OBJECTIVES: This study aimed to analyze the bacteria in dental caries and establish an optimized dental-ca-ries diagnosis model based on 16S ribosomal RNA (rRNA) data of oral flora. METHODS: We searched the public databa-ses of microbiomes including NCBI, MG-RAST, EMBL-EBI, and QIITA and collected data involved in the relevant research on human oral microbiomes worldwide. The samples in the caries dataset (1 703) were compared with healthy ones (20 540) by using the microbial search engine (MSE) to obtain the microbiome novelty score (MNS) and construct a caries diagnosis model based on this index. Nonparametric multivariate ANOVA was used to analyze and compare the impact of different host factors on the oral flora MNS, and the model was optimized by controlling related factors. Finally, the effect of the model was evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: 1) The oral microbiota distribution obviously differed among people with various oral-health statuses, and the species richness and species diversity index decreased. 2) ROC curve was used to evaluate the caries data set, and the area under ROC curve was AUC=0.67. 3) Among the five hosts' factors including caries status, country, age, decayed missing filled tooth (DMFT) indices, and sampling site displayed the strongest effect on MNS of samples (P=0.001). 4) The AUC of the model was 0.87, 0.74, 0.74, and 0.75 in high caries, medium caries, low caries samples in Chinese children, and mixed dental plaque samples after controlling host factors, respectively. CONCLUSIONS The model based on the analysis of 16S rRNA data of oral flora had good diagnostic efficiency.
Humans ; Child ; Bacteria/genetics* ; Dental Caries/microbiology* ; Dental Caries Susceptibility ; Microbiota/genetics* ; RNA, Ribosomal, 16S

Objective: To detect and analyze the characteristics of oral microbiota in species composition, function and metabolism among caries, periodontitis and oral healthy individuals, hunting for the microbiome-derived biomarkers with specificity and sensitivity to estimate the occurrence of these two diseases. Methods: Saliva samples were collected from 10 patients with high caries risk [decayed-missing-filled teeth (DMFT)≥6, HC group] in Department of Endodontics, 10 patients with periodontitis of grade Ⅱ A-Ⅲ C (PG group) in Department of Periodontology and 10 oral healthy individuals (HH group) from School of Stomatology, The Fourth Military Medical University during from March 2022 to June 2022. A baseline examination was conducted on all participants, including their oral conditions of caries and periodontal health. Metagenomic sequencing (Illumina PE150 platform) and liquid chromatography-mass spectrometry were used to detect microorganisms and their metabolites in the samples respectively. The sequencing data were analyzed to obtain the information of microbial taxonomic composition, functional genes and metabolites in each group of samples. The basic oral conditions and saliva samples of subjects in each group were evaluated and collected by the same professional endodontist. Results: There were no significant difference in baseline characteristics such as age and sex among the subjects in each group (P>0.05). DMFT in HC group (9.0±1.7) was significantly higher than that in HH group (0) and PG group (0) (F=243.00, P<0.001). Sequencing data analysis showed that the taxonomic compositions of salivary microbiota in each group were mainly Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria at the phylum level, and Streptococcus, Neisseria, Rothia, Prevotella at the genus level. Differential analysis showed that, compared with the HH group, HC group and PG group had significant differences in taxonomic composition (P<0.05), and the most significant among them was Prevotella. At the species level, Prevotella pallens was the most significant change in HC group, and Porphyromonas gingivalis in PG group. Metabolite analysis showed that there were significant differences in metabolites between HC group and PG group. The results showed that, compared with the HH group, the most significant metabolite change was 3-hydroxy-1, 5-diphenylpentan-1-one in HC group (P=0.001) and N1 acetylspermine in PG group (P=0.002) respectively. Compared with the PG group, the metabolite of HC group with the most significant difference is D-glucosamine 6-phosphate (P=0.006). The metabolism gene function analysis showed that, the enrichment of carbohydrate metabolism related genes was highest in HC group, followed with HH group, and it was lowest in PG group. In addition, compared with the HH group, the abundance of functional genes related to glucose metabolism, such as ABC transporter and phosphotransferase system, were significantly decreased in PG group (P<0.05), but significantly increased in HC group (P<0.05). Conclusions: There is a significant correlation between the alternation of carbohydrate metabolism of salivary microbiota with the occurrence of caries and periodontitis. In the future, Prevotella pallens and 3-hydroxy-1, 5-diphenylpentan-1-one may be the potential biomarkers of caries; while Porphyromonas gingivalis and N1 acetylspermine work in the predictions of periodontitis.
Humans ; Saliva/microbiology* ; Dental Caries Susceptibility ; Periodontitis/microbiology* ; Microbiota/genetics* ; Porphyromonas gingivalis/genetics* ; RNA, Ribosomal, 16S/genetics*

Oral bacteria directly affect the disease status of dental caries and periodontal diseases. The dynamic oral microbiota cooperates with the host to reflect the information and status of immunity and metabolism through two-way communication along the oral cavity and the systemic organs. The oral cavity is one of the most important interaction windows between the human body and the environment. The microenvironment at different sites in the oral cavity has different microbial compositions and is regulated by complex signaling, hosts, and external environmental factors. These processes may affect or reflect human health because certain health states seem to be related to the composition of oral bacteria, and the destruction of the microbial community is related to systemic diseases. In this review, we discussed emerging and exciting evidence of complex and important connections between the oral microbes and multiple human systemic diseases, and the possible contribution of the oral microorganisms to systemic diseases. This review aims to enhance the interest to oral microbes on the whole human body, and also improve clinician's understanding of the role of oral microbes in systemic diseases. Microbial research in dentistry potentially enhances our knowledge of the pathogenic mechanisms of oral diseases, and at the same time, continuous advances in this frontier field may lead to a tangible impact on human health.
Bacteria ; Dental Caries/microbiology* ; Humans ; Microbiota ; Mouth/microbiology* ; Mouth Diseases/microbiology* ; Periodontal Diseases/microbiology*

Streptococcus mutans is a well-known cause of dental caries, due to its acidogenicity, aciduricity, and ability to synthesize exopolysaccharides in dental plaques. Intriguingly, not all children who carry S. mutans manifest caries, even with similar characteristics in oral hygiene, diet, and other environmental factors. This phenomenon suggests that host susceptibility potentially plays a role in the development of dental caries; however, the association between host genetics, S. mutans, and dental caries remains unclear. Therefore, this study examined the influence of host gene-by-S. mutans interaction on dental caries. Genome-wide association analyses were conducted in 709 US children (<13 years old), using the dbGap database acquired from the center for oral health research in appalachia (COHRA) and the Iowa Head Start programmes (GEIRS). A generalized estimating equation was used to examine the gene-by-S. mutans interaction effects on the outcomes (decayed and missing/filled primary teeth due to caries). Sequentially, the COHRA and GEIRS data were used to identify potential interactions and replicate the findings. Three loci at the genes interleukin 32 (IL32), galactokinase 2 (GALK2), and CUGBP, Elav-like family member 4 (CELF4) were linked to S. mutans carriage, and there was a severity of caries at a suggestive significance level among COHRA children (P < 9 × 10), and at a nominal significance level among GEIRS children (P = 0.047-0.001). The genetic risk score that combined the three loci also significantly interacted with S. mutans (P < 0.000 1). Functional analyses indicated that the identified genes are involved in the host immune response, galactose carbohydrate metabolism, and food-rewarding system, which could potentially be used to identify children at high risk for caries and to develop personalized caries prevention strategies.
Adolescent ; Child ; DMF Index ; Dental Caries ; microbiology ; Dental Caries Susceptibility ; genetics ; Galactokinase ; Genome-Wide Association Study ; Humans ; Streptococcus mutans ; genetics ; isolation & purification ; Tooth, Deciduous

OBJECTIVETo observe the dynamic changes of membrane-bound proton-translocating ATPase (F-ATPase) in the development of dental caries, the expression of Streptococcus mutans F-ATPase under different pH concentrations and during the development of dental caries is analyzed.

METHODSStreptococcus mutans cultured under different pH (pH4.0-7.0) concentrations and containing 5% glucose and no glucose containing BHI were collected. RNA was extracted. Subsequently, F-ATPase gene was detected using real-time polymerase chain reaction. Male Wistar rats were divided randomly into caries group and control group. The rats in the caries group were fed caries feed and 5% glucose water, whereas those of control group were fed normal feed. Total RNA was extracted from plaque samples, which were collected from rats' oral cavity every two weeks. F-ATPase gene was detected by real-time PCR. In the 11th week, the upper and lower jaw bone specimens of rats were taken, and molar caries damage assessed.

RESULTSThe expression of F-ATPase in the caries group was higher than that in the control group (P<0.05). In addition, the gene was expressed highest in pH5.0 and the lowest in pH4.0 (P<0.05). 2) The expression of F-ATPase progressively increased during the caries development in both groups; expression in the caries group was higher than that in control group (P<0.05).

CONCLUSIONAcid-resisting viru-lence factor F-ATPase is related closely with the incidence and development of dental caries.

Adenosine Triphosphatases ; metabolism ; Animals ; Dental Caries ; metabolism ; microbiology ; Dental Plaque ; microbiology ; Male ; Protons ; Random Allocation ; Rats ; Rats, Wistar ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans ; drug effects ; genetics ; Virulence Factors

The levels of Streptococcus (S.) mutans infections in saliva were evaluated and a comparison for specific antibody levels among children with different levels of S. mutans infection was made. The promising epitopic regions of antigen AgI/II (PAc) and glucosyltransferase (GTF) for potential vaccine targets related to S. mutans adherence were screened. A total of 94 children aged 3-4 years were randomly selected, including 53 caries-negative and 41 caries-positive children. The values of S. mutans and those of salivary total secretory immunoglobulin A (sIgA), anti-PAc and anti-Glucan binding domain (anti-GLU) were compared to determine the correlation among them. It was found the level of s-IgA against specific antigens did not increase with increasing severity of S. mutans infection, and the complete amino acid sequence of PAc and GTFB was analyzed using the DNAStar Protean system for developing specific anti-caries vaccines related to S. mutans adherence. A significantly positive correlation between the amount of S. mutans and children decayed, missing, and filled teeth index was observed. No significant difference was detected in specific sIgA against PAc or GLU between any two groups. No significant correlation was found between such specific sIgA and caries index. A total of 16 peptides from PAc as well as 13 peptides from GTFB were chosen for further investigation. S. mutans colonization contributed to early children caries as an important etiological factor. The level of sIgA against specific antigens did not increase with increasing severity of S. mutans infection in children. The epitopes of PAc and GTF have been screened to develop the peptide-based or protein-based anti-caries vaccines.
Antibodies, Bacterial ; biosynthesis ; Antigens, Bacterial ; chemistry ; immunology ; Bacterial Proteins ; chemistry ; immunology ; Case-Control Studies ; Child, Preschool ; Dental Caries ; immunology ; pathology ; prevention & control ; Epitopes ; chemistry ; immunology ; Female ; Glucosyltransferases ; chemistry ; immunology ; Humans ; Immunoglobulin A, Secretory ; biosynthesis ; Male ; Peptides ; chemistry ; immunology ; Saliva ; chemistry ; microbiology ; Severity of Illness Index ; Streptococcal Vaccines ; biosynthesis ; chemistry ; immunology ; Streptococcus mutans ; chemistry ; immunology ; pathogenicity ; Vaccines, Subunit ; Virulence Factors ; chemistry ; immunology

OBJECTIVETo analyze the whole microbial structure in a case of rampant caries to provide evidence for its prevention and treatment.

METHODSClinical samples including blood, supragingival plaque, plaque in the caries cavity, saliva, and mucosal swabs were collected with the patient's consent. The blood sample was sent for routine immune test, and the others samples were stained using Gram method and cultured for identifying colonies and 16S rRNA sequencing. DNA was extracted from the samples and tested for the main cariogenic bacterium (Streptococcus mutans) with qPCR, and the whole microbial structure was analyzed using DGGE.

RESULTSThe patient had a high levels of IgE and segmented neutrophils in his blood. Streptococci with extremely long chains were found in the saliva samples under microscope. Culture of the samples revealed the highest bacterial concentration in the saliva. The relative content of hemolytic bacterium was detected in the samples, the highest in the caries cavity; C. albicans was the highest in the dental plaque. In addition, 33 bacterial colonies were identified by VITEK system and 16S rDNA sequence phylogenetic analysis, and among them streptococci and Leptotrichia wade were enriched in the dental plaque sample, Streptococcus mutans, Fusobacterium nucleatum, and Streptococcus tigurinus in the caries cavity, and Lactobacillus in the saliva. S. mutans was significantly abundant in the mucosal swabs, saliva and plaque samples of the caries cavity as shown by qPCR. Compared to samples collected from a healthy individual and another two patients with rampant caries, the samples from this case showed a decreased bacterial diversity and increased bacterial abundance shown by PCR-DGGE profiling, and multiple Leptotrichia sp. were detected by gel sequencing.

CONCLUSIONThe outgrowth of such pathogenic microorganisms as S. mutans and Leptotrichia sp., and dysbiosis of oral microbial community might contribute to the pathogenesis of rampant caries in this case.

Abnormalities, Multiple ; Dental Caries ; microbiology ; Dental Plaque ; microbiology ; Fusobacterium ; isolation & purification ; Humans ; Immunoglobulin E ; blood ; Lactobacillus ; isolation & purification ; Leptotrichia ; isolation & purification ; Limb Deformities, Congenital ; Microbiota ; Mouth Mucosa ; microbiology ; Neutrophils ; cytology ; Phylogeny ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S ; genetics ; Saliva ; microbiology ; Streptococcus ; isolation & purification ; Tooth Abnormalities

OBJECTIVETo explore the relationship between the prevalence of Candida albicans and early childhood caries(ECC) among 3-5 years old children of Uygur and Han nationalities in Kashi city, Xinjiang province.

METHODSTotally 397 generally healthy children(Uyghurs 256, Hans141) aged 3-5 years were recruited randomly in Kashi city using the stratified cluster random method. Dental plaque samples were collected from carious tooth tissues of children with ECC and from supragingival tooth sites of caries free(CF) children, respectively. Plaque samples were cultured and Candida albicans were isolated selectively by using CHROM agar candida medium. The isolates were further identified using methods of germ tubes test, Gram stain and PCR molecular biology. The data were analyzed using Pearson χ(2) test and Spearman analysis.

RESULTSThe prevalenses of Candida albicans were 44.5% (114/256) in Han children and 31.2%(44/141) in Urgur children, respectively(P=0.009). Candida albicans could be isolated from 48.8% (124/254) of ECC children, while 23.8% (34/143) of CF ones(P=0.000). The frequencies of Candida albicans acquisition of boys and girls of Uygur children were 51.2%(66/129) and 37.8%(48/127), respectively (P=0.031). The frequencies of Candida albicans acquisition increased with the decayed missing filled tooth (dmft) scores. For both Uygur and Hanchildren, the detection rates of Candida albicans were correlated with dmft scores(Uygur r=0.350, P=0.001; Han r=0.276, P=0.000).

CONCLUSIONSThe oral Candida albicans distributions were different in Uygur and Han ethnic groups. There were significant correlations between the presence of Candida albicans and ECC severityas well as score of dmft. There was a difference of the Candida albicans distributions between boys and girls among Uygur children. Candida albicans might be one of the important cariogenic microorganisms in ECC.

Candida albicans ; isolation & purification ; Candidiasis ; epidemiology ; Child, Preschool ; China ; epidemiology ; Dental Care ; Dental Caries ; epidemiology ; microbiology ; Dental Plaque ; epidemiology ; microbiology ; Ethnic Groups ; statistics & numerical data ; Female ; Humans ; Male ; Prevalence

OBJECTIVETo analyze the differences between the bacterial diversities in the saliva of caries-free and caries-susceptible adolescents through polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE).

METHODSTwenty adolescent subjects aged 12-18 years were recruited and subdivided into two groups: caries-free adolescents (n = 10) and caries-susceptible adolescents (n = 10). Saliva samples were collected. Total DNA was isolated directly from each sample. A portion of the 16S rRNA gene locus was PCR-amplified by using universal primers. Microbial diversity was analyzed through PCR-DGGE.

RESULTSAnalyzing the DGGE profile, we found that the composition of the saliva microbiome exhibited great intra-individual differences; the average band numbers of the caries-free adolescent group and the caries-susceptible adolescent group were 32.5 ± 3.7 and 27.3 ± 3.4, respectively. The differences between the groups were statistically significant (P = 0.008). Shannon-Wiener's indexes of the caries-susceptible adolescent group and the caries-free adolescent group were 2.5 ± 0.2 and 2.6 ± 0.2, respectively, but the differences between the groups were not significant (P = 0.405). Clustering analysis results suggested that most of the samples in the same group clustered together; this observation showed a high community structure similarity.

CONCLUSIONThe microbial diversity and complexity of bacteria in saliva are significantly higher in caries-free adolescents than in caries-susceptible adolescents. During caries development, bacterial diversity in the saliva likely decreases.

Adolescent ; Bacteria ; Child ; DNA, Bacterial ; analysis ; Denaturing Gradient Gel Electrophoresis ; Dental Caries ; microbiology ; Dental Caries Susceptibility ; Humans ; Microbiota ; Mouth ; microbiology ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S ; Saliva ; microbiology

A human oral microbiota is the ecological community of commensal, symbiotic, and pathogenic microorganisms found in human oral cavity. Oral microbiota exists mostly in the form of a biofilm and maintains a dynamic ecological equilibrium with the host body. However, the disturbance of this ecological balance inevitably causes oral infectious diseases, such as dental caries, apical periodontitis, periodontal diseases, pericoronitis, and craniofacial bone osteomyelitis. Oral microbiota is also correlated with many systemic diseases, including cancer, diabetes mellitus, rheumatoid arthritis, cardiovascular diseases, and preterm birth. Hence, oral microbiota has been considered as a potential biomarker of human diseases. The "Human Microbiome Project" and other metagenomic projects worldwide have advanced our knowledge of the human oral microbiota. The integration of these metadata has been the frontier of oral microbiology to improve clinical translation. By reviewing recent progress on studies involving oral microbiota-related oral and systemic diseases, we aimed to propose the essential role of oral microbiota in the prediction of the onset, progression, and prognosis of oral and systemic diseases. An oral microbiota-based prediction model helps develop a new paradigm of personalized medicine and benefits the human health in the post-metagenomics era.
Biomarkers ; Cardiovascular Diseases ; microbiology ; Dental Caries ; microbiology ; Diabetes Mellitus ; microbiology ; Humans ; Metagenomics ; Microbiota ; Mouth ; microbiology ; Mouth Diseases ; microbiology ; Neoplasms ; microbiology ; Oral Health ; Periodontal Diseases ; microbiology