HESI DENTAL HYGIENE EXAM | QUESTIONS AND
ANSWERS | VERIFIED ANSWERS PLUS RATIONALES | EXAM
ALREADY GRADED A+ | LATEST EXAM
1. What is the primary purpose of fluoride in dentistry?
A. Whitening teeth
B. Strengthening enamel
C. Removing plaque
D. Treating gum disease
Answer: B. Strengthening enamel
Rationale: Fluoride helps remineralize enamel and prevent dental caries by making teeth more
resistant to acid attacks.
2. Which instrument is used to measure periodontal pocket depth?
A. Explorer
B. Probe
C. Scaler
D. Curette
Answer: B. Probe
Rationale: A periodontal probe is calibrated in millimeters to measure the depth of gingival sulci
and periodontal pockets.
3. What is the recommended interval for professional dental cleanings for most patients?
A. Every month
B. Every 3–6 months
C. Every year
D. Every 2 years
Answer: B. Every 3–6 months
Rationale: Most patients benefit from dental prophylaxis every 3–6 months to maintain oral
health and prevent periodontal disease.
4. Which bacteria is most commonly associated with dental caries?
A. Porphyromonas gingivalis
B. Streptococcus mutans
C. Lactobacillus acidophilus
D. Actinomyces israelii
Answer: B. Streptococcus mutans
Rationale: Streptococcus mutans metabolizes sugars into acids that demineralize enamel,
leading to cavities.
,5. What type of radiograph is best for detecting interproximal caries?
A. Panoramic
B. Bitewing
C. Periapical
D. Occlusal
Answer: B. Bitewing
Rationale: Bitewing radiographs provide detailed images of the crowns of posterior teeth,
making them ideal for detecting interproximal decay.
6. Which of the following is the most effective method for removing supragingival plaque?
A. Flossing
B. Brushing with a soft-bristled toothbrush
C. Using a water flosser
D. Mouth rinses
Answer: B. Brushing with a soft-bristled toothbrush
Rationale: Brushing mechanically removes plaque from tooth surfaces, which is the most
effective way to reduce bacterial accumulation.
7. What is the purpose of scaling and root planing?
A. Remove dental caries
B. Treat gingivitis and periodontitis
C. Apply sealants
D. Reduce tooth sensitivity
Answer: B. Treat gingivitis and periodontitis
Rationale: Scaling removes calculus and plaque, while root planing smooths root surfaces to
reduce bacterial colonization.
8. Which cranial nerve is responsible for sensation in the face?
A. Facial (VII)
B. Trigeminal (V)
C. Glossopharyngeal (IX)
D. Vagus (X)
Answer: B. Trigeminal (V)
Rationale: The trigeminal nerve provides sensory innervation to the face, including the oral
cavity.
9. What is the main ingredient in most dental sealants?
A. Glass ionomer
B. Composite resin
C. Amalgam
D. Zinc oxide
,Answer: B. Composite resin
Rationale: Dental sealants are usually made of resin-based materials that flow into pits and
fissures to prevent decay.
10. Which condition is characterized by inflammation of the gums without loss of bone?
A. Gingivitis
B. Periodontitis
C. Dental caries
D. Abrasion
Answer: A. Gingivitis
Rationale: Gingivitis involves inflammation of the gingiva but does not cause bone loss, which
differentiates it from periodontitis.
11. What is the recommended fluoride concentration in toothpaste for adults?
A. 500 ppm
B. 1000–1500 ppm
C. 2500 ppm
D. 5000 ppm
Answer: B. 1000–1500 ppm
Rationale: Most adult toothpastes contain 1000–1500 ppm fluoride to prevent cavities safely.
12. Which dental procedure removes infected pulp tissue?
A. Extraction
B. Root canal therapy
C. Crown placement
D. Scaling
Answer: B. Root canal therapy
Rationale: Root canal therapy removes infected pulp from the tooth canal and seals it to prevent
further infection.
13. What is the most common site for oral cancer?
A. Tongue
B. Hard palate
C. Buccal mucosa
D. Gingiva
Answer: A. Tongue
Rationale: The lateral borders of the tongue are the most frequent site of oral cancer,
emphasizing the need for oral exams.
14. Which vitamin deficiency is associated with scurvy?
A. Vitamin A
B. Vitamin C
, C. Vitamin D
D. Vitamin K
Answer: B. Vitamin C
Rationale: Vitamin C deficiency leads to scurvy, causing bleeding gums, poor wound healing,
and weakened connective tissue.
15. How often should dental floss be used?
A. Once a week
B. Daily
C. Twice a month
D. Only when food is stuck
Answer: B. Daily
Rationale: Daily flossing removes plaque and food particles between teeth where brushes cannot
reach.
16. Which condition is caused by acid erosion of tooth enamel?
A. Abrasion
B. Erosion
C. Attrition
D. Caries
Answer: B. Erosion
Rationale: Acid erosion results from exposure to acidic foods or gastric acid, leading to loss of
enamel.
17. What is the most appropriate personal protective equipment (PPE) when performing
ultrasonic scaling?
A. Gloves and mask only
B. Gloves, mask, eyewear, and gown
C. Mask and eyewear only
D. Gloves only
Answer: B. Gloves, mask, eyewear, and gown
Rationale: Ultrasonic scaling generates aerosols, requiring full PPE to protect against pathogen
exposure.
18. What is the purpose of a dental dam?
A. Reduce tooth sensitivity
B. Isolate teeth during procedures
C. Whitening teeth
D. Measure periodontal pockets
ANSWERS | VERIFIED ANSWERS PLUS RATIONALES | EXAM
ALREADY GRADED A+ | LATEST EXAM
1. What is the primary purpose of fluoride in dentistry?
A. Whitening teeth
B. Strengthening enamel
C. Removing plaque
D. Treating gum disease
Answer: B. Strengthening enamel
Rationale: Fluoride helps remineralize enamel and prevent dental caries by making teeth more
resistant to acid attacks.
2. Which instrument is used to measure periodontal pocket depth?
A. Explorer
B. Probe
C. Scaler
D. Curette
Answer: B. Probe
Rationale: A periodontal probe is calibrated in millimeters to measure the depth of gingival sulci
and periodontal pockets.
3. What is the recommended interval for professional dental cleanings for most patients?
A. Every month
B. Every 3–6 months
C. Every year
D. Every 2 years
Answer: B. Every 3–6 months
Rationale: Most patients benefit from dental prophylaxis every 3–6 months to maintain oral
health and prevent periodontal disease.
4. Which bacteria is most commonly associated with dental caries?
A. Porphyromonas gingivalis
B. Streptococcus mutans
C. Lactobacillus acidophilus
D. Actinomyces israelii
Answer: B. Streptococcus mutans
Rationale: Streptococcus mutans metabolizes sugars into acids that demineralize enamel,
leading to cavities.
,5. What type of radiograph is best for detecting interproximal caries?
A. Panoramic
B. Bitewing
C. Periapical
D. Occlusal
Answer: B. Bitewing
Rationale: Bitewing radiographs provide detailed images of the crowns of posterior teeth,
making them ideal for detecting interproximal decay.
6. Which of the following is the most effective method for removing supragingival plaque?
A. Flossing
B. Brushing with a soft-bristled toothbrush
C. Using a water flosser
D. Mouth rinses
Answer: B. Brushing with a soft-bristled toothbrush
Rationale: Brushing mechanically removes plaque from tooth surfaces, which is the most
effective way to reduce bacterial accumulation.
7. What is the purpose of scaling and root planing?
A. Remove dental caries
B. Treat gingivitis and periodontitis
C. Apply sealants
D. Reduce tooth sensitivity
Answer: B. Treat gingivitis and periodontitis
Rationale: Scaling removes calculus and plaque, while root planing smooths root surfaces to
reduce bacterial colonization.
8. Which cranial nerve is responsible for sensation in the face?
A. Facial (VII)
B. Trigeminal (V)
C. Glossopharyngeal (IX)
D. Vagus (X)
Answer: B. Trigeminal (V)
Rationale: The trigeminal nerve provides sensory innervation to the face, including the oral
cavity.
9. What is the main ingredient in most dental sealants?
A. Glass ionomer
B. Composite resin
C. Amalgam
D. Zinc oxide
,Answer: B. Composite resin
Rationale: Dental sealants are usually made of resin-based materials that flow into pits and
fissures to prevent decay.
10. Which condition is characterized by inflammation of the gums without loss of bone?
A. Gingivitis
B. Periodontitis
C. Dental caries
D. Abrasion
Answer: A. Gingivitis
Rationale: Gingivitis involves inflammation of the gingiva but does not cause bone loss, which
differentiates it from periodontitis.
11. What is the recommended fluoride concentration in toothpaste for adults?
A. 500 ppm
B. 1000–1500 ppm
C. 2500 ppm
D. 5000 ppm
Answer: B. 1000–1500 ppm
Rationale: Most adult toothpastes contain 1000–1500 ppm fluoride to prevent cavities safely.
12. Which dental procedure removes infected pulp tissue?
A. Extraction
B. Root canal therapy
C. Crown placement
D. Scaling
Answer: B. Root canal therapy
Rationale: Root canal therapy removes infected pulp from the tooth canal and seals it to prevent
further infection.
13. What is the most common site for oral cancer?
A. Tongue
B. Hard palate
C. Buccal mucosa
D. Gingiva
Answer: A. Tongue
Rationale: The lateral borders of the tongue are the most frequent site of oral cancer,
emphasizing the need for oral exams.
14. Which vitamin deficiency is associated with scurvy?
A. Vitamin A
B. Vitamin C
, C. Vitamin D
D. Vitamin K
Answer: B. Vitamin C
Rationale: Vitamin C deficiency leads to scurvy, causing bleeding gums, poor wound healing,
and weakened connective tissue.
15. How often should dental floss be used?
A. Once a week
B. Daily
C. Twice a month
D. Only when food is stuck
Answer: B. Daily
Rationale: Daily flossing removes plaque and food particles between teeth where brushes cannot
reach.
16. Which condition is caused by acid erosion of tooth enamel?
A. Abrasion
B. Erosion
C. Attrition
D. Caries
Answer: B. Erosion
Rationale: Acid erosion results from exposure to acidic foods or gastric acid, leading to loss of
enamel.
17. What is the most appropriate personal protective equipment (PPE) when performing
ultrasonic scaling?
A. Gloves and mask only
B. Gloves, mask, eyewear, and gown
C. Mask and eyewear only
D. Gloves only
Answer: B. Gloves, mask, eyewear, and gown
Rationale: Ultrasonic scaling generates aerosols, requiring full PPE to protect against pathogen
exposure.
18. What is the purpose of a dental dam?
A. Reduce tooth sensitivity
B. Isolate teeth during procedures
C. Whitening teeth
D. Measure periodontal pockets
