1,721,039 research outputs found
Analysis of different impression techniques and materials on multiple implants through 3-dimensional laser scanner
No full textObjective: The aim of this study was to evaluate the accuracy of 7 different implant impression techniques for full-arch prostheses. Materials and Methods: A master cast simulating an edentulous arch with 4 implants was used. Seven impression techniques were tested: open tray with polyether Impregum (OTI); open tray with splint-polyether Impregum (OTSI); closed tray with polyether Impregum; open tray with polyether Ramitec; open tray with splintpolyether Ramitec; closed tray with polyether Ramitec (CTR); open tray with impression plaster (OTP). Five impressions of the master cast were taken for each technique using an impression simulator device. Casts were realized based on those impressions (n = 35). Median values of deviation from the master cast were recorded for each cast through a 3-dimensional laser scanner. Results: Only OTI (P = 0.028) and OTSI (P < 0.001) presented a statistically significant difference compared to the master cast. OTP (P = 0.99) and CTR (P = 0.10) showed median values of deviation close to zero (-0.001 and-0.003 mm, respectively). Conclusion: Stiff impression materials (such as plaster or rigid polyether) guarantee greater accuracy in cases of multiple implant impressions of patients with full-arch rehabilitations. Splinting of impression copings with acrylic resin did not improve accuracy
Survival Rate and Bone Resorption in Immediate Loading of Atrophic Maxillary Arches Using Normal and Long Implants: A Pilot Observational Study
No full textTo estimate implant survival and peri-implant bone resorption around long vs normallength implants in full-arch immediate loading rehabilitation of maxillary arches of low bone quality (D4). Materials and Methods: A total of 45 patients received two mesial normallength (10 to 15 mm) or longer (18 to 20 mm) implants and two long (18 to 20 mm) distally tilted implants. Differences in bone resorption at 24 months were assessed using the Mann- Whitney U Test. Results: At the 24-month follow-up, no significant differences were found in survival (global cumulative survival rate: 98.9%) or bone resorption (mean: 1.1 mm) between long and normal implants (P = .053). Conclusion: At 24 months, the use of long implants provides favorable survival and bone maintenance results in the immediate loading rehabilitation of low-quality maxillary arche
Peri-implant Tissue Health and Bone Resorption in Patients with Immediately Loaded, Implant-Supported, Full-Arch Prostheses
No full textTo evaluate plaque accumulation, peri-implant soft tissue inflammation, and bone resorption in patients with immediately loaded implants supporting fixed full-arch prostheses
Special Issue on Enhancement of Titanium Dental Implant/Abutment Surfaces
No full textIn the last decades, there has been an increasing effort in enhancing the surface of dental implants and abutments, as a challenge to improve the osseointegration process and implant rehabilitation success [...
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
Precision and Accuracy of a Digital Impression Scanner in Full-Arch Implant Rehabilitation
Full text linkPurpose: To evaluate the accuracy and precision of a digital scanner used to scan four implants positioned according to an immediate loading implant protocol and to assess the accuracy of an aluminum framework fabricated from a digital impression. Materials and Methods: Five master casts reproducing different edentulous maxillae with four tilted implants were used. Four scan bodies were screwed onto the low-profile abutments, and a digital intraoral scanner was used to perform five digital impressions of each master cast. To assess trueness, a metal framework of the best digital impression was produced with computeraided design/computer-assisted manufacture (CAD/CAM) technology and passive fit was assessed with the Sheffield test. Gaps between the frameworks and the implant analogs were measured with a stereomicroscope. To assess precision, three-dimensional (3D) point cloud processing software was used to measure the deviations between the five digital impressions of each cast by producing a color map. The deviation values were grouped in three classes, and differences were assessed between class 2 (representing lower discrepancies) and the assembled classes 1 and 3 (representing the higher negative and positive discrepancies, respectively). Results: The frameworks showed a mean gap of < 30 μm (range: 2 to 47 μm). A statistically significant difference was found between the two groups by the 3D point cloud software, with higher frequencies of points in class 2 than in grouped classes 1 and 3 (P < .001). Conclusion: Within the limits of this in vitro study, it appears that a digital impression may represent a reliable method for fabricating full-arch implant frameworks with good passive fit when tilted implants are present
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
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