Alison Edisbury explores ways hygienists can reduce the production of aerosols once dental practices start reopening again.
Like many of my colleagues I have been contemplating when a return to dentistry may occur. As well as what our ‘new normal’ will look like. You only need to take a quick glance at social media to see the concerns within our profession. There’s currently a lot of speculation surrounding changes to the way we might perform routine dentistry going forward.
As a profession we have strict cross-infection control procedures that have long been in place. The use of universal precautions has meant that we follow the same protocol for each and every patient. We take the assumption that all patients have an infectious disease that could spread through aerosol generating procedures (AGPs).
Dental professionals are considered at increased risk of COVID-19 infection. This is due to face-to-face communication, and the exposure to saliva, blood and other bodily fluids.
Life after lockdown
Prior to lockdown, we were adopting extra measures to prevent the transmission of COVID-19. These included screening patients to assess their risk, reinforcing the practise of good hand hygiene and adopting social distancing measures in the practice reception/waiting room.
As a dental hygienist, I spend the majority of my day performing AGPs via ultrasonic scaling and air polishing. However, in the weeks running up to lockdown, I had resorted to hand-scaling only. We know this is not the best method in the treatment of periodontal disease.
We will need to take guidance from a UK regulatory body about any further changes. There is obvious concern regarding how AGPs could spread COVID-19. We may treat patients who pass the screening, but are unaware that they are carrying the virus.
Aerosols are particles less than 50 micrometres in diameter. They are small enough to stay airborne for an extended period before settling on surfaces, or entering the respiratory tract. Aerosols are likely to contain bacteria, viruses, blood, and saliva, as well as sub gingival plaque. Following the completion of ultrasonic scaling, the arms, chest and inner surface of the face mask of the operator have the most contamination, with the aerosol cloud remaining in the air for up to 30 minutes after treatment.
To minimise the risk of infection, we are almost certainly going to have to adopt numerous precautions. Firstly, additional personal protective equipment (PPE) will likely be essential. This might include well-fitted masks, gloves and safety glasses, and possibly visors, scrub caps and disposable gowns. We await guidance from the regulatory body/UK government, about the supply of these items. Secondly, it has also been recommended that patients should use a preprocedural mouth rinse that contains oxidative agents such as 1% hydrogen peroxide or 0.2% povidone. COVID-19 is vulnerable to oxidation. Thirdly, we should employ methods of reducing the aerosol generated during treatments. One way of doing this would be to install an air purification system; another would be to ensure high volume excavation. We would use these measures when undertaking treatments including ultrasonic scaling and air polishing, where we cannot use a rubber dam.
Dental forums discuss air purification systems extensively. These units can quickly and effectively dilute the aerosol in the dental surgery, providing a safer working environment. However, there are currently no guidelines for the design of air purifiers in dental clinics and few published studies. At this time, when most practices are facing huge financial pressures, investing in air purification systems may not be feasible.
High volume evacuation
Efficient HVE is a much more cost-effective method, which can reduce aerosol by more than 90%. Saliva ejectors are low-volume and are not effective in reducing the aerosol cloud. HVE should have a large bore tip with a diameter of 8mm or more and remove a large volume of air.
In my experience a dental assistant can further improve the effectiveness of HVE during ultrasonic scaling and air polishing. It enables the hygienist to focus on the application of the instrument. Whilst the assistant can focus on removing the water, eliminating spray, and reducing the aerosol cloud.
Prior to lockdown I was trialling the Lunos air polishing system from Durr Dental with its prophylaxis cannula. The stand-out feature of this cannula is the protective shield, which the user can rotate. My patients, my assistant and I have all noticed how it is much more effective in reducing the aerosol. The cannula features a unique modified tip. This rotates through 360 degrees offering controlled and precise positioning. Hence aspiration at the source of aerosol production, ie in the mouth.
Not only does this improve our working environment providing greater visibility, but it also increases patient comfort during treatment, whilst ensuring we achieve HVE and minimise extra oral aerosol. Whilst I believe that every hygienist should have dedicated nursing support, again, the financial implications will dictate how soon we can implement this when we return to work. The Durr Dental prophylaxis cannula is an ideal alternative for those working alone, who may otherwise rely on the use of a saliva ejector.
COVID-19 will increase anxiety for both the patient and the dental team, especially with procedures such as ultrasonic scaling and air polishing, due to the production of a visible aerosol cloud. It is therefore vital that we continue to use the robust cross-infection control measures we have developed in dentistry, as well as adopting extra measures to put our patients, our teams, and ourselves at ease.
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