What best describes autoclave sterilization?

• A. Uses dry heat sterilization
• B. Basic principle of steam sterilization accomplished with autoclave (temperature, pressure, time)
• C. Relying on UV exposure
• D. Uses chemical sterilants

Answer: (B)

Autoclave sterilization is based on moist heat delivered as saturated steam under pressure, using a precise combination of temperature, pressure, and time to achieve true sterilization. The steam transfers heat very efficiently and, when applied under pressure, reaches temperatures well above boiling. This higher heat in a short time denatures proteins and destroys all microorganisms, including spores, even in wrapped or hollow instruments. A typical cycle pushes steam to around 121°C (250°F) at about 15 psi for a set duration, though exact times vary by instrument type and load. Because it relies on steam and pressure, it’s fast, reliable, and widely used for many PMU tools.

Dry heat uses hot air instead of steam and generally requires longer cycles and higher temperatures, making it less suitable for many PMU instruments. UV exposure is limited by poor penetration and cannot reliably sterilize complex loads. Chemical sterilants sterilize by immersion in liquids and are a different method, not the autoclave’s steam-and-pressure approach.