Designing Novel Multi-Epitope Vaccine Construct against Prevotella intermedia-Interpain A: An Immunoinformatics Approach

Background and Objectives: Periodontitis is a chronic multifactorial inflammatory infectious disease marked by continuous degradation of teeth and surrounding parts. One of the most important periodontal pathogens is P. intermedia, and with its interpain A proteinase, it leads to an increase in lethal infection. Materials and Methods: The current study was designed to create a multi-epitope vaccine using an immunoinformatics method that targets the interpain A of P. intermedia. For the development of vaccines, P. intermedia peptides InpA were found appropriate. To create a multi-epitope vaccination design, interpain A, B, and T-cell epitopes were found and assessed depending on the essential variables. The vaccine construct was evaluated based on its stability, antigenicity, and allergenicity. Results: The vaccine construct reached a more significant population and was able to bind to both the binding epitopes of major histocompatibility complex (MHC)-I and MHC-II. Through the C3 receptor complex route, P. intermedia InpA promotes an immunological subunit. Utilizing InpA-C3 and vaccination epitopes as the receptor and ligand, the molecular docking and dynamics were performed using the ClusPro 2.0 server. Conclusion: The developed vaccine had shown good antigenicity, solubility, and stability. Molecular docking indicated the vaccine's 3D structure interacts strongly with the complement C3. The current study describes the design for vaccine, and steady interaction with the C3 immunological receptor to induce a good memory and an adaptive immune response against Interpain A of P. intermedia.

Express Diagnostics of Proteolytic Activity of Periodontopathogens-Methodological Approach

The species spectrum of the oral microbiome is considered to be the key factor in the development and progression of periodontal inflammatory disorders. The “red complex” including Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola has the highest pathogenic potential. These bacteria have several biochemical mechanisms that allow them to colonize and destroy periodontal tissues. Proteolytic enzymes play a crucial role in this process. Early diagnosis of pathological conditions induced by microbial contamination allows for the timely treatment of periodontitis. Otherwise, the development of the disease may lead to tooth loss. A total of 48 patients aged 18 to 65 years old who required professional oral hygiene were recruited for this clinical study. Microbial content analysis of dental plaque from the interdental space and the back of the tongue was performed using real-time PCR. To determine the proteolytic activity of oral bacteria, the new express diagnostic method was applied (diagnostic sensitivity, 0.875; specificity, 0.928). The results demonstrate a strong and significant correlation between the new method and the PCR analysis (r = 0.785, p < 0.001). These results show that the new express method can be valuable as an early diagnostic method for periodontal inflammatory disorders caused by the “red complex” bacteria.

The Ability of a Novel Trypsin-like Peptidase Activity Assay Kit to Detect Red-Complex Species

The trypsin-like peptidase activity assay kit measures the trypsin-like protease produced by three red-complex species, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, causing periodontitis, and detects the presence of these bacteria in samples. The purpose of this study was to investigate the relationship between the detection of TLPs by a novel TLP-AA, ADCHECK and the detection of red-complex pathogens by real-time PCR using tongue swabs from patients with periodontitis. The detection limit of trypsin-like protease activity by ADCHECK was validated using the culture supernatants of two different Porphyromonas gingivalis bacterial strains. Real-time PCR was performed to determine the number of red-complex species in the tongue coatings of patients with periodontal disease. Trypsin-like protease activity in tongue-swab samples was scored using ADCHECK. ADCHECK successfully detected trypsin-like protease activity in 103 Porphyromonas gingivalis bacterial strains. The specificity, positive predictive value, negative predictive value, and accuracy of ADCHECK for the presence of red-complex pathogens determined by real-time PCR were 90%, 97%, 98%, and 92%, respectively. ADCHECK is an effective tool for the detection of red-complex pathogens.

Bacteria and oral cavity: a new story to tell

Periodontal diseases include a mild and reversible form named gingivitis (GI), and periodontitis (PD) that is the main cause of tooth loss in adults. GI, that affects gums and coronal junctional epithelium, as well as periodontitis, that is characterized by loss of connective tissue attachment, are caused by a persistent inflammatory response promoted by alteration of periodontal biofilm. The aim of the study was to test whether the prevalence of each species was associated with a particular clinical condition. Periodontal evaluation of 756 unrelated patients was performed by the Periodontal Screening and Recording (PSR) system. Subgingival samples were obtained from the site with the worst PSR score. A selection of eleven bacterial species was evaluated by quantitative real time PCR. Quantitative and qualitative analyses help to better understand the microbial changes associated with different stages of periodontal disease.

Paleogenomic insights into the red complex bacteria Tannerella forsythia in Pre-Hispanic and Colonial individuals from Mexico

The 'red complex' is an aggregate of three oral bacteria (Tannerella forsythia, Porphyromonas gingivalis and Treponema denticola) responsible for severe clinical manifestation of periodontal disease. Here, we report the first direct evidence of ancient T.forsythia DNA in dentin and dental calculus samples from archaeological skeletal remains that span from the Pre-Hispanic to the Colonial period in Mexico. We recovered twelve partial ancient T. forsythia genomes and observed a distinct phylogenetic placement of samples, suggesting that the strains present in Pre-Hispanic individuals likely arrived with the first human migrations to the Americas and that new strains were introduced with the arrival of European and African populations in the sixteenth century. We also identified instances of the differential presence of genes between periods in the T. forsythia ancient genomes, with certain genes present in Pre-Hispanic individuals and absent in Colonial individuals, and vice versa. This study highlights the potential for studying ancient T. forsythia genomes to unveil past social interactions through analysis of disease transmission. Our results illustrate the long-standing relationship between this oral pathogen and its human host, while also unveiling key evidence to understand its evolutionary history in Pre-Hispanic and Colonial Mexico. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

Association of specific microorganisms with endodontic signs and symptoms. A comparative study

Aim

The study aimed to evaluate the association of root canal microorganisms red complex and E. facealis with endodontic clinical signs and symptoms using polymerase chain reaction.

Materials and Methods

Bacterial samples were obtained using sterile paper points from the teeth of 100 subjects divided into two groups; Group I: 50 individuals with primary tooth infections and Group II: 50 individuals with failed endodontic treatment having the secondary infection. DNA extracted from samples was analyzed for endodontic pathogens by using species-specific primers.

Results

The pain was noticed in 66%, (33 of 50 subjects) in primary infection and 60% (30 of 50) in a secondary infection. A statistically significant association between pain and E. faecalis bacteria observed both in primary infection and secondary infection (P < 0.05). Tenderness on percussion was associated with 40% cases in Group I and 70% cases in Group II. The red complex accounted for 94% of cases associated with tenderness on percussion in primary infection while 86% of cases associated with secondary infection with a statistically significant association (P < 0.05).

Conclusion

Prevalence of red complex bacteria and E. faecalis suggested the association of studied bacteria with symptomatic infected pulp and periradicular diseases.

Detection of Red complex bacteria, P. gingivalis, T. denticola and T. forsythia in infected root canals and their association with clinical signs and symptoms

Aim:

This study aimed to investigate the association between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia employing polymerase chain reaction (PCR).

Materials and Methods:

Microbial samples were obtained from 60 cases with necrotic pulp with primary teeth infections. DNA extracted from samples were analyzed for endodontic pathogens by using species-specific primers.

Results:

P. gingivalis/T. denticola were detected in 15 symptomatic teeth associated with periapical lesions. T. forsythia/T. denticola were found in 16 symptomatic teeth associated with pain and swelling. P. gingivalis was detected in 9 teeth which were associated with pain, 2 with tenderness on percussion, and 15 with periapical lesions. Statistically significant associations were found between T. forsythia as well as T. denticola in relation to clinical findings of pain and swelling. (P < 0.05). Red complex bacteria showed no statistical significant association with the presence of signs and symptoms.

Conclusion:

Prevalence of P. gingivalis, T. denticola, and T. forsythia suggested association of these bacteria with symptomatic infected pulp and periradicular diseases.

The use of a new chemical device based on silver and cationic surfactants as a new approach for daily oral hygiene: A preliminary study on a group of periodontal patients

The aim of this study was to evaluate the abatement power of oral microbial loading of a new gel formulation based on the complex silver-2-mercaptobenzoate, chlorhexidine digluconate and didecyldimethylammonium chloride (named ADC) through polymerase chain reaction (PCR). The study sample consists of a group of 20 patients with chronic periodontal disease. Patients were over 25 years of age and did not undergo surgical or non-surgical periodontal treatment in the previous 6 months. The study sample was allotted into two groups of 10 patients each, homogeneous by age and sex. The test group received a bottle containing ADC gel, while the control group received an identical one containing placebo, similar to ADC in consistence, colour, taste and odour. Sub-gingival samples of four sites, one in each quadrant, of greatest probing depth in each patient were used. Microbiological analyses were performed at baseline and at day 15. Paired t test was performed to detect statistical significant reduction in total bacterial loading and oral pathogens in the study groups. The analysis showed a statistically significant reduction in the total bacterial loading evaluated pre- and post-treatment (P = 0.029) in the study groups. In the control group, the decrease in total bacterial loading was not significant (P = 0.279). Clinically, ADC gel does not have any side effects and discomfort such as pain, burning, tingling sensation or numbness and produces no adverse reactions in time. Our study aimed to evaluate the efficacy of a new chemical formulation with antibacterial properties to use for daily oral hygiene with a preliminary study. Our results showed a statistically significant reduction in total bacterial loading after treatment, but the limitations of our study do not allow us to demonstrate the clinical efficacy of the ADC gel.

Red complex: Polymicrobial conglomerate in oral flora: A review

Oral diseases are the complex host responses composed of a broad array of inflammatory cells, and cytokines, chemokines, and mediators derived from the cells resident in the gingival tissues, as well as from the emigrating inflammatory cells. A chronic polymicrobial challenge to the local host tissues triggers this response, which under certain circumstances, and in a subset of the population, leads to the progressing soft and hard tissue destruction that characterizes periodontitis. The red complex has been proposed as a pathogenic consortium, consisting of P. gingivalis, T. denticola, and T. forsythia. This review has attempted to examine the virulence potential and determinants of these commensal opportunists.

A hydrosilver gel for plaque control in adults affected by chronic periodontitis: Effects on the 'red complex' bacterial load. A prospective longitudinal pilot study using polymerase chain reaction analysis

In subjects affected by chronic periodontitis, the chemical control of plaque is a strategy aiming primarily at controlling infection and bacterial loading. The aim is to evaluate the bacterial loading of the so-called 'red complex' associated with a short-term use of a hydrosilver gel (HSG) by using an in vivo model in adult subjects affected by chronic periodontitis. This prospective short-term clinical trial involved 10 adult volunteers using a 15-day in vivo model. After receiving professional prophylaxis at baseline (t0), each volunteer performed daily applications of HSG at home. After 15 days (t1) from the first application, subgingival plaque samples were collected, and the bacterial loading of species belonging to the red complex was evaluated using polymerase chain reaction (PCR) analyses. The bacterial loading of the red complex showed no statistically significant difference between t0 and t1, although it tended to decrease. HSG can be used at home as an adjunct to domestic oral care because it seems a promising tool, but further studies are needed to involve a larger sample and a longer follow-up.

Red complex periodontal pathogens are risk factors for liver cirrhosis

Periodontal disease has been associated with liver disease; however, the identities of the periodontal disease-causing bacteria in patients with viral liver disease remain unknown. The aim of the present study was to determine the counts of the 3 periodontal pathogens that form the red complex in chronic periodontitis (Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola) and 3 other bacteria (Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Fusobacterium necrophorum) in patients with liver disease. A total of 47 patients with liver disease were divided into two groups based on the counts of the red complex bacteria: group A (high counts of red complex bacteria) and group B (low counts of red complex bacteria). The counts of the 6 types of bacteria in saliva and the prevalence of P. gingivalis-specific fimA genotype were determined. In addition, salivary occult blood tests and serological assays were performed. Univariate and multivariate logistic regression analyses were used to analyze the risk factors between the two groups of patients. Hepatitis C virus-related liver disease was the most frequent (41/47; 87.2%) occurrence followed by liver cirrhosis (LC; 12/47; 25.5%) and oral lichen planus (32/47; 68.1%). The significant risk factors between the two groups were LC, albumin (Alb) level, ratios of each bacteria and prevalence of the fimA II genotype. The 3 factors identified in the multivariate analysis to be associated with the red complex bacteria count were low Alb level (<3.7 g/dl), LC and fimA II genotype, with adjusted odds ratios of 6.93, 4.72 and 4.08, respectively (P<0.05). These data indicated that patients with LC were at increased risk of presenting with the red complex bacteria leading to periodontal disease progression. Therefore, these patients may need to take additional care of their oral health compared with patients without LC, which may prove beneficial for the maintenance of their general health.

[Clinical and microbiologic follow-up evaluations after non-surgical periodontal treatment with Nd: YAG laser and scaling and root planning]

OBJECTIVE

Our research aimed to detect the efficacy of non-surgical periodontal treatment with Nd: YAG laser and scaling and root planning (SRP) for chronic periodontitis.

METHODS

We recruited chronic periodontitis patients who have more than four teeth with clinical pocket depth of 4-8 mm. These teeth were distributed in four different zones within the oral cavity. Moreover, the teeth were single root teeth and not adjacent to each other. The subordinated teeth were randomized into four groups, as follows: no treatment (C group), simple SRP (SRP group), Nd: YAG laser after SRP treatment (SRP+L group), and SRP after Nd: YAG laser treatment (L+SRP group). The four experimental observation points were as follows: before treatment (baseline) and 1 week, 1 month, and 3 months after treatment. We measured clinical indicators and collected subgingival deposits in the four time points to analyze changes of red complex in periodontitis.

RESULTS

The clinical indicators were better in all treatment groups than in the control group. Comparison among treatment groups indicated that the value of bleeding on probing, periodontal probing depth, and clinical attachment loss showed no difference. However, the value of plaque index in SRP+L and L+SRP presented a significant reduction at 3 months after treatment. The percentages of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola in all treatment groups decreased after clinical treatment, and differences were observed among the treatment groups at different time points.

CONCLUSIONS

Non-surgical periodontal treatment with SRP and Nd: YAG laser is not more effective than SRP monotherapy. The sequence of laser treatment and SRP has no significant effect on the treatment. However, SRP with Nd: YAG laser was beneficial for plaque control. Non-surgical periodontal treatment with Nd: YAG laser may be used as an alternative to reduce and control the proliferation of microorganisms in persistent periodontitis, but it still needs further verification.

Silver-Based Chemical Device as an Adjunct of Domestic Oral Hygiene: A Study on Periodontal Patients

The use of chemical devices for periodontitis treatment has led to new strategies aiming primarily to control infections. Over the last few years, new chemical devices have been subjected to many scientific and medical studies. The purpose of the present study was to assess the effect of a new silver based chemical devices gel named "Hydrosilver Plus Gel", abbreviated here as Hydrosilver, on the pathogenic microorganisms, using Polymerase Chain Reaction (PCR) for microbiological analysis. Materials and methods: Ten patients with a diagnosis of chronic periodontitis in the age group >25 years were selected. None of these patients had received any surgical or non-surgical periodontal therapy, and demonstrated radiographic evidence of moderate bone loss. After scaling and root planning, patients received Hydrosilver to be used at home. Four non-adjacent sites in separate quadrants were selected in each patient for monitoring, based on criteria that the sites localise chronic periodontitis. Microbial analysis was analysed at baseline and at Day 15. SPSS program was used for statistical purposes and a paired samples correlation was performed at the end of the observation period. Results: Mean amounts of bacterial loading before and after Hydrosilver treatment reduced statistically significantly (p = 0.002). Conclusions: The present study demonstrated that Hydrosilver has a good impact on oral biofilm. Additional studies are needed to detect the efficacy of this chemical device.

Towards microbiome transplant as a therapy for periodontitis: an exploratory study of periodontitis microbial signature contrasted by oral health, caries and edentulism

BACKGROUND

Conventional periodontal therapy aims at controlling supra- and subgingival biofilms. Although periodontal therapy was shown to improve periodontal health, it does not completely arrest the disease. Almost all subjects compliant with periodontal maintenance continue to experience progressive clinical attachment loss and a fraction of them loses teeth. An oral microbial transplant may be a new alternative for treating periodontitis (inspired by fecal transplant). First, it must be established that microbiomes of oral health and periodontitis are distinct. In that case, the health-associated microbiome could be introduced into the oral cavity of periodontitis patients. This relates to the goals of our study: (i) to assess if microbial communities of the entire oral cavity of subjects with periodontitis were different from or oral health contrasted by microbiotas of caries and edentulism patients; (ii) to test in vitro if safe concentration of sodium hypochlorite could be used for initial eradication of the original oral microbiota followed by a safe neutralization of the hypochlorite prior transplantation.

METHODS

Sixteen systemically healthy white adults with clinical signs of one of the following oral conditions were enrolled: periodontitis, established caries, edentulism, and oral health. Oral biofilm samples were collected from sub- and supra-gingival sites, and oral mucosae. DNA was extracted and 16S rRNA genes were amplified. Amplicons from the same patient were pooled, sequenced and quantified. Volunteer's oral plaque was treated with saline, 16 mM NaOCl and NaOCl neutralized by ascorbate buffer followed by plating on blood agar.

RESULTS

Ordination plots of rRNA gene abundances revealed distinct groupings for the oral microbiomes of subjects with periodontitis, edentulism, or oral health. The oral microbiome in subjects with periodontitis showed the greatest diversity harboring 29 bacterial species at significantly higher abundance compared to subjects with the other assessed conditions. Healthy subjects had significantly higher abundance in 10 microbial species compared to the other conditions. NaOCl showed strong antimicrobial properties; nontoxic ascorbate was capable of neutralizing the hypochlorite.

CONCLUSIONS

Distinct oral microbial signatures were found in subjects with periodontitis, edentulism, or oral health. This finding opens up a potential for a new therapy, whereby a health-related entire oral microbial community would be transplanted to the diseased patient.

The detection of BANA micro-organisms in adult periodontitis before and after scaling and root planing by BANA-Enzymatic™ test kit: An in vivo study

Background:

Many paraclinical methods are available today for an accurate assessment of the periodontal status prior and during the periodontal treatment. The microbial-enzymatic N-benzoyl-DL-arginine-2-napthylamide (BANA) test is one of the modern alternatives to bacterial cultures. It detects the presence of three periodontal pathogens in the subgingival plaque (Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia).

Aims and Objective:

The aim and objective of this study was to detect the presence of BANA micro-organisms and also to determine the effect of scaling and root planning in adult periodontitis patients.

Materials and Methods:

A total number of 20 patients (80 sites) all having periodontitis were selected. Four test sites (permanent molar from each quadrant) were selected from each patient and assessed for plaque index, bleeding index and pocket depth before and after scaling and root planning. BANA test was used for the detection and prevalence of the “red complex” bacteria in plaque samples.

Results:

Showed that the BANA tests are statistically correlated with the severity of periodontal destruction. There was a significant correlation between the BANA test results and the quantity of bacterial plaque, the test being influenced by the composition of bacterial plaque.

Conclusion:

This study encourages the use of such chair-side tests for a proper diagnosis of periodontal disease and for a good evaluation of the treatment results.

The novel association between red complex of oral microbe and body mass index in healthy Japanese: a population based cross-sectional study

Microbiota has been thought to be one of important environmental factors for obesity or Type 2 diabetes mellitus. Among oral microbe, Porphyromonas gingivalis, Treponema denticola and Tannellera forsythia are known as risk factors, so called red complex, for periodontitis. Red complex could also be a risk factor for obesity. However, recent study indicated that obesity was not improved by periodontal therapy. Thus, we performed a cross sectional study to reveal the association of oral microbe with body mass index in a healthy population. Healthy individuals were randomly recruited. The infections of oral microbe were identified by Taqman polymerase chain reaction. The relationships between number of red complex and body mass index or waist circumference were analyzed. Two hundred and twenty-two apparently healthy Japanese were enrolled. BMI and waist circumference as well as age, periodontitis, number of brushing teeth were significantly associated with the number of red complex after adjusting covariance. The effect size of body mass index or waist circumference was 0.023 (p = 0.028) or 0.024 (p = 0.024), respectively. Body mass index and waist circumference were independently associated with the number of red complex among apparently healthy Japanese. The current observation implies the possibility that oral microbe was associated with obesity in healthy population.

Secretome of gingival epithelium in response to subgingival biofilms

Periodontitis is the chronic inflammatory destruction of periodontal tissues as a result of bacterial biofilm formation on the tooth surface. Proteins secreted by the gingival epithelium challenged by subgingival biofilms represent an important initial response for periodontal inflammation. The aim of this in vitro study was to characterize the whole secreted proteome of gingival epithelial tissue challenged by subgingival biofilms, and to evaluate the differential effects of the presence of the red-complex species in the biofilm. Multi-layered human gingival epithelial cultures were challenged with a 10-species in vitro biofilm model or its seven-species variant excluding the red complex. Liquid chromatography-tandem mass spectrometry for label-free quantitative proteomics was applied to identify and quantify the secreted epithelial proteins in the culture supernatant. A total of 192 proteins were identified and quantified. The biofilm challenge resulted in more secreted proteins being downregulated than upregulated. Even so, presence of the red complex in the biofilm was responsible for much of this downregulatory effect. Over 24 h, the upregulated biological processes were associated with inflammation and apoptosis, whereas the downregulated processes were associated with the disruption of epithelial tissue integrity and impairment of tissue turnover. Over 48 h, negative regulation of several metabolic processes and degradation of various molecular complexes was further intensified. Again, many of these biological regulations were attributed to the presence of the red complex. In conclusion, the present study provides the secreted proteome profile of gingival epithelial tissue to subgingival biofilms, and identifies a significant role for the red-complex species in the observed effects.

Investigate the correlation between clinical sign and symptoms and the presence of P. gingivalis, T. denticola, and T. forsythia individually or as a "Red complex" by a multiplex PCR method

AIM

The aim of this study was to investigate the correlation between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia or their association by Multiplex polymerase chain reaction assay.

MATERIALS AND METHODS

Microbial samples were taken from 30 cases with necrotic pulp tissues in primary infections. DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens by using species-specific primers.

RESULTS

P. gingivalis, T. denticola, T. forsythia, and Red Complex were present in 11, 17, 4, and 2 canals, respectively. Clinical and statistically significant relationships were found between T. forsythia and mobility and between T. denticola and swelling. (P < 0.05). Presence of other Red complex bacteria shows clinical association with presence of signs and symptoms but no statistically significant relationship.

CONCLUSION

The high prevalence of P. gingivalis, T. denticola, and T. forsythia in the examined samples suggests that these bacteria are related to the etiology of symptomatic periradicular diseases.

Quantitative analysis of classical and new putative periodontal pathogens in subgingival biofilm: a case-control study

BACKGROUND AND OBJECTIVES

A number of species/phylotypes have been newly implicated as putative periopathogens. The objective of this study was to explore associations among classical and new pathogens in subgingival biofilm and to assess their relative importance to chronic periodontitis.

MATERIAL AND METHODS

Pooled subgingival biofilm samples were obtained from 40 patients with chronic periodontitis and 40 healthy controls. Taqman q-PCR assays were used to determine the absolute and relative counts of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Parvimonas micra, Filifactor alocis, oral Synergistetes and oral TM7s. Microbial associations were assessed using cluster analysis. Different statistical models were used to explore associations between microbial parameters and periodontitis.

RESULTS

The median log and relative counts were lowest for TM7s (4.4 and 0.0016%, respectively) and highest for oral Synergistetes (7.2 and 1.4%, respectively). Oral Synergistetes clustered strongly with the red complex, particularly T. forsythia (100% rescaled similarity). All species/phylotypes except TM7s were significantly associated with periodontitis (Mann-Whitney test; p ≤ 0.005). However, P. gingivalis and F. alocis lost association after adjusting for confounders (ordinal regression). In receiving operator characteristic curve analysis, the log counts of oral Synergistetes were the best markers of periodontitis (82.5% sensitivity and specificity), followed by those of T. forsythia, P. micra and T. denticola. In prediction analysis, however, P. micra was the only microbial predictor of periodontal parameters.

CONCLUSIONS

Oral Synergistetes are presented here as new members of the red complex, with relative importance to periodontitis exceeding that of the classical members. P. micra is shown as an important periodontal pathogen warranting more attention.

Life in a Diverse Oral Community - Strategies for Oxidative Stress Survival

BACKGROUND

While the oral cavity harbors more than 680 bacterial species, the interaction and association of selected bacterial species play a role in periodontal diseases. Bacterial species including Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, a consortium previously designated as the "red complex" is now being expanded to include other new emerging pathogens that are significantly associated with periodontal disease.

HIGHLIGHT

In addition to novel mechanisms for oxidative resistance of individual species, community dynamics may lead to an overall strategy for survival in the inflammatory environment of the periodontal pocket. Complex systems controlled by response regulators protect against oxidative and nitrosative stress.

CONCLUSION

The combination of these multifaceted strategies would provide a comprehensive defense and support system against the repetitive host immune response to promote microbial persistence and disease.