Teeth Whitening Teeth Whitening 4 — Questions and Answers
Question 1: What is the approximate pH of most professional hydrogen peroxide whitening gels?
- pH 9–11 (alkaline) (Correct answer)
- pH 7 (neutral)
- pH 5–6 (mildly acidic)
- pH 3–4 (strongly acidic)
Correct answer: pH 9–11 (alkaline)
Most professional whitening gels are formulated at an alkaline pH (9–11) to keep the peroxide stable and reduce enamel erosion risk.
Question 2: Which tissue is protected by a light-cured resin barrier or rubber dam during in-office whitening?
- Enamel
- Dentin
- Gingiva (gums) (Correct answer)
- Cementum
Correct answer: Gingiva (gums)
A gingival barrier or rubber dam is applied to protect the soft gum tissue from the high-concentration bleaching gel used during in-office procedures.
Question 3: A patient notices white spots on teeth after using whitening strips for 2 weeks. The MOST likely cause is:
- Enamel erosion from the acidic gel
- Temporary dehydration of the enamel surface (Correct answer)
- Fluorosis activated by peroxide
- Resin infiltration of subsurface lesions
Correct answer: Temporary dehydration of the enamel surface
White spots appearing immediately after whitening are usually caused by temporary enamel dehydration and typically resolve within a few hours as moisture returns.
Question 4: Which dietary habit would BEST help maintain whitening results long-term?
- Drinking staining beverages through a straw (Correct answer)
- Brushing with baking soda once a week
- Rinsing with mouthwash immediately after meals
- Using a whitening pen daily indefinitely
Correct answer: Drinking staining beverages through a straw
Using a straw keeps chromogen-rich beverages like coffee, tea, and soda from contacting the front tooth surfaces, helping to preserve whitening results.
Question 5: How does fluoride applied after whitening benefit the teeth?
- It enhances the whitening effect of peroxide
- It re-mineralizes enamel and reduces post-treatment sensitivity (Correct answer)
- It seals the tooth surface to prevent future stains permanently
- It neutralizes residual peroxide to stop the bleaching process
Correct answer: It re-mineralizes enamel and reduces post-treatment sensitivity
Fluoride helps re-mineralize the slightly porous enamel surface after bleaching and reduces sensitivity by reinforcing the tooth structure.
Question 6: What is the typical recommended waiting period before eating or drinking after an in-office whitening session?
- 10–15 minutes
- 30–60 minutes
- 2–4 hours (Correct answer)
- 24–48 hours
Correct answer: 2–4 hours
Most dentists advise waiting 2–4 hours after in-office whitening before consuming food or drink to allow the enamel pores to close and reduce staining risk.
Question 7: Which at-home whitening system releases bleaching agent MOST slowly, reducing sensitivity?
- High-concentration whitening strips worn for 30 minutes
- 10% carbamide peroxide in a custom tray worn overnight (Correct answer)
- 35% hydrogen peroxide pen applied directly
- Whitening toothpaste used twice daily
Correct answer: 10% carbamide peroxide in a custom tray worn overnight
10% carbamide peroxide releases hydrogen peroxide gradually overnight, providing a gentler whitening action that typically causes less sensitivity than higher-concentration products.
Teeth Whitening Teeth Whitening 4
What is the approximate pH of most professional hydrogen peroxide whitening gels?