1,720,991 research outputs found
Effects of local administration of ketorolac tromethamine, a nonsteroidal anti-inflammatory drug, on orthodontic tooth movement in rats
Full text linkTooth movement rates can be inhibited by prostaglandin inhibitors acting systemically. We investigated the locally delivered effects of ketorolac tromethamine (KT), a potent nonsteroidal anti-inflammatory drug (NSAID), on orthodontic tooth movements in twelve Wistar rats. U-shaped expansion springs were positioned between upper first molars exerting equal and reciprocal, laterally directed forces for seventeen days. Every fourth day 1.5 mg of KT in solution was delivered around one molar and saline solution was injected adjacent to the contralateral molar. Subsequent to a wash-out period lasting fifteen days of continued expansion, the appliances were removed, the teeth allowed to relapse for thirteen days while the same schedule was maintained for the NSAID delivery. Combining the data from all the teeth that received KT and comparing those with the control data, no significant differences were seen with their movements during the expansion or relapse phases
Recorded interactive seminars in orthodontic distance education
Full text linkIncreasing internet speeds at a time of orthodontic faculty shortages has made distance learning a viable supplement to orthodontic education. Previous investigation with orthodontic residents has shown viewing a recording of a small group seminar and having short follow-up discussion is almost as effective and acceptable as participating live and interactive from a distance, requiring less equipment, reducing necessary Internet speeds, and adding flexibility for residents and faculty. Internet based libraries of recordings may also offer private practitioners an alternative to traditional continuing education. We investigated the effectiveness and acceptability of using interactive seminar recordings and follow-up discussion in orthodontic education with both residents and private practitioners. In a series of three papers, we conclude that this type of learning experience is well accepted by both residents and private practitioners. Also, recordings and follow-up discussion appears as effective as being live and interactive, both locally and from a distance
Airway Volume and Shape from Cone-Beam CT: Relationship to Facial Morphology
Full text linkCone beam computed tomography (CBCT) records of 62 non-growing patients were used to evaluate the pharyngeal airway volume (upper and lower components), and the shape of the airway, using semi-automatic segmentations to calculate real volumes instead of estimates based on linear measurements. The sample was divided according to anteroposterior jaw relationships and vertical proportions. There was a statistically significant relationship between the volume of the lower component and a-p jaw relationship, and between airway volume and both the size of the face and gender. No differences in airway volumes related to vertical facial proportions were observed. Skeletal Class II patients tended to display forward inclination of the airway, greater projection of the tongue into the airway, and narrower airways. Skeletal Class III patients usually had a vertically-oriented airway. This study is a pioneer in measuring real 3-D models and controlling for face size
Interactive distance learning in post-doctoral orthodontic education
Full text linkA series of research projects at the University of North Carolina - Chapel Hill (UNC) have been dedicated to determining the best way to provide distance education to graduate orthodontic programs. Data from early studies by Bednar and Miller et al, determined the most effective and acceptable method for distance learning in post-graduate orthodontic programs was a "blended" experience. This blended approach combines self-preparation through reading assigned articles, watching a recording of an actual interactive seminar on a designated website, and follow up discussion with faculty (either live or distant). In 2008, a grant from the American Association of Orthodontists made it possible to open this experience to all 63 programs in the United States. This master's thesis consists of two papers: Paper I evaluates the utilization and acceptability of interactive distance learning for orthodontic residents; Paper II investigates problems with interactive distance learning in post-doctoral education and identifies potential solutions
Application of Distance Learning to Interactive Seminar Instruction in Orthodontic Residency Programs
Full text linkA series of experiments involving 3 orthodontic departments has shown that distance learning can be acceptable to residents and effective in teaching concepts that are fundamental to orthodontic practice. The improvement from pre- to post-test scores after observing a sequence of distance seminars was similar to direct instruction. Orthodontic residents rated the educational experiences very positively. Live participation in seminars via video conferencing was preferred to live observation or later observation of a recording, but observation provided similar improvement in test scores. The acceptability of the distance seminars appeared to be influenced by the instructor's personality and teaching style in facilitating interaction, the seminar subject, the residents' comfort level in dealing with this technology, and the sequence for interaction vs observation. Further development of recorded seminars with live follow-up discussions has the potential to supplement instruction in graduate orthodontic programs and help with the impending shortage of experienced fulltime orthodontic faculty
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
A Contemporary Perspective on Tooth Extraction in Orthodontics
Full text linkIntroduction: The decision to extract teeth for orthodontic purposes is one of the most complex and debated topics in the specialty. The profession's understanding of factors affecting the extraction decision (e.g., outcome stability and facial appearance) has evolved over time, and estimated extraction rates have varied from 10% in 1953 to 78% in 1968 to 28% in 1994. A contemporary perspective on the rate of orthodontic extractions is needed to help clinicians understand this treatment choice in light of 21st century philosophies, techniques, and appliances. To this end, we investigated changes in orthodontic extraction rates at the University of North Carolina from 2000 to 2011, as well as factors that may have affected those rates. We hypothesize that extraction rates have changed as a result of evolving diagnostic methodology and appliance selection (e.g., self-ligating brackets). Methods: Pre- and post- treatment records were analyzed to determine extraction rates over time, and different factors (Angle classification, skeletal relationship, use of self-ligation, etc.) were investigated to evaluate potential impact on the extraction decision. The sample consisted of 2,184 patients, with 1,263 females (58%). Age at the start of treatment ranged from 7 to 67 years. Third molar extractions were excluded from analyses. Student t-test and chi square were used to evaluate the extraction rate over time. Logistic regression was used to investigate diagnostic and treatment factors that might affect extraction rates over time. Results: The extraction rate decreased significantly from 2000 to 2005, from 40% to less than 20%. After 2005, it remained stable around 27%. 8 out of our 13 explanatory variables were found to influence the overall extraction rate but none of them could explain the decrease of the extraction rate over time. Conclusions: The extraction rate fluctuated greatly since 2000 and has decreased linearly over the years (p<0.05). Several explanatory variables were found to influence the overall extraction decision, but none of them could explain the decreasing trend over time. Irrational cognition with medical concerns about extraction may have an impact on the decreased trend.Master of Scienc
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