Stability of Maxillary Anterior Teeth After Two Years of Retention in Adolescents Comparing Two Bonded and a Vacuum-formed Retainer
Condition: Orthodontic Appliance Complication
Study type: Interventional

Summary: 
      After orthodontic treatment 3 different retention devices will be compared.Thirty patients in
      each group; Group 1) Bonded retainer 13-23, Group 2)Bonded retainer 12-22 and Group 3)
      Vacuum-formed retainer covering all erupted teeth in the maxilla. Retention capacity between
      these three devices will be compared after 2 years of retention by measuring Contact Point
      displacements (CPD) between 6 anterior teeth and sum of 5 anterior CPDs called Little´s
      Irregularity Index (LII).
    

Detailed description: 
      Studies have shown that esthetics, no doubt, is the major motivating factor for orthodontic
      treatment both in adults and adolescents.Orthodontic relapses are usually described as
      changes toward the pretreatment status. These changes occur very fast if the teeth are not
      kept in their new position. That is the reason why, after orthodontic treatment, the result
      must be stabilized by some kind of retention device to prevent relapse. However, after this
      first period of remodeling of periodontal structures, comes the later period of changes.

      Relapse in aesthetic zone (Anterior teeth), is the major reason why patients are dissatisfied
      with the results and seek for retreatment. There is a gap in our knowledge which kind of
      retention device is more effective to stabilize achieved alignment after orthodontic
      treatment.

      This randomized clinical trial, tries to answer to that question. The investigators shall
      compare three different retention devices and measure changes after 2 years when retention
      devices have been in place and later compare the long-term results when the retainers have
      been removed after 2 years of retention (future study 5 years ptstretention).

      Randomization Three months before the estimated removal of the fixed appliances, the patients
      will be invited to take part in the trial. After gaining informed consent from the patient
      and their custodians, the patients are randomly allocated to one of the three retention
      groups as follow: A) bonded retainer 13-23, B) bonded retainer 12-22 and C) removable
      vacuum-formed retainer (VFR) covering the maxillary teeth including the second molars. The
      randomization process is prepared by an independent person and carried out by three staff
      members not involved in the trial. The randomization uses blocks of 30. The randomization
      notes is delivered in a sealed opaque envelope each. Every new participant picked an envelope
      and reveal the group assignment by opening the envelope. Recruitment is ongoing until the
      total number of participants meet the estimated sample size.
    

Intervention name(s): Measuring changes of Little´s irregularity index ( sum of 5 contact point discrepancies together) measured in mm 2 years after retention have been I place.
Intervention type(s): Other
Intervention description(s): Measuring changes occurred under 2 years which the retention devices have been in place between the groups
Other intervention name(s): Measuring changes of 5 single Contact point displacements in mm 2 years after retention have been I place.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Three groups with different retention devices
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Retention devices; Relapse; Maxillary incisors; Irregularity