Quantitative particle analysis of particulate matter release during orthodontic procedures: A pilot study.

Introduction: Transmission of SARS-Cov-2 through aerosol has been implicated particularly in the presence of highly concentrated aerosols in enclosed environments. It is accepted that aerosols are produced during a range of dental procedures, posing potential risks to both dental practitioners and patients. There has been little agreement concerning aerosol transmission associated with orthodontics and associated mitigation. Methods: Orthodontic procedures were simulated in a closed side-surgery using a dental manikin on an acrylic model using composite-based adhesive. Adhesive removal representing debonding was undertaken using a 1:1 contra-angle handpiece and fast hand-piece with variation in air and water flow. The removal of acid etch was also simulated with use of combined 3-in-1 air water syringe to remove etch. An optical particle scanner and a spectrometer particle scanner were both to assess particulate matter ranging from 9very small9 (0.08 - 0.26 um) to large (2.7 - 10 um). Results: Standard debonding procedure (involving air but no water) was associated with clear increase in the very small and small (0.26 - 0.9 um) particles, but only for a short period with no significant increases for other sizes. Debonding procedures without air appeared to produce similar levels of aerosol to standard debonding. Debonding in association with water tended to produce large increase in aerosol levels, producing particles of all sizes throughout the experiment. The use of water and a fast hand-piece led to the most significant increase in particles. Combined use of the 3-in-1 air water syringe did not result in any detectable increase in the aerosol levels. Conclusions: Particulate matter was released during orthodontic debonding, although the concentration and volume was markedly less than that associated with the use of a fast hand-piece. No increase in particulates was associated with prolonged use of a 3-in-1 air-water syringe. Particulate levels reduced to baseline levels over a short period (approx. 5 minutes). Further research within alternative, open environments and without air exchange systems is required.