10 November 2020

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Quantification of the risk of contagion for dental healthcare professionals during the Covid-19 pandemic

Lara Figini

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Providing dental care during infectious disease outbreaks carries inherent risks for dental healthcare professionals (DHPs) due to the splashes and aerosols generated during dental treatments. The HIV / AIDS epidemic in the 1980s caused great anxiety in dental clinic DHPs for fear of the spread of a deadly, blood-borne infectious disease, and accelerated the adoption of universal precautions that emphasized efficient sterilization, hand hygiene and the use of personal protective equipment (PPE) during dental treatments. Basic PPE include: face masks, gloves, gowns, headphones, goggles and face shields.
To date, there are no confirmed cases of COVID-19 transmission or dental care-associated mortality for DHPs and their patients, while many doctors and nurses have fallen victim to COVID-19 worldwide. However, there are undeniable potential risks for disease transmission in dental practices during the COVID-19 pandemic.

Materials and Methods
In a review published on the Journal of Dentistry in July 2020, the authors researched the studies available in the literature and estimated the annual risk for a DHP healthcare professionals (dentists and assistants) of becoming infected by an asymptomatic patient in the dental office consequently become symptomatic and in extreme cases die from COVID-19 infection. 

The authors investigated: 

- 1: the prevalence of asymptomatic patients in the local population;
- 2: the probability that a DHP will be infected by an asymptomatic patient;
- 3: the effectiveness of PPE personal protective equipment;
- 4: the likelihood of becoming symptomatic after being infected with asymptomatic patients;
- 5: the probability of dying from the disease;
- 6: the number of patients seen per day;
- 7: the number of working days per year. 

To understand the potential impact of COVID-19 in dentistry and oral health e assessing the risks for DHP deriving from the disease while providing essential services to society, the authors periodically researched and analyzed all the publications in the literature on the subject through the PubMed and Google Scholar portals using various combinations of keywords.

Results
If dentists and assistants wear the proper DHPs personal safety devices correctly throughout the working time, wearing an N95 face mask, the annualized probability that a DHP will contract COVID-19 infection in a dental office, becomes symptomatic, and dies for infection it is estimated at 1: 13,000 (0.008%). 

Conclusions
The risk of transmission of COVID-19 in dental office is very low due to the effectiveness of PPE and based on the prevalence of asymptomatic patients. The use of face shields by healthcare professionals and having patients perform pre-procedure oral rinses can further reduce the risks. 

Clinical implications
To minimize Covid-19 contagion in dental clinics, DHP healthcare professionals should follow the guidelines on pre-appointment protocols and always and correctly use PPE during dental treatments.

For additional information: Risk for dental healthcare professionals during the COVID-19 global pandemic: an evidence-based assessment