How well do you know your autoclave types?


  Posted by: Dental Design      13th April 2023

Cleaning, disinfection and sterilisation is vital to ensure your dental instruments are safe for use. Equipment such as autoclaves, which were first developed in 1879, are now available in a range of models, varying in size, performance and capabilities. According to HTM01-05, [i] ‘B’ and ‘N’ type units are the most frequently used in dental practices, but they can still vary in quality and ability, so it is important to choose an appropriate autoclave for your needs.

‘B’ type autoclaves

‘B’ type autoclaves are considered the ideal autoclave type for the sterilisation of wrapped or unwrapped instrument. With a type ‘B’ autoclave, you can sterilise solid, porous items and hollow instruments.

These systems operate a vacuum pump, completely removing air from their chamber to allow the steam to penetrate the load more successfully. ‘B’ type autoclaves initially remove almost all air from the chamber and load, then inject small bursts of steam until the pressure and temperature of the chamber reaches the sufficient conditions for the sterilisation process to begin, being held for the duration of the sterilisation time (holding time). After the sterilisation process completes, the exhaust valve will release the pressure and steam inside the chamber to an atmospheric pressure. Next, the drying phase commences, with the vacuum pump sucking out the moisture. The load is then ready to be removed and used immediately or placed into storage (pouched items can be stored for up to one year).

‘N’ type autoclaves

Class ‘N’ autoclaves are non-vacuum units that work by utilising steam from a boiler or generator and creating a downward displacement, pushing air from the chamber. These autoclaves are able to sterilise solid, unwrapped instruments. When the load has finished, HTM01-05 guidelines state that the items should be aseptically wrapped. They can then be stored for up to one year.i However, they can also be used straight away, stored unwrapped and dry in the clinical area for a maximum of one day, as long as they are dry and protected from contamination. Additionally, they can be stored, unwrapped and dry, for up to one week in a non-clinical area.

When the sterilisation process begins, steam pushes the air from the air jet, where the sterilisation temperature is then reached (or, ‘holding time’). The pressure is removed back to an atmospheric pressure through the exhaust valve, in the same fashion as a ‘B’ type unit. Lastly, the drying stage is achieved either with an aeration pump or simply opening the autoclave door. While not able to sterilise quite as many different items as a ‘B’ type autoclave, ‘N’ type units are still able to sterilise unwrapped items.

What should I choose?  

If you are in a position where you require a new autoclave for your practice, you may be wondering which unit to choose. ‘B’ and ‘N’ type autoclaves can both benefit a dental practice, as they provide different benefits that depend on the size and workload of the business. When making a decision, it is worth considering the capacity and chamber size of the unit, and whether this can support your practice’s daily work. If you require a smaller quantity of instruments to be sterilised, then a larger model may not be an efficient option. Likewise, if the unit is too small, then the dental team will have to reprocess instruments more often.

It is essential that the maintenance and repair services offered by the manufacturer are taken into account – this can add incredible value to your investment and you can gain the peace of mind that, if a breakdown were to occur, you are covered.

The best of both

Eschmann offers professionals a range of ‘B’ and ‘N’ type autoclaves such as the Little Sister SES 3020B vacuum unit, which includes the choice of both ‘B’ and ‘N’ type cycles in one autoclave. This means you have the flexibility to choose a cycle that suits your needs. The 23-litre capacity chamber allows for more instruments to be processed at one time, increasing practice efficiency.

Eschmann also provides Care & Cover, an essential service contract for Eschmann equipment. Some of the benefits included in Care & Cover (with no hidden costs) is Annual Validation and Pressure Vessel Certification, unlimited breakdown cover, unlimited Eschmann parts and labour in addition to enhanced CPD user training. 

All dental practices must follow strict infection control protocols, and it is important to choose an autoclave that offers you the best protection and performance, and aligns with the needs of your business.

For more information on the highly effective and affordable range of decontamination equipment and products from Eschmann, please visit or call 01903 875787

[i] (n.d.). NHS England» (HTM 01-05) Decontamination in primary care dental practices. [online] Available at: [Accessed 7 Dec. 2022].


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