Early orthodontic treatment of skeletal open-bite malocclusion: a systematic review

The aim of this study was a systematic review of the literature to assess the scientific evidence on the actual outcome of early treatments of open-bite malocclusions. A literature survey was done by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to July 2004 and used the MeSH, Medical Subject Headings. The following study types that reported data on the treatment effects included: randomized clinical trials (RCT), prospective and retrospective studies with concurrent untreated as well as normal controls, and clinical trials comparing at least two treatment strategies without any untreated or normal control group involved. The search strategy resulted in 1049 articles. After selection according to the inclusionary/exclusionary criteria, seven articles qualified for the final review analysis. No RCTs of early treatment of anterior open bite have been performed. Two controlled clinical trials of early anterior open bite have been performed, and these two studies indicated the effectiveness of treatment in the mixed dentition with headgears or functional appliances (or both). Most of the studies had serious problems of lack of power because of small sample size, bias and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods. Thus, the quality level of the studies was not sufficient enough to draw any evidence-based conclusions.