Microbiologic and immunologic characteristics of periodontal disease in Hispanic americans with type 2 diabetes

Endogenous and microbial biomarkers for periodontitis and type 2 diabetes mellitus

It has been well documented that there is a two-way relationship between diabetes mellitus and periodontitis. Diabetes mellitus represents an established risk factor for chronic periodontitis. Conversely, chronic periodontitis adversely modulates serum glucose levels in diabetic patients. Activated immune and inflammatory responses are noted during diabetes and periodontitis, under the modulation of similar biological mediators. These activated responses result in increased activity of certain immune-inflammatory mediators including adipokines and microRNAs in diabetic patients with periodontal disease. Notably, certain microbes in the oral cavity were identified to be involved in the occurrence of diabetes and periodontitis. In other words, these immune-inflammatory mediators and microbes may potentially serve as biomarkers for risk assessment and therapy selection in diabetes and periodontitis. In this review, we briefly provide an updated overview on different potential biomarkers, providing novel diagnostic and therapeutic insights on periodontal complications and diabetes mellitus.

Patients with type 2 diabetes and severe periodontitis harbor a less pathogenic subgingival biofilm than normoglycemic individuals with severe periodontitis

BACKGROUND

Whether, and to what extent, diabetes mellitus (DM) can affect the subgingival biofilm composition remains controversial. Thus, the aim of this study was to compare the composition of the subgingival microbiota of non-diabetic and type 2 diabetic patients with periodontitis using 40 "biomarker bacterial species."

METHODS

Biofilm samples of shallow (probing depth [PD] and clinical attachment level [CAL] ≤3 mm without bleeding) and deep sites (PD and CAL ≥5 mm with bleeding) of patients with or without type 2 DM were evaluated for levels/proportions of 40 bacterial species by checkerboard DNA-DNA hybridization.

RESULTS

A total of 828 subgingival biofilm samples from 207 patients with periodontitis (118 normoglycemic and 89 with type 2 DM) were analyzed. The levels of most of the bacterial species evaluated were reduced in the diabetic compared with the normoglycemic group, both in shallow and in deep sites. The shallow and deep sites of patients with type 2 DM presented higher proportions of Actinomyces species, purple and green complexes, and lower proportions of red complex pathogens than those of normoglycemic patients (P < 0.05).

CONCLUSIONS

Patients with type 2 DM have a less dysbiotic subgingival microbial profile than normoglycemic patients, including lower levels/proportions of pathogens and higher levels/proportions of host-compatible species. Thus, type 2 diabetic patients seem to require less remarkable changes in biofilm composition than non-diabetic patients to develop the same pattern of periodontitis.

Examining the association between serum IgG of oral bacteria and metabolic syndrome

Aim

This investigation explored the relationship between oral bacteria and metabolic syndrome (METS).

Materials and Methods

There were 4,882 subjects enrolled in this cross-sectional study from the NHANES III database. The severity of periodontitis was classified into mild, moderate and severe. We measured oral bacterial antibodies. We examined the relationship between serum immunoglobulin G (IgG) antibodies of oral bacteria and METS via performing multivariate regression analysis. Mediation analysis of oral bacteria on the correlation between periodontitis and METS was also executed.

Results

After adjusting for covariates, the serum IgG antibodies of P. nigrescens, E. corrodens, and E. nodatum were associated with the presence of METS (p = 0.006, p = 0.014 and p = 0.018, respectively). Furthermore, serum IgG antibodies of P. intermedia, T. forsythia and V. parvula were positively associated with the presence of METS (p = 0.001, p = 0.011, and p = 0.002, respectively) and ≥4 features of METS (p = 0.019, p = 0.025, and p = 0.02, respectively). P. intermedia IgG mediated 11.2% of the relationship between periodontitis and METS.

Conclusion

Serological markers of oral pathogens were correlated with the presence and the number of METS features after multivariable adjustment. Oral bacteria acted as a mediator of the correlation between periodontitis and METS. Our study provided a biologically plausible explanation for the association between periodontitis and METS, which provides a comprehensive evaluation of periodontitis.

Are Inflamed Periodontal Tissues Endogenous Source of Advanced Glycation End-Products (AGEs) in Individuals with and without Diabetes Mellitus? A Systematic Review

Advanced glycation end-products (AGEs) are heterogeneous compounds formed when excess sugars condense with the amino groups of nucleic acids and proteins. Increased AGEs are associated with insulin resistance and poor glycemic control. Recently, inflamed periodontal tissues and certain oral bacteria were observed to increase the local and systemic AGE levels in both normoglycemic and hyperglycemic individuals. Although hyperglycemia induced AGE and its effect on the periodontal tissues is known, periodontitis as an endogenous source of AGE formation is not well explored. Hence, this systematic review is aimed to explore, for the first time, whether inflamed periodontal tissues and periodontal pathogens have the capacity to modulate AGE levels in individuals with or without T2DM and how this affects the glycemic load. Six electronic databases were searched using the following keywords: (Periodontitis OR Periodontal disease OR Periodontal Inflammation) AND (Diabetes mellitus OR Hyperglycemia OR Insulin resistance) AND Advanced glycation end products. The results yielded 1140 articles, of which 13 articles were included for the review. The results showed that the mean AGE levels in gingival crevicular fluid was higher in individuals with diabetes mellitus and periodontitis (521.9 pg/mL) compared to healthy individuals with periodontitis (234.84 pg/mL). The serum AGE levels in normoglycemic subjects having periodontitis was higher compared to those without periodontitis (15.91 ng/mL vs. 6.60 ng/mL). Tannerella forsythia, a common gram-negative anaerobe periodontal pathogen in the oral biofilm, was observed to produce methylglyoxal (precursor of AGE) in the gingival tissues. Increased AGE deposition and activate of AGE receptors was noted in the presence of periodontitis in both normoglycemic and hyperglycemic individuals. Hence, it can be concluded that periodontitis can modulate the local and systemic levels of AGE levels even in absence of hyperglycemia. This explains the bidirectional relationship between periodontitis and development of prediabetes, incident diabetes, poor glycemic control, and insulin resistance.

Subgingival pathogens in chronic periodontitis patients affected by type 2 diabetes mellitus: a retrospective case-control study

Purpose

The aim of this study was to compare the prevalence and bacterial load of 6 main periodontal pathogens between pairs of periodontal patients with and without type 2 diabetes mellitus. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans genotypes were also investigated.

Methods

Twenty patients affected by chronic periodontitis and type 2 diabetes were retrospectively selected and matched to 20 patients without diabetes on the basis of the degree and severity of periodontal disease. Microbiological data of subgingival biofilms were analysed and compared for the examined pathogens: A. actinomycetemcomitans, P. gingivalis, Prevotella intermedia, Treponema denticola, Fusobacterium nucleatum, and Tannerella forsythia.

Results

The pairs were balanced in terms of demographic and clinical parameters, except for bleeding on probing and suppuration. In the microbiological test sites (4 for each patient), the mean probing pocket depth was 6.34±1.63 mm in patients with diabetes and 6.41±1.78 mm in patients without diabetes. No significant difference between pairs in the prevalence of P. gingivalis or the distribution of its genotypes was recorded. Patients with diabetes had a significantly greater amount of total bacterial load, P. gingivalis, T. denticola, T. forsythia, and F. nucleatum (P<0.05). Moreover, patients with diabetes had a higher number of sites with a greater cell count than patients without diabetes. When compared to the total bacterial load, only T. forsythia maintained its relative load in patients with diabetes (P=0.001).

Conclusions

This retrospective matched study supports the hypothesis that microbiological differences exist among periodontal patients with and without diabetes mellitus.

Trial Registration

ClinicalTrials.gov Identifier: NCT03786133

Effects of type 2 diabetes and metformin on salivary microbiota in patients with chronic periodontitis

Diabetes is closely associated with periodontitis, however, the effects of type 2 diabetes and metformin treatment on the salivary microbiota in chronic periodontitis patients are still insufficiently studied. Saliva was collected from ten patients with moderate to severe chronic periodontitis (CP group) and 20 patients with type 2 diabetes mellitus (T2DM) and moderate to severe chronic periodontitis (ten patients were newly diagnosed with diabetes without drug treatment (DM group), and ten patients were treated with metformin (CP-DM-MET group)). Total DNA was extracted. DNA amplicons of the V3-V4 hypervariable regions of the 16S rRNA gene were generated and subjected to high-throughput sequencing. There was no significant difference in the alpha diversity of the salivary microbiota (Observed_Species, Shannon, Simpson, ACE, Chao1 index) among the three groups. The dominant phyla with relative abundances greater than 1% were Firmicutes, Proteobacteria, Bacteroidota, Actinobacteriota, Fusobacteriota, and Spirochaetota, and no significant difference was found among the three groups. Compared with the CP group, the relative abundance of twelve genera was found changed in CP-DM group, for example, Aggregatibacter, Unclassified_f_Neisseriaceae, Parvimonas, Erysipelotrichace_UCG-006, Atopobium, and Endomicrobium et al. Metformin treatment could partly restore the abundance of several genera in CP-DM, such as Acholeplasma and Comamonas. Compared with the CP group, genus Lactobacillus, Parvimonas, Norank_f_norank_o_Absconditabacteriales_SR1, and Acholeplasma changed significantly in CP-DM-MET group. Plaque index (PLI) was positively correlated with Prevotella and Lactobacillus but negatively correlated with Haemophilus, Lautropia, Unclassified_f_Pasteurellaceae, and TM7x. In conclusion, there was a significant difference in the salivary microbiota of patients with chronic periodontitis complicated by T2DM. Treatment with metformin partially alleviated the alteration in salivary microbiota caused by T2DM.

Effects of ibuprofen-loaded TiO₂ nanotube dental implants in alloxan-induced diabetic rabbits

Purpose

Some systemic conditions, especially diabetes mellitus (DM), adversely affect dental implant success. This study aimed to investigate the effects of ibuprofen-loaded TiO₂ nanotube (ILTN) dental implants in alloxan-induced diabetic rabbits.

Methods

Twenty-six New Zealand white rabbits were treated with alloxan monohydrate to induce DM. At 2 weeks following DM induction, 3 types of implants (sandblasted, large-grit, and acid-etched [SLA], ILTN, and machined) were placed into the proximal tibia in the 10 rabbits that survived following DM induction. Each type of implant was fitted randomly in 1 of the holes (round-robin method). The animals were administered alizarin (at 3 weeks) and calcein (at 6 weeks) as fluorescent bone markers, and were sacrificed at 8 weeks for radiographic and histomorphometric analyses.

Results

TiO₂ nanotube arrays of ~70 nm in diameter and ~17 μm in thickness were obtained, and ibuprofen was loaded into the TiO₂ nanotube arrays. A total of 26 rabbits were treated with alloxan monohydrate and only 10 rabbits survived. The 10 surviving rabbits showed a blood glucose level of 300 mg/dL or higher, and the implants were placed in these diabetic rabbits. The implant stability quotient (ISQ) and bone-to-implant contact (BIC) values were significantly higher in the ILTN group (ISQ: 61.8, BIC: 41.3%) and SLA group (ISQ: 62.6, BIC: 46.3%) than in the machined group (ISQ: 53.4, BIC: 20.2%), but the difference in the BIC percentage between the SLA and ILTN groups was not statistically significant (P=0.628). However, the bone area percentage was significantly higher in the ILTN group (78.0%) than in the SLA group (52.1%; P=0.000).

Conclusions

The ILTN dental implants showed better stability (ISQ) and BIC than the machined implants; however, these values were similar to the commercially used SLA implants in the 2-week diabetic rabbit model.

Comparison of the frequency of periodontal pathogenic species of diabetics and non-diabetics and its relation to periodontitis severity, glycemic control and body mass index

Objectives

To investigate common pathogenic bacteria of periodontal diseases (PD) in patients with type 2 diabetes mellitus (T2DM) and its relationship with PD severity, glycemic control and body mass index (BMI).

Material and Methods

This case–control study consisted of 55 patients with T2DM and 55 individuals as control. Samples were collected from periodontal pockets. After DNA extraction, using 16srRNA‐specific primers, the presence of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Prevotella intermedia (Pi), and Fusobacterium nucleatum (Fn) were examined based on polymerase chain reaction method.

Results

Aa frequency was significantly higher in in T2DM group than control. There were no significant differences in the frequencies of Pg, Tf, Pi, and Fn between studied groups. There were no significant differences between frequencies of studied bacteria in different severities of periodontitis in T2DM group. Prevalence of Tf in T2DM patients with moderate periodontitis was significantly higher than non‐diabetics with moderate periodontitis. There was no significant difference between the frequency of bacteria in diabetics with good and poor glycemic control. There was a significant difference between the frequencies of Pg in T2DM individuals with different BMI levels.

Conclusions

A higher frequency of detection of Aa was found in diabetic when compared to non‐diabetics. Glycemic control did not affect the frequency distribution of studied bacteria in T2DM. Pg was identified in higher frequency in overweight T2DM patients.

The role of oral microbiome in respiratory health and diseases

The oral cavity (mouth) has various microbial habitats, including, teeth, gingival sulcus, gingiva, tongue, inner cheek, hard palate, and soft palate. The human oral cavity houses the second most diverse microbiome in the body harboring over 700 bacterial species. The fine-tuned equilibrium of the oral microbiome ecosystem maintains oral health. Oral dysbiosis caused by food habits and poor oral hygiene leads to various oral diseases such as periodontitis, caries, gingivitis, and oral cancer. Recent advances in technology have revealed the correlation between the oral microbiome and systemic diseases such as pulmonary diseases, cardiovascular diseases, rheumatoid arthritis, Alzheimer's disease, and other metabolic diseases. Since the oral cavity directly connects with the upper respiratory tract, the oral microbiome has easier access to the respiratory system compared to other organ systems. Direct aspiration of oral microflora in the respiratory system and oral dysbiosis-induced host immune reaction and inflammation are mainly responsible for various pulmonary complications. Numbers of literature have reported the correlation between oral diseases and pulmonary diseases, suggesting the possible role of the oral microbiome in respiratory diseases such as chronic obstructive pulmonary diseases, pneumonia, lung cancer, etc. This paper reviews the current evidence in establishing a link between the oral microbiome and pulmonary diseases. We also discuss future research directions focusing on the oral microbiome to unravel novel therapeutic approaches that could prevent or treat the various pulmonary complications.

Alteration of salivary microbiome in periodontitis with or without type-2 diabetes mellitus and metformin treatment

We aimed to explore the effects of type-2 diabetes mellitus (T2DM) and hypoglycemic therapy on the salivary microbiome in periodontitis patients and identify the potential salivary micro-biomarker for the early warning of T2DM. Saliva samples were collected from healthy individuals (Health), periodontitis patients (P), T2DM patients, periodontitis patients with T2DM (DAP), and DAP patients treated with Metformin (Met). Samples were determined by16S rRNA gene sequencing. 29 phyla, 322 genera, and 333 species of salivary microbiome were annotated. Compared to the Health group, the P and DAP group showed a significantly higher diversity of saliva microbiota, while the T2DM and Met group had no significant difference in microbial abundance but showed a trend of increasing diversity. Other than well-known periodontitis-inducing pathogens, the proportion of Prevotella copri, Alloprevotella rava, and Ralstonia pickettii, etc. were also significantly increased in periodontitis patients with or without T2DM. After effective glycemic control, the abundance of Prevotella copri, Alloprevotella rava, Ralstonia pickettii, etc. decreased in periodontitis patients with companion T2DM. The accuracies of the classification models in differentiating Health-vs.-P, DAP-vs.-P, and T2DM-vs.-P were 100%, 96.3%, and 98.1%, respectively. Hypoglycemic therapy could reconstruct the saliva microbiota and hence improve the localized conditions of diabetes patients with periodontitis.

Effect of diode laser application as an adjunct to nonsurgical periodontal therapy on the reduction of red complex microorganisms in type 2 diabetics with chronic periodontitis

Bactericidal and detoxification effects of diode laser (DL) have been reported in periodontal treatment. The objective of this study was investigating the additional effect of DL with nonsurgical periodontal treatment on the red complex bacteria in type 2 diabetes mellitus (DM) patients with chronic periodontitis (CP). Sixty type 2 DM patients with chronic periodontitis (CP) were randomly assigned in two parallel groups to receive scaling root planning (SRP, n = 30) or SRP followed by DL periodontal pocket irradiation (SRP + DL, n = 30). Recording of clinical parameters and subgingival plaque sampling were performed at baseline, and post therapy (1 and 3 months after treatment). Amounts of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia were evaluated with quantitative RT-PCR. Significant reductions for numbers of all three bacterial species were observed at 1 and 3 months compared with baseline for both treatments (p < 0.001), but no significant differences were found between two groups regarding bacterial reductions at these follow-up time points. No additional benefit of DL as an adjunct to nonsurgical periodontal therapy was recognized in the reduction of P. gingivalis, T. denticola, and T. forsythia for type 2 DM patients with CP. Further studies are required to clarify the effects of diode laser on the other periodontopathogens.

Effect of high glucose levels and lipopolysaccharides-induced inflammation on osteoblast mineralization over sandblasted/acid-etched titanium surface

BACKGROUND AND PURPOSE

Poorly controlled diabetes mellitus has been related to higher risk of implant treatment complications due to increased susceptibility to infection and delayed wound healing. Lipopolysaccharides (LPS) stimulate cytokine production leading to chronic inflammation and immunological host response that accentuates the destruction of periodontal tissues. This study aimed to evaluate the effect of different glycemic conditions on secretion and mineralization of bone matrix under sterile inflammation induced by LPS on osteoblasts seeded over sandblasted/acid-etched (SLA) titanium surface.

MATERIALS AND METHODS

Osteoblast cell viability was performed to determine the influence of different glucose concentrations (5.5, 8, 12, and 24 mM), which were chosen to reflect normal, postprandial, and high glucose values, similar to those typically seen in Diabetes mellitus under clinical conditions. Cells were seeded on titanium SLA discs (Straumann AG, Waldenburg, Switzerland) and exposed to glucose concentrations and LPS (1μg/mL) in order to test inflammatory response (qPCR) and mineralization (Alizarin Red staining).

RESULTS

Osteoblast viability was severely decreased when exposed to higher glucose levels (≥12 mM) and LPS (P < .05) compared to control. When the osteoblasts were exposed to LPS and glucose at ≥8 mM, the gene transcripts of inflammatory cytokines were ≈2.5-fold upregulated, while ≤8 mM glucose elicited no significant change compared to control without glucose treatment (P > .05). Osteoblasts exposed to LPS produced sparse extracellular matrix mineralization, especially combined with higher glucose values (≥12 mM), together with decreased calcium deposition compared to control (P < .05).

CONCLUSIONS

High glucose levels combined with LPS inflammatory stimulation elicited an adverse effect on the volume and quality of mineralized hard tissue formation on SLA titanium surfaces in vitro. Hence, both normal glucose levels and infection control including low levels of circulating LPS during initial osseointegration period may be required to increase the success rate of dental implants.

Gestational diabetes and the human salivary microbiota: a longitudinal study during pregnancy and postpartum

Background

An aberrant composition of the salivary microbiota has been found in individuals with type 2 diabetes, and in pregnant women salivary microbiota composition has been associated with preeclampsia and pre-term birth. Pregnant women, who develop gestational diabetes (GDM), have a high risk of developing type 2 diabetes after pregnancy. In the present study we assessed whether GDM is linked to variation in the oral microbial community by examining the diversity and composition of the salivary microbiota.

Method

In this observational study the salivary microbiota of pregnant women with GDM (n = 50) and normal glucose regulation (n = 160) in third trimester and 9 months postpartum was assessed by 16S rRNA gene amplicon sequencing of the V1-V3 region. GDM was diagnosed in accordance with the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria. Cross-sectional difference in alpha diversity was assessed using Student’s t-test and longitudinal changes were assessed by mixed linear regression. Cross-sectional and longitudinal difference in beta diversity was assessed by permutational multivariate analyses of variance. Differentially abundant genera and OTUs were identified by negative binomial regression.

Results

In the third trimester, two species-level operational taxonomic units (OTUs), while eight OTUs postpartum were differentially abundant in women with GDM compared with normoglycaemic women. OTU richness, Shannon diversity and Pielou evenness decreased from late pregnancy to 9 months after delivery regardless of glycaemic status.

Conclusion

GDM is associated with a minor aberration of the salivary microbiota during late pregnancy and postpartum. For unknown reasons richness of the salivary microbiota decreased from late pregnancy to postpartum, which might be explained by the physiological changes of the immune system during human pregnancy.

[Potential application of human microbiomes in the diagnosis and treatment of type 2 diabetes mellitus]

Human microbiome refers to the total microorganism genetic information of human body surface and internal, which is closely related to human health and disease. Oral and gut microbiomes are the most diverse microbial communities, which can interact and play a role in the development of the disease, and can reflect the health and disease state in real time. Type 2 diabetes mellitus is a metabolic disorder caused by both genetic and environmental factors. Recent research has shown a link between microbes and diabetes. This article reviewed the latest research on the changes of oral and gut microbiomes in type 2 diabetes mellitus patients, which expects to provide a reference for exploring the development of the disease model for prediction, diagnosis and prognosis of type 2 diabetes mellitus based on human microbiome characteristics.

Frequency of putative periodontal pathogens among type 1 diabetes mellitus: a case-control study

Objective

The aim of the present study is to compare and assess the risk of periodontitis due to the presence of four putative periodontopathic bacteria viz., Eikenella corrodens, Campylobacter rectus, Prevotella intermedia and Prevotella nigrescens. To fulfil the above objective, polymerase Chain reaction using the primers targeting 16S rRNA gene of the bacterial species was performed with the subgingival plaque collected from the permanent first molars of type 1 diabetic children and age matched healthy children.

Results

The prevalence of periodontal pathogens in diabetic and healthy children was 6% and 16% for E. corrodens, 18% and 36% for C. rectus, 2% and 2% for P. intermedia, 4% and 0%, for P. nigrescens respectively. Statistically, significant difference was not observed for the prevalence of all the four periodontal pathogens between type 1 diabetic and healthy children (P = 1.00). The results of the present study thus reveal a negative correlation of type I diabetes to periodontitis in association to Eikenella corrodens, Campylobacter rectus, Prevotella intermedia and Prevotella nigrescens.

Oral Plaque from Type 2 Diabetic Patients Reduces the Clonogenic Capacity of Dental Pulp-Derived Mesenchymal Stem Cells

Type 2 diabetes (T2D) is a major metabolic disease and a key epigenetic risk factor for the development of additional clinical complications. Among them, periodontitis (PD), a severe inflammatory disease ascribable to a dysregulated physiology and composition of the oral microbiota, represents one of the most relevant complications. Periodontitis can impact the structure of the tooth and likely the stem and progenitor cell pool, which actively contributes to the periodontal microenvironment and homeostasis. Modifications of the oral plaque play a key role in the etiopathogenesis of PD caused by T2D. However, to what extent the biology of the progenitor pool is affected has still to be elucidated. In this short report, we aimed to explore the biological effects of oral plaque derived from T2D patients with PD in comparison to non-diabetic patients with PD. Oral plaque samples were isolated from T2D and non-diabetic subjects with PD. Dental pulp stem cells (DPSCs), derived from the premolar tooth, were conditioned for 21 days with oral plaque samples and tested for their clonogenic ability. Cultures were also induced to differentiate towards the osteogenic lineage, and ALP and osteocalcin gene expression levels were evaluated by real-time qPCR. Results have shown that the number of clones generated by DPSCs exposed to T2D oral plaque was significantly lower compared to controls (ctl). The multivariate analysis confirmed that the decreased clonogenesis was significantly correlated only with T2D diagnosis. Moreover, the effect of T2D oral plaque was specific to DPSCs. Indicators of osteogenic differentiation were not significantly affected. This study provides a new biological insight into the effects ascribable to T2D in PD.

Polymorphisms of the vitamin D receptor gene (FOKI, CDX2, and GATA) and susceptibility to chronic periodontitis in diabetic and non-diabetic individuals: A case-control study

AIM

The aim of the present study was to evaluate the distribution of single-nucleotide polymorphisms (SNP) (variants FOKI [rs2228570], CDX2 [rs47908762], and GATA [rs4516035]) in the vitamin D receptor in individuals with type 2 diabetes mellitus and chronic periodontitis (DM2 + CP), CP alone, and healthy individuals, and to investigate the relationship with susceptibility to CP.

METHODS

In total, 280 individuals (116 with DM2 + CP, 95 with CP alone, and 69 healthy individuals) were genotyped using real-time polymerase chain reaction with allele-specific probes. Significant differences (P < .05) were found among the groups with regard to socio-epidemiological variables (sex, marital status, income, smoking habit, and schooling) and clinical-epidemiological variables (age, number of teeth, probing depth, clinical attachment loss, gingival bleeding index, and visible plaque index).

RESULTS

The C allele was significantly more frequent among the healthy individuals (34.8%) than those with DM2 + CP (23.5%) (odds ratio [OR] = .58, 95% confidence interval [CI]: . 35-.94, P = .022). Likewise, the CC allele was significantly more frequent among healthy individuals (11.6%) than those with DM2 + CP (2.6%) (OR = .17, 95% CI: .03-.79, P = .015).

CONCLUSION

The results suggest that the presence of these variants could lead to a lower susceptibility to DM2 and CP. No other significant differences among groups were found for the other SNP investigated.

Differences in the subgingival microbial population of chronic periodontitis in subjects with and without type 2 diabetes mellitus-a systematic review

OBJECTIVES

The purpose of this systematic review was to evaluate the available evidence in the literature in regard to the subgingival microbial population of chronic periodontitis in subjects with type 2 diabetes mellitus (T2DM+PD) compared to non-diabetic subjects (NDM+PD).

MATERIALS AND METHODS

A literature search was conducted at Ovid MEDLINE and EMBASE database from 1980 to 2016, supplemented by hand searching as needed. Studies presenting with at least one of the primary outcomes (presence of any subgingival microorganisms, proportion and/or the amount of any subgingival plaque bacteria in T2DM+PD versus NDM+PD) were included. Screening, data extraction and quality assessment were conducted independently and in duplicate.

RESULTS

From 611 citations, 19 full-text papers were screened and 11 articles were included for critical appraisal by both reviewers. Some evidence of a difference in the microbial profile between chronic PD subjects with and without T2DM was identified. The strength of evidence is strongest in Tannerella forthysia (T .forsythia) which was reported to be less frequent in the diabetic (T2DM+PD) group in five of the studies, followed by a weaker strength of evidence for other periodontal pathogens such as Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), which were also found less frequent in the diabetic (T2DM+PD) group .

CONCLUSION

Only few studies have compared T2DM+PD with NDM+PD. It is therefore strongly recommended that further studies which include four distinct groups of participants (NDM+PD, T2DM+PD, NDM+NPD, T2DM+NPD) instead of using intra-subject comparisons between healthy and diseased sites of the same subjects.

CLINICAL RELEVANCE

Differences in bacterial populations of T2DM+PD in comparison to NDM+PD subjects may indicate the need of different protocols for the treatment of the diabetic patients with periodontal disease.

Flagellin Glycoproteomics of the Periodontitis Associated Pathogen Selenomonas sputigena Reveals Previously Not Described O-glycans and Rhamnose Fragment Rearrangement Occurring on the Glycopeptides

Flagellated, Gram-negative, anaerobic, crescent-shaped Selenomonas species are colonizers of the digestive system, where they act at the interface between health and disease. Selenomonas sputigena is also considered a potential human periodontal pathogen, but information on its virulence factors and underlying pathogenicity mechanisms is scarce. Here we provide the first report of a Selenomonas glycoprotein, showing that S. sputigena produces a diversely and heavily O-glycosylated flagellin C9LY14 as a major cellular protein, which carries various hitherto undescribed rhamnose- and N-acetylglucosamine linked O-glycans in the range from mono- to hexasaccharides. A comprehensive glycomic and glycoproteomic assessment revealed extensive glycan macro- and microheterogeneity identified from 22 unique glycopeptide species. From the multiple sites of glycosylation, five were unambiguously identified on the 437-amino acid C9LY14 protein (Thr149, Ser182, Thr199, Thr259, and Ser334), the only flagellin protein identified. The O-glycans additionally showed modifications by methylation and putative acetylation. Some O-glycans carried hitherto undescribed residues/modifications as determined by their respective m/z values, reflecting the high diversity of native S. sputigena flagellin. We also found that monosaccharide rearrangement occurred during collision-induced dissociation (CID) of protonated glycopeptide ions. This effect resulted in pseudo Y1-glycopeptide fragment ions that indicated the presence of additional glycosylation sites on a single glycopeptide. CID oxonium ions and electron transfer dissociation, however, confirmed that just a single site was glycosylated, showing that glycan-to-peptide rearrangement can occur on glycopeptides and that this effect is influenced by the molecular nature of the glycan moiety. This effect was most pronounced with disaccharides. This study is the first report on O-linked flagellin glycosylation in a Selenomonas species, revealing that C9LY14 is one of the most heavily glycosylated flagellins described to date. This study contributes to our understanding of the largely under-investigated surface properties of oral bacteria. The data have been deposited to the ProteomeXchange with identifier PXD005859.

The combined and individual impact of diabetes and smoking on key subgingival periodontal pathogens in patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

Comprehension of the similarities and differences in the composition of the subgingival microbiota of patients with diabetes mellitus (DM), smokers or smokers with DM is an important step in developing therapies specific for these groups at risk for periodontitis. Therefore, the aim of this study was to compare the combined and individual effects of DM and smoking on the levels and prevalence of key subgingival periodontal pathogens in patients with chronic periodontitis.

MATERIAL AND METHODS

One hundred patients with generalized chronic periodontitis were allocated into one of the following groups: DM (n = 25, non-smokers with type 2 DM); S (n = 25, non-diabetic smokers); SDM (n = 25, smokers with type 2 DM); and control (n = 25, non-diabetic non-smokers). Two subgingival biofilm samples from healthy sites (probing depth and clinical attachment level ≤3 mm and no bleeding) and 2 from diseased sites (probing depth and clinical attachment level ≥5 mm and bleeding on probing) were analyzed by quantitative polymerase chain reaction for Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Parvimonas micra, Fusobacterium nucleatum ssp. and Prevotella intermedia.

RESULTS

There were no differences among groups in the mean counts of the bacterial species studied, considering all sampled sites (healthy plus diseased sites). There were also no differences among groups regarding the prevalence of any bacteria species in healthy and diseased sites (P > .05). The mean P. micra count was significantly higher in the healthy sites of both smoking groups, than in those of the control group (P < .05).

CONCLUSION

The subgingival levels and prevalence of the bacterial species studied are not significantly different in subjects with chronic periodontitis presenting DM, smokers or smokers with DM. In addition, DM and smoking, jointly and individually, do not considerably affect the subgingival levels of target periodontal pathogens in patients with chronic periodontitis.

A tale of two risks: smoking, diabetes and the subgingival microbiome

Although smoking and diabetes have been established as the only two risk factors for periodontitis, their individual and synergistic impacts on the periodontal microbiome are not well studied. The present investigation analyzed 2.7 million 16S sequences from 175 non-smoking normoglycemic individuals (controls), smokers, diabetics and diabetic smokers with periodontitis as well as periodontally healthy controls, smokers and diabetics to assess subgingival bacterial biodiversity and co-occurrence patterns. The microbial signatures of periodontally healthy smokers, but not diabetics, were highly aligned with the disease-associated microbiomes of their respective cohorts. Diabetics were dominated by species belonging to Fusobacterium, Parvimonas, Peptostreptococcus, Gemella, Streptococcus, Leptotrichia, Filifactor, Veillonella, TM7 and Terrahemophilus. These microbiomes exhibited significant clustering based on HbA1c levels (pre-diabetic (<6.5%), diabetic (6.5–9.9%), diabetics >10%). Smokers with periodontitis evidenced a robust core microbiome (species identified in at least 80% of individuals) dominated by anaerobes, with inter-individual differences attributable largely to the ‘rare biosphere’. Diabetics and diabetic smokers, on the other hand, were microbially heterogeneous and enriched for facultative species. In smokers, microbial co-occurrence networks were sparse and predominantly congeneric, while robust inter-generic networks were observed in diabetics and diabetic smokers. Smoking and hyperglycemia impact the subgingival microbiome in distinct ways, and when these perturbations intersect, their synergistic effect is greater than what would be expected from the sum of each effect separately. Thus, this study underscores the importance of early intervention strategies in maintaining health-compatible microbiomes in high-risk individuals, as well as the need to personalize these interventions based on the environmental perturbation.

Influence of glycemic control on the levels of subgingival periodontal pathogens in patients with generalized chronic periodontitis and type 2 diabetes

Objective

This study evaluated the influence of glycemic control on the levels and frequency of subgingival periodontal pathogens in patients with type 2 diabetes mellitus (DM) and generalized chronic periodontitis (ChP).

Material and Methods

Fifty-six patients with generalized ChP and type 2 DM were assigned according to the levels of glycated hemoglobin (HbA1c) into one of the following groups: HbA1c<8% (n=28) or HbA1c≥8% (n=28). Three subgingival biofilm samples from sites with probing depth (PD)<5 mm and three samples from sites with PD≥5 mm were analyzed by quantitative Polymerase Chain Reaction (PCR) for the presence and levels of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Parvimona micra, Fusobacterium nucleatum ssp. and Prevotella intermedia.

Results

The mean counts of F. nucleatum ssp. were statistically significantly higher in the sites with PD≥5 mm of the HbA1c≥8% group (p<0.05). Frequencies of detection of T. forsythia, E. nodatum, P. micra and F. nucleatum ssp. were all higher in the sites with PD≥5 mm of the patients with HbA1c≥8%, compared with those of patients with HbA1c<8% (p<0.05). Frequency of detection of P. intermedia was higher in the sites with PD<5 mm of the patients with HbA1c≥8% than those of the patients with HbA1c<8% (p<0.05).

Conclusions

Poor glycemic control, as indicated by HbA1c≥8%, is associated with increased levels and frequencies of periodontal pathogens in the subgingival biofilm of subjects with type 2 DM and ChP.

Effects of glucose concentration on osteogenic differentiation of type II diabetes mellitus rat bone marrow-derived mesenchymal stromal cells on a nano-scale modified titanium

BACKGROUND AND OBJECTIVE

Diabetes mellitus (DM) is a common disease worldwide. Patients with DM have an increased risk of losing their teeth compared with other individuals. Dental implants are a standard of care for treating partial or full edentulism, and various implant surface treatments have recently been developed to increase dental implant stability. However, some studies have reported that DM reduces osseointegration and the success rate of dental implants. The purpose of this study was to determine the effects of high glucose levels for hard tissue formation on a nano-scale modified titanium surface.

MATERIAL AND METHODS

Titanium disks were heated at 600°C for 1 h after treatment with or without 10 m NaOH solution. All disks were incubated with type II DM rat bone marrow-derived mesenchymal stromal cells before exposure to one of four concentrations of glucose (5.5, 8.0, 12.0 or 24.0 mm). The effect of different glucose concentrations on bone marrow-derived mesenchymal stromal cell osteogenesis and inflammatory cytokines on the nano-scale modified titanium surface was evaluated.

RESULTS

Alkaline phosphatase activity decreased with increasing glucose concentration. In contrast, osteocalcin production and calcium deposition were significantly decreased at 8.0 mm glucose, but increased with glucose concentrations over 8.0 mm. Differences in calcium/phosphate ratio associated with the various glucose concentrations were similar to osteocalcin production and calcium deposition. Inflammatory cytokines were expressed at high glucose concentrations, but the nano-scale modified titanium surface inhibited the effect of high glucose concentrations.

CONCLUSION

High glucose concentration increased hard tissue formation, but the quality of the mineralized tissue decreased. Furthermore, the nano-scale modified titanium surface increased mineralized tissue formation and anti-inflammation, but the quality of hard tissue was dependent on glucose concentration.

Integrated biomarker profiling of smokers with periodontitis

BACKGROUND

In the context of precision medicine, understanding patient-specific variation is an important step in developing targeted and patient-tailored treatment regimens for periodontitis. While several studies have successfully demonstrated the usefulness of molecular expression profiling in conjunction with single classifier systems in discerning distinct disease groups, the majority of these studies do not provide sufficient insights into potential variations within the disease groups.

AIM

The goal of this study was to discern biological response profiles of periodontitis and non-periodontitis smoking subjects using an informed panel of biomarkers across multiple scales (salivary, oral microbiome, pathogens and other markers).

MATERIAL & METHODS

The investigation uses a novel ensemble classification approach (SVA-SVM) to differentiate disease groups and patient-specific biological variation of systemic inflammatory mediators and IgG antibody to oral commensal and pathogenic bacteria within the groups.

RESULTS

Sensitivity of SVA-SVM is shown to be considerably higher than several traditional independent classifier systems. Patient-specific networks generated from SVA-SVM are also shown to reveal crosstalk between biomarkers in discerning the disease groups. High-confidence classifiers in these network abstractions comprised of host responses to microbial infection elucidated their critical role in discerning the disease groups.

CONCLUSIONS

Host adaptive immune responses to the oral colonization/infection contribute significantly to creating the profiles specific for periodontitis patients with potential to assist in defining patient-specific risk profiles and tailored interventions.

Cross-Sectional Analysis of Alcohol Intake and Serum Antibodies to Oral Microorganisms

The objective of this study was to evaluate the relation between alcohol intake and groups of periodontal antibody titers among individuals with normal glucose tolerance (NGT), prediabetes and diabetes. This was a cross-sectional analysis of the National Health and Nutrition Examination Survey III (NHANES III) 1988–1994 data, among individuals 40 y and older with information on alcohol intake and serum immunoglobulin G (IgG) antibody data against 19 oral microorganisms. Participants were excluded if they did not have teeth, reported that they were taking insulin, or having gestational diabetes. The sample size for this analysis was 3,219. Periodontal antibodies were grouped into four clusters using cluster analysis: Orange-Red, Red-Green, Yellow- Orange, and Orange-Blue. Cluster scores were computed for each individual by summing z-scores of standardized log-transformed IgG titers of antibodies against periodontal microorganisms making up each respective cluster. Each cluster score was modeled as an outcome. Alcohol consumption was assessed in g/day using self-reported number of days of drinking in the past 12 mo and the average number of drinks consumed per day on days when they drank. Overall, alcohol intake was positively associated with periodontal antibodies of the Orange-Red cluster (P. melaninogenica, P. intermedia, P. nigrescens, and P. gingivalis), and inversely associated with the Yellow-Orange cluster (S. intermedius, S. oralis, S. mutans, F. nucleatum, P. micra, C. ochracea) after multivariable adjustment. The association between alcohol intake and the Orange-Red cluster was strongest among individuals with diabetes; this relation was seen among individuals with and without periodontal damage. The Orange-Red cluster was positively associated with periodontal damage among individuals with diabetes. Alcohol intake was not associated with any antibody cluster among individuals with NGT or prediabetes. The effect of alcohol intake on periodontal disease may be greater among individuals with diabetes but this finding needs to be confirmed in prospective studies.

Knowledge Transfer Statement: The results of this study can be used by clinicians when treating patients with periodontal disease and diabetes.

The Oral Microbiome in Health and Its Implication in Oral and Systemic Diseases

The oral microbiome can alter the balance between health and disease, locally and systemically. Within the oral cavity, bacteria, archaea, fungi, protozoa, and viruses may all be found, each having a particular role, but strongly interacting with each other and with the host, in sickness or in health. A description on how colonization occurs and how the oral microbiome dynamically evolves throughout the host's life is given. In this chapter the authors also address oral and nonoral conditions in which oral microorganisms may play a role in the etiology and progression, presenting the up-to-date knowledge on oral dysbiosis as well as the known underlying pathophysiologic mechanisms involving oral microorganisms in each condition. In oral pathology, oral microorganisms are associated with several diseases, namely dental caries, periodontal diseases, endodontic infections, and also oral cancer. In systemic diseases, nonoral infections, adverse pregnancy outcomes, cardiovascular diseases, and diabetes are among the most prevalent pathologies linked with oral cavity microorganisms. The knowledge on how colonization occurs, how oral microbiome coevolves with the host, and how oral microorganisms interact with each other may be a key factor to understand diseases etiology and progression.

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

BACKGROUND AND OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Dental Implant Sites in Healthy versus Diabetic Subjects: A Two-Year Clinical and Bacteriological Assessment

The aim of this study was to analyze by Real-Time Polymerase Chain Reaction (PCR) possible differences in periimplant microbiota of patients without significant systemic diseases versus patients affected by non-insulin-dependent diabetes mellitus (NIDDM), both treated with dental implants with the same implant-abutment system. Patients suffering from NIDDM, and those with no history of major systemic diseases, treated with dental implants at the Prosthodontics Operative Unit of “Sapienza” University of Rome in the period February 2009 - March 2010 were considered. Clinical parameters as well as microbiological profile were evaluated for each implant site at 3, 6,12, and 24 month follow-up. Crevicular fluid was collected for microbial sampling and analyzed by Real-Time PCR in order to identify the possible presence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum and Prevotella intermedia. Eight patients suffering from NIDDM and 22 with no history of major systemic diseases were included in the present investigation, each having received one to three dental implants. All the implants had been loaded 3 months after surgery, and the average follow-up after implant placement was 26.37±3.86. Clinical parameters showed no noticeable difference between the two groups, except for the Implant Stability Quotient (ISQ) that showed significantly lower values in NIDDM patients. A slightly higher amount of the considered pathogenic bacteria were retrieved in samples collected from patients with NIDDM (7.38×105) in comparison with those of healthy subjects (6.78×105), though the differences were below statistical significance. Within the limitations of the present study, a slight correlation was empirically detected between gene expression profiles of microbial populations and history of NIDDM, which however remained below the statistical significance. Further well-designed clinical studies may be useful to conclusively clarify the impact of subgingival microflora on the increased susceptibility of diabetic patients to periimplantitis.

A review of the evidence for pathogenic mechanisms that may link periodontitis and diabetes

AIMS

To review the evidence for the molecular and cellular processes that may potentially link periodontal disease and diabetes. The pathogenic roles of cytokines and metabolic molecules (e.g. glucose, lipids) are explored and the role of periodontal bacteria is also addressed. Paradigms for bidirectional relationships between periodontitis and diabetes are discussed and opportunities for elaborating these models are considered.

METHODS

Database searches were performed using MeSH terms, keywords, and title words. Studies were evaluated and summarized in a narrative review.

RESULTS

Periodontal microbiota appears unaltered by diabetes and there is little evidence that it may influence glycaemic control. Small-scale clinical studies and experiments in animal models suggest that IL-1β, TNF-α, IL-6, OPG and RANKL may mediate periodontitis in diabetes. The AGE-RAGE axis is likely an important pathway of tissue destruction and impaired repair in diabetes-associated periodontitis. A role for locally activated pro-inflammatory factors in the periodontium, which subsequently impact on diabetes, remains speculative.

CONCLUSION

There is substantial information on potential mechanistic pathways which support a close association between diabetes and periodontitis, but there is a real need for longitudinal clinical studies using larger patient groups, integrated with studies of animal models and cells/tissues in vitro.

Effect of oral hygiene maintenance on HbA1c levels and peri-implant parameters around immediately-loaded dental implants placed in type-2 diabetic patients: 2 years follow-up

OBJECTIVE

The aim of the present 2-year follow-up study was to assess the effect of oral hygiene maintenance on hemoglobin Alc (HbA1c) levels and peri-implant parameters around immediately-loaded dental implants placed in type-2 diabetic patients with varying glycemic levels.

MATERIAL AND METHODS

Ninety-one individuals were divided into three groups. In group 1, 30 systemically healthy individuals were included (HbA1c < 6%). Patients in group 2 and 3, comprised of 30 patients with T2DM (HbA1c 6.1-8%); and 31 patients with T2DM (HbA1c 8.1-10%) respectively. In all groups, patients received immediately loaded bone level implants. All participants were enrolled in a 6 monthly periodontal/peri-implant maintenance program. Peri-implant bleeding on probing (BOP), probing depth (PD), and marginal bone loss (MBL) were measured at 6, 12, and 24 months of follow-up.

RESULTS

Mean preoperative HbA1c levels in patients in groups 1, 2, and 3 were 4.5%, 6.8%, and 8.7% respectively. In group-1, there was no significant difference in HbA1c levels at all follow-up durations. Among patients in groups 2 and 3, there was a significant decrease in HbA1c levels at 24-months follow-up than 6-months follow-up. At 6 months follow-up, BOP, PD, and MBL were significantly higher among patients in group-3 than group-1. At 12 and 24 months follow-up, there was no significant difference in BOP, PD, and MBL in all groups.

CONCLUSIONS

Oral hygiene maintenance reduces hyperglycemia and peri-implant inflammatory parameters around immediately loaded dental implants placed in type 2 diabetic patients.

Quantification of Porphyromonas gingivalis in chronic periodontitis patients associated with diabetes mellitus using real-time polymerase chain reaction

Introduction:

Periodontal diseases, if left untreated, can lead to tooth loss and affect at least one tooth in 80% of adults worldwide, with the main cause being a bacterial plaque. Among subgingival plaque bacterial species, Porphyromonas gingivalis has been implicated as a major etiological agent causing tooth loss. Diabetics and smokers are two patient groups at high risk for periodontal disease. The increase in the number of this organism with the coexistence of other pathogenic microbes leads to rapid destruction of the periodontium, premature loss of teeth and also because of its virulence has implications in systemic pathology. Our aim was to observe the involvement of P. gingivalis in diabetes mellitus (DM) patients associated with periodontitis with and without tobacco-associated habits and to compare them with periodontitis patients having no other systemic pathologies.

Materials and Methods:

Subgingival plaque samples from a total of seventy subjects were included in the study. DNA was isolated from the collected sample and was quantified using spectrophotometer for standardizing the polymerase chain reaction. The quantity of the isolated DNA was checked in a ultraviolet-visible spectrophotomer.

Statistics:

One-way ANOVA and Tukey's multiple post hoc procedures were carried out.

Results:

The maximum score of P. gingivalis was seen in periodontitis patients having DM, whereas the least score was seen in periodontitis patients having DM with tobacco smoking habit compared to the other groups.

Conclusion:

P. gingivalis count is significantly reduced in periodontitis patients having DM with smoking habit; it is concluded that P. gingivalis might not be a key causative organism responsible for the periodontal destruction in case of smokers despite the DM condition. The decrease in counts may be attributed to change in the local environment like chemical (tobacco nitrosamines) and physical changes preventing the growth of P. gingivalis.

Green Tea Modulates Cytokine Expression in the Periodontium and Attenuates Alveolar Bone Resorption in Type 1 Diabetic Rats

Diabetes mellitus comprises a heterogeneous group of disorders with the main feature of hyperglycemia. Chronic hyperglycemia increases the severity of periodontal disease via an exacerbated inflammatory response, activated by advanced glycation end products and their receptor, RAGE. Therefore, anti-inflammatory agents represent potential inhibitors of this pathological interaction. In particular, green tea has been shown to possess anti-inflammatory properties mediated by its polyphenol content.

OBJECTIVES

This study investigated the mechanisms by which green tea attenuates the spontaneous onset of diabetes-induced periodontitis.

METHODS

Diabetes was induced in rats via a single intraperitoneal injection of streptozotocin (STZ). Diabetic and control animals were divided into water-treated and green tea-treated subgroups and were analyzed at 15, 30, 60 and 90 days after diabetes induction. Immunohistochemistry was performed to quantitatively evaluate tumor necrosis factor-α (TNF-α), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), interleukin-10 (IL-10) and runt-related transcription factor 2 (RUNX-2) expression in serial sections of each hemimaxilla. Morphometric measurements of the distance from the cementum-enamel junction (CEJ) of the superior distal root of the first molar to the alveolar bone crest (ABC) were performed to assess bone loss.

RESULTS

Diabetes resulted in significant bone loss and alterations in the number of cells that stained positive for inflammatory mediators. In the diabetic rats treated with green tea, we observed a decreased number of cells expressing RANKL and TNF-α compared with that observed in the diabetic rats treated with water. Additionally, green tea increased the numbers of cells that stained positive for OPG, RUNX-2 and IL-10 in the diabetic rats.

CONCLUSION

Green tea intake reduces expression of the pro-inflammatory cytokine TNF-α and the osteoclastogenic mediator RANKL to normal levels while increasing expression of the anti-inflammatory cytokine IL-10, the osteogenesis-related factor RUNX-2 and the anti-osteoclastogenic factor OPG. Therefore, green tea represents a potential therapeutic agent for the treatment of diabetes-related periodontal disease.

Association between polycystic ovary syndrome, oral microbiota and systemic antibody responses

Polycystic ovary syndrome (PCOS) is a hormonal disorder of women that not only is the leading cause of infertility but also shows a reciprocal link with oral health. This study aimed to investigate the hypothesis that the levels of putative periodontal pathogens in saliva and their antibody response in serum are elevated in PCOS, compared to systemic health. A total of 125 women were included in four groups; 45 women with PCOS and healthy periodontium, 35 women with PCOS and gingivitis, 25 systemically and periodontally healthy women, 20 systemically healthy women with gingivitis. Salivary levels of seven putative periodontal pathogens were analyzed by quantitative real-time polymerase chain reaction and serum antibody levels were analyzed by ELISA. In women with PCOS, salivary Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus oralis and Tannerella forsythia levels were higher than matched systemically healthy women, particularly in the case of gingivitis. Aggregatibacter actinomycetemcomitans and Treponema denticola levels were similar among study groups. The presence of PCOS also enhanced P. gingivalis, Prevotella intermedia and S. oralis serum antibody levels, when gingivitis was also present. Gingival inflammation correlated positively with levels of the studied taxa in saliva, particularly in PCOS. The presence of P. gingivalis and F. nucleatum in saliva also exhibited a strong positive correlation with the corresponding serum antibody levels. In conclusion, as an underlying systemic endocrine condition, PCOS may quantitatively affect the composition of oral microbiota and the raised systemic response to selective members of this microbial community, exerting a confounding role in resultant gingival inflammation and periodontal health. The most consistent effect appeared to be exerted on P. gingivalis.

The oral microbiome diversity and its relation to human diseases

As one of the most clinically relevant human habitats, the human mouth is colonized by a set of microorganisms, including bacteria, archaea, fungi, and viruses. Increasing evidence has supported that these microbiota contribute to the two commonest oral diseases of man (dental caries and periodontal diseases), presenting significant risk factors to human health conditions, such as tumor, diabetes mellitus, cardiovascular diseases, bacteremia, preterm birth, and low birth weight in infants. It is widely accepted that oral microorganisms cause diseases mainly by a synergistic or cooperative way, and the interspecies interactions within the oral community play a crucial role in determining whether oral microbiota elicit diseases or not. Since a comprehensive understanding of the complex interspecies interactions within a community needs the knowledge of its endogenous residents, a plenty of research have been carried out to explore the oral microbial diversity. In this review, we focus on the recent progress in this field, including the oral microbiome composition and its association with human diseases.

Effect of nonsurgical periodontal treatment on glycosylated hemoglobin in diabetic patients: a systematic review

This review was designed to determine whether non-surgical periodontal treatment is able to reduce serum glycosylated hemoglobin (HbA1c) levels in patients with diabetes mellitus (DM). Several previous reports showed that scaling and root planning (SRP) improve periodontal status in patients with DM, but whether it also improves metabolic control of the disease is unclear. A systematic review was conducted according to the recommendations of the Cochrane Collaboration and PRISMA. A literature search was conducted in October 2012 using three libraries (Cochrane, Web of Knowledge, and Scopus) and the keywords "periodontal disease" and "diabetes mellitus." Only 21 of the articles met the inclusion criteria for this review. A total of 1,454 patients were thus included in this study to evaluate whether periodontal treatment improved serum HbA1c levels. Both the methodological quality and the risk of bias of each study were taken into account using the Jadad scale. Only ten of the included studies had an acceptable-good score of 3-5. Fourteen of the studies reported a significant decrease in serum HbA1c levels (p < 0.05) after periodontal treatment. The remaining seven studies failed to find a significant decrease in serum HbA1c. The findings of this review suggest that the published literature is insufficient and inconclusive to clearly support periodontal treatment as a means to improve serum HbA1c levels in patients with type 1 DM. It also demonstrates the need for homogeneous studies, with larger samples and longer follow-up periods, to properly address this question.

Association between Serum Antibodies to Oral Microorganisms and Hyperglycemia in Adults

We conducted a cross-sectional analysis to evaluate the relationship between serum antibody titers against 19 selected oral microorganisms and measures of hyperglycemia in a large, nationally representative data set. The study population consisted of 7,848 participants from the National Health and Nutrition Examination Survey III (1988-1994) who were at least 40 yrs old, with complete serum IgG antibody data against 19 oral microorganisms. The 19 antibody titers were grouped into 4 categories via cluster analysis--orange-red, yellow-orange, orange-blue, and red-green--named to reflect predominant antibody titers against microorganisms in Socransky's classification scheme for oral microbes. Linear regression models weighted for complex survey design were used in which fasting blood glucose, fasting insulin, and HbA1c were outcomes and antibody cluster scores were exposures, adjusting for potential confounders. Higher orange-red cluster scores were associated with increased hyperglycemia, while higher orange-blue cluster scores were related with decreased hyperglycemia. A 1-unit-higher orange-red cluster score was associated with 0.46 mg/dL higher fasting blood glucose (p = .0038), and a 1-unit-higher orange-blue cluster score was associated with 0.34% lower HbA1c (p = .0257). Groups of antibody titers against periodontal microorganisms were associated with hyperglycemia independent of known risk factors.

Microbiological changes after periodontal therapy in diabetic patients with inadequate metabolic control

The present study investigated the effect of non-surgical periodontal treatment (SRP) on the composition of the subgingival microbiota of chronic periodontitis (CP) in individuals with type 2 diabetes (DM2) with inadequate metabolic control and in systemically healthy (SH) individuals. Forty individuals (20 DM2 and 20 SH) with CP underwent full-mouth periodontal examination. Subgingival plaque was sampled from 4 deep sites of each individual and tested for mean prevalence and counts of 45 bacterial taxa by the checkerboard method. Clinical and microbiological assessments were performed before and 3 months after SRP. At baseline, those in the DM2 group presented a significantly higher percentage of sites with visible plaque and bleeding on probing compared with those in the SH group (p<0.01). Those in the DM2 group presented significantly higher levels of C. rectus and P. gingivalis, and lower prevalence of P. micra and S. anginosus, compared with those in the SH group (p≤0.001). At the 3-month visit, both groups showed a significant improvement in all clinical parameters (p<0.01). Those in the DM2 group showed significantly higher prevalence and/or levels of A. gerencseriae, A. naeslundii I, A. oris, A. odontolyticus, C. sputigena, F. periodonticum, and G. morbillorum compared with those in the SH group (p≤0.001). However, those in the DM2 group showed a significant reduction in the levels of P. intermedia, P. gingivalis, T. forsythia, and T. denticola (p≤0.001) over time. Those in the SRP group showed improved periodontal status and reduced levels of putative periodontal pathogens at 3 months' evaluation compared with those in the DM2 group with inadequate metabolic control.

Relationship between Type 2 Diabetic Retinopathy and Periodontal Disease in Iranian Adults

Background:

Periodontal disease in diabetic patients can compromise a patient's ability to maintain a proper metabolic control and may be associated with diabetic complication.

Aims:

This study was designed to evaluate the frequency of periodontal disease in patients with type 2 diabetes mellitus (DM) and how this was related with the presence of diabetic retinopathy (DR).

Materials and Methods:

A comparison was made of periodontal parameters (plaque index (PI), community periodontal index of treatment needs (CPITN), periodontal disease severity measured in quartiles of probing depth (PD), and clinical attachment loss (CAL)) in a group of diabetic patients with retinopathy (n = 84) versus a group of diabetic patients without retinopathy (n = 129). In addition, 73 age- and sex-matched individuals were selected to serve as the control group. Analysis was performed to evaluate the relationships between periodontal disease and DR.

Results:

In terms of PI, no statistically significant differences were observed, so, oral hygiene was similar in both groups. Diabetic patients with retinopathy had greater CPITN (P < 0.001) and more severe periodontal disease (P < 0.001) than no retinopathy. Also, our results indicated a relationship between type 2 DM and periodontal disease.

Conclusions:

The patients with diabetes retinopathy appear to show increased periodontal disease susceptibility.

A bidirectional relationship of oral-systemic responses: observations of systemic host responses in patients after full-mouth extractions

OBJECTIVE

This investigation tested the hypothesis that systemic inflammatory responses would be attenuated by minimizing the oral microbial burden in patients with moderate to severe periodontitis.

STUDY DESIGN

Patients (n = 73) scheduled for full-mouth extractions were categorized as case type I/II (gingivitis/mild periodontitis) or case type III/IV (moderate/severe periodontitis). Serum levels of acute phase proteins (APPs) and immunoglobulin G (IgG) antibody were assessed at baseline and through 1 year after extraction.

RESULTS

At baseline, the levels of multiple APPs (e.g., fibrinogen, C-reactive protein) and antibodies to periodontal pathogens were significantly higher with case type III/IV vs I/II. These differences were sustained 12 months after extractions for most APPs.

CONCLUSIONS

The results demonstrated that removal of disease by full-mouth extraction of teeth altered the overall burden of challenge to the host. Continued elevation in various APPs in the III/IV group suggested a potential underlying constitutive difference in systemic response characteristics of this population.

Periodontitis: oral complication of diabetes

Periodontitis is a common, chronic, inflammatory disease in which the supporting apparatus of the teeth is gradually destroyed, resulting in tooth mobility and tooth loss. Susceptibility to periodontitis is increased approximately three-fold in people with diabetes. Hyperglycemia leads to exacerbated tissue destruction and the clinical signs of periodontitis. There is evidence to support a two-way relationship between periodontitis and diabetes; not only does diabetes increase the risk for periodontitis, but periodontitis is associated with compromised glycemic control. Cooperation between health care teams would benefit the treatment of patients with diabetes and periodontitis.

Smoking-related cotinine levels and host responses in chronic periodontitis

BACKGROUND AND OBJECTIVE

Smoking has been reported to increase the risk of periodontal disease by disrupting the balance of immune responses and tissue repair processes; however, this risk varies among smokers. Cotinine levels in saliva are routinely used to measure the level of smoking, and reflect the quantity of nicotine, and other smoking-related xenobiotics that challenge host systems. This study delineated characteristics of inflammatory mediators in saliva and serum antibody responses to both periodontal pathogens and commensal bacteria in smokers as they related to cotinine levels.

MATERIALS AND METHODS

This case-control study (n = 279) examined salivary inflammatory mediator responses [interleukin (IL)-1ß, IL-10, prostaglandin E2, myeloperoxidase and plasminogen activator inhibitor-1], and serum IgG antibody responses to three periodontal pathogens (Aggregatibacter actinomyce-temcomitans, Porphyromonas gingivalis, Treponema denticola) and five commensal oral microorganisms (Veillonella parvula, Streptococcus sanguis, Prevotella loescheii, Actinomyces naeslundii, Capnocytophaga ochracea).

RESULTS

The patients were stratified into health (n = 30), gingivitis (n = 55) and periodontitis (n = 184); cotinine levels correlated with reported smoking habits in health, less so with gingivitis, and were not correlated in periodontitis. Of the inflammatory mediators/acute phase proteins, only IL-1ß levels were positively associated (p < 0.001) with the pack years and cotinine levels. As might be predicted, patients with periodontitis smoked more (p < 0.001) and had higher levels of cotinine. IL-1ß and antibody to A. actinomycetemcomitans, P. gingivalis and T. denticola were significantly higher in the patients with periodontitis than either patients with gingivitis or who were healthy.

CONCLUSIONS

Generally, antibody to the pathogens and commensals was lower with decreased cotinine levels. Smoking exacerbated differences in both inflammatory mediators and three antibody in periodontal disease compared to healthy subjects.

Occurrence of red complex microorganisms and Aggregatibacter actinomycetemcomitans in patients with diabetes

AIM

The aim of the present study was to analyze the occurrence of Porphyromonas gingivalis (P. gingivalis), Tannerella forsythia (T. forsythia), Treponema denticola (T. denticola), and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in patients with diabetes.

METHODS

Periodontal and diabetic parameters and subgingival biofilm samples were obtained from 60 patients with diabetes and 62 patients without diabetes. By using polymerase chain reaction, the prevalence of red complex microorganisms (P. gingivalis, T. forsythia, and T. denticola) and A. actinomycetemcomitans were determined. Descriptive and non-parametric statistical analyses between groups were performed (Kruskal-Wallis, Mann-Whitney U-test, and Fisher's exact test).

RESULTS

Patients with diabetes presented significantly higher periodontal attachment loss levels compared to patients without diabetes. Red complex microorganisms were detected in lower frequencies in patients with diabetes. The detection of A. actinomycetemcomitans was higher in patients with diabetes and periodontitis compared to systemically-healthy patients without periodontitis (P < 0.05). P. gingivalis was associated with periodontitis in non-diabetic patients (P < 0.05), whereas A. actinomycetemcomitans was associated with periodontitis in diabetic patients (P < 0.05).

CONCLUSIONS

The findings of the present study indicate that there might be differences in the subgingival microbiota between diabetic and non-diabetic patients. In addition, P. gingivalis and A. actinomycetemcomitans were associated with periodontitis in patients without diabetes and patients with diabetes, respectively.

Periodontitis in pregnant baboons: systemic inflammation and adaptive immune responses and pregnancy outcomes in a baboon model

BACKGROUND/OBJECTIVES

Chronic periodontal infections have been suggested to contribute to the risk of adverse pregnancy outcomes.

MATERIAL AND METHODS

This study describes the relationship of patterns of systemic inflammatory mediators and IgG antibody to 20 oral bacteria in pregnant female baboons (Papio anubis) coupled with clinical features of ligature-induced periodontitis, as risk indicators for adverse pregnancy outcomes. Animals showing a preterm delivery and/or low birth weight newborns, as well as those pregnancies resulting in spontaneous abortion, stillbirth, or fetal demise were tabulated as adverse pregnancy outcomes.

RESULTS

A significantly greater frequency of the periodontitis group neonates had a low birth weight (18.1%; p = 0.008) and decreased gestational age (9.8%). Spontaneous abortion/stillbirth/fetal demise were increased in the periodontitis (8.7%) versus the control group (3.8%) (p = 0.054). The baseline oral clinical presentation of the experimental animals did not relate to the adverse pregnancy outcomes. Animals with the greatest extent/severity of periodontitis progression during the initial ½ of gestation (ie. to mid-pregnancy) had the greatest risk for adverse pregnancy outcomes. Baseline biological parameters indicating historical responses of the animals to periodontal challenge demonstrated individual variation in selected mediators, some of which became more differential during ligature-induced periodontitis. The relationship of clinical parameters to systemic inflammatory responses was consistent with a temporal contribution to adverse pregnancy outcomes in a subset of the animals.

CONCLUSIONS

These results support a link between periodontitis and adverse pregnancy outcomes in the baboons and provide a prospective experimental model for delineating the biologic parameters that contribute to a causal relationship between chronic oral infections and birth events.

Investigation of the effect of type 2 diabetes mellitus on subgingival plaque microbiota by high-throughput 16S rDNA pyrosequencing

Diabetes mellitus is a major risk factor for chronic periodontitis. We investigated the effects of type 2 diabetes on the subgingival plaque bacterial composition by applying culture-independent 16S rDNA sequencing to periodontal bacteria isolated from four groups of volunteers: non-diabetic subjects without periodontitis, non-diabetic subjects with periodontitis, type 2 diabetic patients without periodontitis, and type 2 diabetic patients with periodontitis. A total of 71,373 high-quality sequences were produced from the V1-V3 region of 16S rDNA genes by 454 pyrosequencing. Those 16S rDNA sequences were classified into 16 phyla, 27 classes, 48 orders, 85 families, 126 genera, and 1141 species-level OTUs. Comparing periodontally healthy samples with periodontitis samples identified 20 health-associated and 15 periodontitis-associated OTUs. In the subjects with healthy periodontium, the abundances of three genera (Prevotella, Pseudomonas, and Tannerella) and nine OTUs were significantly different between diabetic patients and their non-diabetic counterparts. In the subjects carrying periodontitis, the abundances of three phyla (Actinobacteria, Proteobacteria, and Bacteriodetes), two genera (Actinomyces and Aggregatibacter), and six OTUs were also significantly different between diabetics and non-diabetics. Our results show that type 2 diabetes mellitus could alter the bacterial composition in the subgingival plaque.