Sources of SARS-CoV-2 and Other Microorganisms in Dental Aerosols

Abstract

On March 16, 2020, 198,000 dentists in the United States closed their doors to patients, fueled by concerns that aerosols generated during dental procedures are potential vehicles for transmission of respiratory pathogens through saliva. Our knowledge of these aerosol constituents is sparse and gleaned from case reports and poorly controlled studies. Therefore, we tracked the origins of microbiota in aerosols generated during ultrasonic scaling, implant osteotomy, and restorative procedures by combining reverse transcriptase quantitative polymerase chain reaction (to identify and quantify SARS-CoV-2) and 16S sequencing (to characterize the entire microbiome) with fine-scale enumeration and source tracking. Linear discriminant analysis of Bray-Curtis dissimilarity distances revealed significant class separation between the salivary microbiome and aerosol microbiota deposited on the operator, patient, assistant, or the environment ( P < 0.01, analysis of similarities). We also discovered that 78% of the microbiota in condensate could be traced to the dental irrigant, while saliva contributed to a median of 0% of aerosol microbiota. We also identified low copy numbers of SARS-CoV-2 virus in the saliva of several asymptomatic patients but none in aerosols generated from these patients. Together, the bacterial and viral data encourage us to conclude that when infection control measures are used, such as preoperative mouth rinses and intraoral high-volume evacuation, dental treatment is not a factor in increasing the risk for transmission of SARS-CoV-2 in asymptomatic patients and that standard infection control practices are sufficiently capable of protecting personnel and patients from exposure to potential pathogens. This information is of immediate urgency, not only for safe resumption of dental treatment during the ongoing COVID-19 pandemic, but also to inform evidence-based selection of personal protection equipment and infection control practices at a time when resources are stretched and personal protection equipment needs to be prioritized.

The New Normalcy in Dentistry after the COVID-19 Pandemic: An Italian Cross-Sectional Survey

“…New methods, such as vaporized hydrogen peroxide and ultraviolet irradiation, have been proposed to decontaminate FFP2 masks [40], although promising, the evidence of their effectiveness remains limited [41]. Furthermore, there has been encouraging evidence on the actual risk of respiratory pathogens during aerosol-generating procedures [42]. Saliva may be not considered a potential source of disease transmission during the aerosol-generating procedures, and a high-volume suction capacity air volume of 150 mm Hg or 325 L/min may be sufficient to eliminate viral contamination of the surrounding environment [42,43].…”

Impact of the Coronavirus on Providing Oral Health Care in the Netherlands

“…Increased transmission in oral health care settings cannot be ruled out 11 . Viral particles can be detected in both saliva 12 and gingival crevicular fluid (GCF) 13 .…”

Experience of patients diagnosed as asymptomatic COVID-19 after dental treatment

“…In a recent case report, even in the presence of SARS-CoV-2 from a throat swab, SARS-CoV-2 RNA was not detected from the oral mucosal tissue; therefore, the true risk of COVID-19 infection from oral tissues cannot be confirmed [13]. A recent paper on the origin of microbes of aerosol that occurred during dental treatment showed that SARS-CoV-2 was detected in the saliva of asymptomatic COVID-19 patients, but not in the aerosol [14]. However, it is needed to be emphasized that saliva is known to contain SARS-CoV-2 RNA and the oral cavity is regarded as the main infection transmission route [15].…”