De-mystifying decontamination

09 May 2011
Volume 27 · Issue 5

Peter Bacon reviews the HTM 0105 guidelines.

With increased awareness of HTM01-05 guidelines and the plethora of cleaning methods and materials required to achieve compliance, it is easy for practice managers, nurses and dentists to be confused by the regulations and the choice of products that will be most effective in ensuring the health and safety of staff and patients.

As detergents and surface cleaners are in daily use, the demand for solutions that are pH neutral and alcohol-free is growing, as these products are widely perceived as being less aggressive to the materials and surfaces they are cleaning and to the staff who are using them. It is also worth noting from an economic point of view only CE marked products designed for use on medical devices should be used and failure to do so may invalidate warranties.

Although the use of a washer disinfector is recognised as being the preferred method of ensuring decontamination protocols are adhered to, HTM01-05 also recognises that ultrasonic and manual cleaning have a role to play in the dental practice.

Ultrasonic means 'above the frequency range detectable by the human ear'. Ultrasonic cleaning involves transducers which transmit high frequency vibration (>20kHz) to the cleaning solution. This technique is particularly good for particulate removal and the addition of a neutral or alkaline detergent enhances the cleaning properties.

Manual cleaning, although not as effective as ultrasonic or washer disinfectors and despite the fact it poses a higher risk of injury, remains an often used method of cleaning instruments. HTM 01-05 (16.3) gives guidance that manual cleaning requires the use of an effective neutral detergent and should not involve the use of chlorhexidine based scrubs (chlorhexidine causes proteins to stick to steel), washing up liquid, cleaning creams or soap.

The process of detergency itself is straightforward; in both manual and ultrasonic processes, a combination of 'wetting' (to reduce surface tension) and detergents, helps to release soils from surfaces, they are then kept in suspension by the right blend of surfactants and other cleaning components, preventing re-deposition on the cleaned surface.

The detergents used are specially formulated for either manual or ultrasonic cleaning and as technology advances so the effectiveness of detergents increases, for example, by harnessing the benefits of enzymes. Dentizyme is one such detergent which can be used for both manual and ultrasonic instrument cleaning. The presence of an enzyme blend acts as a biological catalyst that speeds up the chemical breakdown of proteins present into smaller units that can be more easily removed from the surface of instruments.

The immediate cleaning and sterilisation of dental instruments after use is the most effective way to ensure decontamination guidelines are met, but practicality means that for many practices this is untenable. HTM01-05 Section 3.5 states: 'Instruments cleaned as soon as possible after use may be more easily cleaned than those left for a number of hours before reprocessing. Where this is not possible, water immersion or the use of a foam spray intended to maintain a moist or humid environment are thought useful in aiding subsequent decontamination.'

Evidence to support this recommendation in the form of a paper by Lipscomb, Pinchin, Collin and Keevil (2007), found that pre-soaking instruments significantly reduced (by up to 96 per cent) prion-infected tissue contamination by helping to maintain a moist, humid environment which is an aid to decontamination. They concluded that allowing a contaminant to dry onto an instrument surface for any length of time could severely hamper its removal and thereby reduce the effectiveness of subsequent sterilisation procedures.

Dentifoam from Dentisan is one such material; a ready to use, non-hazardous, water-based liquid that keeps soiled instruments moist prior to decontamination and disinfection. The foam is sprayed directly onto soiled instruments, but then rapidly breaks down, leaving surfaces coated in liquid. As soon as the foam comes into contact with the instruments, the decontamination process starts as it helps to loosen debris. Because it contains a non-drying component, it prevents blood and tissue and so on from becoming 'dried-on' to the instruments' surface. Once instruments are ready to be cleaned, the foam is simply rinsed away using water, leaving instruments ready to be cleaned.

Decontamination guidelines also cover the use of hard surface cleaners and HTM01-05 Section 6.61 states: 'The patient treatment area should be cleaned after every session using disposable cloths or clean microfibre materials - even if the area appears uncontaminated.'

Using an effective disinfectant wipe or cleaner is important to ensure the risk of cross infection is minimised. Many disinfectants on the market are unable to penetrate oils, fats and protein-based materials so do not disinfect effectively in areas where these are present. The best type of disinfectant to use is one that cleans and disinfects in a single operation using an alcohol free, wide spectrum biocide that is proven effective against MRSA, C Difficile, hepatitis B and C, HIV, tuberculosis and Norovirus. This will give you the peace-of-mind that disinfection in all areas of your practice meets 'best practice' protocols.

The need for rigorous decontamination procedures in the dental practice is self-explanatory and safeguarding the well-being of staff and patients should be uppermost when selecting equipment and materials that will ensure compliance. As those responsible for ensuring practices observe and comply with the latest guidelines it is important practice managers and dentists have a clear understanding of what is required.