Endodontic procedures produce bacterial droplet contamination - but what about viruses?

Research question The study aims to investigate spread, distance and spatial distribution of aerosolised microorganisms generated through various endodontic procedures. Study design A case-control study carried out at the University of Maryland, US in 2020. The study investigated the aerosolised microorganisms produced during three endodontic treatments: emergency pulpotomy, emergency pulpectomy and non-surgical root canal therapy (NSRCT), with 15 participants in each group (n = 45). Patients diagnosed with symptomatic apical periodontitis were included. The use of settle plates for passive air sampling was employed, in a 4 x 4 m room with closed doors. The number of colony-forming units (CFUs) and composition of bacterial species were analysed. Variables within the study included: distance of plate to patient's mouth (0.5 m or 2 m), positioning of plate (directly in front of or diagonal to the participant's mouth), type of endodontic treatment performed and the duration of treatment. A baseline sample was collected (room at rest) as a control. All dental treatment was carried out under rubber dam, after patients had undergone a pre-operative 0.12% chlorhexidine digluconate mouth rinse for 60 seconds. An extraoral suction system (ADS EOS Dental System Inc; Ontario, CA, USA) was also placed directly in front of the patient's mouth throughout treatment. Results A significantly greater number of CFUs were recorded after endodontic treatments (all treatments), compared to negative control. CFUs were lower in the emergency pulpotomy group compared to the other two groups. There was a significantly lower number of CFUs found at plates situated 0.5 m, compared to 2 m, away from the patient. There was a positive correlation between the procedure duration and CFU count. The main bacterial species detected were Staphylococcus aureus (48.8%), Staphlococcus epidermidis (42.2%) and oral streptococci (33.1%). Pseudomonas aeruginosa and fungi were not detected. Conclusion Emergency pulpectomy and NSRCT created greater microbial contamination than an emergency pulpotomy. Greater numbers of microorganisms were found after longer treatment times and closer to the patient's mouth.