Efficacy and Cost-effectiveness of Orthodontic Retention Protocols

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Efficacy and Cost-effectiveness of Orthodontic Retention Protocols

Conditions
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Orthodontic Relapse

Intervention / Treatment
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* Device: fixed retainer
* Device: removable retainer


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

Ages Eligible for Study
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Minimum Age: 11 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: fixed mandibular lingual rectangular retainer 0.673 x 0.268 mm<br>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). | Device: fixed retainer<br>* bonded lingual mandibular fixed retainer on frontal teeth 33-43<br>|
| Experimental: fixed mandibular lingual round retainer 0.40 mm<br>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). | Device: fixed retainer<br>* bonded lingual mandibular fixed retainer on frontal teeth 33-43<br>|
| Active Comparator: removable mandibular retainer<br>Group without fixed retainer will be wearing removable thermoplastic vacuum-formed Essix retainer | Device: removable retainer<br>* thermoplastic vacuum-formed removable mandibular retainer<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| severity of relapse (unexpected tooth movement in mandibular frontal area) at 1 year | 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 | 1 year | 
| severity of relapse (unexpected tooth movement in mandibular frontal area) at 2 years | 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 | 2 years | 
| severity of relapse (unexpected tooth movement in mandibular frontal area) at 3 years | 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 | 3 years | 
| incidence of retainer failure (debonding, breakage) at 2 years | 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 | 2 years | 
| incidence of retainer failure (debonding, breakage) at 3 years | 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 | 3 years | 
| extent of biofilm accumulation at 2 years | 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 | 2 years | 
| extent of biofilm accumulation at 3 years | 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 | 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| incidence of intercanine width change | 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 | 3 years | 
| changes of intercanine width | 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 | 2 years, 3 years | 
| extent of calculus accumulation at 2 years | 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 | 2 years | 
| extent of calculus accumulation at 3 years | 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 | 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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retention wire, fixed retainer, orthodontic therapy