What is the pressure of a dental autoclave? [Unveiling the core data guide]

The pressure in a dental autoclave is a critical factor in the steam sterilization process, working in conjunction with temperature to ensure thorough instrument cleanliness.

● Relationship between Pressure and Temperature:

In the sealed container of an autoclave, pressure is not an end in itself, but rather a means of raising the boiling point of water and the temperature of the steam. Under normal conditions, water boils at a lower temperature, but by increasing the pressure, water can remain liquid and reach higher temperatures, thus producing superheated steam.

● Conditions for Sterilization:

Achieving effective sterilization requires a specific high-temperature steam environment. There are typically two main temperature cycles, each corresponding to a certain pressure:
Lower Temperature Cycle: This usually employs a relatively moderate temperature setting, corresponding to a specific medium pressure level. This cycle is typically used for items that cannot withstand extremely high temperatures.
Higher Temperature Cycle: This uses a higher temperature setting, therefore requiring higher pressure to maintain that temperature. This cycle can complete sterilization in a shorter time and is suitable for most dental instruments.

● Importance of Pressure:

Pressure ensures that high-temperature steam can penetrate into packaged instruments, even into the crevices of complex structures, thus killing all microorganisms and spores. If the pressure is insufficient, the temperature and penetration power of the steam will decrease, and the sterilization effect cannot be guaranteed.

● Pressure Changes During Operation:

Throughout the sterilization cycle, the pressure is dynamic:
Pressure Increase Phase: The machine begins heating, water turns into steam, and the pressure rapidly increases until it reaches the preset sterilization pressure.
Maintenance Phase: The pressure and temperature are stably maintained at the set values ​​for a period of time; this is the actual sterilization phase.
Pressure Release Phase: After sterilization is complete, the pressure is slowly released until it balances with the external atmospheric pressure, at which point the autoclave can be safely opened.
Special Pressure Operations: Some modern dental autoclaves also utilize vacuum or negative pressure technology to remove air from the chamber and moisture from the instruments before or after steam entry. This helps the steam to better contact all surfaces and improves drying efficiency.