title: Effectiveness of lingual retainers bonded to the canines in preventing mandibular incisor relapse.
abstract: BACKGROUND
  A retainer bonded to the lingual surfaces of the mandibular canines (3-3 retainer) is a widely used type of retention. Our aim in this study was to assess the effectiveness of the 3-3 mandibular lingual stainless steel retainer to prevent relapse of the orthodontic treatment in the mandibular anterior region.
  
  
  METHODS
  The sample consisted of the dental casts of 235 consecutively treated patients (96 boys, 139 girls) from the archives of the Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Center, The Netherlands, who received a 3-3 mandibular lingual stainless steel retainer at the end of active orthodontic treatment. The casts were studied before treatment (Ts), immediately after treatment (T0), and 2 years (T2), and 5 years (T5) posttreatment.
  
  
  RESULTS
  The main irregularity index decreased significantly from 7.2 mm (SD, 4.0) at Ts to 0.3 mm (SD, 0.5) at T0; it increased significantly during the posttreatment period to 0.7 mm (SD, 0.8) at T2 and 0.9 mm (SD, 0.9) at T5. The irregularity index was stable during the 5-year posttreatment period (T0-T5) in 141 patients (60%) and increased by 0.4 mm (SD, 0.7) in 94 patients (40%). The intercanine distance increased 1.3 mm between Ts and T0 and remained stable during the posttreatment period.
  
  
  CONCLUSIONS
  The 3-3 mandibular lingual stainless steel retainer (bonded to the canines only) is effective in preventing relapse in the mandibular anterior region in most patients, but a relatively high percentage will experience a small to moderate increase in mandibular incisor irregularity.
authors.affiliation: Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Renkema
authors.forename: Samah
authors.initials: S
authors.lastname: Al-Assad
authors.forename: Ewald
authors.initials: E
authors.lastname: Bronkhorst
authors.forename: Sabine
authors.initials: S
authors.lastname: Weindel
authors.forename: Christos
authors.initials: C
authors.lastname: Katsaros
authors.forename: Jörg A
authors.initials: JA
authors.lastname: Lisson
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003481:Cuspid; D000044:Dental Abutments; D001840:Dental Bonding; D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000503:physiopathology*; D008297:Male; D008310:Malocclusion / Q000145:classification / Q000628:therapy*; D008334:Mandible; D009811:Odontometry; D016382:Orthodontic Appliance Design / Q000295:instrumentation*; D018704:Orthodontic Retainers / Q000145:classification; D009969:Orthodontic Wires; D012189:Retrospective Studies; D055502:Secondary Prevention; D013997:Time Factors; D014085:Tooth Migration / Q000517:prevention & control*; D017211:Treatment Failure