In the context of dental practices, “decontamination” is defined as the process by which reusable items are rendered safe for further use and for staff to handle and is required in order to minimise the risk of cross-infection between patients and between patients and staff.
Decontamination is an all-encompassing term that involves several stages; cleaning, disinfection, inspection and finally sterilisation.
The decontamination processes required within a dental practice are clearly laid out in the HTM01-05 guidelines and following these protocols is important. But so too is ensuring that the most effective types of cleaning solutions are used as part of your embedded processes.
There are three cleaning methods referred to in HTM01-05; manual, ultrasonic and cleaning using a washer disinfector.
Manual cleaning, though acceptable as a method which meets essential quality standards, is arguably the least effective and certainly the most difficult to validate and the move towards best practice recommends the use of automated processes involving washer disinfectors.
HTM01-05 recognises the effectiveness of ultrasonic cleaning and gives support to its use in dentistry. However in order to maintain standards it is imperative that the ultrasonic bath used is kept free of dirt released in the cleaning process and that the water/fluid is maintained, cleaned and changed at suitable intervals – (see paragraph 3.30 of the guidelines).
Washer disinfectors have five key processes: flushing, washing, rinsing, thermal disinfection and drying. The washing process is particularly important and uses both mechanical and chemical processes to loosen and break up surface contamination. HTM01-05 specifies that detergents used in this process must be specified by the manufacturer as being suitable for use with a washer disinfector. In addition the detergent should be non-harmful to the instruments being cleaned, so as not to cause degradation, corrosion, staining or pitting.
The guidelines accept that whichever method of cleaning is used, pre-washing may be helpful “for example in the removal of tenacious dental materials”. They also recommend that instruments are cleaned as soon as possible after use.
If instruments are left before cleaning, removal of residual contamination can be difficult, and as tissues contain salts that can discolour and cause instruments to rust, there is an increasing likelihood of mechanical failure.
Where cleaning immediately after use is impractical due to time pressure or surgery layout, the guidelines recommend that instruments are pre-soaked in either water or in a specifically designed foaming solution as an additional method of ensuring cleaning processes are effective.
In a paper published in 2007, it was found that pre-soaking instruments significantly reduced (by up to 96 per cent) prion-infected tissue contamination, and HTM01-05 guidelines clearly recommend the pre-soaking of instruments, to help maintain a moist, humid environment which is an aid to subsequent cleaning: “…water immersion or the use of commercial gels/sprays may be considered. These measures reduce the absorption of proteins to the instrument surfaces and makes cleaning easier.”
Once instruments are ready to be cleaned, using whichever method is your preference, the detergents used to aid the cleaning process can have a big impact on the effectiveness of the whole decontamination process.
The surfactant ingredients in detergents act to lower the surface tension of water, essentially making it ‘wetter’, so that it is less likely to stick to itself and more likely to interact with oil and grease.
The wetting of the surface allows the cleaning solution to penetrate under oily or particulate soils. The detergent itself has little impact on the soil until some mechanical energy or agitation is added to the equation, for example brushing under the water surface, this enables the detergent to release soils from the instruments’ surface.
Once a soil has been lifted from the surface, the correct blend of surfactants and other cleaning components need to combine in order to prevent re-disposition on to the cleaning surface and is subsequently carried away in the rinsing solution.
There are a wide variety of cleaning products available for use as part of decontamination protocols and are chosen according to a practice’s personal preference. pH neutral products are becoming increasingly popular, thanks to their ‘green’ credentials and the perception that they are more user-friendly than harsh chemical based cleaners. The effectiveness of these detergents, particularly enzyme-based products that naturally and effectively degrade protein-based stains such as blood, is now widely recognised.
In addition, some detergents are suitable for manual and ultrasonic cleaning methods reducing the need for additional inventory and providing a flexible solution for practices that may use a combination of cleaning methods.
For washer disinfectors, practices should select a detergent specifically formulated for this use. A low foam, low residue detergent is likely to be most effective along with a compatible rinsing agent that dries rapidly to a clear finish giving instruments a clinical ‘sparkle’ that visually reassures patients of cleanliness. It is important that detergents and rinsing agents used in washer disinfectors are formulated to operate effectively in hard and soft water, helping to resist scale build-up in rinse jets and pipes and thereby avoiding unnecessary maintenance issues.
Following cleaning, inspection is required in the first instance to ensure that the standard of cleaning achieved is visually satisfactory and particulate contamination is not visible to the naked eye. It is recommended that the use of a simple magnifying device with additional lighting vastly improves the value of this aspect of the process.
The effective cleaning of instruments is an essential prerequisite of the decontamination process before sterilisation takes place. Due to the high temperatures involved, the process of sterilisation ‘bakes on’ any remaining contaminants and soils that have failed to be removed during the cleaning process, thereby rendering any unclean instrument unable to be satisfactorily sterilised.
The choice of detergents used in instrument cleaning can be overlooked, as practices often concentrate on processes rather than materials. However effective cleaning is the foundation for the whole decontamination process and choosing detergents that are suitable, effective, have no adverse impact of the instruments themselves and are safe for the staff using them daily, can fundamentally speed up decontamination processes and assures those responsible that full compliance is maintained.
References available on request.