NBDHE National Board Dental Hygiene Examination 2026
Latest Comprehensive Study Guide with Practice Questions
Dental Hygiene Review, Verified Answers, Detailed
Rationales, Success Workbook
QUESTION 1
The dental pulp is primarily composed of which type of connective tissue?
A) Dense regular connective tissue
B) Loose areolar connective tissue
C) Specialized loose connective tissue
D) Adipose tissue
ANSWER: C) Specialized loose connective tissue
RATIONALE: The dental pulp is composed of specialized loose connective tissue
that contains nerves, blood vessels, lymphatics, fibroblasts, and odontoblasts. It is
unique in that it is enclosed within the rigid dentin walls of the pulp chamber.
Dense regular connective tissue (A) is found in tendons and ligaments. Loose
areolar connective tissue (B) is found throughout the body but lacks the specialized
cellular components of pulp. Adipose tissue (D) is fat tissue.
QUESTION 2
The neuromuscular junction is a synapse between a motor neuron and:
A) Another neuron
B) A gland cell
C) A muscle fiber
D) A sensory receptor
ANSWER: C) A muscle fiber
RATIONALE: The neuromuscular junction is the specialized synapse between a
motor neuron and a skeletal muscle fiber. When an action potential reaches the
axon terminal, acetylcholine is released, which binds to receptors on the muscle
fiber, leading to depolarization and muscle contraction. This is distinct from
synapses between neurons (A) or neuron-gland junctions (B).
,QUESTION 3
Which of the following organisms is the most common cause of infective
endocarditis following dental procedures?
A) Staphylococcus aureus
B) Viridans group streptococci
C) Pseudomonas aeruginosa
D) Candida albicans
ANSWER: B) Viridans group streptococci
RATIONALE: Viridans group streptococci (particularly S. mutans and S.
sanguinis) are the most common cause of infective endocarditis following dental
procedures. These organisms are normal flora of the oral cavity and can enter the
bloodstream during dental procedures, adhering to damaged heart
valves. Staphylococcus aureus (A) is more commonly associated with skin
infections. Pseudomonas aeruginosa (C) is associated with immunocompromised
patients. Candida albicans (D) is a fungal pathogen.
QUESTION 4
What is the primary mechanism of action of local anesthetics?
A) Blocking sodium channels in the neuronal membrane
B) Blocking calcium channels in the neuronal membrane
C) Blocking potassium channels in the neuronal membrane
D) Blocking neurotransmitter release from the presynaptic terminal
ANSWER: A) Blocking sodium channels in the neuronal membrane
RATIONALE: Local anesthetics (e.g., lidocaine, bupivacaine) work by reversibly
blocking voltage-gated sodium channels in the neuronal membrane. This prevents
the influx of sodium ions required for depolarization, thereby blocking the
generation and propagation of action potentials. Calcium channels (B) are blocked
by other drug classes. Potassium channels (C) are not the primary target.
Neurotransmitter release (D) is blocked by different mechanisms (e.g., botulinum
toxin).
,QUESTION 5
The cell type responsible for bone resorption is the:
A) Osteoblast
B) Osteocyte
C) Osteoclast
D) Chondrocyte
ANSWER: C) Osteoclast
RATIONALE: Osteoclasts are multinucleated cells responsible for bone
resorption (breakdown). They secrete acids and enzymes that dissolve bone
mineral and degrade the organic matrix. Osteoblasts (A) are responsible for bone
formation. Osteocytes (B) are mature bone cells that maintain bone tissue.
Chondrocytes (D) are cartilage cells.
QUESTION 6
The antibiotic of choice for prophylaxis against infective endocarditis in patients
allergic to penicillin is:
A) Amoxicillin
B) Cephalexin
C) Clindamycin
D) Tetracycline
ANSWER: C) Clindamycin
RATIONALE: For patients allergic to penicillin, the American Heart Association
recommends clindamycin (600 mg) as an alternative antibiotic for infective
endocarditis prophylaxis prior to dental procedures. Amoxicillin (A) is the first-
line choice for non-allergic patients but is contraindicated in penicillin-allergic
patients. Cephalexin (B) has cross-reactivity with penicillin in some patients.
Tetracycline (D) is not recommended for this indication.
QUESTION 7
Where is the parotid duct (Stensen's duct) located?
A) Floor of the mouth adjacent to the lingual frenum
B) Buccal mucosa adjacent to the maxillary first and second molars
, C) Floor of the mouth near the sublingual caruncle
D) Palatal mucosa near the midline
ANSWER: B) Buccal mucosa adjacent to the maxillary first and second
molars
RATIONALE: Stensen's duct (parotid duct) opens into the oral cavity through a
papilla on the buccal mucosa opposite the maxillary first and second molars.
Wharton's duct (submandibular duct) (C) opens at the sublingual caruncle on the
floor of the mouth. Bartholin's duct (sublingual duct) (A) opens near the lingual
frenum.
QUESTION 8
Which cranial nerve provides motor innervation to the muscles of mastication?
A) Cranial nerve V (Trigeminal)
B) Cranial nerve VII (Facial)
C) Cranial nerve IX (Glossopharyngeal)
D) Cranial nerve XII (Hypoglossal)
ANSWER: A) Cranial nerve V (Trigeminal)
RATIONALE: The mandibular branch (V3) of the trigeminal nerve (cranial nerve
V) provides motor innervation to the muscles of mastication (masseter, temporalis,
medial pterygoid, lateral pterygoid). Cranial nerve VII (B) innervates the muscles
of facial expression. Cranial nerve IX (C) innervates the stylopharyngeus muscle.
Cranial nerve XII (D) innervates the muscles of the tongue.
QUESTION 9
The "fight or flight" response is mediated primarily by the:
A) Parasympathetic nervous system
B) Sympathetic nervous system
C) Somatic nervous system
D) Enteric nervous system
ANSWER: B) Sympathetic nervous system
Latest Comprehensive Study Guide with Practice Questions
Dental Hygiene Review, Verified Answers, Detailed
Rationales, Success Workbook
QUESTION 1
The dental pulp is primarily composed of which type of connective tissue?
A) Dense regular connective tissue
B) Loose areolar connective tissue
C) Specialized loose connective tissue
D) Adipose tissue
ANSWER: C) Specialized loose connective tissue
RATIONALE: The dental pulp is composed of specialized loose connective tissue
that contains nerves, blood vessels, lymphatics, fibroblasts, and odontoblasts. It is
unique in that it is enclosed within the rigid dentin walls of the pulp chamber.
Dense regular connective tissue (A) is found in tendons and ligaments. Loose
areolar connective tissue (B) is found throughout the body but lacks the specialized
cellular components of pulp. Adipose tissue (D) is fat tissue.
QUESTION 2
The neuromuscular junction is a synapse between a motor neuron and:
A) Another neuron
B) A gland cell
C) A muscle fiber
D) A sensory receptor
ANSWER: C) A muscle fiber
RATIONALE: The neuromuscular junction is the specialized synapse between a
motor neuron and a skeletal muscle fiber. When an action potential reaches the
axon terminal, acetylcholine is released, which binds to receptors on the muscle
fiber, leading to depolarization and muscle contraction. This is distinct from
synapses between neurons (A) or neuron-gland junctions (B).
,QUESTION 3
Which of the following organisms is the most common cause of infective
endocarditis following dental procedures?
A) Staphylococcus aureus
B) Viridans group streptococci
C) Pseudomonas aeruginosa
D) Candida albicans
ANSWER: B) Viridans group streptococci
RATIONALE: Viridans group streptococci (particularly S. mutans and S.
sanguinis) are the most common cause of infective endocarditis following dental
procedures. These organisms are normal flora of the oral cavity and can enter the
bloodstream during dental procedures, adhering to damaged heart
valves. Staphylococcus aureus (A) is more commonly associated with skin
infections. Pseudomonas aeruginosa (C) is associated with immunocompromised
patients. Candida albicans (D) is a fungal pathogen.
QUESTION 4
What is the primary mechanism of action of local anesthetics?
A) Blocking sodium channels in the neuronal membrane
B) Blocking calcium channels in the neuronal membrane
C) Blocking potassium channels in the neuronal membrane
D) Blocking neurotransmitter release from the presynaptic terminal
ANSWER: A) Blocking sodium channels in the neuronal membrane
RATIONALE: Local anesthetics (e.g., lidocaine, bupivacaine) work by reversibly
blocking voltage-gated sodium channels in the neuronal membrane. This prevents
the influx of sodium ions required for depolarization, thereby blocking the
generation and propagation of action potentials. Calcium channels (B) are blocked
by other drug classes. Potassium channels (C) are not the primary target.
Neurotransmitter release (D) is blocked by different mechanisms (e.g., botulinum
toxin).
,QUESTION 5
The cell type responsible for bone resorption is the:
A) Osteoblast
B) Osteocyte
C) Osteoclast
D) Chondrocyte
ANSWER: C) Osteoclast
RATIONALE: Osteoclasts are multinucleated cells responsible for bone
resorption (breakdown). They secrete acids and enzymes that dissolve bone
mineral and degrade the organic matrix. Osteoblasts (A) are responsible for bone
formation. Osteocytes (B) are mature bone cells that maintain bone tissue.
Chondrocytes (D) are cartilage cells.
QUESTION 6
The antibiotic of choice for prophylaxis against infective endocarditis in patients
allergic to penicillin is:
A) Amoxicillin
B) Cephalexin
C) Clindamycin
D) Tetracycline
ANSWER: C) Clindamycin
RATIONALE: For patients allergic to penicillin, the American Heart Association
recommends clindamycin (600 mg) as an alternative antibiotic for infective
endocarditis prophylaxis prior to dental procedures. Amoxicillin (A) is the first-
line choice for non-allergic patients but is contraindicated in penicillin-allergic
patients. Cephalexin (B) has cross-reactivity with penicillin in some patients.
Tetracycline (D) is not recommended for this indication.
QUESTION 7
Where is the parotid duct (Stensen's duct) located?
A) Floor of the mouth adjacent to the lingual frenum
B) Buccal mucosa adjacent to the maxillary first and second molars
, C) Floor of the mouth near the sublingual caruncle
D) Palatal mucosa near the midline
ANSWER: B) Buccal mucosa adjacent to the maxillary first and second
molars
RATIONALE: Stensen's duct (parotid duct) opens into the oral cavity through a
papilla on the buccal mucosa opposite the maxillary first and second molars.
Wharton's duct (submandibular duct) (C) opens at the sublingual caruncle on the
floor of the mouth. Bartholin's duct (sublingual duct) (A) opens near the lingual
frenum.
QUESTION 8
Which cranial nerve provides motor innervation to the muscles of mastication?
A) Cranial nerve V (Trigeminal)
B) Cranial nerve VII (Facial)
C) Cranial nerve IX (Glossopharyngeal)
D) Cranial nerve XII (Hypoglossal)
ANSWER: A) Cranial nerve V (Trigeminal)
RATIONALE: The mandibular branch (V3) of the trigeminal nerve (cranial nerve
V) provides motor innervation to the muscles of mastication (masseter, temporalis,
medial pterygoid, lateral pterygoid). Cranial nerve VII (B) innervates the muscles
of facial expression. Cranial nerve IX (C) innervates the stylopharyngeus muscle.
Cranial nerve XII (D) innervates the muscles of the tongue.
QUESTION 9
The "fight or flight" response is mediated primarily by the:
A) Parasympathetic nervous system
B) Sympathetic nervous system
C) Somatic nervous system
D) Enteric nervous system
ANSWER: B) Sympathetic nervous system
