Periodontal pathogens and cancer development.

Increasing evidence suggests a significant association between periodontal disease and the occurrence of various cancers. The carcinogenic potential of several periodontal pathogens has been substantiated in vitro and in vivo. This review provides a comprehensive overview of the diverse mechanisms employed by different periodontal pathogens in the development of cancer. These mechanisms induce chronic inflammation, inhibit the host's immune system, activate cell invasion and proliferation, possess anti-apoptotic activity, and produce carcinogenic substances. Elucidating these mechanisms might provide new insights for developing novel approaches for tumor prevention, therapeutic purposes, and survival improvement.

Influence of gender on periodontal outcomes: A retrospective analysis of eight randomized clinical trials.

AIMS: To explore the influence of gender on periodontal treatment outcomes in a dataset of eight RCTs conducted in Brazil, United States, and Germany. METHODS: Clinical parameters were compared between men and women with stages III/IV grades B/C generalized periodontitis at baseline and 1-year post-therapy, including scaling and root planing with or without antibiotics. RESULTS: Data from 1042 patients were analyzed. Men presented a tendency towards higher probing depth (p = .07, effect size = 0.11) and clinical attachment level (CAL) than women at baseline (p = .01, effect size = 0.16). Males also presented statistically significantly lower CAL gain at sites with CAL of 4-6 mm at 1-year post-therapy (p = .001, effect size = 0.20). Among patients with Grade B periodontitis who took antibiotics, a higher frequency of women achieved the endpoint for treatment (i.e., ≤4 sites PD ≥5 mm) at 1 year than men (p < .05, effect size = 0.12). CONCLUSION: Men enrolled in RCTs showed a slightly inferior clinical response to periodontal therapy in a limited number of sub-analyses when compared to women. These small differences did not appear to be clinically relevant. Although gender did not dictate the clinical response to periodontal treatment in this population, our findings suggest that future research should continue to explore this topic.

The role of programmed death receptor (PD-)1/PD-ligand (L)1 in periodontitis and cancer.

The programmed-death-ligand-1 (PD-L1) is an immune-modulating molecule that is constitutively expressed on various immune cells, different epithelial cells and a multitude of cancer cells. It is a costimulatory molecule that may impair T-cell mediated immune response. Ligation to the programmed-death-receptor (PD)-1, on activated T-cells and further triggering of the related signaling pathways can induce T-cells apoptosis or anergy. The upregulation of PD-L1 in various cancer types, including oral squamous cell carcinomas, was demonstrated and has been linked to immune escape of tumors and poor prognosis. A bidirectional relationship exists between the increased PD-L1 expression and periodontitis as well as the epithelial-mesenchymal transition (EMT), a process of interconversion of epithelial cells to mesenchymal cells that may induce immune escape of tumors. Interaction between exosomal PD-L1 and PD-1 on T-cells may cause immunosuppression by blocking the activation and proliferation of T-cells. The efficacy and importance of treatment with PD-1/PD-L1 checkpoint inhibitors and their prognostic influence on human cancers was demonstrated. Regarding PD-1/PD-L1 checkpoint inhibitors, resistances exist or may develop, basing on various factors. Further investigations of the underlying mechanisms will help to overcome the therapeutic limitations that result from resistances and to develop new strategies for the treatment of cancer.

PD-L1, a Potential Immunomodulator Linking Immunology and Orthodontically Induced Inflammatory Root Resorption (OIIRR): Friend or Foe?

Orthodontically induced inflammatory root resorption (OIIRR) is considered an undesired and inevitable complication induced by orthodontic forces. This inflammatory mechanism is regulated by immune cells that precede orthodontic tooth movement (OTM) and can influence the severity of OIIRR. The process of OIIRR is based on an immune response. On some occasions, the immune system attacks the dentition by inflammatory processes during orthodontic treatment. Studies on the involvement of the PD-1/PD-L1 immune checkpoint have demonstrated its role in evading immune responses, aiming to identify possible novel therapeutic approaches for periodontitis. In the field of orthodontics, the important question arises of whether PD-L1 has a role in the development of OIIRR to amplify the amount of resorption. We hypothesize that blocking of the PD-L1 immune checkpoint could be a suitable procedure to reduce the process of OIIRR during orthodontic tooth movement. This review attempts to shed light on the regulation of immune mechanisms and inflammatory responses that could influence the pathogenesis of OIIRR and to acquire knowledge about the role of PD-L1 in the immunomodulation involved in OIIRR. Possible clinical outcomes will be discussed in relation to PD-L1 expression and immunologic changes throughout the resorption process.

Immunorthodontics: PD-L1, a Novel Immunomodulator in Cementoblasts, Is Regulated by HIF-1α under Hypoxia.

Recent studies have revealed that hypoxia alters the PD-L1 expression in periodontal cells. HIF-1α is a key regulator for PD-L1. As hypoxia presents a hallmark of an orthodontically induced microenvironment, hypoxic stimulation of PD-L1 expression may play vital roles in immunorthodontics and orthodontically induced inflammatory root resorption (OIIRR). This study aims to investigate the hypoxic regulation of PD-L1 in cementoblasts, and its interaction with hypoxia-induced HIF-1α expression. The cementoblast (OCCM-30) cells (M. Somerman, NIH, NIDCR, Bethesda, Maryland) were cultured in the presence and absence of cobalt (II) chloride (CoCl2). Protein expression of PD-L1 and HIF-1α as well as their gene expression were evaluated by Western blotting and RT-qPCR. Immunofluorescence was applied to visualize the localization of the proteins within cells. The HIF-1α inhibitor (HY-111387, MedChemExpress) was added, and CRISPR/Cas9 plasmid targeting HIF-1α was transferred for further investigation by flow cytometry analysis. Under hypoxic conditions, cementoblasts undergo an up-regulation of PD-L1 expression at protein and mRNA levels. Silencing of HIF-1α using CRISPR/Cas9 indicated a major positive correlation with HIF-1α in regulating PD-L1 expression. Taken together, these findings show the influence of hypoxia on PD-L1 expression is modulated in a HIF-1α dependent manner. The HIF-1α/PD-L1 pathway may play a role in the immune response of cementoblasts. Thus, combined HIF-1α/PD-L1 inhibition could be of possible therapeutic relevance for OIIRR prevention.

Immunorthodontics: Role of HIF-1α in the Regulation of (Peptidoglycan-Induced) PD-L1 Expression in Cementoblasts under Compressive Force.

Patients with periodontitis undergoing orthodontic therapy may suffer from undesired dental root resorption. The purpose of this in vitro study was to investigate the molecular mechanisms resulting in PD-L1 expression of cementoblasts in response to infection with Porphyromonas gingivalis (P. gingivalis) peptidoglycan (PGN) and compressive force (CF), and its interaction with hypoxia-inducible factor (HIF)-1α molecule: The cementoblast (OCCM-30) cells were kinetically infected with various concentrations of P. gingivalis PGN in the presence and absence of CF. Western blotting and RT-qPCR were performed to examine the protein expression of PD-L1 and HIF-1α as well as their gene expression. Immunofluorescence was applied to visualize the localization of these proteins within cells. An HIF-1α inhibitor was added for further investigation of necroptosis by flow cytometry analysis. Releases of soluble GAS-6 were measured by ELISA. P. gingivalis PGN dose dependently stimulated PD-L1 upregulation in cementoblasts at protein and mRNA levels. CF combined with P. gingivalis PGN had synergistic effects on the induction of PD-L1. Blockade of HIF-1α inhibited the P. gingivalis PGN-inducible PD-L1 protein expression under compression, indicating an HIF-1α dependent regulation of PD-L1 induction. Concomitantly, an HIF-1α inhibitor decreased the GAS-6 release in the presence of CF and P. gingivalis PGN co-stimulation. The data suggest that PGN of P. gingivalis participates in PD-L1 up-regulation in cementoblasts. Additionally, the influence of compressive force on P. gingivalis PGN-induced PD-L1 expression occurs in HIF-1α dependently. In this regard, HIF-1α may play roles in the immune response of cementoblasts via immune-inhibitory PD-L1. Our results underline the importance of molecular mechanisms involved in bacteria-induced periodontics and root resorption.

PD-L1 Up-Regulation in Prostate Cancer Cells by Porphyromonas gingivalis.

Chronic inflammation is known to contribute to various human cancers. Porphyromonas gingivalis (P. gingivalis), is a gram-negative oral keystone pathogen that may cause severe periodontitis and expresses several virulence factors to affect the host immune system. Periodontitis is a chronic infectious disease that while progression, may cause loss of attachment and destruction of the tooth supporting tissues. Prostate cancer is one of the most common malignancies in men. Increasing evidence links periodontitis with prostate cancer, however the mechanisms explaining this relationship remain unclear. The aim of this study was to investigate the expression and signaling pathway of programmed death ligand 1 (PD-L1) in a prostate cancer cell line after infection with P. gingivalis and stimulation with P. gingivalis components to reveal the mechanism of tumor-induced immune evasion associated with bacterial infection in the tumor environment. Prostate cancer cells were infected with different concentrations of viable P. gingivalis and treated with different concentrations of heat-killed P. gingivalis and P. gingivalis cell components, including the total membrane fraction, inner membrane fraction, outer membrane fraction, cytosolic fraction and peptidoglycan (PGN). Chemical inhibitors were used to block different important molecules of signaling pathways to assess the participating signal transduction mechanisms. PD-L1 expression was detected by Western blot after 24 h of infection. PD-L1 was demonstrated to be upregulated in prostate cancer cells after infection with viable and with heat-killed P. gingivalis membrane fractions. Also isolated PGN induced PD-L1 up-regulation. The upregulation was mediated by the NOD1/NOD2 signaling pathway. No upregulation could be detected after treatment of the cells with P. gingivalis lipopolysaccharide (LPS). These results indicate, that chronic inflammatory disease can contribute to tumor immune evasion by modifying the tumor microenvironment. Thus, chronic infection possibly plays an essential role in the immune response and may promote the development and progression of prostate cancer.

Recombinant Porphyromonas gingivalis W83 FimA alters immune response and metabolic gene expression in oral squamous carcinoma cells.

OBJECTIVES: The Gram-negative anaerobic rod Porphyromonas gingivalis (P. gingivalis) is regarded as a keystone pathogen in periodontitis and expresses a multitude of virulence factors iincluding fimbriae that are enabling adherence to and invasion in cells and tissues. The progression of periodontitis is a consequence of the interaction between the host immune response and periodontal pathogens. The aim of this study was to investigate the genome-wide impact of recombinant fimbrial protein FimA from P. gingivalis W83 on the gene expression of oral squamous carcinoma cells by transcriptome analysis. MATERIALS AND METHODS: Human squamous cell carcinoma cells (SCC-25) were stimulated for 4 and 24 h with recombinant FimA. RNA sequencing was performed and differential gene expression and enrichment were analyzed using gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and REACTOME. The results of transcriptome analysis were validated using quantitative real-time polymerase chain reaction (PCR) with selected genes. RESULTS: Differential gene expression after 4 and 24 h revealed upregulation of 464 (4 h) and 179 genes (24 h) and downregulation of 69 (4 h) and 312 (24 h) genes. GO, KEGG, and REACTONE enrichment analysis identified a strong immunologic transcriptomic response signature after 4 h. After 24 h, mainly those genes were regulated, which belonged to cell metabolic pathways and replication. Real-time PCR of selected genes belonging to immune response and signaling demonstrated strong upregulation of CCL20, TNFAIP6, CXCL8, TNFAIP3, and NFkBIA after both stimulation times. CONCLUSIONS: These data shed light on the RNA transcriptome of human oral squamous carcinoma epithelial cells following stimulation with P. gingivalis FimA and identify a strong immunological gene expression response to this virulence factor. The data provide a base for future studies of molecular and cellular interactions between P. gingivalis and oral epithelium to elucidate basic mechanisms that may provide new prospects for periodontitis therapy and give new insights into the development and possible treatments of cancer.

Pathogenic Mechanisms of Fusobacterium nucleatum on Oral Epithelial Cells.

Periodontitis is an oral chronic inflammatory disease and may cause tooth loss in adults. Oral epithelial cells provide a barrier for bacteria and participate in the immune response. Fusobacterium nucleatum (F. nucleatum) is one of the common inhabitants of the oral cavity and has been identified as a potential etiologic bacterial agent of oral diseases, such as periodontitis and oral carcinomas. F. nucleatum has been shown to be of importance in the development of diverse human cancers. In the dental biofilm, it exhibits a structural role as a bridging organism, connecting primary colonizers to the largely anaerobic secondary colonizers. It expresses adhesins and is able to induce host cell responses, including the upregulation of defensins and the release of chemokines and interleukins. Like other microorganisms, its detection is achieved through germline-encoded pattern-recognition receptors (PRRs) and pathogen-associated molecular patterns (PAMPs). By identification of the pathogenic mechanisms of F. nucleatum it will be possible to develop effective methods for the diagnosis, prevention, and treatment of diseases in which a F. nucleatum infection is involved. This review summarizes the recent progress in research targeting F. nucleatum and its impact on oral epithelial cells.

Porphyromonas gingivalis W83 Membrane Components Induce Distinct Profiles of Metabolic Genes in Oral Squamous Carcinoma Cells.

Periodontitis, a chronic inflammatory disease is caused by a bacterial biofilm, affecting all periodontal tissues and structures. This chronic disease seems to be associated with cancer since, in general, inflammation intensifies the risk for carcinoma development and progression. Interactions between periodontal pathogens and the host immune response induce the onset of periodontitis and are responsible for its progression, among them Porphyromonas gingivalis (P. gingivalis), a Gram-negative anaerobic rod, capable of expressing a variety of virulence factors that is considered a keystone pathogen in periodontal biofilms. The aim of this study was to investigate the genome-wide impact of P. gingivalis W83 membranes on RNA expression of oral squamous carcinoma cells by transcriptome analysis. Human squamous cell carcinoma cells (SCC-25) were infected for 4 and 24 h with extracts from P. gingivalis W83 membrane, harvested, and RNA was extracted. RNA sequencing was performed, and differential gene expression and enrichment were analyzed using GO, KEGG, and REACTOME. The results of transcriptome analysis were validated using quantitative real-time PCR with selected genes. Differential gene expression analysis resulted in the upregulation of 15 genes and downregulation of 1 gene after 4 h. After 24 h, 61 genes were upregulated and 278 downregulated. GO, KEGG, and REACTONE enrichment analysis revealed a strong metabolic transcriptomic response signature, demonstrating altered gene expressions after 4 h and 24 h that mainly belong to cell metabolic pathways and replication. Real-time PCR of selected genes belonging to immune response, signaling, and metabolism revealed upregulated expression of CCL20, CXCL8, NFkBIA, TNFAIP3, TRAF5, CYP1A1, and NOD2. This work sheds light on the RNA transcriptome of human oral squamous carcinoma cells following stimulation with P. gingivalis membranes and identifies a strong metabolic gene expression response to this periodontal pathogen. The data provide a base for future studies of molecular and cellular interactions between P. gingivalis and oral epithelium to elucidate the basic mechanisms of periodontitis and the development of cancer.

MAPK and ß-Catenin signaling: implication and interplay in orthodontic tooth movement.

Orthodontic tooth movement (OTM) requires the orthodontic forces (compressive and tensile strain) to subject to the periodontal ligament and mechanosensory cells in the periodontium and to achieve mechanotransduction by mechanoreceptors. In the context of OTM, a diverse array of signaling pathways are activated in mechanosensory cells that modulate bone resorption and formation in in vitro and in vivo models. The underlying molecular signal transduction, such as MAPK and ß-Catenin signaling, that is involved in OTM, has been partially identified. It includes, but is not limited to genes and proteins which are related to osteogenesis, osteoclastogenesis, cementogenesis and inflammation. However, the interactive relation of ß-Catenin and MAPK signaling remains ambiguous and diverse cross-talks are acting with each other. In this comprehensive text, we review the biology of OTM and reported experimental results on the activation/inhibition of these two signaling pathways during OTM. Here, we also focus on the implications and interplays between the MAPK and ß-Catenin signaling in mechanosensory cells in response to orthodontic forces. Finally, the potential of further investigation strategies aimed at supporting orthodontic interventions are discussed. This review provides a conceptual framework for more comprehensive knowledge about signaling interaction during OTM.

Porphyromonas gingivalis induced up-regulation of PD-L1 in colon carcinoma cells.

Programmed death-ligand-1 (PD-L1) is a ligand for programmed death receptor (PD-1) that plays a major role in cell-mediated immune response; it regulates T-cell activation and regulates survival and functions of activated T cells. Expression of PD-L1 can induce chronic inflammation and activate mechanisms of immune evasion. PD-L1 is expressed in most of human carcinomas. Porphyromonas gingivalis (P. gingivalis) is a major keystone pathogen in periodontitis that invade host cells and disposes a variety of virulence factors. The aim of the present study was to clarify the signaling pathway of P. gingivalis molecules that induce PD-L1 up-regulation in colon carcinoma cells. Additionally, it was investigated which components of P. gingivalis are responsible for PD-L1 induction. Colon cancer cells (CL-11) were stimulated with total membrane (TM) fractions, peptidoglycans (PDGs) and viable P. gingivalis bacteria. Seven signaling molecule inhibitors were used: receptor-interacting serine/threonine-protein kinase 2 (RIP2) tyrosine kinase inhibitor, nucleotide-binding oligomerization domain (NOD)-like receptor 1&2 inhibitor, NOD-like receptor, nuclear factor kappa B inhibitor, c-Jun N-terminal kinases inhibitor, mitogen-activated protein/extracellular signal-regulated kinase inhibitor, mitogen activated kinase (MAPK) inhibitor. PD-L1 protein expression was examined by western blot analysis and quantitative real time PCR. It was demonstrated that the TM fraction and PDG induced up-regulation of PD-L1 expression in colon cancer cells. In conclusion, the results of this study suggest that PDG of P. gingivalis plays a major role in PD-L1 up-regulation in colon cancer cells. In addition, the mechanism of PD-L1 up-regulation depends on NOD 1 and NOD 2 and involves activation of RIP2 and MAPK signaling pathways.

Evaluation of the FDI Chairside Guide for Assessment of Periodontal Conditions: A Multicentre Observational Study.

OBJECTIVE: There is a need to develop easy-to-use tools to screen for periodontal conditions in daily practice. This study aimed to evaluate the FDI World Dental Federation "Chairside Guide" (FDI-CG) developed by the Task Team of the FDI Global Periodontal Health Project (GPHP) as a potential tool for screening. METHODS: Databases from 3 centres in Germany, Hong Kong, and Spain (n = 519) were used to evaluate the association of the FDI-CG and its individual items with the periodontitis case definitions proposed by the Centers for Disease Control and Prevention (CDC) and the American Academy of Periodontology (AAP) for population-based surveillance of periodontitis. RESULTS: Statistically significant differences were observed among the databases for the prevalence of periodontitis and the items included in the FDI-CG. The FDI-CG score and its individual components were significantly associated with the periodontal status in the individual databases and the total sample, with bleeding on probing showing the strongest association with severe periodontitis (odds ratio [OR] = 12.9, 95% CI [5.9; 28.0], P < .001, for those presenting bleeding on probing >50%), followed by age (OR = 4.8, 95% CI [1.7; 4.2], P = .004, for those older than 65 years of age). Those subjects with a FDI-CG score >10 had an OR of 54.0 (95% CI [23.5; 124.2], P < .001) and presented with severe periodontitis. A significant correlation was found between the different FDI-CG scoring categories (mild, moderate, and severe) and the categories for mild, moderate, and severe periodontitis using the Centers for Disease Control and Prevention and the American Academy of Periodontology criteria (r = 0.57, Spearman rank correlation test, P < .001). CONCLUSION: The FDI Chairside Guide may represent a suitable tool for screening the periodontal condition by general practitioners in daily dental practice.

Repeated delivery of chlorhexidine chips for the treatment of peri-implantitis: A multicenter, randomized, comparative clinical trial.

BACKGROUND: Peri-implantitis is a challenging condition to manage and is frequently treated using non-surgical debridement. The local delivery of antimicrobial agents has demonstrated benefit in mild to moderate cases of peri-implantitis. This study compared the safety and efficacy of chlorhexidine gluconate 2.5 mg chip (CHX chips) as an adjunctive treatment to subgingival debridement in patients afflicted with peri-implantitis. METHODS: A multicenter, randomized, single-blind, two-arm, parallel Phase-3 study was conducted. Peri-implantitis patients with implant pocket depths (IPD) of 5-8 mm underwent subgingival implant surface debridement followed by repeated bi-weekly supragingival plaque removal and chlorhexidine chips application (ChxC group) for 12 weeks, or similar therapy but without application of ChxC (control group). All patients were followed for 24 weeks. Plaque and gingival indices were measured at every visit whereas IPD, recession, and bleeding on probing were assessed at 8, 12, 16, 24 week. RESULTS: A total of 290 patients were included: 146 in the ChxC group and 144 in the control. At 24 weeks, a significant reduction in IPD (P = 0.01) was measured in the ChxC group (1.76 ± 1.13 mm) compared with the control group (1.54 ± 1.13 mm). IPD reduction of ≥2 mm was found in 59% and 47.2% of the implants in the ChxC and control groups, respectively (P = 0.03). Changes in gingival recession (0.29 ± 0.68 mm versus 0.15 ± 0.55 mm, P = 0.015) and relative attachment gain (1.47 ± 1.32 mm and 1.39 ± 1.27 mm, P = 0.0017) were significantly larger in the ChxC group. Patients in the ChxC group that were < 65 years exhibited significantly better responses (P < 0.02); likewise, non-smokers had similarly better response (P < 0.02). Both protocols were well tolerated, and no severe treatment-related adverse events were recorded throughout the study. CONCLUSIONS: Patients with peri-implantitis that were treated with an intensive treatment protocol of bi-weekly supragingival plaque removal and local application of chlorhexidine chips had greater mean IPD reduction and greater percentile of sites with IPD reduction of ≥2 mm as compared with bi-weekly supra-gingival plaque removal.

Reactivity of Titanium Dental Implant Surfaces in Simulated Body Fluid.

Osseointegration of titanium (Ti) implants in bone is crucial for dental implant treatment. Bacterial challenge possibly leading to peri-implantitis threatens long-term success. For the improvement of osseointegration, an understanding of materials and tissue intervention is needed. This in vitro study analyzed changes of different implant surfaces exposed to simulated body fluid (SBF). Implants were analyzed by scanning electron microscopy/X-ray photoelectron spectroscopy. Supernatants (SNs) were assessed using inductively coupled plasma-mass spectrometry (ICP-MS). Additional calcium (Ca) and phosphate (P) crystals developed (Hank's buffered salt solution (HBSS)) on implants with layered surfaces. ICP of SN demonstrated a decreased Ca/P ratio. After incubation with human serum (HS), layers appeared flattened containing <1% Ca/P. The etched/machined implants showed the formation of a surface transformation layer or coating consisting of crystalline Ca/P precipitations and a decrease in the Ca/P ratio in the supernatant. Incubation in HS induced noncrystalline coverage, and increased Ti/Ca/P was detected in supernatants. HBSS induced crystals on surfaces of modified implants and crystalline covers on nonmodified implants containing Ca/P. The serum did not show the development of HA-like structures but showed dissolving effects. Titanium surfaces show completely altered behavior when incubated in serum-containing SBF.

Proposal of a Clinical Endpoint for Periodontal Trials: The Treat-to-Target Approach.

OBJECTIVE: The selection of proper outcome measures is a critical step in clinical research. Most randomized clinical trials (RCTs) assessing the effects of initial anti-infective periodontal therapies use surrogate outcomes as primary outcome variables, such as mean changes in probing depth (PD) or in clinical attachment. However, these parameters do not reflect disease remission/control at patient level, which has led to subjective interpretations of the data from RCTs and Systematic Reviews. Based on a comprehensive analysis of 724 patients from USA, Germany and Brazil treated for periodontitis, this paper suggests that the clinical endpoint of "≤4 sites with PD≥5mm" is effective in determining disease remission/control after active periodontal treatment and therefore, may represent a pertinent endpoint for applying the treat-to-target concept in RCTs. Furthermore, regression models showed that the presence of >10% and >20% sites with bleeding on probing in the mouth post-treatment increases the risk of a patient leaving the endpoint from 1-2 years (OR=3.5 and 8.7, respectively). Researchers are encouraged to present results on this outcome when reporting their trials, as this will allow for an objective comparison across studies and facilitate systematic reviews, and consequently, the extrapolation of data from research to clinical practice.

Refractory neutrophil activation in type 2 diabetics with chronic periodontitis.

BACKGROUND: Inflammation increases diabetes mellitus type 2 (T2DM) progression and severity. T2DM patients are at high risk of the rapid development of chronic periodontitis (CP). Topical presence, high numbers, and bactericidal effects of immune cells are challenged by augmented antigen-induced inflammation, which promotes both diseases. OBJECTIVES: To investigate gingival cellular inflammatory responses in individuals with previously undiagnosed T2DM with CP or CP alone and in systemically and periodontally healthy controls (H) in vivo and to establish an ex vivo technique permitting quantitative and qualitative assessments of gingival crevicular immune cells. MATERIALS AND METHODS: T2DM + CP, CP, and H individuals (n = 10, each) received a 2-week oral hygiene regimen (OHR). Afterwards, a noninvasive sampling technique was performed to evaluate gingival inflammation induced under standardized conditions in vivo, that is, in the absence of severe periodontal destruction and inflammation at clinically healthy sites. Stimuli (casein/test or phosphate-buffered saline w/o. Ca2+ or Mg2+ , PBS(-/-) /control) were randomly applied contralaterally in the gingival sulci of participants' upper dentes canini. One day after completion of the OHR, gingival crevicular fluid (GCF) was kinetically assayed between the time of the baseline (BL) measurement and 55 minutes. Polymorphonuclear leukocyte (PMN) content (PMNGCF ) was quantitated at an optimum time of 35 minutes. PMNGCF counts reflect local inflammation. Ex vivo samples were fluorimetrically labeled, gated according to the donor's peripheral blood polymorphonuclear neutrophils (PMNPB ), and then counted, employing flow cytometry. RESULTS: PMNGCF counts in unstimulated gingival crevices (at BL) in the T2DM + CP group were higher than those in the CP and H groups. PMNGCF counts were elevated in casein vs PBS(-/-) -stimulated gingival crevices in all groups. Patients with T2DM + CP showed increased PMNGCF counts compared to those with CP (P = .035) according to scatter plots. CD45+ counts in the stimulated sites in T2DM + CP patients were higher than those in CP and H patients (P = .041). Under stimulation conditions, the CD45+ counts differed from those under placebo conditions (P = .019), indicating augmented, inducible inflammatory leukocyte infiltrate in T2DM + CP patients. CONCLUSIONS: This noninvasive technique permits quantitative assessment of (experimental) gingival inflammation in vivo, revealing an influence of T2DM + CP on the number of primary immune cells in the gingival crevice. Patients who are challenged with (local) leukocytosis are likely at risk of collateral damage to the gingival crevice neighboring tissues, favoring the severity and progression of CP and consequently T2DM (www.clinicaltrials.gov NCT01848379).

Meeting Report 1st International Academy of Periodontology Research Conference (IAPRC).

The 1st International Academy of Periodontology Research Conference (IAPRC) was successfully held in Giessen, Germany from October 2-4. The objectives of the IAPRC were: to examine the state of the art in periodontal research, to encourage new scientific collaborations and to develop new directions for research.

General genetic and acquired risk factors, and prevalence of peri-implant diseases - Consensus report of working group 1.

For decades, oral implants have been used successfully for the replacement of missing teeth. Nevertheless, peri-implant diseases have become an increasingly important issue in daily practice. In this working group, the prevalence of peri-implant mucositis and peri-implantitis, as well as different general risk factors and their impact on the onset and progression of peri-implant diseases, were discussed based on reviews reflecting the current state of evidence. The influence of smoking on the peri-implant bone-healing process and its association with peri-implantitis has been explored in the current literature, demonstrating that smoking is an important risk indicator for the development of peri-implantitis and implant loss. Compared with non-smokers, smokers have a higher potential for pathological peri-implant bone loss, which is also influenced by poor oral hygiene. Despite the fact that a growing number of genetic polymorphisms have been identified and related to periodontal diseases, there are still no genetic patterns that could act as adjuncts to clinical diagnostics in order to identify patients at higher risk of peri-implant diseases. Long-term medications, such as bisphosphonate therapy (> 3 years), may have an impact on implant loss. A higher incidence of implant failure was reported in patients using selective serotonin reuptake inhibitors in anti-depression therapy. Alcoholism (defined as more than 5 units a day) has been associated with implant loss in retrospective and case-control studies, as well as in animal studies.