Effects of Class III Elastics on Stability of Orthopaedic Class III Correction

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the effects of adding elastics to orthodontic retainers on the stability of class III correction and whether it reduces the need for jaw surgery.

Detailed Description
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Over the years many types of appliances have been recommended for retaining Class III correction in growing children such as intermaxillary splints, class III activator, Frankel 3, Class III twin block, continued use of face-mask and chin-cup. However, currently none of these are in routine use and there is no evidence on the long term effectiveness of any retention protocol for class III correction. One of the most commonly used retainers following orthodontic treatment is clear plastic retainers. There are no studies that investigated whether using class III elastics in combination with clear plastic retainers improves the stability of class III correction and reduces the need for later jaw surgery.

Official Title
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Effects of Class III Elastics on Stability of Orthopaedic Class III Correction

Conditions
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Underbite, Class III Malocclusion

Intervention / Treatment
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* Other: Upper-lower clear plastic retainers + Class III elastics
* Other: Upper-lower clear plastic retainers


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients that completed their orthodontic treatment for the management of their skeletal class III with upper jaw retrusion that was treated with Class III orthopaedic appliances, followed by full fixed appliances. No congenital anomalies or craniofacial syndromes No other orthodontic treatment No medical history that effects growth Exclusion Criteria: Congenital anomalies or craniofacial syndromes Other orthodontic treatment Medical history that effects growth

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 16 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: Upper-lower clear plastic retainers + Class III elastics<br>Upper-lower clear plastic retainers + Class III elastics | Other: Upper-lower clear plastic retainers + Class III elastics<br>* Addition of Class III elastics to clear plastic retainers<br>|
| Active Comparator: Upper-lower clear plastic retainers<br>Upper-lower clear plastic retainers | Other: Upper-lower clear plastic retainers<br>* Upper-lower clear plastic retainers<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in overjet of participants in the 2 study arms | Measurement of overjet | 5 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Need for jaw surgery | Need for surgery assessed by a panel of orthodontists | 5 years | 
| Difference in upper jaw position | The difference in SNA angle measured on cephalometric radiographs between groups | 5 years | 
| Difference in lower jaw position | The difference in SNB angle measured on cephalometric radiographs between groups | 5 years | 
| Difference in upper-lower jaw relationship | The difference in ANB angle measured on cephalometric radiographs between groups | 5 years | 
| Difference in upper incisor angulation | The difference in upper incisor angle measured on cephalometric radiographs between groups | 5 years | 
| Difference in lower incisor angulation | The difference in lower incisor angle measured on cephalometric radiographs between groups | 5 years | 
| Compliance and ease of use of both retention regimens | Questionnaire on the frequency and ease of use of both retainer regimens will be used | 5 years | 
| Effect of elastics on alignment retention | Little's irregularity index will be used to compare both groups | 5 years | 
| Periodontal health, including recession around the incisors | Presence of gingival recession and prominence of lower incisors will be evaluated for both groups | 5 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Class III Malocclusion, Orthodontic retention