Autoclave Class B and Class B,which one is best?

Autoclave Class B and Class B,which one is best?

Class B, without question. The choice between B and N is not about which is "better" in a general sense—it is about whether your instruments require wrapped storage or have hollow channels. If either applies, Class N is not merely inferior; it is unsuitable.

The technical difference is air removal. Class N sterilizers use gravity displacement, allowing steam to push air out passively. This works only for solid, unwrapped instruments placed directly on a tray. Class B sterilizers use a fractionated pre-vacuum pump that actively extracts air from the chamber and the load itself. Steam can then penetrate packaging, porous materials, and narrow lumens.

Why this matters clinically. A wrapped instrument processed in a Class N unit may emerge with residual air trapped inside the pouch or lumen, creating a cold spot where sterilization fails. One study found that Class N autoclaves failed to completely sterilize dental handpieces even after extended cycles, particularly inside air channels and chuck levers. Class B consistently achieved spore inactivation in the same devices.

The practical rule is straightforward. If you process only unwrapped solid tools that will be used immediately, Class N is adequate and cheaper. For dental handpieces, surgical kits, or anything pouched for storage, Class B is the only compliant option under EN 13060. The cost difference is real, but so is the risk of a failed cycle you cannot see.