

the anchorage of the tooth to the alveolar process is mediated through which of the following? a. interdental ligament b. sharpey fibers c. oxytalan fibers d. both sharpey and oxytalan fibers

Answer 44

b. sharpey fibers Sharpey fibers in alveolar bone proper are each inserted at 90 degrees or perpendicular to the bone to mediate the anchorage of the tooth. A principal fiber of the periodontal ligament is the interdental ligament. Oxytalan fibers are a fiber type related to elastic fibers; they appear to consist of the microfibrillar component only, thereby resembling very immature elastic fibers.

Question 45

cellular cementum is most likely found around which of the following root regions? a. cervical part of the root b. entire root of an unerupted tooth c. apical part of the root d. furcation region of the root

Answer 45

c. apical part of the root Cellular cementum consists of the last layers of cementum deposited over the acellular cementum, mainly in the apical one third of each root. At least one layer of acellular cementum covers the entire outer surface of each root with many more layers covering the cervical one third near the cementoenamel junction.

Question 46

the lamina dura noted on radiographs corresponds to which of the following structures? a. basal bone of the both jaws b. buccal and lingual cortical plates of the jaws c. supporting cancellous bone between the teeth d. alveolar bone proper of the alveolar process

Answer 46

d. alveolar bone proper of the alveolar process The part of the alveolar bone proper of the alveolar process that is present on radiographs is considered the lamina dura, which is uniformly radiopaque (or lighter).

Question 47

which of the following includes both the supporting soft and hard dental tissue between and including parts of the tooth and surrounding bone? a. periodontal ligament b. periodontium c. alveolar bone proper d. alveolar process

Answer 47

b. periodontium The periodontium consists of both the supporting soft and hard dental tissue between the tooth and the alveolar process, as well as parts of the tooth and alveolar process. Thus, the periodontium includes the periodontal ligament as well as the alveolar process, which includes the alveolar bone proper.

Question 48

when many of the cementoblasts become entrapped by the cementum they produce, they become: a. odontoclasts b. odontoblasts c. cementocytes d. dental sac cells

Answer 48

c. cementocytes During the later steps within the stage of apposition of cementum, many of the cementoblasts become entrapped by the cementum they produce, becoming cementocytes. After the appositional growth of cementum in layers, the cementoblasts that do not become entrapped in cementum line up along the cemental surface along the length of the outer covering of the periodontal ligament. When the undifferentiated cells of the dental sac come into contact with the newly formed surface of root dentin, these cells are induced to become cementoblasts. Odontoblasts are cells that produce dentin. Odontoclasts resorb dentin, cementum, and enamel during tooth shedding and eruption.

Question 49

the alveolar process between two neighboring teeth is specifically called the _____ bone a. interdental b. basal c. interradicular d. trabecular

Answer 49

a. interdental The alveolar process that separates two neighboring teeth is the interdental septum or interdental bone. The part apical to the roots of the teeth is the basal bone, which then forms the body of the maxilla or body of the mandible. The alveolar process that separates the roots of the same tooth is the interradicular septum or interradicular bone. The trabecular bone consists of cancellous bone that is located between the alveolar bone proper and the plates of cortical bone.

Question 50

the most common cell in the periodontal ligament is the: a. cementoblast b. fibroblast c. odontoclast d. osteoclast

Answer 50

b. fibroblast Like all connective tissue, the fibroblast is the most common cell in the periodontal ligament, producing fibers and intercellular substance. The cementoblast and odontoclast as well as the osteoclast are present in the periodontal ligament. The cementoblast produces cementum and the odontoclast resorbs parts of the tooth during tooth shedding and eruption. The osteoclast resorbs the alveolar process.

Question 51

with occlusal trauma, there can be a widening of the: a. periodontal space b. periodontal ligament c. lamina dura d. periodontal space, periodontal ligament, and lamina dura

Answer 51

d. periodontal space, periodontal ligament, and lamina dura Early occlusal trauma can be viewed on radiographs as a widening of the radiolucent (or darker) periodontal ligament space between the radiopaque (or lighter) lamina dura of the alveolar bone proper and the similar radiopaque (or lighter) cementum. Because the periodontal space represents the periodontal ligament, the ligament can double and the individual principal fiber bundles also become thicker. Thickening of the lamina dura, which represents the alveolar bone proper, is also possible with occlusal trauma in response to overall alveolar process loss.

Question 52

which part of the periodontal ligament is noted to be wider in a healthy adult tooth? a. near the apex b. near the cervix c. both near the apex and cervix d. between the apex and cervix

Answer 52

c. both near the apex and cervix The periodontal ligament is wider near the apex and cervix of the tooth and narrower between these two end points.

Question 53

in which part of the alveolar process is the loss of bone from periodontitis first evident? a. interradicular bone b. basal bone c. supporting alveolar bone d. alveolar crest

Answer 53

d alveolar crest The bone loss from periodontitis is first evident in the most coronal part of the alveolar bone proper, the alveolar crest, which looks moth eaten both microscopically and radiographically. The alveolar process loss of the jaws, which involves the presence of the roots of the teeth, progresses apically to involve the interradicular bone if the tooth is multirooted, as well as the surrounding supporting alveolar bone, but does not involve the inferior bone of the jaws, the basal bone.

Question 54

which of the following is not bisible at least somewhat on bitewing radiographs? a. periodontal space b. lamina dura c. cortical bone d. trabecular bone

Answer 54

c. cortical bone The cortical bone is not visible on periapical or bitewing radiographs but only on occlusal radiographs as a uniformly radiopaque (or lighter) bony sheet, facial and lingual to the teeth. The periodontal space and lamina dura are both present somewhat. Only the parts of trabecular bone between the teeth and between the roots are ever present on any type of radiograph.

Question 55

which type of bone is only present in an area of anodontia? a. cortical bone b. basal bone c. alveolar bone proper d. trabecular bone

Answer 55

b. basal bone The developmental dental anomaly of anodontia, in which tooth germs are congenitally absent, may affect the development of the alveolar process of either jaw. Proper development is impossible because the alveolar unit of each dental arch only forms in response to the tooth germs in the area. Only basal bone will be present in each one of the involved areas of the jaws. The alveolar process, which includes the alveolar bone proper and the supporting alveolar bone, the latter of which consists of the cortical bone and trabecular bone, will not have developed due to the anodontia.

Question 56

Frontonasal process

Answer 56

Forms as a bulge of tissue at the most cephalic end, cranial boundary of stomodeum

Question 57

Lens placodes

Answer 57

Future eyes; initially located fishlike on each side of frontonasal process

Question 59

Otic placodes

Answer 59

Future **internal ear**; lateral & posterior to lens placodes

Question 60

Nasal placodes

Answer 60

Anterior part of frontonasal process; develop into olfactory epithelium for smell

Question 61

9. The neural crest cells migrate from which embryonic structures during prenatal development? a. Stomodeum b. First branchial arch c. Neural folds d. Frontonasal process

Answer 61

c.Neural folds

Question 62

18. Which of the following can occur that *mainly* involves the abnormal development of one or more structures from ectoderm within the embryonic period? a. Treacher Collins syndrome b. Ectodermal dysplasia c. Congenital syphilis d. Fetal alcohol syndrome

Answer 62

b.Ectodermal dysplasia

Question 63

4. From which embryonic layer is mesoderm derived during prenatal development? a. Epiblast layer b. Hypoblast layer c. Endoderm d. Neuroectoderm

Answer 63

a.Epiblast layer

Question 64

3. The mandibular arch during the embryonic period of prenatal development is the: a. fusion of the two paired mandibular processes. b. swelling found superior to the stomodeum. c. structure that gives rise to the lateral nasal process. d. posterior part of the hard palate.

Answer 64

a.fusion of the two paired mandibular processes.

Question 65

Which of the following is the BEST term used for the embryonic layer located between the ectoderm and the endoderm? a. Mesenchyme b. Ectomesenchyme c. Mesoderm d. Mesiodens

Answer 65

c. Mesoderm

Question 66

\_\_\_\_\_ is a layer in trilaminar embryonic disc derived from epiblast layer and lining stomodeum

Answer 66

Ectoderm

Question 67

16. What *best* characterizes the first week of prenatal development so that the blastocyst splits into smaller and more numerous cells? a. Implantation b. Mitotic cleavage c. Meiosis d. Fertilization

Answer 67

b.Mitotic cleavage

Question 68

17. What does the maxillary process form from during the fourth week of prenatal development? a. Lateral nasal processes b. Mandibular arch c. Intermaxillary segment d. Medial nasal processes

Answer 68

b.Mandibular arch

Question 69

20. The development of the neck parallels the development of the face over time, beginning during the fourth week of prenatal development within the embryonic period and completed during the _____ period. a. preimplantation b. embryonic c. fetal d. both the embryonic and fetal

Answer 69

c.fetal

Question 70

18. The fusion of the maxillary and medial nasal processes to form the upper lip is completed during the end of the _____ week of prenatal development, when the grooves between the processes are obliterated. a. fourth b. fifth c. sixth d. seventh

Answer 70

d.seventh

Question 71

5. In which week of prenatal development does facial development begin in the embryo? a. Second b. Fourth c. Fifth d. Eighth

Answer 71

b.Fourth

Question 72

13. The facial development that starts in the fourth week will be completed later in the _____ week within the fetal period. a. fifth b. sixth c. eighth d. twelfth

Answer 72

d.twelfth

Question 73

4. A type of cleft lip can result during prenatal development from the lack of fusion between _____ processes. a. mandibular and maxillary b. medial nasal and maxillary c. lateral nasal and medial nasal d. two lateral nasal e. lateral nasal and maxillary

Answer 73

b.medial nasal and maxillary

Question 74

Failure of fusion of the palatal shelves with the primary palate or each other will result in? A. Branchial cleft cyst B. Cleft palate C. Medial nasal process D.Zygote

Answer 74

**Cleft palate**

Question 75

What area of the **mandible** articulates with the **temporal bone** at the **TMJ?**

Answer 75

The head of the **condyle** of the mandible

Question 76

What **bones** are **articulated** with the **TMJ**?

Answer 76

The **temporal bone** and **condyle** of the **mandible**

Question 78

Name the **3 major salivary glands**

Answer 78

1. Stensen's duct (Parotid) 2. Bartholin's duct (Sublingual) 3. Wharton's duct (Submandibular)

Question 79

**region of the face** that includes the **forehead** and area **above eyes**

Answer 79

**frontal**

Question 80

**region of the face** that includes the **eyeball, supporting structures,** and **bony eye socket**

Answer 80

**orbital**

Question 81

**region of the face** which the main feature is the **external nose**

Answer 81

**nasal**

Question 82

What structure is located **between the eyes**? What is another name for the **tip of the nose**?

Answer 82

**root of nose** **apex of nose**

Question 83

**region of the face** located **inferior** to the **orbital region** and **lateral** to the **nasal region**

Answer 83

**infraorbital**

Question 84

**Region** of the face **lateral** of the **infraorbital region**?

Answer 84

**zygomatic region**

Question 85

**inferior** to the **zygomatic arch** and just **anterior** to the **external ear**

Answer 85

**temporomandibular joint**

Question 86

the **region of the face** composed of **soft tissue** of **cheeks** which is a broad area **between nose, mouth, ear**

Answer 86

**buccal region**

Question 87

On the **lateral aspect** of the **mandible**, the **stout, flat plate** of the \_\_\_\_\_\_\_\_\_\_ that extends **upward** and **backward** from the **body of the mandible** on each side

Answer 87

ramus, rami

Question 88

**anterior border** of the **ramus** is a **thin, sharp margin** that **terminates** in the\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_

Answer 88

**coronoid process**

Question 89

\_\_\_\_\_\_\_\_\_ ________ is the main part of the **anterior border of ramus** that forms a **concave forward curve**

Answer 89

**Coronoid notch**

Question 90

\_\_\_\_\_\_\_\_\_\_\_ ___________ is a **projection** at the **posterior border** of the **ramus** that is **thickened** and **extends** from the **angle of the mandible**

Answer 90

**Mandibular condyle**

Question 91

**strong muscle** that forms the **cheek** along with upper flesh and fat

Answer 91

**masseter muscle**

Question 92

In the **superficial** and **deep** part of the **masseter**, where is the **origin** and **insertion** points?

Answer 92

**Superficial part** ORIGIN: **maxillary process** of **zygomatic bone** and **anterior 2/3** of the **zygomatic process** of the maxilla INSERTION: **angle of the mandible** and **posterior part** of **ramus** **Deep part** ORIGIN: **medial aspect** of the **zygomatic arch** INSERTION: **central** and **upper** part of **ramus** as high as the **coronoid process**

Question 93

Where is the **origin,** **insertion,** and **action** of the **temporalis**?

Answer 93

**ORIGIN**: the **floor** of **temporal fossa** and **temporal fascia** **INSERTION**: the apex and deep surface of the **coronoid process** and along the **anterior border of the ramus** **ACTION: Anterior fibers elevate** the mandible, while the **posterior fibers retract** the mandible

Question 94

Where is the **origin** and **action** of the **lateral pterygoid muscle**?

Answer 94

ORIGIN: **Superior** portion - **infratemporal surface** of **greater wing of sphenoid.** **Inferior** portion - **lateral surface** of **lateral pterygoid plate** Action: **Depress, protrude** and **move** the **mandible** from **side to side**

Question 95

What is the **origin** and **action** of the **medial pterygoid muscle**?

Answer 95

ORIGIN: **medial surface** of the **lateral pterygoid plate**, the **posterior surface** of the tubercle of **palatine bone** and **tuberosity of maxilla** Action: **elevates** and **protracts** the **mandible** also moves the jaw from **side to side**

Question 97

4. The line of demarcation between the attached gingiva and the alveolar mucosa is the: a. mucogingival junction. b. interdental gingiva. c. mucobuccal fold. d. marginal gingiva.

Answer 97

a.mucogingival junction.

Question 98

The line of demarcation between the firmer and pinker attached gingiva and the movable and redder alveolar mucosa is the scallopp-shaped \_\_\_\_\_\_\_\_

Answer 98

Mucogingival junction

Question 99

There are 4 muscles of mastication: 1. Masseter 2. Temporalis 3. Medial pterygoid 4. Lateral pterygoid

Answer 99

All attach to the mandible and are innervated by **V₃** Form in the **tenth week** of development **First arches (mandibular arches)**

Question 100

Which of the following muscles is involved in the lateral deviation of the mandible? a. masseter muscle b. medial pterygoid muscle c. lateral pterygoid muscle d. temporalis muscle e. digastric muscle

Answer 100

c. lateral pterygoid muscle

Question 101

The ______ of the hyoid arches helps form the muscles of facial expression, the middle ear muscles, and a suprahyoid muscle.

Answer 101

mesoderm

Question 102

Which specific muscle can become clinically enlarged in patients who habitually clench or grind (with bruxism) their teeth and in those who constantly chew gum? a. Masseter muscle b. Lateral pterygoid muscle c. Medial pterygoid muscle d. Temporalis muscle

Answer 102

a. Masseter muscle

Question 103

Gingival margin ## Footnote .

Answer 103

the edge of the gingiva nearest to the incised surface of the tooth

Question 105

**Lateral pterygoid** The **superior head** originates from the **greater wing of the sphenoid**. The **inferior head** originates from the **lateral pterygoid plate** of the sphenoid. The two heads converge into a tendon, which attaches to the **neck of the mandible.**

Answer 105

short thick almost conical muscle of mastication superior to the medial pterygoid. **Two separate heads (superior an inferior).** They are separated anteriorly by a slight interval but fuse together posteriorly. The entire muscle lies within the **infratemporal fossa deep to the temporalis muscle.** The **only** muscle of mastication that **ASSISTS in depressing the mandible**, **lowering the lower jaw**! Depression of the mandible occurs during the opening of the jaws. Protrusion also occurs when the jaws are opened The muscle is innervated by the **lateral pterygoid nerve**, a branch of the **mandibular nerve** (V₃) **Pterygomandibular space** is formed by the **lateral pterygoid muscle (roof), medial pterygoid muscle (medial wall), and the mandibular ramus (lateral wall).** It is the injection site for the inferior alveolar block.

Question 106

22. On what structure do BOTH heads of the masseter muscle originate? a. Zygomatic process of the maxilla b. Coronoid process c. Zygomatic process of the frontal bone d. Zygomatic arch

Answer 106

d.Zygomatic arch

Question 108

Gingival sulcus

Answer 108

The crevice between the free gingiva and the tooth.

Question 109

Embryonic layers (germ layers)

Answer 109

increased number of **embryonic cells** within the **blastocyst**.

Question 110

1. The folding of the embryo during prenatal development causes _____ to be on the \_\_\_\_\_. a. endoderm; inside of the embryo b. ectoderm; inside of endoderm c. endoderm; outside of the mesoderm d. mesoderm; outside of the ectoderm

Answer 110

a.endoderm; inside of the embryo

Question 111

Alveolar mucosa

Answer 111

The thin, moveable, loosely attached tissue **covering the alveolar bone**. non keratinized

Question 113

**Medial pterygoid**

Answer 113

Rectangular form has 2 heads due to differing depth (deep and superficial, smaller head). The **superficial head** originates from the **maxillary tuberosity** and the pyramidal process of **palatine bone**. The **deep head** originates from the **lateral pterygoid plate of the sphenoid bone**. Both parts attach to the **ramus** of the mandible, near the angle of mandible. **DEEPEST MUSCLE OF MASTICATION** **Elevates the mandible** during the closing of the jaws Innervated by V₃

Question 114

4. A type of cleft lip can result during prenatal development from the lack of fusion between _____ processes. a. mandibular and maxillary b. medial nasal and maxillary c. lateral nasal and medial nasal d. two lateral nasal e. lateral nasal and maxillary

Answer 114

b.medial nasal and maxillary

Question 115

**Masseter**

Answer 115

**Most superficial and strongest**. Thick flat rectangular muscle on each side of the face, **anterior to the parotid gland**. **2 heads** (superficial and deep) Origin- Both heads **originate from the zygomatic arch.** Superficial =**angle of the mandible**. Deep = **ramus** When the patient **clenches their teeth** is when the **elevation of the mandible** is taking place (**closing of the jaws**) **Innervated by the Masseteric nerve (V₃)**

Question 116

How does cleft lip form?

Answer 116

**Failure of fusion** of the maxillary process with the medial nasal process

Question 118

**Temporalis**

Answer 118

broad **fan-shaped muscle** of mastication on each **side of the head** that fills the temporal fossa, **superior to the zygomatic arch**. Temporal space is formed by the **temporal fascia** covering the temporalis muscle. **Infratemporal space is bordered laterally by the medial surface of the mandible and the temporalis muscle.** originates from the **temporal fossa** – a shallow depression on the lateral aspect of the skull. Inserts on **coronoid process** Action- **retraction of mandible, elevating the mandible**. Also allows **freeway space** at its physiologic rest position Innervated by V₃

Question 119

15. On which of the following orofacial tissue is the linea alba located? a. Attached gingiva b. Marginal gingiva c. Labial mucosa d. Buccal mucosa

Answer 119

d.Buccal mucosa

Question 120

Free gingiva

Answer 120

closely adapted around each tooth but **not attached** keratinized

Question 121

Interdental papillae

Answer 121

Extensions of unattached gingiva between adjacent teeth keratinized fills embrasure spaces

Question 123

What’s the diff b/w meiosis and mitosis

Answer 123

Meiosis – The process of reproductive cell production that ensures the **correct number of chromosomes;** meiosis that takes place during **fertilization**. Mitosis – **cell division** that occurs in phases and results in **two daughter cells;** Mitosis is a process that **takes place during tissue growth or regeneration**

Question 124

Mucogingival junction

Answer 124

The line that marks the **connection between** the **attached gingiva** and the **alveolar mucosa** on the facial surfaces of all quadrants and the lingual surfaces of the mandibular arch

Question 126

Attached gingiva

Answer 126

Part of the gingiva that is **tightly connected** to the cementum on the root (cervical third) and to the connective tissue cover of the alveolar bone

Question 127

15. Which of the following muscles can show enlargement due to repetitive muscle contraction associated with clenching of the teeth in a patient? a. Buccinator muscle b. Masseter muscle c. Temporalis muscle d. Zygomatic muscle

Answer 127

b.Masseter muscle

Question 128

23. Which of the following muscles when contracted allows for the retraction of the mandible? a. Masseter muscle b. Temporalis muscle c. Lateral pterygoid muscle d. Medial pterygoid muscle

Answer 128

b.Temporalis muscle

Question 130

2. The philtrum of the upper lip forms during sixth week of prenatal development from the: a. mandibular processes. b. medial nasal processes. c. lateral nasal processes. d. nasal placodes.

Answer 130

b.medial nasal processes.

Question 133

The mucogingival junction is a line of demarcation between the attached gingiva and the: a. buccal mucosa. b. marginal gingiva. c. gingival sulcus. d. alveolar mucosa.

Answer 133

d. alveolar mucosa.

Question 134

18. Which of the following muscles when unilaterally contracted deviates the mandible to one side? a. Masseter muscle b. Lateral pterygoid muscle c. Medial pterygoid muscle d. Temporalis muscle

Answer 134

b.Lateral pterygoid muscle

Question 136

2. From the following list of muscles, select which are considered muscles of mastication. (*Select all that apply*.) a. Buccinator b. Risorius c. Platysma d. Temporalis e. Masseter

Answer 136

d. Temporalis e. Masseter

Question 138

21. Surrounding the teeth in the alveoli and covering the alveolar processes is the \_\_\_\_\_, which is composed of a firm pink tissue. a. gingiva b. minor salivary glands c. Fordyce spots d. linea alba

Answer 138

a.gingiva

Question 139

Which of the following muscles has two bellies, giving the muscles two different origins? a. lateral pteryoid b. geniohyoid c. thyrohyoid d. stylohyoid

Answer 139

a. lateral pteryoid

Question 140

17. The pink labial mucosa or buccal mucosa meets the redder _____ at the mucobuccal fold. a. marginal gingiva b. attached gingiva c. alveolar mucosa d. interdental papilla

Answer 140

c.alveolar mucosa

Question 141

What do the muscles of mastication work with to accomplish movements of the mandible? a. Maxillae b. Temporal bone c. Temporomandibular joint d. Zygoma e. Hard palate

Answer 141

c. Temporomandibular joint

Question 142

8. Which of the following muscles inserts onto the coronoid process? a. Lateral pterygoid muscle b. Masseter muscle c. Medial pterygoid muscle d. Temporalis muscle

Answer 142

d.Temporalis muscle

Question 143

Which muscle listed below is MOST superficial in regard to location? a. masseter muscle b. medial pterygoid muscle c. lateral pterygoid muscle d. superior pharyngeal constrictor muscle

Answer 143

c. lateral pterygoid muscle

Question 144

Which of the following descriptions concerning the masseter muscle is CORRECT? a. most superficial muscle of the facial expression b. originates from the zygomatic arch c. insert on the medial surface of the mandible's angle d. depresses the mandible during jaw movement

Answer 144

b. originates from the zygomatic arch

Question 145

Which of the following muscles is considered a muscle of mastication? a. buccinator b. risorius c. mentalis d. masseter e. corrugator supercilii

Answer 145

d. masseter

Question 146

How many **X-type chromosomes** are necessary for the **embryo** to become of the **female gender** when present during **prenatal development**? a. One b. Two c. Three d. Four

Answer 146

**Two** ***A person is born with 23 pairs of chromosomes - a total of 46.** The photographic analysis of a person’s **chromosomes** is done by orderly arrangement of the pairs in a karyotype, with the **sex** known by the presence of either **XX chromosomes for females** or **XY for males.***

Question 148

20. The development of the neck parallels the development of the face over time, beginning during the fourth week of prenatal development within the embryonic period and completed during the _____ period. a. preimplantation b. embryonic c. fetal d. both the embryonic and fetal

Answer 148

c.fetal

Question 149

17. What does the maxillary process form from during the fourth week of prenatal development? a. Lateral nasal processes b. Mandibular arch c. Intermaxillary segment d. Medial nasal processes

Answer 149

b.Mandibular arch

Question 150

1. The folding of the embryo during prenatal development causes _____ to be on the \_\_\_\_\_. a. endoderm; inside of the embryo b. ectoderm; inside of endoderm c. endoderm; outside of the mesoderm d. mesoderm; outside of the ectoderm

Answer 150

a.endoderm; inside of the embryo

Question 151

4. A type of cleft lip can result during prenatal development from the lack of fusion between _____ processes. a. mandibular and maxillary b. medial nasal and maxillary c. lateral nasal and medial nasal d. two lateral nasal e. lateral nasal and maxillary

Answer 151

b.medial nasal and maxillary

Question 152

9. The neural crest cells migrate from which embryonic structures during prenatal development? a. Stomodeum b. First branchial arch c. Neural folds d. Frontonasal process

Answer 152

c.Neural folds

Question 153

24. The developmental disturbance of cleft lip is *more* commonly found: a. in males. b. bilaterally. c. on the right side. d. on the lower lip.

Answer 153

a.in males.

Question 154

What’s the diff b/w meiosis and mitosis

Answer 154

Meiosis – The process of reproductive cell production that ensures the **correct number of chromosomes;** meiosis that takes place during **fertilization**. Mitosis – **cell division** that occurs in phases and results in **two daughter cells;** Mitosis is a process that **takes place during tissue growth or regeneration**

Question 155

3. The mandibular arch during the embryonic period of prenatal development is the: a. fusion of the two paired mandibular processes. b. swelling found superior to the stomodeum. c. structure that gives rise to the lateral nasal process. d. posterior part of the hard palate.

Answer 155

a.fusion of the two paired mandibular processes.

Question 156

12. The _____ are rounded areas of specialized, thickened ectoderm found at the location of developing special sense organs. a. placodes b. branchial arches c. branchial pouches d. processes

Answer 156

a.placodes

Question 157

2. The philtrum of the upper lip forms during sixth week of prenatal development from the: a. mandibular processes. b. medial nasal processes. c. lateral nasal processes. d. nasal placodes.

Answer 157

b.medial nasal processes.

Question 158

Process of reproductive cell production that ensures correct number of chromosomes

Answer 158

Meiosis

Question 159

19. The maxillary processes on each side of the developing face partially fuse with the mandibular arch on each side to create the: a. philtrum. b. tubercle. c. labial commissures. d. lower lip.

Answer 159

c.labial commissures.

Question 160

in week 4 (embryonic period), name the events that occur within the organism as it develops (in order): (Hint/trick to remember-**fold, feed, face**)

Answer 160

1. ) trilaminar embryonic disk undergoes anterior (cephalic) and lateral embryonic folding (endoderm inside ecto+meso) 2. ) formation of tube that becomes future digestive tract from cephalic (oropharyngeal membrane) to caudal (cloacal membrane) end. (Foregut [anterior], Midgut [posterior], Hindgut[posterior]) 3. ) Development of face and neck (primitive eyes, ears, nose, oral cavity, and jaw areas)

Question 162

4. From which embryonic layer is mesoderm derived during prenatal development? a. Epiblast layer b. Hypoblast layer c. Endoderm d. Neuroectoderm

Answer 162

a.Epiblast layer

Question 163

18. Which of the following can occur that *mainly* involves the abnormal development of one or more structures from ectoderm within the embryonic period? a. Treacher Collins syndrome b. Ectodermal dysplasia c. Congenital syphilis d. Fetal alcohol syndrome

Answer 163

b.Ectodermal dysplasia

Question 164

6. Which of the following facial structures is formed from the mandibular arch during prenatal development? a. Forehead b. Lower face c. Philtrum d. Nose

Answer 164

b.Lower face

Question 165

24. What is the *exact* term for the process that affords the development of specific tissue structure or differing form due to embryonic cell migration and inductive interactions? a. Folding b. Morphogenesis c. Proliferation d. Appositional or interstitial growth

Answer 165

b.Morphogenesis

Question 166

13. The facial development that starts in the fourth week will be completed later in the _____ week within the fetal period. a. fifth b. sixth c. eighth d. twelfth

Answer 166

d.twelfth

Question 167

**What condition** develops from the **neural tube failing to fuse properly**, characterized by **defects** in the **vertebral arches** and **various degrees of disability**?

Answer 167

**Spina Bifida**

Question 168

During which **week** of **prenatal development** does the **neural plate differentiate**? a. Second week b. Third week c. Fourth week d. Fifth week

Answer 168

b. **Third week** * A **specialized group of cells differentiates** from the **ectoderm** and is now **considered neuroectoderm**. These **cells are localized to the neural plate** of the **embryo**, a central band of cells that extends the length of the embryo, from the **cephalic end** to the **caudal end**, during the **third week of prenatal development. This plate undergoes further growth** and thickening, which causes it to deepen and invaginate inward, forming the **neural groove.***

Question 169

By the end of the **first week** of **prenatal development**, the **blastula stops traveling** and undergoes: a. implantation. b. migration. c. disintegration. d. amniocentesis.

Answer 169

a. **Implantation** By the end of the **first week**, the **blastocyst stops traveling** and undergoes **implantation**; thus it becomes embedded in the prepared endometrium, the innermost lining of the uterus on its back wall.

Question 170

Found in **early prenatal development**, the **neural tube** will **form in the future** which of the following **structures**? a. Heart b. Spinal cord c. Face d. Digestive tract

Answer 170

**Spinal cord** *As further growth of the neuroectoderm occurs, the **neural tube** is formed during the **fourth week** by the **neural folds undergoing fusion** at the most superior part. The **neural tube forms the future spinal cord** as well as other **neural tissue** of the **central nervous system.***

Question 171

Within **fully mineralized bone** are **osteocytes**, which are **entrapped mature** **_osteoclasts_**. **Osteoblasts** never undergo **mitosis** during tissue formation, and thus **only one** **osteocyte** is ever found in a **lacuna.**

Answer 171

The **first** statement is **false** the **second** statement is **true.**

Question 172

What are the **3 Embryonic Layers** involved in **facial development**? During **what week** does the **face begin to form** and during **what week** does the **face development end**?

Answer 172

**Ectoderm, Mesoderm,** and **Endoderm** **Begins in the 4th** Week and **ends** in the **12th Week**

Question 174

What are the **dentin** levels **(% inorganic, organic, water**)

Answer 174

**70% inorganic (mineralized)** **20% organic** 10% water

Question 175

During which week of prenatal development is the **palate completed**? a. Fifth b. Eighth c. Tenth d. Twelfth

Answer 175

d. ## Footnote **Twelfth**

Question 176

The **tongue develops** from multiple swellings derived from the: a. outer parts of the maxillary process. b. inferior growth of the intermaxillary segment. c. palatal shelves of the maxillary process. d. first four branchial arches.

Answer 176

d. ## Footnote **first four branchial arches.**

Question 177

The fusion of the **two palatal shelves** with the primary palate is dependent on the: a. ingrowth from the maxillary arch. b. change in position of the paranasal sinuses. c. continued vertical growth of all the processes. d. change in the position of the tongue.

Answer 177

d. change in the position of the **tongue**.

Question 178

During **tongue development**, what does the **epiglottic swelling** develop from? a. Outer parts of the maxillary process b. Inferior growth of the intermaxillary segment c. Palatal shelves of the maxillary process d. First four branchial arches

Answer 178

d. First four branchial arches * posterior swelling that develops from the mesenchyme of the fourth branchial arches marking the development of future epiglottis*

Question 179

Which of the following statements concerning tongue disturbances is *correct*? a. Abnormalities of the tongue are common. b. Ankyloglossia results from a long attachment of the lingual frenum. c. Ankyloglossia may be associated with other craniofacial abnormalities. d. Lingual frenum is never surgically cut anymore to free it.

Answer 179

c. **Ankyloglossia** may be associated with other **craniofacial abnormalities**.

Question 180

During the **sixth week** of prenatal development, within the embryonic period, the **bilateral maxillary processes** give rise to **paired**: a. lateral nasal processes. b. medial nasal processes. c. palatal shelves. d. mandibular processes.

Answer 180

c. **palatal shelves**.

Question 181

Which teeth are associated with the further development of the **primary palate**? a. Maxillary incisors b. Mandibular incisors c. Maxillary canines d. Mandibular posterior teeth

Answer 181

a. ## Footnote **Maxillary incisors**

Question 182

What happens to the specific cells from the **enamel organ** that will differentiate into **preameloblasts**? a. Their length shortens. b. Their nuclei repolarize. c. Their cellular contents mineralize. d. They line up along the basement membrane.

Answer 182

b.Their **nuclei repolarize**.

Question 183

Which embryonic structure is specifically responsible for the **development of the root**? a. Stellate reticulum b. Enamel organ c. Stratum intermedium d. Cervical loop

Answer 183

d. **Cervical loop**

Question 184

During root development, the **Hertwig epithelial root sheath** is entirely composed of: a. all layers of the enamel organ. b. enamel organ and dental papilla. c. inner and outer cells of the dental papilla. d. inner and outer enamel epithelium.

Answer 184

d. ## Footnote **inner and outer** **enamel epithelium.**

Question 185

The **dental lamina** is an embryonic structure that **develops from** the: a. oral epithelium. b. mesenchyme. c. neural crest cells. d. endodermal layer.

Answer 185

a. **oral epithelium**.

Question 186

Enamel **hypo**calcification is a type of **enamel dysplasia** that involves: a. an increased number of ameloblasts. b. a reduction in the quantity of enamel matrix. c. grooves and pitting on the enamel surface. d. interference in the metabolic processes of ameloblasts.

Answer 186

d. **interference** in the **metabolic processes** of **ameloblasts**.

Question 187

Which of the following statements concerning **active eruption** of a **permanent succedaneous** tooth is *correct*? a. The tooth erupts when the root is completed. b. The shedding of the associated primary tooth is intermittent. c. The first junctional epithelium is from the surrounding dental sac. d. The tooth actively erupts as gingival recession occurs.

Answer 187

b. The **shedding** of the associated **primary tooth** is **intermittent**. (**irregular intervals**)

Question 188

How many **buds** in the **dental lamina** appear along each **dental arch** during **odontogenesis** of the primary dentition? a. 5 b. 10 c. 15 d. 20

Answer 188

b. ## Footnote **10**

Question 189

**Nonsuccedaneous permanent teeth** develop from **buds** that grow off an extension of: a. each successional dental lamina. b. both paired palatal shelves. c. the posterior part of the intermaxillary segment. d. each primary second molar’s dental lamina.

Answer 189

d. each primary **second molar’s dental lamina**.

Question 190

During the **cap stage** of tooth development, the **tooth germ** consists of: a. enamel organ and dental sac. b. enamel organ and dental papilla. c. enamel organ, dental sac, and dental papilla. d. dental sac and dental papilla.

Answer 190

c. **enamel organ**, **dental sac**, and **dental papilla**.

Question 191

The **outer cells** of the **dental papilla** are **induced** to differentiate during tooth development into: a. pulp tissue. b. preameloblasts. c. odontoblasts. d. cementoblasts.

Answer 191

c. **odontoblasts**.

Question 192

Which of the following embryonic structures becomes the **dentinoenamel junction** during the completion of tooth development? a. Inner cells of the dental papilla b. Outer cells of the dental papilla c. Outer enamel epithelium of the enamel organ d. Basement membrane between the enamel organ and dental papilla

Answer 192

d. **Basement membrane** between the **enamel organ** and **dental papilla**

Question 193

Which of the following structures is ***not*** part of the **enamel organ**? a. Stellate reticulum b. Stratum intermedium c. Odontoblastic layer d. Outer epithelial cells

Answer 193

c. **Odontoblastic layer3`**

Question 194

The **initiation stage** of **odontogenesis** *mainly* involves the process of: a. differentiation. b. proliferation. c. induction. d. morphogenesis.

Answer 194

c. **induction (6-7th week)** ## Footnote **I -- I** **B--P** **C--PDM** **B--PDM** **A--IP** **M--M**

Question 195

Where does the **dental lamina** begin to form *first* in the developing dental arches? a. Near the midline b. Adjacent to the mental foramen c. Over the region of the future molars d. Adjacent to the developing temporomandibular joint

Answer 195

a. **Near the midline** **(incisors)**

Question 196

Which **permanent teeth** undergo **partial** **anodontia** the *most* within the developing oral cavity? a. Third molars b. Mandibular second premolars c. Maxillary lateral incisors d. Maxillary first premolars

Answer 196

a. **Third molars** ***Anodontia**- the lack of initiation within the **dental lamina** results in the **absence** of a **single tooth** or **multiple teeth (partial)** or an entire dentition (complete),*

Question 197

What is the known **etiology (cause)**of **supernumerary teeth**? a. Hereditary factors b. Occlusal trauma involvement c. Interatogen considerations d. Disintegration of associated membranes

Answer 197

a. **Hereditary factors** ## Footnote **(6th-7th week Initiation stage)**

Question 198

Which of the following permanent teeth can be considered **nonsuccedaneous**? a. Incisors b. Canines c. Premolars d. Molars

Answer 198

d. **Molars** **Primary Molars → Premolars** **Permanent molars grow on their own**

Question 199

Which stage of tooth formation occurs for the primary dentition during the **eleventh and twelfth week** of prenatal development? a. Bell stage b. Initiation stage c. Cap stage d. Bud stage

Answer 199

a. **Bell stage** Initiation stage (6-7th week) Bud stage (8th) Cap stage (9-10th week) Bell stage (11-12th week)

Question 200

What is the **angled part** of the **ameloblast** that **secretes** the **enamel matrix**? a. Inner enamel epithelium b. Repolarized preameloblasts c. Tomes process d. Disintegrating basement membrane

Answer 200

c. **Tomes process** ***(Ameloblast) = Tomes process → secretes enamel matrix***

Question 201

Where does the **initial teeth** for **both dentitions** develop? a. Anterior maxillary region b. Anterior mandibular region c. Posterior maxillary region d. Posterior mandibular region

Answer 201

b. **Anterior mandibular region** ***mandibular incisors***

Question 202

During what period of prenatal development is ***most*** of the **permanent dentition formed**? a. Preimplantation period b. Embryonic period c. Fetal period d. Both embryonic and fetal period

Answer 202

c. **Fetal period**

Question 203

**Lack of initiation** within the **dental lamina** results in the **absence of a single tooth or multiple teeth**, producing: a. supernumerary teeth. b. anodontia. c. dens in dente. d. germination.

Answer 203

b. **anodontia.** ## Footnote **(6-7th week)**

Question 204

When does **tongue development** occur during prenatal development? a. During the fourth to fifth week b. During the fourth to eighth week c. During the eighth to tenth week d. During the eighth to twelfth week

Answer 204

b.During the **fourth** to **eighth week** the **body of the tongue** develops from the **first branchial arch**, and the **base of the tongue** originates later from the **second., third, and fourth** branchial arches.

Question 205

As the tongue develops still further, the **copula** of the **tongue base**, after overgrowing the **second branchial arch**, merges with the **anterior swellings** of the **first branchial arch** of the tongue body, with the fusion is **superficially demarcated** by the: a. sulcus terminalis. b. tuberculum impar. c. copula. d. median lingual sulcus.

Answer 205

a. **sulcus terminalis.**

Question 208

Which part of the **tooth germ** is the primary source for the **periodontal ligament (PDL)** of the tooth? a. Dental sac b. Hertwig epithelial root sheath c. Stratum intermedium d. Central cells of dental papilla

Answer 208

a. **Dental sac** **Mesoderm → Dental sac = PDL, cemuntum and some alvelor bone**

Question 209

What term describes the **movement of the nuclei within the inner enamel epithelium** as the tissue forms into **preameloblasts**? a. Dentinogenesis b. Repolarization c. Disintegration d. Maturation

Answer 209

b. **Repolarization** **movement of nuclei = repolarization​**

Question 210

Which of the following functions are performed by the **Golgi complex** within the cell? a. Metabolizes foreign compounds b. Produces ribosomes c. Packages protein compounds d. Produces energy for the cell

Answer 210

c. **Packages protein compounds** * Golgi complex: **Responsible for** the packaging, segregation, and **transporting proteins into secretory vesicles** without losing or mixing of the cytoplasm within the cell*

Question 211

The **specialized, metabolically active structures** within the cell are *generally* considered to be: a. nuclear pores. b. organelles. c. chromosomes. d. vacuoles.

Answer 211

b. **organelles**.

Question 212

Which of the following basic tissue types is usually composed of **fewer cells spaced farther apart** and **containing larger amounts of matrix between the cells**? a. Epithelium b. Nerve tissue c. Muscle tissue d. Connective tissue

Answer 212

d. **Connective tissue**

Question 213

The **macrophages** found in the **connective tissue** are derived from: a. neutrophils. b. monocytes. c. basophils. d. mast cells.

Answer 213

b. **monocytes.** Other cells found in **connective tissue** include migrated white blood cells from the blood supply, such as **monocytes (macrophages),** **basophils (mast cells)**

Question 214

During the cell cycle, **interphase** involves the cells engaging in: a. organelle replacement. b. substance destruction. c. chromatin removal. d. centrosome reduction.

Answer 214

a. **organelle replacement.** Interphase: Period when a cell is between divisions but is growing and functioning. Mitosis: Interphase→Prophase→Metaphase→Anaphase→Telophase **IPM AT**

Question 215

How many **phases** are within **mitosis** or cell division? a. One b. Two c. Three d. Four

Answer 215

d. **Four** **1. Prophase** **2. Metaphase** **3. Anaphase** **4. Telophase**

Question 216

Which of the following **organelles** in a cell can appear microscopically either **smooth or rough**? a. Golgi complex b. Lysosomes c. Cytoskeleton d. Endoplasmic reticulum

Answer 216

d. **Endoplasmic reticulum (ER)** **ER** = **Membrane-bound organelle with** **channels** that is either **rough or smooth**

Question 217

Which of the following tissue types **provides nutrition** for the underlying **compact bone**? a. Cartilage b. Periosteum c. Compact bone d. Cancellous bone

Answer 217

b. **Periosteum**

Question 218

Which of the following structures **separates the epithelium** from the **connective tissue**? a. Submucosa b. Basement membrane c. Periosteum d. Endosteum

Answer 218

b. **Basement membrane**

Question 219

Which of the following tissue types **covers and lines** *both* the **external and internal body surfaces**? a. Adipose b. Connective tissue c. Cartilage d. Epithelium

Answer 219

d. **Epithelium**

Question 220

Which type of **blood cell** is *directly* responsible for **immunoglobulin** **production**? a. Neutrophils b. Basophils c. Plasma cells d. Mast cells

Answer 220

c. **Plasma cells** **lymphocytes = plasma cells**

Question 221

What is the term used to **describe the amount of time** it takes for **newly divided cells** to be **completely replaced** throughout a tissue? a. Fusion b. Mitosis c. Turnover d. Meiosis

Answer 221

c. **Turnover**

Question 228

Which of the following is a **projection** of the **basal or secretory** end of each **ameloblast** that faces the **dentinoenamel junction**? a. Enamel spindle b. Tomes process c. Tomes granular layer d. Hunter-Schreger bands

Answer 228

b. Tomes process

Question 229

Which of the following **cell types** are ***not* renewable** during the lifetime of the tooth? a. Ameloblasts b. Odontoblasts c. Odontoclasts d. Cementoblasts

Answer 229

a. **Ameloblasts**

Question 230

**Enamel matrix** is a(n) _____ product because **ameloblasts** are derived from the **inner enamel epithelium** of the enamel organ. a. ectodermal b. endodermal c. mesodermal d. neural crest cell

Answer 230

a.**ectodermal = outer**

Question 231

The **attached gingiva** of the **oral cavity** consists of which type of **oral mucosa**? a. Alveolar mucosa b. Masticatory mucosa c. Specialized mucosa d. Lining mucosa

Answer 231

b. **Masticatory mucosa** *masticatory mucosa is a type of oral mucosa noted for its **rubbery surface texture and resiliency.** Masticatory mucosa includes that of the **hard palate, attached gingiva, and dorsal surface of the tongue**. Mucosa associated with**keratinized stratified squamous** epithelium.*

Question 232

What type of tissue makes up the **bulk** of the **lamina propria** of the **oral mucosa**? a. Connective tissue b. Muscle tissue c. Nerve tissue d. Epithelium

Answer 232

a.**Connective tissue**

Question 233

The **interdental gingiva** assumes a **nonvisible concave** form **between** the **facial and lingual gingival surfaces** called the: a. col. b. papilla. c. free gingival crest. d. gingival apex of the contour.

Answer 233

a.**Col.**

Question 234

**Cell renewal** of the **junctional epithelium** takes place in the: a. internal basal lamina. b. external basal lamina. c. lamina propria. d. basal layer of the tissue

Answer 234

d.**basal layer** of the tissue

Question 235

Which of the following has **no stippling** & is **free** from **underlying tooth.** A. attached gingiva B. free gingival groove C. Marginal Gingiva/Free Gingiva D. free gingival width

Answer 235

Marginal Gingiva/Free Gingiva

Question 236

What structure is responsible for **root development**? (A) Cervical Loop (B) Hertwig Epithelial Root Sheath (C) Cementocytes (D) Cementogenesis

Answer 236

**Cervical Loop**; most cervical part of enamel organ

Question 237

Both the **attached gingiva** and **buccal mucosa** are ***mainly* pinkish** in color and ***not* reddish** due to the: a. vascularity of the lamina propria. b. closeness to bone tissue. c. decreased number of melanocytes. d. increased thickness of the epithelial layers.

Answer 237

d.**increased thickness** of the **epithelial layers**

Question 238

Which of the following occurs with the **deposition of minerals** into **mature enamel**? a. Demineralization b. Erosion c. Remineralization d. Abfraction

Answer 238

c. **Remineralization**

Question 239

**Enamel matrix** is produced by the _____ cells. a. ameloblasts b. odontoblasts c. odontoclasts d. cementoblasts

Answer 239

a.**Ameloblasts**

Question 240

Which of the following has the ***highest*** rate of **turnover**? a. Oral epithelium b. Sulcular epithelium c. Junctional epithelium d. All have an equally high rate

Answer 240

c.**Junctional epithelium** ***JE turnover = 4-6 days​​***

Question 241

The **lining mucosa** is **keratinized**. True or False

Answer 241

**False** **Lining mucosa = mucosa** associated with **nonkeratinized stratified squamous epithelium.**

Question 242

The **outer cells** of the **dental papilla** are induced to **differentiate** during **tooth development** into: a. pulp tissue. b. preameloblasts. c. odontoblasts. d. cementoblasts.

Answer 242

c. **odontoblasts.**

Question 243

\_\_\_\_\_\_; the function of this membrane is to **shape the root.** (A) Cervical Loop (B) Hertwig Epithelial Root Sheath (C) Cementocytes (D) Cementogenesis

Answer 243

**Hertwig Epithelial Root Sheath (HERS)**

Question 244

**Dentin forming cells**? (A) Ameloblasts (B) Odontoblasts (C) Outer cells (dental papilla) (E) Preameloblast

Answer 244

**Odontoblasts**