This article is the result of a debate at the European Journal of Orthodontics Open Session in 2013 in Reykjavik, Iceland. The aim of this article is to highlight some of the strengths and weakness of clinical orthodontic research, with particular emphasis on randomized controlled trials (RCT). The ultimate aim of improving clinical orthodontic research in general. This article is organized into two sections with arguments for and against RCTs. The backgrounds to evidence-based evaluation and the level or quality of evidence in trials are discussed. The article emphasises what makes high quality clinical research, and gives practical advice including examples of tips and potential pitfalls for those undertaking clinical research. The overriding message is constructive and it is hoped that the article serves as an aid in evaluating, designing, conducting, and reporting clinical research.

A prospective study of 23 consecutive adult Class II division 1 malocclusion subjects (19 female and 4 male) treated with the Herbst/multibracket (MB) appliance is presented. The skeletal, dental, and facial profile changes were evaluated in addition to the mechanism of Class II correction during the Herbst phase and the settling of the occlusion during the MB phase. The mean pre-treatment age of the subjects was 21.9 years (15.7–44.4 years). Lateral head films in habitual occlusion from before treatment (T1) and after the Herbst (T2) and MB (T3) phases were analysed using standard cephalometrics and the sagittal occlusion analysis. For the standard cephalometrics, normal growth standards were utilized as control parameters. All patients were treated successfully to a Class I occlusal relationship with a normal overjet and overbite. The mandibular variables (SNB and SNPg) showed an angular increase (1.22 and 0.93 degrees, respectively) during T2–T1 followed by an angular reduction (0.40 and 0.23 degrees, respectively) during T3–T2. Compared with normal growth standards, all mandibular parameters were affected favourably by Herbst/MB treatment. Both the skeletal and soft tissue profile convexities were significantly reduced. Over the entire observation period (T3–T1), the largest amount of profile convexity reduction was seen for the soft tissue profile excluding the nose (mean 3.14 degrees). Class II correction was achieved by both skeletal and dental changes: overjet correction by 13 per cent skeletal and 87 per cent dental changes, and molar correction by 22 per cent skeletal and 78 per cent dental changes. In conclusion, on a short-term basis, the Herbst/MB appliance combination was found to be a powerful tool for non-surgical, non-extraction, treatment of Class II division I subjects in early and late adulthood.

Objective: To assess the frequency and type of upper bonded retainer failure and to identify possible predisposing factors. Materials and Methods: The records of 466 consecutive patients with upper bonded retainers were analyzed retrospectively with respect to retainer failures and failure type as well as timing of failure, differences among operators, and the number of defects of the multibracket appliances (MB) prior to the retention period. Results: A total of 58.2% of all patients experienced retainer failures. The average failure odds were 1.26 failures per retainer. The odds were highest for 3-3 retainers (1.37) and lowest for the 1-1 retainer (0.54). The detachment and total loss rates were significantly influenced by operator experience—both rates were lower for experienced practitioners. Total retainer losses occurred more frequently in case of previous MB defects, while retainer fractures were seen more frequently when the retainer included the canines. Conclusions: Upper bonded retainer failures are a frequent problem during the retention period (58.2% of patients). Less operator experience correlated with higher failure rates. An increased number of total retainer losses must also be expected with a decreasing number of bonding sites and in cases involving previous MB defects.