Contamination of surgical mask during aerosol-producing dental treatments

Abstract

Objectives Surgical masks are usually contaminated during dental treatment. So far it has not been investigated whether a surgical mask itself can be a source of microbial transmission. The aim of this study was therefore to investigate the microbiological contamination of surgical masks during dental treatment and the transfer of microorganisms from the mask to the hands. Materials and methods Five dental treatment modalities were studied: carious cavity preparation (P-caries, n = 10), tooth substance preparation (P-tooth, n = 10), trepanation and root canal treatment (P-endo, n = 10), supragingival ultrasonic application (US-supra, n = 10), and subgingival periodontal ultrasonic instrumentation (US-sub, n = 10). Bacterial contamination of mask and gloves worn during treatment was tested by imprinting on agar plates. Additionally, before masks were tested, their outer surface was touched with a new sterile glove. This glove was also imprinted on agar. Bacteria were identified by MALDI TOF mass spectrometry. Colony-forming units (CFU) were scored: score 0: 0 CFU, score 1: < 102 CFU, score 2: > 102 CFU, score 3: dense microbial growth. Results All masks and all gloves used during treatment displayed bacterial contamination (sample scores 0/1/2/3: masks 0/46/3/1 and gloves 0/31/10/9). After touching the masks with new sterile gloves, microorganisms were recovered with the following contamination scores: P-caries: 4/6/0/0, P-tooth: 2/8/0/0: P-endo: 7/3/0/0, US-supra: 0/9/1/0, US-sub: 2/8/0/0. No statistically significant differences were detected between the treatment modalities. Streptococci spp. and Staphylococci spp. representing the oral and cutaneous flora dominated. Conclusions Surgical masks are contaminated after aerosol-producing dental treatment procedures. Used masks have a potential to be a source of bacterial contamination of the hands. Clinical relevance Dental staff should avoid touching the outer surface of masks with their hands to prevent transmission of pathogens. It is recommendable to change the mask after each treated patient followed by hand disinfection.

Bacterial contamination of the surgical mask and forehead in aerosol-producing conservative-preventive dental treatment

“…It was detected in fty forehead swab and 32 surgical mask samples. This high detection rate is in line with results from other studies [2,23]. S. epidermidis is the most common member of the coagulase-negative staphylococci found on human epithelial surfaces and must be considered an important nosocomial pathogen [24].…”

“…Dental professionals are exposed to numerous potentially infectious factors [1] and personal protective equipment (PPE) is regularly contaminated during aerosol-producing dental treatment [2]. In this context, avoiding exposure of the airways, eyes and skin to potentially infectious agents, in particular to bacteria and respiratory viruses, is of paramount importance [3].…”

“…In contrast to gloves, the correct use of surgical masks has not been a major issue so far. There are only few recommendations on the use of surgical masks in medicine and in dentistry [2,14,15] and very few systematic studies on their correct use. One study demonstrated that bacteria accumulate on the outer surface of the surgical mask during prolonged use for more than two hours, a typical duration in many surgical disciplines [15].…”

“…In dentistry, however, the surgical mask is (1) usually worn for shorter periods of time, (2) frequently used in virtually every patient, and (3) regularly contaminated with microbial aerosols and patient´s saliva or blood during treatment. Aerosol-borne microorganisms from oral cavity released during dental treatment survive on the outer surface of surgical masks [2]. Moreover, to the best of our knowledge, no previous study has investigated the bacterial load on dental professionals' foreheads after performing aerosol-generating dental treatments.…”

Nanoparticles-Based Face Masks and Respirators for Preventing COVID-19 Transmission: Breathability Versus Biocidal Activities

“…15,19,23,24,27,28,69 Based on those studies, the employment of various NPs could effectively kill the bacteria, including multidrug-resistant S. epidermidis and S. aureus. 70,71 Inhibition mechanism of the bacteria depends on the type of NPs. For instance, Ag NPs could cause bacterial cell death by interfering the cell respiratory system, interfering ATP production and DNA replication, increasing cell membrane permeability, and generating bacterial cell-derived reactive oxygen species (ROS).…”