Suture materials cannot be sterilised by which method?

• A. Steam
• B. Ethylene oxide
• C. Dry heat
• D. Chemical

Answer: (D)

Suture sterilization must preserve the fibre integrity and avoid toxic residues while reliably eliminating all microorganisms. Steam (moist heat) sterilization works well for many sutures and is fast and effective. Dry heat is suitable for heat-stable sutures when moisture could damage them. Ethylene oxide is used for heat‑sensitive sutures because it sterilizes without high temperatures, though it needs careful handling and aeration. Liquid chemical sterilants, however, can leave residues, may not penetrate filaments evenly, and can alter the suture material or provoke tissue reaction, making true, reliable sterility difficult to guarantee. For these reasons, chemical sterilization isn’t used for routine suture sterilization, so that method is considered unavailable for this purpose.