Turbidity of mouthrinsed water as a screening index for oral malodor

Dysbiosis of oral microbiome persists after dental treatment-induced remission of periodontal disease and dental caries

IMPORTANCE

We characterized the oral conditions, salivary microbiome, and metabolome after dental treatment by investigating the state after treatment completion and transition to self-care. Dental treatment improved oral health conditions, resulting in oral disease remission; however, the imbalanced state of the salivary microbiome continued even after remission. Although the results of this study are preliminary, owing to the small number of participants in each group when compared to larger cohort studies, they indicate that the risk of disease may remain higher than that of healthy participants, thereby demonstrating the importance of removing dental plaque containing disease-related bacteria using appropriate care even after treatment completion. We also identified bacterial species with relative abundances that differed from those of healthy participants even after remission of symptoms, which may indicate that the maturation of certain bacterial species must be controlled to improve the oral microbiome and reduce the risk of disease recurrence.

ORGANOLEPTIC AND HALITOMETRIC ASSESSMENTS DO NOT CORRELATE WELL IN INTRA-ORAL HALITOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

The gold standard method for diagnosing oral halitosis is the subjective organoleptic measurement. Device-supported methods are also widespread worldwide. The challenges and safety concerns around performing organoleptic measurements during pandemics and the diversity of measuring device alternatives raised our clinical question: which halitometer is the most suitable for diagnosing halitosis?

METHODS

This systematic review was registered in PROSPERO (ID CRD42022320024). The search was performed on March 23, 2022 in the following electronic databases: MEDLINE, Embase, Scopus, Web of Science, and CENTRAL. Adult populations with or without halitosis were included, and patients with systemic diseases were excluded. Organoleptic (subjective) measurement and the device-supported (objective) methods were compared; the primary outcome was the correlation coefficient, and the secondary was the specificity and sensitivity of the devices. QUADAS-2 and QUADAS-C were used to evaluate the risk of bias in the studies. Random-effects meta analyses were performed on the outcomes, and the secondary outcomes were plotted on a common ROC plot.

RESULTS

A total of 1231 records were found in the 5 databases. After the selection process, 76 articles were eligible for the systematic review, and 14,635 patients were involved in the qualitative analysis. The pooled Spearman's correlation coefficient (c.c.) for sulfide monitors was 0.65; 95% CIs: [0.53-0.74]; I2 = 95%, P < .01. The pooled Spearman's c.c. for portable gas chromatographs was 0.69; 95% CIs: [0.63-0.74]; I2 = 12%, P < .01. The pooled Spearman's c.c. for gas chromatographs was 0.76; 95% CIs: [0.67-0.83]; I2 = 0%, P < .01.

DISCUSSION

None of the most commonly used halitometers proved to be significantly superior to the others. Halimeter and OralChroma measurements did not correlate well with the organoleptic level of oral halitosis in adults. Therefore, better halitometers need to be developed as an alternative to organoleptic measurements.

An in vitro study of the effects of Phellodendron bark extract and berberine chloride on periodontal pathogenic bacteria in the oral microbiome

OBJECTIVES

Periodontal disease is triggered by oral microbiome dysbiosis. Thus, to prevent its onset, it is important to maintain relative abundance of periodontal pathogenic bacteria in the oral microbiome at a low level. While Phellodendron bark extract (PBE) and its active ingredient, berberine, exert antibacterial effects on periodontal pathogenic bacteria, such as Porphyromonas gingivalis, their effects on the oral microbiome as a whole remain unknown. Therefore, we aimed to clarify the potential of PBE and berberine chloride (BC) in regulating the relative abundance of periodontal pathogenic bacteria in the oral microbiome.

METHODS

Saliva was collected from 20 participants. Each participant's saliva was combined separately with P. gingivalis suspension and either PBE or BC in a modified basal medium. The samples were then incubated under anaerobic conditions for 24 h. After cultivation, we determined the total bacterial concentration using quantitative polymerase chain reaction analysis and the bacterial composition using 16 S ribosomal RNA gene sequencing.

RESULTS

The total bacterial concentration was reduced because of treatment with PBE and BC. Bacterial 16 S ribosomal RNA gene sequencing confirmed that treatment with PBE and BC significantly reduced the relative abundance of periodontal pathogenic bacteria, including red and orange complex bacteria.

CONCLUSIONS

Our findings suggest that PBE and BC reduce the relative abundance of periodontal pathogenic bacteria in the oral microbiome. Thus, PBE and BC can aid in preventing periodontal disease, given their ability to regulate the oral microbiome composition and their anti-inflammatory effects.

Characterization of oral bacteria in the tongue coating of patients with halitosis using 16S rRNA analysis

There are many studies on the relationship between the tongue coating and halitosis, but few have evaluated the bacterial community present in the tongue coating. This study identified bacteria in the tongue coating in individuals with and without halitosis using 16S rRNA analysis. Forty subjects (mean age, 46.1 ± 15.8 years) who visited the halitosis clinic at the University Dental Hospital between 2016 and 2017 were divided into halitosis (n = 32) and non-halitosis (n = 8) groups according to results from an organoleptic test (OT). Additional measurements via gas chromatography (GC) and the Breathtron® instrument confirmed the groupings as the H₂S, CH₃SH, (CH₃)₂S, and total volatile sulphur compounds (VSC) levels were significantly higher in the halitosis group than in the non-halitosis group. Bacterial diversity was higher in the halitosis group; the median (quartile) values of the Shannon index were 4.46 (4.21, 4.67) in the halitosis group and 3.80 (3.45, 4.30) in the non-halitosis group. Additionally, the median (quartile) values of the Chao-1 index were 84.0 (77.2, 95.0) in the halitosis group and 71.3 (65.0, 81.5) in the non-halitosis group. These differences in bacterial composition and diversity may further the understanding of causes and treatments for halitosis.

Comparison of oral microbiome profiles in stimulated and unstimulated saliva, tongue, and mouth-rinsed water

Epidemiological studies using saliva have revealed relationships between the oral microbiome and many oral and systemic diseases. However, when collecting from a large number of participants such as a large-scale cohort study, the time it takes to collect saliva can be a problem. Mouth-rinsed water, which is water that has been used to rinse the oral cavity, can be used as an alternative method for collecting saliva for oral microbiome analysis because it can be collected in a shorter time than saliva. The purpose of this study was to verify whether mouth-rinsed water is a suitable saliva substitute for analyzing the oral microbiome. We collected samples of mouth-rinsed water, stimulated saliva, unstimulated saliva, and tongue coating from 10 systemic healthy participants, and compared the microbial diversity and composition of the samples using next-generation sequencing of 16S rRNA-encoding genes. The results showed that the microbial diversity of mouth-rinsed water was similar to that of unstimulated and stimulated saliva, and significantly higher than that of tongue-coating samples. The microbial composition at the species level of mouth-rinsed water also showed a very high correlation with the composition of unstimulated and stimulated saliva. These results suggest that the mouth-rinsed water is a suitable collection method instead of saliva for oral microbiome analysis.