Nikos Donos

Association between overweight/obesity and periodontitis in adults. A systematic review

Overweight and obesity have been suggested to be associated with periodontitis as published in studies and narrative summaries. This project presents results of a systematic review investigating the association between overweight or obesity (as defined by the World Health Organization) and periodontitis.

Modified titanium surfaces promote accelerated osteogenic differentiation of mesenchymal stromal cells in vitro

Titanium (Ti) is the material of choice for dental and orthopaedic implants due to its highly biocompatible nature. Modification of the implant surface, either topographically (as roughness) or chemically, can promote accelerated osteogenesis in vivo and greatly increase bone-implant contact and bonding strength. In this paper, we sought to characterise the cellular and molecular responses of human bone marrow-derived mesenchymal stromal cells (hMSCs) to two modified Ti surfaces: a rough hydrophobic surface that was sand-blasted and acid-etched (SLA) and an SLA surface of the same roughness that was chemically modified to have high wettability/hydrophilicity (SLActive). A smooth polished (SMO) Ti surface was used as a control. Whilst no differences in initial cell attachment to any of the surfaces were observed, we found that hMSCs cultured on the rough surfaces underwent a decrease in cell number early in culture, yet simultaneously expressed higher levels of the osteogenic markers SPP1, RUNX2 and BSP. Furthermore, deposits of calcified matrix were observed at earlier time points on both SLA and SLActive surfaces compared to SMO and this correlated with increased expression of the osteogenic promoter WNT5A in response to the rough surfaces. Osteogenic responses to SLActive were moderately better than the hydrophobic SLA surface and gene expression studies indicate that WNT5A activation may be responsible for this increased osteogenic differentiation.

Association of the Metabolic Syndrome with Severe Periodontitis in a Large U.S. Population-Based Survey

CONTEXT Metabolic syndrome and periodontitis both have an increasing prevalence worldwide; however, limited information is available on their association. OBJECTIVE The objective of the study was to assess the association between periodontitis and the metabolic syndrome in a cross-sectional survey of a nationally representative sample of the noninstitutionalized civilians in the United States. DESIGN, SETTING, AND PARTICIPANTS Data analysis from the Third National Health and Nutrition Examination Survey on 13,994 men and women aged 17 yr or older who received periodontal examination were studied. MAIN OUTCOME MEASURES Association of diagnosis and extent of periodontitis (gingival bleeding, probing pocket depths) with the metabolic syndrome and its individual component conditions (central obesity, hypertriglyceridemia, low high-density lipoprotein-cholesterol, hypertension, and insulin resistance) were measured. Adjustment for age, sex, years of education, poverty to income ratio, ethnicity, general conditions, and smoking were considered. RESULTS The prevalence of the metabolic syndrome was 18% [95% confidence interval (CI) 16-19], 34% (95% CI 29-38), and 37% (95% CI 28-48) among individuals with no-mild, moderate, and severe periodontitis, respectively. After adjusting for confounders, participants aged older than 45 yr suffering from severe periodontitis were 2.31 times (95% CI 1.13-4.73) more likely to have the metabolic syndrome than unaffected individuals. Diagnosis of metabolic syndrome increased by 1.12 times (95% CI 1.07-1.18) per 10% increase in gingival bleeding and 1.13 times (95% CI 1.03-1.24) per 10% increase in the proportion of periodontal pockets. CONCLUSIONS Severe periodontitis is associated with metabolic syndrome in middle-aged individuals. Further studies are required to test whether improvements in oral health lead to reductions in cardiometabolic traits and the risk of metabolic syndrome or vice versa.

Is periodontal inflammation associated with raised blood pressure? Evidence from a National US survey.

There is incomplete and inconclusive evidence for the association between periodontal disease markers and arterial blood pressure, particularly from large national epidemiological studies. This study assessed the relationship between different markers of periodontal inflammation and disease with arterial blood pressure in people aged 17 years and over in USA. We analysed data from the Third National Health and Nutrition Examination Survey on 6617 men and 7377 women who received a periodontal examination. Blood pressure was analysed in both a continuous format and a binary variable for case definition of hypertension. Periodontal disease markers (extent of gingival bleeding, pocket depth, and loss of attachment, and a case definition of periodontitis) were associated on the arterial blood pressure outcomes through a series of regression models, incrementally adjusting for confounders (demographic, inflammation markers, chronic conditions, smoking, BMI, socio-economic status). All periodontal measures had significant crude associations with SBP and hypertension. Gingival bleeding, a marker of current periodontal inflammation, was the only measure consistently and significantly associated with raised SBP and an increased odds of hypertension in the US adult population throughout the adjustment process. For a 10% greater extent of gingival bleeding, the average SBP was higher by 0.5 (0.3, 0.6) mmHg in the fully adjusted model. By referring to the general population and the whole distribution of blood pressure, not only to those at higher risk for hypertension, this association might have some important implications for clinical practice and public health strategies.

Systematic review of outcome measurements and reference group(s) to evaluate and compare implant success and failure

BACKGROUND There is a lack of consensus on measures to assess implant performance in clinical research. OBJECTIVES To investigate the outcomes measures and reference groups employed to evaluate and compare implant success and failure. DATA SOURCES MEDLINE (OVID) and Web of Science with searching reference lists of included papers. STUDY ELIGIBILITY CRITERIA Inclusion: root form, titanium implants in dentate or edentulous individuals. Longitudinal studies reporting survival or success outcomes on at least 20 participants ≥ mean 5 years. STUDY APPRAISAL AND SYNTHESIS METHODS Descriptive statistics. RESULTS Two-hundred and sixteen studies were included. Implant survival was the most commonly reported primary outcome (60%) with success at 15.7%. Success constituted a wide variety of measures with little consistency. A percentage of 98.6% of studies employed the implant as the unit of analysis with little consideration of clustering within patients. The status of periodontal and general heath of study groups was unclear for more than 80% studies. The proportion of studies comprising randomized trials or using appropriate analytical methods increased from 1980 to 2011. LIMITATIONS Considers only English language and there was no author contact. CONCLUSION In view of the disparate outcome measures employed to assess dental implant performance, agreement is needed both on a core set of implant outcomes and their statistical management.

Association between interleukin‐6 promoter haplotypes and aggressive periodontitis

BACKGROUND Interleukin-6 (IL-6) polymorphisms have been shown to affect IL-6 promoter activity. This study investigated the possible role of IL-6 genetic polymorphisms and haplotypes in the predisposition to aggressive periodontitis (AgP). MATERIAL AND METHODS A case-control association study on 224 AgP patients and 231 healthy controls was performed in order to detect differences in genotype distributions of five single nucleotide polymorphisms (SNPs) located in the promoter region of the IL-6 gene. RESULTS The IL-6 -1363 polymorphism was associated with a diagnosis of AgP in subjects of all ethnicities (p=0.006, adjusted logistic regression). The -1480 SNP was associated with LAgP in subjects of all ethnicities (p=0.003). The -1480 and -6106 polymorphisms were associated with Localized AgP in Caucasians (n=24) (p=0.007 and 0.010, respectively). Haplotypes determined by the -1363 and -1480 polymorphisms were also associated with LAgP (p=0.001) in Caucasians. CONCLUSIONS This study supports the hypothesis of a link between IL-6 genetic factors and AgP and highlights the importance of two IL-6 polymorphisms (-1363 and -1480) in modulating disease phenotype and susceptibility.

Genetic dysbiosis: the role of microbial insults in chronic inflammatory diseases

Thousands of bacterial phylotypes colonise the human body and the host response to this bacterial challenge greatly influences our state of health or disease. The concept of infectogenomics highlights the importance of host genetic factors in determining the composition of human microbial biofilms and the response to this microbial challenge. We hereby introduce the term ‘genetic dysbiosis’ to highlight the role of human genetic variants affecting microbial recognition and host response in creating an environment conducive to changes in the normal microbiota. Such changes can, in turn, predispose to, and influence, diseases such as: cancer, inflammatory bowel disease, rheumatoid arthritis, psoriasis, bacterial vaginosis and periodontitis. This review presents the state of the evidence on host genetic factors affecting dysbiosis and microbial misrecognition (i.e. an aberrant response to the normal microbiota) and highlights the need for further research in this area.

Differential Regulation of Circulating Levels of Molecular Chaperones in Patients Undergoing Treatment for Periodontal Disease

Background Evidence is emerging that molecular chaperones, in addition to their intracellular protein folding actions, can act as intercellular signaling proteins with an ability to modulate leukocyte function. Recent evidence has also shown that these proteins can exist in the circulation and may be involved in disease pathogenesis. We have used periodontitis and its treatment as a model of inflammation in the human to determine its effects on levels of circulating HSP10, HSP60 and BiP. Methodology/Principal Findings A group of periodontal patients and matched controls were examined at the beginning of the study and then at 1 day and 6 months following periodontal or control therapy. Plasma levels of HSP10, HSP60 and BiP were measured by immunoassay and related to other plasma measures of inflammation. Periodontal patients had significantly less circulating levels of HSP10 or BiP compared with the controls. In contrast, more periodontal patients had intermediate levels of HSP60. Treatment of the periodontitis caused an increase in plasma levels of HSP10 although it had no effect on BiP. Treatment had no influence of HSP60 levels. Plasma HSP10 levels after therapy correlated with markers of periodontal clinical improvement. Conclusions/Significance Circulating levels of molecular chaperones are influenced by local inflammation. HSP10 is known to be an anti-inflammatory factor. The marked decrease of this circulating protein in active inflammation and its recovery post-treatment suggests that it may have a role in controlling periodontal inflammation.

The effect of loading in regenerated bone in dehiscence defects following a combined approach of bone grafting and GBR

OBJECTIVES To evaluate by histology the effect of loading on the regenerated bone at dehiscence type defects around implants when treated with a combined approach of bone grafting and guided bone regeneration (GBR). MATERIALS AND METHODS In twelve Göttingen mini-pigs, the lower premolars and first molars were extracted and the alveolar process was reduced in width. After 3 months, two Straumann SLActive (Straumann AG, Basel, Switzerland) implants were placed in each hemi-mandible. Twelve implants were placed into the reduced alveolar ridge (group P) with no further defect or treatment on the site, while on 36 implants, buccal dehiscence defects were created and treated as follows: Group T1: synthetic bone substitute (Straumann Bone Ceramic, SBC, Straumann AG). Group T2: SBC with a polyethylene glycol membrane (Straumann MembraGel, Straumann AG); Group N: the dehiscence remained untreated. Three months following implantation, long, custom-made, healing abutments were placed in one hemi-mandible only to ensure functional loading. After 2 months, histological analysis was performed. RESULTS A trend for lower residual defect height and higher bone-to-implant contact was observed in the loaded sites compared with non-loaded sites in groups P, T1 and N. In group T2, the opposite effect was observed. In terms of bone formation, sites treated with SBC grafting and GBR (group T2) exhibited the largest surface area of regenerated bone followed by T1 and N. Significant resorption of the graft particles was noted in group T2 and the graft surface area occupied by SBC was significantly higher in group T1 compared with group T2 (P < 0.05). CONCLUSIONS Loading may have a positive effect on bone-to-implant contact in implants inserted in pristine bone or inserted in dehiscence sites and treated by grafting/no grafting.

Periodontitis and redox status: a review.

Periodontal diseases are common inflammatory conditions of the supporting apparatus of the teeth which lead to early tooth loss. This review discusses the evidence for a role of reactive oxygen species in inducing periodontal tissue damage and focuses on recent evidence showing increased local and systemic alterations in the redox balance of periodontitis. An appraisal of the methods for analysis of oxidative stress in periodontal disease research is provided, showing an increase in oxidative stress measures and oxidative damage fingerprints detected in studies investigating periodontitis cases compared to healthy controls. Hypotheses on the relationships between oxidative stress and inflammatory responses and on the role of redox status in periodontal medicine are discussed. Finally, the review provides an overview of possible intervention pathways for the use of antioxidants as adjuncts to mechanical biofilm removal for the treatment of periodontitis.