Health economic evaluations in orthodontics: a systematic review

Economic evaluation is assuming increasing importance as an integral component of health services research. To conduct a systematic review of the literature and assess the evidence from studies presenting orthodontic treatment outcomes and the related costs. The literature review was conducted in four steps, according to Goodman's model, in order to identify all studies evaluating economic aspects of orthodontic interventions. The search covered the databases Medline, Cinahl, Cochrane, Embase, Google Scholar, National Health Service Economic Evaluation Database, and SCOPUS, for the period from 1966 to September 2014. The inclusion criteria were as follows: randomized controlled trials or controlled clinical trials comparing at least two different orthodontic interventions, evaluation of both economic and orthodontic outcomes, and study populations of all ages. The quality of each included study was assessed as limited, moderate, or high. The overall evidence was assessed according to the GRADE system (The Grading of Recommendations Assessment, Development and Evaluation). The applied terms for searches yielded 1838 studies, of which 989 were excluded as duplicates. Application of the inclusion and exclusion criteria identified 26 eligible studies for which the full-text versions were retrieved and scrutinized. At the final analysis, eight studies remained. Three studies were based on cost-effectiveness analyses and the other five on cost-minimization analysis. Two of the cost-minimization studies included a societal perspective, i.e. the sum of direct and indirect costs. The aims of most of the studies varied widely and of studies comparing equivalent treatment methods, few were of sufficiently high study quality. Thus, the literature to date provides an inadequate evidence base for economic aspects of orthodontic treatment. This systematic review disclosed that few orthodontic studies have presented both economic and clinical outcomes. There is currently insufficient evidence available about the health economics of orthodontic interventions. Further investigation is warranted.