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Since peri-implantitis differs clinically and histopathologically from periodontitis, implant wear debris is considered to play a role in the destructive processes. This work aims to systematically review if titanium particles affect oral-related cells through changes in molecular signatures (e.g., transcriptome, proteome, epigenome), thereby promoting peri-implantitis.Leveraging three literature databases (Medline, Embase, Cochrane) a systematic search based on a priori defined PICOs was conducted: '-omics' studies examining titanium exposure in oral-related cells. After risk of bias assessments, lists of differentially expressed genes, proteins, and results of functional enrichment analyses were compiled. The significance of overlapping genes across multiple studies was assessed via Monte Carlo simulation and their ranking was verified using rank aggregation.Out of 2104 screened articles we found 12 eligible publications. A significant overlap of gene expression in oral-related cells exposed to titanium particles was found in four studies. Furthermore, changes in biological processes like immune/inflammatory or stress response as well as toll-like receptor (TLR) and mitogen-activated protein kinase (MAPK) signaling pathways were linked to titanium in transcriptome and proteome studies. Epigenetic changes caused by titanium were detected but inconsistent.An influence of titanium implant wear debris on the development and progression of peri-implantitis is plausible but needs to be proven in further studies. Limitations arise from small sample sizes of included studies and insufficient publication of re-analyzable data.

Omics analyses, including the systematic cataloging of messenger RNA and microRNA sequences or DNA methylation patterns in a cell population, organ, or tissue sample, are powerful means of generating comprehensive genome-level data sets on complex diseases. We have systematically assessed the transcriptome, microbiome, miRNome, and methylome of gingival and peri-implant tissues from human subjects and further studied the transcriptome of primary cells ex vivo, or in vitro after infection with periodontal pathogens.Our data offer new insight on the pathophysiology underlying periodontal and peri-implant diseases, a possible route to a better and earlier diagnosis of these highly prevalent chronic inflammatory diseases and thus, to a personalized and efficient treatment approach.Herein, we outline the laboratory steps required for the processing of periodontal cells and tissues for -omics analyses using current microarrays or next-generation sequencing technology.

Today, -omics analyses, including the systematic cataloging of messenger RNA and microRNA sequences or DNA methylation patterns in a cell population, organ or tissue sample, allow for an unbiased, comprehensive genome-level analysis of complex diseases, offering a large advantage over earlier "candidate" gene or pathway analyses. A primary goal in the analysis of these high-throughput assays is the detection of those features among several thousand that differ between different groups of samples. In the context of oral biology, our group has successfully utilized -omics technology to identify key molecules and pathways in different diagnostic entities of periodontal disease.A major issue when inferring biological information from high-throughput -omics studies is the fact that the sheer volume of high-dimensional data generated by contemporary technology is not appropriately analyzed using common statistical methods employed in the biomedical sciences. Furthermore, machine learning methods facilitate the detection of additional patterns, beyond the mere identification of lists of features that differ between groups.Herein, we outline a robust and well-accepted bioinformatics workflow for the initial analysis of -omics data using open-source tools. We outline a differential expression analysis pipeline that can be used for data from both arrays and sequencing experiments, and offers the possibility to account for random or fixed effects. Furthermore, we present an overview of the possibilities for a functional analysis of the obtained data including subsequent machine learning approaches in form of (i) supervised classification algorithms in class validation and (ii) unsupervised clustering in class discovery.

Objectives This systematic review assessed the influence of soft tissue augmentation procedures on marginal bone level changes in partial or fully edentulous patients. Material and methods We identified three relevant PICO questions related to soft tissue augmentation procedures and conducted a systematic search of four major electronic databases for clinical studies in systemically healthy patients receiving at least one dental implant and a minimum follow-up of one year after implant placement. The primary outcome was mean difference in marginal bone levels, and secondary outcomes were clinical and patient-related outcomes such as thickness of peri-implant mucosa, bleeding indices, and Pink Esthetic Score. Results We identified 20 publications reporting on 16 relevant comparisons. Studies varied considerably and thus only two meta-analyses could be performed. This systematic review showed that: Soft tissue augmentation either for augmentation of keratinized mucosa or soft tissue volume inconsistently had an effect on marginal bone level changes when compared to no soft tissue augmentation, but consistently improved secondary outcomes. The combination soft and hard tissue augmentation showed no statistically significant difference in terms of marginal bone level changes when compared to hard tissue augmentation alone, but resulted in less marginal soft tissue recession as shown by a meta-analysis. Soft or hard tissue augmentation performed as contour augmentations resulted in comparable marginal bone level changes. Conclusions Peri-implant soft and hard tissues seem to have a bidirectional relationship: "Bone stands hard, but soft tissue is the guard".

AIM We investigated differential DNA methylation in gingival tissues in periodontal health, gingivitis, and periodontitis, and its association with differential mRNA expression. MATERIALS AND METHODS Gingival tissues were harvested from individuals and sites with clinically healthy and intact periodontium, gingivitis, and periodontitis. Samples were processed for differential DNA methylation and mRNA expression using the IlluminaEPIC (850 K) and the IlluminaHiSeq2000 platforms, respectively. Across the three phenotypes, we identified differentially methylated CpG sites and regions, differentially expressed genes (DEGs), and genes with concomitant differential methylation at their promoters and expression were identified. The findings were validated using our earlier databases using HG-U133Plus2.0Affymetrix microarrays and Illumina (450 K) methylation arrays. RESULTS We observed 43,631 differentially methylated positions (DMPs) between periodontitis and health, and 536 DMPs between gingivitis and health (FDR

BACKGROUND: The recently published clinical practice guideline (CPG) for the treatment of periodontitis in stages I-III provided evidence-based recommendations for the treatment of periodontitis patients, defined according to the 2018 classification. Stage IV periodontitis shares the severity and complexity characteristics of stage III periodontitis, but includes the anatomical and functional sequelae of tooth and periodontal attachment loss (tooth flaring and drifting, bite collapse, etc.), which require additional interventions following completion of active periodontal therapy.AIM: To develop an S3 Level CPG for the treatment of stage IV periodontitis, focusing on the implementation of inter-disciplinary treatment approaches required to treat/rehabilitate patients following associated sequelae and tooth loss.MATERIALS AND METHODS: This S3 Level CPG was developed by the European Federation of Periodontology (EFP), following methodological guidance from the Association of Scientific Medical Societies in Germany and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process. A rigorous and transparent process included synthesis of relevant research in 13 specifically commissioned systematic reviews, evaluation of the quality and strength of evidence, the formulation of specific recommendations and a structured consensus process with leading experts and a broad base of stakeholders.RESULTS: The S3 Level CPG for the treatment of stage IV periodontitis culminated in recommendations for different interventions, including orthodontic tooth movement, tooth splinting, occlusal adjustment, tooth- or implant-supported fixed or removable dental prostheses and supportive periodontal care. Prior to treatment planning, it is critically important to undertake a definitive and comprehensive diagnosis and case evaluation, obtain relevant patient information, and engage in frequent re-evaluations during and after treatment. The periodontal component of therapy should follow the CPG for the treatment of periodontitis in stages I-III.CONCLUSIONS: The present S3 Level CPG informs clinical practice, health systems, policymakers and, indirectly, the public on the available and most effective modalities to treat patients with stage IV periodontitis and to maintain a healthy dentition over lifetime, according to the available evidence at the time of publication.

Background and Aims: To describe the biology of alveolar bone regeneration.Material and Methods: Four comprehensive reviews were performed on (a) mesenchymal cells and differentiation factors leadi ...

ObjectivesTo adapt the supranational European Federation for Periodontology (EFP) S3-Level Clinical Practice Guideline for treatment of periodontitis (stage I-III) to a UK healthcare environment, taking into account the views of a broad range of stakeholders, and patients.SourcesThis UK version is based on the supranational EFP guideline (Sanz et al., 2020) published in the Journal of Clinical Periodontology. The source guideline was developed using the S3-level methodology, which combined the assessment of formal evidence from 15 systematic reviews with a moderated consensus process of a representative group of stakeholders, and accounts for health equality, environmental factors and clinical effectiveness. It encompasses 62 clinical recommendations for the treatment of stage I–III periodontitis, based on a step-wise process mapped to the 2017 classification system.MethodologyThe UK version was developed from the source guideline using a formal process called the GRADE ADOLOPMENT framework. This framework allows for the adoption (unmodified acceptance), adaptation (acceptance with modifications) and the de novo development of clinical recommendations. Using this framework and following the S3-process, the underlying systematic reviews were updated and a representative guideline group of 75 delegates from 17 stakeholder organisations was assembled into three working groups. Following the formal S3-process, all clinical recommendations were formally assessed for their applicability to the UK and adoloped accordingly.Results and conclusionUsing the ADOLOPMENT protocol, a UK version of the EFP S3-level clinical practice guideline was developed. This guideline delivers evidence- and consensus-based clinical recommendations of direct relevance to the dental community in the UK.Clinical significanceThe aim of S3-level guidelines is to combine the evaluation of formal evidence, grading and synthesis with the clinical expertise of a broad range of stakeholders to form clinical recommendations. Herein, the first major international S3-level guideline in dentistry, the EFP guideline, was implemented for direct clinical applicability in the UK healthcare system.

Genome-wide transcriptomic analyses in whole tissues reflect the aggregate gene expression in heterogeneous cell populations comprising resident and migratory cells, and they are unable to identify cell type–specific information. We used a computational method (population-specific expression analysis [PSEA]) to decompose gene expression in gingival tissues into cell type–specific signatures for 8 cell types (epithelial cells, fibroblasts, endothelial cells, neutrophils, monocytes/macrophages, plasma cells, T cells, and B cells). We used a gene expression data set generated using microarrays from 120 persons (310 tissue samples; 241 periodontitis affected and 69 healthy). Decomposition of the whole-tissue transcriptomes identified differentially expressed genes in each of the cell types, which mapped to biologically relevant pathways, including dysregulation of Th17 cell differentiation, AGE-RAGE signaling, and epithelial-mesenchymal transition in epithelial cells. We validated selected PSEA-predicted, differentially expressed genes in purified gingival epithelial cells and B cells from an unrelated cohort ( n = 15 persons), each of whom contributed with 1 periodontitis-affected and 1 healthy gingival tissue sample. Differential expression of these genes by quantitative reverse transcription polymerase chain reaction corroborated the PSEA predictions and pointed to dysregulation of biologically important pathways in periodontitis. Collectively, our results demonstrate the robustness of the PSEA in the decomposition of gingival tissue transcriptomes and its ability to identify differentially regulated transcripts in particular cellular constituents. These genes may serve as candidates for further investigation with respect to their roles in the pathogenesis of periodontitis.

The 2017 international classification system for periodontal diseases characterises periodontitis patients based upon disease extent, severity and past experience, and in stage IV includes a treatment complexity component. In addition, taking into account well-established risk factors, it aims to estimate the risk for future attachment loss. This classification system draws upon current understanding of disease pathobiology and reflects the complex, multifactorial nature of the periodontitis. It also acknowledges individual patients' risk profiles.Classification and diagnosis are distinct but linked entities, and the inclusion of established risk factors in the system helps signpost the clinician and patient towards a more personalised approach to care provision. The European Federation of Periodontology (EFP) has recently developed an S3-level clinical treatment guideline for stages I to III periodontitis, based upon a rigorous standardised process involving 15 systematic reviews of current evidence and their synthesis by a representative group of experts and stakeholders. The aim is to guide the practitioner through the complex plethora of periodontal management options and to facilitate pragmatic decision-making in full knowledge of the evidence base.Here, we present the structured, stepwise treatment protocols developed by the EFP guideline group and highlight selected specific clinical recommendations. The adapted guidelines for the UK healthcare system will be published in early 2021.

A new periodontitis classification scheme has been adopted, in which forms of the disease previously recognized as "chronic" or "aggressive" are now grouped under a single category ("periodontitis") and are further characterized based on a multi-dimensional staging and grading system. Staging is largely dependent upon the severity of disease at presentation as well as on the complexity of disease management, while grading provides supplemental information about biological features of the disease including a history-based analysis of the rate of periodontitis progression; assessment of the risk for further progression; analysis of possible poor outcomes of treatment; and assessment of the risk that the disease or its treatment may negatively affect the general health of the patient. Necrotizing periodontal diseases, whose characteristic clinical phenotype includes typical features (papilla necrosis, bleeding, and pain) and are associated with host immune response impairments, remain a distinct periodontitis category. Endodontic-periodontal lesions, defined by a pathological communication between the pulpal and periodontal tissues at a given tooth, occur in either an acute or a chronic form, and are classified according to signs and symptoms that have direct impact on their prognosis and treatment. Periodontal abscesses are defined as acute lesions characterized by localized accumulation of pus within the gingival wall of the periodontal pocket/sulcus, rapid tissue destruction and are associated with risk for systemic dissemination.

The objective of this study was to quantitatively determine ridge contour changes after different alveolar ridge preservation techniques. An initial total of 40 patients provided a final total of 35 single-gap extraction sites. After tooth removal, the socket was subjected to one of four treatment modalities: placement of a deproteinized bovine bone mineral (DBBM; Endobon) covered with a soft tissue punch from the palate (Tx1); placement of DBBM without soft tissue punch (Tx2); placement of an adsorbable collagen membrane (Osseoguard) covering the DBBM (Tx3); and no additional treatment (control). Silicone impressions were obtained before and 6 months after tooth extraction for quantitative-volumetric evaluation on stone cast models. Bone quality and need for further bone augmentation were also noted. Tx1 and Tx3 resulted in significantly less bucco-oral tissue loss when compared to Tx2 and the control group. Premolar teeth and teeth extracted for traumatic reasons revealed significantly less tissue loss. Using barrier membranes or soft tissue punches in addition to placement of DBBM seems to be advantageous to limit bucco-oral tissue atrophy. The clinical benefit, however, is still questionable.

Analytic approaches confined to fold-change comparisons of gene expression patterns between states of health and disease are unable to distinguish between primary causal disease drivers and secondary noncausal events. Genome-wide reverse engineering approaches can facilitate the identification of candidate genes that may distinguish between causal and associative interactions and may account for the emergence or maintenance of pathologic phenotypes. In this work, we used the algorithm for the reconstruction of accurate cellular networks (ARACNE) to analyze a large gene expression profile data set (313 gingival tissue samples from a cross-sectional study of 120 periodontitis patients) obtained from clinically healthy ( n = 70) or periodontitis-affected ( n = 243) gingival sites. The generated transcriptional regulatory network of the gingival interactome was subsequently interrogated with the master regulator inference algorithm (MARINA) and gene expression signature data from healthy and periodontitis-affected gingiva. Our analyses identified 41 consensus master regulator genes (MRs), the regulons of which comprised between 25 and 833 genes. Regulons of 7 MRs ( HCLS1, ZNF823, XBP1, ZNF750, RORA, TFAP2C, and ZNF57) included >500 genes each. Gene set enrichment analysis indicated differential expression of these regulons in gingival health versus disease with a type 1 error between 2% and 0.5% and with >80% of the regulon genes in the leading edge. Ingenuity pathway analysis showed significant enrichment of 36 regulons for several pathways, while 6 regulons (those of MRs HCLS1, IKZF3, ETS1, NHLH2, POU2F2, and VAV1) were enriched for >10 pathways. Pathways related to immune system signaling and development were the ones most frequently enriched across all regulons. The unbiased analysis of genome-wide regulatory networks can enhance our understanding of the pathobiology of human periodontitis and, after appropriate validation, ultimately identify target molecules of diagnostic, prognostic, or therapeutic value.

To describe the biology of alveolar bone regeneration.Four comprehensive reviews were performed on (a) mesenchymal cells and differentiation factors leading to bone formation; (b) the critical interplay between bone resorbing and formative cells; (c) the role of osteoimmunology in the formation and maintenance of alveolar bone; and (d) the self-regenerative capacity following bone injury or tooth extraction were prepared prior to the workshop.This summary information adds to the fuller understanding of the alveolar bone regenerative response with implications to reconstructive procedures for patient oral rehabilitation. The group collectively formulated and addressed critical questions based on each of the reviews in this consensus report to advance the field. The report concludes with identified areas of future research.

AIM To cross-sectionally analyse the submucosal microbiome of peri-implantitis (PI) lesions at different severity levels. MATERIALS AND METHODS Microbial signatures of 45 submucosal plaque samples from untreated PI lesions obtained from 30 non-smoking, systemically healthy subjects were assessed by 16s sequencing. Linear mixed models were used to identify taxa with differential abundance by probing depth, after correction for age, gender, and multiple samples per subject. Network analyses were performed to identify groups of taxa with mutual occurrence or exclusion. Subsequently, the effects of peri-implant probing depth on submucosal microbial dysbiosis were calculated using the microbial dysbiosis index. RESULTS In total, we identified 337 different taxa in the submucosal microbiome of PI. Total abundance of 12 taxa correlated significantly with increasing probing depth; a significant relationship with lower probing depth was found for 16 taxa. Network analysis identified two mutually exclusive complexes associated with shallow pockets and deeper pockets, respectively. Deeper peri-implant pockets were associated with significantly increased dysbiosis. CONCLUSION Increases in peri-implant pocket depth are associated with substantial changes in the submucosal microbiome and increasing levels of dysbiosis.

MicroRNAs (miRNAs) are a family of small, noncoding RNA molecules that negatively regulate protein expression either by inhibiting initiation of the translation of mRNA or by inducing the degradation of mRNA molecules. Accumulating evidence suggests that miRNA-mediated repression of protein expression is of paramount importance in a broad range of physiologic and pathologic conditions. In particular, miRNA-induced dysregulation of molecular processes involved in inflammatory pathways has been shown to contribute to the development of chronic inflammatory diseases. In this review, first of all we provide an overview of miRNA biogenesis, the main mechanisms of action and the miRNA profiling tools currently available. Then, we summarize the available evidence supporting a specific role for miRNAs in the pathobiology of periodontitis. Based on a review of available data on the differential expression of miRNAs in gingival tissues in states of periodontal health and disease, we address specific roles for miRNAs in molecular and cellular pathways causally linked to periodontitis. Our review points to several lines of evidence suggesting the involvement of miRNAs in periodontal tissue homeostasis and pathology. Although the intricate regulatory networks affected by miRNA function are still incompletely mapped, further utilization of systems biology tools is expected to enhance our understanding of the pathobiology of periodontitis.

Background The influence of the implant micro and macrostructure on peri-implantitis is not fully understood. Purpose To determine the effect of ligature-induced peri-implantitis on three commercially available implant types. Materials and Methods Five beagle dogs were used. Two months following tooth extraction, three different implant types (BIOMET 3i T3, BIOMET 3i, Palm Beach Gardens, FL, USA; Straumann Bone Level, Straumann GmbH, Basel, Switzerland; Nobel Replace Tapered, Nobel Biocare, Gothenburg, Sweden) were placed in a randomized fashion in each hemi-mandible. Peri-implantitis was initiated by ligature placement and soft diet. Ligatures were added every 2 weeks for a total of four ligature advancements. After 2 weeks, the ligatures were removed, oral hygiene measures initiated for 3 weeks, and clinical (probing depth, mucosal recession, bleeding on probing), intrasurgical (intrasurgical defect depth, intrasurgical defect width), and radiographic (radiographic bone level) parameters assessed. Results Nobel Replace Tapered implants showed significantly higher intrasurgical defect depth, intrasurgical defect width, probing depths, and radiographic bone level when compared to BIOMET 3i T3 or Straumann Bone Level implants. Straumann Bone Level implants showed largely similar clinical outcomes to BIOMET 3i T3. No significant differences between the groups were observed for mean mucosal recession. Conclusion In an experimental peri-implantitis model, Nobel Replace Tapered implants are associated with pronounced tissue loss.

Several biologically plausible mechanisms have been proposed to mediate the association between periodontitis and atherosclerotic vascular disease (AVD), including adverse effects on vascular endothelial function. Circulating endothelial progenitor cells (cEPCs) are known to contribute to vascular repair, but limited data are available regarding the relationship between cEPC levels and periodontitis. The aims of this cross-sectional study are to investigate the levels of hemangioblastic and monocytic cEPCs in patients with periodontitis and periodontally healthy controls and to associate cEPC levels with the extent and severity of periodontitis.A total of 112 individuals (56 patients with periodontitis and 56 periodontally healthy controls, aged 26 to 65 years; mean age: 43 years) were enrolled. All participants underwent a full-mouth periodontal examination and provided a blood sample. Hemangioblastic cEPCs were assessed using flow cytometry, and monocytic cEPCs were identified using immunohistochemistry in cultured peripheral blood mononuclear cells. cEPC levels were analyzed in the entire sample, as well as in a subset of 50 pairs of patients with periodontitis/periodontally healthy controls, matched with respect to age, sex, and menstrual cycle.Levels of hemangioblastic cEPCs were approximately 2.3-fold higher in patients with periodontitis than periodontally healthy controls, after adjustments for age, sex, physical activity, systolic blood pressure, and body mass index (P = 0.001). A non-significant trend for higher levels of monocytic cEPCs in periodontitis was also observed. The levels of hemangioblastic cEPCs were positively associated with the extent of bleeding on probing, probing depth, and clinical attachment loss. Hemangioblastic and monocytic cEPC levels were not correlated (Spearman correlation coefficient 0.03, P = 0.77), suggesting that they represent independent populations of progenitor cells.These findings further support the notion that oral infections have extraoral effects and document that periodontitis is associated with a mobilization of EPCs from the bone marrow, apparently in response to systemic inflammation and endothelial injury.

Objectives To evaluate a possible relationship between gingival biotypes and gingival thickness, papilla height and gingival width. Material and methods Thirty-six adult subjects were stratified by their gingival biotype (GB), as defined by transparency of a periodontal probe through the buccal gingival margin, into “thin” (18 subjects) and “thick” (18 subjects) GB. Out of these, extreme cases (6 “very thin”, 6 “very thick”) were identified. Four different parameters were assessed: gingival thickness (GT), papilla height (PH), probing depth (PD) and gingival width (GW). Results When comparing “thin” and “thick” GB, midfacial GT (0.40 ± 0.07 vs. 0.72 ± 0.11 mm; P

The aim of this study is to compare wound healing and patient pain perception of single-incision (single-incision, modified single-incision) and trap-door surgical techniques to harvest subepithelial connective tissue grafts from the palate. Thirty-six patients were selected for root coverage procedures with subepithelial connective tissue grafts and randomly assigned to two single-incision groups or a trap-door group (n = 12/group). One week after surgery, a modified early-wound healing index (EHI), patient pain and painkiller intake were recorded. Follow-up was performed until complete epithelialization was achieved. Single-incision techniques showed significantly improved early healing over trap-door approaches. Specifically, the mean EHI was 2.50 ± 1.14 for single-incision techniques, as compared to 3.33 ± 1.30 for trap door. The incidence of secondary healing was significantly lower in the single-incision groups. Concomitantly, the cumulative dosage and duration of painkiller intake were significantly reduced, as compared to the trap-door group. Within the limits of this trial, single-incision techniques can lead to improved early healing and reduced patient pain after subepithelial connective tissue graft harvesting than trap-door techniques. Avoiding trap-door incisions for harvesting of connective tissue grafts may reduce patient morbidity.

The currently recognized principal forms of periodontitis—chronic and aggressive—lack an unequivocal, pathobiology-based foundation. We explored whether gingival tissue transcriptomes can serve as the basis for an alternative classification of periodontitis. We used cross-sectional whole-genome gene expression data from 241 gingival tissue biopsies obtained from sites with periodontal pathology in 120 systemically healthy nonsmokers with periodontitis, with available data on clinical periodontal status, subgingival microbial profiles, and serum IgG antibodies to periodontal microbiota. Adjusted model-based clustering of transcriptomic data using finite mixtures generated two distinct clusters of patients that did not align with the current classification of chronic and aggressive periodontitis. Differential expression profiles primarily related to cell proliferation in cluster 1 and to lymphocyte activation and unfolded protein responses in cluster 2. Patients in the two clusters did not differ with respect to age but presented with distinct phenotypes (statistically significantly different whole-mouth clinical measures of extent/severity, subgingival microbial burden by several species, and selected serum antibody responses). Patients in cluster 2 showed more extensive/severe disease and were more often male. The findings suggest that distinct gene expression signatures in pathologic gingival tissues translate into phenotypic differences and can provide a basis for a novel classification.

Aims Volume overload and venous congestion are typically viewed as a consequence of advanced and of acute heart failure (HF) and renal failure (RF) although it is possible that hypervolaemia itself might be a critical intermediate in the pathophysiology of these diseases. This study aimed at elucidating whether peripheral venous congestion is sufficient to promote changes in inflammatory, neurohormonal, and endothelial phenotype similar to those observed in HF and RF. Methods To experimentally model peripheral venous congestion, we developed a new method (so-called venous stress test) and applied the methodology on 24 healthy subjects (14 men, age 35 ± 2 years). Venous arm pressure was increased to ∼30 mmHg above the baseline level by inflating a tourniquet cuff around the dominant arm (test arm). Blood and endothelial cells (ECs) were sampled from test and control arm (lacking an inflated cuff) before and after 75 min of venous congestion, using angiocatheters and endovascular wires. Magnetic beads coated with EC-specific antibodies were used for EC separation; amplified mRNA was analysed by Affymetrix HG-U133 Plus 2.0 Microarray. Results Plasma interleukin-6 (IL-6), endothelin-1 (ET-1), angiotensin II (AII), vascular cell adhesion molecule-1 (VCAM-1), and chemokine (C-X-C motif) ligand 2 (CXCL2) were significantly increased in the congested arm. A total of 3437 mRNA probe sets were differentially expressed ( P < 0.05) in venous ECs before vs. after testing, including ET-1, VCAM-1, and CXCL2. Conclusion Peripheral venous congestion causes release of inflammatory mediators, neurohormones, and activation of ECs. Overall, venous congestion mimicked, notable aspects of the phenotype typical of advanced and of acute HF and RF.

Prostate cancer is the second most common cancer in men and the sixth most common cause of death from cancer in men worldwide. Currently, a sufficient pathological distinction between patients requiring further treatment and those for which active surveillance remains an option is still lacking, which leads to the problem of overtreatment. Cell proliferation is routinely assessed by detecting Ki-67 antigen. While Ki-67 is expressed throughout the interphase of proliferating cells, phosphorylation of the chromatin constituent histone H3 occurs only during the late G2 phase and mitosis thus providing a more strict assessment of the mitotic activity. We undertook this study to test whether expression of the recently introduced proliferation marker phospho-histone H3 (pHH3) in prostate carcinoma tissue sections exhibits prognostic significance in comparison with Ki-67. Protein expression of pHH3 and Ki-67 was assessed on TMA consisting of paraffin-embedded tissue from men that had undergone radical prostatectomy. The analysis included triplicate tissue cores of a total of 339 tumor foci. Immunohistochemical staining of pHH3 and Ki-67 was performed and analyzed using Definiens imaging software. Prostate cancer tissue exhibited a significantly higher frequency of pHH3-positive cells compared to benign prostate tissue. pHH3 expression was significantly correlated with Ki-67 expression. Furthermore, statistical analysis revealed positive correlation between pHH3 expression and PSA levels at diagnosis and in addition negatively correlated with overall survival. In contrast to Ki-67 staining, pHH3 expression did not correlate with Gleason grade. Our data point to a conceivable role of pHH3 as prognostic biomarker in prostate carcinoma.

Periodontitis is a highly prevalent, biofilm-mediated chronic inflammatory disease that results in the loss of the tooth-supporting tissues. It features two major clinical entities: chronic periodontitis, which is more common, and aggressive periodontitis, which usually has an early onset and a rapid progression. Natural killer (NK) cells are a distinct subgroup of lymphocytes that play a major role in the ability of the innate immune system to steer immune responses. NK cells are abundant in periodontitis lesions, and NK cell activation has been causally linked to periodontal tissue destruction. However, the exact mechanisms of their activation and their role in the pathophysiology of periodontitis are elusive. Here, we show that the predominant NK cell-activating molecule in periodontitis is CD2-like receptor activating cytotoxic cells (CRACC). We show that CRACC induction was significantly more pronounced in aggressive than chronic periodontitis and correlated positively with periodontal disease severity, subgingival levels of specific periodontal pathogens, and NK cell activation in vivo . We delineate how Aggregatibacter actinomycetemcomitans , an oral pathogen that is causally associated with aggressive periodontitis, indirectly induces CRACC on NK cells via activation of dendritic cells and subsequent interleukin 12 (IL-12) signaling. In contrast, we demonstrate that fimbriae from Porphyromonas gingivalis , a principal pathogen in chronic periodontitis, actively attenuate CRACC induction on NK cells. Our data suggest an involvement of CRACC-mediated NK cell activation in periodontal tissue destruction and point to a plausible distinction in the pathobiology of aggressive and chronic periodontitis that may help explain the accelerated tissue destruction in aggressive periodontitis.

Although contemporary high-throughput –omics methods produce high-dimensional data, the resulting wealth of information is difficult to assess using traditional statistical procedures. Machine learning methods facilitate the detection of additional patterns, beyond the mere identification of lists of features that differ between groups. Here, we demonstrate the utility of (1) supervised classification algorithms in class validation, and (2) unsupervised clustering in class discovery. We use data from our previous work that described the transcriptional profiles of gingival tissue samples obtained from subjects suffering from chronic or aggressive periodontitis (1) to test whether the two diagnostic entities were also characterized by differences on the molecular level, and (2) to search for a novel, alternative classification of periodontitis based on the tissue transcriptomes. Using machine learning technology, we provide evidence for diagnostic imprecision in the currently accepted classification of periodontitis, and demonstrate that a novel, alternative classification based on differences in gingival tissue transcriptomes is feasible. The outlined procedures allow for the unbiased interrogation of high-dimensional datasets for characteristic underlying classes, and are applicable to a broad range of –omics data.

Omics analyses, including the systematic cataloging of messenger RNA and microRNA sequences or DNA methylation patterns in a cell population, organ or tissue sample, are powerful means of generating comprehensive genome-level data sets on complex diseases. We have systematically assessed the transcriptome, miRNome and methylome of gingival tissues from subjects with different diagnostic entities of periodontal disease, and studied the transcriptome of primary cells ex vivo, or in vitro after infection with periodontal pathogens. Our data further our understanding of the pathobiology of periodontal diseases and indicate that the gingival -omes translate into discernible phenotypic characteristics and possibly support an alternative, “molecular” classification of periodontitis. Here, we outline the laboratory steps required for the processing of periodontal cells and tissues for -omics analyses using current microarrays or next-generation sequencing technology.

MicroRNAs (miRNAs) have been established as key regulators of various biological processes with possible involvement in the pathobiology of periodontal disease. Expanding our earlier observations of substantial differential expression of specific miRNAs between clinically healthy and periodontitis-affected gingival tissues, we used miRNA inhibitors (sponges) in loss-of-function experiments to investigate the involvement of specific miRNAs in the response of pocket epithelium-derived, telomerase-immortalized human gingival keratinocytes (TIGKs) to microbial infection. We constructed stable knockdown (KD) cell lines for five epithelium-expressed miRNAs (miR-126, miR-141, miR-155, miR-210, and miR-1246) and assessed their response to infection with periodontal pathogens using microarray analysis, quantitative PCR (qPCR), enzyme-linked immunosorbent assay (ELISA), and Western blot assay. miR-126 KD cells showed lower expression of interleukin 8 (IL-8) and CXCL1, both on the mRNA and protein levels, than did controls upon stimulation by heat-killed wild-type Porphyromonas gingivalis , live P. gingivalis protease-deficient mutant KDP128, and live Aggregatibacter actinomycetemcomitans . In contrast, infection of miR-155 KD and miR-210 KD cells with the same organisms resulted in higher IL-8 and CXCL1 mRNA and protein expression. These effects appeared to be regulated by NF-κB, as suggested by altered transcription and/or phosphorylation status of components of the NF-κB system. Reduced neutrophil-like HL-60 cell chemotactic activity was observed in response to infection of miR-126 KD cells, indicating that miR-126 plays an important role in immune responses. Our findings indicate that specific miRNAs regulate the expression of inflammatory cytokines in human gingival epithelial cells in response to microbial infection.

Die Parodontitis ist eine biofilminduzierte entzundliche Erkrankung des Zahnhalteapparats mit hoher und zunehmender Pravalenz in der deutschen Bevolkerung. In den letzten Jahren mehren sich Hinweise auf systemische Auswirkungen der parodontalen Infektion, insbesondere in Bezug auf Diabetes und Atherosklerose. Zwischen Parodontitis und Diabetes besteht offenbar eine bidirektionale Beziehung. Hierbei begunstigt der Diabetes die Entstehung, die Progression und den Schweregrad einer Parodontitis. Die parodontale Infektion erschwert die glykamische Einstellung des Diabetes, erhoht das Risiko Diabetes-assoziierter Komplikationen und vermutlich dessen Entstehung. Dies bedeutet, dass die Therapie parodontaler Infektionen integraler Bestandteil des Diabetesmanagements werden sollte, wohingegen die Sicherstellung einer adaquaten glykamischen Kontrolle wesentlicher Bestandteil einer erfolgreichen Parodontaltherapie ist. Parodontale Infektionen gelten daruber hinaus als ein unabhangiger Risikofaktor fur Atherosklerose und deren klinische Folgen wie zerebro- und kardiovaskulare Erkrankungen. Die positive Assoziation ist zwar nur moderat ausgepragt, aber bemerkenswert konsistent. Durch Parodontitistherapie kann ein positiver Effekt auf subklinische Marker der Atherosklerose erzielt werden.

Jonsson D, Ramberg P, Demmer RT, Kebschull M, Dahlen G, Papapanou PN. Gingival tissue transcriptomes in experimental gingivitis. J Clin Periodontol 2011; doi: 10.1111/j.1600-051X.2011.01719.x. Abstract Aims: We investigated the sequential gene expression in the gingiva during the induction and resolution of experimental gingivitis. Material and Methods: Twenty periodontally and systemically healthy non-smoking volunteers participated in a 3-week experimental gingivitis protocol, followed by debridement and 2-week regular plaque control. We recorded clinical indices and harvested gingival tissue samples from four interproximal palatal sites in half of the participants at baseline, Day 7, Day 14 and Day 21 (the “induction phase”), and at Day 21, Day 25, Day 30 and Day 35 in the other half (the “resolution phase”). RNA was extracted, amplified, reversed transcribed, amplified, labelled and hybridized using Affymetrix Human Genome U133Plus2.0 microarrays. Paired t-tests compared gene expression changes between consecutive time points. Gene ontology analyses summarized the expression patterns into biologically relevant categories. Results: The median gingival index was 0 at baseline, 2 at Day 21 and 1 at Day 35. Differential gene regulation peaked during the third week of induction and the first 4 days of resolution. Leucocyte transmigration, cell adhesion and antigen processing/presentation were the top differentially regulated pathways. Conclusions: Transcriptomic studies enhance our understanding of the pathobiology of the reversible inflammatory gingival lesion and provide a detailed account of the dynamic tissue responses during the induction and resolution of experimental gingivitis.

Introduction Periodontal diseases are the pathological manifestation of the host response against the bacterial challenge from the dental biofilm at the tooth/gingival interface. The remit of this working group was to update the existing knowledge on the infectious nature of periodontal diseases. Material and Methods The literature was systematically searched and critically reviewed. Four manuscripts were produced in specific topics identified as key areas to understand the importance of the microorganisms in the etio-pathogenesis of periodontal diseases. Results/Conclusions The results and conclusions of the review process are presented in the following papers, together with the group consensus statements aiming to answer the following questions: (1) Has the use of molecular methods for the characterization of the human oral microbiome changed our understanding of the role of bacteria in the pathogenesis of periodontal disease process? (2) Are the periodontal microbial complexes associated with specific cell and tissue responses? (3) How is the development of dental biofilms influenced by the host? (4) What can we learn about biofilm/host interactions from the study of inflammatory bowel disease? This consensus report provides answers to these questions with the most updated information on periodontal microbiology.

Kebschull M, Papapanou PN. Periodontal microbial complexes associated with specific cell and tissue responses. J Clin Periodontol 2011; 38 (Suppl. 11): 17–27. doi: 10.1111/j.1600-051X.2010.01668.x. Abstract Aims: In this review, we summarize data on the association between specific periodontal bacterial profiles and tissue gene/protein expression, generated from cell culture models and in vivo studies. Material and Methods: A PubMed search was conducted to identify publications related to the effects of periodontal microbiota on host cells/tissues. Results and Conclusions: The data indicate the presence of specific host tissue responses to particular microbial complexes, evident by differential regulation of gene or protein expression, ultimately resulting in distinct clinical phenotypes. Transcriptomic analyses showed that periodontal pathogens induce a small, “common core” of differentially regulated genes encoding for an inflammatory response, and a larger variable set of genes that may reflect pathogen-specific cellular responses. Limitations of available studies include (i) the unclear role of hundreds of subgingival species not yet investigated, (ii) the fact that in vitro studies utilizing single populations of oral cells challenged with mono-infections of planktonic bacteria may not adequately portray human periodontal diseases and (iii) the cross-sectional nature of most human studies that makes them inherently incapable of allowing temporal or causal inferences. Longitudinal studies in humans hold the potential to be superior to any model, but need to be adequately powered and controlled.

Evidence from epidemiologic studies suggests that periodontal infections are independently associated with subclinical and clinical atherosclerotic vascular disease. Although the strength of the reported associations is modest, the consistency of the data across diverse populations and a variety of exposure and outcome variables suggests that the findings are not spurious or attributable only to the effects of confounders. Analysis of limited data from interventional studies suggests that periodontal treatment generally results in favorable effects on subclinical markers of atherosclerosis, although such analysis also indicates considerable heterogeneity in responses. Experimental mechanistic in vitro and in vivo studies have established the plausibility of a link between periodontal infections and atherogenesis, and have identified biological pathways by which these effects may be mediated. However, the utilized models are mostly mono-infections of host cells by a limited number of ‘model’ periodontal pathogens, and therefore may not adequately portray human periodontitis as a polymicrobial, biofilm-mediated disease. Future research must identify in vivo pathways in humans that may (i) lead to periodontitis-induced atherogenesis, or (ii) result in treatment-induced reduction of atherosclerosis risk. Data from these studies will be essential for determining whether periodontal interventions have a role in the primary or secondary prevention of atherosclerosis.

Objectives: The aim of this study was to histometrically assess alterations of the ridge following socket preservation alone and socket preservation with additional buccal overbuilding. Material and Methods: In five beagle dogs four extraction sites were randomly subjected to one of the following treatments: Tx 1: The socket was filled with BioOss Collagen® and covered with a free gingival graft from the palate. Tx 2: The buccal bone plate was augmented using the GBR-technique, the socket was filled with BioOss Collagen® and covered with a free gingival graft. Tx 3: The buccal bone plate was forced into a buccal direction using a manual bone spreader. The socket was filled with BioOss Collagen® and covered with a free gingival graft from the palate. Tx 4: The socket was filled with BioOss Collagen® and a combined free gingival/connective tissue graft was used to cover the socket and for buccal tissue augmentation. For each experimental site, two histological sections were subjected to histometric analysis and evaluated for (i) vertical bone dimensions and (ii) horizontal bone dimensions. Results: All treatment groups showed horizontal and vertical bone loss. The mean vertical bone loss of the buccal bone plate was significantly lower in Tx 4 than in the other groups, while no statistical significant differences could be detected among the groups in the horizontal dimension. Conclusion: Overbuilding the buccal aspect in combination with socket preservation does not seem to be a suitable technique to compensate for the alterations after tooth extraction.

Objective: The progression of diabetes is associated with profound endothelial dysfunction. We tested the hypothesis that cellular stress would be detectable in ECs retrieved from arterial and venous vessels of diabetic mice. Method: We describe a method for direct isolation of well-characterised aortic and venous ECs from mice in which cells are not subjected to propagation in culture. Results: Gene expression profiling, confirmed by real-time PCR, revealed a progressive increase in markers of injury within two main gene families, EC activation and EC apoptosis, in aortic and venous ECs recovered from diabetic versus non-diabetic mice. In short-term diabetes, Il1b mRNA transcripts were higher in aortic and venous ECs of diabetic mice versus controls. In long-term diabetes, casp-1 mRNA transcripts were higher in aortic and venous ECs of diabetic mice versus controls. Conclusion: These data suggest that diabetes imparts diffuse endothelial perturbation in the arterial and venous endothelium.

Members of the interleukin (IL)-12 family constitute subunits of IL-12, -23, and -27. These ILs represent pivotal mediators in the regulation of cell-mediated immune responses and in animal models of human inflammatory bowel disease. Recent work has suggested that intestinal endothelial cells might serve as a second line of defense in bacterial sensing of invading pathogens. The purpose of this study was to examine the production of IL-12 family members in intestinal endothelial cells (HIMEC). HIMEC were stimulated with proinflammatory agents (TNF-alpha, IFN-gamma, IL-1beta) and microbial antigens [LPS, lipoteichoic acid, peptidoglycan, CpG-DNA, flagellin, poly(I:C)]. Expression of IL-12 family members and of Toll-like receptor (TLR)3 in HIMEC was assessed by real-time RT-PCR, immunostaining, flow cytometry, and immunoblot analysis. HIMEC display an induction of Epstein-Barr virus-induced gene 3 (EBI3), IL-12p35, and IL-23p19, whereas no expression of IL-12p40 and IL-27p28 was detectable. The strongest induction was induced by proinflammatory factors known to utilize the NF-kappaB pathway, and expression of EBI3 and IL-23p19 was diminished by an NF-kappaB inhibitor. HIMEC display regulated expression of TLR3. Adhesion and transmigration assays showed proinflammatory responses after HIMEC stimulation. HIMEC are capable of producing IL-12 family members as a response to microbial stimuli. The TLR3 agonist, poly(I:C), was shown to enhance leukocyte adhesion in vitro in HIMEC. Our data suggest that the intestinal microvasculature is responsive to ligands of TLR3 expressed on intestinal endothelial cells, thereby adding to the regulation of adaptive immunity and leukocyte recruitment.

The influence of the implant micro and macrostructure on peri-implantitis is not fully understood.To determine the effect of ligature-induced peri-implantitis on three commercially available implant types.Five beagle dogs were used. Two months following tooth extraction, three different implant types (BIOMET 3i T3, BIOMET 3i, Palm Beach Gardens, FL, USA; Straumann Bone Level, Straumann GmbH, Basel, Switzerland; Nobel Replace Tapered, Nobel Biocare, Gothenburg, Sweden) were placed in a randomized fashion in each hemi-mandible. Peri-implantitis was initiated by ligature placement and soft diet. Ligatures were added every 2 weeks for a total of four ligature advancements. After 2 weeks, the ligatures were removed, oral hygiene measures initiated for 3 weeks, and clinical (probing depth, mucosal recession, bleeding on probing), intrasurgical (intrasurgical defect depth, intrasurgical defect width), and radiographic (radiographic bone level) parameters assessed.Nobel Replace Tapered implants showed significantly higher intrasurgical defect depth, intrasurgical defect width, probing depths, and radiographic bone level when compared to BIOMET 3i T3 or Straumann Bone Level implants. Straumann Bone Level implants showed largely similar clinical outcomes to BIOMET 3i T3. No significant differences between the groups were observed for mean mucosal recession.In an experimental peri-implantitis model, Nobel Replace Tapered implants are associated with pronounced tissue loss.

Objectives To describe histometrical outcomes (tissue thickness, tissue height) of a porcine dermal matrix (PDX) and subepithelial connective tissue (CTG) in the treatment of dehiscence-type defects. Material and methods In five beagle dogs buccal dehiscence defects were created on both upper canines. The defects were covered in a split-mouth design either with a porcine dermal matrix or subepithelial connective tissue. After 4 months histometrical outcomes were evaluated using a nonparametric Brunner–Langer model. Results Neither in the test nor in the control specimen signs of inflammation or foreign body reaction was detected. Histometrically, no significant difference was found for tissue thickness and height between both treatment groups. Conclusions Porcine dermal matrix can be used for grafting of dehiscence-type defects. Augmentation of tissue thickness seems to be comparable to subepithelial connective tissue.

Leukocyte-specific transcript 1 (LST1) encoded peptides are involved in immunomodulation and nanotube-mediated cell–cell communication. The aim of this study was to assess the expression of LST1 in colonic epithelium and endothelium during intestinal inflammation. LST1 expression was evaluated by RT-PCR, FACS, western blot analysis, and immunohistochemistry in intestinal epithelial Caco-2 cells, human intestinal microvascular endothelial cells and in human histological specimens from inflammatory bowel disease (IBD) patients and non-IBD colitis patients. LST1 expression was significantly increased upon proinflammatory stimulation in intestinal epithelial and endothelial cells. Furthermore, LST1 tissue expression was significantly enhanced in macroscopically inflamed colonic mucosal biopsies as compared to non-affected mucosal areas. This is the first report demonstrating regulated LST1 expression in human intestinal epithelial and microvascular endothelial cells and in inflamed colonic tissue from IBD patients. Proinflammatory expression of LST1 occurs in the setting of human IBD and is not restricted to immune cell populations. Future studies are needed to further elucidate the role of soluble and membrane-expressed LST1 in the regulation of mucosal intestinal immunity and inflammation as well as to reveal possible therapeutic implications.

The angiotensin II type 1 receptor (AT1R) and the peroxisome proliferator-activated receptor γ (PPARγ) have been implicated in the pathogenesis of atherosclerosis. A number of studies have reported that AT1R inhibition or genetic AT1R disruption and PPARγ activation inhibit vascular inflammation and improve glucose and lipid metabolism, underscoring a molecular interaction of AT1R and PPARγ. We here analyzed the hypothesis that vasculoprotective anti-inflammatory and metabolic effects of AT1R inhibition are mediated by PPARγ.Female ApoE(-/-)/AT1R(-/-) mice were fedwith a high-fat and cholesterol-rich diet and received continuous treatment with the selective PPARγ antagonist GW9662 or vehicle at a rate of 700 ng/kg/min for 4 weeks using subcutaneously implanted osmotic mini-pumps. Additionally, one group of female ApoE(-/-) mice served as a control group. After treatment for 4 weeks mice were sacrificed and read-outs (plaque development, vascular inflammation and insulinsensitivity) were performed.Using AT1R deficient ApoE(-/-) mice (ApoE(-/-)/AT1R(-/-) mice) we found decreased cholesterol-induced endothelial dysfunction and atherogenesis compared to ApoE(-/-) mice. Inhibition of PPARγ by application of the specific PPARγ antagonist GW9662 significantly abolished the anti-atherogenic effects of AT1R deficiency in ApoE(-/-)/AT1R(-/-) mice (plaque area as % of control: ApoE(-/-): 39 ±5%; ApoE(-/-)/AT1R(-/-): 17 ±7%, p = 0.044 vs. ApoE(-/-); ApoE(-/-)/AT1R(-/-) + GW9662: 31 ±8%, p = 0.047 vs. ApoE(-/-)/AT1R(-/-)). Focusing on IL6 as a pro-inflammatory humoral marker we detected significantly increased IL-6 levels in GW9662-treated animals (IL-6 in pg/ml: ApoE(-/-): 230 ±16; ApoE(-/-)/AT1R(-/-): 117 ±20, p = 0.01 vs. ApoE(-/-); ApoE(-/-)/AT1R(-/-) + GW9662: 199 ±20, p = 0.01 vs. ApoE(-/-)/AT1R(-/-)), while the anti-inflammatory marker IL-10 was significantly reduced after PPARγ inhibition in GW9662 animals (IL-10 in pg/ml: ApoE(-/-): 18 ±4; ApoE(-/-)/AT1R(-/-): 55 ±12, p = 0.03 vs. ApoE(-/-); ApoE(-/-)/AT1R(-/-) + GW9662: 19 ±4, p = 0.03 vs. ApoE(-/-)/AT1R(-/-)). Metabolic parameters of glucose homeostasis (glucose and insulin tolerance test) were significantly deteriorated in ApoE(-/-)/AT1R(-/-) mice treated with GW9662 as compared to vehicle-treated ApoE(-/-)/AT1R(-/-) mice. Systolic blood pressure and plasma cholesterol levels were similar in all groups.Genetic disruption of the AT1R attenuates atherosclerosis and improves endothelial function in an ApoE(-/-) mouse model of hypercholesterolemia-induced atherosclerosis via PPARγ, indicating a significant role of PPARγ in reduced vascular inflammation, improvement of insulin sensitivity and atheroprotection of AT1R deficiency.

Periodontitis is one of the most prevalent human inflammatory diseases. The major clinical phenotypes of this polymicrobial, biofilm-mediated disease are chronic and aggressive periodontitis, the latter being characterized by a rapid course of destruction that is generally attributed to an altered immune-inflammatory response against periodontal pathogens. Still, the biological basis for the pathophysiological distinction of the two disease categories has not been well documented yet. Type I NKT cells are a lymphocyte subset with important roles in regulating immune responses to either tolerance or immunity, including immune responses against bacterial pathogens. In this study, we delineate the mechanisms of NKT cell activation in periodontal infections. We show an infiltration of type I NKT cells in aggressive, but not chronic, periodontitis lesions in vivo. Murine dendritic cells infected with aggressive periodontitis-associated Aggregatibacter actinomycetemcomitans triggered a type I IFN response followed by type I NKT cell activation. In contrast, infection with Porphyromonas gingivalis, a principal pathogen in chronic periodontitis, did not induce NKT cell activation. This difference could be explained by the absence of a type I IFN response to P. gingivalis infection. We found these IFNs to be critical for NKT cell activation. Our study provides a conceivable biological distinction between the two periodontitis subforms and identifies factors required for the activation of the immune system in response to periodontal bacteria.

The objective of this study is to compare tissue reduction following papilla-sparing and sulcular incisions in oral surgical indications. Five beagle dogs were used. Three months after tooth extraction of P2–M1, notches were prepared at the height of the interproximal gingiva into M2 and P1. Papilla-sparing and sulcular incisions were randomly performed, full-thickness flaps elevated and flaps repositioned. Three months postoperatively, tissue reduction was assessed using a digital calliper, mean values were calculated per group and analysed using a Wilcoxon matched-pair rank test. Papilla-sparing incisions revealed significantly less (p

BACKGROUND: Periodontal infections are independent risk factors for atherosclerosis. However, the exact mechanisms underlying this link are yet unclear. Here, we evaluate the in vivo effects of bacteremia with a periodontal pathogen on endothelial progenitors, bone marrow-derived cells capable of endothelial regeneration, and delineate the critical pathways for these effects. METHODS: 12-week old C57bl6 wildtype or toll-like receptor (TLR)-2 deficient mice were repeatedly intravenously challenged with 10⁹ live P. gingivalis 381 or vehicle. Numbers of Sca1+/flk1+ progenitors, circulating angiogenic cells, CFU-Hill, and late-outgrowth EPC were measured by FACS/culture. Endothelial function was assessed using isolated organ baths, reendothelization was measured in a carotid injury model. RANKL/osteoprotegerin levels were assessed by ELISA/qPCR. RESULTS: In wildtype mice challenged with intravenous P.gingivalis, numbers of Sca1+/flk1+ progenitors, CAC, CFU-Hill, and late-outgrowth EPC were strongly increased in peripheral circulation and spleen, whereas Sca1+/flk1+ progenitor numbers in bone marrow decreased. Circulating EPCs were functional, as indicated by improved endothelial function and improved reendothelization in infected mice. The osteoprotegerin/RANKL ratio was increased after P. gingivalis challenge in the bone marrow niche of wildtype mice and late-outgrowth EPC in vitro. Conversely, in mice deficient in TLR2, no increase in progenitor mobilization or osteoprotegerin/RANKL ratio was detected. CONCLUSION: Recurrent transient bacteremias, a feature of periodontitis, increase peripheral EPC counts and decrease EPC pools in the bone marrow, thereby possibly reducing overall endothelial regeneration capacity, conceivably explaining pro-atherogenic properties of periodontal infections. These effects are seemingly mediated by toll-like receptor (TLR)-2.