1,721,095 research outputs found
Factors influencing preload loss of prosthetic screws: a critical review
No full textOBJECTIVES In implant-prosthetic rehabilitation, the unscrewing of the connecting prosthetic screw is the most frequent mechanical complication, as well as preceding the fracture of the screw itself. The goal of this literature review is to analyze the factors that influence the loss of preload of prosthetic screws. MATERIALS AND METHODS A literature search was conducted on four different databases: PubMed, Scopus, Cochrane and EBSCO. The following keywords were used to search: “Screw Preload”, “Screw Tightening”, “Abutment Screw” and “Torque Loss”. The search initially provided a total of 4270 articles of which after appropriate selection only 35 were included in the review. RESULTS The selected articles have been divided into 4 main topics: screwing techniques; type of abutment and prosthetic framework; type of prosthetic screws; use of lubricating/ sealing agents. CONCLUSIONS There are several factors that influence the loss of preload of prosthetic screws. The passivity of the structures on the implants and the control of occlusion are certainly fundamental elements for preserving the health of the implant- prosthetic components and the tightening of the screws themselves. Among the tightening techniques, several authors recommend repeating the tightening after a few minutes from the first screwing. Among the types of abutments and frameworks, the tolerances, the material and the precision of the components also play an important role. The coating of the prosthetic screws, their adaptability within the thread and the shape of the screw head are also important.The use of lubricants and sealants is a very controversial factor. In addition, saliva is the most discussed factor: for some it helps to reduce the loss of preload, for others it has no influence and for still others the reduced friction between the implant-prosthetic components given by the liquid could even be harmful given the high stresses produced. It is therefore necessary to periodically check the possible unscrewing of the prosthetic screws at a clinical level in order not to incur major complications. CLINICAL SIGNIFICANCE The fitting of the prosthesis on the implants, the occlusion and the tightening of the prosthetic screws represent the basis for favoring the longterm survival of the implant prostheses and of the implants themselves. However, several factors influence the loss of preload of the prosthetic screws. In order to prevent mechanical complications at the connection level, the clinician must know the nature of these factors in relation both to the general implant prosthesis and to the implant- prosthetic system used in the single clinical cases
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Investigation of the precision of a novel jaw tracking system in recording mandibular movements: A preliminary clinical study
Full text linkObjectives: This preliminary study aimed to clinically assess the precision of a novel optical jaw tracking system (JTS) in registering mandibular movements (MMs) of protrusion and mediotrusion. Methods: Twenty healthy participants underwent recordings using Cyclops JTS (Itaka Way Med) for functional MMs of protrusion and laterotrusion by two trained clinicians. Each subject performed five registrations at different times according to a standardized pattern within one-month period. The angulations of protrusive and mediotrusive functional paths within the first 2 mm from the maximal intercuspal position (MIP) were calculated for each trace, using a data software for angle measurements. Descriptive statistics were used to assess the repeatability of the recordings for each participant and MM. Additionally, inferential statistics were carried out on standard deviation values obtained (α=0.05). Results: The overall precision for all the patients was 7.07±3.37° for the protrusion angle, 5.24±2.24° for right laterotrusion and 5.14±3.06° for left laterotrusion angles. The protrusion angle ranged from 3.08° to 13.57°, while the right and left laterotrusion ranged from 1.82° to 9.42° and from 1.58° to 10.59°, respectively. No statistically significant differences were observed between different functional MM types and gender (p > 0.05). Conclusions: Recordings functional MMs of mediotrusion and protrusion using Cyclops JTS showed consistent repeatability, regardless of gender and functional MM type. The results revealed non-negligible variations that may be due to the patients’ abilities to precisely reproduce jaw movements or to the operator's ability to consistently connect the kinesiograph. Clinical significance: Capturing functional MMs digitally and importing the data into dental CAD software is essential for virtual waxing in prosthetic rehabilitations to design a functionalized adapted occlusion. Establishing the repeatability of MM recordings by a JTS is a crucial step in better understanding this novel JTS in the market. This process could facilitate the interpretation of cusp angles, aid in CAD dynamic technical modeling, and enhance clinical data communication between clinicians and technicians in a modern workflow
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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