Estimating COVID-19 prevalence and infection control practices among US dentists

they reported that they would be willing to participate in a study on symptoms, testing, or diagnosis of COVID-19. In total, 5,479 dentists received an invitation to participate in the survey on June 8, 2020; a reminder invitation e-mail was sent June 11, 2020.

The survey also asked respondents to identify symptoms experienced in the past month (defined as since May 8, 2020), health conditions associated with COVID-19 severity,

and dental and nondental activities in the past month.

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Respondents who reported providing oral health care in the past month were asked about infection prevention or control procedures in their primary dental practice. Respondents indicated which personal protective equipment (PPE) they used when treating patients in the past month and whether they used it sometimes or always. The CDC interim guidance document was used to categorize PPE use,

and respondents were categorized as following PPE guidance for AGDP if, in addition to basic clinical PPE of gloves and protective clothing, they “always” wore an N95 or similarly protective respirator (also called an “N95 mask”) with eye protection, or the highest level of surgical face mask available with a full-face shield. Dentists who performed no AGDP were categorized as following PPE guidance if they “always” wore gloves, protective clothing, a surgical mask, and eye protection. Occupational Safety and Health Administration guidance was used to categorize the risk of transmitting SARS-CoV-2 to dental providers or patients.

Finally, respondents who reported wearing respirators or masks were asked how often they changed them. The ADA Institutional Review Board approved the research protocol and survey, which are registered at ClinicalTrials.gov (NCT04423770).

and China (1.1%),

but lower than the rate in Seattle, Washington (5.3%).

Furthermore, in our sample, 3.7% of nasal or throat swabs tested positive, which is lower than the 10.3% positivity in respiratory specimens from the broader US population from March 1, 2020 through June 13, 2020.

This might reflect the higher socioeconomic status of many dentists and their subsequent ability to use social distancing and mitigate viral exposure.

As of June 29, 2020, patient volume in dental practices nationwide was estimated to be 70% of pre–COVID-19 levels, and it has been increasing steadily.

Use of disposable products for PPE and infection control might increase if patient volume increases, which could result in scarcity or alteration of practices within dental offices based on availability. In addition, changes in local and regional ordinances and infection rates might also alter practices within dental offices moving forward, particularly as COVID-19 cases resurge in many states.

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but nonrespondents might differ from respondents, which can reduce the validity and generalizability of these results. The survey sample might also be subject to selection bias, leading to an underestimation of COVID-19 prevalence or severity because dentists who have died or been hospitalized with COVID-19, for example, cannot or might be less likely to participate. Due to the limited availability of COVID-19 tests in the United States,

it is possible respondents had limited access to COVID-19 testing and might have had undiagnosed infections. Furthermore, these findings are only as accurate as the COVID-19 tests and diagnoses themselves, which can be subject to false-negative and false-positive results.

There might be recall bias in the questions that asked about activities and symptoms in the past month. It is likely that respondents reported higher levels of social distancing and infection prevention and control compliance due to social desirability bias and unrecognized lapses in PPE usage. These cross-sectional data were also limited in that the timing of known SARS-CoV-2 infections in this survey sample precluded testing for associations with symptoms, activities, or infection prevention and control efforts.

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Subsequently, the number of dental patients seen and procedures conducted in the United States dropped.

In this survey sample, 75.0% (n = 15) of dentists with presumed or confirmed COVID-19 tested positive in March or April, when 95% of US dental practices were closed or provided only emergency oral health care.

Subsequent surveys sent to the cohort described in our study will continue to collect COVID-19 test results, symptoms, activities, and infection prevention and control efforts in dental practices. Future research in this cohort might therefore be able to estimate COVID-19 incidence, as well as associations with dental activities and infection prevention or control efforts.