Periodontal disease at the biofilm-gingival interface

Utility of gingival crevicular fluid components for periodontal diagnosis

Periodontal diseases are highly prevalent chronic diseases, and severe periodontitis creates functional and esthetic problems and decreases self-esteem for a large percentage of the older population worldwide. In many cases of periodontitis, there is no distinct tell-tale pain that motivates a patient to seek treatment, rather the signs become clinically detectable late, and typically when the disease has progressed to a problematic level for the life of the dentition. Early periodontal screening and diagnostics tools will provide early recognition of periodontal diseases and facilitate timely management of the disease to reduce tooth loss. To this goal, gingival crevicular fluid is easily sampled, can be repeatedly and non-invasively collected, and can be tested for potential biomarkers. Moreover, the site specificity of periodontal diseases enhances the usefulness of gingival crevicular fluid sampled from specific sites as a biofluid for diagnosis and longitudinal monitoring of periodontal diseases. The present review aimed to provide up-to-date information on potential diagnostic biomarkers with utility that can be assayed from gingival crevicular fluid samples, focusing on what is new and useful and providing only general historic background textually and in a tabulated format.

Advances in periodontal biomarkers

Due to technologic advancements, periodontology has witnessed a boost in biomarker research over the past three decades. Indeed, with the aid of omics, our understanding of the healthy periodontium, pathogenesis of periodontal diseases, and healing after periodontal treatment has improved significantly. Yet, the traditional methods, periodontal probing and radiographies, remain the most common methods to diagnose periodontal disease and monitor treatment. Although these approaches can produce reliable diagnostic outcomes, they generally detect disease only after significant tissue degradation thus making treatment outcome highly uncertain. Accordingly, laboratories worldwide have collaborated with clinicians to design accurate, rapid and cost-effective biomarkers for periodontal disease diagnosis. Despite these efforts, biomarkers that can be widely used in early disease diagnosis and for treatment outcome prediction are far from daily use. The aim of this chapter is to give a general overview on periodontal health and diseases, and review recent advancements in periodontal biomarker research. A second aim will discuss the strengths and limitations of translating periodontal biomarker research to clinical practice. Genetic biomarkers of periodontitis are not discussed as the available confirmatory data is scarce.

Comparison of dental plaque flora between intellectually disabled patients and healthy individuals: a cross-sectional study

Periodontal diseases, including gingivitis, are highly prevalent in individuals with intellectual disability (ID). In particular, gingivitis can be difficult to cure owing to the lack of patient cooperation. Here, we evaluated differences in the oral bacterial flora between individuals with ID (n = 16) and healthy controls (n = 14) to facilitate the development of strategies for the prevention of periodontal disease in people with ID. Our results showed no significant difference in the number of decayed, missing, and filled teeth between the two groups. However, there were significant differences in the median papillary-marginal-attached index, plaque index, and gingival index between groups (P < 0.0001). Additionally, the mean probing depth in the ID group was significantly higher than that in the control group (P < 0.0001). The diversity of oral flora in people with ID and concurrent gingivitis was significantly lower than that of healthy individuals without periodontal disease. The relative abundances of Tannerella spp. and Treponema spp. were significantly higher in the ID group than in the control group at the genus level (P = 0.0383 and 0.0432, respectively), whereas that of Porphyromonas spp. was significantly lower in the ID group (P < 0.0001). Overall, our findings provided important insights into differences in the oral microbiota between patients with ID and healthy controls.

Mobile Point-of-Care Device Using Molecularly Imprinted Polymer-Based Chemosensors Targeting Interleukin-1β Biomarker

Molecularly imprinted polymers (MIPs) have garnered significant attention as a promising material for engineering specific biological receptors with superior chemical complementarity to target molecules. In this study, we present an electrochemical biosensing platform incorporating MIP films for the selective detection of the interleukin-1β (IL-1β) biomarker, particularly suitable for mobile point-of-care testing (POCT) applications. The IL-1β-imprinted biosensors were composed of poly(eriochrome black T (EBT)), including an interlayer of poly(3,4-ethylene dioxythiophene) and a 4-aminothiophenol monolayer, which were electrochemically polymerized simultaneously with template proteins (i.e., IL-1β) on custom flexible screen-printed carbon electrodes (SPCEs). The architecture of the MIP films was designed to enhance the sensor sensitivity and signal stability. This approach involved a straightforward sequential-electropolymerization process and extraction for leaving behind cavities (i.e., rebinding sites), resulting in the efficient production of MIP-based biosensors capable of molecular recognition for selective IL-1β detection. The electrochemical behaviors were comprehensively investigated using cyclic voltammograms and electrochemical impedance spectroscopy responses to assess the imprinting effect on the MIP films formed on the SPCEs. In line with the current trend in in vitro diagnostic medical devices, our simple and effective MIP-based analytical system integrated with mobile POCT devices offers a promising route to the rapid detection of biomarkers, with particular potential for periodontitis screening.

Metabolomics analysis in saliva from periodontally healthy, gingivitis and periodontitis patients

OBJECTIVE

The aim of this study was to investigate metabolomics markers in the saliva of patients with periodontal health, gingivitis and periodontitis.

BACKGROUND

The use of metabolomics for diagnosing and monitoring periodontitis is promising. Although several metabolites have been reported to be altered by inflammation, few studies have examined metabolomics in saliva collected from patients with different periodontal phenotypes.

METHODS

Saliva samples collected from a total of 63 patients were analysed by nuclear magnetic resonance (NMR) followed by ELISA for interleukin (IL)-1β. The patient sample, well-characterised clinically, included periodontal health (n = 8), gingivitis (n = 19) and periodontitis (n = 36) cases, all non-smokers and not diabetic.

RESULTS

Periodontal diagnosis (healthy/gingivitis/periodontitis) was not associated with any salivary metabolites in this exploratory study. Periodontal staging showed nominal associations with acetoin (p = .030) and citrulline (p = .047). Among other investigated variables, the use of systemic antibiotics in the previous 3 months was associated with higher values of the amino acids taurine, glycine and ornithine (p = .002, p = .05 and p = .005, respectively, at linear regression adjusted for age, gender, ethnicity, body mass index and staging).

CONCLUSION

While periodontal staging was marginally associated with some salivary metabolites, other factors such as systemic antibiotic use may have a much more profound effect on the microbial metabolites in saliva. Metabolomics in periodontal disease is still an underresearched area that requires further observational studies on large cohorts of patients, aiming to obtain data to be used for clinical translation.

Ageing and Inflammation: What Happens in Periodontium?

Periodontitis is a chronic inflammatory disease with a high incidence and severity in the elderly population, making it a significant public health concern. Ageing is a primary risk factor for the development of periodontitis, exacerbating alveolar bone loss and leading to tooth loss in the geriatric population. Despite extensive research, the precise molecular mechanisms underlying the relationship between ageing and periodontitis remain elusive. Understanding the intricate mechanisms that connect ageing and inflammation may help reveal new therapeutic targets and provide valuable options to tackle the challenges encountered by the rapidly expanding global ageing population. In this review, we highlight the latest scientific breakthroughs in the pathways by which inflammaging mediates the decline in periodontal function and triggers the onset of periodontitis. We also provide a comprehensive overview of the latest findings and discuss potential avenues for future research in this critical area of investigation.

Antibodies to oral pathobionts and colon cancer risk in the CLUE I cohort study

Periodontitis has been associated with an increased risk for gastrointestinal cancers. The objective of our study was to investigate the association of antibodies to oral bacteria and the risk of colon cancer in a cohort setting. Using the CLUE I cohort, a prospective cohort initiated in 1974 in Washington County, Maryland, we conducted a nested case-control study to examine the association of levels of IgG antibodies to 11 oral bacterial species (13 total strains) with risk of colon cancer diagnosed a median of 16 years later (range: 1-26 years). Antibody response was measured using checkerboard immunoblotting assays. We included 200 colon cancer cases and 200 controls matched on age, sex, cigarette smoking status, time of blood draw and pipe or cigar smoking status. Controls were selected using incidence density sampling. Conditional logistic regression models were used to assess the association between antibody levels and colon cancer risk. In the overall analysis, we observed significant inverse associations for 6 of the 13 antibodies measured (P-trends <.05) and one positive association for antibody levels to Aggregatibacter actinomycetemcomitans (ATCC 29523; P-trend = .04). While we cannot rule out a role for periodontal disease in colon cancer risk, findings from our study suggest that a strong adaptive immune response may be associated with a lower risk of colon cancer. More studies will need to examine whether the positive associations we observed with antibodies to A. actinomycetemcomitans reflect a true causal association for this bacterium.

Nuclear aberrations in the gingival epithelium of patients with chronic periodontitis

Context

Periodontitis characterized by mild symptoms in the early stages, which makes diagnostics problematic. The gingival epithelium can be used for micronucleus assay since gums are the area affected by the disease.

Aims

The aim of the study was to study the frequency of occurrence and the range of nuclear anomalies in gingival epithelium of healthy people and people with periodontitis.

Settings and Design

Scrapings of the gingival epithelium were made next to the central incisors (1.1) and molar teeth (1.7) in control and experimental groups (ten healthy males 35-50 years old and 10 males with periodontitis).

Materials and Methods

The preparations were stained by Romanowsky-Giemsa. The frequency of nuclear aberrations (‰), the accumulation index, and the repair index were determined.

Statistical Analysis Used

The differences in the medians of nuclear aberrations were determined using Wilcoxon and the Van-der-Waerden tests. The pathology proportions were compared using the Z-test. To determine the predictors of periodontitis, receiver operator characteristic analysis was used. For multiple comparisons, the Bonferroni correction was used.

Results

In the experimental group, the range of nuclear aberrations was wider, the ratio of karyolysis in the unaffected area was higher, than that in control; perinuclear vacuoles were fewer and macronuclei were more in the affected area. The frequency of cells with micronuclei over 1.33‰ in the affected area is the periodontitis marker.

Conclusions

Gingival epithelium can be used in micronucleus assay. Micronucleus test revealed a wider range of nuclear aberrations in the cells of the gingival epithelium and a higher frequency of occurrence of micronuclei in patients with periodontal disease compared to healthy subjects. Therefore, cytological signs of the inflammation appear earlier than the clinical ones and are verified more clearly. The markers of apoptosis and destruction of nuclei, and low repair index indicate normal elimination of damaged cells. An increased accumulation index in people with periodontitis may indicate the risk of malignant tumors.

The role of vitamin D in periodontal health and disease

Vitamin D plays an essential role in calcium and bone metabolism, immune regulation and possesses profound anti-inflammatory effects. Evidence suggests that low serum vitamin D is associated with increased severity of periodontitis, a chronic inflammatory condition characterised by destruction of the supporting tissues surrounding the tooth, which has several shared risk factors with other chronic non-communicable diseases. The biological functions of vitamin D are mediated by its strong anti-microbial, anti-inflammatory, and host modulatory properties. Experimental periodontitis models involving targeted deletion of 1α-hydroxylase, the enzyme responsible for the conversion of inactive substrate to active 1,25(OH)₂ D₃ (calcitriol), showed augmented alveolar bone loss and gingival inflammation. Vitamin D receptor (VDR) gene polymorphisms have also been associated with increased severity of periodontitis. Thus, the involvement of vitamin D in the pathogenesis of periodontitis is biological plausible. Clinical studies have consistently demonstrated an inverse relationship between serum 25OHD₃ and periodontal disease inflammation. However, due to the paucity of well-designed longitudinal studies, there is less support for the impact of vitamin D status on periodontal disease progression and tooth loss. The evidence emphasises the importance of maintaining vitamin D sufficiency in supporting periodontal health. This review aims to first examine the biological mechanisms by which vitamin D might influence the pathogenesis of periodontal disease and second, discuss the clinical evidence which implicate the role of vitamin D in periodontal disease.

Human gingival epithelial cells stimulate proliferation, migration, and tube formation of lymphatic endothelial cells in vitro

OBJECTIVE

The aim of this study was to investigate the response of gingival epithelial cells to microbial and inflammatory signals.

BACKGROUND

The gingival epithelial barrier provides the first line of defense and supports tissue homeostasis by maintaining the cross-talk between gingival epithelium, oral microbiota, and immune cells. Lymphatic vessels are essential to sustaining this homeostasis. The gingival epithelial cells have been shown to produce prolymphangiogenic factors during physiologic conditions, but their role in response to microbial and inflammatory signals is unknown.

METHODS

Immortalized human gingival epithelial cells (HGEC) and human dermal lymphatic microvascular endothelial cells (LEC) were cultured. HGEC were exposed to Porphyromonas gingivalis derived-LPS, human IL-1 beta/IL-1F2 protein, or recombinant human IL-6/IL-6R. Levels of vascular growth factors (VEGF-A, VEGF-C, and VEGF-D) in cell supernatants were determined by ELISA. LEC were grown to confluence, and a scratch was induced in the monolayer. Uncovered area was measured up to 48 h after exposure to conditioned medium (CM) from HGEC. Tube formation assays were performed with LEC cocultured with labelled HGEC or exposed to CM.

RESULTS

VEGF-A, VEGF-C, and low levels of VEGF-D were constitutively expressed by HGEC. The expression of VEGF-C and VEGF-D, but not VEGF-A, was upregulated in response to proinflammatory mediators. VEGF-C was upregulated in response to P. gingivalis LPS, but not to Escherichia coli LPS. A scratch migration assay showed that LEC migration was significantly increased by CM from HGEC. Both the CM and coculture with HGEC induced significant tube formation of LEC.

CONCLUSIONS

HGEC can regulate production of lymphangiogenic/angiogenic factors during inflammatory insults and can stimulate proliferation, migration, and tube formation of LEC in vitro in a paracrine manner.

What Has Immunology Brought to Periodontal Disease in Recent Years?

Recent decades have shed a new light on the pathomechanism of periodontal inflammation. While classic periodontology concentrates on biofilm control, oral hygiene improvement, professional tooth cleaning and surgical correction of damaged periodontal tissues, new aspects of the destruction mechanisms are being raised. Among them, the greatest attention is paid to the influence of host response on the clinical manifestations of the disease. Numerous studies have proved that the shift from gingivitis to periodontitis is not a simple progress of the disease, but an event occurring only in susceptible individuals. Susceptibility may result from appearance of local factors facilitating biofilm accumulation and/or maturation, or from systemic features, among which over-reaction and prolonged agitation of non-specific component of inflammatory response is crucial. The present paper summarizes the association between periodontology and immunology and updates the knowledge accrued mostly in the recent years. After a brief explanation of advances in understanding of the disease aetiology, the most studied and potentially viable immunological markers of periodontal disease are presented. Possible new therapeutic strategies, exploiting knowledge about the nature of host response—immunomodulation and reduction of chronic oxidative stress—are also presented.

Periodontitis promotes the expression of gingival transmembrane serine protease 2 (TMPRSS2), a priming protease for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Objectives

The oral cavity is one of the main entry sites for SARS-CoV-2. Gingival keratinocytes express transmembrane serine protease 2 (TMPRSS2), responsible for priming the SARS-CoV-2 spike protein. We investigated whether periodontitis increased the expression of TMPRSS2.

Methods

To investigate gene expression in periodontitis, we analyzed the expression of specific genes from (1) the Gene Expression Omnibus (GEO) dataset of 247 human gingival tissues and (2) an experimentally-induced periodontitis mouse model. Human gingival tissues with or without periodontitis were immunohistochemically stained using an anti-TMPRSS2 antibody. Analysis of the TMPRSS2 promoter was performed using a ChIP-Atlas dataset. TMPRSS2 expression was detected in cultured human keratinocytes using quantitative reverse transcription (qRT)-PCR and Western blot analysis.

Results

GEO dataset analysis and an experimentally-induced periodontitis model revealed increased expression of TMPRSS2 in periodontitis gingiva. The keratinocyte cell membrane in periodontitis gingiva was strongly immunohistochemically stained for TMPRSS2. Using ChIP-Atlas and GEO datasets, we screened for transcription factors that bind to the TMPRSS2 promoter region. We found one candidate, estrogen receptor 1 (ESR1), highly expressed in periodontitis gingiva. Analysis of the GEO dataset revealed a correlation between ESR1 and TMPRSS2 expression in gingival tissues. An ESR1 ligand induced TMPRSS2 expression in cultured keratinocytes.

Conclusions

Periodontitis increases TMPRSS2 expression in the cell membrane of gingival keratinocytes.

Molecular profiling of intrabony defects' gingival crevicular fluid

AIM

To profile, for the first time, the gingival crevicular fluid (GCF) of intrabony defects against a wide array of inflammatory and regenerative markers.

MATERIALS AND METHODS

Twenty-one patients contributed one intrabony defect and one periodontally healthy site. Clinical and radiographic measures were obtained. GCF samples were analyzed with multiplex bead immunoassays over 27 markers previously identified by our group. Comparisons were performed using Wilcoxon matched-pairs signed-ranks tests, using a Bonferroni corrected α = 0.05/27 = 0.0019.

RESULTS

Intrabony defect sites presented significantly increased GCF volume and disease-associated clinical and radiographic characteristics (p < .05). Intrabony defect sites presented significantly increased IL-1α, IL-1β, IL-6, IFN-γ, and MMP-8 levels compared with periodontally healthy sites (p < .0019). For regeneration markers, significantly higher FGF basic and VEGF levels were observed (p < .0019). Notably, traits of cell senescence were identified for the first time in the GCF.

CONCLUSIONS

The differentiation of intrabony defects from periodontally healthy control sites can be based on clinical and radiographic measures and on a differentiated GCF profile that is site-specific. Alongside catabolic processes, through significant up-regulation of inflammation and connective tissue remodeling, unique molecular characteristics of intrabony defects may render them a microenvironment amenable to regeneration. Traits of the senescence-associated secretory phenotype may suggest the existence of senescent cells during periodontal inflammation in intrabony defects.

Sulcus fluid volume, IL-6, and Il-1b concentrations in periodontal and peri-implant tissues comparing machined and laser-microtextured collar/abutment surfaces during 12 weeks of healing: A split-mouth RCT

OBJECTIVES

To compare gingival tissue healing at surgically manipulated periodontal sites and at sites receiving implants and healing abutments with machined (MS) vs laser-microtextured (LMS) surface placed with one-stage protocol.

MATERIAL AND METHODS

Twenty-four non-smoking patients each received two implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one implant with a MS collar and one immediate healing abutment with a MS, and one implant with a LMS collar and one immediate healing abutment with a LMS were used. Soft tissues healing at surgically manipulated periodontal tissues (T+) and at non-surgically manipulated periodontal tissues (T-) at MS implant sites and at LMS implant sites were compared by means of clinical and biochemical parameters at baseline and at 1-2-3-4-6-8 and 12 weeks.

RESULTS

PD and BoP mean values were statistically higher in MS than LMS implant sites (p<0.05). During early healing phase (1-4 weeks), MS and LMS peri-implant tissues and periodontal tissues at T(+) showed no statistically significant difference in crevicular fluid volume changes (p>0.05). Between 6 and 12 weeks, compared with T(+), no statistically significant difference in crevicular fluid volume and IL-6 and IL-1β concentrations was noted in LMS implant sites (p>0.05), while statistically significantly higher mean values were noted in MS implant sites (p<0.05).

CONCLUSIONS

Compared with T(+) and T(-), both MS and LMS implant sites presented a higher pro-inflammatory state in the early phase after surgery (1-4 weeks). At 12 weeks, only MS implant sites kept a higher pro-inflammatory state, while at LMS implant sites, it becomes similar to T(+) and T(-).

The relationship between periodontal disease and cognitive impairment in older adults of Korea

AIMS

A potential association between the periodontal disease and cognitive impairment has been suggested, but the results are not yet conclusive. This study investigated the association between the two diseases.

METHODS AND RESULTS

This study included 140 individuals (M: 48, F: 92, average age: 77.2). For assessing cognitive ability, MMSE-KC was used. The BGI index categorizes the periodontal disease based on important clinical parameters. In model 1 using the BGI index and the number of residual teeth as independent variables, the cognitive function status was significantly lower in the DL/MB group (β = -0.294), DL/LB group (β = -0.237). In Model 2 including systemic disease was the DL/MB group (β = -0.316) and in Model 3 which also added demographic characteristics, the DL/MB group (β = -0.229) was identified as a related factor (p < .05).

CONCLUSION

It can be concluded that periodontal disease is strongly associated with cognitive ability.

Impact of interproximal composite restorations on periodontal tissue health: Clinical and cytokine profiles from a pre-post quasi-experimental study

BACKGROUND

The aim of this study is to clinically and molecularly evaluate the effect of an interproximal iuxta/subgingival direct composite restoration on periodontal tissue healing.

METHODS

Individuals in need of a posterior iuxta/subgingival interproximal restoration were consecutively enrolled. After enrollment, a test (site with tooth decay) and a control site (intact contralateral tooth) were identified. After a periodontal examination (probing depth [PD], clinical attachment level, recession, plaque, and bleeding on probing [BOP]) and a sampling of gingival crevicular fluid, the composite restoration was performed (T₀ ). Clinical and molecular assessments were repeated at 3 (T₃ ), 6 (T₆ ), and 12 (T₁₂ ) months after the restoration. Intragroup pre-post comparisons for quantitative variables were performed either through one-way ANOVA or Kruskal-Wallis test. A multivariate linear regression analysis was then modeled. With α = 0.05, a power of 80% will be reached with the inclusion of 41 individuals.

RESULTS

Biometric parameters demonstrated an increased mean PD (ΔPDT₀ -T₁₂ = -0.83 mm; P = 0.001) and loss of attachment (AL) (ΔCALT₀ -T₁₂ = -0.91 mm; P = 0.005) in the test site at 12 months. Accordingly, in the final multivariate regression model the radiographic distance between the bone crest and the restorative margin at baseline accounted for the dependent variable "attachment loss (AL)" (ΔCALT₀ -T₁₂ ) (P <0.05).

CONCLUSIONS

Iuxta/subgingival interproximal restorative margins jeopardized clinically and molecularly the periodontal tissue healing at least up to 1 year of follow-up.

Compositional Data Analysis of Periodontal Disease Microbial Communities

Periodontal disease (PD) is a chronic, progressive polymicrobial disease that induces a strong host immune response. Culture-independent methods, such as next-generation sequencing (NGS) of bacteria 16S amplicon and shotgun metagenomic libraries, have greatly expanded our understanding of PD biodiversity, identified novel PD microbial associations, and shown that PD biodiversity increases with pocket depth. NGS studies have also found PD communities to be highly host-specific in terms of both biodiversity and the response of microbial communities to periodontal treatment. As with most microbiome work, the majority of PD microbiome studies use standard data normalization procedures that do not account for the compositional nature of NGS microbiome data. Here, we apply recently developed compositional data analysis (CoDA) approaches and software tools to reanalyze multiomics (16S, metagenomics, and metabolomics) data generated from previously published periodontal disease studies. CoDA methods, such as centered log-ratio (clr) transformation, compensate for the compositional nature of these data, which can not only remove spurious correlations but also allows for the identification of novel associations between microbial features and disease conditions. We validated many of the studies’ original findings, but also identified new features associated with periodontal disease, including the genera Schwartzia and Aerococcus and the cytokine C-reactive protein (CRP). Furthermore, our network analysis revealed a lower connectivity among taxa in deeper periodontal pockets, potentially indicative of a more “random” microbiome. Our findings illustrate the utility of CoDA techniques in multiomics compositional data analysis of the oral microbiome.

Biofilm inhibition in oral pathogens by nanodiamonds

Complex microbial communities, e.g., biofilms residing in our oral cavity, have recognized clinical significance, as they are typically the main cause for infections. Particularly, they show high resistance to conventional antibiotics, and alternatives including nanotechnology are being intensively explored nowadays to provide more efficient therapeutics. Diamond nanoparticles, namely, nanodiamonds (NDs) with many promising physico-chemical properties, have been demonstrated to work as an effective antibacterial agent against planktonic cells (free-floating state). However, little is known about the behaviors of NDs against biofilms (sessile state). In this study, we uncovered their role in inhibiting biofilm formation and their disrupting effect on preformed biofilms in several selected orally and systemically important organisms. The current findings will advance the mechanistic understanding of NDs on oral pathogens and might accelerate corresponding clinical translation.

An activated-zinc oral rinse reduces pro-inflammatory cytokine secretion and promotes proliferation in Porphyromonas gingivalis LPS-challenged gingival tissues - A pilot study

Objectives

The use of adjunct post‐treatment mouth rinses containing chlorhexidine (CHX) for periodontitis patients is associated with side effects that reduce patient compliance. Our aim was to evaluate the proinflammatory and cell proliferation effects of an activated‐zinc mouth rinse (SM) that has been suggested as an alternative post‐treatment therapeutic.

Materials and Methods

Tissue models of gingival epithelium were used to simulate periodontal disease and compare inflammatory reactions after treatment with CHX or SM. Tissues were exposed to Porphyromonas gingivalis LPS and wounded to simulate periodontal disease. Tissues were treated and incubated for 6, 12, or 24 h. Inflammatory cytokines were measured in culture medium by ELISA and local expression of Toll‐like receptor (TLR)‐4 and proliferation marker Ki‐67 was visualized by immunohistochemistry.

Results

SM and CHX treatments decreased secretion of IL‐1β and IL‐8 into culture media at all time points. IL‐1β secretion levels were further decreased by SM compared to CHX treatment at all time points. TLR‐4 expression appeared significantly increased 12 h post‐treatment in the CHX tissues but remained relatively low in SM tissues at all time points. Ki‐67 results suggest that cell proliferation was increased in the SM tissues earlier than CHX tissues.

Conclusions

Our data suggest that SM may reduce inflammation in gingival tissues.

Porphyromonas gingivalis, the most influential pathogen in red-complex bacteria: A cross-sectional study on the relationship between bacterial count and clinical periodontal status in Japan

BACKGROUND

Porphyromonas gingivalis is a key pathogen in microbiota associated with periodontitis. The purpose of the present study was to assess the association between salivary counts of red-complex bacteria and clinical periodontal status in a Japanese population.

METHODS

A total of 977 subjects who visited a general dental clinic in Japan from 2003 to 2006 were enrolled in the study. Stimulated saliva was obtained, and the amounts of major periodontal bacteria were measured using real-time polymerase chain reaction. Probing pocket depth (PPD), bleeding on probing (BOP), and each subject's average proximal bone crest level (BCL) on dental radiographs were measured.

RESULTS

The number of P. gingivalis strongly associated with percentage of 4 mm or more PPD sites, BOP positive percentage, and 1.5 mm or more BCL sites. The detection of P. gingivalis with Treponema denticola and/or Tannerella forsythia showed a high rate of three positive clinical parameters, whereas the only P. gingivalis detected group and those without P. gingivalis had a low rate of three positive clinical parameters.

CONCLUSION

Among red-complex bacteria, the amount of P. gingivalis showed the strongest association with the severity of periodontal condition, and co-occurrence of P. gingivalis with T. denticola and/or T. forsythia showed heightened progression of periodontitis.

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.

Efficacy of Psidium guajava and Allium sativum Extracts as Antimicrobial Agents against Periodontal Pathogens

Background:

The accumulation and maturation of bacterial plaque at the gingival margin is widely recognized as the primary etiological factor in the development of chronic periodontitis. With the rise in bacterial resistance to antibiotics, there is considerable interest in the development of other classes of antimicrobials for the control of infection.

Aim:

The aim of this study was to evaluate the efficacy of Psidium guajava (guava) and Allium sativum (garlic) on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.

Materials and Methods:

Aqueous guava extract (AGvE), ethanolic guava extract (EGvE), aqueous garlic extract (AGE), and ethanolic garlic extract (EGE) were prepared. The inhibitory effects of these extracts for the periodontal pathogens were tested by agar well diffusion method. Minimal inhibitory concentration (MIC) of the aqueous and ethanol extracts of guava and garlic was determined by macrobroth dilution method. Minimum bactericidal concentration (MBC) was done to observe the bactericidal effect of the guava and garlic extracts against the organisms.

Results:

Of the AGE, 25, 50, and 75 μL showed 16, 20, and 25 mm zone of inhibition, respectively, on P. gingivalis. The AGE showed greater bacteriostatic activity against the P. gingivalis with MIC determined at 16.6 μL/mL. MIC determined for AGvE and EGvE was at 75 μL/mL concentration for P. gingivalis, whereas EGvE showed the activity at 75 μL/mL on P. gingivalis. MIC determined for AGvE was at 50 μL/mL, whereas MIC determined for EGvE was at 3.12 μL/mL for A. actinomycetemcomitans.

Conclusion:

P. guajava and A. sativum displayed a significant antibacterial effect. A. sativum was found to be most effective against P. gingivalis, whereas P. guajava showed the highest efficacy on A. actinomycetemcomitans.

A review of T helper 17 cell-related cytokines in serum and saliva in periodontitis

Periodontitis is a chronic inflammatory disease with a complex underlying immunopathology. Cytokines, as molecular mediators of inflammation, play a role in all stages of disease progression. T helper 17 (Th17) cells are thought to play a role in periodontitis. Th17 cell development and maintenance requires a pro-inflammatory cytokine milieu, with many of the cytokines implicated in the pathogenesis of periodontitis. Serum and saliva are easily accessible biofluids which can represent the systemic and local environment to promote the development of Th17 cells. Here we review human clinical studies that investigate IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L and TNF-α in serum and saliva in periodontitis. We highlight their putative role in the pathogenesis of periodontitis and place them within a wider context of animal and other clinical studies.

Diagnostic Accuracy of Oral Fluids Biomarker Profile to Determine the Current and Future Status of Periodontal and Peri-Implant Diseases

Severe periodontitis is ranked as the sixth most prevalent disease affecting humankind, with an estimated 740 million people affected worldwide. The diagnosis of periodontal diseases mainly relies upon assessment of conventional clinical parameters. However, these parameters reflect past, rather than current, clinical status or future disease progression and, likely, outcome of periodontal treatment. Specific and sensitive biomarkers for periodontal diseases have been examined widely to address these issues and some biomarkers have been translated as point-of-care (PoC) tests. The aim of this review was to provide an update on PoC tests for use in the diagnosis and management of periodontal diseases. Among the PoC tests developed so far, active matrix metalloproteinase-8 has shown promising results in terms of diagnostic and prognostic values. However, further studies are required to increase the sensitivity and specificity via combining more than one biomarker and merging these test kits with periodontal risk assessment tools. Furthermore, the validity of these test kits needs to be investigated by applying the results in further independent studies and the impact on these test kits', together with the results of risk factors for periodontal diseases, such as diabetes and smoking, also needs to be examined.

Could Vitamin D influence risk for Periodontal Disease - to "D" or not to "D"?

PURPOSE OF REVIEW

The purpose of this review is to discuss the literature on associations between vitamin D and periodontal disease, including its strengths and weaknesses. Future direction for continued work in this area is provided.

RECENT FINDINGS

Research in cross-sectional cohorts, surveys, and case-control studies provide support for a role of vitamin D in periodontal disease, especially using clinical indicators such as bleeding on probing and clinical attachment loss. However, these studies have a number of limitations. They cannot establish temporality of these associations. Most case-control studies have been limited in sample size and have inconsistent findings. A number of cross-sectional studies are restricted to select populations (e.g., persons with HIV, diabetes, rheumatoid arthritis) limiting extrapolation of findings to the general aging population.Fewer prospective studies have been conducted, and only three have examined associations using a biomarker for vitamin D that reflects exposure from all its sources (sunlight, diet and supplements). One study is limited by using self-reported measures of disease outcomes, and only two used measures of alveolar crestal height. However, of the prospective studies published, there is a suggestion that vitamin D might prevent against tooth loss. Only two randomized controlled trials have examined these associations, and they support the effects of vitamin D supplementation on prevention of tooth loss and gingival bleeding.

SUMMARY

We strongly suggest that new research should focus on prospective study designs with followup of participants longer than a decade and long-term clinical trials. Such studies should incorporate measures of alveolar bone loss and tooth loss with indication for reason for tooth loss. Such clinical trials should be designed to examine both the influence of vitamin D supplementation alone as well as with other nutrients (e.g., calcium) or therapeutic medications (e.g., bisphosphonates). Currently, there is no strong evidence to suggest that vitamin D protects against development of periodontal disease.

Interleukin-1β is a potential therapeutic target for periodontitis: a narrative review

Interleukin(IL)-1β, a pro-inflammatory cytokine, was elevated and participates in periodontitis. Not only the link between IL-1β and periodontitis was proved by clinical evidence, but also the increased IL-1β triggers a series of inflammatory reactions and promotes bone resorption. Currently, IL-1β blockage has been therapeutic strategies for autoimmune and autoinflammatory diseases such as rheumatoid arthritis, cryopyrin-associated periodic syndromes, gout and type II diabetes mellitus. It is speculated that IL-1β be a potential therapeutic target for periodontitis. The review focuses on the production, mechanism, present treatments and future potential strategies for IL-1β in periodontitis.

Fretibacterium sp. human oral taxon 360 is a novel biomarker for periodontitis screening in the Japanese population

Background

Periodontitis is a common inflammatory disease, leading to bone destruction and tooth loss. Screening for periodontitis is important in preventing the progress of this disease. Various types of bacteria have been examined as potential screening targets, but only culturable pathogenic bacteria have been considered candidates. Recently, the various uncultivable bacteria have been identified in microbiome studies, but the value of these bacteria in periodontitis screening remains unknown.

Objectives

The aim of this study was to evaluate the diagnostic use of uncultivable bacteria Fretibacterium sp. HOT 360 and TM7 sp. HOT 356 for periodontitis screening in the Japanese population.

Material and methods

Stimulated saliva samples were collected from 217 participants (periodontitis group, n = 157; healthy group, n = 60). The two uncultivable bacterial species selected were: Fretibacterium sp. human oral taxon 360 (Fretibacterium sp. HOT 360) and TM7 sp. human oral taxon 356 (TM7 sp. HOT 356). The levels of these two bacterial species were compared with those of Porphyromonas gingivalis (P. gingivalis), a keystone pathogen in periodontitis. These three species of bacteria were then quantified using qualitative real-time polymerase chain reaction (qPCR) with specific primers and Taqman probes. Statistical analysis was performed by SPSS 20.0 software. P value was statistically significant at .05.

Results

The populations of uncultivable bacterial species TM7 sp. HOT 356 and Fretibacterium sp. HOT 360 were significantly higher in periodontitis group than in healthy group. Only Fretibacterium sp. HOT 360 showed a significantly positive correlation with such periodontal parameters as probing pocket depth (PPD) and bleeding on probing (BOP).

Conclusion

These findings indicate that uncultivable bacteria Fretibacterium sp. HOT 360 can be used as a saliva-based diagnostic bacterial biomarker for periodontitis screening.

Contemporary approaches for identifying individual risk for periodontitis

Key breakthroughs in our understanding of the etiology and principles of predictable treatment of patients with chronic periodontitis first emerged in the late 1960s and carried on into the mid-1980s. Unfortunately, some generalizations of the evidence led many to believe that periodontitis was a predictable result of exposure to bacterial plaque accumulations over time. For a brief period, the initial plaque concept was translated by some to implicate specific bacterial infections, with both concepts (plaque exposure and specific infection) being false assumptions that led to clinical outcomes which were frustrating to both the clinician and the patient. The primary misconceptions were that every individual was equally susceptible to periodontitis, that disease severity was a simple function of magnitude of bacterial exposure over time, and that all patients would respond predictably if treated based on the key principles of bacterial reduction and regular maintenance care. We now know that although bacteria are an essential initiating factor, the clinical severity of periodontitis is a complex multifactorial host response to the microbial challenge. The complexity comes from the permutations of different factors that may interact to alter a single individual's host response to challenge, inflammation resolution and repair, and overall outcome to therapy. Fortunately, although there are many permutations that may influence host response and repair, the pathophysiology of chronic periodontitis is generally limited to mild periodontitis with isolated moderate disease in most individuals. However, approximately 20%-25% of individuals will develop generalized severe periodontitis and probably require more intensive bacterial reduction and different approaches to host modulation of the inflammatory outcomes. This latter group may also have serious systemic implications of their periodontitis. The time appears to be appropriate to use what we know and currently understand to change our approach to clinical care. Our goal would be to increase our likelihood of identifying those patients who have a more biologically disruptive response combined with a more impactful microbial dysbiosis. Current evidence, albeit limited, indicates that for those individuals we should prevent and treat more intensively. This paper discusses what we know and how we might use that information to start individualizing risk and treat some of our patients in a more targeted manner. In my opinion, we are further along than many realize, but we have a great lack of prospective clinical evidence that must be accumulated while we continue to unravel the contributions of specific mechanisms.

A randomized, double-blind, placebo-controlled multicenter study for evaluating the effects of fixed-dose combinations of vitamin C, vitamin E, lysozyme, and carbazochrome on gingival inflammation in chronic periodontitis patients

Background

To evaluate gingival inflammation from fixed-dose combinations of vitamin C, vitamin E, lysozyme and carbazochrome (CELC) in the treatment of chronic periodontitis following scaling and root planing.

Methods

One hundred patients were randomly assigned to receive CELC (test) or placebo (control) for the first 4 weeks at a 1:1 ratio, and both groups received CELC for the remaining 4 weeks. Primary outcome was the mean change in the gingival index (GI) after 4 weeks. Secondary outcomes included mean change in GI after 8 weeks and plaque index, probing depth, clinical attachment level, and VAS at 4 weeks and 8 weeks.

Results

Ninety-three patients completed the study. The GI in the test group significantly decreased after 4 weeks (p < 0.001) and 8 weeks (p < 0.001). The mean change from baseline in GI significantly decreased in the test group compared to the control group after 4 weeks (p = 0.015). In the GEE model adjusting for age, gender and visits, the test group showed 2.5 times GI improvement compared to the control group (p = 0.022).

Conclusions

Within the study, CELC showed a significant reduction in gingival inflammation compared with a placebo. Other parameters, however, were similar between groups.

Trial registration

KCT0001366 (Clinical Research Information Service, Republic of Korea) and 29 Jan 2015, retrospectively registered.

Exploring a temporal relationship between biofilm microbiota and inflammatory mediators during resolution of naturally occurring gingivitis

BACKGROUND

This study uses multiple, contemporary methodologies to expand our knowledge of the temporal relationship between host-microbial interactions and clinical signs of gingivitis.

METHODS

Subgingival plaque and crevicular fluid samples were collected from 31 systemically healthy adults with naturally occurring plaque-induced gingivitis. Professional prophylaxis was administered and participants were followed over 7 weeks. Microbial characterization was performed using a bead-based hybridization assay and cytokine analysis using bead-based flow cytometry.

RESULTS

The provision of sequential interventions, oral hygiene instruction, and subsequent professional prophylaxis brought about significant reduction of plaque and resolution of gingivitis at all post baseline time points (P < 0.0001). Candidate cytokines that increased significantly (95% level) were interleukin (IL)-1β, matrix metalloproteinases (MMP)-1, MMP-3, MMP-8, MMP-9, from baseline to week 2; regulated on activation, normal T cell expressed and secreted (RANTES) at week 4 and week 8; macrophage inflammatory protein (MIP)-1α and MIP-1β at week 8. Resolution of inflammation was accompanied by a shift in the microbiological flora toward those species associated with health.

CONCLUSIONS

This study provides further evidence of the dynamic relationships that exist between the overt clinical signs, the microbial biofilm, and the host response in gingivitis and upon resolution following clinical interventions. Understanding the interactions between the host immune system and subgingival microbial communities during the resolution of established gingivitis continues to evolve as additional knowledge is achieved through using new analytical technologies. The present study confirms a critical effect of oral hygiene measures on restoration of microbial eubiosis in subgingival communities, confirming the important role for home care and professional intervention in maintaining oral health.

BAX Gene Overexpression in the Tongue Could Warn of Infection Risk due to Periodontal Pathogens

Background:

Different host proteins play a central role in cell response during bacterial infections, the Bcl-2-Associated X protein (BAX) and Vascular Cell Adhesion Protein 1 (VCAM-1) are often reported in infective primary events during cell injury.

Objective:

The aim of this study is to evaluate the predictive value of these two proteins as biomarkers of oral bacterial infection, with particular emphasis on the tongue, which plays an important role in microbial homeostasis in the mouth.

Methods:

Twenty-nine patients were recruited and divided according to the Periodontal Index (CPI), 4 of them were severely compromised periodontal patients. Oral hygiene, gingival tissues and plaque presence were evaluated clinically. The laboratory analysis carried out on tongue tissue included: total bacterial genomes, proportion of specific periopathogens and BAX -VCAM-1 expression rate, while Reactive Oxygen Species (ROS) were measured in saliva.

Results:

Neither tongue microbiological status nor salivary ROS level corresponded with the state of disease. VCAM-1 mRNA expression rate was comparable in all patients but, on the contrary, BAX expression resulted high in periodontally-compromised patients and appears related to periodontal status in the analyzed subjects.

Conclusion:

This preliminary work suggests that the BAX protein is a possible candidate in a prognostic marker study for oral diseases started by periodontal bacteria. For example, none of the evaluated clinical and microbiological parameters could predict the presence, prognosis or recurrence of periodontal diseases. This biomarker could be a valuable tool in determining the risk, diagnosis and prognosis of this human illness.

GWAS for Interleukin-1β levels in gingival crevicular fluid identifies IL37 variants in periodontal inflammation

There is no agnostic GWAS evidence for the genetic control of IL-1β expression in periodontal disease. Here we report a GWAS for "high" gingival crevicular fluid IL-1β expression among 4910 European-American adults and identify association signals in the IL37 locus. rs3811046 at this locus (p = 3.3 × 10-22) is associated with severe chronic periodontitis (OR = 1.50; 95% CI = 1.12-2.00), 10-year incident tooth loss (≥3 teeth: RR = 1.33; 95% CI = 1.09-1.62) and aggressive periodontitis (OR = 1.12; 95% CI = 1.01-1.26) in an independent sample of 4927 German/Dutch adults. The minor allele at rs3811046 is associated with increased expression of IL-1β in periodontal tissue. In RAW macrophages, PBMCs and transgenic mice, the IL37 variant increases expression of IL-1β and IL-6, inducing more severe periodontal disease, while IL-37 protein production is impaired and shows reduced cleavage by caspase-1. A second variant in the IL37 locus (rs2708943, p = 4.2 × 10-7) associates with attenuated IL37 mRNA expression. Overall, we demonstrate that IL37 variants modulate the inflammatory cascade in periodontal disease.

Qualitative, quantitative and genotypic evaluation of Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum isolated from individuals with different periodontal clinical conditions

Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum are strongly associated with periodontitis, and their evaluations are relevant to understand their role in the etiology and progression of periodontal diseases. In this study, the qualitative and quantitative detection of A. actinomycetemcomitans and F. nucleatum, as well as their genetic diversity, were evaluated in individuals with gingivitis, chronic periodontitis and periodontally healthy. In addition, the biotyping, serotyping, and prevalence of the ltx and cdt genes in A. actinomycetemcomitans were also determined. Subgingival biofilms obtained from gingivitis (70), periodontitis (75) and healthy (95) individuals were analyzed by cultures and PCR. Bacterial typing and presence of ltx and cdt genes in A. actinomycetemcomitans were also verified. DNA from A. actinomycetemcomitans and F. nucleatum was detected respectively, in 65.7% and 57.1% of gingivitis, 80% and 68% of periodontitis, and 57.8% and 37.8% of healthy. A. actinomycetemcomitans from gingivitis were biotypes I, II, IV, V, and X, and serotypes a, c, and e. In periodontitis, biotypes II, VI, and X, and serotypes a, b, and c were found. In healthy subjects, biotypes II and X, and serotypes b and c were found. The LTX and ltxA were observed in strains from gingivitis and periodontitis pockets. Subsequently, our data also showed no direct relationship between ltxA gene expression and leukotoxin gene 530-bp presence. On the other hand, cdt gene predominated during the inflammatory disease process. Our results strongly support a role of A. actinomycetemcomitans and F. nucleatum in advanced stage of periodontal disease.

In search of appropriate measures of periodontal status: The Periodontal Profile Phenotype (P3 ) system

BACKGROUND

This paper focuses on Periodontal Profile Class (PPC), a component of the Periodontal Profile Phenotype (P3 ) System that may be more representative of the periodontitis phenotype than current case definitions of periodontitis. Data illustrate the unique aspects of the PPC compared with other commonly used periodontal classification indices.

METHODS

Latent Class Analysis (LCA) identified discrete classes of individuals grouped by tooth-level clinical parameters. The analysis defined seven distinct periodontal profile classes (PPC A through G) and seven distinct tooth profile classes (TPC A through G). This LCA classification was an entirely data-derived agnostic process without any preconceived presumptions of what constituted disease.

RESULTS

Comparing the PPC with the Centers for Disease Control/American Academy of Periodontology (CDC/AAP) and European indices, the PPC is unique in that it contains four disease classes not traditionally used. Less than half of individuals classified as Healthy by both the CDC/AAP and European indices were Healthy using the PPC. About 25% of those classified as Severe by CDC/AAP and European indices were PPC-Severe. The remainder spread out over the High Gingival Index, Posterior Disease, Tooth Loss, and Severe Tooth Loss phenotypes.

CONCLUSIONS

The PPC classification provides a significant departure from the traditional clinical case status indices that have been used, but has resulted in clinical phenotypes that are quite familiar to most clinicians who take notice of the distribution of missing teeth, areas of recession, diminished periodontal support, and other aspects of the dentition while conducting a periodontal examination. The mutually exclusive categories provided by the PPC system provide periodontal clinical summaries that can be an important component of precision dentistry.

Hyposalivation and 10-year all-cause mortality in an elderly Japanese population

OBJECTIVE

To evaluate the association of salivary flow rate with all-cause mortality among older Japanese adults. We hypothesised that hyposalivation would be a marker for mortality.

BACKGROUND

Hyposalivation, which is an objectively measurable decrease in salivary flow, is highly prevalent among older adults. It is associated with malnutrition and poor general health.

METHODS

The study population comprised 600 community-dwelling Japanese adults (306 men and 294 women), who were 70 years old at baseline. They underwent stimulated salivary flow rate (SSFR) measurements and were followed up during a 10-year study period. After stratification by sex, the hazard ratios of all-cause mortality were estimated using Cox proportional hazards regression analysis comparing groups with and without hyposalivation (ie, SSFR < 0.7 mL/min).

RESULTS

The baseline prevalence of hyposalivation was 27.8% (85/306) among men and 47.3% (139/294) among women. During a mean (standard deviation) follow-up period of 104 (27) months, 80 deaths occurred: 60 (75.0%) deaths among men and 20 (25.0%) deaths among women. After adjusting for the number of remaining teeth, smoking status, exercise, hypoalbuminemia, diabetes and cardiovascular disease, hyposalivation at baseline was significantly associated with all-cause mortality among men (adjusted hazard ratio, 1.71; 95% confidence interval, 1.01-2.89). In contrast, no association between SSFR and all-cause mortality existed among women.

CONCLUSION

Hyposalivation could be a marker for all-cause mortality among older community-dwelling Japanese men. Future studies investigating the association between SSFR and cause-specific mortality are warranted.

Impact of periodontal intervention on local inflammation, periodontitis, and HIV outcomes

OBJECTIVE

The aim of this study was to determine active periodontal disease status in HIV and to determine the impact of periodontal disease resolution on HIV status.

METHODS

In this longitudinal cohort study, 73 HIV-positive subjects received comprehensive dental care. AAP, CDC/AAP, and BGI case definitions determined periodontal classification. Likelihood and frequency of moderate/severe periodontal disease were assessed based on demographic variables. The influence of periodontal intervention was assessed at baseline, 12, and 24 months. IL-6 was measured in a subset of subjects.

RESULTS

Of the periodontal classifications, BGI demonstrated the highest percentage category improvement with the intervention (>50%). Moderate/severe periodontitis was positively associated with HIV regardless of race, smoking status, gender, income level, and age, and was associated with increased IL-6. At baseline, the majority of subjects had severe periodontal disease regardless of ART status. Subjects with suppressed viral load at baseline demonstrated a significant improvement in BGI classification (P = 0.026), increased CD4 counts (P = 0.027), and decreased IL-6 levels (P = 0.03).

CONCLUSIONS

Periodontal inflammation was prevalent regardless of ART status. In virologically suppressed subjects, the intervention decreased periodontitis with a concomitant IL-6 decrease and CD4 increase. These findings suggest a relationship between periodontal inflammation, oral microbial translocation, and HIV status.

In Defense of Flossing: Part II-Can We Agree It's Premature to Claim Flossing Is Ineffective to Help Prevent Periodontal Diseases?

Periodontal diseases are complex, multifactorial disorders. Effective daily plaque control promotes gingival/periodontal health. Recent meta-analyses and other reviews have found inconclusive evidence to support that tooth flossing promotes gingival/periodontal health. Ideally, the claim should have been that, "at present, we do not have high-quality evidence from well-designed randomized clinical trials to determine whether flossing lowers the risk for periodontal diseases." Rather than "not proven to be effective," the lay public may now think that flossing is "almost entirely unhelpful and/or unnecessary." How does the dental community communicate the nuances of this topic? Herein, we examine the key structural issues underlying this area of research. We assert that effective flossing between specific teeth can promote gingival/periodontal health. Furthermore, we explore the nuances for whom this may be true and untrue, why our evidence is lacking, and what can be done to clarify the effectiveness of flossing on clinical outcomes.

Gingival crevicular fluid as a source of biomarkers for periodontitis

In evaluating the pathogenesis of periodontal diseases, the diagnostic potential of gingival crevicular fluid has been extensively explored during the last twenty years, from initially just confirming health and disease states to more recently investigating it as a potential prognostic tool. As host susceptibility is a critical determinant in periodontal disease pathogenesis, the inflammatory mediator levels present in gingival crevicular fluid represent relevant risk indicators for disease activity. Considerable work has been carried out to identify the many different cytokine inflammatory pathways and microbial stimuli that are associated with periodontal disease pathogenesis. Now, 'omics' approaches aim to summarize how these pathways interact and probably converge to create critical inflammatory networks. More recently, gingival crevicular fluid metabolomics appears promising as an additional diagnostic method. Biofilm structure and the host inflammatory response to the microbial challenge may induce specific inflammatory signatures. Host genetics and epigenetics may also modulate microbial colonization, adding to the multiplicity of potential causal pathways. Omics analyses of gingival crevicular fluid, measuring microbial and host interactions in association with the onset and progression of periodontal diseases, still show the potential to expand the landscape for the discovery of diagnostic, prognostic and therapeutic markers.

Common Polymorphisms in IFI16 and AIM2 Genes Are Associated With Periodontal Disease

BACKGROUND

The single nucleotide polymorphism (SNP) context of a previously identified periodontitis-associated locus is investigated, and its association with microbial, biologic, and periodontal disease clinical parameters is examined.

METHODS

A 200-kb spanning region of 1q12 previously highlighted in a genome-wide association scan among 4,766 European American individuals (SNP rs1633266) was annotated. Two haplotype blocks were selected. Association of these polymorphisms with data on microbial plaque composition, gingival crevicular fluid (GCF)-interleukin (IL)-1β levels, and clinical parameters of periodontal disease were examined. Descriptive analysis of IFI16 and AIM2 protein expression in gingival tissues from healthy individuals (n = 2) and individuals with chronic periodontitis (n = 2) was done via immunohistochemistry.

RESULTS

The highlighted locus is a 100-kb region containing the interferon γ-inducible protein 16 (IFI16) and absent in melanoma 2 (AIM2) genes. Two haplotype blocks, rs6940 and rs1057028, were significantly associated with increased extent bleeding on probing and levels of microorganisms Porphyromonas gingivalis, Tannerella forsythia, and Campylobacter rectus (P ≤0.05). Haplotype block rs1057028 was also significantly associated with pathogens Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans, increased GCF-IL-1β levels, and extent of probing depth ≥4 mm (P ≤0.05). Prevalence of severe periodontitis (biofilm-gingival interface P3 classification) was positively associated with haplotype block rs1057028. Similar trends were observed for haplotype block rs1057028. IFI16 and AIM2 protein expression was observed in multiple cell types of gingival tissues, including inflammatory cells.

CONCLUSION

This study found IFI16 and AIM2 SNPs associated with higher levels of periodontal microorganisms and an increased percentage of periodontal disease clinical parameters, suggesting the need for functional studies and additional fine-mapping of variants in the 1q12-locus.

Effect of Alox-15 Polymorphism on GCF Levels of Lipoxin-A4 in Chronic Periodontitis: A Preliminary Study

Lipoxins play an important role in periodontal resolution, hence, investigation of genetic polymorphism of lipoxin gene may provide important information on the role of lipoxins in periodontal disease pathogenesis. The aim of this study was to investigate a polymorphism of C-to-T substitution at position c.-292 in ALOX15 (reticulocyte-type 15 lipoxygenase 1) gene in patients with chronic periodontitis and to associate the polymorphism with gingival crevicular fluid (GCF) lipoxin A4 (LXA4) levels. Forty-five chronic periodontitis and 45 periodontally healthy patients were included in this case-control study. Plaque index, calculus index, sulcus bleeding index, full mouth probing depth (PD) and clinical attachment loss (CAL) were recorded. GCF and blood samples were collected. GCF was analyzed for LXA4 levels by enzyme linked immunosorbant assay. Genotyping of ALOX15 polymorphism was studied using PCR. Mean LXA4 was lower in periodontitis group compared to the periodontally healthy group. There was a negative correlation between CAL and LXA4. The CC genotype was higher in the study group than in the control group. In the study group, mean CAL was significantly lower among individuals with the CT genotype. Mean LXA4 was significantly lower in CC genotype (45.0±7.11 ng/mL) compared to CT genotype (50.81±5.81 ng/mL) among the patients with periodontitis. The results suggest that LXA4 and c.-292T allele are associated with periodontal health. Polymorphisms in the ALOX15 gene may influence periodontal disease pathogenesis. Hence, investigation of such polymorphisms could benefit the evaluation of lipoxins role in periodontal disease.

Genome-wide association study of biologically informed periodontal complex traits offers novel insights into the genetic basis of periodontal disease

Genome-wide association studies (GWAS) of chronic periodontitis (CP) defined by clinical criteria alone have had modest success to-date. Here, we refine the CP phenotype by supplementing clinical data with biological intermediates of microbial burden (levels of eight periodontal pathogens) and local inflammatory response (gingival crevicular fluid IL-1β) and derive periodontal complex traits (PCTs) via principal component analysis. PCTs were carried forward to GWAS (∼2.5 million markers) to identify PCT-associated loci among 975 European American adult participants of the Dental ARIC study. We sought to validate these findings for CP in the larger ARIC cohort (n = 821 participants with severe CP, 2031-moderate CP, 1914-healthy/mild disease) and an independent German sample including 717 aggressive periodontitis cases and 4210 controls. We identified six PCTs with distinct microbial community/IL-1β structures, although with overlapping clinical presentations. PCT1 was characterized by a uniformly high pathogen load, whereas PCT3 and PCT5 were dominated by Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, respectively. We detected genome-wide significant signals for PCT1 (CLEC19A, TRA, GGTA2P, TM9SF2, IFI16, RBMS3), PCT4 (HPVC1) and PCT5 (SLC15A4, PKP2, SNRPN). Overall, the highlighted loci included genes associated with immune response and epithelial barrier function. With the exception of associations of BEGAIN with severe and UBE3D with moderate CP, no other loci were associated with CP in ARIC or aggressive periodontitis in the German sample. Although not associated with current clinically determined periodontal disease taxonomies, upon replication and mechanistic validation these candidate loci may highlight dysbiotic microbial community structures and altered inflammatory/immune responses underlying biological sub-types of CP.