Contamination of Dental Surgical Masks by Aerosols Generated During Different Dental Treatments

TL;DR

This study measured how many microbes land on dental masks during treatments and found that hygiene measures are effective, but suction helps reduce contamination.

Contribution

The study quantifies microbial contamination on masks during dental treatments and identifies factors influencing it.

Findings

On average, 5.41 CFUs were found on masks, mostly oral bacteria.

Staphylococcus aureus was detected on 16 masks.

Dental assistants' masks had fewer CFUs than dentists' masks.

Abstract

The COVID-19 pandemic raised the question about the extent of microbial exposure encountered by dentists during dental therapy. The purpose of this study was to quantify microbial counts on surgical masks related to duration and type of dental therapy, as well as patient oral health variables.

Sterile filter papers were fixed on surgical masks used during routine daily dental therapy. Thereafter, the filter papers were pressed onto blood agar plates for 1 min, before the agar plates were incubated with 10% CO2. After 48 h, the colony forming units (CFU) were counted and microorganisms were identified. The dependence of the CFU counts on treatment and patient-related variables was analysed using linear regression.

Filter papers obtained from 322 dental treatments (429 masks) were included in the final analysis. On average, 5.41 ± 9.94 CFUs were counted. While mostly oral bacteria were detected, Staphylococcus aureus was also identified on 16 masks. Linear regression, incorporating patient-related and treatment characteristics through step-wise inclusion, revealed statistical significance (p < 0.001) only with the variable “assistance during therapy”. The type of dental treatment exhibited a trend, with fewer CFUs observed in caries treatment compared to periodontal or prosthodontic therapy. Furthermore, after analysing filter papers from masks used by dental assistants in 107 dental treatments, fewer CFUs were found on the masks compared to those used by dentists (p < 0.001).

The mean number of CFUs observed consistently remained low, highlighting the efficacy of the implemented hygiene measures. Consequently, it is clinically recommended to support dental treatment with precise suction of the generated aerosols.

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