78 research outputs found

    Discoloration after Regenerative Endodontic Procedures: A Critical Review

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    Discoloration remains an unfavourable complication of otherwise successful regenerative endodontic procedure of immature teeth with necrotic pulp. This review presents a critical view on current knowledge of discoloration sources, its treatment and possible preventive modalities, dealing mainly with the use of antibiotics, ethylendiaminotetraacetic acid, calcium hydroxide, mineral trioxide aggregate, calcium silicate cements, sodium hypochlorite and chlorhexidin during regenerative treatment and their possible interactions. Bleaching as a discoloration treatment modality is discussed as well.Keywords: Biodentin; Calcium Hydroxide; Calcium Silicate; CEM cement; Mineral Trioxide Aggregate; Regenerative Medicine; Sodium Hypochlorite; Tooth Discoloratio

    Marginal seal stability of one bottle adhesives in Class V vs. Class I cavities

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    The aim of this study was to test the influence of two different cavity configurations on marginal stability of recent one bottle "etch & rinse” and "self-etch” adhesives in Class V vs. Class I cavities, before and after thermo-mechanical loading under simulation of dentinal fluid. Forty human upper molars were selected and assigned to five experimental groups. Intrapulpal pressure was maintained during cavity preparation, restoration placement, finishing and stressing. Standardized Class I and V-Shaped Class V cavities were prepared on each tooth. Half of the margins of Class V cavities were located in enamel and half in dentin. All cavities were restored with different adhesives systems and a nano-hybrid composite. Materials were light-cured using a LED unit. Restored teeth were loaded in a computer-controlled chewing machine with 1.2 million mechanical occlusal cycles simultaneously with 3,000 thermal cycles (5-50-5°C). Impressions were made with polyvinylsiloxane of each restoration before and after loading. Gold-coated epoxy replicas were prepared for SEM examination at ×200 magnification. Significant differences between materials were found both before and after loading (Kruskal-Wallis, Bonferroni, p < 0.05). Significant differences were also found between Class I and V restorations (Wilcoxon Matched-Pairs Signed-Rank Test, p < 0.05). Even before thermo-mechanical loading, none of the groups had 100% continuous margin. Marginal seal stability of recent one bottle "etch & rinse” and "self-etch” adhesives are significantly different and susceptible to cavity configuratio

    In vitro evaluation of marginal and internal adaptation after occlusal stressing of indirect class II composite restorations with different resinous bases and interface treatments. "Post-fatigue adaptation of indirect composite restorations”

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    The present study evaluated the influence of different composite bases and surface treatments on marginal and internal adaptation of class II indirect composite restorations, after simulated occlusal loading. Thirty-two class II inlay cavities were prepared on human third molars, with margins located in cementum. A 1-mm composite base extending up to the cervical margins was applied on all dentin surfaces in the experimental groups; impressions were made and composite inlays fabricated. The following experimental conditions were tested: no liner (control group), flowable composite treated with soft air abrasion (experiment 1), flowable composite sandblasted (experiment 2) and restorative composite sandblasted (experiment 3). All specimens were submitted to 1,000,000 cycles with a 100-N eccentric load. Tooth-restoration margins were analysed semi-quantitatively by scanning electron microscopy before and after loading; internal adaptation was also evaluated after test completion. The percentage of perfect adaptation in enamel was 79.5% to 92.7% before loading and 73.3% to 81.9% after loading. Perfect adaptation to dentin was reduced before loading (54.8% to 77.6%) and after loading (41.9% to 63%), but no difference was found among groups for pre- and post-loading conditions. No debonding occurred between the base and composite luting. A significant, negative influence of cyclic loading was observed. The results of the present study support the use of flowable or restorative composites as base/liner underneath large class II restorations. Soft air abrasion represents a potential alternative to airborne particle abrasion for treating cavities before cementation. The application of a composite base underneath indirect composite restorations represents a feasible non-invasive alternative to surgical crown lengthening to relocate cavity margins from an intra-crevicular to supra-gingival positio

    In Vitro Mechanical Properties of Mineral Trioxide Aggregate in Moist and Dry Intracanal Environments

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    Introduction: The purpose of this study was to examine the microhardness and modulus of elasticity (MOE) of White ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK) after setting in moist or dry intracanal conditions. Methods and Materials: To simulate root canal system, 14 polyethylen molds with internal diameter of 1 mm and height of 12 mm were used. These molds were filled with 9-mm thick layers of White ProRoot Mineral Trioxide Aggregate (MTA; Dentsply Tulsa Dental, Tulsa, OK). The experimental group (n=7) had a damp cotton pellet with 1.5 mm height and a 1.5 mm layer of resin composite placed on it. In control group (n=7) the whole 3 mm above MTA were filled with resin composite. The specimens were kept in 37°C and relative humidity of 80% for 4 days in order to simulate physiological conditions. Specimens were longitudinally sectioned and nanoindentation tests were carried out using Berkovich indenter at loading rate of 2 mN/s at 4×5 matrices of indents which were located in the coronal, middle and apical thirds of the specimen’s cross section, to evaluate the microhardness and modulus of elasticity of the specimen to appraise the progression of the setting process. Differences were assessed using nonparametric generalized Friedman rank sum and Wilcoxon Rank-Sum tests. Results: Statistical analysis showed that there was a significant difference in microhardness and MOE between control and experimental groups at coronal (P&lt;0.001), middle (P&lt;0.001) and apical (P&lt;0.001) thirds of the simulated rod from simulated apical foramen. Kruskal-Wallis test showed no significant effect of depth on microhardness of material in experimental or control groups. Conclusion: Within limitations of this in vitro study, it seems that moist intracanal environment improves setting of MTA in various depths.Keywords: Microhardness; Mineral Trioxide Aggregate; Modulus of Elasticity; Nanoindentatio

    Clinical Study Comparison of Long-Term Effect of Dual-Chamber Pacing and Alcohol Septal Ablation in Patients with Hypertrophic Obstructive Cardiomyopathy

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    Introduction. Nonpharmacological treatment of patients with hypertrophic obstructive cardiomyopathy (HOCM) comprises surgical myectomy (SME), alcohol septal ablation (ASA), and dual-chamber (DDD) pacing. The aim of the study was to compare the long-term effect of DDD pacing and ASA in symptomatic HOCM patients. Patients and Methods. We evaluated retrospective data from three cardiocenters; there were 24 patients treated with DDD pacing included and 52 treated with ASA followed for 101 ± 49 and 87 ± 23 months, respectively. Results. In the group treated with DDD pacing, the left ventricle outflow tract gradient (LVOTG) decreased from 82 ± 44 mmHg to 21 ± 21 mmHg, and NYHA class improved from 2.7 ± 0.5 to 2.1 ± 0.6 (both &lt; 0.001). In the ASA-treated group, a decline in LVOTG from 73 ± 38 mmHg to 24 ± 26 mmHg and reduction in NYHA class from 2.8 ± 0.5 to 1.7 ± 0.8 were observed (both &lt; 0.001). The LVOTG change was similar in both groups ( = 0.264), and symptoms were more affected by ASA ( = 0.001). Conclusion. ASA and DDD pacing were similarly effective in reducing LVOTG. The symptoms improvement was more expressed in patients treated with ASA

    Epidemiologie, prevence a léčba kolorektálního karcinomu dle dostupných českých a mezinárodních dat

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    Nádory tlustého střeva a konečníku patří mezi nejčastější onkologické diagnózy. V České republice je každoročně nově diagnostikováno téměř 8 500 pacientů s kolorektálním karcinomem a přibližně 3 900 osob tomuto onemocnění každým rokem podlehne. Celková prevalence přesáhne v roce 2012 hranici 55 000 osob. Společenské, etické i ekonomické důsledky vyplývající z takto vysoké zátěže jsou zřejmé. Publikace „Epidemiologie, prevence a léčba kolorektálního karcinomu dle dostupných českých a mezinárodních dat“ přináší ucelený přehled epidemiologické a léčebné zátěže české populace touto chorobou a věnuje se krátkodobým a dlouhodobým predikcím dalšího vývoje. Situace je rovněž hodnocena v mezinárodním srovnání, neboť v hodnotách incidence a mortality kolorektálního karcinomu obsazuje ČR přední příčky evropských i světových statistik. Z mezinárodních studií však také vyplývá pozitivní poznatek, že většině nádorů tlustého střeva a konečníku lze předejít účinnou prevencí. Kromě primární prevence je zde hlavním nástrojem organizovaný populační screening, který je založen na testech krvácení do stolice a na kolonoskopii. Otázkám prevence a výsledkům screeningu kolorektálního karcinomu jsou v publikaci věnovány zvláštní kapitoly. Ačkoli nejnovější data dokládají rostoucí výkonnost českého screeningu, celkově dosažené pokrytí populace bohužel stále není dostatečné. To platí pro včasný záchyt kolorektálního karcinomu obecně, neboť v ČR je setrvale téměř 50 % nových onemocnění diagnostikováno v pokročilých klinických stadiích, a tedy s výrazně sníženou šancí na vyléčení nebo dlouhodobé přežití pacienta. Publikace rovněž hodnotí přežití dosahované u českých pacientů jakožto zásadní ukazatel výsledků léčebné péče, u kterého v posledních 15 letech zaznamenáváme statisticky významné zlepšení. Pravděpodobnost 5letého relativního přežití je u včasně diagnostikovaného kolorektálního karcinomu v klinickém stadiu i vyšší než 88%. Tato čísla opět potvrzují nutnost účinné prevence a posílení screeningu tohoto preventabilního onemocnění. V tomto směru má publikace ambici informovat odbornou i laickou veřejnost, a proto věnuje značný prostor přehledu dostupných informačních zdrojů.The book aims to inform expert and general public about epidemiology of colorectal carcinoma in the Czech Republic and priorities resulting from high population burden for prevention, diagnostics, and treatment of this severe disease. A number of invited experts assess selected information sources that representatively describe performance and quality of preventive programmes and results of CRC treatment in the Czech Republic

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    TRY plant trait database – enhanced coverage and open access

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    Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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