Periodontal Bacterial Species Research Articles

Periodontal bacterial species and target serotypes in individuals harboring Aggregatibacter actinomycetemcomitans: a retrospective study in a large Brazilian population

OBJECTIVE: The first aim of this study was to evaluate the prevalence of A. actinomycetemcomitans in a large Brazilian population. The second aim was to analyse the frequency of A. actinomycetemcomitans serotypes, P. gingivalis, P. intermedia, T. forsythia and C. rectus in the positive individuals for A. actinomycetemcomitans. MATERIAL AND METHODS: The population was composed of 1,320 individuals. Subgingival biofilm samples were taken for molecular analysis. RESULTS: It was revealed that 263 (19.9%) individuals tested positive for A. actinomycetemcomitans. Then, the genomic DNA of A. actinomycetemcomitans serotypes (a to f ) as well as P. gingivalis, P. intermedia, T. forsythia, and C. rectus were analysed. A. actinomycetemcomitans serotype a was detected in 28.5%, serotype b in 15.97%, serotype c in 51.71%, and serotype e in 3.80% of individuals, respectively. Serotypes d and f were not detected. The frequency of A. actinomycetemcomitans serotype a was significantly higher in C. rectus-positive individuals than in P. gingivalis-, P. intermedia-, or T. forsythia-positive individuals. Additionally, the frequency of serotypes b and c were significantly higher in both C. rectus- and T. forsythia-positive individuals in comparison to P. gingivalis- and P. intermedia-positive individuals. Meanwhile, the frequency of serotype e was not associated with the presence of the other periodontal pathogens. CONCLUSION: The data of this large population confirmed A. actinomycetemcomitans prevalence values previously observed in smaller groups. Further, suggested potential coaggregation among selected A. actinomycetemcomitans serotypes and other target periodontal bacterial species in the subgingival environment.

Comparison of three qPCR-based commercial tests for detection of periodontal pathogens

In periodontal practice microbial results of periodontal test kits for identification of key pathogens are an aid in the treatment planning. Information on the performance of commercially available test kits is therefore essential for the clinician. In this retrospective analysis three commercially available qPCR kits for detection and quantification of selected periodontal bacterial species were compared, using 100 clinical samples from patients with untreated periodontitis. The analysis involved two separate comparisons in which kit A (LabOral Diagnostics, The Netherlands) was compared with kit B (Advanced Dental Diagnostics, The Netherlands), and with kit C (OralDent diagnostics, The Netherlands). Analytic procedures for detection and quantification of selected periodontal bacterial species were carried out according to the instructions of the laboratories. Kit A detected target species more often, and absolute numbers of bacterial cells were higher than with kit B. A high degree of similarity was found between the test outcomes by kit A and kit C. All three kits performed satisfactory but small and significant differences exist between kits.

Effect of Hydrogen Peroxide Photoactivated Decontamination Using 940 nm Diode Laser in Periodontal Treatment: A Pilot Study.

Objective: The aim of this study was to compare the antimicrobial effects of hydroxyl radical generation by photoactivation of hydrogen peroxide (H2O2) with diode laser (λ = 940 nm) in combination with conventional nonsurgical periodontal therapy. Materials and methods: Thirty-eight patients and 114 teeth were included in this study. The test teeth were randomly assigned to one of the three treatment groups: Group 1 (control group): scaling and root planning (SRP); and the following experimental groups: Group 2: SRP +940 nm diode laser; Group 3: SRP+photoactivation of H2O2 with 940 nm diode laser. Clinical examinations, such as periodontal probing depth (PPD), clinical attachment level (CAL), and bleeding on probing (BoP) were performed before and after the treatment. The microbiological evaluation included nine periodontal bacterial species investigated by means of real-time polymerase chain reaction assay before and after the treatment. The clinical and bacterial differences were assessed between the investigated groups. Results: The total bacteria load was reduced for all three studied groups and all periodontal indexes (PPD, CAL, and BoP) were improved after each treatment. Group 3 showed significant bacterial reduction of the major periodontal bacteria such as Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Peptostreptococcus micros, Fusobacterium nucleatum, Eubacterium nodatum (p < 0.001) in contrast to the other two groups (p > 0.001). Differences between tested groups showed significant results with regard to Group 3. Conclusions: The synergistic effect of SRP and photoactivation of H2O2 with 940 nm diode laser offers an efficient and reliable antimicrobial effect in the nonsurgical periodontal treatment approach.

An oral health optimized diet reduces the load of potential cariogenic and periodontal bacterial species in the supragingival oral plaque: A randomized controlled pilot study

This study aimed to investigate the effects of an oral health optimized diet on the composition of the supragingival oral plaque in a randomized controlled trial. Participants of the standard diet group (n = 5) had a diet high in processed carbohydrates and did not change their dietary behavior during the observation. The healthy diet group (n = 9) had to change the diet after 2 weeks from a diet high in processed carbohydrates to a diet low in carbohydrates, rich in omega‐3 fatty acids, rich in vitamins C and D, antioxidants and fiber for 4 weeks. Saliva and supragingival plaque samples were taken at the end of week two and eight of the observation period to investigate the composition of microbiota in saliva and supragingival plaque. Data were subjected to an exploratory analysis to identify significant differences. Statistically significant differences were only found in the healthy diet group between the baseline (week 2) and the final sample (week 8) for specific species in plaque and saliva samples. A reduction of the total counts of Streptococcus mitis group, Granulicatella adiacens, Actinomyces spp., and Fusobacterium spp. was found in plaque samples of the healthy diet group. In saliva samples of the healthy diet group, the total counts of Actinomyces spp. and Capnocytophaga spp. decreased. A diet low in carbohydrates, rich in omega‐3 fatty acids, rich in vitamins C and D, and rich in fiber reduced Streptococcus mitis group, Granulicatella adiacens, Actinomyces spp., and Fusobacterium spp. in the supragingival plaque.

Bacterial supernatants elevate glucose-dependent insulin secretion in rat pancreatic INS-1 line and islet \u03b2-cells via PI3K/AKT signaling

Diabetes and periodontitis are considered associated chronic diseases, and hyperinsulinemia in prediabetes has been shown to be present in normoglycemic animals with periodontitis. As periodontal bacterial species are significant sources of endotoxemia and may directly stimulate insulin secretion, we hypothesized that increased bacterial virulence may exert an adverse effect on rat pancreatic β-cell function via PI3K/AKT signaling. INS-1 cells and isolated pancreatic islets were cultured separately with the following supernatants: Streptococcus anginosus, Streptococcus mutans, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis (P.g), and Treponema denticola (T.d). Supernatants were purified from single bacterial cultures and prepared at different dilutions (100 pg/ml, 50 ng/ml, 200 ng/ml, and 500 ng/ml) to challenge INS-1 and islets. Gene expression (IL-1β, TNFα, IL-6, TLR2, TLR4, Ins1, and Ins2) and insulin secretion were measured. The results showed upregulation of gene expression up to 5.5-fold, not only as a result of the different dilutions used, but also due to bacterial virulence (p < 0.05). P.g and T.d supernatants demonstrated an increase in insulin secretion to fivefold at hypo- and hyperglycemia, yet stimulation from hypo- to hyperglycemia stays in the same ratio. Activation of TLR4/PI3K/AKT signaling by supernatants in INS-1 cells resulted in increased IL-1β, TNFα, IL-6 gene expression levels, and AKT phosphorylation, which were abolished by TLR4 and PI3K/AKT signaling inhibitor. We demonstrated that bacterial supernatants derived from gram-negative species increasingly stimulate insulin secretion in β-cells and TLR4 may promote inflammation by activating the PI3K/AKT signaling pathway to induce pro-inflammatory molecules. Bacterial species, depending on their virulence, appear to play a role in the relationship between periodontitis and prediabetes by promoting insulin resistance and β-cell compensatory response.

Impact of Docosahexaenoic Acid Therapy on Subgingival Plaque Microbiota.

Oral docosahexaenoic acid (DHA) + aspirin therapy has been shown to reduce periodontal probing depth (PD) and local inflammatory mediators in gingival crevicular fluid (GCF) among patients with untreated chronic periodontal disease. Whether DHA + aspirin therapy influences specific bacterial burden in this setting is unknown. Thus, the aim of this study is to evaluate the impact of DHA with low-dose aspirin therapy on periodontal bacterial profile in patients with periodontitis. Fifty-five adults with moderate-to-severe periodontitis were enrolled in a randomized, 3-month double-masked, placebo-controlled trial of daily 2 g DHA or placebo capsules enriched with 81 mg aspirin; 46 enrollees completed the trial. In addition to clinical measurements and GCF sampling, subgingival plaque samples were collected from four posterior sites in all participants and analyzed by the checkerboard DNA-DNA hybridization technique. Presence of 40 periodontal bacterial species at baseline and 3 months was semiquantitatively estimated. Despite broad improvements in clinical parameters, total bacteria and individual species counts in dental plaque did not differ significantly between baseline and 3 months in either group (P >0.1 for all). A modest effect of DHA + aspirin on Porphyromonas gingivalis counts was associated with 14% (95% confidence interval: 3% to 35%) of the observed benefit of DHA on PD. DHA + aspirin had no significant effect on individual plaque bacterial counts in unadjusted models or those adjusted for age, sex, and race (P >0.1 for all). This pilot randomized, controlled trial suggests that DHA + aspirin therapy improves periodontitis largely by modulating host inflammatory response. Changes in individual species levels in subgingival plaque microbiota were not detectable; however, a small portion of the benefit appears to stem from changes in P. gingivalis levels in the DHA + aspirin treatment group. Whether this change in P. gingivalis levels leads to biofilm alteration with reversal of dysbiosis requires further longitudinal and more specific investigations.

Do quaternary ammonium monomers induce drug resistance in cariogenic, endodontic and periodontal bacterial species?

ObjectivesAntibacterial monomers were developed to combat oral biofilm acids and caries; however, little is known on whether quaternary ammonium monomers (QAMs) would induce drug resistance in oral bacteria. The objective of this study was to investigate the effects of new antimicrobial monomers dimethylaminohexadecyl methacrylate (DMAHDM) and dimethylaminododecyl methacrylate (DMADDM) on the induction of drug resistance in eight species of cariogenic, endodontic and periodontal bacteria for the first time. MethodsStreptococcus mutans (S. mutans), Streptococcus sanguis, Streptococcus gordonii, Enterococcus faecalis (E. faecalis), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Fusobacterium nucleatum (F. nucleatum), Porphyromonas gingivalis (P. gingivalis), and Prevotella intermedia (P. intermedia) were tested. Minimum inhibitory concentration (MIC) was assessed using chlorhexidine (CHX) as control. Minimal bactericidal concentration (MBC), bacterial growth and membrane permeability properties were also investigated. ResultsCHX induced drug resistance in four species. DMAHDM did not induce any resistance. DMADDM induced drug resistance in only one benign species S. gordonii. The DMADDM-resistant and CHX-resistant S. gordonii had the same MIC and MBC values as S. gordonii parental strain against DMAHDM (p>0.1), hence DMAHDM effectively inhibited the resistant strains. The resistant strains had slower growth metabolism than parental strain. SignificanceDMAHDM induced no drug resistance, and DMADDM had much less drug resistance than the commonly-used CHX in the eight common oral species. With its potent antimicrobial functions shown previously, the new DMAHDM is promising for applications in restorative, preventive, periodontal and endodontic treatments to combat cariogenic and pathological bacteria with no drug resistance in all tested species.

Characterization of specimens obtained by different sampling methods for evaluation of periodontal bacteria.

Quantitative analysis of periodontal bacteria is considered useful for clinical diagnosis, evaluation and assessment of the risk of periodontal disease. The purpose of this study was to compare the effectiveness of sampling of saliva, supragingival and subgingival plaque for evaluation of periodontal bacteria. From each of 12 subjects, i) subgingival plaque was collected from the deepest pocket using a sterile paper point, ii) stimulated whole saliva was collected after chewing gum, and iii) supragingival plaque was collected using a tooth brush. These samples were sent to the medical examination laboratory for quantitative analysis of the counts of three periodontal bacterial species: Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. The proportions of these bacteria in subgingival plaque were higher than those in saliva or supragingival plaque, but lower in subgingival plaque than in saliva or supragingival plaque. In several cases, periodontal bacteria were below the levels of detection in subgingival plaque. We concluded that samples taken from subgingival plaque may be more useful for evaluating the proportion of periodontal bacteria in deep pockets than is the case for other samples. Therefore, for evaluation of periodontal bacteria, clinicians should consider the characteristics of the specimens obtained using different sampling methods.

Association between periodontitis, periodontopathogens and preterm birth: is it real?

To identify the association between periodontitis and periodontal pathogens with preterm birth despite the strict control of some important confounders, such as infectious processes and criteria for diagnosis of periodontitis during pregnancy. In this cross-sectional study were included 70 healthy puerperal women between 20 and 35years without a history of genitourinary infections during pregnancy. Based on the gestational age they were divided into two groups: 45 with term birth (>37weeks) and 25 with preterm birth (<37weeks). Previous informed consent, a gynecologic and dental history that included gynecologic and obstetric background, periodontal status applying different authors' criteria of periodontitis diagnosis, presence of periodontopathogens, dental caries and oral hygiene were recorded. There was no association between periodontitis, periodontopathogens and preterm birth. There were no statistical differences applying different authors' criteria diagnosis of periodontitis. Gingivitis status was similar, but probing depth was greater in preterm birth subjects, perhaps they are young women, and this finding could be an early sign of periodontitis. In like manner, the main periodontal bacterial species are not associated with preterm birth, general hygiene and care habits are poorer than term birth subjects. We could suggest that preterm birth is a multifactorial condition and the role of periodontitis and the periodontopathogens itself is not sufficient to trigger the preterm birth. There are factors such as infectious processes and diagnostic criteria for periodontitis that could be responsible for controversial results.

Changes in Clinical and Microbiological Periodontal Profiles Relate to Progression of Carotid Intima‐Media Thickness: The Oral Infections and Vascular Disease Epidemiology Study

BackgroundNo prospective studies exist on the relationship between change in periodontal clinical and microbiological status and progression of carotid atherosclerosis.Methods and ResultsThe Oral Infections and Vascular Disease Epidemiology Study examined 420 participants at baseline (68±8 years old) and follow‐up. Over a 3‐year median follow‐up time, clinical probing depth (PD) measurements were made at 75 766 periodontal sites, and 5008 subgingival samples were collected from dentate participants (average of 7 samples/subject per visit over 2 visits) and quantitatively assessed for 11 known periodontal bacterial species by DNA‐DNA checkerboard hybridization. Common carotid artery intima‐medial thickness (CCA‐IMT) was measured using high‐resolution ultrasound. In 2 separate analyses, change in periodontal status (follow‐up to baseline), defined as (1) longitudinal change in the extent of sites with a ≥3‐mm probing depth (Δ%PD≥3) and (2) longitudinal change in the relative predominance of bacteria causative of periodontal disease over other bacteria in the subgingival plaque (Δetiologic dominance), was regressed on longitudinal CCA‐IMT progression adjusting for age, sex, race/ethnicity, diabetes, smoking status, education, body mass index, systolic blood pressure, and low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol. Mean (SE) CCA‐IMT increased during follow‐up by 0.139±0.008 mm. Longitudinal IMT progression attenuated with improvement in clinical or microbial periodontal status. Mean CCA‐IMT progression varied inversely across quartiles of longitudinal improvement in clinical periodontal status (Δ%PD≥3) by 0.18 (0.02), 0.16 (0.01), 0.14 (0.01), and 0.07 (0.01) mm (P for trend<0.0001). Likewise, mean CCA‐IMT increased by 0.20 (0.02), 0.18 (0.02), 0.15 (0.02), and 0.12 (0.02) mm (P<0.0001) across quartiles of longitudinal improvement in periodontal microbial status (Δetiologic dominance).ConclusionLongitudinal improvement in clinical and microbial periodontal status is related to a decreased rate of carotid artery IMT progression at 3‐year average follow‐up.

Characterization of Periodontal Biofilm in Down Syndrome Patients: A Comparative Study

The aim of this study was to characterize the main periodontal bacterial species in Down syndrome (DS) patients with and without periodontitis. This cross-sectional study involved 75 DS patients, 45 with and 30 without periodontitis. Informed consent, health and dental questionnaires and periodontitis diagnosis were performed PCR and LAMP assays were performed on subgingival dental plaque sample. Tannerella forsythia was the most frequent bacteria detected in the group with and without periodontitis (95.5 and 63.3%) followed by Treponema denticola (88.8 and 50%) and Porphyromonas gingivalis (53.3 and 25% respectively). There were statistical differences between groups (p < 0.05). Pg fimA type I was the most frequent Porphyromonas gingivalis genotype. Two different sets of primers (Aa-F/Aa-R and ltx3/ltx4) were used to detect Aggregatibacter actinomycetemcomitans and different frequencies were obtained, (68% and 14.6% respectively), they had a weak correlation (Cohen Kappa = 0.16). After sequencing of PCR products, ltx3/ltx4 showed more specificity. JP2 clone of A. actinomycetemcomitans was not detected in any sample. The composition of oral biofilm is fundamental for the development of periodontal disease independently of immunological alterations associated with DS. The frequency of detection of A. actinomycetemcomitans reported in the literature has a wide range, because the primers and probes applied

Microbial Changes in Subgingival Plaque and Polymicrobial Intracellular Flora in Buccal Cells after Fixed Orthodontic Appliance Therapy: A Preliminary Study

The oral ecosystem is strictly related to a balance maintained by specific niches recognized as sites, where oral bacteria can metabolize avoiding the immune system response. The oral bacteria species that colonize the ecological niches vary during fixed orthodontic treatment, with a prevalence of periodontal bacterial species. Qualitative analysis of five periodontal pathogens was used to investigate the microbial colonization rate in the crevice and buccal epithelial cells. The presence of inadequate oral hygiene was considered as a modulation variable for microbial colonization. Statistical analysis was performed by Fisher's exact test, ANOVA, and Pearson correlation. A P value lower than 0.05 was assumed as statistically significant. Tannerella forsythia was the only periodontal pathogen detected with a statistically admissible frequency. The positivity for Tannerella forsythia was correlated to sampling time and oral hygiene motivation. In buccal epithelial cells, both factors contributed to microbial decrease (P < 0.05), whereas, in crevice, oral hygiene motivation promoted a decrease in the microbial colonization rate (P < 0.05). According to microbiological findings, it is possible to identify how correct motivation for oral hygiene is more than enough to modulate or to avoid an upset of the oral ecosystem balance in early stages of orthodontic treatment.

Retrospective investigation of gingival invaginations

Gingival invaginations are a frequent finding during tooth extraction and following orthodontic space closure. Based on the interdental localization and sometimes pronounced depth, it has been suggested that a gingival invagination may impede oral hygiene. In Part I of this series, the time until active tooth movement and the localization of extraction were identified as potential risk factors for the development of gingival invagination. The aims of the present study were the analysis of the microbial spectrum of a gingival invagination in comparison with pool samples of the sulcus of Ramfjord teeth, on the one hand, and the importance of genetic variations of the pro-inflammatory mediator interleukin-1 (IL-1) and its receptor antagonist (IL-1-RN), on the other hand. In addition, a possible role of smoking as a risk factor was evaluated. A total of 30 patients with (n=16) and without (n=14) gingival invagination were examined for the presence of eleven periodontal pathogen bacterial species with a commercially available test (micro-IDent®Plus, Hain Lifescience, Nehren, Germany). The genetic evaluation was performed with the GenoType® IL-1 test (Hain Lifescience). The results of the microbiological analysis of gingival invaginations showed that the bacterial flora might differ or even be higher than the pool sample from sulcus regions. The genetic evaluation demonstrated that in the group without gingival invagination only 14% showed an IL-1 polymorphism, whereas this value was twice as high (35%) in the group with gingival invagination. In addition, a combination of both polymorphisms IL-1 and IL-1-RN was only found in patients with gingival invagination (25%). Interestingly, smoking patients showed a significant increase of the severity of the gingival invagination. This retrospective study demonstrated that gingival invagination might be accompanied with an altered microbiological bacterial spectrum and a genetic IL-1 polymorphism. In addition, smoking was identified as another potential risk factor for the severity of gingival invaginations.

Treponema denticola chymotrypsin-like proteinase (CTLP) integrates spirochaetes within oral microbial communities

Treponema denticola is found ubiquitously in the human oral cavity and is mainly associated with bacterial communities implicated in the establishment and development of periodontal disease. The ability to become integrated within biofilm communities is crucial to the growth and survival of oral bacteria, and involves inter-bacterial coaggregation, metabolic cooperation, and synergy against host defences. In this article we show that the chymotrypsin-like proteinase (CTLP), found within a high-molecular-mass complex on the cell surface, mediates adherence of T. denticola to other potential periodontal pathogens, Porphyromonas gingivalis, Fusobacterium nucleatum, Prevotella intermedia and Parvimonas micra. Proteolytic activity per se did not appear to be required for the interactions, and expression of the major outer-sheath protein (Msp) was not necessary, except for binding Parv. micra. Biofilms of densely packed cells and matrix, up to 40 µm in depth, were formed between T. denticola and P. gingivalis on salivary pellicle, with T. denticola cells enriched in the upper layers. Expression of CTLP, but not Msp, was critical for dual-species biofilm formation with P. gingivalis. T. denticola did not form dual-species biofilms with any of the other three periodontal bacterial species under various conditions. Synergy between T. denticola and P. gingivalis was also shown by increased inhibition of blood clotting, which was CTLP-dependent. The results demonstrate the critical role of CTLP in interactions of T. denticola with other oral micro-organisms, leading to synergy in microbial community development and host tissue pathogenesis.

Association between periodontal pathogens and risk of nonfatal myocardial infarction

The direct effect of periodontal pathogens on atherosclerotic plaque development has been suggested as a potential mechanism for the observed association between periodontal disease and coronary heart disease, but few studies have tested this theory. (i) To assess the association of periodontal pathogens in periodontal pockets with the risk of myocardial infarction (MI) and (ii) to assess whether an increase in the number of periodontal bacterial species increases the risk of MI. A total of 313 cases and 747 controls, consisting of Caucasian men and women from Western New York, aged 35 to 69 years, were recruited for this study. The presence of microorganisms was assessed by indirect immunofluorescence microscopy, using species-specific polyclonal and monoclonal serodiagnostic reagents. The presence of six periodontal pathogens, Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Prevotella intermedia (Pi), Campylobacter recta (Cr), Fusobacterium nucleatum (Fn), and Eubacterium saburreum (Es), and their co-occurrence (0-6) was compared with the odds of having myocardial infarction. Univariate analyses revealed a higher percentage of the presence of each bacterium in cases compared to controls. In multivariate analyses, only Tf and Pi were statistically associated with an increase in the odds of having MI [Odds ratio OR=1.62; 95% CI (1.18-2.22); and 1.40; 95% (1.02-1.92), respectively] after adjusting for age, gender, education, cholesterol, high blood pressure, diabetes, and total pack-years of cigarette smoking. An increase in the number of different periodontal bacteria in pockets was also found to increase the odds of MI [adjusted OR=1.14; 95% CI (1.03-1.26)]. Participants who had three species or more of periodontal pathogens had about 2-fold increase in odds of having nonfatal MI than those who did not have any type of bacterial species [OR=2.01 (1.31-3.08)]. The presence of periodontal pathogens, specifically Tf or Pi, and an increase in total burden of periodontal pathogenic species were both associated with increased odds of having MI. However, further studies are needed to better assess any causal relationship, as well as the biological mechanisms underlying this association.

Successful application of molecular biological technique for evaluation of changes in periodontopathic bacteria in Japanese children with developmental disabilities

Developments in molecular biological techniques enables rapid and easy identification of periodontopathic bacterial species in clinical specimens. However, there are few reports regarding their application for community dentistry. The aim of this study was to show successful application of a molecular biological technique for evaluation of changes in periodontal bacterial species in children at daycare centers. We studied 187 children who received oral examinations in 2009 and 186 who received examinations in 2010, among whom 102 were examined in both years. Clinical parameters regarding periodontal conditions were evaluated and the distribution of 10 periodontopathic species in dental plaque specimens were determined by polymerase chain reaction. Periodontal pocket depth values in the 2010 group were significantly smaller than those in 2009. When the subjects were divided into those with (positive group) and without (negative group) Porphyromonas gingivalis , Treponema denticola , Tannerella forsythia , or Campylobacter rectus in 2009, the positive group had significantly smaller periodontal pocket values than the negative group. In addition, the rate of subjects with P. gingivalis , T. denticola , T. forsythia , or C. rectus in the positive group in 2010 was significantly reduced. Our findings demonstrate that molecular biological methods provide more information as compared to a standard clinical examination when evaluating changes of periodontal conditions in the field of community dentistry.

Microbial profile of ligature-induced periodontitis in rats

Objective The aim of this study was to evaluate the composition of the biofilm accumulated around ligatures in rats by checkerboard DNA–DNA hybridization using probes made from human oral bacterial species. Methods 12 Wistar rats were selected for this study. One of the mandibular first molars of each animal received a ligature, while the contralateral tooth was left unligated to be used as a control. Forty-two days later, the ligatures and one sample of biofilm from each unligated teeth were analyzed by checkerboard DNA–DNA hybridization for 40 human periodontal species. The area of bone loss in the furcation area was determined histometrically. Results The unligated teeth did not present any of the bacterial species tested. Twenty five species were detected in the ligatures. Streptococcus- and Actinomyces-like species were found in high mean counts, followed by Fusobacterium-, Prevotella nigrescens- and Parvimonas micra-like species and Porphyromonas gingivalis- and Aggregatibacter actinomycetemcomitans-like species. Greater bone loss was observed in the furcation area of the ligated than of the unligated group ( p < 0.0001). Conclusion At 42 days, the ligature biofilm in rats presents various bacterial species that hybridize to probes of periodontal bacterial species commonly observed in human.

Bacterial profiles of oral streptococcal and periodontal bacterial species in saliva specimens from Japanese subjects

Objective Recent developments in molecular biological techniques have increased understanding of the distribution of oral bacterial species in clinical specimens, though few investigations have been conducted to simultaneously detect oral streptococcal and periodontal species in the same specimens. The purpose of the present study was to investigate the distribution and correlation of 6 oral streptococcal and 6 periodontal species in saliva specimens taken from children and their mothers. Design Seventy-four pairs of children and their mothers were approved to participate in this study. Saliva specimens were collected and bacterial DNA extracted, which was subjected to PCR analyses using species-specific sets of primers. The combinations of species able to be detected simultaneously were determined by statistical analyses. Results Streptococcus sobrinus and Porphyromonas gingivalis were detected more often in the mothers than the children. Streptococcus mutans, Streptococcus sanguinis, and Streptococcus oralis were detected simultaneously in a significant number of specimens, while the presence of Campylobacter rectus was correlated with the presence of at least one of the red complex species ( P. gingivalis, Treponema denticola and Tannerella forsythensis). On the other hand, no correlation was shown between the rates of detection of oral streptococcal and periodontal species. Conclusions Our results indicate that among streptococcal and periodontal species, several are able to coexist in saliva, while the presence of both does not have an influence on each other.

Distribution of 10 periodontal bacterial species in children and adolescents over a 7‐year period

There is scant information available regarding the distribution of periodontal bacterial species in children and adolescents over an extended period. The purpose of this study was to compare bacterial profiles in the same individuals over a period of 7 years. Twenty-six children and adolescents from whom dental plaque and saliva specimens were obtained during both the first (1999-2000) and second (2006-2007) periods, were analyzed. Bacterial DNA was extracted from each specimen and the presence of 10 periodontal bacterial species was determined using a PCR method, with a focus on the red complex species of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Subjects with red complex species in saliva specimens obtained during the second collection possessed a significantly higher number of total bacterial species than those without. The detection rate of the red complex species in the second collection period samples was significantly greater in subjects who had two or more species detected in samples taken during the first collection compared with the other subjects. Subjects possessing red complex species may be at possible risk for infection with a high number of periodontal bacterial species during adolescent and younger adult years.

Relationship of Porphyromonas gingivalis with glycemic level in patients with type 2 diabetes following periodontal treatment

The aim of this study was to assess the relationship between serum glycemic levels and subgingival microbial profile alteration following periodontal treatment in patients with type 2 diabetes mellitus. We studied 30 periodontitis patients with type 2 diabetes mellitus who received full-mouth subgingival debridement by analyzing their subgingival microbial profiles using a polymerase chain reaction method at baseline and various time-points for 12 months following treatment. Concurrently, probing pocket depth, bleeding on probing, and metabolic parameters, including glycated hemoglobin A1c (HbA1c), blood sugar level, C-reactive proteins, total cholesterol, triglyceride, and high-density and low-density lipoprotein cholesterol, were recorded. Periodontal conditions were significantly improved after treatment, and the occurrence rates of periodontal bacterial species, including Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, and Prevotella intermedia, were also reduced. Interestingly, P. gingivalis was detected more frequently in subjects with increased HbA1c values after periodontal treatment than in those patients with decreased HbA1c values. Furthermore, P. gingivalis with type II fimbriae was detected only in HbA1c-increased subjects, while improvements in HbA1c values were observed only in subjects without type II clones. These results suggest that glycemic level in diabetes is affected by the persistence of P. gingivalis, especially clones with type II fimbriae, in periodontal pockets.