Question

Which of the following is effective in restoring enamel bond strength of composite resin post-bleaching?

• A. Sodium ascorbate
• B. Citric acid
• C. EDTA
• D. Sodium bicarbonate

Hint:

After bleaching, wait for 1–2 weeks or apply sodium ascorbate to immediately restore composite bond strength.

Answer 1

The Correct Option is A

Step 1: Effect of Bleaching on Bond Strength.
After tooth bleaching, residual oxygen and free radicals remain within enamelThese residual oxidizing agents interfere with resin polymerizationAs a result, the bond strength of composite resin to enamel is significantly reduced immediately after bleaching
Step 2: Mechanism to Restore Bond Strength.
To neutralize the residual oxygen, an antioxidant is requiredSodium ascorbate is a potent antioxidantIt neutralizes free radicals and restores the redox potential of enamel, allowing proper polymerization of resin materials
Step 3: Evaluation of Options.
(A) Sodium ascorbate: CorrectIt reverses the compromised bond strength by neutralizing residual oxygen
(B) Citric acid: It is an acid etchant but does not neutralize free radicals
(C) EDTA: A chelating agent mainly used for smear layer removal in endodontics
(D) Sodium bicarbonate: Used as a cleansing or buffering agent but does not restore bond strength post-bleaching
Step 4: Conclusion.
Therefore, sodium ascorbate is effective in restoring enamel bond strength of composite resin after bleaching