Histology Final

Question 1

Sharpey’s fibers are located in which of the following types of dental tissue?

a. enamel
b. dentin
c. cementum
d. pulp

Answer 1

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 2

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 2

ramus

Question 3

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 3

b.medial nasal

and

maxillary

Question 4

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 4

a.

sulcus terminalis.

Question 5

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 5

d.increased thickness of the epithelial layers

Question 6

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 6

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 7

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 7

d.basal layer of the tissue

Question 8

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 8

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 9

Dentin forming cells?

A. Ameloblasts
B. Odontoblasts
C. Outer cells (dental papilla)
E.Preameloblast

Answer 9

Odontoblasts

Question 10

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

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

Answer 10

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 11

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

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

Answer 11

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 12

Predentin is the initial material laid down by the:

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

Answer 12

a. odontoblasts.

Predentin is a mesenchymal product consisting of nonmineralized collagen fibers produced by the odontoblasts. Ameloblasts —> preameloblasts —–> enamel. Odontoclasts are active during eruption, removing parts of the primary tooth.

Question 13

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 13

d.

inner and outer

enamel epithelium.

Question 14

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 14

c. enamel organ,

dental sac,

and

dental papilla.

Question 15

During the cell cycle, interphase involves the cells engaging in:

a. organelle replacement.
b. substance destruction.
c. chromatin removal.
d. centrosome reduction.

Answer 15

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 16

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 16

c. palatal shelves.

Question 17

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 17

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

Question 18

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 18

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 19

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 19

c. Fetal period

Question 20

During which week of prenatal development does the neural plate differentiate?

a. Second week
b. Third week
c. Fourth week
d. Fifth week

Answer 20

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 21

During which week of prenatal development is the palate completed?

a. Fifth
b. Eighth
c. Tenth
d. Twelfth

Answer 21

d.

Twelfth

Question 22

Enamel hypocalcification 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 22

d. interference in the metabolic processes of ameloblasts.

Question 23

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 23

a.ectodermal = outer

Question 24

Enamel matrix is produced by the _____ cells.

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

Answer 24

a.Ameloblasts

Question 25

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 25

Cleft palate

Question 26

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 26

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 27

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 27

d. Temporalis
e. Masseter

Question 28

From which embryonic layer is mesoderm derived during prenatal development?

a. Epiblast layer
b. Hypoblast layer
c. Endoderm
d. Neuroectoderm

Answer 28

a.Epiblast layer

Question 29

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 29

b.

10

Question 30

How many phases are within mitosis or cell division?

a. One
b. Two
c. Three
d. Four

Answer 30

d. Four

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

Question 31

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 31

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 32

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 32

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 33

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 33

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 34

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 34

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 35

In which week of prenatal development does facial development begin in the embryo?

a. Second
b. Fourth
c. Fifth
d. Eighth

Answer 35

b.Fourth

Question 36

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 36

b. anodontia.

(6-7th week)

Question 37

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 37

a. from pulp tissue 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 38

Name the 3 major salivary glands

Answer 38

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

Question 39

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 39

d. each primary second molar’s dental lamina.

Question 40

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 proper

Answer 40

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 41

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 41

d.Zygomatic arch

Question 42

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 42

d.Buccal mucosa

Question 43

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 43

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 **DEJ.** **Tertiary dentin** forms quickly in **localized regions** in response to a **localized tooth trauma** to the **exposed dentin.

Question 44

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 44

a.gingiva

Question 45

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 45

c. Temporomandibular joint

Question 46

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 46

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 47

the alveolar process between two neighboring teeth is specifically called the _____ bone

a. interdental
b. basal
c. interradicular
d. trabecular

Answer 47

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 48

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 48

b. Sharpey’s 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 49

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 49

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 withkeratinized stratified squamous epithelium.

Question 50

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 50

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 51

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 51

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 52

The dental lamina is an embryonic structure that develops from the:

a. oral epithelium.
b. mesenchyme.
c. neural crest cells.
d. endodermal layer.

Answer 52

a. oral epithelium.

Question 53

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 53

c.fetal

Question 54

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 54

a.in males.

Question 55

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 55

twelfth

Question 56

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 56

a.endoderm; inside of the embryo

Question 57

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 57

d.seventh

Question 58

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 58

d.

change in the position of the tongue.

Question 59

The initiation stage of odontogenesis mainly involves the process of:

a. differentiation.
b. proliferation.
c. induction.
d. morphogenesis.

Answer 59

c. induction (6-7th week)

I – I

B–P

C–PDM

B–PDM

A–IP

M–M

Question 60

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 60

a.Col.

Question 61

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 61

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 62

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 62

a.mucogingival junction.

Question 63

The lining mucosa is keratinized.

True or False

Answer 63

False

Lining mucosa = mucosa associated with nonkeratinized
stratified squamous epithelium.

Question 64

The macrophages found in the connective tissue are derived from:

a. neutrophils.
b. monocytes.
c. basophils.
d. mast cells.

Answer 64

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 65

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 65

a.fusion of the two paired mandibular processes.

Question 66

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 66

c.labial commissures.

Question 67

the most common cell in the periodontal ligament is the:

a. cementoblast
b. fibroblast
c. odontoclast
d. osteoclast

Answer 67

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 68

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 68

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.*

Question 69

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 69

a. collagen

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

Question 70

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 70

c.Neural folds

Question 71

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 71

c. odontoblasts.

Question 72

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 72

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 73

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 73

b.medial nasal processes.

Question 74

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 74

c.alveolar mucosa

Question 75

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 75

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 76

The specialized, metabolically active structures within the cell are generally considered to be:

a. nuclear pores.
b. organelles.
c. chromosomes.
d. vacuoles.

Answer 76

b. organelles.

Question 77

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 77

d.

first four branchial arches.

Question 78

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 78

a.placodes

Question 79

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 79

c. odontoblasts.

Question 80

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

Answer 80

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

Question 81

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 81

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.*

Question 82

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 82

b.Mitotic cleavage

Question 83

What bones are articulated with the TMJ?

Answer 83

The temporal bone and condyle of the mandible

Question 84

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 84

b.Mandibular arch

Question 85

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 85

b.Their nuclei repolarize.

Question 86

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 86

c. Tomes process

(Ameloblast) = Tomes process → secretes enamel matrix

Question 87

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 87

b.Morphogenesis

Question 88

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 88

a. Hereditary factors

(6th-7th week Initiation stage)

Question 89

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 89

c. Turnover

Question 90

What structure is responsible for root development?

(A) Cervical Loop
(B) Hertwig Epithelial Root Sheath
(C) Cementocytes
(D) Cementogenesis

Answer 90

Cervical Loop; most cervical part of enamel organ

Question 91

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 91

b. Repolarization

movement of nuclei = repolarization​

Question 92

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 92

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 93

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 93

a.Connective tissue

Question 94

What’s the diff b/w meiosis and mitosis

Answer 94

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 95

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 95

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 96

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 96

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 97

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 97

a. Near the midline

(incisors)

Question 98

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 98

b. Anterior mandibular region

mandibular incisors

Question 99

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 99

d. Cervical loop

Question 100

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 100

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 101

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 101

c. lateral pterygoid muscle

Question 102

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 102

d. Connective tissue

Question 103

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 103

b.Ectodermal dysplasia

Question 104

Which of the following cell types are not renewable during the lifetime of the tooth?

a. Ameloblasts
b. Odontoblasts
c. Odontoclasts
d. Cementoblasts

Answer 104

a. Ameloblasts

Question 105

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 105

b. originates from the zygomatic arch

Question 106

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 106

d.

Basement membrane between

the enamel organ and dental papilla

Question 107

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 107

b.Lower face

Question 108

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 108

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 109

which of the following fiber groups of the periodontal ligament does 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 109

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 110

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 110

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 111

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 111

Marginal Gingiva/Free Gingiva

Question 112

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 112

c.Junctional epithelium

JE turnover = 4-6 days​​

Question 113

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 113

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 114

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 114

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 115

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 115

b. Tomes process

Question 116

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 116

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 117

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 117

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 118

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 118

c. Mesoderm

Question 119

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 119

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 120

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 120

b.Masseter muscle

Question 121

Which of the following muscles has two bellies, giving the muscles two different origins?

a. lateral pteryoid
b. geniohyoid
c. thyrohyoid
d. stylohyoid

Answer 121

a. lateral pteryoid

Question 122

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 122

d.Temporalis muscle

Question 123

Which of the following muscles is considered a muscle of mastication?

a. buccinator
b. risorius
c. mentalis
d. masseter
e. corrugator supercilii

Answer 123

d. masseter

Question 124

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 124

c. lateral pterygoid muscle

Question 125

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 125

b.Temporalis muscle

Question 126

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 126

b.Lateral pterygoid muscle

Question 127

Which of the following occurs with the deposition of minerals into mature enamel?

a. Demineralization
b. Erosion
c. Remineralization
d. Abfraction

Answer 127

c. Remineralization

Question 128

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 128

d. Endoplasmic reticulum (ER)

ER = Membrane-bound organelle with

channels that is either rough or smooth

Question 129

Which of the following permanent teeth can be considered nonsuccedaneous?

a. Incisors
b. Canines
c. Premolars
d. Molars

Answer 129

d. Molars

Primary Molars → Premolars

Permanent molars grow on their own

Question 130

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 130

a. cementum overlaps enamel

Three possible types** of transitional interfaces may be present at the cementoenamel junction.: 1. **cementum may overlap the enamel** at the **cementoenamel junction**. 2. **cementum and enamel** may **meet end to end,** presenting no problems for either the clinician or patient. 3. a **gap may exist** **between** the **cementum and enamel, exposing dentin.

Question 131

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 131

b. The shedding of the associated

primary tooth is intermittent.

(irregular intervals)

Question 132

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 132

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 133

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 133

c. Ankyloglossia may be associated with

other craniofacial abnormalities.

Question 134

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 134

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 135

which of the following structures is not considered part of the periodontium?

a. alveolar process
b. cementum
c. basal bone
d. periodontal ligament

Answer 135

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 136

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 136

c. Odontoblastic layer

Question 137

Which of the following structures separates the epithelium from the connective tissue?

a. Submucosa
b. Basement membrane
c. Periosteum
d. Endosteum

Answer 137

b. Basement membrane

Question 138

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 138

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.

Question 139

which of the following terms correctly describes the alveolar bone proper?

a. lamina propria
b. cancellous bone
c. mucoperiosteum
d. cribriform plate

Answer 139

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 140

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 140

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 141

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 141

d. Epithelium

Question 142

Which of the following tissue types provides nutrition for the underlying compact bone?

a. Cartilage
b. Periosteum
c. Compact bone
d. Cancellous bone

Answer 142

b. Periosteum

Question 143

which of the following types of dental tissue provides vascular nutrition for the tooth’s cementum?

a. dentin
b. epithelial cells
c. periodontal ligament
d. alveolar process

Answer 143

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 144

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 144

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 final zone of pulp is the pulpal core, which is in the center of the pulp chamber.*

Question 145

which of these fiber groups does not have any cemental insertion?

a. interdental ligament
b. circular ligament
c. alveodental ligament
d. Interradicular group

Answer 145

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 146

which part of both of the jaws contains cancellous bone?

a. alveolar bone proper
b. cortical bone
c. interdental septum
d. alveolar crest

Answer 146

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 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 147

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 147

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 endpoints.*

Question 148

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 148

a. Dental sac

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

Question 149

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 149

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 150

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 150

a. Masseter muscle

Question 151

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 151

a. Bell stage

Initiation stage (6-7th week)

Bud stage (8th)

Cap stage (9-10th week)

Bell stage (11-12th week)

Question 152

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 152

a.

Maxillary incisors

Question 153

Which type of blood cell is directly responsible for immunoglobulin production?

a. Neutrophils
b. Basophils
c. Plasma cells
d. Mast cells

Answer 153

c. Plasma cells

lymphocytes = plasma cells

Question 154

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 154

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 155

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 155

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 156

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 156

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 157

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 157

The first statement is false

the second statement is true.

Question 158

______; the function of this membrane is to shape the root.

(A) Cervical Loop
(B) Hertwig Epithelial Root Sheath
(C) Cementocytes
(D) Cementogenesis

Answer 158

Hertwig Epithelial Root Sheath (HERS)

Question 159

_________ ________ is the main part of the anterior border of ramus that forms a concave forward curve

Answer 159

Coronoid notch

Question 160

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

Answer 160

Spina Bifida