An interventional study of myobrace appliance and Twin block in Class II Division 1 Adolescent Patients, sponsored by University of Baghdad. Enrolling by invitation at 1 site in Iraq. Open to participants aged 10 Years to 14 Years. Per ClinicalTrials.gov, last updated 2025-05-16.
Sponsored by University of Baghdad · Not applicable, Interventional, and Treatment
This study is intended primarily to compare the effects of two Class II correction appliances, namely Twin block and Myobrace appliances, on pharyngeal airway dimensions during the treatment of class II division 1 adolescent patients, also evaluates three dimensional (3D) changes of pharyngeal airway including: minimum cross-sectional area and volume using Cone Beam Computed Tomography (CBCT), skeletal, dentoalveolar, and soft tissue changes using cephalometric analysis, and three dimensional (3D) soft tissue changes using facial scans. The hypothesis being a consideration of no significant difference in the changes of pharyngeal airway and facial dimensions in skeletal class II patients before and after treatment with Twin block and Myobrace.
This study is a multicenter randomized comparative clinical trial, employing non-stratified randomization in two-parallel arms with equal allocation ratio of 1:1. Patients will be recruited from Orthodontic Clinic at the College of Dentistry, University of Kufa, and from specialized dental centers affiliated to the Iraqi Ministry of Health, in addition to some private clinics. Initially, the patients will be assessed for eligibility to participate in the study according to the inclusion criteria. Then, the parents will be informed verbally about the purpose of the study and will be provided with the informed consent form to be signed. Patients will be treated using two types of functional appliances ( Twin Block and Myobrace) for six months. Regular follow-ups will be conducted during the course of the treatment and progress will be charted out at 4-weeks intervals.
Participants will be randomly assigned to one of two groups, each receiving one of the specified treatments over a six-month period.
Group I: Twin Block Appliance
Group II: Myobrace Appliance
Imaging Protocols:
three dimensional (3D) Facial Scanning:
Data Analysis:
Measurements:
University of Baghdad is the lead sponsor of 164 studies on the registry; 66 are open to participants now.
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Exclusion Criteria:
It consists of maxillary and mandibular appliances that fit tightly against the teeth, alveolus, and adjacent supporting structures. Adams' clasps will be used bilaterally to anchor them to the first permanent molars and lower first premolars. A short passive labial bow will be added to the upper arch and ball end clasps to the interproximal areas of the lower arch for retention. The appliance will be fabricated after a symmetric protrusive bite registration using pink modeling wax sheets, in which the patients will rehearse many times before registration. The inclined bite blocks (ramps) will be at 70 which acts as a guiding mechanism for forward displacement of the mandible. The working bite will be taken with the incisors in an edge-to-edge relationship if possible and 2 to 3 mm bite opening between the central incisors. All the subjects will be instructed to wear the appliance 24 hours/day except for brushing. If further advancement
Device: Twin block
The appropriate size of Myobrace is chosen by using a special ruler to measure the distance between the distal portion of the lateral upper right incisor and the left, regardless of any crowding or diastema. The measure is based on the mesial-distal dimensions of the upper incisors, and not on their position. This distance is used to determine the correct size using a special table. Once chosen and inserted in patient's mouth, upper canines, even if not yet erupted, must be in their slots, so that the dental mildines coincided with the appliance's midline. In the first week, the patients will be instructed to gradually increase the wearing time of the appliance during the daytime. By the start of the second week, the patients will be instructed to wear the appliance achieving at least 8 hours during sleeping. By the end of the first 4 weeks, the patients will wear the appliances minimum of 1- 2 hours during the day plus the overnig
Device: myobrace appliance
functional appliance
functional appliance
minimum cross-sectional area of the pharyngeal airway in (mm^2) using Cone Beam Computed Tomography (CBCT)
3D measurements of pharyngeal airway minimum cross-sectional (mm\^2) will be performed for all participants of both groups at two stages before treatment and at the end of the study using CBCT
Time frame: From enrollment to the end of treatment at 6 months
three dimensional changes in the volume of the pharyngeal airway using CBCT
1. pharyngeal airway volume in (mm\^3) using CBCT.
Time frame: From enrollment to the end of treatment at 6 months
Skeletal changes using cephalometric analysis
* SNA angle (relative anteroposterior position of maxilla to anterior cranial base). * SNB angle (relative anteroposterior position of mandible to anterior cranial base). * ANB angle (relative anteroposterior position of maxilla to mandible). * SN-Pog angle (relative anteroposterior position of chin to anterior cranial base). * PP-MP (Angle between palatal and mandibular plane). * SN-MP (Angle between SN and mandibular plane). * Ar-Go-Me ((Gonial Angle, it refers to the relation between the body of the mandible and the ramus).
Time frame: From enrollment to the end of treatment at 6 months
Soft tissue changes using cephalometric analysis
* NL angle (nasolabial angle). * U Lip-E line (upper lip to Rickett's Esthetic line). * L Lip-E Line (lower lip to Rickett's Esthetic line).
Time frame: From enrollment to the end of treatment at 6 months
Dentoalveolar changes using cephalometric analysis
* U1-PP (upper incisor inclination to the palatal plane). * L1-MP (lower incisor inclination to the mandibular plane).
Time frame: From enrollment to the end of treatment at 6 months
Dental changes using study models
overjet, overbite, inter canine, inter premolar, and inter molar widths in (mm)
Time frame: From enrollment to the end of treatment at 6 months
three dimentional soft tissue changes using facial scans
Total face height (mm) Upper anterior face height (mm) Lower anterior face height (mm) Bigonial width (mm) Mandibular length (mm) Soft tissue convexity angle Total face convexity angle Gonial angle Alar base width (mm) Lip width (mm) Nasolabial angle Labiomental angle
Time frame: From enrollment to the end of treatment at 6 months
Plan to share: Yes — De-identified individual participant data (IPD) will be shared, including 3D facial scans, CBCT airway volume measurements, and linear and angular facial measurements. The shared data will not contain any personally identifiable information. Data will be made available upon reasonable request for research purposes related to orthodontic treatment, airway evaluation, and facial growth analysis. Access will be granted to qualified researchers through a data-sharing agreement, ensuring compliance with ethical guidelines and patient privacy regulations.
Supporting information: Study protocol, Sap, Icf
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University of Baghdad