The Dry-Heat sterilization process is accomplished by conduction; that is where heat is absorbed by the exterior surface of an item and then passed inward to the next layer. Eventually, the entire item reaches the proper temperature needed to achieve sterilization. The proper time and temperature for Dry-Heat sterilization is 160 °C (320 °F) for 2 hours or 170 °C (340 °F) for 1 hour.[citation needed] Instruments should be dry before sterilization since water will interfere with the process. Dry-heat destroys microorganisms by causing coagulation of proteins.
The presence of moisture, such as in steam sterilization, significantly speeds up heat penetration.
See also: Moist heat sterilization
There are two types of Hot-Air convection (Convection refers to the circulation of heated air within the chamber of the oven) sterilizers:
Gravity convection
Mechanical convection