title: Comparison of retention characteristics of Essix and Hawley retainers.
abstract: OBJECTIVE
  We aimed to compare the retention characteristics of Essix and Hawley retainers.
  
  
  METHODS
  Adolescents undergoing fixed appliance treatment at 2 centers were recruited for this study. Twenty-two patients (16 women and 6 men) wore Essix retainers (Essix group) while 20 (14 women and 6 men) wore Hawley retainers (Hawley group). The mean retention time was 1 year, and the mean follow-up recall time for both groups was 2 years. Two qualified dental examiners evaluated the blind patient data. Maxillary and mandibular dental casts and lateral cephalograms were analyzed at 4 stages: pretreatment (T1), post-treatment (T2), post-retention (T3), and follow-up (T4).
  
  
  RESULTS
  The results revealed that Essix appliances were more efficient in retaining the anterior teeth in the mandible during a 1-year retention period. The irregularity index increased in both arches in both groups after a 2-year post-retention period. The mandibular arch lengths increased during treatment and tended to return to their original value after retention in both groups; however, these changes were statistically significant only in the Hawley group. Cephalometric variables did not show any significant differences.
  
  
  CONCLUSIONS
  The retention characteristics of both Essix and Hawley retainers are similar.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Demir
authors.forename: Hasan
authors.initials: H
authors.lastname: Babacan
authors.forename: Ruhi
authors.initials: R
authors.lastname: Nalcacı
authors.forename: Tolga
authors.initials: T
authors.lastname: Topcuoglu