Biofilms ; Dental Caries ; microbiology ; Humans ; Proteome ; metabolism

China ; Dental Caries ; microbiology ; prevention & control ; Humans

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

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*

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

OBJECTIVETo study dynamic relation between periodontal pathogens and cariogenic bacteria under analogous oral environment.

METHODSEight periodontopathic and cariogenic bacteria of Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Provotella intermedium (Pi), Streptococcus mutans (Sm), Streptococcus sanguis (Ss), Actinomyces viscosus (Av) and Lactobacillus acidophilus (La) were used. These eight strains were cultured in modified chemostat under analogous oral environment which contained 600 ml modified BM medium supplemented with 2.5 g/L porcine gastric mucin, respectively. After 1, 24, 48 and 96 h, optical sectioning of plaque biofilms on removable and replaceable hydroxyapatite disks was analyzed by the combination of live bacterial Gram fluorescence staining and confocal laser scanning microscopy. Biofilm thickness and reconstruction of the three-dimensional architecture of plaque biofilms were made.

RESULTSBiofilm thickness increased significantly with time (P < 0.001). Biofilms of Aa were thinner than those of Ss and eight-specie biofilms were thicker than those formed by Ss and Aa per time point. Three-dimensional images showed periodontal pathogens mainly occurred in cariogenic bacterial complex or on the biofilm surface.

CONCLUSIONSGram-positive cariogenic species initially predominated in artificial plaque, followed by the increasing proportions of Gram-negative periodontal pathogens. The relation between microecological balance among bacteria and diseases is worthy of further studies.

Bacteria ; growth & development ; Biofilms ; Dental Caries ; microbiology ; Ecology ; Humans ; Microscopy, Confocal ; Periodontal Diseases ; 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

OBJECTIVETo investigate the initial colonization of Mutans streptococci (MS) on teeth of children.

METHODSDental plaque was collected from 123 children aged from 7 to 42 months. MS was isolated by culturing on selective medium and identified by biochemical tests.

RESULTSMS was detected in 51 of 123 children. The rate of colonization was 41.5%, and the mean age of colonization was 29 month. The incidence of MS infection increased with age and tooth eruption, and reached peak at 25 - 31 months, which was statistically significant. There was a correlation between infection of MS and dental caries.

CONCLUSIONThe results indicate that the susceptive period of MS infection is from 25 to 31 months when the second primary molars erupt. MS infection is associated with dental caries.

Age Factors ; Child, Preschool ; Dental Caries ; microbiology ; Dental Plaque ; microbiology ; Female ; Humans ; Infant ; Male ; Streptococcus mutans ; growth & development ; Tooth Eruption

OBJECTIVETo compare the production of organic acid of different genotype Streptococcus mutans (S. mutans) isolated from children with different caries experience.

METHODS66 strains of S.mutans isolated from dental plaques of children aged from 3 to 5 with different caries experience were chosen as test bacteria. The quantities of organic acid include formic acid, acetic acid and lactic acid which produced by different genotype of S. mutans, were measured by gas chromatograph.

RESULTSThere were significant difference in production of organic acid among the different genotypes of S. mutans isolated from children with different caries susceptibility, and so were the strains isolated from children within the same caries susceptibility (P < 0.05). The more genotypes the strain had, the more organic acid it produced (P < 0.05). Among all the organic acid, the quantity of lactic acid was much more than that of formic acid and acetic acid.

CONCLUSIONSThere were significant difference in the ability of the strains with different genotypes to produce organic acid, and the more genotypes it has, the more organic acid it produced.

Carboxylic Acids ; metabolism ; Child, Preschool ; Dental Caries ; microbiology ; Dental Plaque ; microbiology ; Genotype ; Humans ; Streptococcus mutans ; genetics ; metabolism

OBJECTIVETo preliminarily investigate the relationship between the Lactate dehydrogenase (LDH) activity of Streptococcus mutans (S. mutans) and dental caries initiation.

METHODS100 S. mutans strains derived from caries-active and caries-free individuals were cultured in BHI medium supplemented with glucose. Cells were extracted and ruptured, and the extracted liquid protein was quantified with Coomassie brilliant blue G250 staining methods. LDH activity was assayed using the pyruvate-dependent oxidation of NADH-with and without FDP.

RESULTSLDH activity of the two groups strains had no difference (P > 0.05), but the distribution of differ class enzyme activity strains in the two groups was different (P < 0.05).

CONCLUSIONLDH activity of S. mutans is correlated to the initiation of dental caries to some extent. The measurement methods in this study can be applied in preliminary quantitation of LDH activity and the screening of S. mutans strains.

Case-Control Studies ; Dental Caries ; microbiology ; Humans ; Lactate Dehydrogenases ; Oxidation-Reduction ; Streptococcus mutans ; metabolism