1,720,993 research outputs found
Analisi attraverso scansione AFM degli effetti superficiali degli irriganti canalari (NaOCl e EDTA) sui Protaper
No full textObjective. The aim of this study was to investigate, by using atomic force microscopy (AFM), the
effects of sodium hypochlorite (NaOCl) and EDTA on the surface characteristics of ProTaper
rotary nickel titanium instruments.
Study design. A total of 20 ProTaper nickel-titanium files ( S1,S2,F1,F2), were divided in 5
groups: no immersion, immersion in 5.25% NaOCl for 5 or 10 minutes and immersion in 17%
EDTA gel for 5 or 10 minutes. Twenty areas of the surface along 3-mm section at the tip of the
files (perfect squares of 1μm x 1 μm) were analyzed by atomic force microscopy (AFM Perception,
Assing, Italy) operating in contact mode under ambient condition. Three-dimensional images (400
× 400 lines) were processed by Gwiddion software and the roughness average (Ra) and the rootmean-
square value (Rms) of the scanned surface profiles were recorded. The data were analyzed
using Student t Test.
Results. Mean Rms and Ra values for NaClO and EDTA measurements were statistically higher
than the measurements on new files ( P < 0.05).
Conclusion. The AFM results show that NaOCl and EDTA significantly increased the surface
roughness of Protaper files
Marginal Leakage of Class V Composite Restorations Assessed Using Microcomputed Tomography and Scanning Electron Microscope
No full textThe aim of the study was to compare in Class V composite restorations marginal leakage measurements obtained with microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) observations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Evaluation of surface roughness of orthodontic wires by means of atomic force microscopy
No full textIntroduzione alle cellule staminali e all’endodonzia rigenerativa
No full textThe practice of dentistry is likely to be revolutionized by biological therapies
based on growth and differentiation factors, scaffold materials and
stem cells. This approach, called regenerative dentistry, is becoming a
promising field of research which aims to replace, repair and regenerate
dental tissues in order to restore the biological function that has
been halted or compromised by injury or disease. The present review
represent an introduction to stem cell biology, with special emphasis
on stem cells derived from dental tissues. Since there has been a burst
of interest, even at mass media level, for the potential possibility to built
teeth in the laboratories, more patients are becoming aware of new
treatment options, like those based on stem cells, as potentially available
in the clinical practice. Therefore, the main objective of this article is to
make the endodontic practitioners able to answer patient’s questions
on stem cells, their properties and their potential use in regenerative
endodontics and medicine
Resistenza meccanica di ponti protesici in materiale polimerico rinforzato con fibre continue di vetro
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