OBJECTIVEThe study is to investigate the microbial composition of interdental and subgingival plaques of periodontitis patients with or without malodor, to explore the relationships between periodontitis and oral malodor.

METHODS20 patients of periodontitis with malodor were chosen from 210 patients of periodontitis, and the clinical parameter of plaque index (PLI), gingival bleeding index (GBI) and probing depth (PD) were measured and compared with the control group which had periodontal disease without malodor. During the experiment, the interdental and subgingival microbial samples in both groups were collected and sent to anaerobic culture for 48 hrs, then the total CFU/ml of each sample were counted, and each type of bacteria was separated and identified. All of the data were analyzed by using the statistical software SPSS 10.0.

RESULTS(1) There were no satistical differences on PLI, GBI, PD between experimental group and control group. (2) The percents of leptospira in both interdental and subgingival plaques of test group were significantly higher than that of the control group (P < 0.01). (3) Either the interdental or in subgingival plaques, the count results of CFU/ml were similar in both groups (P > 0.05). (4) The proportions of malodor producing anaerobic bacteria in interdental gingival plaque, such as P. gingivalis and Veillonelia, were singnificantly different between test group and control group.

CONCLUSIONThe proportions of VSC's producing anaerobic bacteria in interdental gingival plaque may be play the significant roles in oral malodor. Further studies should be taken to elucidate the relationship between malodor and periodontitis.

Bacteria, Anaerobic ; classification ; Dental Plaque ; microbiology ; pathology ; Dental Plaque Index ; Gingiva ; microbiology ; pathology ; Halitosis ; microbiology ; Humans ; Odorants ; Periodontitis ; microbiology ; pathology

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 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

BACKGROUND: About half of the world population is infected with H. pylori, but the transmission and the source of this infection are still unclear. Recently, dental plaque (DP) and saliva have been implicated as possible sources of H. pylori infection. This study was done to investigate the detection rates of H. pylori in the DP and saliva by use of PCR depending on H. pylori infection state of gastric mucosa. METHODS: In 46 subjects, gastric H. pylori colonization was evaluated with CLO test, microscopy of Gram stained mucosal smear, culture and histology after modified Giemsa staining in the antrum and body, respectively. A patient was regarded as H. pylori positive if one or more of the four aforementioned test methods demonstrated H. pylori colonization of the gastric mucosa. For detection of H. pylori in the DP and saliva, PCR assay was done with ET4-U and ET4-L primers. To estimate the sensitivity and specificity of this PCR, H. pylori positivity was evaluated in the antrum and body, separately. RESULTS: The sensitivity of mucosal PCR was 50.0% (27/54) and the specificity 86.8% (33/38). When a subject was regarded as H. pyloi positive, if either antrum or body mucosal H. pylori was is positive, the positive rate of mucosal PCR was 62.1% (18 subjects) in the 29 H. pylori-positive and 17.6% (3 subjects) in the 17 H. pylori-negative subjects. DP PCR was positive in 2 of 29 H. pylori-positive subjects (6.9%) and none in the 17 H. pylori-negative (0%). Saliva PCR was positive in 4 of 14 H. pylori-positive subjects (28.6%) and none of 6 H. pylori-negative (0%). CONCLUSION: The detection rates of H. pylori in DP and saliva by PCR were rather low, 6.9% and 28.6%, respectively, and these rates might have been underestimated by low sensitivity of the PCR method used in this study. However, the results that H. pylori was found in the DP and saliva suggest that the oral cavity can perform a role as a reservoir of H. pylori in Korea.
Dental Plaque/microbiology* ; Gastric Mucosa/microbiology ; Helicobacter pylori/isolation & purification* ; Human ; Polymerase Chain Reaction ; Saliva/microbiology* ; Sensitivity and Specificity

The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial composition in subgingival plaque suggest that nitrate-reducing bacteria are associated with periodontal health, but the impact of periodontitis on nitrate-reducing capacity (NRC) and, therefore, nitric oxide availability has not been evaluated. The current study aimed to evaluate how periodontitis affects the NRC of the oral microbiota. First, 16S rRNA sequencing data from five different countries were analyzed, revealing that nitrate-reducing bacteria were significantly lower in subgingival plaque of periodontitis patients compared with healthy individuals (P < 0.05 in all five datasets with n = 20-82 samples per dataset). Secondly, subgingival plaque, saliva, and plasma samples were obtained from 42 periodontitis patients before and after periodontal treatment. The oral NRC was determined in vitro by incubating saliva with 8 mmol/L nitrate (a concentration found in saliva after nitrate-rich vegetable intake) and compared with the NRC of 15 healthy individuals. Salivary NRC was found to be diminished in periodontal patients before treatment (P < 0.05) but recovered to healthy levels 90 days post-treatment. Additionally, the subgingival levels of nitrate-reducing bacteria increased after treatment and correlated negatively with periodontitis-associated bacteria (P < 0.01). No significant effect of periodontal treatment on the baseline saliva and plasma nitrate and nitrite levels was found, indicating that differences in the NRC may only be revealed after nitrate intake. Our results suggest that an impaired NRC in periodontitis could limit dietary nitrate-derived nitric oxide levels, and the effect on systemic health should be explored in future studies.
Humans ; Nitrates ; Nitric Oxide ; Nitrites ; RNA, Ribosomal, 16S/genetics* ; Periodontitis/microbiology* ; Bacteria ; Dental Plaque/microbiology* ; Saliva/microbiology* ; Microbiota/genetics*

OBJECTIVETo examine the spatial distribution of dead and vital bacteria in the early formation of native dental biofilm.

METHODSAn experimental dental biofilm model in the oral cavity was established by enamel slabs and the spatial distribution of dead and vital bacteria in the early colonization of native dental biofilm on the enamel surface was observed by in situ real-time and dynamic observations and optical sections utilizing confocal laser scanning microscope (CLSM) and live and dead bacterial fluorescence staining technique.

RESULTSAt the initial stage of dental biofilm formation, the structure was sparse and the percentage of dead cells reached 70% - 80% at the inner layers. In the middle layers the structure became denser than in the inner layers, which was mainly composed of vital cells (40% - 70%), and void-like structures were surrounded by vital bacteria. In the outer layers, the structure was sparse and vital cells occupied 20% - 40%.

CONCLUSIONSNative dental biofilms showed an uneven spatial distribution of vital and dead microorganisms. The percentage of vital microorganisms was lower adjacent to the enamel surface, increased in the z-axis towards the central parts, and decreased again towards the outer layers. The dead bacteria is an integral component in the early formation of native dental biofilm. Bacteria in the biofilms increased with time forming abundant channels.

Adult ; Biofilms ; Dental Plaque ; microbiology ; Humans ; Microscopy, Confocal ; Staining and Labeling ; Young Adult

OBJECTIVETo establish a systematic method for isolation and identification of aerobic and facultative anaerobic bacteria in the oral cavity.

METHODSSamples of the saliva, dental plaque and periapical granulation tissue were collected from 20 subjects with healthy oral condition and from 8 patients with different oral diseases. The bacteria in the samples were identified by morphological identification, VITEK automatic microorganism identification and 16s rRNA gene sequencing.

RESULTSVITEK automatic microorganism identification and 16s rRNA gene sequencing showed an agreement rate of 22.39% in identifying the bacteria in the samples. We identified altogether 63 bacterial genus (175 species), among which Streptococcus, Actinomyces and Staphylococcus were the most common bacterial genus, and Streptococcus anginosus, Actinomyces oris, Streptococcus mutans and Streptococcus mitis were the most common species. Streptococcus anginosus was commonly found in patients with chronic periapical periodontitis. Streptococcus intermedius and Staphylococcus aureus were common in patients with radiation caries, and in patients with rampant caries, Streptococcus mutans was found at considerably higher rate than other species.

CONCLUSIONAerobic and facultative anaerobic bacteria are commonly found in the oral cavity, and most of them are gram-positive. 16s rRNA gene sequencing is more accurate than VITEK automatic microorganism identification in identifying the bacteria.

Actinomyces ; isolation & purification ; Dental Caries ; Dental Plaque ; microbiology ; Humans ; Mouth ; microbiology ; RNA, Ribosomal, 16S ; genetics ; Saliva ; microbiology ; Staphylococcus aureus ; isolation & purification ; Streptococcus ; isolation & purification

OBJECTIVETo evaluate the dynamic changes of Streptococcus mutans concentration of plaque during fixed appliance treatment and the effects of two materials of ligation on Streptococcus mutans concentration.

METHODSTwenty-eight patients undergoing fixed appliance treatment were observed. Ligature wire and elastomeric rings were applied on one side of arches, stochastically. The dynamic changes on the quantity and percentage of Streptococcus mutans were observed before and after fixed appliance bonding.

RESULTSStatistically significant increase of the quantity and percentage of Streptococcus mutans was found after fixed appliance bonding, and the percentage of Streptococcus mutans in the plaque around the brackets ligated with elastomeric rings was more than that of ligature wire at the beginning of fixed appliance bonding, statistically.

CONCLUSIONSThe finding suggested that the caries-associated capability of the plaque increased after bonding and there was greater caries-associated capability of the plague on the teeth when elastomeric rings was used than that of the plague when ligature wire was used at treatment beginning. The ligature wire is recommended in the fixed appliance treatment.

Adolescent ; Bacterial Adhesion ; Child ; Colony Count, Microbial ; Dental Caries ; prevention & control ; Dental Plaque ; microbiology ; Female ; Humans ; Male ; Orthodontic Appliances ; microbiology ; Orthodontic Brackets ; microbiology ; Streptococcus mutans ; physiology

OBJECTIVETo assess the prevalence of specific kgp genotypes in puberty gingivitis and investigate their possible association with disease severity.

METHODSSubgingival plaque samples were collected from 72 pubertal children aged from 14 to 17 years, which were divided into two groups, gingivitis group and healthy (control) group. Clinical parameters were recorded beforehand. PCR technique was used to amplify the region encoding the catalytic domain of gingipain K (KGP). The PCR products were digested with restriction enzymes Mse I.

RESULTSThe kgp-A genotype was digested in fragments of 102 bp, 288 bp and 402 bp, and kgp-B genotype was unrestricted with 792 bp. Virulent strain P. gingivalis W83 was manifested by kgp-A genotype while a virulent strain P. gingivalis ATCC 33277 was manifested by kgp-B genotype. All P. gingivalis positive subjects were subgingivally colonized by only one kgp genotype. The prevalence of kgp-A genotype in puberty gingivitis group and gingival healthy group was 79.0% and 22.2% respectively. The distribution differences of genotypes between the two groups were statistically different (P = 0.028). There was no statistically significant difference in the clinical parameters between pubertal subjects harboring P. gingivalis of kgp-A genotype and kgp-B genotype (P > 0.05).

CONCLUSIONSMost subjects with puberty gingivitis were harbored by the same kgp genotype as that of virulent strain P. gingivalis W83. It may be necessary to continue to monitor individuals who are positive for P. gingivalis of kgp-A genotype since their risk of developing periodontal diseases may be increased in the future.

Adolescent ; Case-Control Studies ; Dental Plaque ; microbiology ; Female ; Genotype ; Gingivitis ; microbiology ; Humans ; Male ; Polymerase Chain Reaction ; Porphyromonas gingivalis ; genetics

OBJECTIVETo analyze horizontal transmission patterns of Streptococcus mutans among caries-active preschool children for early interventions of dental caries.

METHODSPlaque samples obtained from 20 caries-active preschool children between 4 and 5 years of age were cultured under anaerobic conditions for isolating S. mutans, which were identified by morphological and biochemical analyses and PCR using primers homologous to the surface protein glucosyltransferase B (gtfB). The genotypes of the isolated S. mutans strains were determined by arbitrarily primed PCR (AP-PCR).

RESULTSOf the 200 S. mutans isolates obtained, 19 were excluded by biochemical analysis, and the remaining 181 isolates were identified as S. mutans by PCR with primers of gtfB, showing 37 different genotypes as identified by AP-PCR. Six children were found to carry S. mutans of a single genotype, 11 carried 2 genotypes, 2 had 3 genotypes, and 1 had 4 genotypes; 2 children from different classes were found to carry S. mutans of the same single genotype.

CONCLUSIONWe identified 37 genotypes of S. mutans in these caries-active preschool children, among whom horizontal transmissions of the strains were not found.

Child, Preschool ; Dental Caries ; microbiology ; Dental Plaque ; Genotype ; Glucosyltransferases ; Humans ; Polymerase Chain Reaction ; Streptococcal Infections ; transmission ; Streptococcus mutans ; classification