NATIONAL BOARD DENTAL HYGIENE
EXAMINATION PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A | INSTANT DOWNLOAD PDF
Q1. Which tissue primarily supports the tooth in the alveolar socket?
A. Enamel
B. Cementum
C. Periodontal ligament
D. Dentin
Correct Answer: C. Periodontal ligament
Rationale: The periodontal ligament is a specialized connective tissue that
attaches the tooth to the alveolar bone. It absorbs mechanical stress during
chewing and maintains tooth stability.
Q2. Which instrument is best for removing heavy supragingival calculus?
A. Explorer
B. Curette
C. Sickle scaler
D. Periodontal probe
Correct Answer: C. Sickle scaler
Rationale: Sickle scalers are designed with a pointed tip and triangular cross-
section, making them ideal for removing heavy supragingival calculus, especially
on anterior teeth and interproximal surfaces.
,Q3. What is the primary function of fluoride in dental health?
A. Strengthen pulp tissue
B. Increase saliva production
C. Enhance enamel resistance to acid
D. Prevent tooth eruption
Correct Answer: C. Enhance enamel resistance to acid
Rationale: Fluoride strengthens enamel by forming fluorapatite, which is more
resistant to acid attacks from bacteria, reducing caries risk.
Q4. Which condition is characterized by inflammation of the gingiva without
bone loss?
A. Periodontitis
B. Gingivitis
C. Periapical abscess
D. Oral candidiasis
Correct Answer: B. Gingivitis
Rationale: Gingivitis is the earliest stage of periodontal disease, involving gum
inflammation without attachment or bone loss and is reversible with proper
care.
Q5. What is the primary cause of dental caries?
A. Viral infection
B. Bacterial acid production
C. Trauma
D. Genetic mutation
Correct Answer: B. Bacterial acid production
Rationale: Streptococcus mutans metabolizes sugars and produces acids that
demineralize enamel, leading to caries formation.
,Q6. Which nerve provides sensation to the maxillary teeth?
A. Mandibular nerve
B. Facial nerve
C. Maxillary nerve
D. Hypoglossal nerve
Correct Answer: C. Maxillary nerve
Rationale: The maxillary branch of the trigeminal nerve (CN V2) supplies sensory
innervation to the maxillary teeth and related structures.
Q7. Which oral condition is commonly associated with HIV infection?
A. Leukoplakia
B. Oral candidiasis
C. Dental fluorosis
D. Hypercementosis
Correct Answer: B. Oral candidiasis
Rationale: Immunosuppression in HIV patients increases susceptibility to
opportunistic infections like Candida albicans, causing oral thrush.
Q8. What is the main purpose of scaling and root planing?
A. Whitening teeth
B. Removing plaque and calculus below gingiva
C. Polishing enamel
D. Restoring missing teeth
Correct Answer: B. Removing plaque and calculus below gingiva
Rationale: Scaling and root planing removes bacterial deposits from root
surfaces and smooths them to promote periodontal healing.
Q9. Which vitamin deficiency is linked to delayed wound healing in the oral
cavity?
A. Vitamin A
, B. Vitamin C
C. Vitamin D
D. Vitamin K
Correct Answer: B. Vitamin C
Rationale: Vitamin C is essential for collagen synthesis; deficiency leads to
impaired healing and bleeding gums (scurvy).
Q10. Which tooth surface is most prone to caries in molars?
A. Lingual
B. Occlusal
C. Buccal
D. Cervical
Correct Answer: B. Occlusal
Rationale: Occlusal surfaces contain pits and fissures that trap food and
bacteria, making them highly susceptible to caries.
Q11. What is the normal pH of saliva?
A. 4.0–5.0
B. 5.0–6.0
C. 6.2–7.6
D. 8.0–9.0
Correct Answer: C. 6.2–7.6
Rationale: Saliva is slightly acidic to neutral, which helps maintain oral
homeostasis and neutralize acids from bacterial activity.
Q12. Which dental material is commonly used for temporary restorations?
A. Amalgam
B. Composite resin
C. Zinc oxide eugenol
D. Gold alloy
EXAMINATION PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A | INSTANT DOWNLOAD PDF
Q1. Which tissue primarily supports the tooth in the alveolar socket?
A. Enamel
B. Cementum
C. Periodontal ligament
D. Dentin
Correct Answer: C. Periodontal ligament
Rationale: The periodontal ligament is a specialized connective tissue that
attaches the tooth to the alveolar bone. It absorbs mechanical stress during
chewing and maintains tooth stability.
Q2. Which instrument is best for removing heavy supragingival calculus?
A. Explorer
B. Curette
C. Sickle scaler
D. Periodontal probe
Correct Answer: C. Sickle scaler
Rationale: Sickle scalers are designed with a pointed tip and triangular cross-
section, making them ideal for removing heavy supragingival calculus, especially
on anterior teeth and interproximal surfaces.
,Q3. What is the primary function of fluoride in dental health?
A. Strengthen pulp tissue
B. Increase saliva production
C. Enhance enamel resistance to acid
D. Prevent tooth eruption
Correct Answer: C. Enhance enamel resistance to acid
Rationale: Fluoride strengthens enamel by forming fluorapatite, which is more
resistant to acid attacks from bacteria, reducing caries risk.
Q4. Which condition is characterized by inflammation of the gingiva without
bone loss?
A. Periodontitis
B. Gingivitis
C. Periapical abscess
D. Oral candidiasis
Correct Answer: B. Gingivitis
Rationale: Gingivitis is the earliest stage of periodontal disease, involving gum
inflammation without attachment or bone loss and is reversible with proper
care.
Q5. What is the primary cause of dental caries?
A. Viral infection
B. Bacterial acid production
C. Trauma
D. Genetic mutation
Correct Answer: B. Bacterial acid production
Rationale: Streptococcus mutans metabolizes sugars and produces acids that
demineralize enamel, leading to caries formation.
,Q6. Which nerve provides sensation to the maxillary teeth?
A. Mandibular nerve
B. Facial nerve
C. Maxillary nerve
D. Hypoglossal nerve
Correct Answer: C. Maxillary nerve
Rationale: The maxillary branch of the trigeminal nerve (CN V2) supplies sensory
innervation to the maxillary teeth and related structures.
Q7. Which oral condition is commonly associated with HIV infection?
A. Leukoplakia
B. Oral candidiasis
C. Dental fluorosis
D. Hypercementosis
Correct Answer: B. Oral candidiasis
Rationale: Immunosuppression in HIV patients increases susceptibility to
opportunistic infections like Candida albicans, causing oral thrush.
Q8. What is the main purpose of scaling and root planing?
A. Whitening teeth
B. Removing plaque and calculus below gingiva
C. Polishing enamel
D. Restoring missing teeth
Correct Answer: B. Removing plaque and calculus below gingiva
Rationale: Scaling and root planing removes bacterial deposits from root
surfaces and smooths them to promote periodontal healing.
Q9. Which vitamin deficiency is linked to delayed wound healing in the oral
cavity?
A. Vitamin A
, B. Vitamin C
C. Vitamin D
D. Vitamin K
Correct Answer: B. Vitamin C
Rationale: Vitamin C is essential for collagen synthesis; deficiency leads to
impaired healing and bleeding gums (scurvy).
Q10. Which tooth surface is most prone to caries in molars?
A. Lingual
B. Occlusal
C. Buccal
D. Cervical
Correct Answer: B. Occlusal
Rationale: Occlusal surfaces contain pits and fissures that trap food and
bacteria, making them highly susceptible to caries.
Q11. What is the normal pH of saliva?
A. 4.0–5.0
B. 5.0–6.0
C. 6.2–7.6
D. 8.0–9.0
Correct Answer: C. 6.2–7.6
Rationale: Saliva is slightly acidic to neutral, which helps maintain oral
homeostasis and neutralize acids from bacterial activity.
Q12. Which dental material is commonly used for temporary restorations?
A. Amalgam
B. Composite resin
C. Zinc oxide eugenol
D. Gold alloy
