Which is the BEST agent for disinfecting smooth, hard surfaces in the dental operatory?

Correct answer: C. 70% isopropyl alcohol

• A. High-concentration phenol is corrosive and has been replaced by safer alternatives in modern dental offices.
• B. Quaternary ammonium compounds (quats) are used for intermediate-level disinfection and are effective but may have limited efficacy against non-enveloped viruses.
• C. Correct. 70% isopropyl alcohol (or 70–90% ethanol) is the most recommended disinfectant for smooth hard surfaces in the dental office. It is rapidly effective against bacteria, viruses, and fungi on non-porous surfaces.
• D. Lysol contains phenolic compounds; while effective, isopropyl alcohol specifically is the CDC-recommended agent for smooth hard surfaces in healthcare settings.