title: Which way forward? Fixed or removable lower retainers.
abstract: OBJECTIVE
  To determine whether lower lingual, canine to canine, bonded multistrand retainers prevent relapse of lower labial segment alignment following fixed appliance therapy and to compare this with lower Hawley-type removable retainers.
  
  
  METHODS
  Two groups of 29 patients were identified. Group 1 had bonded lower canine to canine multistrand retainers placed following debonding, whereas Group 2 had lower Hawley-type retainers (with acrylic labial to the incisors) fitted following debonding. Study models were taken of all patients at debonding (T(1)) and at least 1 year post debonding (T(2)). Changes in Little's index over the study period were recorded using a reflex microscope.
  
  
  RESULTS
  Statistically significant changes in Little's index occurred in the lower labial segment of both study groups (P = .001) over the observation period. There was no statistically significant difference in the amount of change in Little's index between the bonded and removable retainer groups (P = .13). Bonded retainers tended to be placed in older patients (P = .02).
  
  
  CONCLUSIONS
  Relapse can occur in the lower labial segment with both fixed and removable retainers. The amount of relapse seen with both types of retainer is not statistically significantly different.
authors.affiliation: Bristol Dental Hospital, Bristol, UK. Nikki.Atack@bristol.ac.uk
authors.forename: Nikki
authors.initials: N
authors.lastname: Atack
authors.forename: Nigel
authors.initials: N
authors.lastname: Harradine
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Sandy
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Ireland
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000517:prevention & control* / Q000628:therapy; D018704:Orthodontic Retainers; D009971:Orthodontics, Corrective / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D055502:Secondary Prevention; D018709:Statistics, Nonparametric