title: Systematic reviews in orthodontics: what have we learned?
abstract: The literature is becoming replete with systematic reviews of orthodontic-related topics. However, their findings have not been appraised and summarised collectively.
  
  
  METHODS
  Systematic reviews related to orthodontics published between 1 January 2000, and 31 January 2007 were identified and reviewed.
  
  
  RESULTS
  Fifty-one orthodontic systematic reviews were identified in the defined period. A highly significant percentage of reviews (29%) failed to reach conclusions. Conclusions were made in the remaining reviews although many relied on secondary levels of evidence to do so. In this narrative review the findings from these studies are summarised.
  
  
  CONCLUSIONS
  Systematic reviews in orthodontic-related areas have produced some interesting findings. However an unacceptably high number continue to be inconclusive, reflecting methodological inadequacies of the review process and exposing inadequacies in our evidence base.
authors: Maxillofacial Unit, Kent and Canterbury Hospital, Kent, UK.
authors: P S
authors: PS
authors: Fleming
authors: A T
authors: AT
authors: DiBiase
mesh_terms: D006801:Humans; D015201:Meta-Analysis as Topic; D009970:Orthodontics; D012196:Review Literature as Topic