key: cord-0960221-rd9rg9wb
authors: Rasaiah, Sabrina R.; Allison, James; Edwards, David C.
title: Endodontic procedures produce bacterial droplet contamination - but what about viruses?
date: 2021-06-25
journal: Evid Based Dent
DOI: 10.1038/s41432-021-0175-1
sha: c0cb1452490d02232f4e35df5dc1552c3f3ef198
doc_id: 960221
cord_uid: rd9rg9wb

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.

SARS-COV-2 is present in significant quantities in saliva. 1 Consequently, any dental procedure using a rotary handpiece inadvertently risks the spread of the virus through aerosols or droplets, posing a threat to both patients and clinicians. The lack of evidence on this topic 2 resulted in guidance to stop performing aerosol generating procedures (AGPs) at the start of the COVID-19 pandemic. Standard operating procedures are continuously evolving as new data and equipment are produced, which are facilitating dentistry's return to something that resembles 'normal practice'.

In the introduction of this paper, the authors demonstrate a compelling argument for the need of the study, particularly specific to the field of endodontics. Even when dentistry is restricted to urgent care, aerosol generating endodontic procedures remain essential to relieve patients' pain and infection.

The methods used in the study did not completely align with its stated aims. The authors used passive sampling with settle plates, which is reliable for detecting large droplets but has limitations for detecting aerosols; active sampling methods may have been more appropriate. 3 Both 'procedure' and 'time' are stated as variables, but these are not investigated independently. Furthermore, the study aimed to identify the distance that bioaerosols can spread, but only investigated microorganisms at 0.5 m and 2 m and Endodontic procedures produce bacterial droplet contamination -but what about viruses? Sabrina R. Rasaiah, 1 James Allison 2 and David C. Edwards* 3

• Bacterial contamination during endodontic procedures is highest closest to the patient's mouth. • Bacterial contamination increases as the length of a procedure increases. • This case-control study does not add to our knowledge of viral bioaerosol generation during endodontic procedures.

RT-qPCR assays based on saliva rather than on nasopharyngeal swabs are possible but should be interpreted with caution: results from a systematic review and meta-analysis

A systematic review of droplet and aerosol generation in dentistry

Dental aerosols: microbial composition and spatial distribution

Evaluating contaminated dental aerosol and splatter in an open plan clinic environment: Implications for the COVID-19 pandemic

COVID-19: infection prevention and control dental appendix