Age and Periodontal Health - Immunological View

Current scientific evidence for why periodontitis should be included in diabetes management

This Perspective provides a brief summary of the scientific evidence for the two-way links between periodontal diseases and hyperglycemia (diabetes mellitus [DM] and pre-DM). It delivers in a nutshell current scientific evidence for manifestations of hyperglycemia on periodontal health status and effects of periodontal diseases on blood glucose levels and in turn incidence, progression, and complications of diabetes. Of outmost importance is presentation of scientific evidence for the potential of routine periodontal treatment to lower blood glucose levels, providing a novel, economical tool in DM management. Non-surgical periodontal treatment ("deep cleaning") can be provided by dental hygienists or dentists in general dental offices, although severe cases should be referred to specialists. Such therapy can decrease the costs of DM care and other health care costs for people with DM. The great importance of a healthy oral cavity free of infection and subsequent inflammation - especially periodontitis that if untreated will cause loosening and eventually loss of affected teeth - has largely gone unnoticed by the medical community as the health care curricula are largely void of content regarding the bi-directional links between oral health and systemic health, despite elevation of blood glucose levels being an integral part of the general systemic inflammation response. The importance of keeping disease-free, natural teeth for proper biting and chewing, smiling, self-esteem, and pain avoidance cannot be overestimated. Medical and dental professionals are strongly encouraged to collaborate in patient-centered care for their mutual patients with - or at risk for - hyperglycemia.

Periodontitis-resistant and -susceptible matriline regulation of gingival transcriptome in nonhuman primates

OBJECTIVE

This report identified if gingival gene expression transcriptomes demonstrated unique profiles that discriminated periodontitis-susceptible (PDS) and periodontitis-resistant (PDR) animals in health and disease.

BACKGROUND

Nonhuman primates generally organize their social groups based upon matriline origin. We have used a multi-generational colony of rhesus macaques to identify matrilines presenting with significant differences in periodontitis (e.g., earlier age onset, greater prevalence, and severity).

METHODS

Animals from 12 to 23 years of age (n = 17; 8 - PDR, 9 - PDS) were entered into a ligature-induced periodontitis trial. Gingival biopsies were taken at baseline and 0.5, 1, 3, and 5 months post-ligation, and microarray analysis was used to quantify gene expression in samples at each time point.

RESULTS

Over 1000 genes showed significant (p < .01) differences in the PDR versus PDS animals at baseline. The frequency of differences generally decreased during the disease process, and increased with resolution (i.e., 5 months). A nearly 2:1 ratio of elevated gene levels was noted in baseline PDR samples that included up-regulated MMPs, Fc receptors, chemokines, interleukins, and innate immune receptors, and down-regulated genes particularly related to epithelial biology. Most dramatically, there was a skewed differential expression of adaptive immune response genes in the PDR and epithelial cell structure/function genes in PDS samples.

CONCLUSIONS

The results demonstrate substantive differences in gingival tissue response capacity/programming in PDR and PDS samples that may contribute to the differences in clinical outcomes related to the heritability of disease risk through matrilines.

DAMPs and alarmin gene expression patterns in aging healthy and diseased mucosal tissues

Introduction

Periodontitis is delineated by a dysbiotic microbiome at sites of lesions accompanied by a dysregulated persistent inflammatory response that undermines the integrity of the periodontium. The interplay of the altered microbial ecology and warning signals from host cells would be a critical feature for maintaining or re-establishing homeostasis in these tissues.

Methods

This study used a nonhuman primate model (Macaca mulatta) with naturally-occurring periodontitis (n = 34) and experimental ligature-induced periodontitis (n = 36) to describe the features of gene expression for an array of damage-associate molecular patterns (DAMPs) or alarmins within the gingival tissues. The animals were age stratified into: ≤3 years (Young), 7-12 years (Adolescent), 12-15 years (Adult) and 17-23 years (Aged). Gingival tissue biopsies were examined via microarray. The analysis focused on 51 genes representative of the DAMPs/alarmins family of host cell warning factors and 18 genes associated with tissue destructive processed in the gingival tissues. Bacterial plaque samples were collected by curette sampling and 16S rRNA gene sequences used to describe the oral microbiome.

Results

A subset of DAMPs/alarmins were expressed in healthy and naturally-occurring periodontitis tissues in the animals and suggested local effects on gingival tissues leading to altered levels of DAMPs/alarmins related to age and disease. Significant differences from adult healthy levels were most frequently observed in the young and adolescent animals with few representatives in this gene array altered in the healthy aged gingival tissues. Of the 51 target genes, only approximately ⅓ were altered by ≥1.5-fold in any of the age groups of animals during disease, with those increases observed during disease initiation. Distinctive positive and negative correlations were noted with the DAMP/alarmin gene levels and comparative expression changes of tissue destructive molecules during disease across the age groups. Finally, specific correlations of DAMP/alarmin genes and relative abundance of particular microbes were observed in health and resolution samples in younger animals, while increased correlations during disease in the older groups were noted.

Conclusions

Thus, using this human-like preclinical model of induced periodontitis, we demonstrated the dynamics of the activation of the DAMP/alarmin warning system in the gingival tissues that showed some specific differences based on age.

Sex effects on gingival transcriptomic patterns during initiation, progression, and resolution of periodontitis

BACKGROUND

The prevalence and severity of periodontitis demonstrates altered population distribution with age, sex, and race and ethnicity. While males exhibit greater frequency of disease, particularly with aging, the underlying basis for this observation remains obscure.

OBJECTIVE

This study used a nonhuman primate (Macaca mulatta) model of experimental ligature-induced periodontitis in adult animals to evaluate gingival transcriptomic differences stratified based upon sex of the animal.

METHODS

The 18 animals represented humans ages 40-80 years, with gingival tissue samples obtained at baseline, 0.5 months (initiation), 1 and 3 months (progression), and at 5 months that were 60 days after ligature removal for clinical disease resolution. Microarray analysis was used to quantify gene expression profiles in the gingival tissues.

RESULTS

The results demonstrated clear gene expression differences in healthy (baseline) tissues between the sexes, with elevations in females associated with immune responses and elevation in males related to tissue structural genes. With disease initiation, fewer genes differed between the sexes, while these differences were significantly increased in progressing disease and resolution, particularly in male animals. Overexpressed biological processes showed tissue structural/functional genes at initiation, with host response pathways altered during disease progression. Resolution samples generally demonstrated biological processes of cellular metabolism that differed from baseline healthy samples.

CONCLUSION

The transcriptomic findings support sex as a biological variable in periodontitis using a nonhuman primate model of experimental periodontitis.

Microbial metabolites in the pathogenesis of periodontal diseases: a narrative review

The purpose of this narrative review is to highlight the importance of microbial metabolites in the pathogenesis of periodontal diseases. These diseases, involving gingivitis and periodontitis are inflammatory conditions initiated and maintained by the polymicrobial dental plaque/biofilm. Gingivitis is a reversible inflammatory condition while periodontitis involves also irreversible destruction of the periodontal tissues including the alveolar bone. The inflammatory response of the host is a natural reaction to the formation of plaque and the continuous release of metabolic waste products. The microorganisms grow in a nutritious and shielded niche in the periodontal pocket, protected from natural cleaning forces such as saliva. It is a paradox that the consequences of the enhanced inflammatory reaction also enable more slow-growing, fastidious, anaerobic bacteria, with often complex metabolic pathways, to colonize and thrive. Based on complex food chains, nutrient networks and bacterial interactions, a diverse microbial community is formed and established in the gingival pocket. This microbiota is dominated by anaerobic, often motile, Gram-negatives with proteolytic metabolism. Although this alternation in bacterial composition often is considered pathologic, it is a natural development that is promoted by ecological factors and not necessarily a true "dysbiosis". Normal commensals are adapting to the gingival crevice when tooth cleaning procedures are absent. The proteolytic metabolism is highly complex and involves a number of metabolic pathways with production of a cascade of metabolites in an unspecific manner. The metabolites involve short chain fatty acids (SCFAs; formic, acetic, propionic, butyric, and valeric acid), amines (indole, scatole, cadaverine, putrescine, spermine, spermidine) and gases (NH₃, CO, NO, H₂S, H₂). A homeostatic condition is often present between the colonizers and the host response, where continuous metabolic fluctuations are balanced by the inflammatory response. While it is well established that the effect of the dental biofilm on the host response and tissue repair is mediated by microbial metabolites, the mechanisms behind the tissue destruction (loss of clinical attachment and bone) are still poorly understood. Studies addressing the functions of the microbiota, the metabolites, and how they interplay with host tissues and cells, are therefore warranted.

Cellular Senescence and Periodontitis: Mechanisms and Therapeutics

Periodontitis is a chronic inflammatory disease which increases in prevalence and severity in the older population. Aging is a leading risk factor for periodontitis, which exacerbates alveolar bone loss and results in tooth loss in the elderly. However, the mechanism by which aging affects periodontitis is not well understood. There is considerable evidence to suggest that targeting cellular senescence could slow down the fundamental aging process, and thus alleviate a series of age-related pathological conditions, likely including alveolar bone loss. Recently, it has been discovered that the senescent cells accumulate in the alveolar bone and promote a senescence-associated secretory phenotype (SASP). Senescent cells interacting with bacteria, together with secreted SASP components altering the local microenvironment and inducing paracrine effects in neighboring cells, exacerbate the chronic inflammation in periodontal tissue and lead to more alveolar bone loss. This review will probe into mechanisms underlying excessive alveolar bone loss in periodontitis with aging and discuss potential therapeutics for the treatment of alveolar bone loss targeting cellular senescence and the SASP. Inspecting the relationship between cellular senescence and periodontitis will lead to new avenues of research in this field and contribute to developing potential translatable clinical interventions to mitigate or even reverse the harmful effects of aging on oral health.

Radiographically screened periodontitis is associated with deteriorated oral-health quality of life: A cross-sectional study

Periodontitis is greatly related to worse perceived oral health-related quality of life (OHRQoL), yet this association has never been explored using radiographically screened periodontal bone loss. Here we have radiographically screened patients for periodontitis via a validated method and assessed its association with measures of OHRQoL. From a total of 10,267 participants (6,112 females and 4,155 males), self-reported general health questionnaire, body mass index, self-reported oral health behaviours, panoramic x-rays and the oral health impact profile (OHIP-14) were gathered. Radiographically screened periodontitis was measured through a radiographic-based periodontal bone loss (R-PBL) approach. We compared the respective variables according to the R-PBL status and explored using multiple logistic regression adjusted for the significant variables. Overall, patients with periodontitis shown significantly different sociodemographic, health measures and oral hygiene characteristics. All domains of the OHIP-14 were significantly worsened in the periodontitis group, and further confirmed through adjusted logistic regression (p<0.001). Active smoking, number of missing teeth, sex and age were the most impactful variables in this relationship. Our results demonstrate the existence of a link between radiographically screened periodontitis and OHRQoL, mostly upheld by active smoking, number of missing teeth, sex and age.

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.

The niche-specialist and age-related oral microbial ecosystem: crosstalk with host immune cells in homeostasis

Although characterization of the baseline oral microbiota has been discussed, the current literature seems insufficient to draw a definitive conclusion on the interactions between the microbes themselves or with the host. This study focuses on the spatial and temporal characteristics of the oral microbial ecosystem in a mouse model and its crosstalk with host immune cells in homeostasis. The V3V4 regions of the 16S rRNA gene of 20 samples from four niches (tongue, buccal mucosa, keratinized gingiva and hard palate) and 10 samples from two life stages (adult and old) were analysed. Flow cytometry (FCM) was used to investigate the resident immune cells. The niche-specialist and age-related communities, characterized based on the microbiota structure, interspecies communications, microbial functions and interactions with immune cells, were addressed. The phylum Firmicutes was the major component in the oral community. The microbial community profiles at the genus level showed that the relative abundances of the genera Bacteroides, Lactobacillus and Porphyromonas were enriched in the gingiva. The abundance of the genera Streptococcus, Faecalibaculum and Veillonella was increased in palatal samples, while the abundance of Neisseria and Bradyrhizobium was enriched in buccal samples. The genera Corynebacterium, Stenotrophomonas, Streptococcus and Fusobacterium were proportionally enriched in old samples, while Prevotella and Lacobacillus were enriched in adult samples. Network analysis showed that the genus Lactobacillus performed as a central node in the buccal module, while in the gingiva module, the central nodes were Nesterenkonia and Hydrogenophilus. FCM showed that the proportion of Th1 cells in the tongue samples (38.18 % [27.03–49.34 %]) (mean [range]) was the highest. The proportion of γδT cells in the buccal mucosa (25.82 % [22.1–29.54 %]) and gingiva (20.42 % [18.31–22.53 %]) samples was higher (P<0.01) than those in the palate (14.18 % [11.69–16.67 %]) and tongue (9.38 % [5.38–13.37 %] samples. The proportion of Th2 (31.3 % [16.16–46.44 %]), Th17 (27.06 % [15.76–38.36 %]) and Treg (29.74 % [15.71–43.77 %]) cells in the old samples was higher than that in the adult samples (P<0.01). Further analysis of the interplays between the microbiomes and immune cells indicated that Th1 cells in the adult group, nd Th2, Th17 and Treg cells in the old group were the main immune factors strongly associated with the oral microbiota. For example, Th2, Th17 and Treg cells showed a significantly positive correlation with age-related microorganisms such as Sphingomonas, Streptococcus and Acinetobacter, while Th1 cells showed a negative correlation. Another positive correlation occurred between Th1 cells and several commensal microbiomes such as Lactobacillus, Jeotgalicoccus and Sporosarcina. Th2, Th17 and Treg cells showed the opposite trend. Together, our findings identify the niche-specialist and age-related characteristics of the oral microbial ecosystem and the potential associations between the microbiomes and the mucosal immune cells, providing critical insights into mucosal microbiology.

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.

A Tale of Two Fimbriae: How Invasion of Dendritic Cells by Porphyromonas gingivalis Disrupts DC Maturation and Depolarizes the T-Cell-Mediated Immune Response

Porphyromonas gingivalis (P. gingivalis) is a unique pathogen implicated in severe forms of periodontitis (PD), a disease that affects around 50% of the US population. P. gingivalis is equipped with a plethora of virulence factors that it uses to exploit its environment and survive. These include distinct fimbrial adhesins that enable it to bind to other microbes, colonize inflamed tissues, acquire nutrients, and invade cells of the stroma and immune system. Most notable for this review is its ability to invade dendritic cells (DCs), which bridge the innate and adaptive immune systems. This invasion process is tightly linked to the bridging functions of resultant DCs, in that it can disable (or stimulate) the maturation function of DCs and cytokines that are secreted. Maturation molecules (e.g., MHCII, CD80/CD86, CD40) and inflammatory cytokines (e.g., IL-1b, TNFa, IL-6) are essential signals for antigen presentation and for proliferation of effector T-cells such as Th17 cells. In this regard, the ability of P. gingivalis to coordinately regulate its expression of major (fimA) and minor (mfa-1) fimbriae under different environmental influences becomes highly relevant. This review will, therefore, focus on the immunoregulatory role of P. gingivalis fimbriae in the invasion of DCs, intracellular signaling, and functional outcomes such as alveolar bone loss and immune senescence.

[Dynamic Microbial Shifts and Functional Analysis of Saliva Microbial Communities with Caries Children]

Objective

To observe the dynamic changes in the salivary microbiota of children with dental caries and those who were caries-free and to analyze the functional differences in the oral microecology of the two groups during the course of sugar metabolism and the synthesis and transport of multiple amino acids.

Methods

Ten children with dental caries and 10 caries-free children were enrolled. We employed Illumina metagenomics technology to analyze the composition and function of salivary microbiome in children with and without caries. Six months later, PacBio single-molecule long-read sequencing technology was used to analyze the changes over time in the oral microbial communities of the two groups. We studied the patterns of change in the oral microbial communities under diseased or healthy conditions and attempted to offer a comprehensive interpretation of children's oral microbiota in terms of its composition and functions.

Results

The composition of the oral microbiota of children with or without dental caries changed significantly over time. At the phylum level, changing trends in the salivary microbial communities of children with dental caries were in line with those in caries-free children. In these microbial communities, increased proportions of Firmicutes and decreased proportions of Actinobacteria and Bacteroidetes were found in the two groups. At the genus level, however, the two groups showed significantly different changes of the salivary microbial communities. Upward trends in the abundance of Lactobacillus, Methylobacterium, and Megasphaera were found in the caries group, while the abundance of these genera in the caries-free group showed downward trends. At the species level, L. fermentum, L. gasseri, L. oris, S. downei, and some other species belonging to the genus Lactobacillus showed upward trends in the saliva of children with caries, while they consistently stayed at a relative low level of abundance in caries-free children. The abundance of S. gordonii and S. mutans decreased to a certain extent in children with dental caries, but the abundance of S. gordonii and S. mutans in caries-free children were always at a low level. Species such as S. mutans and C. gracilis were positively correlated to the sum of decayed, missing and filled teeth (dmft), while N. flavescens was negatively correlated to dmft. gltA, icd, and mqo, the key genes related to tricarboxylic acid (TCA) cycle, gudB, a glutamate synthesis-related gene, and argAB/C/J, arginine synthesis-related genes, were significantly increased in caries-free children. In addition, the abundance of the NADH dehydrogenase-related gene nuoB/C/D/E/H/I/J/K/L/M in the electron transport chain increased significantly in caries-free children.

Conclusion

Dynamic changes were found in the oral microbiota of children with or without caries. The trends of microbial shifts over time were associated with the oral health status. Oxidative phosphorylation and the synthesis and transport of amino acids such as glutamate and arginine in the oral microecology were more active in caries-free children.

Metabolomic Evaluation of Chronic Periodontal Disease in Older Adults

Periodontal disease is an infectious inflammatory disease related to the destruction of supporting tissues of the teeth, leading to a functional loss of the teeth. Inflammatory molecules present in the exudate are catalyzed and form different metabolites that can be identified and quantified. Thus, we evaluated the inflammatory exudate present in crevicular fluid to identify metabolic biological markers for diagnosing chronic periodontal disease in older adults. Research participants were selected from long-term institutions in Brazil. Participants were individuals aged 65 years or older, healthy, or with chronic periodontal disease. Gas chromatography/mass spectrometry was used to evaluate potential biomarkers in 120 crevicular fluid samples. We identified 969 metabolites in the individuals. Of these, 15 metabolites showed a variable importance with projection score > 1 and were associated with periodontal disease. Further analysis showed that among the 15 metabolites, two (5-aminovaleric acid and serine, 3TMS derivative) were found at higher concentrations in the crevicular fluid, indicating their potential diagnostic power for periodontal disease in older adults. Our findings indicated that some metabolites are present at high concentrations in the crevicular fluid in older adults with periodontal disease and can be used as biomarkers of periodontal disease.

Neutrophils Orchestrate the Periodontal Pocket

The subgingival biofilm attached to tooth surfaces triggers and maintains periodontitis. Previously, late-onset periodontitis has been considered a consequence of dysbiosis and a resultant polymicrobial disruption of host homeostasis. However, a multitude of studies did not show "healthy" oral microbiota pattern, but a high diversity depending on culture, diets, regional differences, age, social state etc. These findings relativise the aetiological role of the dysbiosis in periodontitis. Furthermore, many late-onset periodontitis traits cannot be explained by dysbiosis; e.g. age-relatedness, attenuation by anti-ageing therapy, neutrophil hyper-responsiveness, and microbiota shifting by dysregulated immunity, yet point to the crucial role of dysregulated immunity and neutrophils in particular. Furthermore, patients with neutropenia and neutrophil defects inevitably develop early-onset periodontitis. Intra-gingivally injecting lipopolysaccharide (LPS) alone causes an exaggerated neutrophil response sufficient to precipitate experimental periodontitis. Vice versa to the surplus of LPS, the increased neutrophil responsiveness characteristic for late-onset periodontitis can effectuate gingiva damage likewise. The exaggerated neutrophil extracellular trap (NET) response in late-onset periodontitis is blameable for damage of gingival barrier, its penetration by bacteria and pathogen-associated molecular patterns (PAMPs) as well as stimulation of Th17 cells, resulting in further neutrophil activation. This identifies the dysregulated immunity as the main contributor to periodontal disease.

Severity of Dementia Is Associated with Increased Periodontal Inflamed Surface Area: Home Visit Survey of People with Cognitive Decline Living in the Community

No studies have measured the periodontal inflamed surface area in people with dementia, although periodontal disease is a major health issue in this group. This study aimed to determine the relationship between dementia severity and periodontal inflamed surface area. An interdisciplinary team, including a dentist and psychiatrist, conducted an in-home survey of older people living in the community. This cross-sectional study was designed as part of a larger cohort study. The interdisciplinary team visited 198 individuals with cognitive decline. We surveyed the clinical dementia rating, periodontal inflamed surface area, number of teeth, and other health issues. We used multiple linear regression analysis to assess the 75 people who were able to take part in all the visits. Number of teeth (Beta = 0.479, p < 0.001), clinical dementia rating (Beta = 0.258, p = 0.013), and age (Beta = 0.250, p = 0.017) were independently associated with periodontal inflamed surface area after adjusting for biological sex, depression, diabetes, collagen disease, visual disorder, and osteoporosis medication. To make communities more dementia-friendly, we must protect older people with dementia from developing poor oral health, which may require home visits for dental assessment.

Probiotics in the Management of Gingivitis and Periodontitis. A Review

In the management of intestinal health problems, the targeted use of probiotic microorganisms is a common therapeutic measure with a long-standing tradition. In clinical dentistry however, probiotics-based therapy is still a rather new and developing field, whose usefulness for the control of gingivitis and periodontitis has been questioned by recent meta-analyses and systematic reviews. The purpose of the subsequent descriptive review is to provide an introduction to the concept of probiotic microorganisms and their multifaceted health-promoting interactions with the human host and microbial competitors, followed by a detailed comparison of the results of available controlled clinical trials assessing the use of probiotics in the control of gingival and periodontal inflammations. It aims at contributing to a deeper understanding of the unique capabilities of probiotics to resolve chronic plaque-induced inflammation even in the absence of mechanical plaque control and will discuss how possible misconceptions about the rationale for using probiotics may have led to the present controversies about their usefulness as a therapeutic option.

Treatment of Residual Periodontal Pockets Using a Hyaluronic Acid-Based Gel: A 12 Month Multicenter Randomized Triple-Blinded Clinical Trial

The aim of the present study was to evaluate the adjunctive effect of hyaluronic acid (HA) gel in the treatment of residual periodontal pockets over a 12-month period. Periodontal patients presenting at least one residual periodontal pocket 5-9 mm of depth in the anterior area were recruited from six university-based centers. Each patient was randomly assigned to subgingival instrumentation (SI) with the local adjunctive use of HA for test treatment or adjunctive use of local placebo for control treatment at baseline and after 3 months. Clinical parameters ( )probing depth (PD), bleeding on probing (BoP), plaque index (PI), recession (REC), clinical attachment level (CAL)) and microbiological samples for the investigation of the total bacterial count (TBC) and presence of specific bacterial species (Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Fusobacterium nucleatum) were taken at baseline and every 3 months, until study termination. PD was determined as the primary outcome variable. From a total of 144 enrolled, 126 participants (53 males, 73 females) completed the entire protocol. Both treatments resulted in statistically significant clinical and microbiological improvements compared to baseline. Although the local application of HA showed a tendency for better results, there was a lack of statistically significant differences between the groups.

Porphyromonas gingivalis Provokes Exosome Secretion and Paracrine Immune Senescence in Bystander Dendritic Cells

Periodontitis is a disease of ageing or inflammaging, and is comorbid with other more severe age-related chronic diseases. With advanced age comes an increase in accumulation of senescent cells that release soluble and insoluble pro-inflammatory factors collectively termed the senescence associated secretory phenotype (SASP). In the present report, we examined whether immune cells typical of those at the oral mucosa-microbe interface, are vulnerable to cellular senescence (CS) and the role of dysbiotic oral pathogen Porphyromonas gingivalis. Bone marrow-derived dendritic cells (DCs) from young (yDCs) and old (oDCs) mice were co-cultured in vitro with CS inducer doxorubicin or P.gingivalis (Pg), plus or minus senolytic agent rapamycin. CS profiling revealed elevated CS mediators SA-β-Gal, p16 ^INK4A, p53, and p21^Waf1/Clip1 in oDCs, or yDCs in response to doxorubicin or P. gingivalis, reversible with rapamycin. Functional studies indicate impaired maturation function of oDCs, and yDC exposed to P. gingivalis; moreover, OVA-driven proliferation of CD4+ T cells from young OTII transgenic mice was impaired by oDCs or yDCs+Pg. The SASP of DCs, consisting of secreted exosomes and inflammasome-related cytokines was further analyzed. Exosomes of DCs cocultured with P. gingivalis (PgDCexo) were purified, quantitated and characterized. Though typical in terms of size, shape and phenotype, PgDCexo were 2-fold greater in number than control DCs, with several important distinctions. Namely, PgDCexo were enriched in age-related miRNAs, and miRNAs reported to disrupt immune homeostasis through negative regulation of apoptosis and autophagy functions. We further show that PgDCexo were enriched in P. gingivalis fimbrial adhesin protein mfa1 and in inflammasome related cytokines IL-1β, TNFα and IL-6. Functionally PgDCexo were readily endocytosed by recipient yDCs, amplifying functional impairment in maturation and ability to promote Ova-driven proliferation of OTII CD4+ T cells from young mice. In conclusion P. gingivalis induces premature (autocrine) senescence in DCs by direct cellular invasion and greatly amplifies senescence, in paracrine, of bystander DCs by secretion of inflammatory exosomes. The implications of this pathological pathway for periodontal disease in vivo is under investigation in mouse models.

Transcriptomic phases of periodontitis lesions using the nonhuman primate model

We used a nonhuman primate model of ligature-induced periodontitis to identify patterns of gingival transcriptomic after changes demarcating phases of periodontitis lesions (initiation, progression, resolution). A total of 18 adult Macaca mulatta (12-22 years) had ligatures placed (premolar, 1st molar teeth) in all 4 quadrants. Gingival tissue samples were obtained (baseline, 2 weeks, 1 and 3 months during periodontitis and at 5 months resolution). Gene expression was analyzed by microarray [Rhesus Gene 1.0 ST Array (Affymetrix)]. Compared to baseline, a large array of genes were significantly altered at initiation (n = 6049), early progression (n = 4893), and late progression (n = 5078) of disease, with the preponderance being up-regulated. Additionally, 1918 genes were altered in expression with disease resolution, skewed towards down-regulation. Assessment of the genes demonstrated specific profiles of epithelial, bone/connective tissue, apoptosis/autophagy, metabolism, regulatory, immune, and inflammatory responses that were related to health, stages of disease, and tissues with resolved lesions. Unique transcriptomic profiles occured during the kinetics of the periodontitis lesion exacerbation and remission. We delineated phase specific gene expression profiles of the disease lesion. Detection of these gene products in gingival crevicular fluid samples from human disease may contribute to a better understanding of the biological dynamics of the disease to improve patient management.

The Role of Neutrophil Extracellular Traps in Periodontitis

Periodontitis is a chronic, destructive disease of periodontal tissues caused by multifaceted, dynamic interactions. Periodontal bacteria and host immunity jointly contribute to the pathological processes of the disease. The dysbiotic microbial communities elicit an excessive immune response, mainly by polymorphonuclear neutrophils (PMNs). As one of the main mechanisms of PMN immune response in the oral cavity, neutrophil extracellular traps (NETs) play a crucial role in the initiation and progression of late-onset periodontitis. NETs are generated and released by neutrophils stimulated by various irritants, such as pathogens, host-derived mediators, and drugs. Chromatin and proteins are the main components of NETs. Depending on the characteristics of the processes, three main pathways of NET formation have been described. NETs can trap and kill pathogens by increased expression of antibacterial components and identifying and trapping bacteria to restrict their spread. Moreover, NETs can promote and reduce inflammation, inflicting injuries on the tissues during the pro-inflammation process. During their long-term encounter with NETs, periodontal bacteria have developed various mechanisms, including breaking down DNA of NETs, degrading antibacterial proteins, and impacting NET levels in the pocket environment to resist the antibacterial function of NETs. In addition, periodontal pathogens can secrete pro-inflammatory factors to perpetuate the inflammatory environment and a friendly growth environment, which are responsible for the progressive tissue damage. By learning the strategies of pathogens, regulating the periodontal concentration of NETs becomes possible. Some practical ways to treat late-onset periodontitis are reducing the concentration of NETs, administering anti-inflammatory therapy, and prescribing broad-spectrum and specific antibacterial agents. This review mainly focuses on the mechanism of NETs, pathogenesis of periodontitis, and potential therapeutic approaches based on interactions between NETs and periodontal pathogens.

Influence of Micronutrient Intake, Sociodemographic, and Behavioral Factors on Periodontal Status of Adults Assisted by a Public Health Care System in Brazil: A Cross-Sectional Multivariate Analysis

The lack of access to a balanced diet, rich in vitamins and minerals, can predispose people to inflammatory diseases such as obesity, diabetes mellitus, and periodontitis. We aimed to evaluate the relationship between micronutrient intake, sociodemographic behavioral characteristics, and periodontal health in adults assisted by a public health care system. Participants (n = 450) answered a food frequency questionnaire and were submitted to anthropometric and oral clinical examinations. Principal component analysis was used to summarize the number of components emerging from 17-micronutrient intake. Subsequently, cluster analysis was employed. The prevalence of at least one periodontal pocket ≥ 4 mm was 67.4%. Three clusters were identified according to periodontal status. Cluster 1 "poor periodontal status" was characterized by older individuals (n = 202; 85% females) with poor periodontal status, lower education level, mainly smokers with non-transmissible chronic diseases (NTCD), with lower energy, omega-3, fiber, Zn, K, Cu, and vitamin C intake. Cluster 3 "healthy periodontal status" included younger individuals (n = 54) with the healthiest periodontal status, a higher education level, without NTCD, and with higher energy, omega-3, fiber, Zn, calcium, retinol, and riboflavin intake. Cluster 2 was labeled as "intermediate periodontal status". Micronutrient ingestion was associated with periodontal status and may be considered in health promotion actions for low-income populations.

Endpoints of active periodontal therapy

Aim

Position paper on endpoints of active periodontal therapy for designing treatment guidelines. The question was as follows: How are, for an individual patient, commonly applied periodontal probing measures—recorded after active periodontal therapy—related to (a) stability of clinical attachment level, (b) tooth survival, (c) need for re‐treatment or (d) oral health‐related quality of life.

Methods

A literature search was conducted in Ovid MEDLINE(R) and Epub Ahead of Print, In‐Process & Other Non‐Indexed Citations and Daily <1946 to 07 June 2019>.

Results

A total of 94 papers were retrieved. From the literature search, it was found that periodontitis patients with a low proportion of deep residual pockets after active periodontal therapy are more likely to have stability of clinical attachment level over a follow‐up time of ≥1 year. Other supporting literature confirms this finding and additionally reports, at the patient level, that probing pocket depths ≥6 mm and bleeding on probing scores ≥30% are risks for tooth loss. There is lack of evidence that periodontal probing measures after completion of active periodontal treatment are tangible to the patient.

Conclusions

Based on literature and biological plausibility, it is reasonable to state that periodontitis patients with a low proportion of residual periodontal pockets and little inflammation are more likely to have stability of clinical attachment levels and less tooth loss over time. Guidelines for periodontal therapy should take into consideration (a) long‐term tangible patient outcomes, (b) that shallow pockets (≤4 mm) without bleeding on probing in patients with <30% bleeding sites are the best guarantee for the patient for stability of his/her periodontal attachment, (c) patient heterogeneity and patient changes in immune response over time, and (d) that treatment strategies include lifestyle changes of the patient. Long‐term large population‐based and practice‐based studies on the efficacy of periodontal therapies including both clinical and patient‐reported outcomes (PROs) need to be initiated, which include the understanding that periodontitis is a complex disease with variation of inflammatory responses due to environment, (epi)genetics, lifestyle and ageing. Involving people living with periodontitis as co‐researchers in the design of these studies would also help to improve their relevance.

Biological Aging and Periodontal Disease: Analysis of NHANES (2001-2002)

INTRODUCTION

Periodontitis is a chronic inflammatory disease caused by multiple potential contributing factors such as bacterial biofilm infection of the tissues surrounding the teeth and environmental determinants and a dysregulated host response for modifying and resolving the inflammation. Because periodontal disease is a major public health concern with substantial increases in the prevalence and severity in aging populations, previous studies of periodontitis tended to approach the disease as an age-associated outcome across the life span. However, few investigations have considered that, as a chronic noncommunicable disease, periodontitis may not simply be a disease that increases with age but may contribute to more rapid biologic aging.

OBJECTIVES

Increasing population data supports the potential disconnect between chronological aging and biologic aging, which would contribute to the heterogeneity of aging phenotypes within chronologic ages across populations. Thus, our aim was to test whether periodontal disease affects biological aging across the life span.

METHODS

The prevalence of periodontitis in the adult US population is a portion of the assessment of the National Health and Nutrition Examination Survey (NHANES), which has been ongoing since 1971 through 2-y cycles sampling populations across the country. We used NHANES 2001-2002 to test the hypothesis that the presence/severity of periodontal disease as an exposure variable would negatively affect telomere length, a measure of biological aging, and that this relationship is modified by factors that also affect the progression of periodontitis, such as sex, race/ethnicity, and smoking.

RESULTS

The data demonstrated a significant impact of periodontitis on decreasing telomere lengths across the life span. These differences were modulated by age, sex, race/ethnicity, and smoking within the population.

CONCLUSION

The findings lay the groundwork for future studies documenting broader effects on biological aging parameters as well as potential intervention strategies for periodontitis in driving unhealthy aging processes.

KNOWLEDGE TRANSFER STATEMENT

Periodontitis is a chronic inflammatory disease and dysregulated host response. Shortening of telomeres is a reflection of biologic aging. Decreased telomere lengths with periodontitis are seemingly related to chronic infection and persistent local and systemic inflammation. These findings suggest that periodontitis is not simply a disease of aging but may also transmit chronic systemic signals that could affect more rapid biological aging. Clinicians can use this outcome to recognize the role of periodontitis in driving unhealthy aging processes in patients.

Oral microbiome interactions with gingival gene expression patterns for apoptosis, autophagy and hypoxia pathways in progressing periodontitis

Oral mucosal tissues must react with and respond to microbes comprising the oral microbiome ecology. This study examined the interaction of the microbiome with transcriptomic footprints of apoptosis, autophagy and hypoxia pathways during periodontitis. Adult Macaca mulatta (n = 18; 12-23 years of age) exhibiting a healthy periodontium at baseline were used to induce progressing periodontitis through ligature placement around premolar/molar teeth. Gingival tissue samples collected at baseline, 0·5, 1 and 3 months of disease and at 5 months for disease resolution were analysed via microarray. Bacterial samples were collected at identical sites to the host tissues and analysed using MiSeq. Significant changes in apoptosis and hypoxia gene expression occurred with initiation of disease, while autophagy gene changes generally emerged later in disease progression samples. These interlinked pathways contributing to cellular homeostasis showed significant correlations between altered gene expression profiles in apoptosis, autophagy and hypoxia with groups of genes correlated in different directions across health and disease samples. Bacterial complexes were identified that correlated significantly with profiles of host genes in health, disease and resolution for each pathway. These relationships were more robust in health and resolution samples, with less bacterial complex diversity during disease. Using these pathways as cellular responses to stress in the local periodontal environment, the data are consistent with the concept of dysbiosis at the functional genomics level. It appears that the same bacteria in a healthy microbiome may be interfacing with host cells differently than in a disease lesion site and contributing to the tissue destructive processes.

Future directions for studying resilience of the oral ecosystem

The oral ecosystem is shaped by complex interactions between systemic health disease and the resident oral microbiota. Research in the last two decades has produced datasets describing the genetics and physiology of the host and the oral microbiome in health and disease. There are inter-individual differences in the ability to tolerate oral disease-promoting challenges. Identification of the key factors that drive a healthy and resilient oral ecosystem is urgently needed. So far, progress is being made towards replicating the host-microbiota interplay in vitro. Clinical studies may shed light on the mechanisms of oral health resilience. However, most clinical studies are cross-sectional and are insufficient for understanding resilience or for identifying biomarkers that correlate with the point of transition from oral health to dysbiosis. Mathematical and computational models, including artificial intelligence approaches, offer an opportunity to inform the design of clinical studies by identifying key biomarkers and interaction networks in complex datasets and predicting important parameters. This paper discusses some of the challenges and opportunities for understanding the biological basis of resilience of the oral ecosystem. It discusses the current status and challenges, and proposes a way forward to better understand resilience towards oral diseases.

NETs Are Double-Edged Swords with the Potential to Aggravate or Resolve Periodontal Inflammation

Periodontitis is a general term for diseases characterised by inflammatory destruction of tooth-supporting tissues, gradual destruction of the marginal periodontal ligament and resorption of alveolar bone. Early-onset periodontitis is due to disturbed neutrophil extracellular trap (NET) formation and clearance. Indeed, mutations that inactivate the cysteine proteases cathepsin C result in the massive periodontal damage seen in patients with deficient NET formation. In contrast, exaggerated NET formation due to polymorphonuclear neutrophil (PMN) hyper-responsiveness drives the pathology of late-onset periodontitis by damaging and ulcerating the gingival epithelium and retarding epithelial healing. Despite the gingival regeneration, periodontitis progression ends with almost complete loss of the periodontal ligament and subsequent tooth loss. Thus, NETs help to maintain periodontal health, and their dysregulation, either insufficiency or surplus, causes heavy periodontal pathology and edentulism.

Is periodontal disease a risk factor for severe COVID-19 illness?

Periodontal disease (PD) comprises a group of diseases involving inflammatory aspects of the host and dysbiotic events that affect periodontal tissues and could have systemic implications. Diverse factors and comorbidities have been closely associated with PD such as diabetes, obesity, aging, hypertension, and so on; although, underlying mechanisms or causal associations have not been established completely. Interestingly, these same factors have been widely associated with progression or severe coronavirus disease 2019 (COVID-19), an illness caused by coronavirus SARS-CoV-2. Since inflammatory and dysbiotic factors as well as comorbidities affect systemic health, it is possible that periodontal status indicates the risk of complication of COVID-19. However, assessment of oral health history including periodontal status in COVID-19 patients has not been reported. Knowing PD is associated with severe COVID-19 could help identify risk groups and establish pertinent recommendations.

Microglial response to experimental periodontitis in a murine model of Alzheimer's disease

Periodontal disease (PD) has been suggested to be a risk factor for Alzheimer's disease (AD). We tested the impact of ligature-induced PD on 5xFAD mice and WT littermates. At baseline, 5xFAD mice presented significant alveolar bone loss compared to WT mice. After the induction of PD, both WT and 5xFAD mice experienced alveolar bone loss. PD increased the level of Iba1-immunostained microglia in WT mice. In 5xFAD mice, PD increased the level of insoluble Aβ42. The increased level in Iba1 immunostaining that parallels the accumulation of Aβ in 5xFAD mice was not affected by PD except for a decrease in the dentate gyrus. Analysis of double-label fluorescent images showed a decline in Iba1 in the proximity of Aβ plaques in 5xFAD mice with PD compared to those without PD suggesting a PD-induced decrease in plaque-associated microglia (PAM). PD reduced IL-6, MCP-1, GM-CSF, and IFN-γ in brains of WT mice and reduced IL-10 in 5xFAD mice. The data demonstrated that PD increases neuroinflammation in WT mice and disrupts the neuroinflammatory response in 5xFAD mice and suggest that microglia is central to the association between PD and AD.

Increase in serum and salivary neutrophil gelatinase-associated lipocalin levels with increased periodontal inflammation

OBJECTIVE

This study aimed to determine serum and salivary levels of neutrophil gelatinase-associated lipocalin (NGAL) and evaluate NGAL correlation with key anti-interleukin 10 (IL-10) and pro-inflammatory (IL-1β) cytokines in different severities of periodontal diseases. We also calculated the systemic inflammation using the periodontal inflamed surface area (PISA) to evaluate its correlation with NGAL in the study groups.

METHODOLOGY

Eighty systemically healthy and non-smoking individuals were separated into four groups of 20: clinically healthy (Group 1), gingivitis (Group 2), stage I generalized periodontitis (Group 3, Grade A), and stage III generalized periodontitis (Group 4, Grade A). Sociodemographic characteristics and periodontal parameters were recorded, and PISA was calculated. The serum and salivary levels of interleukin (IL)-1β, IL-10, and NGAL were determined using the enzyme-linked immunosorbent assay (ELISA).

RESULTS

We observed a significant increase in serum and salivary NGAL levels from healthy to periodontitis groups (p=0.000). Group 2 presented significantly higher serum and salivary IL-10 levels and salivary IL-1β levels than Group 3 (p=0.000). Serum and salivary parameters (IL-1β, IL-10, and NGAL levels) were strongly positively correlated to periodontal parameters and PISA values (p=0.000). Groups 2 and 3 showed overlapping PISA values.

CONCLUSION

The overlapping PISA values found in Groups 2 and 3 suggest that gingivitis might progress to a systemic inflammatory burden somewhat comparable to stage I periodontitis. This finding is supported by the higher serum and salivary cytokines/mediators levels in the gingivitis group than in stage I periodontitis group. Serum and salivary NGAL levels increased proportionally to disease severity and PISA. NGAL seems to play a role in the pathogenesis of periodontal disease, within the limitation of our study.

Current concepts and an alternative perspective on periodontal disease

Background

Epidemiological data from countries worldwide show a consistent pattern implying that a fraction of around 10% of those over 40–50 years in all populations will exhibit severe periodontitis with the potential risk of losing teeth during their life-time. The subgingival microbiota shows striking similarities between populations irrespective of disease severity and can only marginally explain the clinical pattern. It is also difficult to explain this pattern by genetic and acquired risk factors such as systemic disease (e.g. diabetes) or habits (e.g. smoking) even if they may have a confounding effect on the disease.

Main text

Inflammation of the gingiva appears to be a normal and physiological response to the presence of commensal bacteria along the gingival crevice and in the dental biofilm. Over many years of exposure to the dental biofilm, the chronic inflammation in the gingiva gradually results in a loss of attachment and bone loss. Numerous laboratory and clinical studies have provided insight into the potential role of determinants that are associated with periodontitis. However, it has been difficult to relate the findings to the pattern of the distribution of the disease observed in epidemiological studies. We propose a simple and parsimonious model that considers all the multitude of potential determinants as creating effectively random noise within the dental biofilm to which the tissues react by accumulating the effects of this noise.

Conclusions

We suggest that such a model can explain many of the epidemiological features of periodontal breakdown over time, and we discuss its clinical implications.

43-Year Temporal Trends in Immune Response to Oral Bacteria in a Swedish Population

Bacteria colonizing the mouth induce an adaptive immune response with the systemic and local presence of species or strain-specific immunoglobulins. Few studies have addressed global antibody patterns for oral bacteria or potential population time trends. We assessed these aspects in relation to a panel of oral bacteria. Using multiplex immunoblotting, IgG levels for 26 oral bacterial species (54 strains) were determined in 888 plasma samples from 30-year-old early pregnant women (n = 516) and 50-year-old men and women (n = 372) collected between 1976 and 2018. Inter-species correlations were found and age-dependent profiles and levels of immune responses to oral bacteria confirmed. We found temporal trends in the global and single-species antibody responses, but this was age-specific with both inclining and declining shifts. Prominent shifts in the younger group increased IgG towards health-associated Streptococcus salivarius and Streptococcus sanguinis, and in the older group towards disease-associated Aggregatibacter actinomycetemcomitans, Filifactor alocis, and Streptococcus mutans, among others. We concluded that temporal shifts occurred from 1976 to 2018, which may reflect improved oral health (more remaining teeth) and altered lifestyle habits, but this needs to be evaluated in observational studies considering more aspects.

Phenytoin sodium-ameliorated gingival fibroblast aging is associated with autophagy

BACKGROUND AND OBJECTIVE

Human gingival fibrolasts aging is an important cause of periodontal disease. Phenytoin sodium (phenytoin) has a side effect of gingival hyperplasia and an effect on the autophagy progress. This study investigated whether the effect of phenytoin on aging gingival fibroblast is related to the autophagy pathway.

MATERIAL AND METHODS

The aging model of gingival fibroblast cell line HGF-1 was induced by hydrogen peroxide (H₂ O₂ ), and the treatment of phenytoin and 3-methyladenine (3-MA) was performed simultaneously. Cell viability, cell cycle, and intracellular calcium ion were measured by flow cytometry. Changes in expression of basic fibroblast growth factor (bFGF), P16^INK4A , P21^cip1 , and bFGF, P16^INK4A , P21^cip1 , LC3II, p62, and Beclin were tested by using reverse transcription polymerase chain reaction, western blot, and immunofluorescence staining.

RESULTS

The results showed that aging HGF-1 proliferation was inhibited by H₂ O₂ , gene, protein expression of bFGF, P16^INK4A , and P21^cip1 were decreased, autophagy-related proteins LC3II, p62, and Becline were decreased, and the proportion of G0/G1 phase and intracellular calcium ion of cell cycle was increased. Phenytoin treatment could recovery above changes, but the effect of phenytoin could be blocked by 3-MA.

CONCLUSION

We propose that phenytoin alleviates the aging of gingival fibroblasts induced by H₂ O₂ . This condition is related to the enhancement of autophagy pathway.

Regulation of Salivary Peptidoglycan Recognition Protein 1 in Adolescents

INTRODUCTION

Peptidoglycan recognition protein 1 (PGLYRP1), a member of peptidoglycan recognition proteins, is known to be involved in the proinflammatory response toward bacterial infections. Recently, PGLYRP1 was identified as a ligand for triggering receptor expressed on myeloid cells 1 (TREM-1). Although PGLYRP1 is involved in immune and inflammatory responses, its levels in initial stages of periodontal disease in adolescents are currently unknown.

OBJECTIVES

We aimed to investigate salivary levels of PGLYRP1 and its correlation with TREM-1, polymorphonuclear leukocyte elastase (PMN elastase), and an active matrix metalloproteinase 8 (aMMP-8) in adolescents.

METHODS

Whole saliva samples (n = 537) were collected from 15- to 16-y-old adolescents at Kotka Health Center, Finland, prior to periodontal examination, including measurement of periodontal pocket depth (PPD), visible plaque index (VPI), and bleeding on probing (BOP). Adolescents, clustered as periodontally healthy, gingivitis, or subclinical periodontitis, were tested for salivary levels of TREM-1, PGLYRP1, and PMN elastase by enzyme-linked immunosorbent assay and aMMP-8 by a time-resolved immunofluorometric assay (IFMA).

RESULTS

Salivary levels of PGLYRP1 and aMMP-8 were significantly higher in adolescents with subclinical periodontitis and gingivitis compared to individuals with healthy periodontium. TREM-1 and PMN elastase levels were higher in adolescents with subclinical periodontitis compared to healthy individuals but did not reach significance. PGLYRP1 correlated positively with BOP, PPD, VPI, aMMP-8, and TREM-1.

CONCLUSIONS

Elevated PGLYRP1 levels in adolescents with gingivitis and subclinical periodontitis and its positive correlation with TREM-1 and aMMP-8 may indicate an association of PGLYRP1 with initial stages of periodontal disease. Sex and poor oral hygiene but not smoking are also associated with higher levels of PGLYRP1. However, PGLYRP1 has a lower discriminating capacity and is therefore a less reliable marker alone in the diagnosis of initial stages of periodontal disease in adolescents.

KNOWLEDGE TRANSFER STATEMENT

PGLYRP1, a member of peptidoglycan recognition proteins, is a ligand for TREM-1. Elevated PGLYRP1 levels in adolescents with gingivitis and subclinical periodontitis and its positive correlation with TREM-1 and aMMP-8 may indicate an association of PGLYRP1 with initial stages of periodontal disease. However, it has a lower discriminating capacity and is therefore a less reliable marker alone in the diagnosis of periodontal disease in adolescents.

IDF Diabetes Atlas: Diabetes and oral health - A two-way relationship of clinical importance

The current scientific evidence for the bi-directional associations between oral health and diabetes is summarized. The universal biologic mechanisms and demographic and behavioral risk drivers underlying these associations in both directions are also described. Dysglycemia, even slightly elevated blood sugar levels, adversely affects oral health, manifesting itself in several oral diseases and conditions. In the opposite direction, any oral infection with its subsequent local and systemic inflammatory responses adversely affects blood glucose levels. Moreover, painful, mobile, or missing teeth may lead to intake of soft food items representing a sub-optimal diet and hence poor nutrition, and thereby contribute to incident type 2 diabetes or to poorer glucose control in existing diabetes. Treatment of inflammation related oral conditions, such as non-surgical periodontal treatment and extraction of infected teeth, can lead to a clinically significant decrease in blood glucose levels. Attention to infectious oral diseases and referral to dental care professionals for treatment can therefore be an important novel tool for medical care professionals in preventing and managing diabetes mellitus. Dental professionals can detect unrecognized potential dysglycemia and refer for medical examination. Such interprofessional, patient centered care may contribute to improved health, wellbeing, and quality of life in people with diabetes.