National Board Dental Hygiene
Examination Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. Which structure primarily supports the tooth in the alveolar bone?
A. Gingiva
B. Periodontal ligament
C. Enamel
D. Pulp
Correct Answer: B. Periodontal ligament
Rationale: The periodontal ligament is a specialized connective tissue that
anchors the cementum of the tooth to the alveolar bone. It absorbs
occlusal forces and provides sensory feedback, making it essential for
tooth stability and proprioception.
2. The hardest substance in the human body is:
A. Dentin
B. Cementum
C. Enamel
D. Bone
Correct Answer: C. Enamel
Rationale: Enamel is composed mainly of hydroxyapatite crystals and is
the most mineralized and hardest tissue in the human body. It protects the
underlying dentin and pulp from mechanical and chemical damage.
3. What is the primary cause of dental caries?
A. Viral infection
, B. Fungal infection
C. Acid-producing bacteria
D. Mechanical abrasion
Correct Answer: C. Acid-producing bacteria
Rationale: Dental caries is primarily caused by acidogenic bacteria such as
Streptococcus mutans, which metabolize sugars and produce acids that
demineralize enamel.
4. Which vitamin is essential for calcium absorption and bone health?
A. Vitamin A
B. Vitamin D
C. Vitamin C
D. Vitamin K
Correct Answer: B. Vitamin D
Rationale: Vitamin D regulates calcium and phosphate absorption in the
intestines, which is essential for maintaining bone density and proper
tooth mineralization.
5. Gingivitis is best described as:
A. Irreversible bone loss
B. Inflammation of the gingiva without bone loss
C. Tooth decay
D. Periodontal ligament destruction
Correct Answer: B. Inflammation of the gingiva without bone loss
Rationale: Gingivitis is the earliest stage of periodontal disease
characterized by gingival inflammation without attachment or bone loss,
and it is reversible with proper oral hygiene.
6. The primary function of saliva includes:
A. Digestion only
B. Lubrication and antimicrobial activity
C. Tooth formation
D. Enamel hardening
Correct Answer: B. Lubrication and antimicrobial activity
, Rationale: Saliva moistens oral tissues, aids in digestion, buffers acids, and
contains antimicrobial agents like lysozyme and IgA that protect against
infection.
7. Which tooth surface faces the tongue?
A. Buccal
B. Labial
C. Lingual
D. Occlusal
Correct Answer: C. Lingual
Rationale: The lingual surface of teeth refers to the side facing the tongue,
particularly in mandibular and maxillary anterior teeth.
8. The main mineral component of enamel is:
A. Calcium carbonate
B. Hydroxyapatite
C. Fluoride
D. Collagen
Correct Answer: B. Hydroxyapatite
Rationale: Enamel is primarily composed of hydroxyapatite crystals, a
calcium phosphate compound that gives enamel its hardness and
resistance to wear.
9. Which nerve provides sensation to the maxillary teeth?
A. Mandibular nerve
B. Facial nerve
C. Maxillary nerve
D. Glossopharyngeal nerve
Correct Answer: C. Maxillary nerve
Rationale: The maxillary division of the trigeminal nerve (V2) provides
sensory innervation to the maxillary teeth and associated structures.
10.Dental plaque is best described as:
A. Hardened calculus
B. Soft bacterial biofilm
Examination Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. Which structure primarily supports the tooth in the alveolar bone?
A. Gingiva
B. Periodontal ligament
C. Enamel
D. Pulp
Correct Answer: B. Periodontal ligament
Rationale: The periodontal ligament is a specialized connective tissue that
anchors the cementum of the tooth to the alveolar bone. It absorbs
occlusal forces and provides sensory feedback, making it essential for
tooth stability and proprioception.
2. The hardest substance in the human body is:
A. Dentin
B. Cementum
C. Enamel
D. Bone
Correct Answer: C. Enamel
Rationale: Enamel is composed mainly of hydroxyapatite crystals and is
the most mineralized and hardest tissue in the human body. It protects the
underlying dentin and pulp from mechanical and chemical damage.
3. What is the primary cause of dental caries?
A. Viral infection
, B. Fungal infection
C. Acid-producing bacteria
D. Mechanical abrasion
Correct Answer: C. Acid-producing bacteria
Rationale: Dental caries is primarily caused by acidogenic bacteria such as
Streptococcus mutans, which metabolize sugars and produce acids that
demineralize enamel.
4. Which vitamin is essential for calcium absorption and bone health?
A. Vitamin A
B. Vitamin D
C. Vitamin C
D. Vitamin K
Correct Answer: B. Vitamin D
Rationale: Vitamin D regulates calcium and phosphate absorption in the
intestines, which is essential for maintaining bone density and proper
tooth mineralization.
5. Gingivitis is best described as:
A. Irreversible bone loss
B. Inflammation of the gingiva without bone loss
C. Tooth decay
D. Periodontal ligament destruction
Correct Answer: B. Inflammation of the gingiva without bone loss
Rationale: Gingivitis is the earliest stage of periodontal disease
characterized by gingival inflammation without attachment or bone loss,
and it is reversible with proper oral hygiene.
6. The primary function of saliva includes:
A. Digestion only
B. Lubrication and antimicrobial activity
C. Tooth formation
D. Enamel hardening
Correct Answer: B. Lubrication and antimicrobial activity
, Rationale: Saliva moistens oral tissues, aids in digestion, buffers acids, and
contains antimicrobial agents like lysozyme and IgA that protect against
infection.
7. Which tooth surface faces the tongue?
A. Buccal
B. Labial
C. Lingual
D. Occlusal
Correct Answer: C. Lingual
Rationale: The lingual surface of teeth refers to the side facing the tongue,
particularly in mandibular and maxillary anterior teeth.
8. The main mineral component of enamel is:
A. Calcium carbonate
B. Hydroxyapatite
C. Fluoride
D. Collagen
Correct Answer: B. Hydroxyapatite
Rationale: Enamel is primarily composed of hydroxyapatite crystals, a
calcium phosphate compound that gives enamel its hardness and
resistance to wear.
9. Which nerve provides sensation to the maxillary teeth?
A. Mandibular nerve
B. Facial nerve
C. Maxillary nerve
D. Glossopharyngeal nerve
Correct Answer: C. Maxillary nerve
Rationale: The maxillary division of the trigeminal nerve (V2) provides
sensory innervation to the maxillary teeth and associated structures.
10.Dental plaque is best described as:
A. Hardened calculus
B. Soft bacterial biofilm
