This study aimed to test the efficacy of a mint-flavored mouthwash when it is used at bedtime for subsequent sleep in a field study setting, using a wristwatch-type heart rate (HR) monitoring devise. Using a within-subject experimental design, twenty healthy adults used three types of mouthwash having a different intensity of mint sensation (or water as a control) per one experiment night just before going to bed at their home environment, in a counterbalanced order. As for results, irrespective of the intensity of mint-flavored mouthwashes, the subjective score for “fatigue” and “refreshing” before sleep was decreased and increased, respectively. In addition, although a significant inhibition of HR decline in the sleep initiation period (0-30 minutes after bedtime) was observed with the use of mint-flavored mouthwashes compared with the control, the trend reversed subsequently as HR trended lower than for the control during 2-6 hour after the bedtime. These findings suggest that the using mint-flavored mouthwashes at bedtime induces a positive mood before sleep and may improve physiological sleep. Moreover, this study illustrated the possible application and significant advantage of the use of wristwatch-type heart rate monitoring devise in a context of field study.

Abstract Fusobacterium nucleatum promotes dental biofilm formation, increases the prevalence of periodontal disease, and is associated with systemic diseases such as colorectal cancer. However, the relationships of F. nucleatum in saliva with periodontal status and the composition of the salivary microbiome are unclear. Therefore, we analyzed these relationships in saliva samples collected from 611 subjects in Japan. Salivary DNA was extracted and the oral microbiome was analyzed using next-generation sequencing of 16S rRNA. The relationship between F. nucleatum and the community periodontal index was evaluated to examine effects on periodontal status, and α- and β-diversity were analyzed in three groups classified by relative abundance of F. nucleatum. Spearman rank correlation tests were used to examine relationships between the relative abundance of F. nucleatum and oral bacteria. Subjects with high levels of F. nucleatum had a higher prevalence of periodontitis compared with those with lower levels. β-diversity also differed between these two groups. F. nucleatum showed significant correlations with several periodontopathogens, including the red complex, P. intermedia, F. alocis and Fretibacterium ssp.. These results suggest that the relative abundance of F. nucleatum in saliva is associated with periodontal status and the composition of the salivary microbiome, including the red complex and periodontopathogens.

This study aimed to investigate the effect of flavored mouthwash on peripheral and cardiac autonomic nervous system activity. In a within-subject experimental design, 10 male and 10 female healthy adults went through two types of mouthwashes, one was with citrus mint flavor and another was with spice mint flavor, right after performing a 20-minute calculation task given as a cognitive stressor. Along with subjective evaluation, skin conductance and electrocardiogram was recorded throughout the experiment. Although there was no difference in the subjective stress levels between the two conditions, the level of skin conductance decreased more remarkably and significantly during the recovery period when the participants used citrus mint mouthwash. The findings suggest that a particular flavored mouthwash may provide physiological effect on user regardless of its subjective sensation and the citrus mint type mouthwash might be better suited for use in need of a relaxation.

Rachel Chau explores the connection between oral health and athletic performance

Povidone-iodine (PVP-I) is used for infection control and preoperative sterilization of the oral and pharyngeal regions. Marketed preparations containing cetylpyridinium chloride (CPC) are used to inhibit growth of oral bacteria. We conducted an in vitro study of the sterilizing effects of these microbicides on 10 oral bacterial strains and fungi related to pneumonia and periodontal disease, after dilution with phosphate-buffered saline (PBS), saliva, and components in saliva. The CPC solution was evaluated at 50 mg/100 mL, which is the concentration used in products. CPC sterilized all strains within 1 minute. Prolongation of the sterilization time associated with dilution was more gradual in comparison to PVP-I solution. CPC sterilized 7 of 10 microbial strains within 3 minutes at 3 mg/100 mL. At 500 mg/100 mL, which is near the upper limit of the concentration that is actually used, PVP-I solution sterilized 7 microbial strains within 3 minutes. However, PVP-I had no sterilization effect when diluted to 100 mg/100 mL or lower. With addition of saliva, PVP-I sterilized 2 microbial strains within 3 minutes at 500 mg/100 mL, whereas CPC solution sterilized 9 microbial strains within 1 minute at 50 mg/100 mL. Our results show that in use influenced by dilution with saliva, CPC is likely to maintain a strong sterilization effect, whereas PVP-I may have a reduced effect.