Differences in immune response to Porphyromonas gingivalis

Revisiting Socransky's Complexes: A Review Suggesting Updated New Bacterial Clusters (GF-MoR Complexes) for Periodontal and Peri-Implant Diseases and Conditions

This review aimed to identify newly discovered bacteria from individuals with periodontal/peri-implant diseases and organize them into new clusters (GF-MoR complexes) to update Socransky's complexes (1998). For methodological development, the PCC (Population, Concept, Context) strategy was used for the focus question construction: "In patients with periodontal and/or peri-implant disease, what bacteria (microorganisms) were detected through laboratory assays?" The search strategy was applied to PubMed/MEDLINE, PubMed Central, and Embase. The search key terms, combined with Boolean markers, were (1) bacteria, (2) microbiome, (3) microorganisms, (4) biofilm, (5) niche, (6) native bacteria, (7) gingivitis), (8) periodontitis, (9) peri-implant mucositis, and (10) peri-implantitis. The search was restricted to the period 1998-2024 and the English language. The bacteria groups in the oral cavity obtained/found were retrieved and included in the GF-MoR complexes, which were based on the disease/condition, presenting six groups: (1) health, (2) gingivitis, (3) peri-implant mucositis, (4) periodontitis, (5) peri-implantitis, and (6) necrotizing and molar-incisor (M-O) pattern periodontitis. The percentual found per group refers to the number of times a specific bacterium was found to be associated with a particular disease. A total of 381 articles were found: 162 articles were eligible for full-text reading (k = 0.92). Of these articles, nine were excluded with justification, and 153 were included in this review (k = 0.98). Most of the studies reported results for the health condition, periodontitis, and peri-implantitis (3 out of 6 GF-MoR clusters), limiting the number of bacteria found in the other groups. Therefore, it became essential to understand that bacterial colonization is a dynamic process, and the bacteria present in one group could also be present in others, such as those observed with the bacteria found in all groups (Porphyromonas gingivalis, Tannarela forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans) (GF-MoR's red triangle). The second most observed bacteria were grouped in GF-MoR's blue triangle: Porphyromonas spp., Prevotela spp., and Treponema spp., which were present in five of the six groups. The third most detected bacteria were clustered in the grey polygon (GF-MoR's grey polygon): Fusobacterium nucleatum, Prevotella intermedia, Campylobacter rectus, and Eikenella corrodens. These three geometric shapes had the most relevant bacteria to periodontal and peri-implant diseases. Specifically, per group, GF-MoR's health group had 58 species; GF-MoR's gingivitis group presented 16 bacteria; GF-MoR's peri-implant mucositis included 17 bacteria; GF-MoR's periodontitis group had 101 different bacteria; GF-MoR's peri-implantitis presented 61 bacteria; and the last group was a combination of necrotizing diseases and molar-incisor (M-I) pattern periodontitis, with seven bacteria. After observing the top seven bacteria of all groups, all of them were found to be gram-negative. Groups 4 and 5 (periodontitis and peri-implantitis) presented the same top seven bacteria. For the first time in the literature, GF-MoR's complexes were presented, gathering bacteria data according to the condition found and including more bacteria than in Socransky's complexes. Based on this understanding, this study could drive future research into treatment options for periodontal and peri-implant diseases, guiding future studies and collaborations to prevent and worsen systemic conditions. Moreover, it permits the debate about the evolution of bacterial clusters.

Tobacco-enhanced biofilm formation by Porphyromonas gingivalis and other oral microbes

Microbial biofilms promote pathogenesis by disguising antigens, facilitating immune evasion, providing protection against antibiotics and other antimicrobials and, generally, fostering survival and persistence. Environmental fluxes are known to influence biofilm formation and composition, with recent data suggesting that tobacco and tobacco-derived stimuli are particularly important mediators of biofilm initiation and development in vitro and determinants of polymicrobial communities in vivo. The evidence for tobacco-augmented biofilm formation by oral bacteria, tobacco-induced oral dysbiosis, tobacco-resistance strategies, and bacterial physiology is summarized herein. A general overview is provided alongside specific insights gained through studies of the model and archetypal, anaerobic, Gram-negative oral pathobiont, Porphyromonas gingivalis.

Variations in IgG antibody subclass responses to oral bacteria: Effects of periodontal disease and modifying factors

BACKGROUND AND OBJECTIVE

Local and systemic IgG antibodies or oral bacteria have been described with periodontitis. We extended these observations by assessing the impact of a range of intrinsic factors on serum IgG subclass antibodies to both commensal and pathogenic oral bacteria that would contribute to variations in immune protection or disease susceptibility in periodontitis have not been described.

METHODS

Subjects (n = 278) were classified as healthy, gingivitis, or periodontitis and categorized as mild, moderate, and severe periodontitis. Demographic stratification included sex, age, race/ethnicity, smoking, and obesity. Whole formalin-fixed bacteria were used as antigens to detect serum immunoglobulin (Ig)G subclass antibody levels using an ELISA.

RESULTS

The greatest differences in variations in IgG subclasses occurred in periodontitis versus health or gingivitis to bacteria considered oral pathogens (eg, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola) with IgG1, IgG2, and IgG4 increased by three- to sevenfold with Pg. Differences in subclass levels and distribution were also observed related to disease severity, particularly related to individual subclass responses to Pg. Examination of the overall population showed that females had elevated antibody, reflected by elevated IgG2 amounts/proportions. The older group of subjects demonstrated elevated antibody to multiple oral bacteria, lacking any particular subclass pattern. IgG2 antibody to Aa and Pg was increased in smokers. Multiple IgG subclass antibody levels to oral pathogens were significantly decreased in the obese subset within this population.

CONCLUSION

This investigation identified patterns of IgG subclass antibody responses to oral bacteria and demonstrated substantial effects of disease impacting the level and subclass distribution of antibody to an array of oral bacteria. Altered subclass antibody profiles most often in IgG2 levels and for antibody to P. gingivalis were found related to sex, age, disease severity, race/ethnicity, smoking, and obesity to both pathogens and commensal bacteria.

The Impact of Smoking on Subgingival Microflora: From Periodontal Health to Disease

Periodontal disease is one of the most common diseases of the oral cavity affecting up to 90% of the worldwide population. Smoking has been identified as a major risk factor in the development and progression of periodontal disease. It is essential to assess the influence of smoking on subgingival microflora that is the principal etiological factor of the disease to clarify the contribution of smoking to periodontal disease. Therefore, this article reviews the current research findings regarding the impact of smoking on subgingival microflora and discusses several potential mechanisms. Cultivation-based and targeted molecular approaches yield controversial results in determining the presence or absence of smoking-induced differences in the prevalence or levels of certain periodontal pathogens, such as the “red complex.” However, substantial changes in the subgingival microflora of smokers, regardless of their periodontal condition (clinical health, gingivitis, or periodontitis), have been demonstrated in recent microbiome studies. Available literature suggests that smoking facilitates early acquisition and colonization of periodontal pathogens, resulting in an “at-risk-for-harm” subgingival microbial community in the healthy periodontium. In periodontal diseases, the subgingival microflora in smokers is characterized by a pathogen-enriched community with lower resilience compared to that in non-smokers, which increases the difficulty of treatment. Biological changes in key pathogens, such as Porphyromonas gingivalis, together with the ineffective host immune response for clearance, might contribute to alterations in the subgingival microflora in smokers. Nonetheless, further studies are necessary to provide solid evidence for the underlying mechanisms.

The anti-nociceptive effects of Porphyromonas gingivalis lipopolysaccharide

OBJECTIVE

The objective of this study was to assess the effect of Porphyromonas gingivalis lipopolysaccharide (PG LPS) on acute pain-related behaviour induced in rats and to measure its impact on the levels of pro-inflammatory cytokines (IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines.

DESIGN

The Brennan model was used to induce acute pain like signs in rats' hind paw. Twenty-four hours following the surgery the rats were divided into 5 groups and the affected paws were injected with 0.2 m l of one of three commercialized forms PG LPS doses (high - 1 mg/ml, medium - 0.6 mg/m l and low - 0.2 mg/m l), diclofenac sodium (1 mg/kg) or saline. Tactile allodynia, mechanical hyperalgesia, body temperature and paw swelling were assessed at baseline, 24 h postoperatively and 2 h after the paw injection. The affected and contra-lateral paw tissue was assessed for the mentioned above cytokines levels employing enzyme-linked immunosorbent assay.

RESULTS

This study may suggest that PG LPS can reduce pain like behaviour via increased levels of anti-inflammatory cytokine IL-10 (5900 ± 748, p < 0.05). The high PG LPS dose and diclofenac reduced the tactile allodynia and mechanical hyperalgesia significantly (42.2 ± 4 and1.6 ± 0.3, p < 0.05). PG LPS high dose increase IL-10 levels while diclofenac reduces IL-1β levels significantly (5900 ± 748 and 1760 ± 271.2). The LPS administration had no effect on paw swelling and did not increase rat's body temperature.

CONCLUSION

The results demonstrated that PG LPS local application could possess anti- nociceptive properties, which at least in part is mediated by an increase in IL-10 levels.

Smoking and periodontal microorganisms

Resolution of dysbiosis following treatment for periodontal disease and tobacco dependence has been reported in longitudinal intervention studies. In the present report, we evaluated the biological findings regarding the effect of smoking on the periodontal microbiome. A standardized electronic search was conducted using MEDLINE; overall, 1099 papers were extracted. Studies that addressed the relationship between tobacco and periodontal pathogens were included. Finally, 42 papers were deemed appropriate for the present review. Functional changes in periodontal pathogens exposed to nicotine and cigarette smoke extract support the clinical findings regarding dysbiosis of the subgingival microbiome. Dysbiosis of the periodontal microbiome was presented in smokers regardless of their periodontal condition (healthy, gingivitis, or periodontitis) and remained significant only in smokers even after the resolution of experimentally-induced gingivitis and following reduction of clinical signs of periodontitis with non-surgical periodontal treatment and over 3 months post-therapy. Based on these findings, smoking cessation in periodontitis patients is beneficial for promoting a health-compatible subgingival microbial community. To maximize the benefits of these interventions in dental settings, further studies on periodontal microbiome are needed to elucidate the impact of tobacco intervention on preventing recurrence of periodontal destruction in the susceptible subjects.

Tobacco-induced suppression of the vascular response to dental plaque

Cigarette smoking presents oral health professionals with a clinical and research conundrum: reduced periodontal vascular responsiveness to the oral biofilm accompanied by increased susceptibility to destructive periodontal diseases. This presents a significant problem, hampering diagnosis and complicating treatment planning. The aim of this review is to summarize contemporary hypotheses that help to explain mechanistically the phenomenon of a suppressed bleeding response to dysbiotic plaque in the periodontia of smokers. The influence of smoke exposure on angiogenesis, innate cell function, the production of inflammatory mediators including cytokines and proteases, tobacco-bacteria interactions, and potential genetic predisposition are discussed.