  Recent guidelines by WHO recommend delaying non-essential oral health care
amid COVID-19 pandemic and call for research on aerosol generated during dental
procedures. Thus, this study aims to assess the mechanisms of dental aerosol
dispersion in dental offices and to provide recommendations based on a
quantitative study to minimize infection transmission in dental offices. The
spread and removal of aerosol particles generated from dental procedures in a
dental office are measured near the source and at the corner of the office. We
studied the effects of air purification (on/off), door condition (open/close),
and particle sizes on the temporal concentration distribution of particles. The
results show that in the worst-scenario scenario it takes 95 min for 0.5 um
particles to settle, and that it takes a shorter time for the larger particles.
The indoor air purifier tested expedited the removal time at least 6.3 times
faster than the scenario air purifier off. Airborne particles may be
transported from the source to the rest of the room, even when the particle
concentrations in the generation zone return to the background level. These
results are expected to be valuable to related policy making and technology
development for infection disease control in dental offices and similar built
environments.
