Letters to the Editor

The COVID-19 pandemic has caused substantial disruptions to dental services globally. In the United Kingdom, National Health Service (NHS) dentistry was reduced to telephone consultations with Urgent Dental Care Centres established to deliver emergency dentistry, when deemed necessary, based on a national triaging system. Following lifting of lockdown restrictions, numerous countries released guidance for re-opening and re-structuring dental services to mitigate the risk of SARS-CoV-2 transmission.¹ Such risks are of concern in dental clinics due to the high volume of patients, close physical proximity of dental professionals to patients, and aerosol generating procedures (AGPs).

SARS-CoV-2 has high affinity to angiotensin-converting enzyme 2, distributed throughout the respiratory tract and present in the oral mucosa. The virus has been isolated in saliva and in the pharynx,² hence dental AGPs are stratified as high-risk procedures. The current evidence shows that SARSCoV-2 can remain viable in an aerosol for up to three hours.³ Therefore, a ‘fallow’ period is required for the aerosol to settle after an AGP, and is necessary to prevent infection transmission, but limits the number of patients that can be seen. However, there is considerable heterogeneity in the interpretation of the limited available evidence with respect to risk mitigation strategies (eg the use of rubber dam, high volume aspiration, room ventilation, etc), with countries issuing guidance of different fallow times (ranging from 2–180 minutes)¹ to their dental workforce. There are substantial challenges in meeting population oral health needs if dental services are limited by a fallow period and, in many instances, dental clinics may become financially unviable to maintain. The risk of live SARS-CoV-2 remaining suspended in the air should not be underestimated. Nevertheless, evidence-based consensus is required on ventilation parameters and the most effective risk reduction strategies to enable safe resumption of dental care.