1,720,980 research outputs found
Surgiplanner: A new method for one step oral rehabilitation of severe atrophic maxilla
No full textThe implant-prosthetic rehabilitation of edentulous upper jaws has always been complex for surgeons and dentists. The lack of bone in both vertical and horizontal dimension does not allow the correct insertion of dental implants. In addition, patients with edentulous upper and lower arch have a loss of vertical dimension of the face and an aged expression. Many surgical techniques have been proposed to increase the bone volume, height and thickness, such as the Le Fort I osteotomy, the bone grafts and the placement of dental implants. Planning these surgical procedures is difficult, because it is not possible to reproduce the movements of osteotomized bone segments in three planes of space. This article describes the treatment of severe atrophy maxilla with a new approach using a new instrument named â Surgiplannerâ . Surgiplanner is a method that, only using a computerized axial tomography (CAT), allows to obtain a totally predetermined therapeutic result from both an aesthetic and functional point of view, with surgery of severe resorbed jaws. Surgiplanner allows repositioning of segment of the skeleton of the patientâ s face in a predetermined and controlled way for the best implant- supported oral rehabilitatio
Williams-Beuren syndrome treated with orthognathic surgery and combined partial glossectomy: Case report
Full text linkBackground Williams syndrome, also known as Williams-Beuren syndrome (WBS), is a multi-systems, congenital and rare disorder involving the cardiovascular system, connective tissue, and the central nervous system. It is a genetic disorder caused by a hemizygous microdeletion of chromosome 7q11.23. Here we report a case of WBS treated with bimaxillary osteotomies and glossectomy. Case report Orthognatic surgery was undertaken one year after the first diagnosis and the beginning of the orthodontic treatment. The maxilla was advanced at a Le Fort I of about 4 mm and was fixed with two angled plates, one on each side, applied laterally to the pyriform aperture. The lateral part of the maxilla was stabilized with wires. In addition, bilateral mandibular sagittal osteotomies were carried out together with a midline osteotomy. A partial glossectomy was performed. Intermaxillary adaptation was supported by applying soft elastics according to the concept of semi-rigid bone fixation. Two months post-surgery the occlusion was Angle class I with a well defined overbite and overjet. The healing was uneventful. Functional limitations or nerve disturbances did not occur. The miniplates remained in situ. In the case reported the "keyhole" partial glossectomy was performed in combination with the orthognatic surgery. No complication was recorded in the postoperative period and the patient had a successful outcome
Strategies for Designing 3D-Printed Titanium Plates for Orthognathic Surgery: Trade-off Between Biomechanical Compatibility and Fatigue Strength
No full textLe Fort I osteotomy is an orthognathic surgery used to correct maxillofacial deformities. The maxilla is cut and can be repositioned using patient-specific titanium fixation plates. The aim of the study is to propose a workflow that exploits the numerical modelling of orthognathic case to obtain the optimization of plate design. The 3D model of a le Fort I case was reconstructed from the patient images to create a finite element model with occlusal and muscular forces. A numerical fatigue analysis was carried out using Matake and Fatemi-Socie criteria. The plate design was optimized minimizing the plate thickness to improve biomechanical compatibility and changing the fillet radius and the thickness in critical regions for fatigue life to ensure adequate fatigue strength. The post-optimized plates show a significant increase in the predicted endurance life, reaching the required limit of 150000 chewing cycles. This work confirms the effectiveness of the optimized plate design to ensure mechanical reliability and reduce the risk of complications and discomfort for the patient
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
A NEW SYSTEM OF IMPLANT ABUTMENT CONNECTION: HOW TO IMPROVE A TWO PIECE IMPLANT SYSTEM SEALING
Full text linkPurpose. Implant dentistry has become one of the most successful dentistry techniques for replacing missing teeth. The success rate of implant dentistry is above 80%. However, peri-implantitis is a later complication of implant dentistry that if untreated, can lead to implant loss. One of the hypotized causes of peri-implantis is the bacterial leakage at the level of implant-abutment connection. Bacterial leakage is favored to the presence of a micro gap at the implant-abutment interface, allowing microorganisms to penetrate and colonize the inner part of the implant leading to biofilm accumulation and consequently to peri-implantitis development.
Materials and methods. To identify the capability of the implant to protect the internal space from the external environment, the passage of genetically modified Escherichia coli across implant-abutment interface was evaluated. Implants were immerged in a bacterial culture for twenty-four hours and then bacteria amount was measured inside implant-abutment interface with Real-time PCR.
Results. Bacteria were detected inside all studied implants, with a median percentage of 9%.
Conclusions. The reported results are better to those of previous studies carried out on different implant systems. Until now, none implant-abutment system has been proven to seal the gap between implant and abutment
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
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