MOSBY anA HYGIE

Question 1

1. Which paired muscle covers most of the lateral aspect
   of the ramus of the mandible?
   A. Temporalis
   B. Masseter
   C. Lateral pterygoid
   D. Medial pterygoid

Answer 1

ANS: B
The masseter (B) muscle is located on the lateral
aspect of the ramus of the mandible. The temporalis
(A) muscle is a large, fan-shaped muscle attached
to the coronoid process of the mandible. The lateral
pterygoid (C) has two heads and lies superiorly to the
medial pterygoid. The medial pterygoid (D) inserts on
the medial surface of the mandibular ramus. All these
muscles are muscles of mastication.

Question 2

2. During periodontal surgery, a fenestration is exposed
   on tooth #6. A fenestration is a defect of which type of
   bone?
   A. Compact
   B. Cancellous
   C. Interdental
   D. Interradicular

Answer 2

ANS: A
A fenestration is an opening or window in the solid
plate of compact (A) cortical bone on the facial
surface over the root of a tooth. Cancellous (B) bone
is located between the alveolar bone proper and the
plates of cortical bone. The interdental septum (C)
is bone located between the roots of adjacent teeth.
Interradicular (D) bone is located between the roots of
the same tooth

Question 3

3. The fibrous connective tissue membrane covering the
   outside of bone is called the
   A. endosteum.
   B. periosteum.
   C. hyaline cartilage.
   D. articular cartilage.

Answer 3

ANS: B
Periosteum (B) is the fibrous connective tissue
membrane covering the outside of bone except at the
articular surfaces. Endosteum (A) is the connective
tissue membrane lining the marrow cavity of the bone.
Hyaline cartilage (C) is a flexible and slightly elastic
cartilage found in joints, costal cartilages, the nasal
septum, the larynx, and the trachea. Articular cartilage
(D) is specialized, thin, smooth hyaline cartilage
found on the joint surfaces of bones, for example, in a
synovial joint.

Question 4

4. What is the purpose of the synovial membrane in a
   synovial joint?
   A. Secrete fluid into the joint cavity
   B. Surround the joint like a fibrous sleeve
   C. Innervate the muscles that move the joint
   D. Convey a sense of position and movement

Answer 4

ANS: A
The synovial membrane secretes synovial fluid (A),
which lubricates the synovial joint. The capsular
ligament surrounds the joint like a fibrous sleeve (B).
The sensory nerve endings innervate the muscles
that move the joint (C). Proprioceptive nerve endings
convey a sense of position and movement (D).

Question 5

5. Which component of a nerve conducts impulses
   toward the cell body?
   A. Axon
   B. Soma
   C. Neuron
   D. Dendrite

Answer 5

ANS: D
Dendrites (D) are branching cellular extensions of a
nerve that conduct impulses toward the cell. An axon
(A) is a cellular extension of a nerve that conducts
impulses away from the cell. The soma (B) is the body
of the cell containing the nucleus. A neuron (C) is the
basic functional unit of the nervous system.

Question 6

6. Which spinal vertebrae fuse together to form a
   triangular mass?
   A. Sacral
   B. Lumbar
   C. Cervical
   D. Thoracic

Answer 6

ANS: A
The sacral (A) vertebrae of the spinal cord fuse
together to form a triangular mass, called the
sacrum. The lumbar (B) region comprises the five
large vertebrae located between the thoracic and
sacral regions. The cervical (C) region comprises
the seven vertebrae located between the base of the
neck and the thoracic region. The thoracic (D) region
comprises the 12 vertebrae between the cervical and
lumbar regions

Question 7

7. The ophthalmic nerve is the first division of the fifth
   cranial nerve V, the trigeminal nerve. The maxillary
   nerve is the second division of the trigeminal nerve.
   A. Both statements are true.
   B. Both statements are false.
   C. The first statement is true, and the second statement
   is false.
   D. The first statement is false, and the second
   statement is true.

Answer 7

ANS: A
Both statements are true (A). Cranial nerve V is the
trigeminal nerve, of which the ophthalmic nerve
is the first division (V1
) and the maxillary nerve
is the second division (V2
). The third division of
the trigeminal nerve (V3
) is the mandibular nerve.
Choices B, C, and D do not accurately reflect the
statements.

Question 8

8. Which injections technique would be used to achieve
   anesthesia of teeth #15 and #16?
   A. Nasopalatine block
   B. Anterosuperior alveolar block
   C. Middle superior alveolar block
   D. Posterosuperior alveolar block

Answer 8

ANS: D
The posterosuperior alveolar block (D) anesthetizes
the mesiobuccal root of the first maxillary molar
and the second and third maxillary molars. The
nasopalatine block (A) anesthetizes the premaxillary
area of the palate and the anterior maxillary teeth.
The anterosuperior alveolar block (B) anesthetizes
the gingiva and the anterior maxillary teeth. The
middle superior alveolar block (C) anesthetizes
the premolars and the mesiobuccal root of the first
maxillary molar.

Question 9

10. All of the following are foramina in the sphenoid bone
    EXCEPT the
    A. incisive foramen.
    B. superior orbital fissure.
    C. foramen ovale.
    D. foramen rotundum.

Answer 9

ANS: A
The incisive foramen (A) is an opening to the incisive
canal in the palatine process of the maxilla. The
superior orbital fissure (B), foramen ovale (C), and
foramen rotundum (D) are all located in the sphenoid
bone and are exit points for cranial nerve V

Question 10

9. The infraorbital foramen is located in which bone?
   A. Frontal
   B. Maxilla
   C. Zygomatic
   D. Sphenoid

Answer 10

ANS: B
The infraorbital foramen passes through the maxilla
(B), not the frontal (A), zygomatic (C), or sphenoid
(D) bones.

Question 11

11. Which muscle retracts the tongue?
    A. Genioglossus
    B. Hyloglossus
    C. Styloglossus
    D. Palatoglossus

Answer 11

ANS: C
When the styloglossus (C) muscle contracts, the tongue
retracts. In contrast, the hyloglossus (B) will depress
the tongue upon contraction, and the genioglossus (A)
will protrude the tongue and depress portions. The
palatoglossus (D) elevates the base of the tongue, and
depresses the soft palate

Question 12

12. Which plane of dissection divides the body into
    anterior and posterior portions?
    A. Frontal
    B. Sagittal
    C. Horizontal
    D. Median

Answer 12

ANS: A
The frontal (A) plane divides the body into anterior
and posterior portions. The sagittal plane (B) divides
the body in an anteroposterior direction. The horizontal
plane (C) separates the body into superior and inferior
portions, and the median plane (D) divides the body
into equal right and left halves.

Question 13

13. Teeth #3 and #14 are
    A. ipsilateral to each other.
    B. contralateral to each other.
    C. inferior to each other.
    D. superficial to each other.

Answer 13

ANS: B
Teeth #3 and #14 are the first maxillary molars on the
opposite arches of the mouth, which means that they
are contralateral to each other (B). Ipsilateral (A)
would mean that they are on the same side. Inferior
(C) applies to a structure that is beneath or lower than
another structure, and superficial (D) applies to a
structure that is near the surface. These are not terms
used to describe the dentition.

Question 14

14. The following characteristics describe muscle tissue
    EXCEPT one. Which one is the EXCEPTION?
    A. Each muscle has two ends.
    B. Muscle cells are called sarcomeres.
    C. Muscles are categorized according to their role in
    movement.
    D. The muscle origin is attached to the least movable
    part.
    E. The muscle insertion is attached to the most
    movable part

Answer 14

ANS: B
The correct choice is B. Muscle cells are called
myocytes, whereas sarcomeres are the unit of contraction of the myofibrils of the muscle cell.
Muscles have two ends (A) and are categorized
according to their role in movement (C). The origin of
each muscle is defined by its least movable attachment
(D). In addition, the insertion is attached to the most
movable part (E)

Question 15

15. Which lymph nodes drain both sides of the chin, the
    lower lip, the floor of mouth, the apex of tongue, and
    the mandibular incisors?
    A. Facial
    B. Submental
    C. Submandibular
    D. Retropharyngeal

Answer 15

ANS: B
The submental (B) lymph nodes drain both sides of
the chin, the lower lip, the floor of mouth, the apex
of tongue, and the mandibular incisors. The facial
lymph nodes (A) are superficial nodes located along
the length of the facial vein and are further categorized
into four subgroups that drain the areas they are named
for: malar, nasolabial, buccal, and mandibular. The
submandibular nodes (C) drain the cheeks, the upper
lip, the body of the tongue, the anterior hard palate,
and all teeth except the mandibular incisors and the
maxillary third molars. The retropharyngeal lymph
nodes (D) drain the pharynx, the palate, the paranasal
sinuses, and the nasal cavity.

Question 16

16. Which endocrine gland matures T-lymphocytes for the
    immune system and undergoes involution (reduces in
    size) after puberty?
    A. Thyroid
    B. Thymus
    C. Pancreas
    D. Parathyroid

Answer 16

ANS: B
T-lymphocytes are processed in the thymus (B), where
they attain their mature function. The thymus is large
in infancy and shrinks after puberty. The thyroid
gland (A) produces two main hormones—thyroxine
(T4
) and triiodothyronine (T3
)—that circulate through
the bloodstream and have many effects on body
metabolism, growth, and development. The islet
cells of the pancreas (C) create and release important
hormones directly into the bloodstream. Two of the
main pancreatic hormones are insulin, which acts to
lower blood sugar, and glucagon, which acts to raise
blood sugar. Maintaining proper blood sugar levels
is crucial to the functioning of key organs, including
the brain, liver, and kidneys. The pancreas also has
an exocrine function in producing enzymes that aid
digestion. The parathyroid glands (D) regulate calcium
levels by secreting parathyroid hormone and calcitonin
into the bloodstream

Question 17

17. The corrugator supercilii is a muscle of facial
    expression in which region?
    A. Eye
    B. Nose
    C. Mouth
    D. Scalp

Answer 17

ANS: A
The corrugator supercilii is a muscle of facial
expression located just superior to the eye (A) and deep to the superior portion of the orbicularis oculi
muscle. The nose (B), mouth (C), and scalp (D) are not
moved by the corrugator supercilii muscle

Question 18

18. Which muscle elevates the mandible?
    A. Risorius
    B. Buccinator
    C. Medial pterygoid
    D. Lateral pterygoid

Answer 18

ANS: C
Upon contraction, the medial pterygoid (C) elevates
the mandible. The risorius (A) stretches the lips
by pulling each labial commissure laterally. The
buccinator (B) compresses the cheeks during chewing
by retracting the labial commissure. The lateral
pterygoid (D) depresses, protrudes, and deviates the
mandible laterally.

Question 19

19. Which muscle originates from the alveolar process of
    the maxilla, the alveolar process of the mandible, and
    the pterygomandibular raphe?
    A. Masseter
    B. Risorius
    C. Buccinator
    D. Sternocleidomastoid

Answer 19

ANS: C
The buccinator (C) muscle is a thin, quadrilateral muscle
originating from the three areas listed above. The masseter
(A) originates from the zygomatic arch; the risorius (B)
originates from a fascia superficial to the masseter muscle;
and the sternocleidomastoid (D) originates from the
clavicle.

Question 20

20. Which part of the brain regulates homeostasis?
    A. Medulla
    B. Thalamus
    C. Cerebellum
    D. Hypothalamus

Answer 20

ANS: D
The hypothalamus (D) regulates homeostasis in
the body. The medulla (A) is part of the brain stem
and is involved in regulating the components of
the autonomic nervous system. The thalamus (B)
plays a major role in relaying nerve impulses. The
cerebellum (C) is responsible for the coordination of
voluntary movements and for maintaining posture
and balance.

Question 21

21. Which branch of the trigeminal nerve contains both
    sensory and motor components?
    A. Ophthalmic V1
    B. Maxillary V2
    C. Mandibular V3

Answer 21

ANS: C
The mandibular or third division of the fifth cranial
nerve V3
(C), or the trigeminal nerve, has both afferent
or sensory and efferent or motor components. The
afferent component provides sensation to the teeth
and tissues of the mandible and the anterior two thirds
of the tongue. The efferent component innervates the
muscles of mastication, tensor tympani, and tensor veli
palatini. The ophthalmic V1
(A), or the first division
of the trigeminal nerve, provides sensation to the
conjunctivae, cornea, eyeball, orbit, forehead, ethmoid
and frontal sinuses, and part of the dura mater. The
second branch of the trigeminal nerve, maxillary V2
(B), carries sensory information for the maxillae and overlying skin, maxillary sinuses, nasal cavity, palate,
nasopharynx, and part of the dura mater.

Question 22

22. Which of the following are the two main divisions or
    systems of the autonomic nervous system?
    A. Brain, spinal cord
    B. Afferent impulse, efferent impulse
    C. Sympathetic system, parasympathetic system

Answer 22

ANS: C
Sympathetic and parasympathetic (C) systems are the
two divisions of the autonomic nervous system. The
brain and the spinal cord (A) are structures within the
central nervous system. Afferent impulse is the sensory
nerve impulse traveling toward the central nervous
system, and efferent impulse is the motor nerve impulse
traveling to the muscles that will move in response (B).

Question 23

23. Which cranial nerve provides parasympathetic innervation
    to the cardiac muscles, thymus, and stomach?
    A. IV
    B. X
    C. XI
    D. XII

Answer 23

ANS: B
Cranial nerve X (B), the vagus nerve, sends
parasympathetic fibers to many organs, including the
thymus and the muscles of the heart and stomach.
Cranial nerve IV (A), the trochlear nerve, serves as an
efferent nerve for a muscle of the eye. Cranial nerve
XI (C), the accessory nerve, serves as an efferent nerve
for various muscles of the head and neck. Cranial
nerve XII (D), the hypoglossal nerve, innervates
intrinsic and extrinsic muscles of the tongue.

Question 24

24. Which of the following is NOT innervated by the
    middle superior alveolar nerve?
    A. Tooth #4
    B. Tooth #12
    C. Distobuccal root of tooth #2
    D. Mesiobuccal root of tooth #14

Answer 24

ANS: C
The distobuccal root of the maxillary second molar,
tooth #2 (C), is innervated by the posterosuperior
alveolar nerve, not the middle superior alveolar
nerve. The middle superior alveolar nerve innervates
maxillary premolars, teeth #4 and #5 (A) and, #12 and
#13 (B), and the mesiobuccal root of maxillary first
molars, teeth #3 and #14 (D).

Question 25

25. The muscles of facial expression are innervated by which nerve? A. IV B. V C. VII D. VIII

Answer 25

ANS: C Cranial nerve VII (C), the facial nerve, innervates the muscles of facial expression. Cranial nerve IV (A), the trochlear nerve, serves as an efferent nerve for a muscle of the eye. Cranial nerve V (B), the trigeminal nerve, serves as an afferent nerve to the oral cavity, teeth, and most of the skin of the face and head, as well as efferent innervations for the muscles of mastication and some of the muscles of the palate. Cranial nerve VIII (D), the vestibulocochlear nerve, is an afferent nerve for hearing and balance

Question 26

26. Which vein receives blood flow from the superficial temporal vein and the facial vein and drains into the external jugular vein? A. Maxillary B. Ophthalmic C. Inferior alveolar D. Retromandibular

Answer 26

ANS: D The retromandibular (D) vein receives blood flow from the superficial temporal vein and the facial vein and drains into the external jugular vein. It is situated immediately posterior to the angle of the mandible. The maxillary vein (A) receives blood flow from the pterygoid plexus and drains into the retromandibular vein. The ophthalmic vein (B) drains the tissue of the orbit and proceeds into the facial vein. The inferior alveolar vein (C) forms from the merging of the dental, alveolar, and mental branches and drains into the pterygoid plexus

Question 27

27. The articulation of the temporomandibular joint involves which two bones? A. Temporal bone, mental protuberance B. Sphenoid bone, coronoid process of the mandible C. Temporal bone, mandibular condyles

Answer 27

ANS: C Temporal bone and mandibular condyle (C) articulate to form part of the temporomandibular joint. Neither temporal bone and mental protuberance (A) nor sphenoid bone and the coronoid process of the mandible (B) articulate with each other

Question 28

28. Which artery supplies the mandibular teeth and surrounding tissues with blood? A. Facial B. Lingual C. Inferior alveolar D. Pterygoid plexus

Answer 28

ANS: C The inferior alveolar artery (C) is a branch of the maxillary artery and supplies the mandibular teeth, the floor of the mouth, and the mental region with blood. The facial artery (A) is also known as the external maxillary artery and extends to the mid-face region to supply the oral, buccal, zygomatic, nasal, infraorbital, and orbital regions. The lingual artery (B) is an anterior branch from the external carotid artery and supplies the tissue superior to hyoid bone, including the suprahyoid muscles and the floor of the mouth. The pterygoid plexus (D) supplies the deep facial areas and the posterosuperior alveolar vein and the inferior alveolar vein.

Question 29

29. Which major artery supplies the brain with blood and is palpated during emergency situations? A. Aorta B. Subclavian C. Internal carotid D. Common carotid

Answer 29

ANS: D The common carotid artery (D) runs superiorly along the neck, lateral to the trachea and the larynx. When palpated against the larynx, the most reliable arterial pulse of the body can be monitored. The aorta (A) is a major artery, which gives rise to the common carotid artery and the subclavian artery (B) on the left side of the heart and the brachiocephalic artery on the right side of the heart. The internal carotid artery (C) supplies the anterior part of the brain and the eye and sends branches to the forehead and the nose. The aorta (A), the subclavian artery (B), and the internal carotid artery (C) cannot be reliably palpated in an emergency.

Question 30

30. Which artery is the source of the ophthalmic artery, has NO branches, and is located deep to the sternocleidomastoid muscle? A. Aorta B. Subclavian C. External carotid D. Internal carotid

Answer 30

ANS: D The internal carotid artery (D) is a branchless division of the common carotid artery, which is covered by the sternocleidomastoid muscle, and supplies blood to the ophthalmic artery. The aorta (A), a major artery that is a portion of the heart itself gives rise to the common carotid artery and the subclavian artery (B) on the left side of the heart and the brachiocephalic artery on the right side of the heart. The external carotid artery (C) travels superiorly to the internal carotid artery and has four sets of branches.

Question 31

31. The facial artery is a direct branch of which main artery? A. Subclavian B. Internal carotid C. External carotid D. Brachiocephalic

Answer 31

ANS: C The facial artery is the final anterior branch from the external carotid artery (C), not the subclavian artery (A), the internal carotid artery (B), or the brachiocephalic artery (D).

Question 32

33. The facial vein drains each region of the head and neck EXCEPT one. Which one is the EXCEPTION? A. Orbital region B. Upper lip area C. Lower lip area D. Submental region

Answer 32

ANS: A The orbital region (A) is drained by the cavernous sinus and the pterygoid plexus, not the facial vein. The facial vein drains the upper lip (B), the lower lip (C), and the submental region (D).

Question 33

32. Which of the following arteries supplies maxillary anterior teeth with blood? A. Incisive B. Mylohyoid C. Greater palatine D. Anterior superior alveolar

Answer 33

ANS: D Maxillary anterior teeth are supplied by the anterosuperior alveolar artery (D). The incisive artery (A) supplies the periodontium of the mandibular anterior teeth, including the associated gingiva. The mylohyoid artery (B) supplies the floor of the mouth and the mylohyoid muscle. The greater palatine artery (C) supplies the hard and soft palates.

Question 34

34. Veins of teeth have alveolar branches and dental branches. Which branch type would drain the pulp tissue of teeth through the apical foramen? A. Alveolar branches B. Dental branches C. Both A and B D. Neither A nor B

Answer 34

ANS: B The incisive artery branches off the inferior alveolar artery, remaining within the mandibular canal to divide into dental and alveolar branches. The dental branches (B) of the pulp drain the mandibular anterior teeth by way of each tooth’s apical foramen. The alveolar branches (A) of the periodontium drain the mandibular anterior teeth, including the gingiva. Choices C and D do not correctly address the statement.

Question 35

35. Which vein has NO valves, drains most of the head and neck region, and does NOT drain any of the dentition? A. Internal jugular B. External jugular C. Internal maxillary D. Inferior alveolar

Answer 35

ANS: A The internal jugular vein (A) drains most of the head and the neck, except the dentition. The external jugular vein (B) is the only vein the head and neck with valves. The internal maxillary vein (C) drains the pterygoid plexus, whereas the inferior alveolar vein (D) drains the mandibular teeth and the periodontium

Question 36

36. Many veins in the head and neck region lack valves. Valveless veins of the head and neck contribute to the severe and rapid spread of dental infections. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 36

ANS: A The correct choice is A; both statements are true. Most veins in the head and neck lack valves, with the exception of the external jugular vein. The lack of valves in the veins of the head and neck may contribute to severe and rapid spread of dental infections. Choi

Question 37

37. Each of the following is an afferent cranial nerve EXCEPT one. Which one is the EXCEPTION? A. Optic B. Vagus C. Olfactory D. Hypoglossal

Answer 37

ANS: D The hypoglossal nerve (D) is an efferent (motor) cranial nerve for both intrinsic and extrinsic muscles of the tongue. The optic nerve (A), the vagus nerve (B), and the olfactory nerve (C) are afferent, or sensory, nerves.

Question 38

38. Which muscle, upon contraction, protrudes the tongue? A. Genioglossus B. Hyloglossus C. Styloglossus

Answer 38

ANS: A The genioglossus muscle (A) protrudes the tongue upon contraction. The hyloglossus muscle (B) depresses the tongue when it contracts. Upon contraction, the styloglossus muscle (C) retracts the tongue.

Question 39

39. Each of the following is a suprahyoid muscle EXCEPT one. Which one is the EXCEPTION? A. Mylohyoid B. Geniohyoid C. Stylohyoid D. Sternohyoid

Answer 39

ANS: D The sternohyoid muscle (D) is an infrahyoid muscle. The mylohyoid (A), geniohyoid muscle (B), and stylohyoid (C) muscles are all suprahyoid muscles.

Question 40

40. Cervical lymph nodes run along which muscle? A. Trapezius B. Buccinator C. Epicranial D. Sternocleidomasto

Answer 40

ANS: D The sternocleidomastoid muscle (D) is a landmark of the neck during the extraoral examination to define locations of superficial and deep cervical lymph nodes. Cervical lymph nodes do not lie adjacent to the trapezius (A), buccinator (B), or epicranial (C) muscles

Question 41

Muscles of Facial Expression: 1. Mentalis 2. Risorius 3. Corrugator supercilii 4. Levator anguli oris 5. Buccinator ----------- Facial Expression upon Contraction of Muscle: A. Frowning B. Raising chin and protruding lower lip C. Chewing D. Stretching lips E. Smiling

Answer 41

For each numbered muscle, select the most closely linked facial expression from the list provided. ANS: 1B; 2D; 3A; 4E; 5C When the mentalis muscle (1) contracts, the chin is raised and the lower lip protrudes (B). When the risorius muscle (2) contracts, the lips are stretched (D). When the corrugator supercilii (3) contracts, this action produces a frown (A). When the levator anguli oris (4) contracts, this action produces a smile (E). When the buccinator (5) contracts, food is pushed onto the occlusal plane, facilitating the chewing of food (C).

Question 42

42. For each numbered structure, select the most closely linked primary nodes that drain those structures from the list provided. Anatomic Structure: 1. Sublingual salivary gland 2. Parotid salivary gland 3. Base of tongue 4. Paranasal sinus 5. Lower lip ------------- Lymph Node Drainage: A. Deep parotid B. Submandibular C. Superior deep cervical D. Submental E. Retropharyngeal

Answer 42

For each numbered structure, select the most closely linked primary nodes that drain those structures from the list provided. ANS: 1B; 2C; 3E; 4A; 5D The sublingual salivary gland (1) is drained by the submandibular lymph node (B). The parotid salivary gland (2) is drained by the superior deep cervical lymph node (C). The base of the tongue (3) is drained by the retropharyngeal lymph node (E). The paranasal sinus (4) is drained by the deep parotid lymph node (A). The lower lip (5) is drained by the submental lymph node (D).

Question 43

For each numbered temporomandibular joint (TMJ) disk position, select the most closely linked description of the movement from the list provided TMJ Disk Positions: 1. Elevation 2. Lateral deviation 3. Retraction 4. Protrusion 5. Depression ----------------- Movement: A. Shifting the mandible to one side by unilateral contraction of the lateral pterygoid muscle B. Opening the mouth by contraction of the inferior heads of the lateral pterygoid muscles and the suprahyoid muscles C. Moving the jaw forward by bilateral contraction of the lateral pterygoid muscles D. Raising the lower jaw by contraction of all portions of the temporalis, masseter, and medial pterygoid muscles E. Moving the jaw back by contraction of the posterior portions of both temporalis muscles

Answer 43

ANS: 1D; 2A; 3E; 4C; 5B Elevation of the TMJ disk (1) results in the raising of the lower jaw through contraction of all portions of the temporalis, masseter, and medial pterygoid muscles (D). Lateral deviation of the TMJ disk (2) results in shifting of the mandible to one side via unilateral contraction of the lateral pterygoid muscle (A). Retraction of the TMJ disk (3) results in backward jaw movement through contraction of posterior portions of both temporalis muscles (E). Protrusion of the TMJ disk (4) produces forward jaw movement through bilateral contraction of the lateral pterygoid muscles (C). Depression of the TMJ disk (5) produces opening of the mouth through contraction of the inferior heads of the lateral pterygoid and suprahyoid muscles (B).

Question 44

45. Each of the following is a period of prenatal development EXCEPT one. Which one is the EXCEPTION? A. Fetal B. Ovulation C. Embryonic D. Preimplantation

Answer 44

ANS: B The ovulation period (B) occurs during a woman’s menstrual cycle with the release of an ovum. The unfertilized egg is not part of prenatal development. The three distinct periods of prenatal development are the preimplantation period (D), occurring during the first week after fertilization; the embryonic period (C), occurring during the second to the eighth week; and the fetal period (A), which occurs from the third to the ninth month.

Question 45

44. The first branchial arch is also called the mandibular arch. The cartilage forming within the mandibular arch is known as Reichert cartilage. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 45

ANS: C Choice C is correct; the first statement is true, and the second statement is false. There are six branchial arches. The first branchial arch is considered the mandibular arch, and the second branchial arch is known as the hyoid arch. The cartilage that forms within the mandibular arch is Meckel cartilage, not Reichert cartilage, which forms in the second branchial arch. Choices A, B, and D do not correctly reflect the statements.

Question 46

46. Which cells are responsible for producing dentin? A. Osteoblasts B. Ameloblasts C. Odontoblasts D. Cementoblasts

Answer 46

ANS: C Odontoblasts (C) are responsible for producing dentin. Osteoblasts (A) are bone-producing cells. Ameloblasts (B) produce enamel and cementoblasts (D) produce cementum

Question 47

47. Each of the following is a component of the tooth germ EXCEPT one. Which one is the EXCEPTION? A. Enamel organ B. Dental sac C. Dental lamina D. Dental papilla E. Dental follicle

Answer 47

ANS: C The dental lamina (C) is not part of the tooth germ, although the proliferation of ectodermal cells into specific sites is the first stage of odontogenesis. This thickened sheet of epithelium will give way to become the enamel organ. The three components that make up the tooth germ are the enamel organ (A), the dental sac (B), and the dental papilla (D). DENTAL FOLLICLE (E) is another term for dental sac.

Question 48

48. Order the stages of odontogenesis. Match each letter with its proper sequence number. ___ A. Cap stage ___ B. Bud stage ___ C. Bell stage ___ D. Maturation stage ___ E. Initiation stag

Answer 48

ANS: 1E; 2B; 3A; 4C; 5D Odontogenesis begins with the initiation stage (1E) during the sixth to the seventh week. Next is the bud stage (2B), beginning in the eighth week, which is followed by the cap stage (3A) during weeks nine and ten. During the eleventh and twelfth weeks, the bell stage (4C) occurs, and the final stage of odontogenesis is the maturation stage (5D).

Question 49

49. Division of a cell into two daughter cells occurs during which phase of mitosis? A. Prophase B. Anaphase C. Metaphase D. Telophase

Answer 49

ANS: D Telophase (D) is the last phase in which the individual cell divides into two daughter cells. During prophase (A), the DNA (deoxyribonucleic acid) in the form of chromatin condenses into chromosomes. During metaphase (C), the chromosomes move and align themselves in the middle of the cell. Next is anaphase (B), during which the chromosomes separate and migrate to opposite poles of the cell.

Question 50

50. The inner cells of the dental papilla will develop into which structure? A. Cementum B. Dentin C. Pulp D. Enamel

Answer 50

ANS: C The inner cells of the dental papilla develop into dental pulp (C). Cementum (A) is produced by cementocytes that come from the dental sac. Dentin (B) is produced by the outer cells of the dental papilla. Enamel (D) is produced by ameloblast cells that come from the enamel organ.

Question 51

51. The earliest indication of a part or an organ during prenatal development is referred to as the A. primordium. B. stomodeum. C. zygote. D. nucleus.

Answer 51

ANS: A The primordium (A) is the earliest indication of a part or an organ during prenatal development. The stomodeum (B) is also known as the primitive mouth and begins as just a slight depression but subsequently will give rise to the oral cavity. A zygote (C) is a fertilized egg, resulting from the union of a man’s sperm and a woman’s ovum. A nucleus (D) is a large organelle found in most cells, responsible for the regulation of all cellular function

Question 52

53. Which stage of tooth development occurs between the 11th and 12th weeks of prenatal development? A. Bud B. Cap C. Bell D. Initiation

Answer 52

ANS: C The bell stage (C) occurs between weeks 11 and 12 of prenatal development. The initiation stage (D) occurs between weeks 6 and 7 of tooth development. The bud stage (A) occurs during week 8, whereas the cap stage (B) happens between weeks 9 and 10.

Question 53

54. Which of the following cells is/are DIRECTLY responsible for immunoglobulin production? A. Plasma B. Basophils C. Monocytes D. Neutrophils E. Eosinophils

Answer 53

ANS: A Activated B-cell lymphocytes form plasma cells (A), which are directly responsible for producing immunoglobulins (antibodies). Basophils (B), monocytes (C), neutrophils (D), and eosinophils (E) are all white blood cells, and all contribute to the immune response. A lymphocyte is a white blood cell that has three functional types, one of which is a B-cell lymphocyte.

Question 54

52. Which primordial structure differentiates into the ameloblasts that produce enamel? A. Outer enamel epithelium B. Stellate reticulum C. Inner enamel epithelium D. Stratum intermedium

Answer 54

ANS: C Inner enamel epithelium (IEE) (C) comprises the columnar cells of the enamel organ that differentiate into ameloblasts. The outer enamel epithelium (OEE) (A) comprises cuboidal cells that protect the outer portion of the enamel organ. Between the IEE and OEE is the stellate reticulum (B), composed of star-shaped cells, and the stratum intermedium (D), composed of flat to cube-shaped cells; both support the production of enamel.

Question 55

55. Incremental lines that stain brown in preparations of mature enamel are A. neonatal lines. B. enamel tufts. C. lines of Retzius.

Answer 55

ANS: C Incremental lines that stain brown in preparations of mature enamel are lines of Retzius (C). The neonatal line (A) is an incremental line of Retzius; however, it is more pronounced and marks trauma or stress placed on ameloblasts during birth. Enamel tufts (B) appear as small, dark hypocalcified, brushlike areas found near the dentinoenamel junction (DEJ). Enamel spindles (D) are actually short dentinal tubules that have been trapped in the enamel matrix. Enamel lamellae (E) extend from the DEJ all the way out to the occlusal surface and are partially calcified sheets of enamel matrix

Question 56

56. Which period of prenatal development occurs during months 3 to 9? A. Fetal B. Embryonic C. Preimplantation D. A only E. Both A and B

Answer 56

ANS: A The final period of prenatal development is the fetal period (A), which spans months 3 to 9 or delivery. After fertilization, the zygote travels along until it implants itself into the uterus. This period is known as the PREIMPLANTATION PERIOD (C), which occurs during week 1. The embryonic period (B) follows during weeks 2 through 8. Choices D and E do not correctly address the statement.

Question 57

58. Each cell facilitates the exfoliation of a primary tooth EXCEPT one. Which one is the EXCEPTION? A. Ameloblast B. Osteoclast C. Odontoclast D. Cementoclast

Answer 57

ANS: A The ameloblast (A) is the enamel-producing cell that does not facilitate exfoliation of teeth. The osteoclast (B) is necessary to resorb the alveolar bone anchoring the tooth. The odontoclast (C) is responsible for resorption of dentin. The cementoclast (D) is responsible for the resorption of cementum

Question 58

57. From the following list, select the structures of the embryo that begin development in week 4 of prenatal development. A. Face B. Neck C. Palate D. Tongue E. Placenta

Answer 58

ANS: A, B, D Facial development (A) begins during week 4 and continues into week 12. The neck (B) and the tongue (D) begin to develop in conjunction with the face. The placenta (E) begins development during week 2 from the interaction of the trophoblast layer and the endometrial tissues. The palate (C) begins formation during week 5 and also continues through week 12.

Question 59

60. Down syndrome is a developmental disturbance that occurs during which period of prenatal development? A. Fetal B. Embryonic C. Preimplantation

Answer 59

ANS: C Down syndrome is a developmental disturbance that occurs during meiosis. The final stages of meiosis occur just after fertilization, which takes place during the preimplantation (C) period. The division of chromosomes occurs prior to the zygote being implanted and has already taken place by the embryonic (B) or fetal (A) periods.

Question 60

59. The cervical loop is responsible for development of A. dentin. B. pulp. C. enamel. D. root.

Answer 60

ANS: D The cervical loop is responsible for root (D) development. Dentin (A) is developed from odontoblasts. Pulp (B) develops from the inner cells of the dental papilla. The enamel of the crown of the tooth (C) is formed from ameloblasts.

Question 61

61. The incomplete developmental division of a tooth germ is called FUSION. Fusion takes place during the initiation stage of tooth development. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true

Answer 61

ANS: B Both statements are false (B). Fusion is the union of two tooth germs. Incomplete tooth germ division is referred to as GEMINATION. Fusion takes place during the cap stage of odontogenesis, not during the initiation stage. Choices A, C, and D do not accurately reflect the statements.

Question 62

62. Which is the most common cell found in the lamina propria of the oral mucosa? A. Epiblast B. Odontoblast C. Osteoblast D. Osteoclast E. Fibroblast

Answer 62

ANS: E The fibroblast (E) is the most common cell found in the lamina propria of the oral mucosa. Epiblast (A) layers are high-columnar cells of the bilaminar embryonic disk. The odontoblast (B) is the cell that will produce dentin. The osteoblast (C) is a bone-forming cell, and the osteoclast (D) is a bone￾resorbing cell.

Question 63

63. The cells responsible for the development of the periodontal ligament come from the A. dental sac. B. dental papilla. C. enamel organ. D. successional lamellae

Answer 63

ANS: A The dental sac or follicle (A) consists of ectomesenchyme that surrounds the enamel organ and will produce not only the periodontal ligament but also cementum and alveolar bone. The dental papilla (B) has inner cells that will produce the pulp and outer cells that will produce dentin. The enamel organ (C) will produce enamel. The successional lamellae (D) comprise the epithelial tissue that will give rise to succedaneous teeth.

Question 64

64. The cusp of Carabelli is found on which permanent molars? A. #3, #14 B. #2, #15 C. #19, #30 D. #18, #31

Answer 64

ANS: A The cusp of Carabelli is found on the lingual surface of maxillary first molars, which includes #3 and #14 (A). Teeth #2 and #15 (B) are maxillary second molars; #19 and #30 (C) are mandibular first molars; and #18 and #31 (D) are mandibular second molars.

Question 65

65. Eight bones compose the neurocranium, surrounding the brain. Fifteen bones compose the viscerocranium, or the bones of the face. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 65

ANS: C The correct answer is (C); the first statement is true, and the second statement is false. Eight bones compose the neurocranium: the frontal, the sphenoid, the ethmoid, and the occipital bones, which are single bones. The paired temporal and parietal bones also are part of the neurocranium. The second statement is false. There are 14 bones, not 15, that make up the viscerocranium, including the single mandible and the vomer. The paired nasal, lacrimal, zygomatic, inferior nasal conchae, palatine, and maxillae are the remaining bones composing the face. Choices A, B, and D do not accurately reflect the statements.

Question 66

66. The sphenoid bone is composed of the A. palatine process. B. temporal fossa. C. superior orbital fissure of the orbit. D. base of skull anterior to occipital bone. E. B, C, and D.

Answer 66

ANS: E The correct answer is (E). The complex, three￾dimensional sphenoid bone contains the temporal fossa (B), the superior orbital fissure (C), the base of the skull anterior to occipital bone (D), and the pterygoid processes. The palatine process (A) is part of the maxillae.

Question 67

67. Anatomically, the inferior alveolar artery supplies which structure? A. Soft floor of mouth B. Tongue muscles C. Sublingual gland D. Mandibular teeth

Answer 67

ANS: D The mandibular teeth (D) and the bone of the mandible are supplied by the inferior alveolar artery. The lingual artery supplies the floor of the mouth (A), and its branches supply the tongue (B). The sublingual gland (C) is supplied by the sublingual and submental arteries

Question 68

68. The functions of the lymphatic system include all EXCEPT one. Which one is the EXCEPTION? A. Filter fluids B. Fight infection C. Produce lymphocytes D. Produce thrombocytes E. Return plasma to venous bloodstream

Answer 68

ANS: D The correct choice is D; thrombocytes are produced in bone marrow and not in the lymphatic system. The lymphatic system filters fluids (A), fights infection (B), produces lymphocytes (C), and returns plasma to the venous bloodstream (E).

Question 69

For each division of the trigeminal nerve (V) listed, select its appropriate name from the list provided.

Answer 69

ANS: 1C; 2A; 3B Division I (1) is known as the ophthalmic V1 (C). Division II (2) is the maxillary V2 (A). Division III (3) is the mandibular V3 (B).

Question 70

The abducens (VI), trochlear (IV), and oculomotor (III) nerves all provide innervation to the muscles of the eye. These nerves provide sensory innervation

Answer 70

ANS: C The correct choice is C. The first statement is true, and the second statement is false. The abducens, trochlear, and oculomotor nerves supply motor innervation to the muscle of the eye. Choices A, B, and D do not correctly reflect the statements

Question 71

71. Match each germ layer listed to the structure it forms in the developing embryo. Germ Layer Structure Formed in Embryo ____ 1. Endoderm A. Gastrointestinal tract, epithelium, and associated glands ____ 2. Mesoderm B. Nervous system, epidermis, sensory epithelium of the eye, ear, and nose; tooth enamel; and oral epithelium ____ 3. Ectoderm C. Muscles, bone, cartilage, blood, dentin, pulp, cementum, and periodontal ligament

Answer 71

ANS: 1A; 2C; 3B The endoderm (1) forms the gastrointestinal tract, epithelium, and associated glands (A). The mesoderm (2) forms muscles, bone, cartilage, blood, dentin, pulp, cementum, and periodontal ligament (C). The ectoderm (3) forms the nervous system, epidermis, sensory epithelium of the eye, ear, and nose; the tooth enamel; and the oral epithelium (B).

Question 72

Match each cell type to the structure it forms Developing Branchial Arch: ___ 1. Mandibular arch (branchial I) ____ 2. Hyoid arch (branchial II) ____ 3. Branchial arch III ____ 4. Branchial arch IV --------------- Resulting Structure: A. Muscles of facial expression, cranial nerve VII B. Tongue, cranial nerve IX C. Muscles of throat, inferior hyoid cartilage, cranial nerve X D. Mandible, muscles of mastication, cranial nerve V

Answer 72

ANS: 1D; 2A; 3B; 4C Ameloblasts (1) give rise to enamel (D). Cementoblasts (2) give rise to cementum (A). Odontoblasts (3) give rise to dentin (B). The dental follicle (4) gives rise to mesenchymal cells, which give rise to alveolar bone (C), the periodontal ligament, and cementum.

Question 73

For each of the developing branchial arches listed, select the most appropriate anatomic structure that it gives rise to. Cell Type: ____ 1. Ameloblasts ____ 2. Cementoblasts ____ 3. Odontoblasts ____ 4. Dental follicle --------------- Resulting Structure: A. Cementum B. Dentin C. Alveolar bone D. Enamel

Answer 73

ANS: 1D; 2A; 3B; 4C The mandibular arch (1) gives rise to the mandible, muscles of mastication, and cranial nerve V (D). The hyoid arch (2) gives rise to the muscles of facial expression and cranial nerve VII (A). Branchial arch III (3) gives rise to the tongue and cranial nerve IX (B). Branchial arch IV (4) gives rise to the muscles of the throat, the inferior hyoid cartilage, and cranial nerve X (C).

Question 74

76. A hematoma that results from the administration of a posterior superior alveolar (PSA) nerve block is caused by bleeding from which arteries or veins? 1. Posterior superior alveolar artery 2. Pterygoid plexus of veins 3. Temporal artery 4. Facial artery 5. Maxillary vein 6. Posterior retromandibular vein A. 1, 2, 5 B. 2, 3, 4 C. 3, 4, 6 D. 1, 2, 4

Answer 74

ANS: D The posterior superior alveolar artery (1), the pterygoid plexus of veins (2) and the facial artery (4) are located in the infratemporal fossa. This location may contain a high volume of blood if a hematoma occurs. The vessels listed in A, B, and C are not associated with the PSA nerve block.

Question 75

74. The temporomandibular joint (TMJ) is capable of which two types of movement? A. Rotation, gliding B. Hinge, translation C. Pivot, ball and socket D. Ball and socket, saddle

Answer 75

ANS: A The temporomandibular joint (TMJ) rotates and glides (A). Rotational movement occurs between the disk and the mandibular condyle in the lower synovial cavity. As the jaw opens further, an anterior gliding movement also occurs along the posterior slope of the articular eminence. Movements B, C, and D are not associated with the TMJ.

Question 76

75. Which arteries are the terminal branches of the external carotid artery? A. Superior thyroid, lingual B. Facial, ascending pharyngeal C. Posterior auricular and occipital D. Maxillary, superficial temporal

Answer 76

ANS: D There are approximately eight main branches of the external carotid artery. The terminal branches are maxillary and superficial temporal branches (D) given off deep to the neck of the condyle. The superior thyroid and lingual (A) branches and the facial and ascending pharyngeal (B) branches are given off in the carotid triangle. The posterior auricular and occipital (C) arteries are posterior arteries given off below maxillary and superficial temporal arteries.

Question 77

77. How many teeth are present in an individual with a full deciduous dentition? A. 20 B. 24 C. 28 D. 32

Answer 77

ANS: A The full deciduous dentition contains 20 teeth (A). The full permanent dentition contains 32 teeth (D). Neither 24 (B) nor 28 (C) represents a full count of teeth at any stage.

Question 78

78. Which is NOT a characteristic feature of the primary dentition? A. Thin enamel B. Thin dentin C. Large pulp cavity D. Whiter in color than permanent dentition

Answer 78

ANS: B Dentin in primary teeth is much thicker than dentin in permanent teeth (B). Primary teeth are characterized as having relatively thin enamel (A) and large pulp cavities (C) and are whiter in color than permanent teeth (D).

Question 79

79. Which teeth have wider crowns mesiodistally than faciolingually? A. #5 and #12 B. #7 and #10 C. #24 and #25 D. #23 and #26

Answer 79

ANS: B Permanent maxillary incisors, teeth #7 and #10 (B), are wider mesiodistally than faciolingually. Maxillary premolars (A) and mandibular incisors (C and D) are wider faciolingually than mesiodistally

Question 80

80. Each is an important function of the cementoenamel junction (CEJ) EXCEPT one. Which one is the EXCEPTION? A. Prevention of caries B. Self-cleansing properties C. Food deflection resulting in gingival inflammation D. Health and maintenance of periodontal tissue in interproximal spaces

Answer 80

ANS: A Prevention of caries decay (A) is NOT a function of the cementoenamel junction (CEJ). The CEJ functions for self-cleansing by the natural spillways that are formed, lending to self-cleansing properties (B), food deflection (C), and both health and maintenance of periodontal tissues in the interproximal spaces (D).

Question 81

Match each dental anomaly listed with its description. Dental Anomaly: ____ 1. Dwarf roots ____2. Concrescence ____3. Dilaceration ____ 4. Mulberry molars ____ 5. Gemination ____ 6. Dens in dente ------------------------- Description: A. Partial splitting of tooth germ B. Crown or root demonstrating sharp bends, curves C. Fusion after root formation D. Extreme condition impacting crown-to-root ratio E. Result of congenital syphilis F. Tooth within a tooth

Answer 81

ANS: 1D; 2C; 3B; 4E; 5A; 6F Dwarf roots (1) affect the crown-to-root ratio (D). Concrescence (2) involves fusion after roots are formed (C). In dilaceration (3), the crown or root demonstrates sharp bends or curves (B). Mulberry molars (4) result from congenital syphilis (E). Gemination (5) involves the partial splitting of the root germ (A). Dens in dente (6) describes a tooth within a tooth (F).

Question 82

82. The clinical crown-to-root ratio is always the same. However, the anatomic crown–to-root ratio may change. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 82

ANS: B Both statements are false (B). The clinical crown-to￾root ratio may change, depending on the location of alveolar bone and the gingiva. The anatomic crown–to￾root ratio (the crown and root are covered with enamel and cementum, respectively) always remains the same. Choices A, C, and D do not correctly reflect the statements.

Question 83

83. There is relatively constant mesial movement of the molars to compensate for proximal abrasion. Relatively consistent occlusal forces result in bone remodeling. A. Both statements are correct and related. B. Both statements are correct but NOT related. C. The first statement is correct, but the second is NOT. D. The first statement is NOT correct, but second is correct. E. Both statements are incorrect and unrelated.

Answer 83

ANS: A Both statements are correct and related (A). Active eruption, mesial drift, and masticatory occlusal and orthodontic corrective forces are all examples of consistent forces in alveolar bone remodeling. Traumatic occlusal force is an example of a type of force that is NOT a consistent, constant force that results in bone remodeling. Choices B, C, D, and E do not correctly reflect the statements.

Question 84

85. Cellular metabolism occurs in the A. ribosomes. B. lysosome. C. mitochondria. D. Golgi apparatus. E. endoplasmic reticulum.

Answer 84

ANS: C Mitochondria (C) are the “power plants” of the cell and are responsible for the rate of energy production. Ribosomes (A) are the RNA (ribonucleic acid) of the cell and are also responsible for protein production. Lysosomes (B) act as “scavenger” cells, removing debris from within the cellular body. The Golgi apparatus (D) is involved in merocrine secretion. The endoplasmic reticulum (E) manufactures various products for use within and outside cells.

Question 85

84. Enamel is formed by ameloblasts, which are derived from the ectoderm. The ectoderm also signals the mesoderm to start the development of dentin and pulp. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 85

ANS: A Both statements are true (A). Enamel develops from the enamel organ, which is derived from the ectoderm. The enamel organ will differentiate into the inner enamel epithelium, the stellate reticulum, the stratum intermedium, and the outer enamel epithelium. The inner enamel epithelium will give rise to ameloblasts. The ectoderm’s production of ameloblasts is the signal to the mesodermal structure of the dental papilla to start the formation of dentin and pulp. Choices B, C, and D do not correctly reflect the statements.

Question 86

86. During facial development, the two structures forming the major facial structures are the frontonasal process and the pharyngeal (branchial) arch I. This process begins during week 6 in utero. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 86

ANS: C The correct choice is C. The first statement is true. The frontonasal process will form the forehead and the middle third of the face, including the nose, the philtrum, maxillary incisors, and the premaxillary area or the primary palate. The first pharyngeal (branchial) arch I forms the mandibular and maxillary processes, which will form the mandible, most of the maxillae, and palatine bones. The zygomatic bones of the cheek are also formed from these processes. The second statement is false. This process begins during week 3 in embryologic development. By week 6, the major facial structures have formed and are developing in complexity. Choices A, B, and D do not accurately reflect the statements

Question 87

87. Each is a paranasal sinus EXCEPT one. Which one is the EXCEPTION? A. Frontal B. Mandibular C. Maxillary D. Sphenoidal E. Ethmoidal

Answer 87

ANS: B There is no structure called the mandibular sinus (B). Paranasal sinuses include the frontal (A), maxillary (C), sphenoidal (D), and ethmoidal (E) sinuses.

Question 88

88. Which muscle involved in facial expression does not have a bony attachment, shapes and controls the size of the mouth opening, and helps create lip positions and movements during speech? A. Risorius B. Zygomaticus major C. Orbicularis oris D. Levator anguli oris

Answer 88

ANS: C The orbicularis oris muscle (C) shapes and controls the size of the mouth opening and is important in the creation of lip positions and movements during speech. The risorius muscle (A) stretches the lips laterally, retracting the labial commissure and widening the mouth to produce a grimace. The zygomaticus major muscle (B) elevates the labial commissure of the upper lip and pulls it laterally, thus helping create to a smile. The levator anguli oris muscle (D) elevates the labial commissure, as when a person smiles

Question 89

92. Which developmental disturbance appears as a “tooth within a tooth” on radiologic examination? A. Fusion B. Tubercles C. Gemination D. Dens in dente

Answer 89

ANS: D The abnormal invagination of the enamel organ into the dental papilla results in the developmental disturbance known as dens in dente (D) and appears as a “tooth within a tooth” on radiographic examination. In gemination (C), the single tooth germ tries unsuccessfully to divide into two tooth germs, resulting in a large single-rooted tooth with a common pulp cavity. With fusion (A), two adjacent tooth germs join together, leading to a large, falsely macrodontic tooth that can be verified with radiographic examination. Tubercles (B) are extra cusps that appear as small, round enamel extensions.

Question 90

89. Each is an anterior branch of the external carotid artery EXCEPT one. Which one is the EXCEPTION? A. Occipital B. Superior thyroid C. Facial D. LinguaL

Answer 90

ANS: A The occipital artery (A) is a posterior branch of the external carotid artery. The external carotid artery has four sets of branches, grouped according to location in relation to the main artery: (1) anterior, (2) medial, (3) posterior, and (4) terminal. The superior thyroid (B), facial (C), and lingual (D) arteries are all anterior branches of the external carotid artery.

Question 91

90. Which gland is associated with dry eye syndrome, (DES), also known as keratoconjunctivitis sicca? (KCS)? A. Thyroid B. Thymus C. Lacrimal D. Parathyroid

Answer 91

ANS: C Lacrimal glands (C) are paired exocrine glands that secrete lacrimal fluid, or tears. With dry eye syndrome, the lacrimal glands produce less fluid, a condition often associated with aging or certain medications. The thyroid (A), thymus (B), and parathyroid (D) glands are all endocrine glands, not exocrine glands. The thyroid gland (A) is the largest endocrine gland and secretes thyroxine directly into the vascular system to stimulate the body’s metabolic rate. The thymus gland (B) is part of the immune system and helps fight disease processes. The parathyroid gland (D) secretes parathyroid hormone directly into the vascular system to regulate phosphorus and calcium levels.

Question 92

91. The face and its related tissues begin to form during week 6 of prenatal development, within the fetal period. Facial development is completed by week 12. A. Both statements are true. B. Both statements are false. C. The first statement is true and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 92

ANS: D The correct choice is D. The first statement is false. The face and its related tissues begin to form at the beginning of week 4 in the embryonic period, not during week 6 in the fetal period. However, the second statement is true. Facial development starts during weeks 3 and 4 and is completed in the twelfth week. Choices A, B, and C do not correctly reflect the statements.

Question 93

93. Each is a type of connective tissue EXCEPT one. Which one is the EXCEPTION? A. Bone B. Blood C. Muscle D. Cartilage

Answer 93

ANS: C Muscle tissue (C) is part of the muscular system and is a classification of basic tissue in the same way that connective tissue is also a classification of basic body tissue. Bone (A) is a rigid type of specialized connective tissue that makes up the majority of the body’s mature skeleton. Blood (B) is a fluid specialized connective tissue that transports nutrients throughout the body. Cartilage (D) is a type of firm, noncalcified, specialized connective tissue that forms much of the temporary skeleton of the embryo and structurally supports certain soft tissues after birth

Question 94

94. Enamel may be lost through attrition, abrasion, erosion, caries, or abfraction. Radiographically, enamel appears more radiolucent than dentin or pulp, both of which appear more radiopaque. A. Both statements are true. B. Both statements are false. C. The first statement is true, and the second statement is false. D. The first statement is false, and the second statement is true.

Answer 94

ANS: C Choice C is correct. The first statement is true. Enamel may be lost through attrition (wearing away from tooth-to-tooth contact), abrasion (loss through friction from toothbrushing or toothpaste), erosion (loss through chemical means that do not involve bacteria), caries (loss through chemical means from cariogenic bacteria), or abfraction (loss through tensile and compressive forces during tooth flexure). However, the second statement is false. On radiographs, enamel appears more radiopaque (lighter) than dentin or pulp, both of which appear more radiolucent (darker). Choices A, B, and D do not accurately reflect the statements.

Question 95

95. Which acronym defines the correct sequence of words used to describe a tooth? A. D-T-A-Q B. D-A-C-T C. C-A-D-Q D. D-A-Q-T

Answer 95

ANS: D The correct sequence of words used to describe a tooth is based on the D-A-Q-T system (D), with D for dentition, A for arch, Q for quadrant, and T for tooth type. For example, a dental professional may refer to a permanent (D) mandibular (A) left (Q) premolar (T). Acronyms in choices A, B, and C are incorrectly sequenced.

Question 96

96. How many permanent anterior teeth are present in an adult mouth? A. 6 B. 8 C. 10 D. 12

Answer 96

ANS: D An adult mouth has 12 total permanent anterior teeth (D): 8 incisors (4 each lateral and central incisors [two in each arch]) and 4 canines (two in each arch). Figures in choices A, B, and C are less than 12 (the normal number of permanent anterior teeth).

Question 97

97. Which tooth numbers represent maxillary first premolars? A. #5 and #12 B. #4 and #13 C. #21 and #28 D. #24 and #25

Answer 97

ANS: A Teeth #5 and #12 (A) are maxillary first premolars. Teeth #4 and #13 (B) are maxillary second premolars. Teeth #21 and #28 (C) are mandibular first premolars. Teeth #24 and #25 (D) are mandibular central incisors

Question 98

98. Which statement is correct? (Select all that apply.) A. Maxillary second premolars are bifurcated with a buccal and palatal root. B. Mandibular molars are bifurcated with a mesial and distal root. C. Maxillary molars are trifurcated with a mesiobuccal, distobuccal, and palatal root. D. Maxillary first premolars are bifurcated with a buccal and palatal root.

Answer 98

ANS: B, C, D The correct choices are B, C, and D. Mandibular molars have a bifurcated root: mesial and distal (B). Maxillary molars have trifurcated roots: mesiobuccal, distobuccal, and palatal (C). Maxillary first premolars may have a bifurcated root: buccal and palatal (D). Maxillary second premolars are rarely bifurcated (A).