Efficacy and Cost-effectiveness of Orthodontic Retention Protocols (orthoretenti)

University of Zagreb School of Dental Medicine, Zagreb, Croatia, University of Rijeka Faculty of Dental Medicine, Rijeka, Croatia

Objective is to assess changes of dentition and periodontium, and hygiene in retention after the end of the active phase of orthodontic treatment, and relationship with gender, type of retention appliance, pre-therapeutic condition of dentition and duration of active phase of treatment.

A total of 152 subjects will be recruited and randomly assigned into three groups. First group will have a square 8-stranded 0.673x0.268 mm retainer wire bonded in mandibular teeth after completing the active phase of comprehensive orthodontic treatment with fixed appliances. Retainer will be bonded on lingual site canine to canine on each tooth. Second group will have a round 6-stranded 0.40 mm retainer in mandible. Third group will be without fixed retainer, only with thermoplastic vacuum-formed removable Essix retainer in mandible. Subjects will be examined before orthodontic treatment (T0), upon completion of treatment (T1), six months in retention (T2), two years (T3) and three years in retention (T4). Changes in intercanine width, relapse (unexpected tooth movements), retainer failure, accumulation of biofilm, calculus and gingivitis will be assessed.

0.673 x 0.268 mm 8-stranded wire Bond A Braid (Reliance Orthodontic Products, USA) will be bonded in mandible canine to canine on each tooth using Filtek flowable composite (Ivoclar Vivadent, Lichtenstein) and Multilink adhesive (3M, USA).

0.40 mm round 6-stranded wire (Forestadent, Germany) will be bonded on 6 mandibular frontal teeth, canine to canine on each tooth using Filtek flowable composite (Ivoclar Vivadent, Lichtenstein) and Multilink adhesive (3M, USA).

the unabbreviated scale title: Little Irregularity Index (used to measure the crowding)- numerical rating scale in millimeters the minimum and maximum values: 0,10 higher scores mean a worse outcome lower scores mean a better outcome

the unabbreviated scale title: Little Irregularity Index (used to measure the crowding)- numerical rating scale in millimeters the minimum and maximum values: 0,10 higher scores mean a worse outcome lower scores mean a better outcome

the unabbreviated scale title: Little Irregularity Index (used to measure the crowding)- numerical rating scale in millimeters the minimum and maximum values: 0,10 higher scores mean a worse outcome lower scores mean a better outcome

percentage of cases with at least one fixed retainer failure, the minimum and maximum values 0%,100% higher scores mean a worse outcome, lower scores mean a better result

percentage of cases with at least one fixed retainer failure, the minimum and maximum values 0%,100% higher scores mean a worse outcome, lower scores mean a better result

the unabbreviated scale title: Silness and Loe Plaque Index-ratio of measuring sites in mandibular central sextant; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better result

the unabbreviated scale title: Silness and Loe Plaque Index-ratio of measuring sites in mandibular central sextant; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better result

percentage of cases with intercanine width change, the minimum and maximum values 0%,100% higher scores mean a worse outcome, lower scores mean a better result

the unabbreviated scale title: intercanine width change in millimeters, the minimum and maximum values 0,5, higher scores mean a worse outcome, lower result mean a better outcome

the unabbreviated scale title: Calculus Surface Index (CSI)-ratio of measuring sites in mandibular central sextant; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better outcome

the unabbreviated scale title: Calculus Surface Index (CSI)-ratio of measuring sites in mandibular central sextant; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better outcome

the unabbreviated scale title: percentage of relapsed cases; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better outcome

the unabbreviated scale title: percentage of relapsed cases; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better outcome

the unabbreviated scale title: Bleeding on probing (BOP)-ratio of measuring sites in mandibular central sextant; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better result

the unabbreviated scale title: Bleeding on probing (BOP)-ratio of measuring sites in mandibular central sextant; the minimum and maximum values 0%,100%, higher scores mean a worse outcome, lower scores mean a better result

Participant's satisfaction with stability of results as assessed using a 5-point Likert scale. Scores range from "very unsatisfied" (1) to "very satisfied" (5). Higher scores mean a better outcome, lower scores mean a worse outcome

the unabbreviated scale title: number of check-ups in retention period; the minimum and maximum values 0,10; higher scores mean a worse outcome, lower scores mean a better result the minimum and maximum values: 0,30

Inclusion Criteria: finished orthodontic treatment, participants must have all permanent teeth Exclusion Criteria: hypodontia, missing teeth