What are the standard autoclave cycles used for laboratory sterilization?

• A. 110°C for 60 minutes
• B. 95°C for 15 minutes
• C. 134°C for 30 minutes
• D. 121°C for 15–20 minutes

Answer: (D)

Sterilization with an autoclave relies on moist heat under pressure to reliably kill microorganisms, including spores. The standard laboratory cycle used in many dental settings is saturated steam at about 121°C under around 15 psi, with a dwell time of roughly 15–20 minutes. This combination provides proven effectiveness across typical instrument loads while keeping cycle times practical and materials safe. Lower temperatures such as 110°C or 95°C don’t reach the heat needed to guarantee spore destruction within a reasonable period. A higher-temperature cycle like 134°C is used in some rapid or specialized cycles, but it’s not the baseline standard for routine sterilization. That’s why 121°C for 15–20 minutes is the best answer.