N, S, or B Class Autoclave?

Autoclave Type:

Class N. A class N autoclave is the lowest class device. This type can be used only as an auxiliary unit. 

The sterilization process of this class is different since it does not have a vacuum pump (which is present in higher class autoclaves), so you can only sterilise instruments with a solid structure within this device. It is also not possible to sterilise hollow-body instruments or sterilise items in packages. Class N sterilisers also do not have an effective drying option, unlike more advanced autoclaves.

Class S. Class S autoclaves are a cut between Class N and B autoclaves. 

Class S allows the sterilisation of single-packed, multilayer packed and more massive instruments, which you cannot sterilise in class N autoclaves. Autoclaves of this class have a vacuum pump, making it possible to remove the air from the chamber altogether before starting the sterilization process. However, only a single-stage pre-vacuum is used here; it is less effective than the vacuum used in class B autoclaves.

Class B. A class B autoclave is the most advanced autoclave type. 

These are what hospitals, medical centres, and dental clinics use for their instruments. They also meet all the sanitary-epidemiological requirements. They can sterilise all types of batches, even the most complex ones. Thanks to fractionated pre-vacuum, the Class B autoclave completely removes air from the chamber. It is considered the most effective and modern sterilisation technique of all types of tools.