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Background: Using salivary microbiota as an accurate proxy for monitoring supragingival microbiota remains controversial because their relationship remains unclear. The eruption of permanent teeth and the exfoliation of primary teeth in mixed dentition greatly alter microbial habitats, which may cause compositional shifts of oral microbiota from childhood to adults., Objective: This study's purpose was to assess whether saliva represents a suitable sample for monitoring supragingival microbiota in healthy people, and to explore how the replacement process of deciduous teeth with permanent teeth in mixed dentition influences microbiota within the oral cavity., Design: Samples of saliva and of supragingival plaque from permanent and deciduous teeth were collected separately from 20 healthy children with mixed dentition. To characterize their microbial communities, we used the V3-V4 hypervariable region of the bacterial 16S rRNA gene sequence., Results: Saliva harbored a less even and less diverse community than did the plaque. Discriminating genera, namely Rothia and Streptococcus, contributed to the saliva and plaque differentiation. About half of predicted KEGG pathways varied between the plaque and saliva communities. Oral bacteria showed significantly associations between their supragingival and salivary states. We identified 20 supragingival plaque-related genera in saliva, such as Corynebacterium, Capnocytophaga, Fusobacterium, and Neisseria. Additionally, the relative abundance of Actinobacteria peaked in the permanent teeth plaque but subsided in deciduous teeth plaque and saliva. The exfoliation of deciduous teeth and eruption of permanent teeth might be related to the reported fluctuation in the relative abundance of Actinobacteria from primary dentition to permanent dentition within the oral cavity. The variation between PT and DT was due mainly to permanent teeth being enriched in Actinomyces and deciduous teeth in Treponema., Conclusion: These results suggested that the supragingival plaque-related bacteria could be suitable candidates when sampling saliva for monitoring supragingival microbiota. The replacement process of deciduous teeth with permanent teeth in mixed dentition might be related to the reported age-maturation of phylum Actinobacteria in the oral cavity., Competing Interests: The authors have declared that no competing interests exist.

Oral microbiota that established in the early years of life may influence the child's oral health in the long term. Until now, no consensus is reached about whether the development of the oral microbiota is more related with age increase or more with teeth eruption. To analyze the microbiota development of both saliva and supragingival plaque during the gradual eruption of primary teeth in caries-free infants and toddlers. Saliva and plaque samples were collected at five and four dentition states, respectively, and were identified by bacterial 16S rRNA gene sequencing. During the longitudinal observation, the saliva ecosystem seemed more complex and dynamic than the plaque, with larger bacteria quantity and more significantly varied species over time. About 70% of the initial colonized OTUs in plaque persisted until the completion of the primary dentition. Transient bacteria were mostly detected in the early saliva and plaque microbiota, which came from the environment and other sites of the human body. Microbial diversity in both saliva and plaque varied greatly from pre-dentition to full eruption of eight anterior teeth, but not during the eruption of primary molars. Oral bacterial development follows an ordered sequence during the primary teeth eruption. 'Fully eruption of all primary anterior teeth' is a critical stage in this process. [ABSTRACT FROM AUTHOR]

Tonsillar hypertrophy is a common disease in 3-to-6-year-old children, which may cause serve symptoms like airway obstruction. Microbiological factors play an important role in the etiology of tonsillar hypertrophy. As the starting point of digestive and respiratory tracts, the microbial composition of the oral cavity is not only unique but also closely related to the resident microbiota in other body sites. Here we reported a correlation study of the microbiota between oral cavity and tonsils in children with tonsillar hypertrophy. Saliva, supragingival plaque, and wiped samples from the tonsil surface were collected from both tonsillar hypertrophy patients and participants with healthy tonsils and were then analyzed using Illumina Miseq Sequencing of the 16S rRNA gene. In the tonsillar hypertrophic state, more genera were detected on the tonsil surface than in the tonsil parenchyma, with more intra-microbiota correlations. When tonsillar hypertrophy occurred, both the oral cavity and tonsil surface endured microbiome shift with increased genera category and more active bacterial interactions. Over half of the newly detected genera from the tonsillar hypertrophic state were associated with infection and inflammation process or exhibited antibiotic-resistant characters. Of each individual, the microbial composition and structure of saliva seemed more similar to that of the tonsil surface, compared with the supragingival plaque. In salivary microbiota, genus Johnsonella might be relative with the healthy state of tonsils, while Pseudoxanthomonas might be relative with tonsillar hypertrophy. Our study supported the link between oral microbiota with the healthy and hypertrophic states of tonsils and may provide new directions for future researches in the specific role of oral microbiota in the etiology of tonsil diseases. [ABSTRACT FROM AUTHOR]

The development of new bioelectronic platforms for direct interactions with oral fluid could open up significant opportunities for healthcare monitoring. A tongue depressor is a widely used medical tool that is inserted into the mouth, where it comes into close contact with saliva. Glucose is a typical salivary biomarker. Herein, we report—for the first time—a tongue depressor-based biosensor for the detection of glucose in both phosphate buffer and real human saliva. Carbon nanotubes (CNTs) are attractive electronic materials, with excellent electrochemical properties. The sensor is constructed by printing CNTs and silver/silver chloride (Ag/AgCl) to form three electrodes in an electrochemical cell: Working, reference, and counter electrodes. The enzyme glucose oxidase (GOD) is immobilized on the working electrode. The glucose detection performance of the sensor is excellent, with a detection range of 7.3 μM to 6 mM. The glucose detection time is about 3 min. The discretion between healthy people's and simulated diabetic patients' salivary samples is clear and easy to tell. We anticipate that the biosensor could open up new opportunities for the monitoring of salivary biomarkers and advance healthcare applications. [ABSTRACT FROM AUTHOR]