215 research outputs found

    In vitro evaluation of root canals obturated with four different techniques. Part 3 : Obturation of lateral canals

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    According to Schilder,1,2,3 the main objective of endodontic treatment procedures should be the cleaning and filling of the root canal in its entire extent, including all lateral canals and apical ramifications.http://www.sada.co.zaam2013mn201

    Antimicrobial efficacy of nine different root canal irrigation solutions

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    Endodontic therapy is a debridement procedure that requires removal of the irritants from the canal and periapical tissues if the treatment is to be successful. It is well established that bacteria are the main etiological factors in the development of dentinal caries and its progression to pulpal and periapical disease. E. faecalis is the bacterial species most frequently recovered from root-filled teeth. Studies have shown that E. faecalis is able to withstand a high alkaline environment such as the one generated by calcium hydroxide. The resistance appears to be related to a cell proton-pump that is necessary for survival of the bacterium at high pH. Therefore, E. faecalis is able to form biofilms even in calcium-hydroxide-medicated root canals. In addition, under starved conditions, this resilient organism shows tolerance to sodium hypochlorite, heat, hydrogen peroxide, acid and ethanol. E. faecalis can also survive extended periods of starvation in water, within water-filled dentinal tubules, and in human serum.http://www.sada.co.zaam201

    The influence of glide path preparation on the failure rate of WaveOne reciprocating instruments

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    INTRODUCTION: The aim of this study was to determine the influence of two different glide path preparation methods on the fracture rate of the Primary 25/08 WaveOne reciprocating instrument. Preparation times for different glide path methods and total time for root canal preparation, with and without prior glide path preparation, were also calculated. MATERIALS AND METHODS: ISO 15, 0.02 taper Endo-Training- Blocks (n = 300) were selected and randomly divided into three main groups (n = 100): Group 1: no glide path (control); Group 2: glide path preparation with stainless-steel hand files; and Group 3: glide path preparation with rotary PathFiles. The time taken to prepare each glide path was recorded. The specimens in each main group were then randomly assigned into five subgroups (n=20). New Primary 25/08 WaveOne files were used for canal preparation in each subgroup. The outcome was measured by recording how many simulated canals could be shaped with one WaveOne reciprocating file in each subgroup before instrument breakage occurred. The average time it took to prepare each of the simulated canals was calculated and recorded. The data were collected and statistically analysed using the ANOVA / Bonferroni test. RESULTS: Glide path preparation with PathFiles was significantly faster than with hand files (P<0.001). After the glide path preparation had been performed with PathFiles, a greater number of simulated canals could be prepared before failure of the WaveOne file (P<0.001). Root canal preparation time was significantly shorter (P<0.001) when an initial glide path had been prepared with PathFiles. CONCLUSION : Initial glide path preparation with PathFiles resulted in shorter preparation times and allowed a higher number of simulated canals to be prepared before failure of the WaveOne instruments.http://www.sada.co.za2015-07-30am201

    Errors in root canal preparation : a review of the literature and clinical case reports

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    Chemo-mechanical preparation and the removal of infected dentine in order to eliminate microorganisms and avoid apical periodontitis remain the main objectives in endodontic treatment. Mechanical preparation of the root canal system not only provides the space for obturation but also facilitates disinfection of the root canal system through the use of irrigation solutions. Iatrogenic preparation errors affect the root canal anatomy and can result in apical canal transportation, uncentered preparations, ledge formation, or perforations. These errors are all associated with inferior outcomes of endodontic treatment. In this paper, the authors will discuss a review of the literature which considers some of these procedural errors and, using clinical case studies, will illustrate the appropriate clinical management when errors do occur.https://www.sada.co.za/the-sadjam2021Odontolog

    Expression of a Small Ubiquitin-Like Modifier Protease Increases Drought Tolerance in Wheat (Triticum aestivum L.)

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    Post-translation modification of proteins plays a critical role in cellular signaling processes. In recent years, the SUMO (Small Ubiquitin-Like Modifier) class of molecules has emerged as an influential mechanism for target protein management. SUMO proteases play a vital role in regulating pathway flux and are therefore ideal targets for manipulating stress-responses. In the present study, the expression of an Arabidopsis thaliana cysteine protease (OVERLY TOLERANT TO SALT-1, OTS1) in wheat (Triticum aestivum L.) has led to improved plant growth under water stress conditions. Transformed wheat (pUBI-OTS1) displayed enhanced growth and delayed senescence under water deficit when compared with untransformed Gamtoos-R genotype or plants carrying an empty vector. Transformed pUBI-OTS1 plants also maintained a high relative moisture content (RMC), had a higher photosynthesis rate, and also had a higher total chlorophyll content when compared to untransformed plants or plants carrying an empty vector. SUMOylation of total protein also increased in untransformed plants but not in the AtOTS1 transformed plants. Our results suggest that SUMO-proteases may influence an array of mechanisms in wheat to the advantage of the crop to be more tolerant to water stress caused by drought. This is the first report to elucidate SUMOylation effects in the hexaploid crop wheat (T. aestivum L.)

    Breaking into the conversation: cultural value and the role of the South African National Arts Festival from apartheid to democracy

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    The paper examines the value of the South African National Arts Festival (NAF) in the transition to democracy using theories of cultural capital. NAF history from 1974 to 2004 is used to argue that the Festival provided an important arena for the expression of political resistance in the 1980s and, to some degree, continues to do so today. It is concluded that an important part of the value of the arts is their ability to provide a forum for debating the goals and values of society and that individualistic utility theory is not always successful in measuring such social value

    The Q2Q^2-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron

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    The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution to the magnetic moment of the target nucleus with an energy-weighted integral of the difference of the helicity-dependent photoabsorption cross sections. The data collected by HERMES with a deuterium target are presented together with a re-analysis of previous measurements on the proton. This provides a measurement of the generalised GDH integral covering simultaneously the nucleon-resonance and the deep inelastic scattering regions. The contribution of the nucleon-resonance region is seen to decrease rapidly with increasing Q2Q^2. The DIS contribution is sizeable over the full measured range, even down to the lowest measured Q2Q^2. As expected, at higher Q2Q^2 the data are found to be in agreement with previous measurements of the first moment of g1g_1. From data on the deuteron and proton, the GDH integral for the neutron has been derived and the proton--neutron difference evaluated. This difference is found to satisfy the fundamental Bjorken sum rule at Q2=5Q^2 = 5 GeV2^2.Comment: 12 pages, 10 figure
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