NATIONAL BOARD DENTAL HYGIENE
EXAMINATION (NBDHE) 2026 Latest Comprehensive
Study Guide with Practice Questions, Comprehensive Dental
Hygiene Board Review, Detailed Explanations, Verified
Answers, Complete Success Workbook
The three major content areas of Component A are:
1. Scientific Basis for Dental Hygiene Practice (~56 questions, 28%)
2. Provision of Clinical Dental Hygiene Services (~124 questions, 62%)
3. Community Health/Research Principles (~20 questions, 10%)
Key topics include anatomic sciences, physiology, pathology, pharmacology,
microbiology, immunology, biochemistry, nutrition, patient assessment,
radiographic interpretation, periodontal procedures, preventive agents, and
professional responsibility.
DOMAIN 1: SCIENTIFIC BASIS FOR DENTAL HYGIENE PRACTICE
(Questions 1-30)
This domain covers anatomic sciences, physiology, biochemistry and nutrition,
microbiology and immunology, general and oral pathology, and pharmacology.
Question 1
Which cranial nerve provides motor innervation to the muscles of mastication?
A) Trigeminal nerve (CN V)
B) Facial nerve (CN VII)
C) Glossopharyngeal nerve (CN IX)
D) Hypoglossal nerve (CN XII)
E) Accessory nerve (CN XI)
Correct Answer: A
,Rationale: The trigeminal nerve (CN V) provides motor innervation to the
muscles of mastication (masseter, temporalis, medial pterygoid, lateral pterygoid)
via the mandibular division (V₃). The facial nerve (B) innervates muscles of facial
expression. The glossopharyngeal nerve (C) innervates the stylopharyngeus
muscle. The hypoglossal nerve (D) innervates intrinsic and extrinsic tongue
muscles. The accessory nerve (E) innervates the sternocleidomastoid and trapezius
muscles.
Question 2
The permanent dentition consists of how many teeth in a normal adult?
A) 20
B) 24
C) 28
D) 32
E) 36
Correct Answer: D
Rationale: The normal permanent dentition consists of 32 teeth: 8 incisors, 4
canines, 8 premolars, and 12 molars (including 4 third molars). The primary
dentition (A) has 20 teeth. Options B, C, and E are incorrect.
Question 3
Which of the following cells is responsible for bone resorption?
A) Osteoblasts
B) Osteocytes
C) Osteoclasts
D) Chondrocytes
E) Fibroblasts
Correct Answer: C
,Rationale: Osteoclasts are multinucleated cells responsible for bone resorption
through the release of acids and enzymes. Osteoblasts (A) are responsible for bone
formation. Osteocytes (B) are mature bone cells that maintain bone matrix.
Chondrocytes (D) are cartilage cells. Fibroblasts (E) produce collagen and
extracellular matrix.
Question 4
What is the primary neurotransmitter released at the neuromuscular junction?
A) Dopamine
B) Norepinephrine
C) Acetylcholine
D) Serotonin
E) GABA
Correct Answer: C
Rationale: Acetylcholine is the primary neurotransmitter released at the
neuromuscular junction, stimulating muscle contraction. Dopamine (A) and
norepinephrine (B) are catecholamines involved in the central and sympathetic
nervous systems. Serotonin (D) is involved in mood regulation. GABA (E) is the
primary inhibitory neurotransmitter in the CNS.
Question 5
Which vitamin is essential for the synthesis of clotting factors in the liver?
A) Vitamin A
B) Vitamin B₁₂
C) Vitamin C
D) Vitamin D
E) Vitamin K
Correct Answer: E
, Rationale: Vitamin K is essential for the synthesis of clotting factors II, VII, IX,
and X in the liver. Vitamin A (A) is important for vision and epithelial health.
Vitamin B₁₂ (B) is important for red blood cell formation and neurological
function. Vitamin C (C) is important for collagen synthesis and immune function.
Vitamin D (D) is important for calcium absorption and bone health.
Question 6
The most common site for oral squamous cell carcinoma is the:
A) Buccal mucosa
B) Floor of the mouth
C) Hard palate
D) Tongue (lateral border)
E) Gingiva
Correct Answer: D
Rationale: The lateral border of the tongue is the most common site for oral
squamous cell carcinoma, followed by the floor of the mouth. The buccal mucosa
(A) and gingiva (E) are less common sites. The hard palate (C) is a relatively
uncommon site for squamous cell carcinoma.
Question 7
Which immunoglobulin is primarily found in saliva and provides mucosal
immunity?
A) IgG
B) IgM
C) IgA
D) IgE
E) IgD
Correct Answer: C
EXAMINATION (NBDHE) 2026 Latest Comprehensive
Study Guide with Practice Questions, Comprehensive Dental
Hygiene Board Review, Detailed Explanations, Verified
Answers, Complete Success Workbook
The three major content areas of Component A are:
1. Scientific Basis for Dental Hygiene Practice (~56 questions, 28%)
2. Provision of Clinical Dental Hygiene Services (~124 questions, 62%)
3. Community Health/Research Principles (~20 questions, 10%)
Key topics include anatomic sciences, physiology, pathology, pharmacology,
microbiology, immunology, biochemistry, nutrition, patient assessment,
radiographic interpretation, periodontal procedures, preventive agents, and
professional responsibility.
DOMAIN 1: SCIENTIFIC BASIS FOR DENTAL HYGIENE PRACTICE
(Questions 1-30)
This domain covers anatomic sciences, physiology, biochemistry and nutrition,
microbiology and immunology, general and oral pathology, and pharmacology.
Question 1
Which cranial nerve provides motor innervation to the muscles of mastication?
A) Trigeminal nerve (CN V)
B) Facial nerve (CN VII)
C) Glossopharyngeal nerve (CN IX)
D) Hypoglossal nerve (CN XII)
E) Accessory nerve (CN XI)
Correct Answer: A
,Rationale: The trigeminal nerve (CN V) provides motor innervation to the
muscles of mastication (masseter, temporalis, medial pterygoid, lateral pterygoid)
via the mandibular division (V₃). The facial nerve (B) innervates muscles of facial
expression. The glossopharyngeal nerve (C) innervates the stylopharyngeus
muscle. The hypoglossal nerve (D) innervates intrinsic and extrinsic tongue
muscles. The accessory nerve (E) innervates the sternocleidomastoid and trapezius
muscles.
Question 2
The permanent dentition consists of how many teeth in a normal adult?
A) 20
B) 24
C) 28
D) 32
E) 36
Correct Answer: D
Rationale: The normal permanent dentition consists of 32 teeth: 8 incisors, 4
canines, 8 premolars, and 12 molars (including 4 third molars). The primary
dentition (A) has 20 teeth. Options B, C, and E are incorrect.
Question 3
Which of the following cells is responsible for bone resorption?
A) Osteoblasts
B) Osteocytes
C) Osteoclasts
D) Chondrocytes
E) Fibroblasts
Correct Answer: C
,Rationale: Osteoclasts are multinucleated cells responsible for bone resorption
through the release of acids and enzymes. Osteoblasts (A) are responsible for bone
formation. Osteocytes (B) are mature bone cells that maintain bone matrix.
Chondrocytes (D) are cartilage cells. Fibroblasts (E) produce collagen and
extracellular matrix.
Question 4
What is the primary neurotransmitter released at the neuromuscular junction?
A) Dopamine
B) Norepinephrine
C) Acetylcholine
D) Serotonin
E) GABA
Correct Answer: C
Rationale: Acetylcholine is the primary neurotransmitter released at the
neuromuscular junction, stimulating muscle contraction. Dopamine (A) and
norepinephrine (B) are catecholamines involved in the central and sympathetic
nervous systems. Serotonin (D) is involved in mood regulation. GABA (E) is the
primary inhibitory neurotransmitter in the CNS.
Question 5
Which vitamin is essential for the synthesis of clotting factors in the liver?
A) Vitamin A
B) Vitamin B₁₂
C) Vitamin C
D) Vitamin D
E) Vitamin K
Correct Answer: E
, Rationale: Vitamin K is essential for the synthesis of clotting factors II, VII, IX,
and X in the liver. Vitamin A (A) is important for vision and epithelial health.
Vitamin B₁₂ (B) is important for red blood cell formation and neurological
function. Vitamin C (C) is important for collagen synthesis and immune function.
Vitamin D (D) is important for calcium absorption and bone health.
Question 6
The most common site for oral squamous cell carcinoma is the:
A) Buccal mucosa
B) Floor of the mouth
C) Hard palate
D) Tongue (lateral border)
E) Gingiva
Correct Answer: D
Rationale: The lateral border of the tongue is the most common site for oral
squamous cell carcinoma, followed by the floor of the mouth. The buccal mucosa
(A) and gingiva (E) are less common sites. The hard palate (C) is a relatively
uncommon site for squamous cell carcinoma.
Question 7
Which immunoglobulin is primarily found in saliva and provides mucosal
immunity?
A) IgG
B) IgM
C) IgA
D) IgE
E) IgD
Correct Answer: C
