title: Vacuum-formed retainers more effective than Hawley retainers.
abstract: METHODS
  A randomised controlled trial (RCT) was performed in a single orthodontic practice.
  
  
  METHODS
  The aim was to compare the clinical effectiveness of Hawley and vacuum-formed retainers (VFR) over a 6-month period of retention. Three hundred and ninety-seven patients were treated by a specialist orthodontist and randomly allocated to wear either Hawley retainers (n=196) or VFR (n=201).
  
  
  METHODS
  A blinded examiner analysed the records of maxillary and mandibular dental casts at debond and at 6 months into retention, assessing tooth rotation mesial to the first permanent molar, intercanine and intermolar widths, and Little's Index of Irregularity.
  
  
  RESULTS
  Three hundred and fifty-five individuals participated through to the conclusion of the trial, giving a completion rate of 89%. The results showed significantly greater changes in irregularity of the incisors in the Hawley group than in the VFR group at 6 months.
  
  
  CONCLUSIONS
  VRF are more effective than Hawley retainers at holding the correction of the maxillary and mandibular labial segments.
authors: Orthodontist, Sydney, Australia.
authors: Jan
authors: J
authors: Ledvinka