COVID-19 is spread via respiratory droplets when an infected person sneezes or coughs, or by aerosol spread (within 1m) of another person, or via contact routes, where the droplets land on a surface and are transferred by touch. Airborne transmission may occur if the droplets are aerosolised when certain procedures are performed, such as the use of high-speed drills, ultrasonic scalers, triplex syringes, particle beams and hard tissue lasers.
 
A Level 2 or 3 Surgical Mask, or P2/N95 respirator may be worn when caring for patients on droplet precautions (for example, undertaking urgent procedures on medium risk patients with no aerosols being generated).
 

Masks protect the mucous membranes of the nose and mouth, and they protect the skin of the face and neck from splashes of material. This is why masks rated for healthcare require splash protection, according to the level of risk of splashes of fluid. Masks must be worn wherever there is the possibility of splashing, splattering, or spraying of blood, saliva, or body substances, or where there's a probability of inhalation of aerosols with the potential for transmission of airborne pathogens. Masks also prevents contamination of the working area with the operator’s respiratory or nasal secretions and organisms.

This depends on the COVID-19 risk of the patient and the prescribed treatment. If the patient has a low risk of having COVID-19, and the procedure does not involve aerosol or aerosol is minimised with the use of rubber dam and high volume suction, then standard universal precautions plus the additional COVID-19 measures (pre-operative rinse and additional environmental cleaning) are sufficient. 

While it might seem like the obvious solution, according to the Dental Board of Australia and manufacturers of these products, masks are typically labelled as a single-use item and cannot be reprocessed.

The filtration abilities of a surgical mask start to deteriorate after around 20 minutes of continuous use as a result of moisture on the inner and outer surfaces of the mask. It is not necessary to change it after this time if you are in the middle of a procedure which goes for a longer period. However, masks should be changed between patients.

Steam sterilising renders the mask ineffective by altering the charge on the microfibers that are responsible for particle filtration, causes degradation of the mask straps, renders the splash protection useless, and causes parts of the mask to disintegrate or melt, and release some toxic vapours.

Yes, but you must check that they are suitable for health care use and they must be fitted correctly. You will find information on how to fit check a P2/N95 mask here. P2/N95 masks will not seal effectively unless you are clean shaven.

The terms P2/N95 respirator are used interchangeably to cover both US and European standards. They have the same level of protection for particles in the same size range as most viruses (0-.1-0.3 microns). N95 respirators are used for oil free aerosols where P2 respirators are tested with paraffin oil. European standards refer to filtering face piece (FFP) masks and in that scheme, FFP2 matches with N95.

A correctly fitted P2/N95 respirator will block 99% of total viral influenza particles, but effectiveness drops to 66% if poorly fitted (e.g. not matched to the size and shape of the face). A poorly fitted P2/N95 mask performs little better than a poor fitting surgical mask.

Fit checking is the appropriate minimum standard at the point of use for healthcare workers using P2/N95 respirators. Fit checking is required when using a P2/N95 respirator to treat low risk and medium risk patients. Fit checking is performed by the practitioner every time they put on a P2/N95 respirator to ensure it is fitted correctly, and air is not leaking around the perimeter of the mask. A good seal must be achieved over the bridge of the nose and mouth, with no gaps between the respirator and face. Facial hair (beards and stubble) prevent an air-tight seal being obtained. No clinical activity should be commenced until a satisfactory fit has been achieved with the respirator.
 
The following Queensland Health PowerPoint presentation describes a fit-check procedure for a P2/N95 respirator:
https://www.health.qld.gov.au/clinical-practice/guidelines-procedures/diseases-infection/infection-prevention/transmission-precautions/p2n95-mask
 
Fit-testing is carried out to select the ideal respirator for each individual. A risk-management approach should be applied to ensure that staff working in areas with a significant risk of exposure are professionally fit -tested and are trained in how to correctly use the respirator including performing a fit-check at the time of use. Fit testing is conducted by an appropriately trained technician, using a qualitative or quantitative method to evaluate the fit of a specific make, model and size of respirator on an individual. The test verifies that the mask has achieved an adequate seal and that this seal is being maintained in reasonable challenge conditions such as when deep breathing, talking, when the head moves or when exertion occurs. No high-risk patient in the context of COVID-19 should be treated without a properly fit-tested respirator.
 

The answer is NO. P2/N95 surgical respirators are a one-time-use item. There is no acceptable or effective way to reprocesses these. The manufacturers do not recommend or support attempts to sanitize, disinfect, or sterilize them.

All methods that have been tried suffer from at least one of the following four problems: 

• they are not effective against the COVID-19 virus;
• they damage the respirator’s filtration;
• They affect the respirator’s fit to the face; 
• they create safety problems for the person wearing the respirator (e.g. off-gassing of chemicals into the breathing zone). 

Face shields and a visors do not protect against aerosols as they have no filtration and do not meet the Standard required by the regulator, so they are not a suitable replacement for a surgical mask or a surgical repirator. They can be worn in conjunction with a surgical mask or respirator for eye protection. A surgical mask may also have a visor already attached to it. 

If you’re unable to practice due to insufficient PPE, contact the ADA team on 02 8815 3333 or send an email to [email protected] and we’ll do everything we can to help you.