Effects of cleaning sports mouthguards with ethylene-vinyl acetate on oral bacteria

Hiroki Hayashi; Yoshikazu Naiki; Masahiro Murakami; Akihiro Oishi; Rihoko Takeuchi; Masayoshi Nakagawa; Suguru Kimoto; Yoshiaki Hasegawa; Akizumi Araki

doi:10.7717/peerj.14480

Effects of cleaning sports mouthguards with ethylene-vinyl acetate on oral bacteria

PeerJ. 2022 Dec 5:10:e14480. doi: 10.7717/peerj.14480. eCollection 2022.

Authors

Hiroki Hayashi^{1

2}, Yoshikazu Naiki¹, Masahiro Murakami^{1

3}, Akihiro Oishi¹, Rihoko Takeuchi^{1

3}, Masayoshi Nakagawa², Suguru Kimoto^{2

3}, Yoshiaki Hasegawa¹, Akizumi Araki²

Affiliations

¹ Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.
² Department of Fixed Prosthodontics and Oral Implantology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.
³ Department of Gerodontology and Home Care Dentistry, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.

Abstract

Background: Sports mouthguards, worn in the oral cavity to prevent sports injuries, are constantly exposed to various microorganisms that cause oral infections. Hence, the optimal cleaning methods for sports mouthguards have been thoroughly examined. In this study, we evaluated the efficiency of cleaning effects with a mouthguard cleaner (MC) on microbial biofilm formation in sports mouthguards in vitro and in vivo.

Methods: We evaluated the cleaning effects of the discs produced by ethylene-vinyl acetate (EVA) on bacterial biofilms formed by the commensal bacterium Streptococcus oralis, the cariogenic bacterium Streptococcus mutans, and the opportunistic pathogen Staphylococcus aureus in vitro. EVA discs with biofilm were subjected to sterile distilled water (CTRL) and ultrasonic washing (UW), followed by treatment with MC and sodium hypochlorite (NaClO) as positive controls. Thereafter, the viable bacterial cell counts were determined. The bacteria adhering to the sheets before and after the treatment were observed under an electron microscope. The degree of cleanliness and measurement of viable microbial cell counts for total bacteria, Streptococci and Candida, opportunistic fungi, were evaluated on the used experimental sports mouthguards with and without UW and MC treatment in vivo.

Results: The number of bacterial cells significantly decreased against all the tested biofilm bacteria upon treatment with MC, compared with CTRL and UW. Electron microscopy analysis revealed the biofilm formation by all bacteria on the EVA discs before cleaning. We observed fewer bacteria on the EVA discs treated with MC than those treated with CTRL and UW. Furthermore, the degree of cleanliness of the used experimental sports mouthguards cleaned using MC was significantly higher than that of the CTRL-treated mouthguards. Moreover, the viable microbial cell counts on the used experimental sports mouthguard were considerably lower than those on the CTRL ones.

Conclusion: The cleaning effect of MC against oral bacteria was more effective than that of UW. MC treatment might have a potential future application as a cleaning method for sports mouthguards to protect athletes from oral infection.

Keywords: Biofilm; Candida; Ethylene-vinyl acetate; Sports mouthguard; Streptococci.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Ethylenes / pharmacology
Humans
Sports*
Streptococcus
Vinyl Compounds

Substances

vinyl acetate
Vinyl Compounds
Ethylenes

Grants and funding

This study was supported by JSPS KAKENHI grant No. 20K09931 (Yoshiaki Hasegawa). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.