3,060 research outputs found

    Gene Delivery Therapeutics in the Treatment of Periodontitis and Peri-Implantitis : A State of the Art Review

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    Background: Periodontal disease is a chronic inflammatory condition that affects supporting tissues around teeth, resulting in periodontal tissue breakdown. If left untreated, periodontal disease could have serious consequences; this condition is in fact considered as the primary cause of tooth loss. Being highly prevalent among adults, periodontal disease treatment is receiving increased attention from researchers and clinicians. When this condition occurs around dental implants, the disease is termed peri-implantitis. Periodontal regeneration aims at restoring the destroyed attachment apparatus, in order to improve tooth stability and thus reduce disease progression and subsequent periodontal tissue breakdown. Although many biomaterials have been developed to promote periodontal regeneration, they still have their own set of disadvantages. As a result, regenerative medicine has been employed in the periodontal field, not only to overcome the drawbacks of the conventional biomaterials but also to ensure more predictable regenerative outcomes with minimal complications. Regenerative medicine is considered a part of the research field called tissue engineering/regenerative medicine (TE/RM), a translational field combining cell therapy, biomaterial, biomedical engineering and genetics all with the aim to replace and restore tissues or organs to their normal function using in vitro models for in vivo regeneration. In a tissue, cells are responding to different micro-environmental cues and signaling molecules, these biological factors influence cell differentiation, migration and cell responses. A central part of TE/RM therapy is introducing drugs, genetic materials or proteins to induce specific cellular responses in the cells at the site of tissue repair in order to enhance and improve tissue regeneration. In this review, we present the state of art of gene therapy in the applications of periodontal tissue and peri-implant regeneration. Purpose: We aim herein to review the currently available methods for gene therapy, which include the utilization of viral/non-viral vectors and how they might serve as therapeutic potentials in regenerative medicine for periodontal and peri-implant tissues

    Cone-beam computed tomography accuracy in pulp chamber size evaluation: An ex vivo study

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    This study aimed to assess ex vivo the accuracy of cone-beam computed tomography (CBCT), as compared to operative microscope, for evaluating pulp chamber size. A total of forty teeth were extracted for periodontal reasons and a horizontal section was done at the most apical level of the cement-enamel junction. The pulp chamber was photographed using a digital camera connected to an optical microscope. Then, the tooth was scanned with CBCT and the horizontal slide matching the anatomical section of pulp chamber was digitally stored. The pulp chamber section area was measured through image analysis software. The two methods provided similar results, either for monoradicular (P = 0.14) or multiradicular teeth (P = 0.93). Correlation was statistically significant (P < 0.0001), being the coefficient r = 0.89 and 0.94 for monoradicular and multiradicular teeth, respectively. Conclusively, CBCT is suitable for pulp chamber morphology evaluation. However, it has limitations in detecting the anatomical variability of small branches in root canal system

    An environment to share in-service training on the net: An action-research about charge in primary and middle school

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    The net was one of the determining factors in a training of a Group of 4 primary and middle school teachers (L. M. in Forni Di Sopra and C. D. F. in Villa Santina, P. C. in Tolmezzo and D. S. in Gemona, all places in the mountains of Friuli, in the Nord-East of Italy) in an action-research on the electric charge. It was developed through meetings with researchers in physics education and Exchange and sharing of experiences and projects on the net, in an environment designed for teaching activities and under the guidance of a project tutor. The environment allowed to establish different kinds of relations: between teachers, between them and researchers, between classes. It offered to teachers (two in middle school and two in primary school) a place for discussions during the design of paths to be presented to their classes, to structure and share the products of their training both during and after it, to reflect on their training path

    Antimicrobial activity, toxicity and accumulated hard-tissue debris (AHTD) removal efficacy of several chelating agents

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    Aim: To evaluate the antimicrobial, toxicity and cleaning effectiveness of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) alone and combined with cetrimide (CTR). Methodology: Cytotoxic and genotoxic effects were assessed on Chinese hamster cells V79 using the MTT, clonogenic and micronucleus assays, respectively. The bacterial inhibitory and bactericidal concentrations (MIC and MBC, respectively) were determined on a strain of Enterococcus faecalis. Antimicrobial tests were performed on a biofilm model after treatment with the chelating agents by using a biofilm eradication concentration (MBEC) and confocal laser scanning microscope (CLSM) assays. Quantification of cell biomass and percentage of live and dead cells in the biomass were assessed for each group. The percentage reduction of accumulated hard-tissue debris (AHTD) after root canal preparation and final irrigation protocols was evaluated by micro-CT. Statistical tests of one-way analysis of variance (anova), Bonferroni test, Kruskal\u2013Wallis test, Dunn\u2019s multiple comparison test and Wilcoxon matched-pairs signed-rank tests were used. Results: Cetrimide alone as well as in combination with EDTA and MA at dilutions of 1/10 and 1/100 was significantly more toxic as compared to untreated controls (P < 0.001). All tested mixtures were nontoxic at a dilution of 1/1000. EDTA retained a weak inhibitory and bactericidal effect against planktonic cells, whilst MA inhibited cells growth and killed 99.9% of the cells when diluted. CTR revealed the most prominent effect, being inhibitory and bactericidal, also when diluted. Cetrimide alone or combined with EDTA was able to remove, respectively, 40% (P < 0.01) and 60% (P < 0.001) of the entire biomass after 1 min. Conversely, MA alone and in combination with CTR did not have a significant effect on biomass reduction. After final irrigation, the AHTD volume was significantly decreased in all groups (P < 0.05). EDTA + CTR and MA + CTR were associated with a significant reduction in the percentage of AHTD on the entire root canal compared to the same solutions without surfactant. Conclusions: 7% MA was less cytotoxic in comparison with 17% EDTA. The addition of cetrimide to EDTA and MA removed accumulated hard-tissue debris effectively from the canal walls and increased their antimicrobial activity when compared to the same solutions without detergents

    Same-sign W pair production as a probe of double parton scattering at the LHC

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    We study the production of same-sign W boson pairs at the LHC in double parton interactions. Compared with simple factorised double parton distributions (dPDFs), we show that the recently developed dPDFs, GS09, lead to non-trivial kinematic correlations between the W bosons. A numerical study of the prospects for observing this process using same-sign dilepton signatures, including same-sign WWjj, di-boson and heavy flavour backgrounds, at 14 TeV centre-of-mass energy is then performed. It is shown that a small excess of same-sign dilepton events from double parton scattering over a background dominated by single scattering WZ(gamma*) production could be observed at the LHC.Comment: 14 pages, 8 figures. Added references, slight changes in the text

    pQCD Physics of multiparton interactions

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    We study production of two pairs of jets in %hard hadron--hadron collisions in view of extracting contribution of {\em double hard interactions} of three and four partons (343\to4, 444\to4). Such interactions, in spite of being power suppressed at the level of the total cross section, become comparable with the standard hard collisions of two partons, 242\to4, in the {\em back-to-back kinematics} when the transverse momentum imbalances of two pairing jets are relatively small. We express differential and total cross sections for two-dijet production in double parton collisions through the generalized two-parton distributions, 2_2GPDs \cite{BDFS1}, that contain large-distance two-parton correlations of non-perturbative origin as well as small-distance correlations due to parton evolution. We find that these large- and small-distance correlations participate in different manner in 4-jet production, and treat them in the leading logarithmic approximation of pQCD that resums collinear logarithms in all orders. A special emphasis is given to 343\to4 double hard interaction processes that occur as an interplay between large- and short-distance parton correlations and were not taken into consideration by approaches inspired by the parton model picture. We demonstrate that the 343\to4 mechanism, being of the same order in \as as the 444\to4 process, turns out to be {\em geometrically enhanced} compared to the latter and should contribute significantly to 4-jet production. The framework developed here takes into systematic consideration perturbative Q2Q^2 evolution of 2_2GPDs. It can be used as a basis for future analysis of NLO corrections to multi-parton interactions (MPI) at LHC and Tevatron colliders, in particular for improving evaluation of QCD backgrounds to new physics searches.Comment: 16 pages,4 figures Improved presentation; list of references reworked; qualitative estimate of the magnitude of different contributions in the beck-to- back region correcte

    CONVERSAR e Tensionar na Formação (des)continuada, Inventiva/inclusiva: Cartografia de uma Escola Território

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    A tese inicia com indagações sobre a formação de educadores inclusivos a partir do paradigma de rede. A concepção de homem e de mundo que orienta esta investigação aponta para a complexidade da vida, entendendo o homem e a sociedade como emaranhados em uma rede de produções, intensidades de sentidos e afetações que configuram a existência. Compreendem-se os fenômenos como produção coletiva, produção de subjetividade, onde os padrões assumidos como normais são fruto de um complexo processo de reprodução de sujeitos e reinvenção da vida através da potência de criação. O trabalho configura-se como uma investigação qualitativa móvel, onde nos perguntávamos e perguntamos acerca de como a conversação, na formação de professores se efetiva como uma forma de resistência, de criação à subjetividade capitalística? Como as conversações da formação de professores se efetivavam e inventavam modos de existência inclusivos? Realizamos uma pesquisa-intervenção porque assume o plano da experiência enquanto intervenção. Tateamos, fabricamos dispositivos produtivos para fazer emergir desde o fazer, o saber. Realizamos uma cartografia das ações e criações de profissionais de uma escola pública de Ensino Fundamental de Educação de Jovens e Adultos que trabalha nos três turnos com pessoas oriundas das camadas populares e que tiveram negado o direito de estudar. Realizamos o acompanhamento do percurso formativo de um grupo de professores da escola-território no decorrer do ano de 2014. Todos os relatos e narrativas foram registrados no diário de campo e gravados digitalmente. O material produzido foi analisado a partir das orientações da análise do discurso proposto por Foucault, buscando escapar da frágil interpretação daquilo que estaria por trás dos documentos, pois entendemos que as produções são uma realização histórica, política. As análises dos discursos nos levaram a dois platôs, duas regiões, territórios intensivos: a) A formação descontinuada que dinamiza o processo de organização do trabalho docente e b) A prática inclusiva via produção de redes colaborativas que dinamizam a escolaterritório. Uma formação em tempos de desafios inclusivos demanda ser inventiva. Na experiência junto à escola-território vimos que quando uma formação se rege por análises da implicação, onde não há linearidade dos estudos e reflexões, já que a cada encontro se conversa sobre novas experiências vividas e problemas enfrentados, proliferam redes colaborativas, fundamentais para a superação do individualismo. Uma formação que opera pela resistência produzirá agenciamentos e conexões éticas/estéticas/políticas, possibilitando a produção de outros valores, diferentes dos da sociedade neoliberal, porque fortalece a coletivização da vida, criando redes sociais territoriais. O encontro das modalidades da Educação de Jovens e Adultos e da Educação Especial pela via da formação inventiva/descontinuada/ ética/estética/política se apresenta como um forte caminho e modo de produção de uma educação equitativa, por ser pública e popular

    Four-quark stability

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    The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of meson spectroscopy, beyond the simple quark--antiquark configurations. In this talk we review some recent studies of multiquark components in the charm sector and discuss in particular exotic and non-exotic four-quark systems, both with pairwise and many-body forces.Comment: 6 pages. Article based on the presentations by J. Vijande and J.-M. Richard at the Fifth Workshop on Critical Stability, Erice, Sicil

    Immediate occlusal loading and tilted implants for the rehabilitation of the atrophic edentulous maxilla : 1-year interim results of a multicenter prospective study

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    The aims of this prospective study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants for the rehabilitation of fully edentulous maxillae and to compare the outcome of axial vs. tilted implants. MATERIAL AND METHODS: Forty-one patients with edentulous maxillae were included in the study. Each patient received a full-arch fixed bridge supported by four axial implants and two distal tilted implants. Loading was applied within 48 h from surgery. Patients were scheduled for follow-up at 6 months, 1 year and annually up to 5 years. Radiographic evaluation of marginal bone-level change was performed at 1 year. RESULTS: One patient died 4 months after surgery. Thirty patients were followed for a minimum of 1 year (range 3-42 months, mean 22.1 months). Three failures were recorded at 1-year follow-up (two axial implants and one tilted). Two more implants (one tilted and one axially placed) were lost within 18 months of loading. The 1-year implant survival rate was 98.8% for both axial and tilted implants. Prosthesis success rate was 100% at 1 year. Marginal bone loss around axial and tilted implants at 12-month evaluation was similar, being, respectively, 0.9+/-0.4 (standard deviation) mm and 0.8+/-0.5 mm. CONCLUSIONS: The present preliminary data suggest that immediate loading associated with tilted implants could be considered to be a viable treatment modality for the atrophic maxilla and that there does not seem to be a different clinical outcome between tilted and axial implants

    Plasma components and platelet activation are essential for the antimicrobial properties of autologous platelet-rich plasma : an in vitro study

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    Autologous platelet concentrates are successfully adopted in a variety of medical fields to stimulate bone and soft tissue regeneration. The rationale for their use consists in the delivery of a wide range of platelet-derived bioactive molecules that promotes wound healing. In addition, antimicrobial properties of platelet concentrates have been pointed out. In this study, the effect of the platelet concentration, of the activation step and of the presence of plasmatic components on the antimicrobial activity of pure platelet-rich plasma was investigated against gram positive bacteria isolated from oral cavity. The antibacterial activity, evaluated as the minimum inhibitory concentration, was determined through the microdilution two-fold serial method. Results seem to suggest that the antimicrobial activity of platelet-rich plasma against Enterococcus faecalis, Streptococcus agalactiae, Streptococcus oralis and Staphylococcus aureus is sustained by a co-operation between plasma components and platelet-derived factors and that the activation of coagulation is a fundamental step. The findings of this study may have practical implications in the modality of application of platelet concentrates
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