1,721,003 research outputs found
Maxillary sinus augmentation with a porous synthetic hydroxyapatite and bovine-derived hydroxyapatite: a comparative clinical and histologic study.
No full textThe aim of this study was to determine the clinical and histologic results of a porous synthetic hydroxyapatite (HA) compared with bovine-derived HA used in maxillary sinus augmentation.A total of 100 titanium implants were placed in 40 patients. Patients in need of maxillary sinus augmentation were divided into 2 groups. Group 1 received bovine-derived HA (20 patients with 50 implants), while group 2 received a porous synthetic HA (20 patients with 50 implants). After a healing period of 6 months, second-stage surgery was carried out. In 50 cases (25 from group 1 and 25 from group 2), bone cores were harvested from grafted areas and processed for histologic examination.Four implants that failed to osseointegrate were removed at the second-stage surgery (2 from a patient from group 1, and 2 from a patient from group 2). All patients were followed for at least 1 year after loading. Histologically, most of the HA particles from both groups were surrounded by newly formed bone. No statistically significant differences were found with respect to percentage of newly formed bone between the 2 groups (P = .031); however, the groups did differ significantly with respect to the percentage of residual graft material observed (P = .001).This study demonstrates that both bovine-derived and porous synthetic HA can be used successfully as graft materials for maxillary sinus augmentation. The clinical performance of the 2 materials was similar. (Clinical Trial
Immediate loading of modified acid etched dental implants in postextraction sockets: a histological and histomorphometrical comparative study in nonhuman primate Papio ursinus.
No full textImmediate loading of dental implants inserted into fresh postextraction sites has recently been proposed as a novel but challenging surgical approach. However, histological evidence and comparative data are still missing. The aim of this study was an histological and histomorphometrical comparison of submerged and immediately loaded dental implants with a new modified acid etched surface inserted into postextraction sites of nonhuman primates.Thirty-two implants were placed in postextraction sockets of 4 adult Chacma Baboons (papio ursinus). Each baboon received 8 implants: 4 submerged and 4 immediately loaded. The implants were retrieved after 90 days of healing with a 4-mm trephine bur and processed for histology and histomorphometry.The bone-to-implant contact percentage in the submerged and immediate loaded implants was 86.02\% and 86.85\%, respectively, with no statistically significant differences. In the immediately loaded implants a greater amount of ongoing remodeling was observed.Immediate loading seemed to be a valid alternative to conventional technique when a implant is inserted into postextraction sockets. Further comparative studies on a greater number of samples are necessary to confirm our findings
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
Dense hydroxyapatite inserted into postextraction sockets: a histologic and histomorphometric 20-year case report.
No full textThe biologic behavior, i.e., the degradation of hydroxyapatite (HA) in the human body, is of relevance for clinicians. The present investigation is a long-term (20-year) histologic and histomorphometric evaluation of dense HA used in postextraction sockets.Dense HA particles were used in a patient in postextraction alveolar sockets to maintain the alveolar ridge height. The patient returned after 20 years for implant treatment. A ridge remodeling was necessary during implant insertion surgery, and the HA/bone tissue was harvested with bone-cutting forceps from the canine and premolar area. The specimen was processed for histology and histomorphometry at the Implant Retrieval Centre, Dental School, University of Chieti-Pescara.Most of the particles (56\%) were surrounded partially by bone, whereas some particles (39\%) were surrounded completely. At higher magnification, bone was in close contact with the particles, and neither gaps nor fibrous tissues were present at the bone-biomaterial interface. Microscopically, the particles had a dense appearance. In only a few fields, it was possible to observe that the outer part of some particles had detached from the original particles' surface. Histomorphometry showed that bone represented 25.4\% +/- 3.2\%, marrow spaces represented 41.3\% +/- 5.2\%, and residual HA particles represented 38.1\% +/- 4.1\%.Intimate binding between bone and HA particles was present after a long-term implantation period (20 years). The fact that HA particles were surrounded closely by bone is very promising for the long-term stability of the augmentation
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
Removal of a migrated dental implant from the maxillary sinus after 7 years: a case report
No full textBACKGROUND: The accidental displacement of dental implants into the maxillary sinus is an infrequent but possible complication in dental clinical practice. The main cause of implant displacement is the inadequate bone height in the posterior maxilla. This event usually occurs during surgery, and it is more rarely reported in the post-operative period, especially with long-term follow-ups. CASE REPORT: Here, a case of an implant migrated inside the maxillary sinus at the time of abutment connection and removed 7 years later is described. DISCUSSION: Postoperative recovery was uneventful. To the author's best knowledge, this case represents the first report concerning migration of an oral implant into the maxillary sinus removed after 7 years
- …
