Evidence-based strategies to reduce contamination from aerosolised microbes in dental practice environment.

Cohort selection The aim was to evaluate interventions to minimise microbial contamination from aerosol generating procedures in the dental office. Seven electronic databases were searched using key words such as 'aerosols', 'droplets', 'spatter', 'microbial loads' etc to identify relevant randomised controlled trials and prospective non-randomised clinical trials until 6 April 2020.Data sources PubMed; Scopus; Cochrane Central Register of Controlled Trials; Cochrane Database of Systematic Reviews; Open Grey; ClinicalTrials.gov; National Research Register; and hand searches.Data analysis Eligible studies were analysed for effectiveness of various interventions on the microbial counts in the aerosols generated in the dental office using predefined criteria. Data were analysed for assessment of quality of evidence and confidence in the estimated effect, risk of bias and other analyses using Stata 15.1 software. PRISMA guidelines extension for network meta-analysis were followed for reporting.Results Initial search identified 266 studies, of which 35 were evaluated for full text. Finally, 29 studies fulfilled the eligibility criteria for qualitative synthesis. The majority of the included studies were published in the last decade, and 21 out of the 29 studies were randomised controlled trials. However, based on comparable procedural settings (study design, study populations, interventions and outcome measures), only 11 were eligible for contribution to the network meta-analysis. The setting of all interventions was ultrasonic scaling of adult patients in a clinical dental practice environment, and involved 16 direct and 29 indirect comparisons. A multivariate meta-analysis showed pre-procedural mouth rinse with tempered chlorhexidine 0.2% at 47°C was most effective in reducing post-procedural bacterial load compared to the control. A mean difference of -0.92 (95% CI -15.4 to -0.29) in log10 colony-forming units was observed in air samples within 90 cm of the dental unit.Conclusions Notwithstanding the limitations of this network meta-analysis, pre-procedural mouth rinse with tempered chlorhexidine appears to be most effective in reducing bacterial counts in aerosols generated during dental operative procedures. Further randomised controlled clinical trials based on robust designs are required to establish the effectiveness of antimicrobial agents in reducing aerosol-related microbial loads (bacteria and viruses) in clinical environments.