Periodontitis is a polymicrobial infection of tooth-supporting tissues. This cross-sectional study aimed to examine the associations between five target species and severe periodontitis in a Thai population. Using the CDC/AAP case definition, individuals diagnosed with no/mild and severe periodontitis were included. Quantitative analyses of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), and Prevotella intermedia (Pi) in subgingival plaque were performed using real-time polymerase chain reaction. The association between target species and severe periodontitis was examined using logistic regression analysis. The study subjects comprised 479 individuals with no/mild periodontitis and 883 with severe periodontitis. Bacterial prevalence and quantity were higher in subjects with severe periodontitis than in those with no/mild disease. In the fully adjusted model, all species except Tf showed a dose-dependent relationship with periodontitis. The mere presence of Pg, even in low amount, was significantly associated with severe periodontitis, while the amount of Aa, Td, and Pi had to reach the critical thresholds to be significantly associated with disease. Compared to individuals with low levels of both Td and Pi, high colonization by either Td or Pi alone significantly increased the odds of having severe periodontitis by 2.5 (95%CI 1.7–3.5) folds. The odds ratio was further increased to 14.8 (95%CI 9.2–23.8) in individuals who were highly colonized by both species. Moreover, the presence of Pg and high colonization by Aa were independently associated with severe periodontitis with odds ratios of 5.6 (95%CI 3.4–9.1) and 2.2 (95%CI 1.5–3.3), respectively. Our findings suggest that the presence of Pg and high colonization by Aa, Td, and Pi play an important role in severe periodontitis in this study population. We also demonstrate for the first time that individuals co-infected with Td and Pi were more likely to have periodontitis than were those infected with a single pathogen.

Interleukin (IL)-17 is present in inflammatory periodontal lesions, thus suggesting a role in mediating inflammation. We tested the hypothesis that IL-17, especially when combined with interferon (IFN)-gamma, may modulate the responses of human gingival fibroblasts (HGFs). IL-17 induced IL-8 and minimal intercellular adhesion molecule (ICAM)-1 expression. It had no effect on expression of HLA-DR, CD40, or the immune-suppressive enzyme indoleamine 2,3-dioxygenase (IDO). The effects of IL-17 on HGFs were compared with those of IFN-gamma. Unlike IL-17, IFN-gamma augmented the expression of HLA-DR, ICAM-1, and IDO, but not IL-8. Thus, IL-17 and IFN-gamma induce different HGF responses when administered separately. Interestingly, when IL-17 and IFN-gamma were combined, marked enhancement of ICAM-1, IL-8, and IDO expression by HGFs was observed. These findings suggest that IL-17, especially when combined with IFN-gamma, could play an important role in immune modulation through stimulation of HGFs in periodontal disease.

Our findings suggest that recirculating and gingiva-resident memory T cells could represent an important part of the immune surveillance network in the connective tissue, maintaining periodontal homeostasis. Imbalance of subgingival bacterial communities could damage gingival barrier allowing bacterial antigens to get access to the deeper connective tissue where they activate memory T cells leading to deleterious inflammation; a hallmark of periodontitis.

Aim To prospectively evaluate the association between periodontitis and the incidence of cardiovascular diseases (CVDs) in Thai adults. Materials and methods Medical data from the questionnaires and physical examinations of 1850 participants aged 47‒73 years from EGAT study were gathered. Random half‐mouth periodontal examination of each participant was performed by calibrated periodontists, and periodontal status was defined. The incidence of new CVD events, including coronary heart disease (CHD) and stroke, was verified by cardiologists. The Cox proportional hazard regression model was used to estimate hazard ratios (HRs). Results The prevalence of no/mild, moderate and severe periodontitis in the study participants was 11.7%, 52.7% and 35.6%, respectively. During the 13‐year follow‐up, CVD events occurred in 110 (5.9%) participants, with 82 (4.4%) from CHD and 28 (1.5%) from stroke. After adjusting for cardiovascular risk factors, a significant association between severe periodontitis and the incidence of CHD was found compared with the no/mild periodontitis group with an HR of 4.53 (95% confidence intervals: 1.08‒19.02). However, no significant association was seen when considering total CVD events and stroke outcome. Conclusions This study demonstrates that severe periodontitis is associated with an increased incidence of CHD, independent of established cardiovascular risk factors.

In this study, we re-visited the issue of hyper-responsiveness of monocytes to bacterial lipopolysaccharide (LPS) in aggressive periodontitis patients. We used whole-blood cultures to compare monocyte activation by Porphyromonas gingivalis LPS between Thai subjects with generalized aggressive periodontitis and those without periodontitis. Upon stimulation with P. gingivalis LPS, expression of co-stimulatory molecules on monocytes and expression of CD69 on NK and gamma delta T-cells were analyzed by flow cytometry, and the production of interleukin-1 beta and prostaglandin E(2) was monitored by ELISA. LPS stimulation resulted in a dose-dependent up-regulation of CD40, CD80, and CD86 on monocytes, and up-regulation of CD69 on NK cells and gamma delta T-cells in both the periodontitis and non-periodontitis groups. The levels of activation markers and the mediator production after LPS stimulation were quite similar for both groups. In conclusion, we did not observe hyper-responsiveness of monocytes to P. gingivalis LPS challenge in Thai patients with aggressive periodontitis.

Focused Clinical Question How can a clinician simply and quickly perform a periodontal screening and make a proper periodontal diagnosis using the 2018 proposed new periodontal classification? Summary The 2018 periodontal classification has been released, however, it is challenging for clinicians especially for the dental students to apply the published information in practice. A diagnostic flowchart was created for three of the most common periodontal conditions: health, gingivitis, and periodontitis. Additionally, flowcharts were proposed for the diagnosis of periodontitis severity and risk of progression by staging and grading. Probing depth was the first clinical parameter to categorize the type of diseases. Subsequently, bleeding on probing, radiographic bone loss/clinical attachment loss, and history of periodontal treatment were further added for making a proper diagnosis. Three clinical cases were given to demonstrate the use of the simplified proposed flowcharts. Conclusions The proposed diagnostic flowcharts are the user‐friendly tool to assist clinicians to perform an initial screening and diagnosis based on the 2018 newly proposed periodontal disease classification.

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