Name two sterilization methods suitable for heat-sensitive instruments.

• A. Autoclaving and dry heat
• B. Ethylene oxide (EO) and hydrogen peroxide-based sterilization (gas plasma or vapor)
• C. Pasteurization and cold sterilization
• D. Ultraviolet light and gamma irradiation

Answer: (B)

Heat-sensitive instruments must be sterilized with methods that operate at low temperatures, so no heat is required to achieve sterility. Ethylene oxide gas sterilization is a classic low-temperature option that penetrates packaging and complex instruments, making it suitable for plastics and delicate components. It does require a proper aeration phase afterward to remove toxic residues. Hydrogen peroxide–based sterilization, including vapor or plasma forms, also works at low temperatures and tends to have quicker cycles with minimal residue, though each device must be evaluated for material compatibility and whether the instrument’s lumens can be effectively reached. In contrast, high-heat methods like autoclaving or dry heat would damage heat-sensitive tools, and options like pasteurization are not full sterilization while UV and gamma irradiation have limitations in penetration or are used in specialized contexts.