title: A comparison of the efficacy of fixed versus removable functional appliances in children with Class II malocclusion: A systematic review.
abstract: To systematically compare the efficacy of fixed and removable functional appliances in Class II malocclusion in terms of morphological and patient-centred outcomes.
  
  
  
  A comprehensive search of electronic databases without language or time restrictions was undertaken, applying a pre-specified search strategy. Supplementary electronic searching of orthodontics journals and references list of included studies was performed.
  
  
  
  Randomized (RCTs) and controlled (CCTs) clinical trials involving children under 16 years with Class II malocclusion and overjet more than 5mm were included.
  
  
  
  A range of clinician- and patient-centred outcomes were evaluated and compared. Risk of bias assessment was carried out using the Cochrane Collaboration tool.
  
  
  
  Only four clinical trials were found to meet our criteria, of which two were RCTs, comparing the Herbst and the Twin Block appliances. Two further CCTs, compared the Activator to the Forsus and the Twin Force Bite Corrector, respectively. One study was assessed to be at unclear and the remaining at high risk of bias, precluding meta-analysis. There was also significant clinical heterogeneity in terms of methodology, type of intervention and the measured outcomes. Both modalities were effective in correcting the overjet with little differences found in cephalometric changes and a shortage of data concerning patient-centred outcomes.
  
  
  
  There is little evidence concerning the relative effectiveness of fixed and functional appliances or in relation to patient experiences and perceptions of these treatment modalities. Further well-designed clinical trials assessing the relative merits of both clinician- and patient-centred outcomes are needed.
authors.affiliation: Oral Growth and Development, Institute of Dentistry, Queen Mary University of London, London, UK.
authors.forename: Moaiyad Moussa
authors.initials: MM
authors.lastname: Pacha
authors.affiliation: Oral Growth and Development, Institute of Dentistry, Queen Mary University of London, London, UK.
authors.forename: Padhraig S
authors.initials: PS
authors.lastname: Fleming
authors.affiliation: Oral Growth and Development, Institute of Dentistry, Queen Mary University of London, London, UK a.s.johal@qmul.ac.uk.
authors.forename: Ama
authors.initials: A
authors.lastname: Johal
mesh_terms: D002508:Cephalometry; D002648:Child; D006801:Humans; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D017289:Orthodontic Appliances, Functional; D009968:Orthodontic Appliances, Removable; D017063:Outcome Assessment, Health Care; D057887:Overbite / Q000628:therapy; D063868:Patient Outcome Assessment