Despite existing guidelines addressing health care needs, there is a growing confusion concerning the reuse of advanced personal protective equipment (PPE) by dental care providers outside hospital settings. Unlike general medical practitioners, dentists are involved in aerosol generating procedures (AGP) and are exposed to potentially infectious, virus-containing splatter on daily clinical basis [1]. Whilst the COVID-19 pandemic is far from over and its second wave is deemed as unavoidable, the reuse of advanced PPE (FFP2/FFP3 respirators, long-sleeved fluid repellent disposable gowns, enhanced visors and goggles) should be also carefully taken into consideration, according to Public Health England (PHE) [2], especially in situations, when the extreme shortages of PPE might hamper the primary health care [3]. Currently, the accessibility of PPE around the world does not seem to be vastly affected [4], compared to the beginning of COVID-19 outbreak [5].

The reuse of PPE in hospitals seems to be relatively well supported by the recent World Health Organization (WHO), as well as PHE guidelines and recommendation implemented in April this year as emergency contingency planning during the peak of COVID-19, when the supply chain was severely affected by global demands [6]. The United States Food and Drug Administration (FDA) has made the emergency use of the Nova2200 to decontaminate compatible N95 respirators available under an emergency access mechanism called an Emergency Use Authorisation (EUA). The EUA is a supported by the Secretary of Health and Human Service’s (HHS’s) declaration that circumstances exist to justify the emergency use of medical devices due to insufficient supply during the COVID-19 pandemic [7]. The reuse of PPE (apart from gloves) can be justifiably utilised by medical and dental clinical staff, in situations when health care must be delivered promptly without any delay and the PPE resources are lacking. In our opinion in case of patients with COVID-19 negative status, the decision concerning the reuse of advanced PPE for dental treatment should be considered in urgent/emergency procedures, when immediate dental care must be delivered and strict procedures regarding the reuse of PPE are present and monitored. The Centers for Disease Control and Prevention (CDC) has acknowledged that an effective Filtering Facepiece Respirator (FFR) decontamination method must reduce the pathogen burden, not harm the fit or filtration of the FFR, and cause no residual chemical hazard. Ultraviolet germicidal irradiation, vaporous hydrogen peroxide, and moist heat have shown the most promise as potential methods to decontaminate FFR. Also, the number of donnings for an N95 FFR (FFP2) should be no more than five per device [8].

However, these recommendations should not be applied for general, routine dental care and dental interventions that require the use of spray-producing equipment within oral cavity, the main (equally with nasal area) 'portal of entry' for microorganisms invading upper and lower respiratory track, including SARS-2-CoV, especially when PPE resources are widely available. In primary dental care sector (general dental care) the reuse of PPE cannot be justified for any non-AGP or AGP, especially not urgent cases, including non-surgical dental extractions as this would jeopardise the main paradigms of cross-infection control rules. This approach inevitably puts dental care providers at serious risk of contracting airborne diseases and causes potentially serious health problems for treated patients [9]. The unjustified (or economically justified) excessive reuse of PPE appears to be particularly harmful when utilised for AGP in vulnerable operator, and as a result, can lead to further health consequences.

‘By definition', the reuse of PPE in any clinical environment has to be treated as the 'very last resort' , in extremely exceptional circumstances, after a formal risk assessment and consideration of benefits/risk for equally the staff and the patients. The consequences that may adversely affect both operators and patients must be assessed and predicted from the medical and legal perspective. The regulatory bodies raised a noticeable concern, that the increased cost of advanced PPE for independent providers might influence their unreasonable and irrational decision to reuse PPE 'on a regular basis' [10]. This should not be allowed to happen in any clinical scenario.

We urge the decision-makers and professional bodies to support dental sector with up-to-date recommendations, based on robustly reviewed and assessed evidence-based medicine sources.

References [1] Izzetti, R.; Nisi, M.; Gabriele, M.; Graziani, F. COVID-19 Transmission in Dental Practice: Brief Review of Preventive Measures in Italy. J. Dent. Res. 2020, 22034520920580. [2] Considerations for acute personal protective equipment (PPE) shortages https://www.gov.uk/government/publications/wuhan-novel-coronavirus-infec... (accessed Aug 23, 2020). [3] Artenstein, A. W. In Pursuit of PPE. N. Engl. J. Med. 2020, 382 (18), e46. https://doi.org/10.1056/NEJMc2010025. [4] PPE deliveries (England): 17 August to 23 August 2020 https://www.gov.uk/government/statistics/ppe-deliveries-england-17-augus... (accessed Aug 25, 2020). [5] Rimmer, A. Covid-19: Third of Surgeons Do Not Have Adequate PPE, Royal College Warns. BMJ 2020, 369, m1492. https://doi.org/10.1136/bmj.m1492. [6] Rational use of personal protective equipment for coronavirus disease (COVID-19) and considerations during severe shortages https://www.who.int/publications-detail-redirect/rational-use-of-persona...(covid-19)-and-considerations-during-severe-shortages (accessed Aug 23, 2020). [7] Emergency Use Authorization. FDA 2020. [8] CDC. Coronavirus Disease 2019 (COVID-19) https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/index.html (accessed Aug 23, 2020). [9] Mahmood, S. U.; Crimbly, F.; Khan, S.; Choudry, E.; Mehwish, S. Strategies for Rational Use of Personal Protective Equipment (PPE) Among Healthcare Providers During the COVID-19 Crisis. Cureus 12 (5). https://doi.org/10.7759/cureus.8248. [10] Rimmer, A. Covid-19: Experts Question Guidance to Reuse PPE. BMJ 2020, 369.

Competing interests: No competing interests