title: Long-term follow-up of maxillary fixed retention: survival rate and periodontal health.
abstract: OBJECTIVE
  To assess the long-term success of maxillary fixed retainers, investigate their effect on gingival health, and analyse the survival rate after a mean period of 7 years (minimum 5 years) in retention.
  
  
  METHODS
  Forty one subjects were included in the study A clinical examination of the upper canine to canine region including gingival index (GI), plaque index, probing depth, and bleeding on probing (BOP) was performed. Intraoral photographs and dental impressions were taken and irregularity index was determined and compared to the values of the immediate post-therapeutic values; failures of retainers were also recorded and analysed.
  
  
  RESULTS
  The mean observed retention time was 7 years and 5 months. Irregularity index: Changes occurring during retention were statistically different between the lateral incisors bonded to retainers and the canines not bonded to retainers. Only six patients showed changes in irregularity index of the lateral incisors in spite of a retainer in place. Periodontal health: The median value of the GI for all teeth bonded to upper retainers was 1.10 and the median value of the plaque index (PI) was 1.14. PI was not a significant predictor of GI. The overall BOP of the bonded teeth to the retainer for each participant was 22.3 per cent. Failure rate: Twenty-eight out of 41 patients experienced no failure of the upper bonded retainer (68.3 per cent). Detachments were the most frequent incidents.
  
  
  CONCLUSIONS
  Although plaque accumulation might be increased in patients with already poor oral hygiene, maxillary bonded retainers caused no significant negative effects on the periodontal health.
authors.affiliation: *Department of Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland.
authors.forename: Pamela
authors.initials: P
authors.lastname: Dietrich
authors.affiliation: *Department of Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland.
authors.forename: Raphael
authors.initials: R
authors.lastname: Patcas
authors.affiliation: **Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, Medical Faculty, University of Bern, Switzerland and **Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, Medical Faculty, University of Bern, Switzerland and.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pandis
authors.affiliation: *Department of Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland theodore.eliades@zzm.uzh.ch.
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
mesh_terms: D000328:Adult; D001840:Dental Bonding / Q000009:adverse effects; D003773:Dental Plaque / Q000209:etiology; D003774:Dental Plaque Index; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D005882:Gingival Diseases / Q000209:etiology*; D006801:Humans; D008297:Male; D008437:Maxilla; D016382:Orthodontic Appliance Design; D018704:Orthodontic Retainers / Q000009:adverse effects*; D010512:Periodontal Index; D012189:Retrospective Studies; D055815:Young Adult