NBDHE PRACTICE EXAM 2025/2026 | HIGH-YIELD
QUESTIONS, CORRECT ANSWERS & DETAILED
RATIONALES (PASS ON YOUR FIRST ATTEMPT!)
Stop stressing over the NBDHE! This premium study bank delivers 220+ highly curated,
realistic practice questions built exactly to the 2025/2026 exam blueprint. Every item
features bolded correct answers and comprehensive, concept-clearing Rationales across
pharmacology, anatomy, and oral pathology. Perfect for quick active-recall sessions or mock
test simulation. Lock in your scaled score of 75+ and transition from dental hygiene student
to registered RDH with complete confidence!
,1. Which of the following cells are the first to arrive at an acute site of inflammation?
• A. Macrophages
• B. Neutrophils
• C. Plasma cells
• D. Mast cells
Rationale: Neutrophils (polymorphonuclear leukocytes) are the primary responders in
acute inflammation, arriving within hours. Macrophages arrive later during chronic
stages.
2. Which cranial nerve is responsible for the sensory innervation of the anterior two-thirds
of the tongue?
• A. VII (Facial)
• B. IX (Glossopharyngeal)
• C. V (Trigeminal - Lingual nerve)
• D. XII (Hypoglossal)
Rationale: General sensation to the anterior 2/3 of the tongue is provided by the
lingual nerve, a branch of CN V3. Taste for this area is CN VII, while CN XII handles
motor function.
3. A patient taking an ACE inhibitor like lisinopril is most likely to experience which oral side
effect?
• A. Gingival hyperplasia
• B. Xerostomia
• C. Aphthous ulcers
• D. Petechiae
Rationale: Xerostomia is a common side effect of many antihypertensive medications,
including ACE inhibitors. Gingival hyperplasia is linked to calcium channel blockers like
nifedipine.
4. Which of the following instruments is best suited for removing light calculus from the
interproximal surfaces of mandibular anterior teeth?
• A. Gracey 13/14
,• B. Sickle scaler (e.g., H6/H7)
• C. Gracey 11/12
• D. Universal curette (e.g., Columbia 13/14)
Rationale: Sickle scalers with thin blades are highly effective for interproximal
supragingival calculus removal on narrow anterior teeth. Gracey 13/14 is designed for
posterior distal surfaces.
5. What is the active ingredient in professional in-office vital tooth bleaching gels?
• A. Hydrogen peroxide
• B. Carbamide peroxide
• C. Sodium perborate
• D. Potassium nitrate
Rationale: In-office bleaching systems typically use high concentrations of hydrogen
peroxide (30-35%). Carbamide peroxide is more common in take-home whitening kits.
6. Which type of cyst forms around the crown of an unerupted or developing tooth?
• A. Radicular cyst
• B. Primordial cyst
• C. Dentigerous cyst
• D. Residual cyst
Rationale: A dentigerous (follicular) cyst forms around the crown of an unerupted
tooth, most commonly mandibular third molars. Radicular cysts form at the apex of
necrotic teeth.
7. An optimal concentration of fluoride in community drinking water is:
• A. 0.5 ppm
• B. 0.7 ppm
• C. 1.0 ppm
• D. 1.2 ppm
Rationale: The U.S. Department of Health and Human Services recommends an
optimal fluoride level of 0.7 milligrams per litre (ppm) to prevent dental caries while
minimizing fluorosis.
, 8. Which vitamin deficiency is directly associated with angular cheilitis and glossitis?
• A. Vitamin A
• B. Vitamin B2 (Riboflavin)
• C. Vitamin C
• D. Vitamin K
Rationale: B-complex vitamin deficiencies, particularly B2 (riboflavin) and B12,
manifest orally as angular cheilitis, glossitis, and mucosal pallor. Vitamin C deficiency
causes scurvy.
9. During periodontal probing, the distance from the cementoenamel junction (CEJ) to the
base of the sulcus is known as the:
• A. Probing depth
• B. Clinical attachment level
• C. Gingival margin position
• D. Biological width
Rationale: Clinical attachment level (CAL) measures the total distance from a fixed
point (the CEJ) to the bottom of the periodontal pocket.
10. Which bacteria are heavily implicated in the initiation of dental caries?
• A. Streptococcus mutans
• B. Lactobacillus acidophilus
• C. Actinomyces viscosus
• D. Porphyromonas gingivalis
Rationale: Streptococcus mutans is the primary bacteria responsible for initiating
enamel caries due to its acidogenic properties. Lactobacillus is active in progressive,
deeper lesions.
11. What error causes a panoramic radiograph to display a "reverse smile line" (frown)?
• A. Patient's chin is tipped too high
• B. Patient's chin is tipped too low
• C. Patient is positioned too far forward
QUESTIONS, CORRECT ANSWERS & DETAILED
RATIONALES (PASS ON YOUR FIRST ATTEMPT!)
Stop stressing over the NBDHE! This premium study bank delivers 220+ highly curated,
realistic practice questions built exactly to the 2025/2026 exam blueprint. Every item
features bolded correct answers and comprehensive, concept-clearing Rationales across
pharmacology, anatomy, and oral pathology. Perfect for quick active-recall sessions or mock
test simulation. Lock in your scaled score of 75+ and transition from dental hygiene student
to registered RDH with complete confidence!
,1. Which of the following cells are the first to arrive at an acute site of inflammation?
• A. Macrophages
• B. Neutrophils
• C. Plasma cells
• D. Mast cells
Rationale: Neutrophils (polymorphonuclear leukocytes) are the primary responders in
acute inflammation, arriving within hours. Macrophages arrive later during chronic
stages.
2. Which cranial nerve is responsible for the sensory innervation of the anterior two-thirds
of the tongue?
• A. VII (Facial)
• B. IX (Glossopharyngeal)
• C. V (Trigeminal - Lingual nerve)
• D. XII (Hypoglossal)
Rationale: General sensation to the anterior 2/3 of the tongue is provided by the
lingual nerve, a branch of CN V3. Taste for this area is CN VII, while CN XII handles
motor function.
3. A patient taking an ACE inhibitor like lisinopril is most likely to experience which oral side
effect?
• A. Gingival hyperplasia
• B. Xerostomia
• C. Aphthous ulcers
• D. Petechiae
Rationale: Xerostomia is a common side effect of many antihypertensive medications,
including ACE inhibitors. Gingival hyperplasia is linked to calcium channel blockers like
nifedipine.
4. Which of the following instruments is best suited for removing light calculus from the
interproximal surfaces of mandibular anterior teeth?
• A. Gracey 13/14
,• B. Sickle scaler (e.g., H6/H7)
• C. Gracey 11/12
• D. Universal curette (e.g., Columbia 13/14)
Rationale: Sickle scalers with thin blades are highly effective for interproximal
supragingival calculus removal on narrow anterior teeth. Gracey 13/14 is designed for
posterior distal surfaces.
5. What is the active ingredient in professional in-office vital tooth bleaching gels?
• A. Hydrogen peroxide
• B. Carbamide peroxide
• C. Sodium perborate
• D. Potassium nitrate
Rationale: In-office bleaching systems typically use high concentrations of hydrogen
peroxide (30-35%). Carbamide peroxide is more common in take-home whitening kits.
6. Which type of cyst forms around the crown of an unerupted or developing tooth?
• A. Radicular cyst
• B. Primordial cyst
• C. Dentigerous cyst
• D. Residual cyst
Rationale: A dentigerous (follicular) cyst forms around the crown of an unerupted
tooth, most commonly mandibular third molars. Radicular cysts form at the apex of
necrotic teeth.
7. An optimal concentration of fluoride in community drinking water is:
• A. 0.5 ppm
• B. 0.7 ppm
• C. 1.0 ppm
• D. 1.2 ppm
Rationale: The U.S. Department of Health and Human Services recommends an
optimal fluoride level of 0.7 milligrams per litre (ppm) to prevent dental caries while
minimizing fluorosis.
, 8. Which vitamin deficiency is directly associated with angular cheilitis and glossitis?
• A. Vitamin A
• B. Vitamin B2 (Riboflavin)
• C. Vitamin C
• D. Vitamin K
Rationale: B-complex vitamin deficiencies, particularly B2 (riboflavin) and B12,
manifest orally as angular cheilitis, glossitis, and mucosal pallor. Vitamin C deficiency
causes scurvy.
9. During periodontal probing, the distance from the cementoenamel junction (CEJ) to the
base of the sulcus is known as the:
• A. Probing depth
• B. Clinical attachment level
• C. Gingival margin position
• D. Biological width
Rationale: Clinical attachment level (CAL) measures the total distance from a fixed
point (the CEJ) to the bottom of the periodontal pocket.
10. Which bacteria are heavily implicated in the initiation of dental caries?
• A. Streptococcus mutans
• B. Lactobacillus acidophilus
• C. Actinomyces viscosus
• D. Porphyromonas gingivalis
Rationale: Streptococcus mutans is the primary bacteria responsible for initiating
enamel caries due to its acidogenic properties. Lactobacillus is active in progressive,
deeper lesions.
11. What error causes a panoramic radiograph to display a "reverse smile line" (frown)?
• A. Patient's chin is tipped too high
• B. Patient's chin is tipped too low
• C. Patient is positioned too far forward
