Humoral immune responses in gingival crevice fluid: local and systemic implications

The Concentration of Pro- and Antiangiogenic Factors in Saliva and Gingival Crevicular Fluid Compared to Plasma in Patients with Peripheral Artery Disease and Type 2 Diabetes

Several studies have investigated various biomarkers in relation to peripheral artery disease (PAD) for disease stratification and early-onset detection. In PAD, angiogenesis is required for tissue restoration and tissue perfusion. Considering changes in angiogenesis in patients with PAD, angiogenic factors could be explored as one of the new prognostic molecules. In recent studies, saliva and gingival crevicular fluid (GCF) have gained recognition as new, easily obtained diagnostic materials. This study aimed to compare the levels of selected circulating angiogenic factors (VEGF-A, PDGF-BB, and ANG-1) in unstimulated whole saliva (WS) and GCF versus plasma at three points in time to find possible correlations between their concentrations among patients with PAD and diabetes type 2 in 32 patients with Rutherford stages 5 and 6. A significant positive correlation has been demonstrated between circulating PDGF-BB levels in GCF and plasma. In most cases, comorbidities do not have an impact on the change in general correlation for the whole group. Our results clearly showed that GCF could be a good source for PDGF assessment. However, future studies with a larger number of subjects are warranted to confirm this finding and identify the most accurate angiogenic biomarkers in saliva or GCF that could be applied in clinical practice.

Current concepts in the pathogenesis of periodontitis: from symbiosis to dysbiosis

The primary etiological agent for the initiation and progression of periodontal disease is the dental plaque biofilm which is an organized aggregation of microorganisms residing within a complex intercellular matrix. The non-specific plaque hypothesis was the first attempt to explain the role of the dental biofilm in the pathogenesis of periodontal diseases. However, the introduction of sophisticated diagnostic and laboratory assays has led to the realisation that the development of periodontitis requires more than a mere increase in the biomass of dental plaque. Indeed, multispecies biofilms exhibit complex interactions between the bacteria and the host. In addition, not all resident microorganisms within the biofilm are pathogenic, since beneficial bacteria exist that serve to maintain a symbiotic relationship between the plaque microbiome and the host's immune-inflammatory response, preventing the emergence of pathogenic microorganisms and the development of dysbiosis. This review aims to highlight the development and structure of the dental plaque biofilm and to explore current literature on the transition from a healthy (symbiotic) to a diseased (dysbiotic) biofilm in periodontitis and the associated immune-inflammatory responses that drive periodontal tissue destruction and form mechanistic pathways that impact other systemic non-communicable diseases.

Saliva molecular testing bypassing RNA extraction is suitable for monitoring and diagnosing SARS-CoV-2 infection in children

Background

Adults are being vaccinated against SARS-CoV-2 worldwide, but the longitudinal protection of these vaccines is uncertain, given the ongoing appearance of SARS-CoV-2 variants. Children remain largely unvaccinated and are susceptible to infection, with studies reporting that they actively transmit the virus even when asymptomatic, thus affecting the community.

Methods

We investigated if saliva is an effective sample for detecting SARS-CoV-2 RNA and antibodies in children, and associated viral RNA levels to infectivity. For that, we used a saliva-based SARS-CoV-2 RT-qPCR test, preceded or not by RNA extraction, in 85 children aged 10 years and under, admitted to the hospital regardless of COVID-19 symptomatology. Amongst these, 29 (63.0%) presented at least one COVID-19 symptom, 46 (54.1%) were positive for SARS-CoV-2 infection, 28 (32.9%) were under the age of 1, and the mean (SD) age was 3.8 (3.4) years. Saliva samples were collected up to 48 h after a nasopharyngeal swab-RT-qPCR test.

Results

In children aged 10 years and under, the sensitivity, specificity, and accuracy of saliva-RT-qPCR tests compared to NP swab-RT-qPCR were, respectively, 84.8% (71.8%–92.4%), 100% (91.0%–100%), and 91.8% (84.0%–96.6%) with RNA extraction, and 81.8% (68.0%–90.5%), 100% (91.0%–100%), and 90.4% (82.1%–95.0%) without RNA extraction. Rescue of infectious particles from saliva was limited to CT values below 26. In addition, we found significant IgM positive responses to SARS-CoV-2 in children positive for SARS-CoV-2 by NP swab and negative by saliva compared to other groups, indicating late infection onset (>7–10 days).

Conclusions

Saliva is a suitable sample type for diagnosing children aged 10 years and under, including infants aged <1 year, even bypassing RNA extraction methods. Importantly, the detected viral RNA levels were significantly above the infectivity threshold in several samples. Further investigation is required to correlate SARS-CoV-2 RNA levels to viral transmission.

Immunoglobulin gene expression profiles and microbiome characteristics in periodontitis in nonhuman primates

Colonization of mucosal tissues throughout the body occurs by a wide array of bacteria in the microbiome that stimulate the cells and tissues, as well as respond to changes in the local milieu. A feature of periodontitis is the detection of adaptive immune responses to members of the oral microbiome that show specificity and changes with disease and treatment. Thus, variations in antibody responses are noted across the population and affected by aging, albeit, data are still unclear as to how these differences relate to disease risk and expression. This study used a nonhuman primate model of experimental periodontitis to track local microbiome changes as they related to the use and expression of a repertoire of immunoglobulin genes in gingival tissues. Gingival tissue biopsies from healthy tissues and following ligature-placement for disease initiation and progression provided gene expression analysis. Additionally, following removal of the ligatures, clinical healing occurs with gene expression in disease resolved tissues. Groups of 9 animals (young: <3 yrs., adolescent: 3-7 yrs., adult -12 to 15 yrs.; aged: 17-22 yrs) were used in the investigation. In healthy tissues, young and adolescent animals showed levels of expression of 78 Ig genes that were uniformly less than adults. In contrast, ⅔ of the Ig genes were elevated by > 2-fold in the aged samples. Specific increases in an array of the Ig gene transcripts were detected in adults at disease initiation and throughout progression, while increases in young and adolescent animals were observed only with disease progression, and in aged samples primarily late in disease progression. Resolved lesions continued to demonstrate elevated levels of Ig gene expression in only young, adolescent and adult animals. The array of Ig genes significantly correlated with inflammatory, tissue biology and hypoxia genes in the gingival tissues, with variations associated with age. In the young group of animals, specific members of the oral microbiome positively correlated with Ig gene expression, while in the older animals, many of these correlations were negative. Significant correlations were observed with a select assortment of bacterial OTUs and multiple Ig genes in both younger and older animal samples, albeit the genera/species showed little overlap. Incorporating this array of microbes and host responses clearly discriminated the various time points in transition from health to disease and resolution in both the young and adult animals. The results support a major importance of adaptive immune responses in the kinetics of periodontal lesion formation, and support aging effects on the repertoire of Ig genes that may relate to the increased prevalence and severity of periodontitis with age.

Gingival tissue antibody gene utilization in aging and periodontitis

OBJECTIVE

This study used a nonhuman primate model of ligature-induced periodontitis to document the characteristics of immunoglobulin (Ig) gene usage in gingival tissues with disease and affected by age.

BACKGROUND

Adaptive immune responses to an array of oral bacteria are routinely detected in local gingival tissues and the systemic circulation across the human population. The level and diversity of antibody increases with periodontitis, reflecting the increased quantity of B cells and plasmacytes in the tissues at sites of periodontal lesions.

METHODS

Macaca mulatta (n = 36) in four groups (young - ≤3 years; adolescent >3-7 years; adult - 12-15 years; aged - 17-23 years) were used in this study. Gingival tissues were sampled at baseline (health), 2 weeks (initiation), 1 and 3 months (progression), and 5 months (resolution) of the lesion development and transcriptomic analysis included 78 Ig-related genes.

RESULTS

The results demonstrated extensive variation in Ig gene usage patterns and changes with the disease process that was substantially affected by the age of the animal. Of note was that the aged animals generally demonstrated elevated expression on multiple Ig genes even in the baseline/healthy gingival tissues. The expression levels revealed 5 aggregates of Ig gene change profiles across the age groups. The number of gene changes were greatly increased in adult animals with the initiation of disease, while the young and adolescent animals showed extensive changes with disease progression. Elevated Ig gene transcripts remained with disease resolution except in the aged animals. The response profiles demonstrated selective heavy/light change gene transcripts that differed with age and clustering of the transcript expression was dominated by the age of the animals.

CONCLUSIONS

The results suggested potential critical variations in the molecular aspects of Ig gene expression in gingival tissues that can contribute to understanding the kinetics of periodontal lesions, as well as the variation in episodes, rapidity of progression, and role in resolution that are impacted by age.

Fixed Prosthetic Restorations and Periodontal Health: A Narrative Review

Periodontal health plays an important role in the longevity of prosthodontic restorations. The issues of comparative assessment of prosthetic constructions are complicated and not fully understood. The aim of this article is to review and present the current knowledge regarding the various technical, clinical, and molecular aspects of different prosthetic biomaterials and highlight the interactions between periodontal health and prosthetic restorations. Articles on periodontal health and fixed dental prostheses were searched using the keywords “zirconium”, “CAD/CAM”, “dental ceramics”, “metal–ceramics”, “margin fit”, “crown”, “fixed dental prostheses”, “periodontium”, and “margin gap” in PubMed/Medline, Scopus, Google Scholar, and Science Direct. Further search criteria included being published in English, and between January 1981 and September 2021. Then, relevant articles were selected, included, and critically analyzed in this review. The margin of discrepancy results in the enhanced accumulation of dental biofilm, microleakage, hypersensitivity, margin discoloration, increased gingival crevicular fluid flow (GCF), recurrent caries, pulp infection and, lastly, periodontal lesion and bone loss, which can lead to the failure of prosthetic treatment. Before starting prosthetic treatment, the condition of the periodontal tissues should be assessed for their oral hygiene status, and gingival and periodontal conditions. Zirconium-based restorations made from computer-aided design and computer-aided manufacturing (CAD/CAM) technology provide better results, in terms of marginal fit, inflammation reduction, maintenance, and the restoration of periodontal health and oral hygiene, compared to constructions made by conventional methods, and from other alloys. Compared to subgingival margins, supragingival margins offer better oral hygiene, which can be maintained and does not lead to secondary caries or periodontal disease.

A qualitative and quantitative analysis of the human gingival crevicular fluid proteome and metaproteome

Gingival crevicular fluid (GCF) is an integral part of oral fluid that plays a special role in maintaining the structure of junctional epithelium and defending against bacterial infection. In this study, we comprehensively analysed the composition of the human GCF proteome and metaproteome simultaneously to obtain multidimensional information about GCF. A total of 3680 human proteins (2540 with at least two unique peptides) were identified in the normal GCF sample, and their functions were mainly associated with immune function and inflammation. Among these proteins, 1874 proteins could be quantified by the iBAQ algorithm, and their abundances spanned a dynamic range of six orders of magnitude. For the GCF metaproteome, a total of 3082 proteins and 69 genera were found. In addition, 16 genera were not identified by GCF metagenomic analysis. Compared to the saliva metaproteome, 32 genera were found to be in common. The protein quantitative analysis showed that the abundance of GCF metaproteome contributed to approximately 4.17% of the total GCF proteome. The top three most abundant genera were Fusobacterium, Corynebacterium, and Leptotrichia. The above data will be useful for future research on GCF-related diseases.

Streptococcus mutans in atherosclerotic plaque: Molecular and immunohistochemical evaluations

OBJECTIVES

To verify the presence of Streptococcus mutans (S. mutans) in atherosclerotic plaque (AP) using techniques with different sensitivities, correlating with histological changes in plaque and immunoexpression of inflammatory markers.

MATERIALS AND METHODS

Thirteen AP samples were subjected to real-time polymerase chain reaction (qRT-PCR), histopathological analyses, histochemical analysis by Giemsa staining (GS), and immunohistochemical analysis for S. mutans, IL-1β, and TNF-α (streptavidin-biotin-peroxidase method). Ten necropsy samples of healthy vessels were used as controls.

RESULTS

All AP samples showed histopathological characteristics of severe atherosclerosis and were positive for S. mutans (100.0%) in qRT-PCR and immunohistochemical analyses. GS showed that Streptococcus sp. colonized the lipid-rich core regions and fibrous tissue, while the control group was negative for Streptococcus sp. IL-1β and TNF-α were expressed in 100% and 92.3% of the AP tested, respectively. The control samples were positive for S. mutans in qRT-PCR analysis, but negative for S. mutans, IL-1β, and TNF-α in immunohistochemical analyses.

CONCLUSION

The detection of S. mutans in AP and the visualization of Streptococcus sp. suggested a possible association between S. mutans and atherosclerosis. The results obtained from the control samples suggested the presence of DNA fragments or innocuous bacteria that were not associated with tissue alteration. However, future studies are necessary to provide more information.

Maintaining a protective state for human periodontal tissue

Periodontitis, caused by infection with periodontal pathogens, is primarily characterized by inflammatory bone resorption and destruction of connective tissue. Simply describing periodontitis as a specific bacterial infection cannot completely explain the various periodontal tissue destruction patterns observed. Periodontal tissue damage is thought to be caused by various factors. In recent years, research goals for periodontal pathogens have shifted from searching for specific pathogens to investigating mechanisms that damage periodontal tissues. Bacteria interact directly with the host in several ways, influencing expression and activity of molecules that evade host defenses, and destroying local tissues and inhibiting their repair. The host's innate and acquired immune systems are important defense mechanisms that protect periodontal tissues from attack and invasion of periodontal pathogens, thus preventing infection. Innate and acquired immunity have evolved to confront the microbial challenge, forming a seamless defense network in periodontal tissues. In the innate immune response, host cells quickly detect, via specialized receptors, macromolecules and nucleic acids present on bacterial cell walls, and this triggers a protective, inflammatory response. The work of this subsystem of host immunity is performed mainly by phagocytes, beta-defensin, and the complement system. In addition, the first line of defense in oral innate immunity is the junctional epithelium, which acts as a physical barrier to the entry of oral bacteria and other nonself substances. In the presence of a normal flora, junctional epithelial cells differentiate actively and proliferate apically, with concomitant increase in chemotactic factor expression recruiting neutrophils. These immune cells play an important role in maintaining homeostasis and the protective state in periodontal tissue because they eliminate unwanted bacteria over time. Previous studies indicate a mechanism for attracting immune cells to periodontal tissue with the purpose of maintaining a protective state; although this mechanism can function without bacteria, it is enhanced by the normal flora. A better understanding of the relationship between the protective state and its disruption in periodontal disease could lead to the development of new treatment strategies for periodontal disease.

Gingival transcriptomics of follicular T cell footprints in progressing periodontitis

Follicular helper T cells (Tfh) cells have been identified in the circulation and in tertiary lymphoid structures in chronic inflammation. Gingival tissues with periodontitis reflect chronic inflammation, so genomic footprints of Tfh cells should occur in these tissues and may differ related to aging effects. Macaca mulatta were used in a ligature-induced periodontitis model [adult group (aged 12-23 years); young group (aged 3-7 years)]. Gingival tissue and subgingival microbiome samples were obtained at matched healthy ligature-induced disease and clinical resolution sites. Microarray analysis examined Tfh genes (n = 54) related to microbiome characteristics documented using 16S MiSeq. An increase in the major transcription factor of Tfh cells, BCL6, was found with disease in both adult and young animals, while master transcription markers of other T cell subsets were either decreased or showed minimal change. Multiple Tfh-related genes, including surface receptors and transcription factors, were also significantly increased during disease. Specific microbiome patterns were significantly associated with profiles indicative of an increased presence/function of Tfh cells. Importantly, unique microbial complexes showed distinctive patterns of interaction with Tfh genes differing in health and disease and with the age of the animals. An increase in Tfh cell responsiveness occurred in the progression of periodontitis, affected by age and related to specific microbial complexes in the oral microbiome. The capacity of gingival Tfh cells to contribute to localized B cell activation and active antibody responses, including affinity maturation, may be critical for controlling periodontal lesions and contributing to limiting and/or resolving the lesions.

Role of Periodontal Infection, Inflammation and Immunity in Atherosclerosis

BACKGROUND

Inflammation plays a major role in the development and progression of cardiovascular disease (CVD) morbidity and mortality. The well-established relationship between periodontal disease (PD) and CVD may be causal. Left untreated, PD can lead to high systemic inflammation, thus contributing to inflammatory CVD, such as atherosclerosis. Multiple mechanisms have been proposed to elucidate the causal relationship between PD and its contribution to CVD.

OBJECTIVE

This review article highlights the current evidence supporting the role of PD in the development and progression of atherosclerosis.

METHODS

After creating a list of relevant medical subject heading (MeSH) terms, a systematic search within PubMed in English for each MeSH term between 2000 and 2019 was used to generate evidence for this review article.

CONCLUSION

There is overwhelming evidence in the current literature that supports an association between PD and CVD that is independent of known CVD risk factors. However, the supporting evidence that PD directly causes CVD in humans continues to remain elusive. Multiple biologically plausible mechanisms have been proposed and investigated, yet most studies are limited to mouse models and in vitro cell cultures. Additional studies testing the various proposed mechanisms in longitudinal human studies are required to provide deeper insight into the mechanistic link between these 2 related diseases.

Association of Oral Hygiene and Periodontal Health with Third Molar Pericoronitis: A Cross-Sectional Study

Background

Pericoronitis is a painful inflammatory condition commonly associated with third molar teeth. The purpose of this study was to investigate the relationship between oral hygiene and periodontal health status and the presence of pericoronitis in semi-impacted third molar teeth.

Methods

A cross-sectional study was conducted, and 54 patients having at least one mandibular vertically semi-impacted third molar tooth with or without pericoronitis were consecutively enrolled. Subjects with pericoronitis and subjects with healthy third molars were selected according to symptoms in the gingiva overlying semi-impacted third molar teeth. Periodontal health status and oral hygiene were evaluated with the measures of plaque index (PI), gingival index (GI), and total number of sites with a probing depth (PD) ≥ 4 mm. The clinical data collected in this study was analyzed with Mann–Whitney U test using SPSS 20.0 package program.

Results

The PI scores were found to be significantly higher in patients with pericoronitis (p < 0.05). Although the GI scores and PD scores were higher in patients with pericoronitis, the difference did not reach statistical significance when compared with those in healthy subjects (p > 0.05).

Conclusion

The findings obtained in this study suggest that the amount of dental plaque was positively associated with third molar pericoronitis. Gingival and periodontal health conditions were similar between patients with and without pericoronitis. Improving oral hygiene and controlling dental plaque may help prevent third molar pericoronitis.

Gingival Crevicular Fluid (GCF): A Diagnostic Tool for the Detection of Periodontal Health and Diseases

The methodologies applicable for the evaluation of periodontal associated diseases are constantly evolving to provide quick, realistic, and scientifically proven results. Trends in the past followed a clinical evaluation of periodontal tissues and radiographic-based reports that formed the foundation for detection of diseases involving the structures supporting the teeth. As the confines and limitations of conventional strategies became obvious over the passage of time, hand in hand variety of techniques have evolved and experimentally justified. These improvisations are based on an improved understanding of the periodontal-pathogenic cascade. Periodontal pathogenesis and a paradigm shift from disease understanding to disease prevention and treatment entail few prerequisites that demand the objectivity of diagnostics procedure that includes sensitivity and specificity along with an explanation of the intensity of the disease, Gingival crevicular fluid an oral bio-fluid resides in the close proximity with gingival tissues have been widely used to understand and differentiate the periodontal health and diseased status. The biomarkers present in the GCF can be a reliable tool to detect the minute changes seen in the disease processes. The GCF consists of various host and bacterial-derived products as well as biomarkers which in turn can be evaluated for the diagnosis, prognosis as well as management of the periodontal disease. Thus, the review aims at describing GCF as a potential oral biofluid helpful in differentiating periodontal health and disease status.

Cytomorphometric Analysis of Inflammation Dynamics in the Periodontium Following the Use of Fixed Dental Prostheses

Cytomorphometry is used in the sampling of biological materials and diagnostic procedures. The use of cytological studies in periodontal diseases is not well described in the literature. Our study aimed to quantitatively assess the inflammation dynamics using cytomorphometric analysis of the periodontium before and after the use of fixed dental prostheses. Following ethics approval, a total of 105 subjects were divided in 3 groups as gingivitis (n = 23), periodontitis (n = 58), and healthy periodontium (control) (n = 24). The fixed dental prostheses (crowns and fixed partial dentures) were fabricated from cobalt-chrome metal-ceramic prostheses using the conventional method (C/M-CoCr), cobalt-chrome metal-ceramic prostheses by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (C/C-CoCr), and zirconia-based ceramic prostheses by the CAD/CAM technique (C/C-Zr) among subjects with gingivitis and periodontitis. The gingival crevicular fluid (GCF) was obtained from subjects before and after the use of the prostheses. The total count of epithelial cells and the connective tissue cells or polymorphonuclear neutrophils (PMNs) in GCF were studied using cytomorphometric analysis. The Statistical Package Tor the Social Sciences (SPSS), Version 20 (IBM Company, Chicago, IL, USA) was used to analyze the results and the significance level was set at p = 0.05. The data for before and after the use of the prostheses were compared using independent t-Tests. Similarly, the results after the use of prostheses in gingivitis, periodontitis, and control in each type of prostheses were compared using One-way ANOVA with post hoc using Scheffe. The total epithelial cells and the PMNs were determined along with the epithelium/leukocyte index. Regardless of the prostheses type used, no significant change in the parameters was identified among patients with a healthy periodontium, before and after prosthetic treatment. In all study groups, a statistically increase (p value < 0.05) was observed in the oral epithelial cell counts and a statistically decrease (p < 0.05) in the PMNs count following the use of the fixed prostheses. Data on cytomorphometric analysis could enable the selection of the most appropriate prostheses for use in patients with periodontal pathologies. When choosing prostheses, changes in the composition of GCF could be considered as a useful criterion for their use.

Periodontitis and the impact of oral health on the quality of life of psoriatic individuals: a case-control study

AIM

To evaluate the periodontal condition and the impact of oral health on the quality of life (OHRQL) among individuals with and without psoriasis.

METHODS

This case-control study comprised 295 individuals with psoriasis and 359 controls. A full mouth examination was performed for all periodontal clinical parameters. To evaluate OHRQL, the Oral Impact on Daily Performance (OIDP) questionnaire was applied. Data was analyzed using the chi-square, Fischer, Kruskal-Wallis, Mann-Whitney, and Bootstrap intervals tests to determine different profiles in relation to the OIDP.

RESULTS

Individuals with psoriasis had a 1.40 greater chance of having periodontitis than controls (OR = 1.40 95%CI: 1.01-1.93; p = 0.019). Individuals with psoriasis with periodontitis (+P) had greater impacts on OHRQL (13.76 ± 15.58), when compared with those without periodontitis (-P) (4.83 ± 8.25; p < 0.001). Additionally, psoriasis +P stage III/IV patients (13.94 ± 15.68) had worse indicators than controls -P (9.49 ± 22.54; p = 0.001). The final multivariate model demonstrated higher OIDP scores related to the following variables: diabetes, anxiolytics use, periodontitis, and psoriasis, showing worse OHRQoL.

CONCLUSIONS

This study demonstrated an important risk association between psoriasis and periodontitis, as both diseases demonstrated worse OHRQL indicators. Moreover, the severity of periodontitis and psoriasis significantly increased these negative impacts.

CLINICAL RELEVANCE

Practical implications: Multidisciplinary interaction is desirable to improve the impact of these diseases on the QoL of individuals with psoriasis and periodontitis.

Levels of Interleukin-6 in Saliva, but Not Plasma, Correlate with Clinical Metrics in Huntington's Disease Patients and Healthy Control Subjects

Growing evidence suggests that inflammatory responses, in both the brain and peripheral tissues, contribute to disease pathology in Huntington's disease (HD), an inherited, progressive neurodegenerative disorder typically affecting adults in their 30-40 s. Hence, studies of inflammation-related markers in peripheral fluids might be useful to better characterize disease features. In this study, we measured levels of C-reactive protein (CRP), Interleukin-6 (IL-6), interleukin 1 beta (IL-1B), and alpha-amylase (AA) in saliva and plasma from n = 125 subjects, including n = 37 manifest HD patients, n = 36 premanifest patients, and n = 52 healthy controls, using immunoassays. We found increases in salivary levels of IL-6, IL-1B and CRP across different disease groups and increased levels of IL-6 in the plasma of HD patients as compared to premanifest patients and controls. The levels of salivary IL-6 were significantly correlated with each of the other salivary markers, as well as with IL-6 levels measured in plasma. Further, salivary IL-6 and IL-1B levels were significantly positively correlated with Total Motor Score (TMS) and chorea scores and negatively correlated with Total Functional Capacity (TFC) in HD patients, whereby in healthy control subjects, IL-6 was significantly negatively correlated with Montreal Cognitive Assessment (MoCA) and the Symbol Digit Modalities test (SDM). Interestingly, the plasma levels of IL-6 did not show similar correlations to any clinical measures in either HD or control subjects. These findings suggest that salivary IL-6 is particularly relevant as a potential non-invasive biomarker for HD symptoms. The advent of an effective, dependable salivary biomarker would meet the urgent need for a less invasive means of identifying and monitoring HD disease progression.

Evaluation of the In Vitro Oral Wound Healing Effects of Pomegranate (Punica granatum) Rind Extract and Punicalagin, in Combination with Zn (II)

Pomegranate (Punica granatum) is a well-established folklore medicine, demonstrating benefits in treating numerous conditions partly due to its antimicrobial and anti-inflammatory properties. Such desirable medicinal capabilities are attributed to a high hydrolysable tannin content, especially punicalagin. However, few studies have evaluated the abilities of pomegranate to promote oral healing, during situations such as periodontal disease or trauma. Therefore, this study evaluated the antioxidant and in vitro gingival wound healing effects of pomegranate rind extract (PRE) and punicalagin, alone and in combination with Zn (II). In vitro antioxidant activities were studied using DPPH and ABTS assays, with total PRE phenolic content measured by Folin-Ciocalteu assay. PRE, punicalagin and Zn (II) combination effects on human gingival fibroblast viability/proliferation and migration were investigated by MTT assay and scratch wounds, respectively. Punicalagin demonstrated superior antioxidant capacities to PRE, although Zn (II) exerted no additional influences. PRE, punicalagin and Zn (II) reduced gingival fibroblast viability and migration at high concentrations, but retained viability at lower concentrations without Zn (II). Fibroblast speed and distance travelled during migration were also enhanced by punicalagin with Zn (II) at low concentrations. Therefore, punicalagin in combination with Zn (II) may promote certain anti-inflammatory and fibroblast responses to aid oral healing.

Heterogeneity of human serum antibody responses to P. gingivalis in periodontitis: Effects of age, race/ethnicity, and sex

Aging humans display an increased prevalence and severity of periodontitis, although the mechanisms underlying these findings remain poorly understood. This report examined antigenic diversity of P. gingivalis related to disease presence and patient demographics. Serum IgG antibody to P. gingivalis strains ATCC33277, FDC381, W50 (ATCC53978), W83, A7A1-28 (ATCC53977) and A7436 was measured in 426 participants [periodontally healthy (n = 61), gingivitis (N = 66) or various levels of periodontitis (N = 299)]. We hypothesized that antigenic diversity in P. gingivalis could contribute to a lack of "immunity" in the chronic infections of periodontal disease. Across the strains, the antibody levels in the oldest age group were lower than in the youngest groups, and severe periodontitis patients did not show higher antibody with aging. While 80 % of the periodontitis patients in any age group showed an elevated response to at least one of the P. gingivalis strains, the patterns of individual responses in the older group were also substantially different than the other age groups. Significantly greater numbers of older patients showed strain-specific antibody profiles to only 1 strain. The findings support that P. gingivalis may demonstrate antigenic diversity/drift within patients and could be one factor to help explain the inefficiency/ineffectiveness of the adaptive immune response in managing the infection.

Salivary total Immunoglobulin G as a surrogate marker of oral immune activity in salivary bioscience research

The integration of salivary biomeasures in biobehavioral, psychophysiological, and clinical research has greatly expanded our ability to study the biopsychosocial processes underlying health. Much of this research, however, has failed to adequately assess and adjust for the impact of oral immune activity on salivary biomeasure concentrations and associations with serum levels. Aiming to improve the validity and reliability of salivary biomeasure data, we examine salivary total Immunoglobulin G (IgG) as a potential surrogate marker of oral inflammation and immune activity. During a single study visit in Baltimore, Maryland, healthy young adult participants provided matched blood and saliva samples (N=99; age 18-37 years, 42% female) and completed an oral health questionnaire. Biospecimens were assayed for total IgG and immune markers related to inflammation (cytokines), blood in saliva (transferrin), and tissue remodeling (matrix metalloproteinase-8). Total IgG (μg/mL) concentrations were higher in serum than saliva. Salivary total IgG was associated with some self-reported oral health measures, and strongly positively associated with all salivary immune markers. Controlling for salivary total IgG may be a feasible, affordable approach to adjusting salivary biomeasure findings for the influence of the oral immune environment when it is not possible or practical to obtain clinical oral health data.

Biomarkers of oral inflammation in perinatally HIV-infected and perinatally HIV-exposed, uninfected youth

AIM

To examine oral biomarkers that have been associated with periodontal disease progression in HIV-infected adults in perinatally HIV-infected and HIV-exposed but uninfected youth.

MATERIAL AND METHODS

This was a cross-sectional, multicentre substudy of youth participating in the Oral Health Pediatric HIV/AIDS Cohort study. Gingival crevicular fluid repository samples from participants with and without periodontal disease (using Gingival Index [GI] and Bleeding on Probing [BOP] parameters on dental examination) were tested for concentration levels of inflammatory biomarkers. Associations were assessed using Wilcoxon test and Spearman correlation.

RESULTS

For perinatal HIV youth (n = 129), the markers consistently elevated (p < .05) in sites with GI ≥2 and in sites with BOP were interleukin-1β, 6 and 13, macrophage inflammatory protein-1α and metalloproteinase-9. Serum tumour necrosis factor-α and soluble CD14 were positively correlated with a summary count of elevated cytokines. No associations were seen among HIV-uninfected subjects (n = 71).

CONCLUSIONS

The association of oral biomarkers of inflammation with clinical indicators of periodontal inflammation and systemic immune activation suggests that perinatal HIV-infected youth may be at higher risk for developing significant periodontal disease, associated with tooth loss and HIV progression. More frequent dental care of this group is needed to prevent potential periodontal progression.

Age and Periodontal Health - Immunological View

PURPOSE OF THE REVIEW

Aging clearly impacts a wide array of systems, in particular the breadth of the immune system leading to immunosenescence, altered immunoactivation, and coincident inflammaging processes. The net result of these changes leads to increased susceptibility to infections, increased neoplastic occurrences, and elevated frequency of autoimmune diseases with aging. However, as the bacteria in the oral microbiome that contribute to the chronic infection of periodontitis is acquired earlier in life, the characteristics of the innate and adaptive immune systems to regulate these members of the autochthonous microbiota across the lifespan remains ill defined.

RECENT FINDINGS

Clear data demonstrate that both cells and molecules of the innate and adaptive immune response are adversely impacted by aging, including in the oral cavity, yielding a reasonable tenet that the increased periodontitis noted in aging populations is reflective of the age-associated immune dysregulation. Additionally, this facet of host-microbe interactions and disease needs to accommodate the population variation in disease onset and progression, which may also reflect an accumulation of environmental stressors and/or decreased protective nutrients that could function at the gene level (ie. epigenetic) or translational level for production and secretion of immune system molecules.

SUMMARY

Finally, the majority of studies of aging and periodontitis have emphasized the increased prevalence/severity of disease with aging, all based upon chronological age. However, evolving areas of study focusing on "biological aging" to help account for population variation in disease expression, may suggest that chronic periodontitis represents a co-morbidity that contributes to "gerovulnerability" within the population.

Inhibition of osteoclastogenesis by opsonized Porphyromonas gingivalis

A crucial step in the pathogenesis of periodontal disease (PD) is activation of osteoclasts (OC) by numerous virulence factors produced by Porphyromonas gingivalis (Pg). To understand pathogenesis of PD and the role of specific adaptive immune responses, effects of antibodies on Pg‐induced OC differentiation and function were investigated. Human peripheral blood‐derived monocytes were differentiated to OC in the presence or absence of: (a) Pg; (b) antibodies to Pg; and (c) antibody‐opsonized Pg. Findings suggest significant induction of osteoclastogenesis by Pg when compared to control cultures, whereas opsonization decreased osteoclastogenesis by 45%. Immune receptor gene expression profile in the presence of opsonized Pg showed marked upregulation of TLR1 (three‐fold) and TLR2 (twofold) along with FcγRIIB (two‐fold) and FcγRIII receptors (five‐fold), but not TLR4 and FcRγ receptors. Interestingly, blocking FcγRIIB, but not FcγRIII receptor, reversed the inhibitory effects of opsonized Pg suggesting a critical role played by FcγRIIB in osteoclastogenesis. Furthermore, opsonized Pg transformed OC precursors to a “macrophage phenotype” suggesting a bone protective role of the immune complexes in modulating osteoclastogenesis, probably by competing as an agonist for pattern recognition receptors, and inducing selective activation of FcγRs with simultaneous suppression of FcRγ which regulates bone resorptive process. Further defining effective antibody isotypes, avidity, and antigenic specificity could improve targets for eliciting protective immunity.

Dental biofilm: ecological interactions in health and disease

BACKGROUND

The oral microbiome is diverse and exists as multispecies microbial communities on oral surfaces in structurally and functionally organized biofilms.

AIM

To describe the network of microbial interactions (both synergistic and antagonistic) occurring within these biofilms and assess their role in oral health and dental disease.

METHODS

PubMed database was searched for studies on microbial ecological interactions in dental biofilms. The search results did not lend themselves to systematic review and have been summarized in a narrative review instead.

RESULTS

Five hundred and forty-seven original research articles and 212 reviews were identified. The majority (86%) of research articles addressed bacterial-bacterial interactions, while inter-kingdom microbial interactions were the least studied. The interactions included physical and nutritional synergistic associations, antagonism, cell-to-cell communication and gene transfer.

CONCLUSIONS

Oral microbial communities display emergent properties that cannot be inferred from studies of single species. Individual organisms grow in environments they would not tolerate in pure culture. The networks of multiple synergistic and antagonistic interactions generate microbial inter-dependencies and give biofilms a resilience to minor environmental perturbations, and this contributes to oral health. If key environmental pressures exceed thresholds associated with health, then the competitiveness among oral microorganisms is altered and dysbiosis can occur, increasing the risk of dental disease.

Ageing effects on humoral immune responses in chronic periodontitis

Periodontal disease is a dominant global bacterial infection that increases with ageing.

AIM

This report focuses on host adaptive immune responses in periodontitis. While experimental models and humans diagnosed with periodontitis demonstrate an antigenic specificity for particular oral bacteria, we have a limited understanding of (i) how ageing affects the adaptive immune responses to these bacteria that chronically colonize the oral cavity for decades prior to disease expression and (ii) how the magnitude and specificity of the response interface with pathogens that emerge within the bacterial ecology during exacerbations of disease.

MATERIALS AND METHODS

Serum antibody levels to a group of pathogenic and commensal oral bacteria were measured in a population of individuals from 21 to 74 years of age, stratified based on clinical status of the periodontium, smoking and sex.

RESULTS

Clinical parameters were not significantly different within health, gingivitis or periodontitis groups related to age. Antibody to oral pathogens and commensals was similar in different age groups in each of the clinical categories, with no age correlation noted in the periodontitis patients.

CONCLUSIONS

The adaptive immune responses to oral bacteria that chronically colonize the oral cavity appear generally unaffected by age, but clearly are linked to the extent of disease.

The periodontal pocket

Periodontal disease is synonymous with the presence of periodontal pockets, and very often the clinical success of periodontal therapy is based on periodontal pocket depth reduction. Therefore, in the fields of periodontology and implant dentistry, significant research effort has been placed on the etiopathogenesis, diagnosis and treatment of periodontal/peri-implant disease and as a consequence on pocket pathology. In this volume of Periodontology 2000, the in-depth reviews include topics ranging from preclinical models, anatomy and structure of tissues, and molecular and bacterial components, to treatments of pockets around teeth and implants. These reviews aim to provide the readers with current and future perspectives on the different areas of research into the periodontal pocket.

The effect of restorative materials on cytokines in gingival crevicular fluid

OBJECTIVE

Composition of the restorative materials may cause inflammatory responses by monocyte activation and changes in the levels of cytokine released from different cells. Interleukin-6 (IL-6), interleukin-8 (IL-8) and Tumor necrosis factor alpha (TNF-α) are important cytokine for evaluating of the inflammatory process. The aim of this study was to evaluate the different restorative materials used in class V cavities effect on gingival crevicular fluid inflammatory cytokine levels.

DESIGN

60 individuals having Class V carious cavities participated in the study. Cavities were restored with FiltekZ250, DyractXP, Fuji IX, Cavex avalloy restorative materials. Changes in clinical and biochemical parameters were evaluated before restorations, seven and 21days after restorations. Contralateral tooth intact enamel surface was determined as control side. Periotron8000 device was used for detection of GCF volume. Cytokine level of GCF was evaluated by Human ELISA kits. Data were analyzed using Mann-Whitney U test and Wilcoxon signed ranks test. The correlations between clinical parameters and biochemical parameters were examined by Spearman's rank correlation analysis.

RESULTS

After restorative treatments PI and GI scores were decreased compared with baseline evaluations. There was a significant difference in GCF levels between experimental and control sites in all groups. GCF IL-6 levels in all groups except Filtek Z250, GCF IL-8 levels in all groups except Fuji IX, GCF TNF-α level in only Fuji IX showed significant differences between experimental and control sites.

CONCLUSIONS

The obtained data supported that all of the tested materials caused changes in GCF cytokine levels.

The Immune Response in Periodontal Tissues

The uniqueness of periodontal diseases is caused by several factors. This group of diseases is caused by numerous bacterial species formed in the dental biofilm, and one cannot distinguish the specific pathogen that is responsible for the disease initiation or progress (though Gram-negative anaerobic rods are associated with the advanced form of the disease). The disease is both infectious and inflammatory in its nature, and in the state of health there is always a subclinical level of inflammatory response, caused by the so-called harmless bacteria. Negligence in oral hygiene may result in maturation of the biofilm and trigger host response, manifesting clinically as gingivitis or-later and in susceptible subjects-as periodontitis. The article presents the contemporary knowledge of the inflammatory reaction occurring in tissues surrounding the tooth during periodontal inflammation. The most important mechanisms are described, together with implications for clinicists.

Periodontitis and risk of psoriasis: a systematic review and meta-analysis

BACKGROUND

The association between periodontitis and systemic diseases has been increasingly recognized. However, the data on the association between periodontitis and psoriasis are still limited.

OBJECTIVES

To summarize all available data on the association between periodontitis and the risk of psoriasis.

METHODS

Two investigators independently searched published studies indexed in MEDLINE and EMBASE databases from inception to July 2016 using a search strategy that included terms for psoriasis and periodontitis. Studies were included if the following criteria were met: (i) case-control or cohort study comparing the risk of psoriasis in subjects with and without periodontitis; (ii) subjects without periodontitis were used as comparators in cohort studies while participants without psoriasis were used as controls in case-control studies; and (iii) effect estimates and 95% confidence intervals (CI) were provided. Point estimates and standard errors from each study were extracted and combined together using the generic inverse variance technique described by DerSimonian and Laird.

RESULTS

Two cohort studies and three case-control studies met the inclusion criteria and were included in the meta-analysis. The pooled risk ratio of psoriasis in patients with periodontitis versus comparators was 1.55 (95% CI, 1.35-1.77). The statistical heterogeneity was insignificant with an I2 of 18%. Subgroup analysis according to study design revealed a significantly higher risk among patients with periodontitis with a pooled RR of 1.50 (95% CI, 1.37-1.64) for cohort studies and a pooled RR of 2.33 (95% CI, 1.51-3.60) for case-control studies.

CONCLUSIONS

Patients with periodontitis have a significantly elevated risk of psoriasis.

Association Between Asthma and Periodontitis: Results From the Korean National Health and Nutrition Examination Survey

BACKGROUND

The aim of this study is to examine the association between asthma and periodontitis in a representative sample of Korean adults from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES) in 2014.

METHODS

This study conducts a cross-sectional evaluation using 2014 KNHANES data to describe the association between current asthma condition and chronic periodontitis while adjusting for sociodemographic characteristics and lifestyle factors. Presence of periodontitis is evaluated by community periodontal index defined by the World Health Organization, and current asthma condition is defined as "currently suffering from asthma condition."

RESULTS

The study population comprises a total of 5,976 patients aged 19 years and older, representing 40.7 million Koreans. A multivariable logistic regression analysis with weighted observations reveals patients with current asthma condition are ≈5 times more likely to be associated with periodontitis (adjusted odds ratio [OR]: 5.36; 95% confidence interval [95% CI]: 1.27 to 22.68). In addition, 83% of patients who regularly receive scheduled antiasthmatic medications are less likely to have a diagnosis of periodontitis than individuals who do not receive medication regularly (adjusted OR: 0.17; 95% CI: 0.05 to 0.57). However, the association is not significant if treatment with antiasthmatic medication is delivered on an "as-needed" basis (adjusted OR:1.80; 95% CI: 0.87 to 3.74).

CONCLUSIONS

Findings from the current study show a positive association between periodontitis and current asthma condition. In addition, patients taking scheduled antiasthmatic medications are less likely to be diagnosed with periodontitis. Due to limitations of study design and available data from the national survey, well-designed follow-up studies are needed to confirm these findings.

Cross-talk between clinical and host-response parameters of periodontitis in smokers

BACKGROUND AND OBJECTIVE

Periodontal diseases are a major public health concern leading to tooth loss and have also been shown to be associated with several chronic systemic diseases. Smoking is a major risk factor for the development of numerous systemic diseases, as well as periodontitis. While it is clear that smokers have a significantly enhanced risk for developing periodontitis leading to tooth loss, the population varies regarding susceptibility to disease associated with smoking. This investigation focused on identifying differences in four broad sets of variables, consisting of: (i) host-response molecules; (ii) periodontal clinical parameters; (iii) antibody responses to periodontal pathogens and oral commensal bacteria; and (iv) other variables of interest, in a population of smokers with (n = 171) and without (n = 117) periodontitis.

MATERIAL AND METHODS

Bayesian network structured learning (BNSL) techniques were used to investigate potential associations and cross-talk between the four broad sets of variables.

RESULTS

BNSL revealed two broad communities with markedly different topology between the populations of smokers, with and without periodontitis. Confidence of the edges in the resulting network also showed marked variations within and between the periodontitis and nonperiodontitis groups.

CONCLUSION

The results presented validated known associations and discovered new ones with minimal precedence that may warrant further investigation and novel hypothesis generation. Cross-talk between the clinical variables and antibody profiles of bacteria were especially pronounced in the case of periodontitis and were mediated by the antibody response profile to Porphyromonas gingivalis.

Transcriptome Analysis of B Cell Immune Functions in Periodontitis: Mucosal Tissue Responses to the Oral Microbiome in Aging

Evidence has shown activation of T and B cells in gingival tissues in experimental models and in humans diagnosed with periodontitis. The results of this adaptive immune response are noted both locally and systemically with antigenic specificity for an array of oral bacteria, including periodontopathic species, e.g., Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. It has been recognized through epidemiological studies and clinical observations that the prevalence of periodontitis increases with age. This report describes our studies evaluating gingival tissue transcriptomes in humans and specifically exploiting the use of a non-human primate model of naturally occurring periodontitis to delineate gingival mucosal tissue gene expression profiles focusing on cells/genes critical for the development of humoral adaptive immune responses. Patterns of B cell and plasmacyte genes were altered in aging healthy gingival tissues. Substantial increases in a large number of genes reflecting antigen-dependent activation, B cell activation, B cell proliferation, and B cell differentiation/maturation were observed in periodontitis in adults and aged animals. Finally, evaluation of the relationship of these gene expression patterns with those of various tissue destructive molecules (MMP2, MMP9, CTSK, TNFα, and RANKL) showed a greater frequency of positive correlations in healthy tissues versus periodontitis tissues, with only MMP9 correlations similar between the two tissue types. These results are consistent with B cell response activities in healthy tissues potentially contributing to muting the effects of the tissue destructive biomolecules, whereas with periodontitis this relationship is adversely affected and enabling a progression of tissue destructive events.

Increased levels of interleukin-33 in gingival crevicular fluids of patients with chronic periodontitis

The purpose of this clinical study is to comparatively investigate the interleukin-33 (IL-33) levels in gingival crevicular fluid (GCF), saliva and plasma of patients with periodontal disease as well as periodontally healthy subjects and the association between these levels and clinical parameters. GCF, saliva and plasma samples were collected from systemically healthy, non-smoker chronic periodontitis patients (CP group, n = 20), gingivitis patients (G group, n = 20) and periodontally healthy control groups (H group, n = 20). Full-mouth clinical periodontal parameters were also recorded. IL-33 levels were determined by ELISA. The total amount of GCF IL-33 was greater in the G and CP groups compared to the H group (p < 0.05). The GCF IL-33 concentration was significantly lower in the CP group than in the H and G groups (p < 0.001). Salivary or plasma IL-33 levels were similar in the study groups. The total amount of GCF IL-33 was positively correlated with the GI, PI and BOP (%) (p < 0.05). Considering the present findings, the increase in total amounts of GCF IL-33 may have a role in the pathogenesis of periodontal disease.

The Burden of Oral Disease among Perinatally HIV-Infected and HIV-Exposed Uninfected Youth

Objective

To compare oral health parameters in perinatally HIV-infected (PHIV) and perinatally HIV-exposed but uninfected youth (PHEU).

Methods

In a cross-sectional substudy within the Pediatric HIV/AIDS Cohort Study, participants were examined for number of decayed teeth (DT), Decayed, Missing, and Filled Teeth (DMFT), oral mucosal disease, and periodontal disease (PD). Covariates for oral health parameters were examined using zero-inflated negative binomial regression and ordinal logistic regression models.

Results

Eleven sites enrolled 209 PHIV and 126 PHEU. Higher DT scores were observed in participants who were PHIV [Adjusted Mean Ratio (aMR) = 1.7 (95% CI 1.2–2.5)], female [aMR = 1.4 (1.0–1.9)], had no source of regular dental care [aMR = 2.3 (1.5–3.4)], and had a high frequency of meals/snacks [≥5 /day vs 0–3, aMR = 1.9 (1.1–3.1)] and juice/soda [≥5 /day vs 0–3, aMR = 1.6 (1.1–2.4)]. Higher DMFT scores were observed in participants who were older [≥19, aMR = 1.9 (1.2–2.9)], had biological parent as caregiver [aMR = 1.2 (1.0–1.3)], had a high frequency of juice/soda [≥5 /day vs 0–3, aMR = 1.4 (1.1–1.7)] and a low saliva flow rate [mL/min, aMR = 0.8 per unit higher (0.6–1.0)]. Eighty percent had PD; no differences were seen by HIV status using the patient-based classifications of health, gingivitis or mild, moderate, or severe periodontitis. No associations were observed of CD4 count and viral load with oral health outcomes after adjustment.

Conclusions

Oral health was poor in PHIV and PHEU youth. This was dismaying since most HIV infected children in the U.S. are carefully followed at medical health care clinics. This data underscore the need for regular dental care. As PHIV youth were at higher risk for cavities, it will be important to better understand this relationship in order to develop targeted interventions.

Analysis of matrix metalloproteinase-8 levels in gingival crevicular fluid and whole mouth fluid among smokers and nonsmokers using enzyme-linked immune-sorbent assay and a novel chair-side test

AIM

To indigenously prepare a chair-side test kit for investigating and comparing the matrix metalloproteinase (MMP)-8 levels in gingival crevicular fluid (GCF) and saliva in patients with healthy periodontium, gingivitis and chronic periodontitis in smokers and nonsmokers. To validate the diagnostic accuracy of indigenously prepared chair-side test against enzyme-linked immune-sorbent assay (ELISA). Furthermore, to assess the effect of nonsurgical periodontal therapy (NSPT) on the levels of MMP-8 in GCF and saliva among the test groups.

MATERIALS AND METHODS

GCF and saliva were collected from 250 subjects. The study population were divided into five groups; health periodontium-nonsmokers (Group 1; n = 50), chronic gingivitis-nonsmokers (Group 2; n = 50), chronic periodontitis-nonsmokers (Group 3; n = 50), chronic gingivitis-smokers (Group 4; n = 50), chronic periodontitis-smokers (Group 5; n = 50). A chair-side test kit was indigenously prepared using polyclonal antibodies (principle of immunochromatography) to detect the MMP-8 levels, and it was validated against ELISA at baseline and 3 months after NSPT.

RESULTS

The chair-side test detected MMP-8 levels with a sensitivity and specificity in accordance with ELISA. MMP-8 levels at baseline were higher in Group 2 and Group 3 as compared to controls (P < 0.05), and decreased after therapy (P < 0.05). MMP-8 levels in GCF were greater than in saliva for all the groups, indicating GCF to be a better sample to detect the MMP levels.

CONCLUSION

The chair-side test detected MMP-8 levels accurately making it a viable chair side diagnostic tool. It was effective for early diagnosis of the periodontal disease among high-risk population such as smokers.

Biology and pathogenesis of cytomegalovirus in periodontal disease

Human periodontitis is associated with a wide range of bacteria and viruses and with complex innate and adaptive immune responses. Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, Treponema denticola, cytomegalovirus and other herpesviruses are major suspected pathogens of periodontitis, and a combined herpesvirus–bacterial periodontal infection can potentially explain major clinical features of the disease. Cytomegalovirus infects periodontal macrophages and T‐cells and elicits a release of interleukin‐1β and tumor necrosis factor‐α. These proinflammatory cytokines play an important role in the host defense against the virus, but they also have the potential to induce alveolar bone resorption and loss of periodontal ligament. Gingival fibroblasts infected with cytomegalovirus also exhibit diminished collagen production and release of an increased level of matrix metalloproteinases. This article reviews innate and adaptive immunity to cytomegalovirus and suggests that immune responses towards cytomegalovirus can play roles in controlling, as well as in exacerbating, destructive periodontal disease.

Slow and fast orthodontic tooth movement: an experimental study on humans

INTRODUCTION

The aim of this study was to investigate the variation in the amount of the orthodontically induced tooth movement in humans and potential associations between the amount of tooth movement with age and location in the mandible or maxilla.

SUBJECTS AND METHODS

This study included 11 participants (7 females, 4 males) with an age range of 11.3-28.6 years. In a standardized experimental orthodontic tooth movement protocol, two premolars of each participant were moved buccally during 8 weeks with the use of 1 N force. No functional or localized obstacles were affecting the displacement. Plaster models before and after the experimental tooth movement were constructed, digitized, and superimposed, to evaluate the amount of tooth movement of each tooth. Random effects linear regression analysis was performed to examine associations between tooth displacement, age, and tooth location.

RESULTS

The mean displacement of the teeth was 2.7±1.4mm. The range of tooth movement varied substantially between individuals (0.6-5.8mm). The displacement of the teeth within the same individual was highly correlated (R (2) = 0.78, P < 0.001). The tooth displacement decreased with age; however, this finding did not reach statistical significance (β = -0.11, 95% CI: -0.28, 0.05, P = 0.172). The tooth movement was higher in the maxilla than in the mandible (β = 0.47, 95% CI: 0.81, 0.86, P = 0.018).

CONCLUSION

Wide range of tooth displacement revealed slow and fast movers in this sample. Larger displacements were recorded in the maxilla compared to the mandible and in younger individuals.

Mechanisms of Bone Resorption in Periodontitis

Alveolar bone loss is a hallmark of periodontitis progression and its prevention is a key clinical challenge in periodontal disease treatment. Bone destruction is mediated by the host immune and inflammatory response to the microbial challenge. However, the mechanisms by which the local immune response against periodontopathic bacteria disturbs the homeostatic balance of bone formation and resorption in favour of bone loss remain to be established. The osteoclast, the principal bone resorptive cell, differentiates from monocyte/macrophage precursors under the regulation of the critical cytokines macrophage colony-stimulating factor, RANK ligand, and osteoprotegerin. TNF-α, IL-1, and PGE₂ also promote osteoclast activity, particularly in states of inflammatory osteolysis such as those found in periodontitis. The pathogenic processes of destructive inflammatory periodontal diseases are instigated by subgingival plaque microflora and factors such as lipopolysaccharides derived from specific pathogens. These are propagated by host inflammatory and immune cell influences, and the activation of T and B cells initiates the adaptive immune response via regulation of the Th1-Th2-Th17 regulatory axis. In summary, Th1-type T lymphocytes, B cell macrophages, and neutrophils promote bone loss through upregulated production of proinflammatory mediators and activation of the RANK-L expression pathways.

Correlation of the interleukin-29 levels in crevicular fluid and plasma with the genetic polymorphism in chronic and aggressive periodontitis patients

OBJECTIVE

To assess the effect of single nucleotide polymorphism (SNP) on the Interleukin (IL-29) quantity in gingival crevicular fluid (GCF) and plasma of chronic and aggressive periodontitis patients.

DESIGN

Patients with periodontal health (n=30), chronic generalized periodontitis (n=30) and generalized aggressive periodontitis (n=30) were subjected to IL-29 quantity estimation in GCF and plasma using enzyme linked immunosorbent assay and was correlated with IL-29 SNP (rs30461) using polymerase chain reaction.

RESULTS

IL-29 concentration in GCF and plasma was highest in aggressive periodontitis patients (114.17 ± 95.07pg/ml and 149.69 ± 109.90pg/ml respectively). The least concentration was found in subjects with healthy periodontium (47.50 ± 37.75pg/ml and 54.52 ± 37.53pg/ml) and in chronic periodontitis it was found to be 65.01 ± 41.26pg/ml and 81.17 ± 46.23pg/ml. The difference in the quantity of IL-29 in GCF and plasma among different groups was statistically significant (p<0.001 and p<0.001 respectively). rs30461 polymorphism of IL-29 analysis revealed that difference in the prevalence of A/A, A/G and G/G genotype among three groups was not statistically significant (p=0.097).

CONCLUSION

Increased quantity of IL-29 in GCF and plasma of subjects with periodontitis suggests a role in pathogenesis of periodontitis and the SNP (rs30461) is not related to susceptibility to periodontitis in this population of Indian individuals.

Cytokine production by leukocytes in patients with periodontitis

In the present study, we investigated the relation between clinical parameters and levels of interleukin (IL) -4 and -5, and tumour necrosis factor-α (TNF-α) in the leukocyte incubation medium (LIM) obtained from 26 patients with chronic periodontitis (P) and 26 control group subjects (C). The levels of cytokines IL-4 and IL -5 produced by the LIM stimulated with non-opsonised E. coli were determined using the Enzyme-Linked Immunosorbent Assay (ELISA) method and the levels of TNF-α were evaluated by applying Enzyme Amplified Sensitivity Immunoassay (EASIA). TNF-α levels in stimulated LIM were strongly positively correlated with clinical parameters such as the pocket probing depths (PPD), the clinical attachment level (CAL), the bleeding on probing (BOP) and oral hygiene index (OHI), whereas the IL-4 and IL-5 levels in the analogous medium were strongly negatively correlated with the clinical parameters. IL-4 and IL-5 levels in stimulated LIM of P group patients were significantly lower, whereas TNF-α levels were significantly higher than that in analogous medium of C group subjects. These differences were associated with the severity of periodontal disease.

Association between moderate to severe psoriasis and periodontitis in a Scandinavian population

Background

The aim of the present study was to compare the prevalence of periodontitis and alveolar bone loss among individuals with psoriasis and a group of randomly selected controls.

Methods

Fifty individuals with psoriasis and 121 controls completed a structured questionnaire, and were examined clinically and radiographically. Oral examination included numbers of missing teeth, probing pocket depth (PPD), clinical attachment level (CAL), presence of dental plaque and bleeding on probing, as well as alveolar bone loss from radiographs. Questionnaires requested information on age, gender, education, dental care, smoking habits, general diseases and medicament use. For adjustment for baseline differences between psoriasis individuals and controls the propensity score based on gender, age and education was computed using multivariate logistic regression. A subsample analysis for propensity score matched psoriasis individuals (n = 50) and controls (n = 50) was performed.

Results

When compared with controls, psoriasis individuals had significantly more missing teeth and more sites with plaque and bleeding on probing. The prevalence of moderate and severe periodontitis was significantly higher among psoriasis individuals (24%) compared to healthy controls (10%). Similarly, 36% of psoriasis cases had one or more sites with radiographic bone loss ≥3 mm, compared to 13% of controls. Logistic regression analysis showed that the association between moderate/severe periodontitis and psoriasis remained statistically significant when adjusted for propensity score, but was attenuated when smoking was entered into the model. The association between psoriasis and one or more sites with bone loss ≥3 mm remained statistically significant when adjusted for propensity score and smoking and regularity of dental visits. In the propensity score (age, gender and education) matched sample (n = 100) psoriasis remained significantly associated with moderate/severe periodontitis and radiographic bone loss.

Conclusions

Within the limits of the present study, periodontitis and radiographic bone loss is more common among patients with moderate/severe psoriasis compared with the general population. This association remained significant after controlling for confounders.

Cytological analysis of the periodontal pocket in patients with aggressive periodontitis and chronic periodontitis

BACKGROUND

Oral exfoliative cytology includes the study and interpretation of the features cells exfoliated from the oral mucosa. The aim of this study was to analyze cytological changes in the periodontal pocket of patients with different clinical stages of aggressive periodontitis (AP) and chronic periodontitis (CP).

MATERIALS AND METHODS

Patients aged 24-54 years, of whom 41 were diagnosed with AP, 40 with CP, sub-classified as mild, moderate and severe periodontitis, and 40 healthy individuals who were the control group. Samples of the epithelium of the periodontal pocket were taken for the cytological study.

RESULTS

Superficial and intermediate cell values were significantly greater in patients with AP than in patients with CP or the control group. Histiocyte number was higher in patients with CP than in those with AP, and differed significantly in both types of periodontitis compared to the control group. There were significant differences in polymorphonuclear neutrophil leukocytes when both types of periodontitis were compared to the control group. Microbial flora was statistically higher in patients with CP, and there were differences between patients with periodontitis and the control group.

CONCLUSIONS

The cytological study demonstrated that patients with AP had greater tissue damage, shown by the increase in intermediate and superficial cells of the epithelium of the periodontal pocket compared to the group of healthy subjects and to a lesser extent, to patients with CP. Only superficial cells made it possible to differentiate the sub-stages of the disease.

Origin of galactose-deficient immunoglobulin g in gingival crevicular fluid in periodontitis

BACKGROUND

Periodontitis is a chronic inflammatory disease initiated by a synergistic and dysbiotic microbial community that elicits a gingival inflammatory response leading to tissue breakdown. Periodontitis shares many characteristics with other chronic inflammatory diseases, including abnormal glycosylation of immunoglobulin (Ig)G. The current authors have previously demonstrated that IgG from gingival crevicular fluid (GCF) of patients with chronic periodontitis contains galactose (Gal)-deficient IgG.

METHODS

The origin of the aberrantly glycosylated IgG was determined by measuring levels of Gal-deficient IgG in GCF and serum from patients with periodontitis and non-periodontitis controls using lectin enzyme-linked immunosorbent assay. The Ig-producing cells and the proportion of cells producing Gal-deficient IgG were immunohistochemically determined in gingival tissues from patients with periodontitis by fluorescence microscopy. The results were statistically evaluated and correlated with clinical data.

RESULTS

The results indicate that GCF of patients with periodontitis had higher levels of Gal-deficient IgG compared with controls (P = 0.002). In gingival tissues, IgG was the dominant isotype among Ig-producing cells, and 60% of IgG-positive cells produced Gal-deficient IgG. Moreover, the proportion of Gal-deficient IgG-producing cells directly correlated with clinical parameters of probing depth and clinical attachment loss (AL).

CONCLUSION

These results suggest that the presence of Gal-deficient IgG is associated with gingival inflammation and may play a role in the worsening of clinical parameters of periodontitis, such as AL.

B cells promote obesity-associated periodontitis and oral pathogen-associated inflammation

Individuals with T2D and PD suffer significantly from the ability of one disease to intensify the other. Disease-associated inflammation is one mechanism thought to fuel this pathogenic feed-forward loop. Several lines of evidence indicate that proinflammatory B cells promote T2D and PD; thus, B cells are top candidates for a cell type that predisposes PD in T2D. To test directly the role of B cells in T2D-associated PD, we compared outcomes from oral Porphyromonas gingivalis challenge of lean WT or B cell-null mice with outcomes from mice that were obese and insulin-resistant before challenge. Obese WT mice responded to oral P. gingivalis challenge with significant periodontal bone loss, whereas obese B cell-null mice were protected completely from PD. By contrast, lean WT and B cell-null mice suffer similar periodontal bone loss in response to oral pathogen. B cells from obese/insulin-resistant hosts also support oral osteoclastogenesis and both oral and systemic production of inflammatory cytokines, including pro-osteoclastogenic TNF-α and MIP-2, an ortholog of human IL-8. B cells furthermore impact AT inflammation in obese, P. gingivalis-infected hosts. Taken together, these data show that fundamentally different mechanisms regulate PD in lean and obese hosts, with B cells able to promote PD only if the hosts are "primed" by obesity. These results justify more intense analysis of obesity-associated changes in B cells that predispose PD in human T2D.

Non-invasive in vivo imaging by confocal laser scanning microscopy of gingival tissues following natural plaque deposition

AIM

Imaging with Confocal Laser Scanning Microscopy (CLSM) generates high-resolution images and may be well suited for basic research in Periodontology and Implant Dentistry. The present study was aimed to explore the in vivo application of CLSM in experimentally induced gingivitis.

MATERIALS AND METHODS

Ten subjects were recruited and were advised to stop any oral hygiene of the upper front teeth for 7 days. The gingival tissues were observed using a Heidelberg Retina Tomograph combined with a Rostock Cornea Module at baseline and day 7. The system used a laser of 670 nm and the contrast was given by backscattering from different tissues. Each examination created 800-1200 images that were descriptively analysed.

RESULTS

After 7 days of abandoned oral hygiene, plaque scores and bleeding frequencies increased. By using CLSM images tooth hard substances, cells and plaque deposits were distinguishable. Increased epithelial cell irregularities, the apical migration of the sulcular epithelium, cellular infiltrates within the sulcus and plaque deposits were observed at day 7.

CONCLUSIONS

The present study showed for the first time that CLSM is suitable for in vivo imaging of the gingival sulcus and adjacent tissues.

Comparative analysis of gingival tissue antigen presentation pathways in ageing and periodontitis

AIM

Gingival tissues of periodontitis lesions contribute to local elevations in mediators, including both specific T cell and antibody immune responses to oral bacterial antigens. Thus, antigen processing and presentation activities must exist in these tissues to link antigen-presenting cells with adaptive immunity. We hypothesized that alterations in the transcriptome of antigen processing and presentation genes occur in ageing gingival tissues and that periodontitis enhances these differences reflecting tissues less capable of immune resistance to oral pathogens.

MATERIALS AND METHODS

Rhesus monkeys (n = 34) from 3 to 23 years of age were examined. A buccal gingival sample from healthy or periodontitis sites was obtained, total RNA isolated, and microarray analysis was used to describe the transcriptome.

RESULTS

The results demonstrated increased transcription of genes related to the MHC class II and negative regulation of NK cells with ageing in healthy gingival tissues. In contrast, both adult and ageing periodontitis tissues showed decreased transcription of genes for MHC class II antigens, coincident with up-regulation of MHC class I-associated genes.

CONCLUSION

These transcriptional changes suggest a response of healthy ageing tissues through the class II pathway (i.e. endocytosed antigens) and altered responses in periodontitis that could reflect host-associated self-antigens or targeting cytosolic intracellular microbial pathogens.