PREVENTIVE DENTISTRY EXAM 1 | DENTAL
HYGIENIST| LATEST 2025-2026 QUESTION AND
CORRECT ANSWER WITH EXPLANATION
WEST COAST UNIVERSITY
1. A 10-year-old patient presents with early enamel demineralization on
the maxillary incisors. Which preventive intervention is MOST
appropriate at this stage?
A. Immediate composite restoration
B. Application of topical fluoride varnish
C. Extraction of affected teeth
D. Placement of full coverage crowns
Correct Answer: B
Rationale: Early enamel demineralization is reversible. Fluoride varnish
enhances remineralization and inhibits progression, making it the most
appropriate non-invasive intervention.
2. A patient reports frequent snacking on fermentable carbohydrates
throughout the day. What is the PRIMARY mechanism increasing their
caries risk?
A. Increased salivary buffering capacity
B. Reduced oral bacterial load
C. Prolonged acidic oral environment
D. Enhanced enamel remineralization
Correct Answer: C
Rationale: Frequent carbohydrate intake leads to repeated acid
production by bacteria, maintaining a low pH environment that promotes
enamel demineralization.
3. Which index is MOST commonly used by dental hygienists to assess
plaque accumulation?
A. DMFT Index
B. Gingival Index
,C. Plaque Index (Silness and Löe)
D. CPI (Community Periodontal Index)
Correct Answer: C
Rationale: The Plaque Index (Silness and Löe) specifically measures the
thickness of plaque at the gingival margin, making it ideal for plaque
assessment.
4. A patient with xerostomia is at increased risk for dental caries
primarily due to:
A. Increased enamel thickness
B. Reduced salivary flow and buffering action
C. Higher calcium concentration in saliva
D. Decreased bacterial activity
Correct Answer: B
Rationale: Saliva plays a key role in buffering acids and remineralization.
Reduced flow increases susceptibility to caries.
5. Which fluoride concentration is typically found in professional fluoride
varnish?
A. 1,000 ppm
B. 2,500 ppm
C. 5,000 ppm
D. 22,600 ppm
Correct Answer: D
Rationale: Fluoride varnish commonly contains 5% sodium fluoride,
equivalent to approximately 22,600 ppm fluoride.
6. During oral hygiene instruction, which brushing technique is MOST
effective for gingival margin cleaning?
A. Fones technique
B. Bass technique
, C. Stillman technique
D. Charter’s technique
Correct Answer: B
Rationale: The Bass technique allows bristles to reach the gingival sulcus,
effectively removing plaque at the gumline.
7. A patient presents with white spot lesions after orthodontic treatment.
What is the BEST preventive recommendation?
A. Immediate bleaching treatment
B. Increased sugar intake for remineralization
C. Topical fluoride and improved oral hygiene
D. Extraction of affected teeth
Correct Answer: C
Rationale: White spot lesions are early caries lesions that can be
remineralized with fluoride and proper plaque control.
8. Which dietary component has the GREATEST cariogenic potential?
A. Proteins
B. Fats
C. Fermentable carbohydrates
D. Fiber
Correct Answer: C
Rationale: Fermentable carbohydrates are metabolized by oral bacteria
to produce acids that demineralize enamel.
9. A dental hygienist is assessing periodontal health. Which sign indicates
early gingivitis?
A. Attachment loss
B. Bone resorption
C. Bleeding on probing
D. Tooth mobility
HYGIENIST| LATEST 2025-2026 QUESTION AND
CORRECT ANSWER WITH EXPLANATION
WEST COAST UNIVERSITY
1. A 10-year-old patient presents with early enamel demineralization on
the maxillary incisors. Which preventive intervention is MOST
appropriate at this stage?
A. Immediate composite restoration
B. Application of topical fluoride varnish
C. Extraction of affected teeth
D. Placement of full coverage crowns
Correct Answer: B
Rationale: Early enamel demineralization is reversible. Fluoride varnish
enhances remineralization and inhibits progression, making it the most
appropriate non-invasive intervention.
2. A patient reports frequent snacking on fermentable carbohydrates
throughout the day. What is the PRIMARY mechanism increasing their
caries risk?
A. Increased salivary buffering capacity
B. Reduced oral bacterial load
C. Prolonged acidic oral environment
D. Enhanced enamel remineralization
Correct Answer: C
Rationale: Frequent carbohydrate intake leads to repeated acid
production by bacteria, maintaining a low pH environment that promotes
enamel demineralization.
3. Which index is MOST commonly used by dental hygienists to assess
plaque accumulation?
A. DMFT Index
B. Gingival Index
,C. Plaque Index (Silness and Löe)
D. CPI (Community Periodontal Index)
Correct Answer: C
Rationale: The Plaque Index (Silness and Löe) specifically measures the
thickness of plaque at the gingival margin, making it ideal for plaque
assessment.
4. A patient with xerostomia is at increased risk for dental caries
primarily due to:
A. Increased enamel thickness
B. Reduced salivary flow and buffering action
C. Higher calcium concentration in saliva
D. Decreased bacterial activity
Correct Answer: B
Rationale: Saliva plays a key role in buffering acids and remineralization.
Reduced flow increases susceptibility to caries.
5. Which fluoride concentration is typically found in professional fluoride
varnish?
A. 1,000 ppm
B. 2,500 ppm
C. 5,000 ppm
D. 22,600 ppm
Correct Answer: D
Rationale: Fluoride varnish commonly contains 5% sodium fluoride,
equivalent to approximately 22,600 ppm fluoride.
6. During oral hygiene instruction, which brushing technique is MOST
effective for gingival margin cleaning?
A. Fones technique
B. Bass technique
, C. Stillman technique
D. Charter’s technique
Correct Answer: B
Rationale: The Bass technique allows bristles to reach the gingival sulcus,
effectively removing plaque at the gumline.
7. A patient presents with white spot lesions after orthodontic treatment.
What is the BEST preventive recommendation?
A. Immediate bleaching treatment
B. Increased sugar intake for remineralization
C. Topical fluoride and improved oral hygiene
D. Extraction of affected teeth
Correct Answer: C
Rationale: White spot lesions are early caries lesions that can be
remineralized with fluoride and proper plaque control.
8. Which dietary component has the GREATEST cariogenic potential?
A. Proteins
B. Fats
C. Fermentable carbohydrates
D. Fiber
Correct Answer: C
Rationale: Fermentable carbohydrates are metabolized by oral bacteria
to produce acids that demineralize enamel.
9. A dental hygienist is assessing periodontal health. Which sign indicates
early gingivitis?
A. Attachment loss
B. Bone resorption
C. Bleeding on probing
D. Tooth mobility
