Publication pattern, study design, authors and countries involved in orthodontic RCTs - a bibliometric MEDLINE survey over the past 50 years

Diversity of authors in the British Journal of Orthodontics and Journal of Orthodontics over the last 50 years

AIMS

To explore any changes in the perceived gender and affiliation of first authors of papers published in the British Journal of Orthodontics (BJO) and Journal of Orthodontics (JO), over the last 50 years.

METHODS

Electronic hand searches of the BJO and JO from 1973 to 2021, were undertaken to identify research and clinical papers published the first volume of the BJO (1973-74) and then the first two volumes of each subsequent decade i.e. 1980-81; 1990-91 to 2020-21. Articles such as Editorials, Product Updates and Abstract summaries, were excluded.The perceived gender of the first author was identified from their forename, internet sources and/or personal knowledge, where possible. The country of the first author's affiliation was identified from the author details stated in the papers. The countries were then grouped into geographical areas.

RESULTS

A total of 385 papers were identified with a steady increase from 1973 to 2021. There was a statistically significant increase in papers published by authors who were perceived to be female (odds ratio 8.33; 95% CI 4.75, 14.64). The increase in papers published by non-UK affiliated first authors was significant (odds ratio 5.01; 95% CI 2.78, 9.02).

CONCLUSIONS

The Journal has seen a significant change, over the last 50 years, in its authorship profile from nearly exclusively male, UK based authors to more than 60% of published papers having a first author who was perceived as being female and 37% originating from outside the UK.

International trends of orthodontic publications: A bibliometric observational study of the last decade (2011-2020)

INTRODUCTION

The number of published orthodontic studies has increased considerably over the past ten years.

OBJECTIVE

To analyze the bibliometric data of international orthodontic studies included in orthodontic journals encompassed by the Scopus database between 2011 and 2020, as well as to undertake data comparison between the period 2010-2015 and the period 2016-2020.

MATERIALS AND METHODS

A retrospective search was conducted on 14 orthodontic journals included in the Scopus database from 2011 to 2020. Studies of both primary and secondary types were targeted by the search. The yearly number of studies published in the 14 journals, and the first 20 countries, institutions and their type (public/private), and authors, respectively, regarding publication volume, were presented.

RESULTS

Over the past ten years, the number of publications in the chosen journals reached 9200, where the American Journal of Orthodontics and Dentofacial Orthopedics and Angle Orthodontist topped the journal list, with 22% and 12% of the publications, respectively. Furthermore, the orthodontic publication volume showed a declining trend by the end of the decade (-9%), where academic/public institutions produced most of the orthodontic studies, and the US (20%), Brazil (17%), and South Korea (8%) topped the countries with the most orthodontic studies. A comparison of the two halves of the decade revealed that orthodontic research exhibited an increasing trend in developing nations, especially Egypt (104%), Saudi Arabia (88%), and Iran (83%).

CONCLUSION

The orthodontic studies published in the chosen journals over the past ten years showed a dynamic change in yearly publication and ranking of countries, institutions, and authors.

Do longitudinal orthodontic trials use appropriate statistical analyses? A meta-epidemiological study

BACKGROUND

In orthodontic trials, longitudinal designs with multiple outcome measurements over time are common. The aim of this epidemiological study was to examine whether optimal statistical analysis approaches have been used in longitudinal orthodontic trials.

METHODS

Pubmed was searched in August 2021 for longitudinal orthodontic trials with at least three time points of outcome assessment published in the 2017-20 period. Study selection and data extraction were done independently and in duplicate. The analysis approaches undertaken were tabulated and associations between study characteristics and the use of optimal analysis or not were assessed using Fisher's exact test and logistic regression.

RESULTS

One hundred forty-seven out of 563 unique records were deemed eligible for inclusion. Only 26.50% of these trials used an optimal statistical analysis for longitudinal data where the data structure is accounted for. None of the study characteristics except the statistical significance of the results were associated with the appropriateness of the statistical analysis. The odds of significant results in studies with suboptimal analyses were higher than that in studies with optimal longitudinal analyses (odds ratio: 3.48, 95% confidence interval: 1.62, 7.46, P = 0.001). For the studies with optimal analysis, the most frequent test was repeated-measure analysis of variance (RM-ANOVA). The reporting of the statistical analysis section was suboptimal in the majority of the trials.

CONCLUSION

Most longitudinal orthodontic trials are not analysed using optimal statistical approaches. Inferences and interpretation of their results are likely to be compromised.

Relationship between European postgraduate programme accreditation and national research output: The case of the Network of Erasmus-Based European Orthodontic Postgraduate Programmes (NEBEOP) in orthodontics. A bibliometric study

AIMS

To assess in each European country the correlation between the number of Network of Erasmus-Based European Orthodontic Postgraduate Programmes (NEBEOP) members and orthodontic research activity. Secondary objectives were to describe and quantify Europe's orthodontic research.

MATERIALS AND METHODS

Articles published between 2014 and 2018 in 4 major orthodontic journals (American Journal of Orthodontics and Dentofacial Orthopedics, European Journal of Orthodontics, The Angle Orthodontist, Orthodontics and Craniofacial Research) and oral presentation abstracts of five European Orthodontic Society (EOS) congresses were analysed. For each European country, the total number of orthodontic programmes and NEBEOP memberships were collected. Descriptive statistics were performed, and Spearman correlation coefficients and risk ratios were calculated.

RESULTS

2039 articles and 261 oral presentation abstracts were included. Correlation coefficients between national number of publications, oral presentations, sum of these, all adjusted for population, and number of NEBEOP members in each country were 0.64, 0.65 and 0.62, respectively. Risk ratios were all above 1 and statistically significant for number of NEBEOP memberships per country, indicating positive associations with national orthodontic research productivity. Europe accounted for 30.5% of publications and 68.6% of oral presentations at EOS congresses during this period. European orthodontic research was not evenly distributed, since 9 countries were responsible for around 80% of the output.

CONCLUSIONS

A positive association was found between number of NEBEOP programmes and national research activity. These results could be an additional argument to support similar pan-European initiatives and guidelines for postgraduate education, not only in orthodontics but in all other dental specialties.

Class II Division 1 malocclusion treatment with extraction of maxillary first molars: Evaluation of treatment and post-treatment changes by the PAR Index

OBJECTIVE

To investigate occlusal result and post-treatment changes after orthodontic extraction of maxillary first permanent molars in patients with a Class II division 1 malocclusion.

SETTING AND SAMPLE

Retrospective longitudinal study in a private practice, with outcome evaluation by an independent academic hospital. Ninety-six patients (53 males, 43 females) consecutively treated by one orthodontist with maxillary first permanent molar extraction were studied, divided into three facial types, based on pre-treatment cephalometric values: hypodivergent (n = 18), normodivergent (n = 21) and hyperdivergent (n = 57).

METHODS

Occlusal outcome was scored on dental casts at T1 (pre-treatment), T2 (post-treatment) and T3 (mean follow-up 2.5 ± 0.9 years) using the weighted Peer Assessment Rating (PAR) Index. The paired sample t test and one-way ANOVA followed by Tukey's post hoc test were used for statistical analysis.

RESULTS

PAR was reduced by 95.7% and 89.9% at T2 and T3, respectively, compared with the start of treatment. The largest post-treatment changes were found for overjet and buccal occlusion. Linear regression analysis did not reveal a clear effect (R-Square 0.074) of age, sex, PAR score at T1, incremental PAR score T2-T1, overjet and overbite at T1, and facial type on the changes after treatment (incremental PAR score T3-T2).

CONCLUSIONS

The occlusal outcome achieved after Class II division 1 treatment with maxillary first permanent molar extractions was maintained to a large extent over a mean post-treatment follow-up of 2.5 years. Limited changes after treatment were found, for which no risk factors could be discerned.