1,720,958 research outputs found
In-vitro comparison of toothbrush bristles penetration into the peri-implant sulcus
No full textBackground: Implant-prosthetic reconstructions present anatomical and structural characteristics different from the dento-periodontal condition. These differences can lead to a problematic hygienic access by toothbrush bristles and a consequently reduced biofilm removal.
Aim/Hypothesis: The aim of this preclinical study was to compare the ability of the conical and cylindrical bristles to penetrate the peri-implant sulcus.
Material and Methods: A mandibular dentition was reproduced using a plaster model: the gingival component was recreated in silicone and a glass cylinder was positioned simulating a 4 mm diameter implant. The penetration of the bristles during brushing was recorded by using an optical fiber placed inside the cylinder. The Bass Technique was performed in a humid environment from the vestibular side. This brushing motion is described as a vibratory movement of the bristles oriented at 45° respect to the long axis of the tooth into the sulcus. The protocol included 5 toothbrushes per group and 10 tests per toothbrush, for a total of 50 assessments for each of the two groups. Each test lasted 1 minute with controlled pressure of approximately 350gr and a stroke length of 25 mm. Five degrees of penetration were identified: grade 0 (<2 mm), grade 1 (2–3 mm), grade 2 (3–4 mm), grade 3 (4–5 mm) and grade 4 (5–8 mm). The highest value was collected for each test.
Results: The conical bristles showed 8 times greater efficacy (P = 0.001) than the cylindrical bristles (multilevel analysis). The percentage of tests reaching depths ≥3 mm was 86% for conical group and 28% for the cylindrical group.
Conclusion and Clinical implications: This preclinical study shows a clear and superior penetration capacity of the conical bristles compared to traditional cylindrical ones. Further studies are required to investigate the correlation between penetrative capacity and cleaning efficacy in implant conditions. If a greater penetrative capacity is correlated with a greater cleaning efficacy, then these newly designed bristles would be preferable
In vitro comparison of two types of toothbrush bristles in penetration capacity into the peri- implant sulcus.
No full textAim: The aim of this preclinical study was to compare the ability of the conical and cylindrical bristles to penetrate the peri-implant sulcus.
Methods: A mandibular dentition was reproduced using a plaster model. The gingival component was recreated in silicone and a glass cylinder simulating a 4mm diameter implant was positioned by replacing element # 3.6. Using an 1mm diameter optical fiber placed from the lingual side inside the cylinder, the penetration of the bristles was recorded during the brushing. The Bass Technique was performed in a humid environment from the vestibular side. This brushing motion is described as a vibratory movement of the bristles arranged at 45° respect to the long axis of the tooth into the sulcus. The protocol included 5 toothbrushes per group and 10 tests per toothbrush for a total of 50 assessments per group. Each test lasted 1 minute with controlled pressure of approximately 500gr and a stroke length of 15 mm. From the video clips acquired, 4 degrees of penetration were identified: grade 0 (<2mm), grade 1 (2-3mm), grade 2 (3-4mm), grade 3 (4-5mm) and grade 4 (5-8mm). The highest value was collected for each test. At an α level of 0.05 for a one-tailed test with a power of 80% and a margin of superiority of 40%, a sample of 10 toothbrushes was needed. Intraoperative variability was assessed with the Cohen's kappa coefficient. A generalized mixed-effect linear model (multilevel analysis) was used considering the level of bristle penetration as the primary outcome and the type of bristle as fixed effects. The level of significance α was a priori set at 0.05. The null hypothesis affirms that no difference of efficacy (level of penetration) exists between the two types of bristles.
Results: Excellent agreement was obtained between the measurement performed by the examiner (K-statistics =1). The conical bristles showed 8 times greater efficacy (p = 0.001) than the cylindrical bristles; moreover, with respect to the latter, the degree of penetration of the conical bristles proved to be 2 times (p = 0.015), 20 times (p = 0.001) and 76 times (p = 0.001) higher than degrees 1, 2 and 3 respectively. The null hypothesis was therefore rejected.
Conclusion: This preclinical study shows a clear and superior penetration capacity of the conical bristles compared to traditional cylindrical ones. This result suggests a greater hygienic efficacy at the peri- implant level for the newly designed bristles
In-vitro comparison of two different toothbrush bristles about peri-implant sulcus penetration
Full text linkObjective: The aim of this preclinical study was to compare the ability of tapered and cylindrical bristles to penetrate the peri-implant sulcus. Methods: A full mandibular dental arch was reproduced in plaster cast. In site #3.6 a hollow glass cylinder was positioned simulating a 4 mm diameter implant and the gingival component was recreated by using dedicated silicone. A Bass brushing technique was performed from the vestibular side in humid environment. During it, the penetration of the bristles between the gum and the implant was recorded by mean of an optic fibre fixed inside the cylinder. The protocol included 5 toothbrushes per group and 10 tests per toothbrush, for a total of 50 assessments for each of the two groups. A scale of 5 grades for bristle penetration was defined: grade 0 (× < 2 mm), grade 1 (2 ≤ × < 3 mm), grade 2 (3 ≤ × < 4 mm), grade 3 (4 ≤ × < 5 mm) and grade 4 (5 ≤ × < 8 mm). From the video recordings the highest value of penetration was identified for each test. Results: The tapered bristles showed an 8 times greater penetration capacity (p = 0.001) in respect to the cylindrical bristles (multilevel analysis). The percentage of tests reaching depths ≥3 mm was 86% for tapered group and 28% for the cylindrical group. Conclusion: This preclinical study shows a clear and superior penetration capacity of the tapered bristles in respect to traditional cylindrical ones. For tapered bristles, a potentially greater hygienic efficacy around dental implants is suggested
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
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
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