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Objective: The aim of this study was to explore the methods, reporting and transparency of clinical trials in orthodontics and compare them to the field of periodontics, as a standard within dentistry., Design/setting: Cross-sectional bibliographic study., Methods: A total of 300 trials published in 2017-2018 and evenly distributed in orthodontics and periodontics were selected, assessed and analysed statistically to explore key aspects of the conduct and reporting of orthodontic clinical trials compared to trials in periodontics., Results: Several aspects are often neglected in orthodontic and periodontic trials and could be improved upon, including use of statistical expertise (22.3% of assessed trials), blinding of outcome assessors (62.3%), prospective trial registration (12.0%), adequate sample size calculation (35.7%), adherence to CONSORT (14.3%) and open data sharing (4.3%). The prevalence of statistically significant findings among orthodontic and periodontic trials was 62.3%, which was significantly associated with several methodological traits like statistician involvement (odds ratio [OR] = 0.5; 95% confidence interval [CI] = 0.3-0.9), blind outcome assessor (OR = 0.5; 95% CI = 0.2-1.0), lack of prospective trial registration (OR = 2.8; 95% CI = 1.3-5.9) and non-adherence to CONSORT (OR = 4.5; 95% CI = 1.3-15.8)., Conclusions: Although trials in orthodontics seem to be significantly worse compared to periodontics in aspects like trial registration, adherence to CONSORT and declaration of competing interests or financial support, their methods do seem to have improved considerably in recent years.

Why are there so many systematic reviews in orthodontics, and what are the negative consequences of this for our speciality as an academic discipline?

Objectives: Clinical trial registration is widely recommended because it allows tracking of trials that helps ensure full and unbiased reporting of their results. The aim of the present overview was to provide empirical evidence on bias associated with trial registration via a meta-epidemiological approach., Study Design and Settings: Six databases were searched in September 2017 for randomized clinical trials and systematic reviews thereof assessing the effects of orthodontic clinical interventions. After duplicate study selection and data extraction, statistical analysis included a two-step meta-epidemiological approach within- and across-included meta-analyses with a Paule-Mandel random-effects model to calculate differences in standardized mean differences (ΔSMD) between registered and unregistered trials and their 95% confidence intervals (CI), followed by subgroup and sensitivity analyses., Results: A total of 16 meta-analyses with 83 trials and 4,988 patients collectively were finally included, which indicated that registered trials reported less beneficial treatment effects than unregistered trials (ΔSMD = -0.36; 95% CI = -0.60, -0.12). Although some small-study effects were identified, sensitivity analyses according to precision and risk of bias indicated robustness., Conclusion: Signs of bias from lack of trial protocol registration were found with nonregistered trials reporting more beneficial intervention effects than registered ones. Caution is warranted by the interpretation of nonregistered randomized trials or systematic reviews thereof., (Copyright © 2018 Elsevier Inc. All rights reserved.)