Ultrasonic cleaners have played a part in the ever increasing awareness of hygiene in dental surgeries and now we have the publication of the weighty document known as HTM01-05 (decontamination in primary care dental practices). The complete document is quite lengthy (and dull!) and so I have only copied the section relating to ultrasonic cleaners. At first glance the procedures looks quite complicated and time consuming. However, the bulk of the text outlines simple common sense routines and best practises that most dental surgeries will already have in place.
The full publication is 98 pages long and if you really can't get to sleep one evening, read it HERE and I'm sure you will be fast asleep in no time at all. :-)
Disclaimer: the extract below is from the main publication that might have had an addendum or updates since the time of copying and so for a definitive version, please check the UK Government website for the latest version.
3.25 Evidence on the effectiveness of ultrasonic cleaning gives support to its use in dentistry. However, it is important to ensure that the water/fluid is maintained, cleaned and changed at suitable intervals (see paragraph 3.30k). The bath should also be kept free of dirt released in the cleaning process. Good maintenance is also essential. The appearance of instruments following ultrasonic cleaning should be checked to ensure that the process is operating effectively (see also Section 3).
3.26 Ultrasonic cleaning in a well-maintained machine enhances removal of debris. Thus, although a washer-disinfector is preferred and should be incorporated into new plans or upgrades, an ultrasonic cleaner can be used as a cleaning method – including being used as an extra cleaning stage prior to an automated washer-disinfector process. This may be particularly helpful for instruments with hinges and/or intricate parts.
3.27 To enable consistent cleaning of instruments, follow the manufacturer’s operating instructions and ensure that all staff use a specified and documented operating procedure. Details on validating ultrasonic cleaners are supplied in Section 3.
3.28 The use of ultrasonic cleaners to clean dental hand-pieces should not be undertaken without confirmation from the manufacturer that the devices are compatible.
3.29 The ultrasonic cleaner should be tested according to the manufacturer’s instructions or, in the absence of these, quarterly (see Section 3, Chapter 14). Ultrasonic cleaning procedure
3.30 The following procedures should be followed:
- Instruments should be briefly immersed in cold water (with detergent) to remove some of the blood and other visible soil before ultrasonic cleaning. Care should be taken to minimise aerosol production in this process and to safeguard against inoculation injury. The use of a purpose-designed container with sealing lid is recommended.
- Follow the manufacturer’s recommendations for the safe operating procedure of the ultrasonic cleaner and follow the points outlined below regarding loading and unloading the cleaner.
- Ensure that joints or hinges are opened fully and instruments that need taking apart are fully disassembled before they are immersed in the solution.
- Place instruments in a suspended basket and fully immerse in the cleaning solution, ensuring that all surfaces are in contact with the solution. The solution should be made up in accordance with the manufacturer’s instructions.
- Do not overload the basket or overlap instruments, because this results in poor cleaning and can cause wear to the instruments.
- Do not place instruments on the floor of the ultrasonic cleaner, because this results in poor cleaning and excessive instrument movement, which can damage the instruments.
- To avoid damage to delicate instruments, a modified basket or tray system might also be necessary depending on operational requirements.
- Set the timer to the correct setting as per the ultrasonic cleaner manufacturer’s instructions. Close the lid and do not open until the cycle is complete.
- After the cycle is complete, drain the basket of instruments before rinsing.
- Change the solution when it becomes heavily contaminated or otherwise at the end of every clinical session, because the build-up of debris will reduce the effectiveness of cleaning. Ensure that staff are aware of the need to assess when a change of solution is necessary as advised in the operational requirements.
- After ultrasonic cleaning, rinse and inspect instruments for cleanliness, and where possible check for any wear or damage before sterilisation.
3.31 Instruments cleaned in an ultrasonic cleaner (or by hand) should be rinsed thoroughly to remove residual soil and detergents. A dedicated sink or bowl (separate from the one used for the original wash) should be used, and the instruments immersed in satisfactory potable water or, where this is not available, in RO or distilled water. Wash hand basins should not be used. (This step may be omitted if the local policy and procedure involves the use of a washer-disinfector as the next stage in the decontamination process.) Note Hard-water contamination of wet instruments, which then go on to sterilisation, can compromise the proper function of a small steam steriliser. Advice should be sought from the manufacturers. When potable water is used, a water softener device may be needed (see paragraphs 17.8–17.10).
3.32 Instruments should be sterilised as soon as possible after cleaning to avoid air-drying (which can result in corrosion and/or microbial growth). For instruments processed in a vacuum steriliser, before being wrapped, instruments should be dried using a disposable non-linting cloth. Manual cleaning
3.33 In principle, manual cleaning is the simplest method to set up, but it is hard to validate because it is difficult to ensure that it is carried out effectively on each occasion.
3.34 Compared with other cleaning methods, manual cleaning presents a greater risk of inoculation injury to staff. However, despite the limitations of manual cleaning, it is important for each practice to have the facilities, documented procedures and trained staff to carry out manual cleaning as a backup for when other methods are not appropriate.
3.35 For dental services that are working to the best practice requirements outlined in this document, manual cleaning (acceptable under the essential quality requirements) should only be used for equipment that cannot be cleaned by automated methods.
3.36 This method should have systems in place to avoid re-contamination of clean instruments. 3.37 An effective system for manual cleaning should be put in place, as outlined in Section 3, and all staff should follow an agreed written procedure. A visual inspection for cleanliness, wear and damage should be carried out.
3.38 Consider routinely using an automated method (for example a washer-disinfector). Aim to phase in instruments that can be cleaned in a washer / disinfector.
Avoiding instrument damage.
3.39 Most dental instruments are made of high-quality materials designed to minimise corrosion if reprocessed correctly. The corrosion resistance is based on their alloy composition and structure, which forms a protective passivation layer on the surface. The ability of the instruments to resist corrosion depends on the quality and thickness of this layer.
3.40 It is important to avoid damage to the passivation layer during cleaning. Accordingly, methods such as the use of wire brushes, which may give rise to surface abrasion, should be avoided.
3.41 Any instruments that have rust spots should be removed. Cleaning procedure summary
3.42 Effective cleaning of dental instruments before sterilisation is of the utmost importance to reduce the risk of transmission of infectious agents.
3.43 Research suggests that instruments cleaned as soon as possible after use are more easily cleaned than those left for a number of hours before reprocessing.
3.44 Instruments should be transferred from the point of use to the decontamination areas as soon as is practical to ensure that processing takes place as soon as possible after use. Evidence indicates that keeping instruments moist after use and prior to decontamination improves protein removal and overall decontamination outcomes.
3.45 It should be noted that certain solutions are corrosive to stainless steel instruments and will cause pitting and then rusting if allowed to remain on instruments for any length of time. Dental Decontamination: Health Technical Memorandum 01-05 – Decontamination in primary care dental practices (2013 edition) 3 Cleaning instruments 20 21 professionals should consult with the suppliers/ manufacturers of decontamination agents to ensure that the products used are appropriate and unlikely to cause significant long-term corrosion (refer to COSHH for further advice).
3.46 Always check packaging for the single-use symbol before use and note that it might be difficult to see.
Rinsing of instruments after cleaning and or disinfection.
3.47 Instruments cleaned in an ultrasonic cleaner (or in addition by hand) should be rinsed thoroughly in a dedicated sink or bowl (separate from the one used for the original wash) using satisfactory potable water, or freshly prepared RO water or distilled water in order to remove residual soil and detergents with minimum risk of salt deposition. Note This step may be omitted if the local policy and procedure involves the use of a washer-disinfector as the next stage in the decontamination process.
3.48 Instruments should be sterilised as soon as possible after cleaning to avoid air-drying (which can result in corrosion and/or microbial growth). However, where instruments are to be wrapped prior to vacuum sterilisation, the instruments should be dried.