Figure 1

Workflow of the analysis. The documents available in the COVID-19 Open Research Dataset (CORD-19) were filtered using the “Summary page COVID-19 risk factors” and the “Mining COVID-19 scientific paper” notebooks available on Kaggle (https://www.kaggle.com/mlconsult/summary-page-covid-19-risk-factors and https://www.kaggle.com/mobassir/mining-covid-19-scientific-papers, respectively). The text mining classification of the documents was compared to the author's classification of the list based on title, abstract and excerpt. Finally, eight papers in the category “Oral manifestations in patients with COVID-19” were selected after full-text review to extract data.