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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. 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. 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. 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. 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.

Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine slabs (n = 12 per group) mounted in the same well of culture plates. The biofilms were exposed 8×/day to 10% sucrose and treated 2×/day with fluoridated solutions containing 0, 150, 450, or 1,350 ppm F; thus, simulating the use of low to high fluoride concentration toothpastes. The pH values of the culture medium was monitored 2×/day as a biofilm acidogenicity indicator. After 96 h, biofilms were collected for fluoride concentration analysis. The percentage of surface hardness loss (%SHL) was calculated for slabs. The fluoride uptake by the enamel and dentine was also determined. The model showed a dose-response because the biofilm and fluoride uptake increased and %SHL decreased at increasing fluoride concentrations (p < 0.05). Fluoride in the biofilm formed on dentine and fluoride uptake by dentine were higher than those for enamel. With the same fluoride concentration treatment, the percentage of reduction of demineralization was lower for dentine than for enamel. In conclusion, the model was validated in terms of a dose-response effect of fluoride on enamel and root dentine. Furthermore, the findings support the clinical data, suggesting that higher fluoride concentrations are necessary to control caries of root dentine than of enamel.

Oral Microbiology At A Glance is a title in the highly popular at a Glance series. It provides a concise and accessible introduction and revision aid. Following the familiar, easy-to-use at a Glance format, each topic is presented as a double-page spread with key facts accompanied by clear diagrams encapsulating essential information. Systematically organized and succinctly delivered, Oral Microbiology At A Glance covers: Oral microbial origins of health or disease Various infections ranging from dental caries, periodontal and endodontic infections to oral mucosal, bone, and systemic infections Local and systemic extensions of oral infections Sterilization, disinfection, infection control methods, and bioterrorism Oral Microbiology At A Glance is the ideal companion for students of microbiology, all students of dentistry, and early career clinicians. In addition the text will provide valuable insight for general dental practitioners wanting to update their knowledge of oral microbiology and immunology, as well as dental hygienists, therapists and technicians.

Black tooth stain is a characteristic extrinsic discoloration commonly seen on the cervical enamel following the contour of the gingiva. To investigate the relationship between black tooth stain and the oral microbiota, we used 16S rRNA gene sequencing to compare the microbial composition of dental plaque and saliva among caries-free children with and without black stain. Dental plaque and saliva, as well as black stain, were sampled from 10 children with and 15 children without black stain. Data were analyzed using the pipeline tool MOTHUR. Student's t-test was used to compare alpha diversities and the Mann-Whitney U test to compare the relative abundances of the microbial taxa. A total of 10 phyla, 19 classes, 32 orders, 61 families and 102 genera were detected in these samples. Shannon and Simpson diversity were found to be significantly lower in saliva samples of children with black stain. Microbial diversity was reduced in the black stain compared to the plaque samples. Actinomyces, Cardiobacterium, Haemophilus, Corynebacterium, Tannerella and Treponema were more abundant and Campylobacter less abundant in plaque samples of children with black stain. Principal component analysis demonstrated clustering among the dental plaque samples from the control group, while the plaque samples from the black stain group were not and appeared to cluster into two subgroups. Alterations in oral microbiota may be associated with the formation of black stain.

  [...]chronic periodontitis is characterized by gum swelling and bleeding on probing, gingival recession, and deep pockets between the teeth and the gums that lead to loosening of the teeth and, ultimately, tooth loss [1]. [...]in light of these recent findings, it is paramount that future research be directed toward improving our understanding of the links between periodontitis and other chronic inflammatory diseases.

Spatial and temporal patterns in microbial communities provide insights into the forces that shape them, their functions and roles in health and disease. Here, we used spatial and ecological statistics to analyze the role that saliva plays in structuring bacterial communities of the human mouth using >9000 dental and mucosal samples. We show that regardless of tissue type (teeth, alveolar mucosa, keratinized gingiva, or buccal mucosa), surface-associated bacterial communities vary along an ecological gradient from the front to the back of the mouth, and that on exposed tooth surfaces, the gradient is pronounced on lingual compared to buccal surfaces. Furthermore, our data suggest that this gradient is attenuated in individuals with low salivary flow due to Sjögren’s syndrome. Taken together, our findings imply that salivary flow influences the spatial organization of microbial communities and that biogeographical patterns may be useful for understanding host physiological processes and for predicting disease. Oral microbial communities are excellent sites for examining the mechanisms of structural variation in the microbiota. Here, the authors use spatial and ecological analysis to examine over 9000 dental and mucosal microbiota samples. They find that saliva plays a key role in structuring bacterial communities in the mouth.

Direct interfacing of nanosensors onto biomaterials could impact health quality monitoring and adaptive threat detection. Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show that graphene can be printed onto water-soluble silk. This in turn permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel. The result is a fully biointerfaced sensing platform, which can be tuned to detect target analytes. For example, via self-assembly of antimicrobial peptides onto graphene, we show bioselective detection of bacteria at single-cell levels. Incorporation of a resonant coil eliminates the need for onboard power and external connections. Combining these elements yields two-tiered interfacing of peptide–graphene nanosensors with biomaterials. In particular, we demonstrate integration onto a tooth for remote monitoring of respiration and bacteria detection in saliva. Overall, this strategy of interfacing graphene nanosensors with biomaterials represents a versatile approach for ubiquitous detection of biochemical targets. Graphene is characterized by unique physical properties that offer substantial promise, most notably for electronic applications. Mannoor et al . present a wireless graphene-based sensor for detecting bacteria on a range of biological tissues.

Periodontitis is a common chronic infection of tooth-supporting tissues leading to tooth loss. Two of the major periodontal pathogens are Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Clinically diagnosed periodontitis has been associated with metabolic syndrome (MetS). The aim of the study was to investigate the association of serum antibody levels against A. actinomycetemcomitans and P. gingivalis and the number of missing teeth with MetS. The population was the PAIS subcohort of the FINRISK ‘97 study ( n  = 1,354). The subjects were men aged 45–74 years, and they participated in this cardiovascular risk factor survey in Finland. A total of 534 (39 %) subjects had MetS defined according to the guidelines of the International Diabetes Federation. Serum antibody levels against the pathogens were measured by multiserotype ELISA. A. actinomycetemcomitans antibody levels and the number of missing teeth were significantly higher in subjects with a large waist circumference or with low serum high-density lipoprotein cholesterol. The number of missing teeth was also higher among subjects with a high serum triglyceride concentration or high plasma glucose concentration. Seropositivity for A. actinomycetemcomitans was significantly associated with MetS with an odds ratio (OR) 1.42 (95 % confidence interval 1.09–1.85, p  = 0.009). More than four missing teeth and complete edentulousness were also significantly associated with MetS with ORs 1.69 (1.26–2.27, p  < 0.001) and 1.93 (1.30–2.86, p  = 0.001), respectively. Missing teeth and systemic exposure to A. actinomycetemcomitans were associated with several components of Mets. Infection with this common pathogen or the host response against it is associated with the presence of MetS.

The use of natural substance to ward off microbial infections has a long history. However, the large-scale production of natural extracts often reduces antibacterial potency, thus limiting practical applications. Here we present a strategy for converting natural organosulfur compounds into nano-iron sulfides that exhibit enhanced antibacterial activity. We show that compared to garlic-derived organosulfur compounds nano-iron sulfides exhibit an over 500-fold increase in antibacterial efficacy to kill several pathogenic and drug-resistant bacteria. Furthermore, our analysis reveals that hydrogen polysulfanes released from nano-iron sulfides possess potent bactericidal activity and the release of polysulfanes can be accelerated by the enzyme-like activity of nano-iron sulfides. Finally, we demonstrate that topical applications of nano-iron sulfides can effectively disrupt pathogenic biofilms on human teeth and accelerate infected-wound healing. Together, our approach to convert organosulfur compounds into inorganic polysulfides potentially provides an antibacterial alternative to combat bacterial infections. Garlic has a mild antibacterial activity due to its organosulfur content. Here, the authors develop an approach to convert natural organosulfur into iron-sulfur nanosheets, with significantly higher antibacterial activity that can be used against infections as well as biofilms.

In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans , one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation—virulence determinants of S. mutans —are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein–bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants “expression” from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?