Prader-Willi syndrome: Periodontal-prosthodontic rehabilitation in an adult patient.

INTRODUCTION: Prader-Willi syndrome (PWS) is a rare genetic multisystemic disease that is the most common inherited cause of severe childhood obesity. PWS patients are prone to significant oral and systemic health issues that detrimentally affect quality of life and decrease longevity. This report documents full-mouth pre-prosthetic surgical and restorative care in an adult PWS patient. CASE REPORT: The patient, a 29-year-old male, presented to the clinic accompanied by his guardians (parents) with the chief complaint that "My Teeth are breaking down and I would like to get them fixed". Periodontal and prosthetic comprehensive clinical and radiographic exams revealed a severely worn dentition, deep anterior overbite, altered passive eruption with generalized biofilm-induced gingivitis, and altered occlusal vertical dimension. Full mouth crown lengthening surgery combined with full mouth prosthodontic reconstruction was performed under parenteral sedation and local anesthesia. Completion of treatment was successful, and the patient was placed on a 3-month periodontal maintenance interval. DISCUSSION: Full mouth periodontal surgical and prosthodontic reconstruction on a PWS patient has not previously been reported in the literature. This case underscores the potential need for complex dental care in patients with this syndrome.

Dendritic cells a critical link to alveolar bone loss and systemic disease risk in periodontitis: Immunotherapeutic implications.

Extensive research in humans and animal models has begun to unravel the complex mechanisms that drive the immunopathogenesis of periodontitis. Neutrophils mount an early and rapid response to the subgingival oral microbiome, producing destructive enzymes to kill microbes. Chemokines and cytokines are released that attract macrophages, dendritic cells, and T cells to the site. Dendritic cells, the focus of this review, are professional antigen-presenting cells on the front line of immune surveillance. Dendritic cells consist of multiple subsets that reside in the epithelium, connective tissues, and major organs. Our work in humans and mice established that myeloid dendritic cells are mobilized in periodontitis. This occurs in lymphoid and nonlymphoid oral tissues, in the bloodstream, and in response to Porphyromonas gingivalis. Moreover, the dendritic cells mature in situ in gingival lamina propria, forming immune conjugates with cluster of differentiation (CD) 4+ T cells, called oral lymphoid foci. At such foci, the decisions are made as to whether to promote bone destructive T helper 17 or bone-sparing regulatory T cell responses. Interestingly, dendritic cells lack potent enzymes and reactive oxygen species needed to kill and degrade endocytosed microbes. The keystone pathogen P. gingivalis exploits this vulnerability by invading dendritic cells in the tissues and peripheral blood using its distinct fimbrial adhesins. This promotes pathogen dissemination and inflammatory disease at distant sites, such as atherosclerotic plaques. Interestingly, our recent studies indicate that such P. gingivalis-infected dendritic cells release nanosized extracellular vesicles called exosomes, in higher numbers than uninfected dendritic cells do. Secreted exosomes and inflammasome-related cytokines are a key feature of the senescence-associated secretory phenotype. Exosomes communicate in paracrine with neighboring stromal cells and immune cells to promote and amplify cellular senescence. We have shown that dendritic cell-derived exosomes can be custom tailored to target and reprogram specific immune cells responsible for inflammatory bone loss in mice. The long-term goal of these immunotherapeutic approaches, ongoing in our laboratory and others, is to promote human health and longevity.

Systemic Antibiotic Therapy Reduces Circulating Inflammatory Dendritic Cells and Treg-Th17 Plasticity in Periodontitis.

Periodontitis (PD) is a common dysbiotic inflammatory disease that leads to local bone deterioration and tooth loss. PD patients experience low-grade bacteremias with oral microbes implicated in the risk of heart disease, cancer, and kidney failure. Although Th17 effectors are vital to fighting infection, functional imbalance of Th17 effectors and regulatory T cells (Tregs) promote inflammatory diseases. In this study, we investigated, in a small pilot randomized clinical trial, whether expansion of inflammatory blood myeloid dendritic cells (DCs) and conversion of Tregs to Th17 cells could be modulated with antibiotics (AB) as part of initial therapy in PD patients. PD patients were randomly assigned to either 7 d of peroral metronidazole/amoxicillin AB treatment or no AB, along with standard care debridement and chlorhexidine mouthwash. 16s ribosomal RNA analysis of keystone pathogen Porphyromonas gingivalis and its consortium members Fusobacterium nucleatum and Streptococcus gordonii confirmed the presence of all three species in the reservoirs (subgingival pockets and blood DCs) of PD patients before treatment. Of the three species, P. gingivalis was reduced in both reservoirs 4-6 wk after therapy. Further, the frequency of CD1C+CCR6+ myeloid DCs and IL-1R1 expression on IL-17A+FOXP3+CD4+ T cells in PD patients were reduced to healthy control levels. The latter led to decreased IL-1ß-stimulated Treg plasticity in PD patients and improvement in clinical measures of PD. Overall, we identified an important, albeit short-term, beneficial role of AB therapy in reducing inflammatory DCs and Treg-Th17 plasticity in humans with PD.

Cytotoxicity and osteogenic potential of silicate calcium cements as potential protective materials for pulpal revascularization.

OBJECTIVES: In pulpal revascularization, a protective material is placed coronal to the blood clot to prevent recontamination and to facilitate osteogenic differentiation of mesenchymal stem cells to produce new dental tissues. Although mineral trioxide aggregate (MTA) has been the material of choice for clot protection, it is easily displaced into the clot during condensation. The present study evaluated the effects of recently introduced calcium silicate cements (Biodentine and TheraCal LC) on the viability and osteogenic differentiation of human dental pulp stem cells (hDPSCs) by comparing with MTA Angelus. METHODS: Cell viability was assessed using XTT assay and flow cytometry. The osteogenic potential of hDPSCs exposed to calcium silicate cements was examined using qRT-PCR for osteogenic gene expressions, alkaline phosphatase enzyme activity, Alizarin red S staining and transmission electron microscopy of extracellular calcium deposits. Parametric statistical methods were employed for analyses of significant difference among groups, with α=0.05. RESULTS: The cytotoxic effects of Biodentine and TheraCal LC on hDPSCs were time- and concentration-dependent. Osteogenic differentiation of hDPSCs was enhanced after exposure to Biodentine that was depleted of its cytotoxic components. This effect was less readily observed in hDPSCs exposed to TheraCal LC, although both cements supported extracellular mineralization better than the positive control (zinc oxide-eugenol-based cement). SIGNIFICANCE: A favorable tissue response is anticipated to occur with the use of Biodentine as a blood clot-protecting material for pulpal revascularization. Further investigations with the use of in vivo animal models are required to validate the potential adverse biological effects of TheraCal LC on hDPSCs.

Dendritic cells: microbial clearance via autophagy and potential immunobiological consequences for periodontal disease.

Dendritic cells are potent antigen-capture and antigen-presenting cells that play a key role in the initiation and regulation of the adaptive immune response. This process of immune homeostasis, as maintained by dendritic cells, is susceptible to dysregulation by certain pathogens during chronic infections. Such dysregulation may lead to disease perpetuation with potentially severe systemic consequences. Here we discuss in detail how intracellular pathogens exploit dendritic cells and escape degradation by altering or evading autophagy. This novel mechanism explains, in part, the chronic, persistent nature observed in several immuno-inflammatory diseases, including periodontal disease. We also propose a hypothetical model of the plausible role of autophagy in the context of periodontal disease. Promotion of autophagy may open new therapeutic strategies in the search of a 'cure' for periodontal disease in humans.

Porphyromonas gingivalis evasion of autophagy and intracellular killing by human myeloid dendritic cells involves DC-SIGN-TLR2 crosstalk.

Signaling via pattern recognition receptors (PRRs) expressed on professional antigen presenting cells, such as dendritic cells (DCs), is crucial to the fate of engulfed microbes. Among the many PRRs expressed by DCs are Toll-like receptors (TLRs) and C-type lectins such as DC-SIGN. DC-SIGN is targeted by several major human pathogens for immune-evasion, although its role in intracellular routing of pathogens to autophagosomes is poorly understood. Here we examined the role of DC-SIGN and TLRs in evasion of autophagy and survival of Porphyromonas gingivalis in human monocyte-derived DCs (MoDCs). We employed a panel of P. gingivalis isogenic fimbriae deficient strains with defined defects in Mfa-1 fimbriae, a DC-SIGN ligand, and FimA fimbriae, a TLR2 agonist. Our results show that DC-SIGN dependent uptake of Mfa1+P. gingivalis strains by MoDCs resulted in lower intracellular killing and higher intracellular content of P. gingivalis. Moreover, Mfa1+P. gingivalis was mostly contained within single membrane vesicles, where it survived intracellularly. Survival was decreased by activation of TLR2 and/or autophagy. Mfa1+P. gingivalis strain did not induce significant levels of Rab5, LC3-II, and LAMP1. In contrast, P. gingivalis uptake through a DC-SIGN independent manner was associated with early endosomal routing through Rab5, increased LC3-II and LAMP-1, as well as the formation of double membrane intracellular phagophores, a characteristic feature of autophagy. These results suggest that selective engagement of DC-SIGN by Mfa-1+P. gingivalis promotes evasion of antibacterial autophagy and lysosome fusion, resulting in intracellular persistence in myeloid DCs; however TLR2 activation can overcome autophagy evasion and pathogen persistence in DCs.

Efficacy of 3D conforming nickel titanium rotary instruments in eliminating canal wall bacteria from oval-shaped root canals.

OBJECTIVES: To evaluate the effectiveness of TRUShape® 3D Conforming Files, compared with Twisted Files, in reducing bacteria load from root canal walls, in the presence or absence of irrigant agitation. METHODS: Extracted human premolars with single oval-shaped canals were infected with Enterococcus faecalis. Teeth in Group I (N=10; NaOCl and QMix® 2in1 as respective initial and final irrigants) were subdivided into 4 subgroups: (A) TRUShape® instrumentation without irrigant activation; (B) TRUShape® instrumentation with sonic irrigant agitation; (C) Twisted Files without irrigant agitation; (D) Twisted Files with sonic irrigant agitation. To remove confounding factor (antimicrobial irrigants), teeth in Group II (N=10) were irrigated with sterile saline, using the same subgroup designations. Specimens before and after chemomechanical débridement were cultured for quantification of colony-forming units (CFUs). Data from each group were analyzed separately using two-factor ANOVA and Holm-Sidak multiple comparison (α=0.05). Canal wall bacteria were qualitatively examined using scanning electron microscopy (SEM) and light microscopy of Taylor-modified Brown and Brenn-stained demineralised sections. RESULTS: CFUs from subgroups in Group I were not significantly different (P=0.935). For Group II, both file type (P<0.001) and irrigant agitation (P<0.001) significantly affected log-reduction in CFU concentrations. The interaction of these two factors was not significant (P=0.601). Although SEM showed reduced canal wall bacteria, bacteria were present within dentinal tubules after rotary instrumentation, as revealed by light microscopy of longitudinal root sections. CONCLUSIONS: TRUShape® files removed significantly more canal wall bacteria than Twisted Files when used without an antibacterial irrigant; the latter is required to decontaminate dentinal tubules. CLINICAL SIGNIFICANCE: Root canal disinfection should not be focused only on a mechanistic approach. Rather, the rational choice of a rotary instrumentation system should be combined with the use of well-tested antimicrobial irrigants and delivery/agitation techniques to establish a clinically realistic chemomechanical débridement protocol.

Human periodontal ligament fibroblast responses to compression in chronic periodontitis.

AIM: Test whether human periodontal ligament fibroblasts (PDLFs) retain homeostatic responses to a physiological compressive force during chronic periodontitis. MATERIAL AND METHODS: Six cell lines were established from periodontally healthy individuals (H-PDLFs) and another six were cultured from patients diagnosed with chronic periodontitis (D-PDLFs). Compressive force at 150 psi was applied to H-and D-PDLFs for 3 h on 2 consecutive days. After compression, comparisons between H-and D-PDLFs were performed by gene expression analysis of IL-6, proteases and 84 inflammation-related targets using real-time PCR. RESULTS: Compression of H-PDLFs resulted in a significant increase only in MMP-1 mRNA. In contrast, the same compressive force on D-PDLFs produced significant increases in the expression of MMPs-1,-7,-9 and -16. Moreover, compression of H-PDLFs resulted in down-regulation of IL-6, while IL-6 was significantly up-regulated in compressed D-PDLFs. Compression of H-PDLFs slightly up-regulated 3 and significantly down-regulated 15 inflammation-related genes, while the same treatment strongly up-regulated 21 inflammation-related genes in D-PDLFs. CONCLUSION: These results suggest a fundamental difference in the inflammatory response of healthy versus diseased PDLFs under physiological compression. Maintenance of these characteristics in vitro suggests that these cells may be at least partly responsible for the persistence of inflammation and localized susceptibility in chronic periodontitis.

Pneumatic pressure bioreactor for cyclic hydrostatic stress application: mechanobiology effects on periodontal ligament cells.

A bioreactor system was developed to provide high-amplitude cyclic hydrostatic compressive stress (cHSC) using compressed air mixed commercially as needed to create partial pressures of oxygen and carbon dioxide appropriate for the cells under investigation. Operating pressures as high as 300 psi are achievable in this system at cyclic speeds of up to 0.2 Hz. In this study, ligamentous fibroblasts from human periodontal ligaments (n = 6) were compressed on two consecutive days at 150 psi for 3 h each day, and the mRNA for families of extracellular matrix protein and protease isoforms was evaluated by real-time PCR array. Several integrins were significantly upregulated, most notably alpha-3 (6.4-fold), as was SPG7 (12.1-fold). Among the collagens, Col8a1 was highly upregulated at 53.5-fold, with Col6a1, Col6a2, and Col7a1 also significantly upregulated 4.4- to 8.5-fold. MMP-1 was the most affected at 122.9-fold upregulation. MMP-14 likewise increased 17.8-fold with slight reductions for the gelatinases and a significant increase of TIMP-2 at 5.8-fold. The development of this bioreactor system and its utility in characterizing periodontal ligament fibroblast mechanobiology in intermediate-term testing hold promise for better simulating the conditions of the musculoskeletal system and the large cyclic compressive stresses joints may experience in gait, exertion, and mastication.

Leishmania major attenuates host immunity by stimulating local indoleamine 2,3-dioxygenase expression.

Inflammation stimulates immunity but can create immune privilege in some settings. Here, we show that cutaneous Leishmania major infection stimulated expression of the immune regulatory enzyme indoleamine 2,3 dioxygenase (IDO) in local lymph nodes. Induced IDO attenuated the T cell stimulatory functions of dendritic cells and suppressed local T cell responses to exogenous and nominal parasite antigens. IDO ablation reduced local inflammation and parasite burdens, as did pharmacologic inhibition of IDO in mice with established infections. IDO ablation also enhanced local expression of proinflammatory cytokines and induced some CD4(+) T cells to express interleukin (IL) 17. These findings showed that IDO induced by L. major infection attenuated innate and adaptive immune responses. Thus, IDO acts as a molecular switch regulating host responses, and IDO inhibitor drugs are a potential new approach to enhance host immunity to established leishmania infections.

Periodontal ligament fibroblasts sustain destructive immune modulators of chronic periodontitis.

BACKGROUND: In healthy periodontal tissue, innate immune responses effectively confine and suppress a bacterial insult. However, a disruption of the host-bacterial equilibrium may produce an overexpression of cytokines and lead to permanent, host-mediated tissue damage. Although such periodontal destruction primarily results from activated immune mechanisms, the site-specific damage suggests that local tissues participate in these pathologic changes. Periodontal ligament fibroblasts (PDLFs) are prominent in the periodontium and are critical in homeostasis and regeneration because they have the ability to produce multiple cytokines in response to a bacterial insult. These cells could play a role in the local pathogenesis of periodontal disease. METHODS: We studied alkaline phosphatase (ALP) activity, interleukin (IL)-6 production, and morphologic characteristics of cultured PDLFs that were isolated from periodontally healthy sites (H-PDLFs) and diseased sites (D-PDLFs) in humans. Quantitative analyses of 84 genes that are related to inflammation were performed using real-time polymerase chain reaction arrays. RESULTS: A mineralizing medium induced a significant increase of ALP in H-PDLFs, but no significant enzymatic changes were detected in D-PDLFs after such treatment. The protein and gene expression of IL6 showed a significant upregulation in D-PDLFs, which also demonstrated a significant upregulation of 54% of genes in the inflammatory gene arrays. CONCLUSIONS: To our knowledge, these results represent the first biologic evidence that D-PDLFs retain uniquely inflammatory phenotypes that could maintain localized destructive signals in periodontitis. The overexpression of proinflammatory cytokines by PDLFs could amplify local inflammation by the continuous triggering of immune responses. In addition, the location of these cells could be critical in the progression of the inflammatory front into the deeper tissues.