42 research outputs found
Author self-citation in orthodontics is associated with author origin and gender.
No full textBACKGROUND
The aims of this bibliometric study were to determine author self-citation trends in high-impact orthodontic literature and to investigate possible association between self-citation and publication characteristics.
METHODS
Six orthodontic journals with the highest impact factor as ranked by 2017 Journal Citation Reports were screened for a full publication year (2018) for original research articles, reviews, and case reports. Eligible articles were scrutinized for article and author characteristics and citation metrics. Univariable and multivariable negative binomial regression was used to examine associations between self-citation incidence and publication characteristics.
RESULTS
Medians for author self-citation rate of the most self-citing authors and self-citations were 3.03% (range 0-50) and 1 (range 0-19), respectively. In the univariable analysis, there was no association between self-citation counts and study type (P = 0.41), article topic (P = 0.61), number of authors (P = 0.62), and rank of authors (P = 0.56). Author origin (P = 0.001), gender (P = 0.001) and journal (P = 0.05) were associated with self-citation counts and in the multivariable analysis only origin and gender remained strong self-citation predictors. Asian authors and females self-cited significantly less often than all other regions and male authors.
CONCLUSIONS
Authors in orthodontics do not self-cite at a frequency that suggests potential citation manipulation. Author origin and gender were the only variables associated with citations counts. More bibliometric research is necessary to draw solid conclusions about author self-citation trends in orthodontic literature
Collaboration in orthodontic clinical trials: prevalence and association with sample size and funding
No full textAbstract Background To assess patterns of research collaboration in orthodontics and possible relationships with sample size and funding status. Methods Orthodontic randomised and non-randomised controlled clinical trials published between 2013 and 2017 were identified through electronic searching. The nature of collaboration, author institutions, study setting, sample size, and funding status were assessed. Linear and logistic regression analyses were applied. Results Of 1153 studies, 217 met the selection criteria. The majority of studies were authored by university academics (86%), were conducted in a single centre (71.9%) and in at least one university hospital (68.2%). The number of practice-based trials (10.1%), as well as the involvement of specialist practitioners (5.2%) in co-authorship, was limited. Multi-centred studies within a single country were associated with a significantly larger sample size compared to single-centred trials (P = 0.00; 95% confidence interval [CI] 33.59, 106.93). However, authorship collaboration either nationally (odds ratio [OR] 2.37; 95% CI 0.85, 6.57) or internationally across different continents (OR 5.54; 95% CI 0.62, 49.52) did not translate into increased funding. Conclusions Most orthodontic studies were undertaken in university hospital settings within a single country. Collaboration is common in orthodontics but involvement of practice settings remains limited, suggesting a need for stimulation of practice-based research and research partnerships
Some results of topological genericity
No full textWe show topological genericity for the set of functions in the space X, where
X denotes the intersection of the Hardy spaces H^p with p<1, on the open unit
disc such that the sequence of Taylor coefficients of the function and of all
derivatives of the function are unbounded. Results of similar nature are valid
when the space X is replaced by H^p(0 < p < 1) and by localized versions of
such spaces. Looking at the smaller space A(D) \subseteq H^{\infty} we show
topological genericity for the set of functions in A(D) and of all derivatives
such that the sequence of Taylor coefficients of the function are outside of
(\el)^1. We also show topological genericity for the set of functions in the
space Y, where Y denotes the intersection of the harmonic Hardy spaces h^p with
p 0)Comment: arXiv admin note: text overlap with arXiv:2105.07818 by other author
Appropriateness of reporting statistical results in orthodontics: The dominance of P values over confidence intervals
No full textThe purpose of this study was to search the orthodontic literature and determine the frequency of reporting of confidence intervals (CIs) in orthodontic journals with an impact factor. The six latest issues of the American Journal of Orthodontics and Dentofacial Orthopedics, the European Journal of Orthodontics, and the Angle Orthodontist were hand searched and the reporting of CIs, P values, and implementation of univariate or multivariate statistical analyses were recorded. Additionally, studies were classified according to the type/design as cross-sectional, case-control, cohort, and clinical trials, and according to the subject of the study as growth/genetics, behaviour/psychology, diagnosis/treatment, and biomaterials/biomechanics. The data were analyzed using descriptive statistics followed by univariate examination of statistical associations, logistic regression, and multivariate modelling.CI reporting was very limited and was recorded in only 6 per cent of the included published studies. CI reporting was independent of journal, study area, and design. Studies that used multivariate statistical analyses had a higher probability of reporting CIs compared with those using univariate statistical analyses. Misunderstanding of the use of P values and CIs may have important implications in implementation of research findings in clinical practice. © The Author 2010. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved
Publication rate of abstracts from presentations at the British Orthodontic Conference 2009-2014.
No full textOBJECTIVE
The primary objective of this study was to investigate the publication rate of scientific abstracts presented at the British Orthodontic Conference 2009-2014. Predictors of full-text publications after presentation of abstracts were explored.
DESIGN
Cross-sectional study.
MATERIALS AND METHODS
Details of abstracts were retrieved from the conference programmes. Abstracts were screened and full-text publications identified by a single author with discrepancies discussed. Two electronic databases were searched to identify full-text publication of abstracts presented at the British Orthodontic Conference during 2009-2014. Study characteristics were recorded in a prespecified data collection sheet. Descriptive and correlation statistics were calculated. Multivariable Cox regression modelling was implemented in order to assess the effect of predictors on the instance of probability of publication.
RESULTS
A total of 225 abstracts (148 poster presentations and 77 oral presentations) were identified. Observational studies were frequent (60%) and significant results were reported in 38.7% of abstracts. The rate of full-text publication after abstract presentation was 46.2% with a mean time to publication of 18.3 ± 18.7 months. Authors based at both university and hospitals (Hazard ratio: 2.63, 95% confidence interval [CI] 1.26-5.47, P=0.01) had a higher instant probability of publication compared to university only, whereas diagnostic studies (Hazard ratio: 0.18, 95% CI 0.04-0.74, P=0.02) had lower instant probability of publication compared to systematic reviews.
CONCLUSION
Over 50% of study abstracts presented at the British Orthodontic Conference during 2009-2014 remain unpublished. Author affiliation and study type appear to influence full text publication. In order to reduce publication bias within the literature, publication of full-text articles by authors of presented abstracts is encouraged
Are longitudinal randomised controlled oral health trials properly analysed? A meta-epidemiological study.
No full textINTRODUCTION
Longitudinal designs with multiple outcome measurements are commonly encountered in oral health randomised controlled trials (RCTs). The aim of this meta epidemiological study was to assess whether optimal statistical analysis approaches have been used in longitudinal oral health RCTs.
DATA SOURCES
PubMed search was undertaken in September 2021 for longitudinal oral health RCTs with at least 3 repeated outcome measurements which have been published between 2016- 2020 in the highest impact general and specialty dental journals.
STUDY SELECTION
Study selection and data extraction were accomplished independently and in duplicate. The statistical methods undertaken in the selected articles were tabulated, and the association between study characteristics and use of optimal analyses were assessed using X2 or Fisher's exact test and logistic regression.
RESULTS
Five hundred and five oral health RCTs were deemed eligible for inclusion. Of these, only 28.3% RCTs used optimal statistical analyses for a longitudinal trial design. For the trials with an optimal statistical approach, the most frequent test used was repeated measures analysis of variance (RM-ANOVA) followed by mixed effect models (MEM). The use of optimal statistical tests was predicated by the involvement of a statistician (OR: 2, 95% CI:1.27 - 3.18, p<0.01), the journal impact factor (OR:1.19, 95% CI;1.1 - 1.29), continent of first author (likelihood ratio test p=0.01), number of the authors (OR:1.22, 95% CI;1.12-1.3, p<0.001), protocol registration (OR: 1.48, 95%CI; 1 to 2.2, p=0.05), funding(OR:2.4, 95%CI; 1.6 - 3.7, p<0.001), and dental specialty (likelihood ratio test p<0.001).
CONCLUSIONS
Most longitudinal oral health RCTs did not use optimal statistical analyses. Greater awareness of optimal analyses used to assess longitudinal data reported in oral health trials is required to circumvent the reporting of suboptimal inferences, selective reporting and research waste.
CLINICAL SIGNIFICANCE
Further progress is required to avoid suboptimal statistical analyses and fully utilise the benefits of the repeated measurements over time in oral health RCTs
Δύναμη στην άρση μπάρας στους μηρούς και επίδοση στο επολέ της άρσης βαρών
No full textΣκοπός της παρούσας εργασίας είναι η πειραματική διερεύνηση της συσχέτισης μεταξύ της μέγιστης δύναμης στην άρση της μπάρας στους μηρούς (deadlift) και της επίδοσης στη κίνηση επολέ (clean) της Άρσης Βαρών. Δεκαέξι προπτυχιακοί φοιτητές φυσικής αγωγής ειδικευόμενοι στο άθλημα της Ολυμπιακής Άρσης Βαρών συμμετείχαν σε αυτή τη μελέτη (n=16, ηλικία: 25 ± 7 χρόνια, σωματικό βάρος: 73 ± 12 κιλά, ύψος: 174 ± 9 εκατοστά). Τα ανθρωπομετρικά χαρακτηριστικά μετρήθηκαν μέσω μηχανήματος DEXA scan στο εργαστήριο Μυϊκής Ενδυνάμωσης του Τμήματος Επιστήμης Φυσικής Αγωγής και Αθλητισμού (ΤΕΦΑΑ) ενώ οι μετρήσεις της επίδοσης μίας μέγιστης επανάληψης (1 ΜΕ) στην άρση μπάρας στους μηρούς και στην κίνηση επολέ της Άρσης Βαρών πραγματοποιήθηκαν στις προπονητικές εγκαταστάσεις του Σταδίου Ειρήνης και Φιλίας (ΣΕΦ), όπου και πραγματοποιούν την προπόνηση τους οι φοιτητές. Τα αποτελέσματα της στατιστικής ανάλυσης έδειξαν σχεδόν τέλεια γραμμική συσχέτιση (r=0,94, p=0,05) ανάμεσα στη μέγιστη δύναμη στην άρση μπάρας στους μηρούς (deadlift) και στην επίδοση στο επολέ (clean). Τα αποτελέσματα αυτά υποδεικνύουν ότι η άσκηση της άρσης μπάρας στους μηρούς μπορεί να αποτελέσει προγνωστικό παράγοντα της επίδοσης στο επολέ σε τεχνικά καταρτισμένους αθλητές/αθλούμενους στην Άρση Βαρών. Επιπρόσθετα, η άρση μπάρας στους μηρούς μπορεί να αποτελέσει ένα ισχυρό προπονητικό εργαλείο.ΟΧ
Citation of prior systematic reviews in reports of randomized controlled trials published in dental speciality journals.
No full textOBJECTIVES
To assess the extent to which reports of dental Randomised Clinical Trials (RCTs) cite prior systematic reviews (SR) to explain the rationale or justification of the trial. Study characteristics that predicated the citation of SR in the RCT report were explored.
METHODS
An electronic database search was undertaken to identify dental RCTs published between 1st January 2014 and 31st December 2019. All titles and abstracts were screened independently by two authors. Descriptive statistics and associations were calculated for the study characteristics. Logistic regression was used to identify predicators of SR inclusion in the trial report.
RESULTS
682 RCTs were analysed. 312 SRs were available of which 62.5 % were cited and 37.5 % were not included but were available in the literature within 12 months of trial commencement. An association between inclusion of SR and trial registration (P = 0.046) was detected. For the inclusion of a SR, authors based in Asia or other had lower odds than those based in Europe (OR: 0.53; 95 % CI:0.34,0.82; p = 0.005). Every unit increase in journal impact factor increased the odds of SR inclusion (OR: 1.23; 95 %: 1.06, 1.43; p = 0.006).
CONCLUSIONS
A relatively high proportion of dental RCTs (37.5 %) did not cite a SR in the introduction section to justify the rationale of the trial when a relevant SR was available. Trials conducted by a corresponding author based in Europe and published in journals with an increasing impact factor were also more likely to cite a SR.
CLINICAL SIGNIFICANCE
Further progress is required to minimise research waste and ensure resources are channelled towards clinically useful trials which have an appropriate rationale and justification
Reporting of the methodological quality of search strategies in orthodontic quantitative systematic reviews.
No full textBACKGROUND
This study aimed to assess the reporting of the methodological quality of search strategies undertaken in orthodontic quantitative systematic reviews (SRs) and hence their reproducibility.
MATERIALS AND METHODS
A search of a single electronic database (Medline via PubMed) was undertaken to identify interventional orthodontic SRs with meta-analysis published within a 10-year period. The Cochrane Library of Systematic Reviews was also sourced. Full articles were reviewed by two assessors against the eligibility criteria. The reporting quality of each search strategy was assessed using a previously validated checklist with a score of 1 or 2 given for each of the eight items. Cumulative totals were calculated. Guided by previous research, the authors agreed the following cut-offs to categorize the overall level of quality: 8-10 (poor), 10-12 (fair), and greater than 13 (good).
RESULTS
A total of 127 SRs were analysed. The overall median quality score for the reporting of the search strategy was 14 [interquartile range (IQR): 13-15]. Cochrane SRs and those originating in Europe received higher aggregate scores, whereas no difference was evident based on Prospero registration. The continent of the corresponding author predicated the overall score. Non-Cochrane reviews achieved lower overall scores compared to Cochrane reviews (-1.0, 95% confidence interval: -1.65, -0.34, P = 0.003). The most frequently searched database was EMBASE (N = 93) and the median number of authors was 5 (IQR 4-6). Authors of 26.8% of SRs searched the grey literature. Language restrictions were applied to the search strategies of 88 (69.3%) SRs.
CONCLUSIONS
The reporting quality of search strategies undertaken in orthodontic SRs is at a good level but differences between Cochrane and non-Cochrane reviews currently exist. The reporting of searching of the grey literature and application of no language restrictions can be improved
Most recommended medical interventions reach P < 0.005 for their primary outcomes in meta-analyses
No full textBackground: It has been proposed that the threshold of statistical significance should shift from P-value<0.05 to P-value<0.005, but there is concern that this move may dismiss effective, useful interventions. We aimed to assess how often medical interventions are recommended although their evidence in meta-analyses of randomized trials lies between P-value=0.05 and P-value=0.005. Methods: We included Cochrane systematic reviews (SRs) published from 1 January 2013 to 30 June 2014 that had at least one meta-analysis with GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessment and at least one primary outcome having favourable results for efficacy at P-value<0.05. Only comparisons of randomized trials between active versus no treatment/placebo were included. We then assessed the respective UpToDate recommendations for clinical practice from 22 May 2018 to 5 October 2018 and recorded how many treatments were recommended and what were the P-values in their meta-analysis evidence. The primary analysis was based on the first-listed outcomes. Results: Of 608 screened SRs with GRADE assessment, 113 SRs were eligible, including 143 comparisons of which 128 comparisons had first-listed primary outcomes with UpToDate coverage. Altogether, 60% (58/97) of interventions with P-values<0.005 for their evidence were recommended versus 32% (10/31) of those with P-value 0.005-0.05. Therefore, most (58/68, 85.2%) of the recommended interventions had P-values<0.005 for the first-listed primary outcome. Of the 10 exceptions, 4 had other primary outcomes with P-values<0.005 and another 4 had additional extensive evidence for similar indications that would allow extrapolation for practice recommendations. Conclusions: Few interventions are recommended without their evidence from metaanalyses of randomized trials reaching P-value<0.005. © The Author(s) 2019
