Introduction This study was conducted in light of the SARS-CoV-2 pandemic, which brought UK dentistry to a standstill. The market has seen a recent influx of unproven extraoral scavengers (EOSs), which claim to reduce the risk of particulate spread. Aims To investigate the efficacy of a commercially available EOS device on contamination reduction during dental aerosol generating procedures (AGPs). The secondary aim was to investigate differences between open and closed dental operatories. Method Dental procedures were simulated on a dental manikin using citric acid (10%) added to the water lines with universal indicating paper (UIP) placed in strategic locations in the operatory, on the clinician and assistant. Chromatic change related to settling of splatter containing citric acid on the UIP was analysed to calculate percentage intensity of splatter contamination. Results EOSs resulted in 20% reduction in frequency and 75% reduction in mean intensity of contamination of operatory sites. There was a 33% and 76% reduction in mean intensity contamination for clinician and assistant, respectively. Use of rubber dam and four-handed dentistry resulted in further reduction. Discussion This exploratory study demonstrates contamination by splatter in a simulated dental setting. The concern in dentistry regarding aerosol requires further quantitative investigation of smaller particles. Conclusions The routine use of four-handed dentistry and rubber dam should continue where possible to maximise risk mitigation during AGPs. However, on the basis of our findings, the use of an EOS device can further mitigate the magnitude and concentration of splatter.

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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 'very small' (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.

AGPs can be carried out in open bay environments with a minimum of six air changes per hour of mechanical ventilation.Four-handed dentistry with high-volume suction and a saliva ejector are essential mitigating factors during AGPs.

AimTo calculate fallow time (FT) required following dental aerosol generating procedures (AGPs) in both a dental hospital (mechanically ventilated) and primary care (non-mechanically ventilated). Secondary outcomes were to identify spread and persistence of aerosol in open clinics compared to closed surgeries (mechanically ventilated environment), and identify if extra-oral scavenging (EOS) reduces production of aerosol and FT.MethodsIn vitro simulation of fast handpiece (FHP) cavity preparations using a manikin was conducted in a mechanically and non-mechanically ventilated environment using Optical Particle Sizer™ and NanoScan™ at baseline, during the procedure and fallow period.ResultsAGPs carried out in the non-mechanically, non-ventilated environment failed to achieve baseline particle levels after one hour. In contrast, when windows were opened after AGP, there was an immediate reduction in all particle sizes.In mechanically ventilated environments the baseline levels of particles were very low and particle count returned to baseline within 10 minutes following AGP. There was no detectable difference between particles in mechanically ventilated open bays and closed surgeries.The effect of the EOS was greater in non-mechanically ventilated environment on reducing the particle count; additionally, it also reduced the spikes in particle counts in mechanically ventilated environments.ConclusionHigh-efficiency particulate air filtered mechanical ventilation along with mitigating factors (high-volume suction) resulted in reduction of FT (10 minutes). Non-ventilated rooms failed to reach baseline level even after one hour of FT. There was no difference in particle counts in open bay or closed surgeries in mechanically ventilated settings. The use of an EOS device can reduce the particulate spikes during procedures in both mechanical and non-mechanical environments.This study confirms that AGPs are not recommended in dental surgeries where no ventilation is possible. No difference was demonstrated in FT required in open bays and closed surgeries in mechanically ventilated settings.Clinical significanceAGPs should not be carried out in surgeries where ventilation is not possible. Mechanical ventilation for AGPs should be gold standard; where not available or practical then the use of natural ventilation with EOS helps reduce FT. AGPs can be carried out in open bay environment with a minimum of 6 air changes per hour of mechanical ventilation. Four-handed dentistry with high-volume suction and saliva ejector are essential mitigating factors during AGPs.