1,720,970 research outputs found
Zinc plus octenidine: a new formulation for treating periodontal pathogens. A single blind study
No full textPeriodontal treatment has the aim to reduce oral infection, and prevent the progression of the disease. The potential benefits of new chemical devices for periodontal therapy, include improved patient compliance, an easier access to periodontal pocket and a lower dosage of antimicrobial agent. The objective of this study was to explore the efficacy of a chemical device containing zinc and octenidine in the treatment of chronic periodontitis in adult patients. Ten patients with a diagnosis of chronic periodontitis (20 localized chronic periodontitis sites) in the age group of 35 to 55 were selected. None of these patients received any surgical or non-surgical periodontal therapy and demonstrated radiographic evidence of moderate bone loss. The chemical device zinc plus octenedine was used by each patient after daily oral hygiene. Microbial analysis were analyzed at baseline and on the 15th day. After the treatment, a remarkable decrease in bacteria amount, both for some species and for the total count was observed in the study group. Specifically T. Forsythia and T. Denticola were eradicated whereas Total Bacteria Loading and Fusobacterium Nucleatum showed a reduction of 38% and 55%, respectively. Our study demonstrated the efficacy of the new chemical device containing zinc and octenidine in a sustained release drug delivery system in the management of moderate to severe chronic periodontitis
Genetic effect of zirconium oxide coating on osteoblast-like cells
No full textZirconium is widely used as material for prosthetic devices because its good mechanical and chemical properties. When exposed to oxygen, zirconium becomes zirconium oxide (ZrO(2)), which is biocompatible. ZrO(2) can be also prepared as a colloidal suspension and then used to coat surfaces. Zirconium oxide coating (ZrO(2)C) can potentially have specific biologic effects, and among them is bone formation related to implant osseointegration. How this biomaterial alters osteoblast activity to promote bone formation is poorly understood. We therefore attempted to address this question by using microarray techniques to identify genes that are differently regulated in osteoblasts exposed to ZrO(2)C. By using DNA microarrays containing 20,000 genes, we identified in osteoblast-like cell lines (MG-63) cultured with ZrO(2)C several genes whose expression was significantly upregulated or downregulated. The differentially expressed genes cover a broad range of functional activities: (a) cell cycle regulation, (b) signal transduction, (c) immunity, and (d) cytoskeleton component. The data reported are, to our knowledge, the first genetic portrait of ZrO(2)C effects. They can be relevant to better understand the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects
Zirconium oxide coating improves implant osseointegration in vivo.
No full textZirconium is widely used as material for prosthetic devices because of its good mechanical and chemical properties. When exposed to oxygen, zirconium becomes zirconium oxide (ZO, chemically ZrO(2)) which is biocompatible. ZO can be also prepared as a colloidal suspension and then used to coat surfaces. Zirconium oxide coating (ZOC) can potentially have specific biologic effects. The effect of ZOC on bone throughout an in vivo study using dental implants covered with ZOC and then inserted in rabbit tibia was tested in this study. The histologic analysis demonstrated that (1) bone growth is more evident around ZOC fixtures than in controls and (2) a more mature bone is present in the peri-implant ZOC surface than in controls. ZOC can enhance implant osseointegration
Silver-chlorexidine-liquid is effective to sterilize screw retaining abutment to implant space in already inserted fixture: An in vitro study
No full textContamination of screw retaining abutment to implant space (SRAIS) creates an infected room at the implant abutment junction (IAJ) that can cause or maintain peri-implantitis. Aim of the present study is to determine whether the treatment of SRAIS with silver- clorexidine liquid (named SBC-40) is able to sterilize SRAIS.
Materials and methods: A total of eight implants were used (Edierre Implant System, Edierre SpA, Genova, Italy). The SRAIS of four fixtures were firstly contaminated with 10 micro-litres of pure bacteria (i.e. genetically modified Escherichia coli). Subsequently SRAIS were treated with SBC-40 for 20 seconds and then replaced with Lysogeny Broth (LB). The remaining four implants were just filled with LB. Abutment were then screwed. All 8 fixtures were placed in tubes and immerged in LB plus E. coli to cover outer implant-abutment junction (IAJ). After 24 hours IAJ were opened and liquid collected from SRAIS by using paper tips. Same sampling was performed in LB out of implants. The tips were immerged in sterile LB and bacteria viability was determined by measuring their Optical Density (OD) at three time points.
Results: In untreated implants, bacteria grew (internally and externally) for the first 48 hours but subsequently they started to die. In treated implants, instead, bacteria grew just in the space surrounding fixtures suggesting that, even if bacteria were able to enter in SRAIS, they immediately died, thanks to the presence of SBC-40.
Conclusions: SBC-40 is potentially able to sterile the SRAIS in fixtures already inserted in patients
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
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