Which agent is appropriate for disinfecting an alginate impression?

Correct answer: A. Diluted sodium hypochlorite

• A. ✅ CORRECT — An intermediate-level disinfectant is required. Diluted SODIUM HYPOCHLORITE (typically 1:10 household bleach) is the standard choice for alginate — sprayed or briefly immersed, then bagged for the contact time. Iodophors and some glutaraldehyde formulations are alternatives.
• B. ❌ Alcohol evaporates too quickly to achieve the necessary contact time and distorts some impression materials.
• C. ❌ 3% hydrogen peroxide is a low-level antiseptic, not an accepted impression disinfectant.
• D. ❌ Sterile water cleans but does not disinfect.

Note: Alginate is hydrophilic — prolonged immersion causes imbibition and distortion. Spray-and-bag is preferred, and the impression should be poured within 10–15 minutes.