DENTAL MATERIALS EXAM 5 | DENTAL
HYGIENIST| DENTAL HYGIENIST | LATEST
2025-2026 QUESTION AND CORRECT ANSWER
WITH EXPLANATION WEST COAST
UNIVERSITY
1. Question
A patient presents with near-total failure of composite restorations within
6 months across multiple quadrants. What is the MOST likely primary
cause?
A. Excess fluoride exposure
B. High caries activity with biofilm imbalance and poor dietary control
C. Over-polishing of restorations
D. Low occlusal force environment
Correct Answer: B
Rationale: Widespread early failure strongly indicates uncontrolled
cariogenic environment.
2. Question
Which step in adhesive dentistry is MOST sensitive to technique errors?
A. Enamel etching
B. Dentin bonding and hybrid layer formation
C. Occlusal adjustment
D. Radiographic evaluation
Correct Answer: B
Rationale: Dentin bonding is highly technique-sensitive and moisture
dependent.
3. Question
What is the PRIMARY purpose of the hybrid layer?
,A. Increase fluoride release
B. Create resin–collagen micromechanical interlocking zone
C. Reduce plaque accumulation
D. Strengthen enamel crystals
Correct Answer: B
Rationale: Hybrid layer is the foundation of adhesive bonding strength.
4. Question
A composite restoration fails due to marginal gaps shortly after placement.
What is the MOST likely cause?
A. Excess fluoride
B. Polymerization shrinkage stress exceeding bond strength
C. High enamel mineralization
D. Increased saliva buffering
Correct Answer: B
Rationale: Shrinkage pulls composite away from cavity walls.
5. Question
Which property is MOST important for resisting mastication forces?
A. Color stability
B. Compressive strength
C. Taste
D. Solubility
Correct Answer: B
Rationale: Compressive strength determines load-bearing capacity.
6. Question
What is the MAIN disadvantage of composite restorations in posterior
teeth?
, A. High strength
B. Polymerization shrinkage and fatigue failure
C. High radiopacity
D. Good esthetics
Correct Answer: B
Rationale: Shrinkage and cyclic loading cause long-term failure.
7. Question
Which material is MOST susceptible to galvanic corrosion?
A. Ceramic
B. Dissimilar metal restorations in saliva
C. Composite resin
D. Acrylic resin
Correct Answer: B
Rationale: Electrochemical reactions occur between different metals.
8. Question
What is the MAIN role of bonding primers?
A. Increase enamel hardness
B. Enhance resin penetration into dentin
C. Remove caries
D. Increase fluoride release
Correct Answer: B
Rationale: Primers improve wetting and infiltration.
9. Question
Which failure mode is MOST typical for ceramics?
A. Plastic deformation
B. Brittle fracture due to crack propagation
HYGIENIST| DENTAL HYGIENIST | LATEST
2025-2026 QUESTION AND CORRECT ANSWER
WITH EXPLANATION WEST COAST
UNIVERSITY
1. Question
A patient presents with near-total failure of composite restorations within
6 months across multiple quadrants. What is the MOST likely primary
cause?
A. Excess fluoride exposure
B. High caries activity with biofilm imbalance and poor dietary control
C. Over-polishing of restorations
D. Low occlusal force environment
Correct Answer: B
Rationale: Widespread early failure strongly indicates uncontrolled
cariogenic environment.
2. Question
Which step in adhesive dentistry is MOST sensitive to technique errors?
A. Enamel etching
B. Dentin bonding and hybrid layer formation
C. Occlusal adjustment
D. Radiographic evaluation
Correct Answer: B
Rationale: Dentin bonding is highly technique-sensitive and moisture
dependent.
3. Question
What is the PRIMARY purpose of the hybrid layer?
,A. Increase fluoride release
B. Create resin–collagen micromechanical interlocking zone
C. Reduce plaque accumulation
D. Strengthen enamel crystals
Correct Answer: B
Rationale: Hybrid layer is the foundation of adhesive bonding strength.
4. Question
A composite restoration fails due to marginal gaps shortly after placement.
What is the MOST likely cause?
A. Excess fluoride
B. Polymerization shrinkage stress exceeding bond strength
C. High enamel mineralization
D. Increased saliva buffering
Correct Answer: B
Rationale: Shrinkage pulls composite away from cavity walls.
5. Question
Which property is MOST important for resisting mastication forces?
A. Color stability
B. Compressive strength
C. Taste
D. Solubility
Correct Answer: B
Rationale: Compressive strength determines load-bearing capacity.
6. Question
What is the MAIN disadvantage of composite restorations in posterior
teeth?
, A. High strength
B. Polymerization shrinkage and fatigue failure
C. High radiopacity
D. Good esthetics
Correct Answer: B
Rationale: Shrinkage and cyclic loading cause long-term failure.
7. Question
Which material is MOST susceptible to galvanic corrosion?
A. Ceramic
B. Dissimilar metal restorations in saliva
C. Composite resin
D. Acrylic resin
Correct Answer: B
Rationale: Electrochemical reactions occur between different metals.
8. Question
What is the MAIN role of bonding primers?
A. Increase enamel hardness
B. Enhance resin penetration into dentin
C. Remove caries
D. Increase fluoride release
Correct Answer: B
Rationale: Primers improve wetting and infiltration.
9. Question
Which failure mode is MOST typical for ceramics?
A. Plastic deformation
B. Brittle fracture due to crack propagation
