Cross Infection Control

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PracticeSafe Soak, the popular impression material disinfectant

Some existing users highlight the benefits of Kemdent's PracticeSafe Soak impression material disinfectant

Since the introduction of The Department of Health’s Decontamination Health Technical Memorandum 01-05: Decontamination in primary care dental practices both Dental Practices and Laboratories have had to review their protocols regarding infection control involving the transfer of impressions, models and removable appliances (including crowns, bridges and dentures etc). This is because, on page 42, it states that all impressions, prostheses and orthodontic appliances must be "decontaminated in a multi-step process to be conducted in accord with the device or material manufacturer’s instructions".PracticeSafe Impression Soak Pouring

Supplied in a concentrated form, PracticeSafe Soak has been specifically designed to meet all the requirements of HTM 01-05 and all the other relevant regulations and standards regarding the disinfection of impression materials, prostheses and orthodontic appliances within the Laboratory environment.

In its recommended 3% working concentration, after removing any debris under running water, only 3 minutes immersion is required. This is dramatically less than the 10 minutes recommended by the manufacturers of many of the other products currently available on the market. This means that the risk of alginate and polyether impressions becoming distorted due to water absorption is minimised. It also saves time for Technicians, who are often in a hurry and do not want to waste time waiting around while an impression soaks for the right duration, often resulting in inadequate disinfection.

The active ingredients in PracticeSafe Soak are Alkyldimethylbenzyl Ammonium Chloride and Didecyldimethyl Ammonium Chloride, without any of the degreasers or alcohols present in other materials. The combination of all three means that PracticeSafe Soak is effective against bacteria (including MRSA) and fungi (including yeasts) and lipid enveloped viruses.

PracticeSafe Soak is supplied in a concentrated liquid presentation which is easily diluted in water to produce a 3% working solution, which should be changed daily or when it has become visibly contaminated. 30ml of PracticeSafe Soak making 1 litre of solution in which to soak the impressions (alginate, polyether, addition silicone etc), acrylic dentures and even waxes during the try-in stage. For details of the dilution rates for different volumes of PracticeSafe Soak please see Table 1 below.

PracticeSafe Soak Table 1





Following the instructions for use is extremely important

In order to obtain optimum results from this product it is essential to follow the manufacturer’s instructions correctly.

The first step is to produce a proper 3% solution using the refillable dosage bottle. To achieve this easily and accurately the cap of the dosage bottle is opened by half a turn. The body of the bottle is then squeezed until the required 30ml of concentrated PracticeSafe Soak fills the dosage chamber. This 30ml of Practice Safe Soak is then poured out into an impression bath containing 970ml of water to create 1 litre of 3% PracticeSafe Soak. Always add the concentrate to the water and ensure it is mixed well. Avoid excess foaming.

If 2 litres of 3% PracticeSafe Soak is required add 60ml of concentrate to 1 litre 940ml of water to make 2 litres of working solution. For 4 litres add 120ml of concentrate to 3 litres 880ml of water and so on. Therefore, one litre of PracticeSafe Soak concentrate will make 33 litres of 3% PracticeSafe Soak solution.

Should the dosage chamber of the dosage bottle ever become overfilled it can be emptied again by closing the cap of the dosage chamber, loosening the filling cap, squeezing the body of the bottle to create a vacuum which sucks out the concentrate from the dosage chamber, closing the filling cap and tilting the bottle slightly. Once the dosage chamber has emptied the dosage cap can be reopened and squeezing the body of the dosage bottle will dispense the correct amount (30ml) into the dosage chamber ready for dispensing.

The second step is to rinse the impressions with clean running water thoroughly to remove any visible contamination such as blood and saliva. Completely immerse the impression and tray in the 3% PracticeSafe Soak solution in the impression bath for 3 minutes. After the full 3 minutes remove the impression and tray and rinse thoroughly under clean running water to remove the PracticeSafe Soak.

The manufacturers recommend that the PracticeSafe Soak solution is changed daily or when the solution is visibly contaminated. Some Technicians prefer to make up a larger quantity of 3% PracticeSafe Soak in advance and simply dispense it as and when required. This is a perfectly satisfactory thing to do.


Existing users

This is what some Technicians who have already swapped to PracticeSafe Soak had to say:-


Quote from Leon Corns CDT, Leon Corns Denture Services, Dudley:

"We switched from Impressiv universal dental impression disinfectant spray about three years ago because it was a spray and we wanted to use a soak. We also liked the fact that PracticeSafe Soak was more economical, had a nice blue colour and multiple uses. We use it to disinfect impressions in a bath for three minutes. We also have two small soak pots for denture repairs which we use to disinfect prostheses in before handling them.

On removal from the mouth impressions are inspected, then washed under running water for about 30 seconds. Then they are placed in the impression disinfection bath with the lid placed on for about 3 minutes. Once out of the impression bath they are rinsed again under running water and wrapped in a wet paper towel. These are then placed in a sealed polythene bag. The work ticket laboratory prescription is stamped as proof of being disinfected. Only then do they go through to the laboratory area.

For denture repairs, when the patient arrives we ask them to come into the clinical area and remove their dentures and place them in a small soak pot. We tell them that we need to make sure we disinfect the denture before we handle it. While in the pot we take the patient’s details and don a pair of gloves. This process takes about one minute. We then wash the denture under running water and dry it with tissue and examine the denture. This solution is changed every day or sometimes after a particularly dirty denture which has clouded the solution.

Our impression disinfection bath holds about 5 litres so the solution is changed every day, but I can see why Labs with smaller baths would use smaller quantities provided the impressions are fully immersed. The solution normally stays clear and usable all day because we wash all the impressions under running water before immersing them in the solution.

We find the dosage compartment with the ml markings on the two cap container very useful for quick preparation of solutions.

Another advantage of PracticeSafe Soak is that it costs a lot less than ready to use solutions because it is in a concentrated form. We also like the fragrance because it smells reassuringly strong. We also like its blue colour because it is a clinical colour and if it was clear we would be concerned about its concentration values."


Quote from Alex Kerr, Chilli Dental Lab, Whitley Bay, Tyne & Wear:

"I started using PracticeSafe Soak in 2014. Before that I used to use Perform ID, but I didn’t like the fact that the granules didn’t always dissolve straight away so I wasn’t sure that the solution was of the correct concentration. I like PracticeSafe Soak because it is easy to use and reliable. I use it to disinfect all my impressions and dentures requiring remedial work. I always prepare small quantities and replace it twice daily because prevention of cross contamination is of paramount importance. I don’t use an ultrasonic bath. PracticeSafe Soak costs a lot less than Perform ID too."


Quote from John Craig, Canton Dental Laboratory, Cardiff:

"We’ve been using PracticeSafe Soak for about a year now, before that we used a spray-type disinfectant but didn’t think it was as effective as a soak like PracticeSafe. We use it for all the impressions and denture repairs that come into the Lab. We change the solution every day and, after unwrapping the impression, place them in the soak for 10 minutes ready for casting up. We make up the solution when we need it and do not use an ultrasonic bath as we believe soaking them is sufficient. PracticeSafe costs about the same as the spray product we used to use. PracticeSafe has little or no fragrance and its colour is a useful aid to mixing. We find the dispensing bottle easy to use and it works well. We feel it is an effective and safe product to use."


Quote from Richard Hinley, John Foster Private Prosthetics, Swalwell:

"We started using PracticeSafe Soak about 18 months ago because we needed a more specific disinfection material for use with impressions than the normal antibacterial solution we used to use. We find it easy to use and it produces good results."



When using PracticeSafe Soak, as recommended by the manufacturer, it delivers a reliable, effective and extremely economical means of disinfecting impressions and dentures requiring repair. Kemdent recommend impressions are rinsed with clean running water to remove any visible contamination such as blood and saliva, then completely immerse the impression and tray in a 3% PracticeSafe Soak solution in the impression bath for 3 minutes. After the full 3 minutes remove the impression and tray and rinse thoroughly under clean running water to remove the PracticeSafe Soak.


To find out more about this product or to buy Click Here



Top reasons to choose InstrumentSafe

Kemdent introduces InstrumentSafe, its disinfectant that will help keep your dental equipment safe, clean and compliant

InstrumentSafe Disinfectant 1L and 5LThe Department of Health’s Decontamination Health Technical Memorandum 01-05: Decontamination in primary care dental practices describes the essential steps required for the safe and effective sterilisation of dental instruments. This includes the use of either a washer-disinfector, manual cleaning combined with ultrasonic cleaning or manual cleaning only. It stresses the importance of effective cleaning of instruments as an essential prerequisite before sterilisation because it will reduce the risk of transmission of infectious agents.

Within the Best Practice framework the use of either an ultrasonic cleaner or washer-disinfector is recommended in preference to manual cleaning only, unless the manufacturer specifies that the device is not compatible with automated processes.

Instruments should be cleaned as soon as possible after use because they 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 or gel intended to maintain a moist or humid environment are thought useful in aiding subsequent decontamination.



InstrumentSafe Disinfectant PouringSupplied in a concentrated form, InstrumentSafe has been specifically designed to meet the requirements of HTM 01-05 and all the other relevant regulations and standards regarding the disinfection of instruments prior to autoclaving within the Practice environment.

Aldehyde and Phenol-free, InstrumentSafe is recommended for the disinfection and cleaning of dental instruments including rotary instruments prior to autoclaving. It can be used with both thermo-labile and thermo-stable instruments.

InstrumentSafe is supplied in a concentrated liquid presentation, which is easily diluted in water to produce different concentration working solutions, which should be changed daily or when it has become visibly contaminated.


Feedback from existing users

This is what some practices who have already swapped to InstrumentSafe had to say:


Alex Harvey - Practice Manager - Johnstown Dental Practice, Wrexham:

"We first started using InstrumentSafe in 2012. Prior to that we used a different brand but we didn't like it because it didn't kill as many viruses as InstrumentSafe and there was a lack of support information available. It was also more expensive.

We use a 2% InstrumentSafe solution because it's stronger and therefore theoretically even more effective. We use it in an Ultrasonic bath to disinfect and clean all our instruments. We always use an Ultrasonic bath because it helps to debride the instruments, but we'd be happy to use it as an instrument soak, if left for an appropriate time, if there wasn't an Ultrasonic bath available. However in this situation we'd manually scrub the instruments first.

"We produce a fresh batch of InstrumentSafe every time we need one and change it either at the beginning of each session or when it is visibly contaminated. We find the dosing bottle very easy to use"


Jon Stark - Baddow Road Dental Surgery, Chelmsford:

"We switched to InstrumentSafe about 18 months ago. We use it to disinfect and clean all our instruments daily. We fill a sink to the level marked on the side with water and add enough InstrumentSafe to make up five litres of 2% solution. We do this daily. We find the fragrance pleasant and not overpowering"



When using InstrumentSafe, as recommended by the manufacturer, it delivers a reliable, effective and extremely economical means of disinfecting instruments that helps protect the practice staff and the patients from risk of cross infection.


For further information on Kemdent's InstrumentSafe Disinfectant please Click Here

Safe and clean...the benchmark for compliance and Best Practice

Sarah Bain, Director of the Bristol School of Dental Care Professionals, Bristol University, highlights the benchmarks by which compliance with essential quality requirements and Best Practice can be achieved regarding hard surface decontamination.

The 2013 edition of HTM - 01-15 states that, "patients deserve to be treated in a safe and clean environment with consistent standards of care every time they receive treatment.

This article will highlight the specific benchmarks by which compliance with essential quality requirements and Best Practice can be achieved regarding hard surface decontamination. By implementing these suggestions it will help the Practice demonstrate to patients that it is capable of operating in a safe and responsible manner with respect to their health and safety. It will not cover the other essential topics regarding the same aspects for personal protection and hygiene for the whole Dental Team or decontamination and sterilisation of dental instruments and other medical devices.

The information provided here also follows the essential principles given in the Health and Social Care Act 2008: Code of Practice and its 2010 revision on the prevention and control of healthcare associated infections. These principles require that effective prevention and control of healthcare-associated infections be embedded in everyday practice. Clean, safe care – reducing infections and saving lives – demands the need for high-quality environmental cleaning and decontamination as vital components in reducing rates of infection. Every practice should be capable of at the very least meeting, but preferably exceeding, the essential quality requirements. These include, among other things:-

  • Auditing their decontamination processes at least every six months using an appropriate tool.

  • Having in place a detailed plan on how the provision of decontamination services will move it towards Best Practice.

  • Having an infection-control policy in place and available for external inspection. This policy should indicate full compliance with the essential quality requirements. In addition, a written assessment of the improvements the Practice needs to make in order to progress towards meeting the requirements for Best Practice should be available together with an implementation plan too.


What does this mean within the practice generally?

Effective cleaning with ChairSafe Alcohol Free DisinfectantsAll work surfaces where clinical care or decontamination is carried out should be impervious and easily cleanable. They should be jointless as far as it is reasonable; where they are jointed, such joints should be welded or sealed. It should be ensured that all surfaces within these areas can be easily accessed and will dry quickly.

Similarly, all flooring in clinical care and decontamination areas should be impervious and easily cleanable. Carpets, even if washable, should never be used. Any joints should be welded or sealed. Flooring should be coved to the wall to prevent accumulation of dirt where the floor meets the wall.

The practice should have a local protocol clearly outlining surface- and room-cleaning schedules. The cleaning process will be most effective if the more contaminated areas are cleaned first. Materials and equipment used to clean clinical areas and other higher-risk areas should be stored separately from those used for general and non-clinical areas. Simple records should be maintained in accordance with the Code of Practice.

The use of disinfectant or detergent will reduce contamination on surfaces. The HTM - 01-15 Guidelines say that, if there is obvious blood contamination, the presence of protein will compromise the efficacy of alcohol-based wipes because alcohol has been shown to bind blood and protein to stainless steel. However, because alcohol containing disinfectants and wipes need in excess of 10 minutes’ contact time before alcohol binds proteins to stainless steel, this may not be such a problem in reality. Consequently, the use of alcohol-based disinfectants and wipes may be the best option in certain clinical situations, depending upon the nature of the surface being disinfected and personal preference.


Decontamination of treatment areas

The patient treatment area should be cleaned after every session using disposable cloths or clean microfibre materials – even if the area appears uncontaminated.

Areas and items of equipment local to the dental chair that need to be cleaned between each patient visit include work surfaces, chairs, curing lights, inspection lights and handles, hand controls including replacement of covers, trolleys/delivery units, spittoons, aspirators and x-ray units.

Areas and items that need to be cleaned after each session include taps, drainage points, splash backs and sinks.In addition, cupboard doors, other exposed surfaces (such as inspection light fittings) and floor surfaces (including those distant from the dental chair) should be cleaned daily.

Items of furniture that need to be cleaned weekly include window blinds, accessible ventilation fittings and other accessible surfaces such as shelving, radiators and shelves in cupboards. Purpose-made, disposable, single-use covers are available for many of the items mentioned above; however they should not be taken as a substitute for regular cleaning. Such covers should be removed and the underlying surfaces still cleaned after each patient’s visit.

For infection-control purposes, in clinical areas covers should be provided over computer keyboards, or conventional keyboards should be replaced with ‘easy clean’ waterproof keyboards. If covers or conventional keyboards are used, care should be taken to ensure that the covers are changed or that washing is performed at frequent intervals.

This cleaning should centre on simple techniques, using disposable cloths wetted with clean water and an appropriate detergent. Dry cleaning should be avoided wherever possible as this may result in a bacteria-laden dust suspension being distributed around the surgery.

Recommended ChairSafe Products for different surfaces












ChairSafe - alcohol-free surface disinfectant and surface disinfectant wipes

According to the manufacturer, Kemdent’s ChairSafe range of alcohol-free hard-surface disinfectants, foam and wipes have been specially formulated to clean sensitive surfaces and equipment, including the leather and synthetic facings of dental chairs. The wipes are available as single-use dry wipes for use with ChairSafe Spray or Foam, pre-impregnated economy wipes and pre-impregnated microfibre wipes.

ChairSafe Alcohol Free Disinfectant Range


Used in combination with the dry wipes, the spray delivery of ChairSafe Spray is recommended for use on large surfaces where you want to cover a large area quickly and easily, for example: work surfaces, chairs, cupboard doors, shelves in cupboards, sinks and splash backs etc. The foam, which is non-drip and remains exactly where you apply it, is said to be more suited to smaller items for example curing and inspection lights.

The pre-impregnated economy or microfibre wipes can be used as an alternative to the dry wipe / foam or spray combination. As well as being suitable for use on trolleys and shelving, they are particularly useful for disinfecting small and fiddly items for example curing lights, inspection lights, aspirators and spittoons, x-ray units, taps, draining points, window blinds, ventilation fittings and radiators.

Compared with economy wipes, microfibre wipes are larger and more heavy duty, which makes them even better for use when cleaning larger surface areas. Available as either dry wipes, for use with ChairSafe Spray or Foam, or pre-impregnated for even greater economy, microfibre wipes are designed to provide superior removal of dust, dirt and micro-organisms because they are able to attach themselves and thereby lift up even the smallest and most microscopic dirt particles.

Whichever option is chosen they are all effective against bacteria including MRSA, Pseudomonas Aeruginosa, Staphylococcus Aureus; viruses including BVDV, Vaccinia, H1N1, Hepatitis B, Hepatitis C; and Fungi. Used as recommended ChairSafe hard surface disinfectants are effective against the above pathogens in one minute.

Table 1, above, contains a summary of the surfaces that need to be disinfected either between patients, daily or weekly. It also contains our recommendations for the best combination of ChairSafe products to use for each surface.


Clinical evaluation

During our recent assessment of the complete ChairSafe range within the department we were impressed with the heavy-duty microfibre wipes. They were very easy to use, had a pleasant smell and one wipe went a long way. They spread well and did not leave a foamy residue, unlike some other products we have used. We would recommend the pre-impregnated microfibre wipes as the first product of choice for all applications, with the added benefit that you do not need to have different options for different surfaces.

The next best option for most applications was the spray with a single-use dry wipe. The spray was great to use on larger surface areas in particular because it covered the surface area the best, but we still preferred using a pre-impregnated wipe rather than a spray and wipe combination because it was easier. For smaller items we still preferred to use microfibre wipes to avoid excess aerosol use.



Having evaluated the ChairSafe range, we believe it contains everything required to enable dental practices to fulfil the requirements of the 2013 edition of HTM - 01-15 and Best Practice. In most cases our first choice of product is the pre-impregnated microfibre wipe, which is suitable for all surfaces and is quick and easy to use.

To learn more I recommend you CLICK HERE

The ChairSafe range of surface disinfectants is manufactured in the UK by Kemdent Ltd.
For further information contact Kemdent on 01793 770090


PracticeSafe Soak the ideal impression material disinfectant

Belinda Mayoh BSc and James Holder BSc from Associated Dental Products Ltd, Swindon, describe the ideal qualities for an impression material disinfectant


First the boring bit

On page 42 of The Department of Health’s Decontamination Health Technical Memorandum 01-05: Decontamination in primary care dental practices it clearly states that all impressions, prostheses and orthodontic appliances must be “decontaminated in a multi-step process to be conducted in accord with the device or material manufacturer’s instructions.

PracticeSafe Impression SoakImmediately after removal from the mouth, any device should be rinsed under clean running water. This process should continue until the device is visibly clean. All devices should then receive disinfection according to the manufacturer’s instructions. This will involve the use of specific cleaning materials noted in the CE-marking instructions. After disinfection, the device should again be thoroughly washed. This process should occur before and after any device is placed in a patient’s mouth. If the device is to be returned to a supplier/Laboratory or in some other fashion sent out of the practice, a label to indicate that a decontaminated process has been used should be affixed to the package.”

In reality this means that every time a Dentist takes a dental impression it must be thoroughly rinsed, disinfected and rinsed again before it is sent to you at the Laboratory. Likewise when you send the crown, bridge, denture or whatever other type of appliance you have manufactured within the laboratory it must be similarly disinfected and rinsed by the Dentist before it is placed in the patient’s mouth. If the appliance is then returned to the laboratory, for whatever reason, the same cycle must be repeated both before sending it back and before reinserting it into the patient’s mouth at the next appointment. This protocol must be repeated until the patient leaves the Practice with the final restoration or appliance. In between times, you will similarly be rinsing and disinfecting the impression or device upon receipt within the laboratory and before sending it back to the Practice. That’s a lot of rinsing and disinfecting!

Impression placed in a bag

Unfortunately a lot of the impression materials currently in use, especially alginate and polyether impression materials, are very moisture sensitive and so can become swollen and distorted if they remain in contact with water for too long.

Similarly, some of the disinfectants currently in use are supplied in either a powder presentation, which needs to be thoroughly dissolved if it is to have the manufacturer’s recommended concentration for effective disinfection, which may not always happen in reality, or alcohol sprays where there is an obvious health risk associated with vaporised spray, may be even incorporated bacteria etc. Consequently a burst of pressure from a spray can expel potentially harmful bacteria into the Laboratory environment, which can then possibly settle upon the surrounding surfaces and later come into contact with staff, causing a serious risk of cross contamination and infection.

The water that the impression is rinsed in must also be considered. If it is hard water, containing various calcium and magnesium impurities, these can be deposited on the surface of the impression acting as a barrier between the impression surface to be disinfected and the disinfecting agent itself. It is also well documented that these impurities reduce the effectiveness of some disinfecting chemicals, themselves, by forming chemical bonds and essentially deactivating them.

Therefore the ideal Impression Material Disinfectant should have the following properties:-

Meet all the requirements of HMT 01-05 etc with regard to the disinfection of impression materials, prostheses and orthodontic appliances

- Safe to use – containing no allergenic or components hazardous to health

- Short working time – to avoid excessive water contact

- Easy to use

- Liquid rather than powder presentation – easy to mix in the correct proportions

- Effective in hard water

- Cost effective

There are now products on the market which, when used in the appropriate concentration in an ultrasonic bath to maximise contact with the impression material’s surface, require only 3 minutes immersion time. This is dramatically less than the 10 minutes recommended by the manufacturers of other products. This means that the risk of alginate and polyether impressions becoming distorted due to the water absorption is minimised. It also saves time for Technicians, who are often in a hurry and do not want to waste time waiting around while an impression soaks for the right duration, often resulting in inadequate disinfection.


These new products frequently contain different active ingredients. For example, they may contain a blend of Benzalkonium Chloride, Didecyldimethyl Ammonium Chloride and Borax. Benzalkonium Chloride is extensively used in First Aid Kits for the treatment of cuts, cold sores and blisters, but it has been tested and approved for use in the Food Industry (1), consequently it is safe for use within the Dental Industry too. Didecyldimethyl Ammonium Chloride provides an additional bacteriostatic and bactericidal effect. Finally, Borax or Sodium Borate is a naturally occurring mineral compound which helps disinfect the impression surface due to the formation of Hydrogen Peroxide. It also acts as a natural water softener, acting against the calcium and magnesium impurities found within hard water, thereby boosting the disinfecting efficiency of the Benalkonium Chloride and Didecyldimethyl Ammonium Chloride. The combination of all three makes the impression material disinfectant effective against bacteria (including MRSA) and fungi (including yeasts) and lipid enveloped viruses.

Frequently they are also manufactured without any of the degreasers or alcohols present in other materials.

Many of these products are supplied in a concentrated liquid presentation which is diluted in water to produce a working solution, which should be changed daily or when it has become visibly contaminated.

1. The Disinfectant Effects of Benzalkonium Chloride on Some important Foodborne Pathogens. American –Eurasian J.Agric. & Environ. Sci., 12 (1): 23-29, 2012

To find out more about PracticeSafe Impression Soak Click Here

The essentials of disinfection and decontamination


Kathy Porter, Senior Dental Nurse (Decontamination) at Birmingham Dental Hospital, highlights her perception of “Best Practice” for disinfection and decontamination within Hospital and General Practice environments


Infection prevention and control is the single most important practice that all the dental team are involved in. It is important to emphasise that infection prevention and control is the responsibility of everyone, not only within the team but also the people that visit the surgery and they should have every encouragement to participate in good practice. This can be achieved by promotional material on view and the evidence that your practice is actively involved in ensuring its patient health and wellbeing.

The General Dental Council (GDC) recognises the importance of this subject by making it a compulsory subject for Continuing Professional Development (CPD) for not only Dentists but also Dental Care Professionals (DCP’s).

The whole subject of Infection Prevention and Control is huge and I can only cover one small part of this in this article. Hopefully you will feel that it has given you food for thought and inspires you to do more reading and research of your own. My book, The Dental Nurses Guide to Infection Control and Decontamination by Quay Books, gives more in-depth information and sources for further study.

The GDC requires DCP’s to complete 10 hours of disinfection and decontamination CPD in every 5 year cycle. This is a small but essential part of the whole subject and is arguably the most important. There can be no effective infection prevention and control without effective and efficient disinfection and decontamination. These two are similar but not the same and the differences must be clear to whoever is performing the task. Confusion could lead to patients being put at risk.

Disinfection has been defined as a process used to reduce the number of micro-organisms, but which does not usually kill or remove all the micro-organisms, rather it reduces them to a level which is not harmful to health.

Decontamination is a term used for the destruction or removal of microbial contamination to render an item safer to handle.


Basic Disinfection Procedures

Disinfection should only be used as a means of decontamination for those items or pieces of equipment which cannot be sterilised by autoclaving. It should never be used as a “quick fix” to save time.

In general this relates to large pieces of equipment such as the dental chair and unit, work surfaces etc. The only small items which should be disinfected are items such as protective glasses, some cheek retractors, some photographic minors etc. The key phrase that drives this is “follow the manufacturers’ instructions”; this also applies to decontamination advice and sterilisation.

No item designated as “Single Use” should ever be disinfected, decontaminated or sterilised and used a second time.


Large items of equipment should be cleaned using an appropriate cleaner as advised by the manufacturer WEB_GroupCICLiquidsAlcoholFreeand then wiped over using a recommended disinfectant. This should be made up to the correct concentration when necessary and applied in the recommended way.

When choosing a suitable disinfectant the bactericidal, virucidal and fungicidal properties should be carefully studied as these are essential for an effective disinfectant. A product which has all these properties will give the best possible spectrum of protection.

For small items, once they have been disinfected, they can be stored in sterilisation pouches to help prevent recontamination. For such items, it may be appropriate to use a similar solution as that used to disinfect items to be sent to the laboratory or for repair. This will entail soaking them in the solution for the recommended time and then rinsing and drying them. For things like protective glasses all that can be done is to wipe them thoroughly using a disinfectant solution or wiping them with an alcohol impregnated wipe.

Whenever handling, mixing or disposing of disinfectant solutions, Personal Protective Equipment must be worn. There should also be a Control of Substances Hazardous to Health (COSHH) risk assessment carried out, documented, updated regularly and kept in the area where the substance is being used. It is also essential that all staff who come into contact with it or use it, are adequately trained in its safe use and storage.



The whole decontamination process is one which renders a contaminated item safe to use on a subsequent patient, by virtue of the fact that all pathogenic micro-organisms have been killed or removed from the item. The process is complete when the item has been sterilised, usually by autoclaving which is the stage when all the pathogens are destroyed. This can only be achieved if the item has been effectively decontaminated before sterilisation.

It should be remembered that although sterilisation will kill or destroy all pathogens it will not necessarily destroy Prions which are not living organisms, but mutant proteins.

The decontamination prior to sterilisation must remove all deposits, blood and saliva. The enzymes in blood and saliva will prohibit the action of the steam against the material of the item, thus giving incomplete sterilisation. Any debris left on the item will not allow penetration of the steam underneath it, so that area will not be sterile.

The first stage in this process is cleaning. This can be achieved by one of two methods:

i) Manual Cleaning

Manual cleaning should be restricted to those large items which cannot be mechanically cleaned i.e. the dental chair and unit etc. It is not recommended for instruments etc. For two main reasons:-

a) Danger of the operator receiving a percutaneous (sharps) injury.

b) Thorough removal of all blood, saliva and debris is very difficult manually.


However it is a fact that not all dental practices have a mechanical cleaning facility, so instruments have to be cleaned manually. This should be carried out in a designated sink which is used for this purpose only and is deep enough so that the instruments can be totally immersed in water during cleaning. Debris should be removed using either a disposable or autoclavable brush or some form of disposable scourer. A brush or scourer should not be used on more than one set of contaminated instruments. If a brush is used, it must be autoclaved after each set of instruments has been cleaned.

After cleaning and before loading into an autoclave, they must be checked for visible cleanliness. If they are not clean then they must be cleaned until they are. If clean, they should be thoroughly rinsed, carefully dried, using disposable cloths and then spread out on an autoclave tray.

Full Personal Protective Equipment (PPE) must be worn to perform this operation.

ii) Mechanical Cleaning

There are two main types of mechanical cleaner, an Ultrasonic Bath or a Washer / Disinfector. Manufacturers’ instructions must be followed for the installation, use and servicing of both types of machine. Instruments decontaminated in either machine, must be sterilised before use. They do not sterilise only decontaminate.


Ultrasonic Baths

These work by using high frequency sound waves to agitate the solution and produce millions of tiny bubbles, which implode against the instrument, forcing the debris, blood or saliva off. They must be subjected to weekly tests as to their efficiency, which must be documented and kept for audit purposes. They also need to be calibrated when first – bought to find the optimum time that instruments should stay in there for.

The solution should be a recognised enzymatic solution which will break down the enzymes left by blood and saliva which would inhibit sterilisation. It is not sufficient to just put washing up liquid into the water.

Instruments must be put into a basket in the bath and not straight onto the floor of the bath to allow circulation of the cleaning fluid. The bath should also have a tight fitting lid which must always be in place when the bath is in use. This is because an aerosol is produced by the bubbles, which is made up of a mixture of cleaning solution and contaminated particles from the instruments.

After removal from the bath, they must be rinsed to remove the enzymatic cleaner and then carefully inspected for cleanliness. If visibly clean then they should be dried and spread out on an autoclave tray and then autoclaved.

As with manual cleaning full PPE must be worn by staff dealing with contaminated instruments and using the ultrasonic bath. There should also be COSHH risk assessments available for the solutions used.

The bath should be emptied and cleaned at least at the end of every session but more often if the water becomes heavily contaminated or obviously dirty. It should be emptied every time it is used to decontaminate heavily blood contaminated items such as forceps, elevators or surgical instruments.


Washer / Disinfectors

These are a relative new innovation for dental surgeries, although they have been used for some time in large purpose built decontamination facilities. They are, basically, sophisticated dish washers. The disadvantages of these machines are – large pieces of equipment, although bench top versions are now available; expensive to buy; time consuming to use; need to have regular maintenance from outside technicians; and need to be plumbed into both the water and waste systems.

There are advantages, these being – give a high level of decontamination; instruments come out dry reducing the risk of percutaneous injury during drying; make the instruments safer to handle; and they decontaminate the lumens inside handpieces etc.

Users must wear full PPE when using the machines and COSHH risk assessments for the solvents used must be available in the area of the machine. All staff using it must be adequately and appropriately trained in its use.

When instruments are removed from the machine they must be checked for cleanliness prior to spreading out on an autoclave tray ready for sterilising.

The mechanical cleaning systems should be the systems of choice but if they are installed, back up systems must be in place to cope with any breakdowns or malfunctions.

The decontamination process is completed by the instruments being sterilised.

Briefly, sterilisation is effected by the action of steam under pressure. This is achieved with a displacement autoclave or a vacuum phase autoclave. The recommendation to Dentists replacing autoclaves is to buy a vacuum phase model as this will ensure the complete sterilisation of all surfaces, including the lumens inside handpieces.

The most commonly used temperature / time cycle is 135°C for a minimum of 3 minutes. Some more delicate instruments need to be sterilised at a lower temperature for a longer time. Again the manufacturer’s instructions should be followed. Instruments should be spaced out on the trays to allow adequate exposure of all surfaces to the steam and the autoclave should not be overloaded.

Autoclaves should be drained at the end of each day and left clean and dry. They are also subject to mandatory checks, daily, weekly, quarterly and yearly, all of which must be fully documented and kept for audit purposes.

Disinfection and decontamination should be carried out in a designated “dirty area” and sterilisation in a designated “clean area”. There must not be any overlapping of the processes carried out in each area or effective sterilisation will not be achieved.

After sterilisation, instruments taken from a displacement autoclave need to be dried and packed in pouches to be stored. They must not be sterilised in pouches, only instruments going through a vacuum phase autoclave can be packed in pouches prior to autoclaving.

It is imperative that sterilised items are stored in clean dry conditions and used in rotation.

This is only a brief overview of a complicated process and should provide the stimulus to dental nurses to learn more and look at their own disinfection and decontamination practices as well as those of other staff.

About the Author

Kathlyn (Kathy) Porter is now retired having been a qualified and registered Dental Nurse for 38 years mainly spent in various guises at Birmingham Dental Hospital. Her title was – Senior Dental Nurse (Decontamination). She was a member of the editorial board of the “Dental Nursing” Journal and also wrote articles for them. She has had a book, entitled “The Dental Nurses Guide to Infection Control and Decontamination”, published in the spring of 2008. Kathy Porter cannot endorse any of the products advertised in this article.


There are some real benefits to using Kemdent’s new PumiceSafe Universal Cleaner


Because there are no specific EU Regulations regarding disinfection within Laboratories, the DLA, in association with the BDA and BDIA, have developed their own series of Fact Sheets designed to enable Laboratories to implement Best Practice for the control of cross infection within the Laboratory.

These Fact Sheets cover various aspects of cross infection control, including the Laboratories responsibilities in a variety of situations, including performing repairs for the General Public and acting as CDTs.

PumiceSafeUniversalCleanerWithin these recommendations they highlight the potential risk of cross infection associated with denture repairs and the use of contaminated pumice slurry between one patient’s prosthesis and another’s.

Within production areas, the DLA Fact Sheet CI01 states that “all work benches, sinks and model trimmers benefit from being wiped down daily with a disinfection solution” and that “as far as practical the Laboratory should be kept as clean as possible”. However, due to the nature of the production work, nobody would be expected to maintain a spotlessly clean working environment. However, there is “no excuse for not cleaning up on a daily basis and in particular making sure dust is removed by vacuuming and wiping down the benches”

With regard to pumice, the DLA Fact Sheet states that “it has been shown that bacteria can survive in dental pumice for extended periods of time.

In a dental laboratory where the polishing lathe is constantly used, it is important that the items polished are free of bacteria when brought into the area. This is particularly important when dealing with items like repairs. If the repaired prosthesis has not been disinfected it may transfer bacteria into the pumice which will then be used on new appliances.

If items are then shipped back to the surgery still contaminated with this pumice it is possible that when the patient is fitted with the appliance, they will be at risk of becoming infected by the bacteria present in the contaminated pumice.

It is therefore important to change the pumice on a regular basis and disinfect the pan holding the pumice before putting fresh pumice into it.

It is strongly advised that the same pumice is not used for new work and repair work. When working on repairs, it is recommended that a small fresh amount of pumice is dispensed and used.

As pumice always produces a contaminated splatter and aerosol, a liquid disinfectant should be used as the mixing medium in pumice.”

PumiceSafeLatheBrushRegarding rag wheels and brushes the same Fact Sheet states

“Always wear a dust/mist-type facemask and eye protection when operating a model trimmer, brush trimmer or rag wheel with pumice.

Rag wheels and brushes should be soaked for ten minutes after use and left to dry overnight.”

As well as advising on pumice, Fact Sheet CI01 also highlights the importance of cleaning work surfaces with an appropriate disinfectant, especially if the Laboratory does not have sufficient space for separate benches for processing incoming and outgoing work.

As a bare minimum all work benches should be wiped down with a suitable disinfectant at the beginning and end of each workday.

Finally the Fact Sheet states “If a Laboratory chooses to provide dentures direct to the public it is essential that a high standard of infection controlled should be practised at all times.” In these circumstances it is the CDT who has taken on the legal responsibility for infection control normally undertaken by the Dentist.


What does this mean for pumice?

First and foremost, the DLA Guidelines say that Laboratories should use a disinfectant solution, not just water, to make up their pumice slurries.



Because, unless it is discarded every day, in a warm Laboratory environment a water-based pumice slurry can quickly start to smell and often even develops a mouldy surface, which is unpleasant to deal with and has to be removed before the underlying pumice can be used.


What causes this mould?

PumiceSafePouringIf the pumice is not regularly discarded it quickly becomes impregnated with microorganism-laden stagnant water, which starts to smell and develop a surface mould of algae. This problem can be exacerbated where denture repairs are concerned, because the worn dentures are often plastered (sic) in bacteria and other microorganisms from the patient’s mouth, unless the very strictest disinfection protocols have been employed. Even then this can be extremely difficult to achieve with 100% success due to the presence of interstitial bacteria etc. Though this risk can be reduced slightly by having two pumice sources, one for new dentures and one for repairs.

Even if Technicians wear face masks, whilst using their pumice slurry, they are still being exposed to the microorganism-laden pumice spray which is neither pleasant nor healthy.
Another potential source of cross infection are the lathe brushes used as part of the polishing process. These are rarely, if ever, disinfected normally, but if soaked in a suitable disinfectant they can be disinfected easily without causing any damage to them. In addition, this will dramatically reduce the risk of burning the acrylic associated with the use of dry lathe brushes.


What is the answer?

If the pumice is not regularly discarded it quickly becomes impregnated with microorganism-laden stagnant water, which starts to smell and develop a surface mould of algae.

Kemdent have introduced PumiceSafe, which is specifically designed to prevent the development of the mould in pumice slurry as well as offering other benefits.

PumiceSafe is an alcohol-free, water-based cleaning solution which can be used in place of the ordinary tap water most Laboratories currently use to make their pumice slurries. It can also be used as work surface cleaner.

Supplied ready-to-use, so there is no need to dilute any concentrated solution, it can simply be dispensed, a few drops at a time, as and when required. Non-foamy, it is used to produce a pleasant smelling microorganism-free pumice slurry and also helps reduce the presence of dust within the Laboratory environment.

PumiceSafeSprayNon-greasy or slimy it is ideal for use with a cloth as a surface cleaner too, where it will help maintain a clean and dust-free environment easily removing light to moderate dirt and other surface debris. PumiceSafe can also be used as a soak for lathe brushes to remove pumice debris. Here it also softens the lathe brushes and as the soak becomes contaminated with debris it changes colour, from pale blue to dark green, providing a clear visible indicator that it is time to change the soak.

Alcohol-free, so that it does not dry out or irritate the Technician’s skin during frequent contact, other benefits associated with PumiceSafe are its pleasant minty fragrance, which helps generate a more pleasant working environment, and its glycerine and emollient content, which help keep the Technician’s hands softer and helps prevent them drying out due to contact with the various irritant chemicals and powders routinely found within Prosthetic Laboratories.

PumiceSafe is supplied in 5 litre refill containers and 500ml spray units for surface applications.


Cost effective

Competitively priced, using PumiceSafe enables Laboratories to use the same pumice for longer before it starts to smell and look unsightly. Consequently it saves time and money compared with traditional pumice/water slurry, which needs replacing at least weekly, if not daily, in heavy duty or warm weather use.

Not only is PumiceSafe nicer to use, but it saves Laboratories money too!

For more information about PumiceSafe Universal Cleaner Click Here

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