Teeth Whitening Knowledge 3 — Questions and Answers
Question 1: Tetracycline staining is classified as which type of tooth discoloration?
- Extrinsic
- Intrinsic (Correct answer)
- Surface
- Dietary
Correct answer: Intrinsic
Tetracycline staining is intrinsic because the antibiotic becomes incorporated into the dentin structure during tooth development.
Question 2: What whitening side effect is most commonly reported by patients?
- Permanent gum recession
- Increased tooth sensitivity (Correct answer)
- Enamel fractures
- Taste disturbances
Correct answer: Increased tooth sensitivity
Tooth sensitivity during or after whitening is the most frequently reported side effect, typically resolving within 24–48 hours.
Question 3: Which ingredient in whitening toothpaste primarily removes surface stains through physical abrasion rather than chemical bleaching?
- Hydrogen peroxide
- Sodium hexametaphosphate
- Silica or hydrated silica (Correct answer)
- Potassium nitrate
Correct answer: Silica or hydrated silica
Silica particles act as mild abrasives that physically polish away surface stains without chemically bleaching the tooth.
Question 4: What does the term 'vital bleaching' refer to in dentistry?
- Bleaching teeth with very high-concentration peroxide only
- Whitening living teeth that have intact pulps (Correct answer)
- Emergency whitening performed after trauma
- Bleaching under general anesthesia
Correct answer: Whitening living teeth that have intact pulps
Vital bleaching applies to whitening procedures performed on teeth that still have a living pulp, distinguishing them from non-vital (devitalized) teeth.
Question 5: Non-vital bleaching (internal bleaching) is most commonly performed on which type of tooth?
- Teeth with deep enamel cracks
- Endodontically treated (root canal) teeth (Correct answer)
- Teeth with severe fluorosis
- Impacted wisdom teeth
Correct answer: Endodontically treated (root canal) teeth
Internal bleaching is used on root-canal-treated teeth where the pulp chamber can be accessed and packed with a whitening agent.
Question 6: How does potassium nitrate function in whitening products marketed as 'sensitive' formulas?
- It increases the peroxide concentration
- It blocks dentinal tubules to reduce nerve stimulation (Correct answer)
- It hardens enamel to prevent peroxide penetration
- It neutralizes acidic peroxide byproducts
Correct answer: It blocks dentinal tubules to reduce nerve stimulation
Potassium nitrate calms nerve endings inside the tooth by depolarizing them, which reduces the perception of sensitivity.
Question 7: What is the primary reason whitening gels are more effective when delivered in custom-fitted trays compared to one-size strips?
- Trays contain higher peroxide concentrations
- Trays prevent saliva dilution and ensure uniform gel contact (Correct answer)
- Trays can be heated to activate the gel faster
- Trays block UV light from deactivating the peroxide
Correct answer: Trays prevent saliva dilution and ensure uniform gel contact
Custom trays create a sealed reservoir that prevents saliva from diluting the gel and ensures even coverage across all tooth surfaces.
Teeth Whitening Knowledge 3
Tetracycline staining is classified as which type of tooth discoloration?