The Definitive NDEB Written
Examination Prep Practice Questions
with Clinical Rationales
HEAD AND NECK ANATOMY
Question: The parotid gland is innervated by which cranial nerve for
secretomotor function?
Answer: Cranial Nerve IX (Glossopharyngeal)
Rationale: The parotid gland receives parasympathetic secretomotor
innervation from the glossopharyngeal nerve (CN IX) via the otic ganglion.
The facial nerve (CN VII) innervates the submandibular and sublingual
glands, not the parotid.
Question: Which foramen transmits the maxillary division of the trigeminal
nerve (V2)?
Answer: Foramen rotundum
Rationale: The foramen rotundum transmits the maxillary nerve (V2). The
foramen ovale transmits the mandibular nerve (V3), and the foramen
spinosum transmits the middle meningeal artery.
,Question: The infraorbital nerve is a branch of which nerve?
Answer: Maxillary nerve (V2)
Rationale: The infraorbital nerve is a terminal branch of the maxillary nerve
(V2), exiting through the infraorbital foramen to provide sensation to the
lower eyelid, nose, and upper lip.
Question: Which muscle is the primary protractor of the mandible?
Answer: Lateral pterygoid
Rationale: The lateral pterygoid attaches to the condyle and disc; bilateral
contraction protrudes the mandible. The masseter and temporalis are
elevators, and the medial pterygoid assists with elevation and lateral
movements.
Question: The parotid duct (Stensen's duct) opens into the oral cavity
opposite which tooth?
Answer: Maxillary second molar
Rationale: Stensen's duct opens on the buccal mucosa near the maxillary
second molar. This anatomical landmark is important for identifying the
parotid papilla.
,Question: Which nerve provides sensory innervation to the maxillary
posterior teeth?
Answer: Posterior superior alveolar nerve
Rationale: The posterior superior alveolar nerve is a branch of the maxillary
division of the trigeminal nerve (V2) and provides sensation to the maxillary
molars and associated buccal gingiva.
Question: The maxillary first molar has how many roots?
Answer: Three
Rationale: Maxillary first molars typically have three roots: mesiobuccal,
distobuccal, and palatal. The palatal root is usually the longest.
Question: Which tooth in the permanent dentition most commonly
exhibits a C-shaped root canal morphology?
Answer: Mandibular second molar
Rationale: C-shaped root canals are most frequently found in mandibular
second molars, particularly in certain ethnic populations. This anatomical
variation presents challenges during endodontic treatment.
, Question: The cementoenamel junction (CEJ) of a tooth typically overlaps
the cementum over enamel in what percentage of cases?
Answer: 60%
Rationale: The CEJ has three possible relationships: cementum overlapping
enamel in approximately 60% of cases, edge-to-edge in about 30%, and a
gap with exposed dentin in about 10%.
Question: Which papilla on the tongue is responsible for the majority of
taste sensation?
Answer: Fungiform papillae
Rationale: Fungiform papillae contain taste buds on their superior surface.
Filiform papillae are mechanical and do not contain taste buds.
Circumvallate and foliate papillae also contain taste buds but in smaller
numbers.
Question: Which cranial nerve provides motor innervation to the muscles
of mastication?
Answer: Trigeminal nerve – mandibular division (CN V3)
Rationale: The mandibular division of the trigeminal nerve (CN V3)
provides motor innervation to the muscles of mastication, including the
masseter, temporalis, and medial and lateral pterygoids. The facial nerve
(CN VII) innervates the muscles of facial expression.
Examination Prep Practice Questions
with Clinical Rationales
HEAD AND NECK ANATOMY
Question: The parotid gland is innervated by which cranial nerve for
secretomotor function?
Answer: Cranial Nerve IX (Glossopharyngeal)
Rationale: The parotid gland receives parasympathetic secretomotor
innervation from the glossopharyngeal nerve (CN IX) via the otic ganglion.
The facial nerve (CN VII) innervates the submandibular and sublingual
glands, not the parotid.
Question: Which foramen transmits the maxillary division of the trigeminal
nerve (V2)?
Answer: Foramen rotundum
Rationale: The foramen rotundum transmits the maxillary nerve (V2). The
foramen ovale transmits the mandibular nerve (V3), and the foramen
spinosum transmits the middle meningeal artery.
,Question: The infraorbital nerve is a branch of which nerve?
Answer: Maxillary nerve (V2)
Rationale: The infraorbital nerve is a terminal branch of the maxillary nerve
(V2), exiting through the infraorbital foramen to provide sensation to the
lower eyelid, nose, and upper lip.
Question: Which muscle is the primary protractor of the mandible?
Answer: Lateral pterygoid
Rationale: The lateral pterygoid attaches to the condyle and disc; bilateral
contraction protrudes the mandible. The masseter and temporalis are
elevators, and the medial pterygoid assists with elevation and lateral
movements.
Question: The parotid duct (Stensen's duct) opens into the oral cavity
opposite which tooth?
Answer: Maxillary second molar
Rationale: Stensen's duct opens on the buccal mucosa near the maxillary
second molar. This anatomical landmark is important for identifying the
parotid papilla.
,Question: Which nerve provides sensory innervation to the maxillary
posterior teeth?
Answer: Posterior superior alveolar nerve
Rationale: The posterior superior alveolar nerve is a branch of the maxillary
division of the trigeminal nerve (V2) and provides sensation to the maxillary
molars and associated buccal gingiva.
Question: The maxillary first molar has how many roots?
Answer: Three
Rationale: Maxillary first molars typically have three roots: mesiobuccal,
distobuccal, and palatal. The palatal root is usually the longest.
Question: Which tooth in the permanent dentition most commonly
exhibits a C-shaped root canal morphology?
Answer: Mandibular second molar
Rationale: C-shaped root canals are most frequently found in mandibular
second molars, particularly in certain ethnic populations. This anatomical
variation presents challenges during endodontic treatment.
, Question: The cementoenamel junction (CEJ) of a tooth typically overlaps
the cementum over enamel in what percentage of cases?
Answer: 60%
Rationale: The CEJ has three possible relationships: cementum overlapping
enamel in approximately 60% of cases, edge-to-edge in about 30%, and a
gap with exposed dentin in about 10%.
Question: Which papilla on the tongue is responsible for the majority of
taste sensation?
Answer: Fungiform papillae
Rationale: Fungiform papillae contain taste buds on their superior surface.
Filiform papillae are mechanical and do not contain taste buds.
Circumvallate and foliate papillae also contain taste buds but in smaller
numbers.
Question: Which cranial nerve provides motor innervation to the muscles
of mastication?
Answer: Trigeminal nerve – mandibular division (CN V3)
Rationale: The mandibular division of the trigeminal nerve (CN V3)
provides motor innervation to the muscles of mastication, including the
masseter, temporalis, and medial and lateral pterygoids. The facial nerve
(CN VII) innervates the muscles of facial expression.
