Spray mist and aerosol control in dental room air – summary of current evidence

Introduction: An evidence-based, balanced discussion of the facts regarding the reduction of infection risk during the SARS-CoV-2 pandemic by aerosol-controlling measures in dental practice has not yet been fully conducted. Therefore, the current state of knowledge on spray mist and aerosol control in dental offices will be reported in order to present conclusions on risk reduction of aerogen-transmitted infectious diseases in the dental practices. Methods: Results of studies directly related to spray mist and aerosol control in a dental office, as well as recommendations from publications including national position statements and guidelines for dentistry, are discussed in a narrative format. Results: Decision-making at the onset of the SARS-CoV-2 pandemic was hampered by the limited evidence base, but could be improved as the pandemic duration progressed by publishing more studies about spray mist and indoor aerosol control. Study results on the routine use of dental suction systems (intraoral) can be used to specify limits to their effectiveness in aerosol reduction. Similarly, findings on ubiquitously available natural room ventilation shows very high air exchange per hour (ACH) of up to 40 with continuous cross-ventilation under optimal room geometry with opposing windows, whereas only a limited additional effect can be expected for decentralized mobile air cleaning (DMAC) devices in reducing smaller aerosol particles in the treatment room. Discussion: For optimized infection protection in dentistry, in addition to natural room ventilation and compliance with all known hygiene guidelines, the use of intraoral suction (high-volume evacuator (HVE) with a suction volume > 250 l/min) using a sufficiently large suction cannula (opening ≥ 10 mm), positioned close to the aerosol-generating treatment field, is mandatory. From a clinical point of view, supplementary DMAC devices provide a negligible additional reduction effect during aerosol-generating activities. Room air exchange by natural room ventilation in combination with HVE systems shows a high efficiency and continues to be the standard procedure in dental practices. Future studies must clarify whether DMAC devices with ACH ≥ 6 can be a supplement in exceptional situations with a high risk of infection, for example, when no intraoral suction is used or protective/hygiene measures can only be observed to a limited extent. Conclusion: Established hygiene concepts and protective measures, including room ventilation with fresh air, have proven to be sufficiently effective in dental practice even during the SARS-CoV-2 pandemic. Keywords: SARSCoV-2, aerogene-transmitted infectious diseases, aerosol, guidelines