Aim

To discover the safest and most effective way of removing artefacts from stainless steel dental instruments.

Method

Five methods will be used:

  1. A

    Manual scrubbing wearing normal surgical nitrile gloves using Hospec cleaning solution under warm running water

  2. B

    Manual scrubbing wearing heavy duty rubber gloves using Hospec cleaning solution under warm running water

  3. C

    Soaking in Hospec solution and warm water for ten minutes – no manual cleaning

  4. D

    Soaking in an ultrasonic bath containing warm water for ten minutes – no manual cleaning

  5. E

    Washer/disinfector with the recommended detergent – no manual cleaning.

All of the methods will be tested using a control instrument. Glass ionomer luting cement will be applied to a spatula and allowed to settle and dry for 60 minutes. 2-3 mm thickness of glass ionomer luting cement (GI cement) will be smeared onto each spatula to remove any further variables. I have chosen to use GI cement as it is quite common to find instruments that have residual cement on them. Also, GI cement is safe to use and easily visible. Using contaminated instruments would have been dangerous for the sake of this study and doing so could have made it more difficult to see any residue. The spatulas are all made of stainless steel and are suitable for autoclaving at 134°C for three minutes.

Expected result

I expect to find that manual scrubbing will be the most effective at removing artefacts from the control instrument but that this may also present a risk of sharps injury. I expect this because manual scrubbing has been used as a cleaning method in dentistry for many years.

Theory and background research

Needlestick and sharps injuries account for 17% of accidents to NHS staff and are the second most common cause of injury.1 This equates to approximately 400,000 injuries to NHS staff each year.2 Dental nurses are part of an ‘at risk’ group due to the fact that they clean instruments rather than using single-use instruments. Needlestick injuries carry the potential risk of infecting the victim with blood-borne viruses such at hepatitis B (HBV), hepatitis C (HCV) and HIV among others.1 Dental staff are immunised against HBV and should also be using universal precautions when cleaning instruments. This means that dental nurses should assume that all patients have the potential to be carrying infection which may be unknown or undisclosed; and that they should use the same processes to clean instruments that have been used on any patient. The protocol for handling a sharps injury is to encourage bleeding while rinsing the affected area under clean, running water.2 The wound should then be covered with an appropriate dressing or plaster before being reported to an employer and noted in the accident book. The patient's medical history should be checked and Occupational Health should be contacted so that any tests that are required can be arranged.

HTM 01-05 advises that instruments should be cleaned in the washer/disinfector and then autoclaved; it does not advise manual scrubbing.3 Similar findings can be confirmed by research that has been carried out by Edmunds and Rawlinson4 and in local hospital policies such as Ashford and St Peter's Hospital's Cleaning and Disinfection Policy.5

Results

Methods A-C all used Hospec cleaning solution. Hospec is a pH neutral detergent that is used in nearly all UK NHS hospitals and is recommended to be used prior to ultrasonic or steam sterilisation cleaning (ie an autoclave).6 However, the major limitation of using Hospec is that it turns the warm water cloudy. This impedes vision and make sharps injuries more likely when reaching into the sink.

Method A

The benefit of using normal surgical gloves is that they fit tightly to the nurse's hands and thus allow greater manual dexterity. This is particularly useful when manually cleaning small instruments such as dental burs. The main limitation is that surgical gloves are made of a thin material and so don't offer much protection against sharps injuries. During the manual cleaning, the normal surgical gloves ripped. It took three minutes of constant cleaning with an ordinary brush and a bur brush to remove all of the cement.

Method B

Heavy duty gloves are much thicker than surgical gloves and are more difficult to penetrate with sharp objects. They are recommended for use during manual cleaning but are quite cumbersome. This means that it is difficult to clean small instruments such as burs. It took two minutes of constant cleaning with an ordinary brush and a bur brush to remove all of the cement. The gloves were more cumbersome and the bur brush was dropped on one occasion. However, more force was applied during cleaning due to a feeling of increased confidence in the gloves and less fear of a sharps injury.

Method C

During method C when the instruments were soaked in water and Hospec for ten minutes, the water became cloudy. This meant that the dental nurse had to put their hands into the cloudy water and feel for the instruments due to limited visibility. However, it was easier to remove the top layer of the GI cement after ten minutes of soaking. There were still some of the lower layers that needed to be removed by manual scrubbing which took two minutes.

Method D

HTM 01-05 states that ‘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’.3 The limitation of using an ultrasonic bath is that chemicals are required which need to be maintained and changed frequently. This is another time consuming task that dental nurses are presented with. Also, the ultrasonic bath does not hold many instruments so multiple cycles have to be completed. However, during this investigation, ultrasonic cleaning was the most effective method. A lot of the GI cement was removed after ten minutes of ultrasonic cleaning; the current recommendations suggest six minutes is adequate.7 The remainder was removed manually after 30 seconds of brushing. The ultrasonic bath contained a basket with handles which meant that the dental nurse did not have to make contact with any chemicals.

Method E

Washer/disinfectors are the recommended method of cleaning instruments as stated in HTM 01-05.3 The main limitation is that the initial cost is high, with washer/disinfectors costing in the region of £4,000+ to buy.8 There is also the added cost of regular maintenance. At the moment, washer/disinfectors are advised but could potentially become mandatory in the future which may raise their cost further. Also, a wash/disinfect cycle typically takes just under an hour. The instruments then need to be autoclaved and potentially autoclaved a second time on a wrap cycle. This means that the whole cleaning process can potentially take over two hours to complete. Again, the cost implications are high as the surgery needs to have plenty of instruments available so that they do not run out while the cleaning process is taking place. The GI cement was ‘baked’ onto the spatula after being washed/disinfected. None of the original cement had been removed during this process. The dental nurse tried to manually scrub the GI cement off but after three minutes no progress had been made. The hardened GI cement eventually had to be scraped off using another spatula and re-processed.

Limitations

The general limitations of this study are that it relies on qualitative data. Therefore, it is not statistically viable. It would be difficult to conduct such a study of this nature in a quantitative style without advanced imaging software that could analyse the remaining cement on the instruments and potentially create a comparison. Also, methods A and B rely on the nurse scrubbing the instruments. This process is user dependent and depends on the amount of force the dental nurse is applying during the cleaning procedure.

Recommendations

In response to the limitations discovered in method C, dental nurses could instead place all of the dirty instruments into a metal mesh basket which has prominent handles. This basket could then be lowered into the cloudy water while leaving the handles exposed. The basket containing the instruments could then be safely lifted out of the water.

It may also be possible to manufacture a heavy duty glove that is reinforced while still being a good fit. This would provide protection against sharp instruments but would allow greater manual dexterity to clean small instruments.

Another potential resolution would be to manufacture a cleaning solution that does not go cloudy when in contact with warm water. It would have to offer the same level of cleaning and contain similar properties, but would make it safer and easier to see any sharp instruments that are soaking in the solution.