Effectiveness of Modified Functional Appliance With Expander

Study Overview
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Brief Summary
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This clinical trial compares the effectiveness of a myofunctional appliance that uses a clear and modified twin block appliance with an expander made from 2mm biocompatible polyethylene terephthalate modified with Glycol thermoplastic material with a conventional twin block appliance with an expander. The trial will be conducted on adolescent patients with class II division 1.

Detailed Description
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In a multicenter single-blinded randomized clinical trial study with two-arm parallel groups, a computer random generator will develop a simple randomization with an equal allocation ratio (1:1) and without stratification. The investigator will initially assess the patients for eligibility to be included in the study. Those who will meet the inclusion criteria, the parents will be informed about the nature of the study verbally to get the initial approval for participation. Then they will be provided with the patient information sheet and consent form. According to the sample size calculation, 48 patients will be recruited (24 for each group), and impressions and lateral cephalometric radiography will be taken before treatment and bite registration then the appliance inserted, and the patient will be checked every two weeks for expansion and every four weeks for overjet recording. The treatment will be continuing for 6 months to take final records. The collected data will include cephalometric evaluation, clinical evaluation, scanned upper model evaluation, and finally patient satisfaction from the appliance. Data will be analyzed using Statistical Package for Social Sciences for Windows, version 26.0 including descriptive statistic (number, mean, and standard deviation), Reliability statistic (interclass correlation coefficient), and Inferential statistics (independent samples t-test).

Official Title
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A Modified Removable Orthodontic Appliance for Maxillary Expansion and Treatment of Class II Malocclusion: A Randomized Clinical Trial

Conditions
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Class II Malocclusion

Intervention / Treatment
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* Device: Modified twin block appliance with expander
* Device: Conventional twin block appliance with expander


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients' age at the start of treatment: at growth spurt [in stage 2 (Acceleration) - 3 (Transition) of cervical vertebral maturation]. Skeletal and dental relationships: skeletal class II with normal maxilla and retrognathic mandible. Moderate to severe dental class II division 1 malocclusion with overjet ≥ 8 mm. Horizontal/normal growth pattern. Convex profile with decreased or normal lower facial height (clinically and radiographically). Well-aligned/mild crowding of maxillary and mandibular dental arches. Good oral health free from caries and periodontal problems at the start of treatment. Exclusion Criteria: Patients with vertical growth pattern or backward mandibular rotation tendency. Patients with open bite Patients with obvious facial asymmetry. Patients with orofacial clefting. Patients with bad oral habits. Active periodontal disease.

Ages Eligible for Study
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Minimum Age: 10 Years
Maximum Age: 13 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The patients will be treated with twin block appliance
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Modified twin block appliance with expander group<br>For 24 patients with class II division malocclusion in their growing stages, using a 2 mm biocompatible and rigid PET-G thermoforming material to create two clear appliances for each patient. The material will be adapted separately on maxillary and mandibular casts using a pressure molding vacuum machine. Then, the appliances will be trimmed and finished and transferred to the articulator with the aid of a pre-existing working wax bite. The ramps will be made of cold cure acrylic on the thermoplastic sheets. Next, the expansion screw will be placed in the midline of the maxillary cast, and the maxillary appliance will be split midpalatally to fit the patient's individual needs. | Device: Modified twin block appliance with expander<br>* These appliances are myofunctional appliance used for treating class II division growing adolescents.<br>Device: Conventional twin block appliance with expander<br>* These appliances are myofunctional appliances used for treating class II division growing adolescents.<br>|
| Experimental: Conventional twin block appliance with expander group<br>For 24 patients in a growing stage with class II division 1 malocclusion, these appliances will consist of removable maxillary and mandibular appliances. These will have a labial bow, Adam's clasps on the first molars, ball end clasps with incisal capping and expansion screw. The inclined bite blocks (ramps) will act as a guide to move the mandible forward. | Device: Modified twin block appliance with expander<br>* These appliances are myofunctional appliance used for treating class II division growing adolescents.<br>Device: Conventional twin block appliance with expander<br>* These appliances are myofunctional appliances used for treating class II division growing adolescents.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anteroposterior skeletal changes | Skeletal changes using cephalometric radiographs including different angular measurements to estimate the changes between dental bases before and after treatment. | T0 (before treatment), T1 (at end of the study) around 6-9 months | 
| Vertical skeletal changes | Skeletal changes using cephalometric radiographs including different linear measurements to estimate the changes between dental bases before and after treatment. | T0 (before treatment), T1 (at end of the study) around 6-9 months. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Soft tissue change | Measurements using cephalometric radiographs including different angular measurements to estimate the soft tissue changes before and after treatment. | T0 (before treatment), T1 (at end of the study) around 6-9 months | 
| Dentoalveolar changes | Measurements using cephalometric radiographs include different angular measurements to estimate the changes between teeth before and after treatment. | T0 (before treatment), T1 (at end of the study) around 6-9 months | 
| Study model evaluation | The scanned upper study model will be used to calculate the amount of expansion before and at the end of the study. | T0 (before treatment), T1 (at end of the study) around 6-9 months. | 
| Patient satisfaction from the appliance | Patient satisfaction with both appliances will be estimated using a questionnaire at the middle of treatment. | around 4 months. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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twin block, thermoplastic material, clear expander,, adolescent, clinical trial