Laurence Bohan
Content Writer
Laurence Bohan
Content Writer

Laurence is a copywriter and trained journalist. His passion is creating insightful and educational content for dental professionals of every level. Outside of work, he enjoys watching sport, quizzing and spending time with his family.

Whether fitting out a new practice, replacing a broken-down machine or simply upgrading, deciding on the best autoclave to buy should not be a rushed decision. As an expensive piece of equipment that plays a pivotal role in infection control, your autoclave should tick as many boxes as possible.

Our Ultimate Guide to Autoclaves will arm you with everything you need to make an informed purchase.

What is an autoclave?

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How do autoclaves work?

Autoclaves use steam to create a high-pressure environment at a temperature too high for microbial survival. This eliminates pathogens that may be resistant to soaps and detergents. The steam created in the autoclave allows for thorough sterilization within dental instruments and tiny holes and crevices that could be missed during cleaning with detergent.

  1. The first stage of the autoclave sterilization process is sometimes referred to as the “purge” phase. This is when steam created from heating water displaces the air within the autoclave chamber. Both temperature and pressure then begin to increase.
  2. The second stage is the sterilization phase. During this phase, the exhaust remains closed causing the temperature and pressure to rapidly rise to the desired levels required to destroy bacteria, spores and other pathogens.
  3. The third phase is the exhaust phase. This is when pressure is released from the chamber, but temperatures remain high.
  4. The fourth and final stage is the cooling down phase. Once temperatures are low enough, the load can be removed from the chamber ready to be reused.

Watch here how it works

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Autoclave sterilization temperature and time

The recommended temperature for optimal autoclave sterilization is between 120 and 135ºC. The duration of the sterilization phase is usually between 5 and 20 minutes but will depend on factors such as load quantity.

Explore autoclaves

What are the different types of autoclaves?

  • Air removal happens by gravity displacement where the steam pushes the air out of the autoclave.
  • Used for sterilizing only simple materials, such as scalpels, and therefore not recommended for dental practices.
  • Cannot be used to sterilize textiles, porous loads, hollow items or items in pouches as the cycles do not have the right characteristics to pass specific physical tests.
    S class autoclaves.
  • Remove the air inside the chamber using a steam wall which is denser than air. During the sterilisation cycle they perform this process three times to ensure that all the air inside the chamber is removed.
  • Selective models of S class autoclaves come with a vacuum pump, but this is not a common feature.
  • Essentially an intermediate class between N class and B class autoclaves and the characteristics are not defined by specific standards.
  • Can be used to sterilise porous bagged products but not textiles, unless upgraded to B class.
  • Usually has options for cycle programming, temperature selection and a drying mechanism to get the instruments dry.
  • The most suitable machine for a dental practices in accordance with European Standard 13060.
  • Offer great flexibility and are suitable for a wide range of settings.
  • Remove air from inside the chamber by means of a vacuum pump, creating a negative pressure that forces steam in.
  • Can be used to sterilize all loads including solids, type A hollow instruments, type B hollow instruments, textiles, porous loads and wrapped instruments, both bagged and loose.
  • Generally capable of much faster sterilization and drying cycles, enabling dental staff to work much more efficiently.

Autoclave testing

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Autoclave validation

Sterilisation process validation is a procedure for obtaining, recording and interpreting the results required to establish that the process yields reliable, repeatable load sterilisation complying with predetermined specifications for sterility. Under healthcare standards and guidelines such as BS-ENISO:13060:2014, BS-ENISO:15883:1 and HTM 01-05, revalidation should be completed annually or in accordance with the manufacturer’s recommendations.

What to consider when purchasing an autoclave

1) Capacity

Autoclave capacity, or chamber size, indicates how many instruments or pieces of equipment can be placed inside the chamber at any one time. B class autoclave capacity ranges between 8-22 litre. The larger the capacity the more expensive the autoclave and greater the energy consumption. The autoclave capacity required will depend on the requirements of an individual practice.

Some practices choose to use two smaller capacity autoclaves for faster cycle times and to allow two cycles to be carried out at once. Having two autoclaves is also practical should one break down.

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4) Traceability

One of the more recent advances in autoclave technology is the introduction of built-in USB functionality to record sterilization cycles. Most B class and S class autoclaves now have label printers that can be connected to the sterilizer for printing barcodes. This is designed for legal protection and as a way of improving your practice’s overall traceability system.

5) Repair, servicing and maintenance

The components and technology in autoclaves do fail from time to time, so it is beneficial to purchase from manufacturers who have a technical servicing department based in your country.

W&H for example has a team of factory trained field-based engineers supporting dental autoclave repairs across the UK. To ensure the autoclave is working to maximum efficiency and reduce your chances of needing a repair, autoclave cleaners can be purchased for fast, effective and easy use.

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