Impacts of sleep on the characteristics of dental biofilm

Maki Sotozono,Mikako Hayashi,Nanako Kuriki,Shota Nakamura,Yuichiro Noiri,Yoko Asahi,Hiroyuki Machi,Shigeyuki Ebisu,Tetsuya Iida,Daisuke Motooka

doi:10.1038/s41598-020-80541-5

Maki Sotozono, Mikako Hayashi + Show 8 more

Open Access

https://doi.org/10.1038/s41598-020-80541-5

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Abstract

Dental biofilm present on the tooth surface is associated with oral diseases, such as dental caries and periodontal disease. Because bacterial numbers rapidly increase in saliva during sleep, oral care before sleeping is recommended for the prevention of chronic oral diseases. However, temporal circadian changes in the quantity and quality of dental biofilms are poorly understood. This study aimed to investigate the impacts of sleeping on dental biofilm amounts and compositions by using an in situ model. The use of this in situ model enabled us to investigate dental biofilm formed in the oral cavity and to perform a quantitative analysis. Subjects began wearing oral splints in the morning or before sleeping, and biofilm samples were collected at 8, 16, and 24 h after the subjects began wearing oral splints; these samples were then used in various experiments. No significant changes in the numbers of biofilm-forming bacteria were caused by sleep. However, the relative abundances of genera related to periodontitis (i.e., Fusobacterium and Prevotella) increased after awakening. In conclusion, the numbers of biofilm-forming bacteria were not affected by sleep, and the abundances of obligate anaerobes increased after sleep. This research may aid in defining efficacious preventive oral care.

Highlights

Dental biofilm present on the tooth surface is associated with oral diseases, such as dental caries and periodontal disease
Dental biofilm that forms on the tooth surface is thought to be associated with oral diseases, such as dental caries and periodontal diseases[9,10], which are chronic infectious diseases found in many patients worldwide[11]
Dental caries were found to result from a dysbiosis with acidogenic and aciduric bacteria, whereas periodontitis is triggered by dysbiosis with proteolytic, obligate anaerobic, and alkaliphilic b acteria[17]

Summary

Introduction

Dental biofilm present on the tooth surface is associated with oral diseases, such as dental caries and periodontal disease. Because bacterial numbers rapidly increase in saliva during sleep, oral care before sleeping is recommended for the prevention of chronic oral diseases. Patients and clinicians generally agree on the need for oral care before sleep This practice is recommended solely based on the number of bacteria in saliva, and it does not consider the role of dental biofilm in the onset of oral disease. The salivary microbiome is reportedly associated with circadian o scillation[27]; there remains a lack of information regarding the relationship between dental biofilm and the circadian rhythm, as well as regarding the roles of changes in the abilities of dental biofilms to cause oral disease between waking and sleeping hours. The effects of sleep on the characteristics of dental biofilm have not been sufficiently investigated owing to the difficulty of such experiments

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