Best Practice cross infection control procedures  - you'd expect nothing less of us. Sadly, attitudes within the profession vary about cross infection control. We know where we stand and we believe our patients feel the same.

As a practice we've always insisted on excellent anti cross-infection procedures. But it's been interesting to watch how the concepts of sterilisation have changed over the years, culminating in a Government document under the grand title of Health Technical Memorandum 01-05 (HTM01-05). This laid out minimum requirements for cross-infection control called 'essential requirements' which had to be in place at the start of January 2011. Should 'essential requirements' should be titled 'bare minimum'?Bacteria

In over 24 years we've existed as a practice we've always strived for a higher level. For instance, one of the changes is the push to use machines called washer disinfectors to wash instruments before they're sterilised. They're basically a reprogrammed dishwasher that costs £6000 instead of £400 and costs a pound every time we run a cycle. And they're running all day, so don't even ask about the costs in a year. We've been using washer disinfectors so long that we've already worn out five machines and we took delivery of two brand new machines in mid 2011! We simultaneously took delivery of two large capacity vacuum autoclaves allowing us to be at the cutting edge of digital monitoring of all our processes. This represents an investment of nearly £40,000 in plant to take us through the next five years. Part of this contract is maintenance and vaildation of equipment, so we know and you KNOW the kit runs properly.

We'd refitted our sterilisation room in 2008, in anticipation of HTM01-05, but as is always the case, the goalposts were moved and we then refitted again in 2010 to create two separate, "clean" and "dirty" rooms. To be honest, the difficulty wasn't just the creation of a second sterilising room, it was the evolution of systems of work. Continuously developing our procedures has produced systems rarely seen outside the best hospital set ups and running them every day makes it all appear very easy.

(Oct 2015 - 33rd rewrite of our cross infection policy completed!)

Sterilisation has to be as good as it gets - no compromise. The concept is one of "universal precautions". Anyone who walks through the door could be carrying Hepatitis B or C, or HIV or MRSA, and they may be blissfully unaware! They often don't know they have infection. You don't know who they are, and often neither do we. So the concept is to imagine everyone has everything! If it's there it needs to be cleaned up and killed - 100% certain.

And this is how we do it!Dirty box

Our number coded instruments are transported from the surgeries to the 'dirty room' in sealed boxes containing a specialist disinfectant to keep them moist.

Instrument trays are stripped and disposables are segregated into types using heavy duty gloves as part of Personal Protective Equipment, for disposal before collection by our certificated disposal contractors. 

Handpieces (drills) are processed using an automatic Scican, compressed air oiler to clean and lubricate them.

Instruments are then processed using a washer disinfector. These two machines thoroughly clean instruments before they are sterilised. Mad Cow disease, BSE, vCJD - call it what you will - is caused by something called a prion. Prions aren't alive like a bacterium or a virus, so they can't actually be killed. The idea of a washer disinfector is to thoroughly wash instruments to remove prions before they are sterilised. If you think about it, an instrument that isn't properly clean will never be properly sterilised.

We consciously run two washer disinfectors, partly to make the working day easier, and partly so that we have a fail safe situation in case of machine failure - and they DO fail! The small white boxes sitting on top of the machines are digital data loggers. These record all the working parameters of the machines so that we can monitor their work. All our digital data is uploaded to our computer system for storage for the future and then backed up to a remote secure server in case it were ever to be needed in the future.

Inspection under magnification and daylight lighting follows and the results logged as evidence.Daylight magnifier inspection

If an instrument fails, it is reprocessed by hand using disposable brushes under water in our scrubbing sink and then rinsed in the separate rinsing sink, prior to reprocessing by washer disinfector and re-inspection.










In addition to daily checking, our washer disinfection process is monitored weekly. We use two methods, the idea again being to create a fail-safe setup.

Protein Residue testing, by swabbing processed instruments and then incubating to indicate whether the instruments are microscopically clean. We photograph the results as evidence of our procedures and store them for the future.

Residual protein test

We also use Wash Check tests, which are placed in with the loads to check if the machine can wash away the red spots on the test strips, These are then stored for the future. These tests can be done quarterly but we do them weekly.


The instruments are then sterilised to kill any bacteria, viruses and spores using high pressure steam in a machine called an autoclave -  every instrument is bagged prior to sterilisation by vacuum autoclave. The vacuum sucks out the air so that there are no pockets that the steam can't get to. Bagging of all our instruments ensures the instruments arrive chairside completely sterile.


The two machines with grey circular doors are our autoclaves. They're at the cutting edge of HTM01-05 and they're much larger than a standard autoclave so they're large enough to take a dental implant kit with ease.


Note the use by dates for instruments - these changed with the latest version of HTM01-05 in 2013. We're up to a year for all our bagged instruments now, much more common sense than the previous requirements that were numbers just plucked out of the air.

Every cycle is documented automatically in intimate detail and digitally logged. These logs are then documented into the paper log book sitting on top of each machine. Both the autoclave data logs and instruments are then marked with labels to indicate which autoclave was used, the cycle number, sterilisation date and use by date. Our instrument trays are engraved on all four sides with a code number which is transferred to the patient notes, the same goes for our handpieces (drills), so we can trace each use of the instruments and the route they took through the system.





We use supermarket labelling guns with peelable labels on each pack. So the label can be detached and transferred to the patient notes.  This label is (from bottom upwards) - cycle number 937 on autoclave number 2. The date sterilised was 15th March 2012, Use before date is 15th May 2012. The handwritten notes indicate that this is tray number T53, which is an examination tray. Our two autoclaves have different colour labels to allow rapid identification.

Use by dates for instruments are now defined at a year by HTM01-05, so the picture below needs an update. We choose to bag ALL of our instruments.


Our autoclaves are subject to three different types of automatic tests, so we know they're running optimally. If they don't work properly, they automatically abort. 

Our autoclaves are tested daily before use to ensure safe working. The essence of the test is to make sure high pressure steam can get into every detail of the instruments. This coil of tubing, called a Helix Device is loaded with a testing strip at the very far end of the tube and the steam has to find its way all the way down to reach it. When a test is successful, the strips change to purple from yellow. (Helix devices are specific to each machine, so if you're buying check with the manufacturer of the autoclave which one to buy).

Helix test for vacuum autoclave

We then store our sterile instruments sealed in boxes within specific storage in the clean side of our decontamination suite.

Every box is labelled, as are the cupboard doors. Otherwise you'd never find anything!

We use a system of rotation and checking to make sure instruments are used before their use by date. Seldom used instruments are re-sterilised if they get to a week before their use by date. The whiteboard to the right of the room is used to track our use by dates and rotation schedule.


This is part of our clean room instrument storage. From here instruments are then transported to the surgeries using "clean" boxes. Clean box for transport to surgery

At the point of use, the label is transferred from instrument pack to the patient's notes and the code numbers of instruments recorded.

17th February 2012.  Legionella in dental unit water lines - an elderly lady in Italy has sadly died from Legionella that has been traced to DUWLs in the dental practice she visited. It's the first legionella case I've been able to trace from a dentist. Now the good news - our water supply used in our chairs is softened, five stage filtered then treated with ultravoilet light - and THEN we treat it with something called Alpron to make sure bugs don't grow in the water. AND THEN - we regularly test our water supplies to our dental chairs using dip slides covered in a nutrient medium. These are incubated for a week and if there's any contamination, red spots appear on the medium. Here's some of ours after 7 days.

Click on this link to how it COULD have looked!

Some things just can't be sterilised because they have places that can't be cleaned well. If that's the case we use disposables. They're bad for the environment, but some things you just can't compromise on. Here's a selection of the less obvious items we don't even try to resterilise. Needles, local anaesthetic cartridges, masks, gloves, rinse cups are taken as expected.

Root canal instruments (at £30+ a set!)

Suction tubing tips

Three in One tips - the bit that is used to squirt air and water.

Dappens dishes - used as small containers for polishing paste and surgery materials

Polishing cups and brushes for polishing teeth.

Applicator brushes for materials.

Covers for items like x-ray machines

Bibs - yes, bibs! 

and so on ....

But how do we make sure everything else is clean?

Subtle things like painting our walls and paintwork with silver ion, antibacterial paint. It kills 99.8% of bacteria in 18 hours - and the effect doesn't wash off. And it's not easy to see in the photographs but our decontamination room lighting is hermetically sealed - how many dead flies have you seen in overhead lights?

And how about doorhandles? How potentially horrible are doorhandles? No matter now many times a handle is wiped all you need is the person before you to be infective and you've got it as well. So how about anticontamination door handles?  We've just bought in a funky new type of handle for some of our doors. It's operated with the forearm.

Hand hygiene is critical - possibly the most important link in the chain. All our hand wash sinks and soap and gel dispensers are either knee operated or infra red, so that they don't need to be touched. Our sinks are modified to remove overflows - there's a theoretical bacterial risk from sink overflows, so we've eliminated them. Handwash audit, UV testing

To check handwashing technique we use ultraviolet sensitive gels to monitor staff performance. Here's a before and after -

Handwashing check, UV testing

The gel is applied before washing, and then using the approved World Health Organisation handwash technique, should all have gone after washing. The UV light points out any bits that are missed.


We use the same UV tests for random spot checks of cleaning - a squirt of UV material on a surface (without the person cleaning knowing it's there) and check it later! Sneaky!

In NHS hospitals a colour coding system is used to segregate cleaning mops, cloths and so on to make sure that nasties aren't transferred from, say a toilet to a surgical area. The problem is that the system isn't compatible with dentistry. Being the type I am I phoned the National Patient Safety Agency and talked to the man who wrote it. He agreed that it wasn't fit for our purpose for dentistry and said he'd actually rewritten it for us BUT, because of funding cutbacks nobody had publicised it! He asked me if I could distribute it! So here is the NHS cleaning colour coding system poster as a download. We've made it easier for staff to get it right by labelling every door with a small notice saying things like "Waiting Area Blue" or "Toilet Red".

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© Hesslewood Lodge Dental Practice 16/11/15