title: Failure of fixed orthodontic retainers: A systematic review.
abstract: OBJECTIVE
  To evaluate the risk of failure of fixed orthodontic retention protocols.
  
  
  METHODS
  Screening for inclusion eligibility, quality assessment of studies and data extraction was performed independently by two authors.
  
  
  METHODS
  The electronic databases MEDLINE, EMBASE and CENTRAL were searched with no restrictions on publication date or language using detailed strategies. The main outcome assessed was bond failure.
  
  
  METHODS
  Twenty-seven studies satisfied the inclusion criteria. Randomised controlled trials and prospective studies were evaluated according to the Cochrane risk of bias tool. Retrospective studies were graded employing the predetermined criteria of Bondemark.
  
  
  RESULTS
  Nine randomised controlled trials, four of which were of low quality, were identified. Six studies had a prospective design and all were of low quality. Twelve studies were retrospective. The quality of trial reporting was poor in general. Four studies assessing glass-fibre retainers, three RCTs and one prospective, reported bond failures from 11 to 71%, whereas twenty studies evaluating multistranded retainers – nine RCTs, two prospective and nine retrospective – reported failures ranging from 12 to 50%. One comparison was performed, multistranded wires vs. polyehtylene woven ribbon (RR: 1.74; 95% CI: 0.45, 6.73; p=0.42).
  
  
  CONCLUSIONS
  The quality of the available evidence is low. No conclusive evidence was found in order to guide orthodontists in the selection of the best protocol.
  
  
  CONCLUSIONS
  Although fixed orthodontic retainers have been used for years in clinical practice, the selection of the best treatment protocol still remains a subjective issue. The available studies, and their synthesis, cannot provide reliable evidence in this field.
authors.affiliation: Department of Orthodontics, University of Athens, 2 Thivon Str, 11527 Athens, Greece. Electronic address: annaeliades@gmail.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Iliadi
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. Electronic address: dimitrios.kloukos@zmk.unibe.ch.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kloukos
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. Electronic address: nikosgant@yahoo.gr.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Gkantidis
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. Electronic address: christos.katsaros@zmk.unibe.ch.
authors.forename: Christos
authors.initials: C
authors.lastname: Katsaros
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. Electronic address: npandis@yahoo.com.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pandis
mesh_terms: D004868:Equipment Failure; D006801:Humans; D018704:Orthodontic Retainers; D009970:Orthodontics / Q000295:instrumentation*
keywords: Bond failure; Detachment; Fixed retainers; Orthodontic retention