Why is vital bleaching (for example with carbamide peroxide) generally carried out BEFORE placing a definitive anterior restoration?

Correct answer: A. Because restorative materials do not lighten with bleaching, the final shade must be selected against the bleached tooth

• A. CORRECT. Bleaching agents lighten TOOTH STRUCTURE only; composite, porcelain and cements do not change shade. If the restoration is placed first and the teeth are bleached afterwards, the restoration is left conspicuously darker than its surroundings and must be replaced. Bleach first, allow the shade to stabilise, then select the shade and restore.
• B. Bleaching commonly CAUSES transient sensitivity rather than reducing it; potassium nitrate and fluoride are used to manage this.
• C. Bleaching has no meaningful anticariogenic effect at the restoration margin.
• D. Bleaching does the opposite in the short term. Residual peroxide and released oxygen INHIBIT resin polymerisation and reduce bond strength — which is precisely why a waiting period is required.

Note: Wait AT LEAST two weeks after the last bleaching session before bonding. This allows residual peroxide to dissipate (restoring bond strength) and allows the shade to rebound slightly and stabilise, so you are matching the true final colour.