Modified Versus Clear Twin Block for Skeletal Class II Malocclusion (NCT07608406) | Clinical Trial Compass
Active — Not RecruitingNot Applicable
Modified Versus Clear Twin Block for Skeletal Class II Malocclusion
Syria40 participantsStarted 2026-05-17
Plain-language summary
This study aims to evaluate the effectiveness of a modified Twin Block appliance compared to a conventional clear Twin Block appliance in the treatment of skeletal Class II malocclusion caused by mandibular retrusion in growing patients.
This is a two-arm randomized controlled clinical trial including patients aged 10-13 years diagnosed with skeletal Class II malocclusion. Participants will be randomly allocated into two equal groups.
Skeletal, dental, and soft tissue changes will be assessed using lateral cephalometric analysis and cone-beam computed tomography (CBCT). Additionally, temporomandibular joint (TMJ) health, pain perception, and functional tolerance will be evaluated using standardized clinical indices and patient-reported outcome measures.
The study aims to compare the modified appliance with the conventional design in terms of skeletal improvement, TMJ safety, and patient acceptance.
Who can participate
Age range
10 Years – 13 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Systemically healthy patients.
* Patients willing to accept removable functional appliance therapy.
* Skeletal Class II malocclusion (Angle Class II Division 1).
* Skeletal Class II due to mandibular retrusion (ANB \> 5°, Wits appraisal \> 5 mm, SNB \< 78°, NSAr ≥ 125°, with normal maxillary position).
* Normal or horizontal growth pattern (MM angle \< 30° or Björk angle \< 40°).
* Growth stage corresponding to MP3 stage or pre-pubertal peak according to hand-wrist radiograph (Björk and Helm, 1967).
* No severe dental crowding in the dental arches and no significant maxillary dental protrusion.
* Absence of congenital anomalies, trauma, burns, or surgical scars affecting the temporomandibular joint or craniofacial structures.
* Absence of systemic or rheumatologic diseases affecting the temporomandibular joint.
Exclusion Criteria:
* Presence of clinical signs or symptoms of temporomandibular joint disorders.
* Functional mandibular deviation.
* Presence of unilateral or bilateral posterior crossbite.
* Previous orthodontic treatment.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in mandibular skeletal position measured by SNB angle on lateral cephalometric radiographs
Timeframe: Baseline (T0) and after 7 months of treatment (T1)
2
Change in effective mandibular length measured by Co-Gn distance on lateral cephalometric radiographs
Timeframe: Baseline (T0) and after 7 months of treatment (T1)
3
Change in condylar dimensions assessed using cone-beam computed tomography (CBCT)
Timeframe: Baseline (T0) and after 7 months of treatment (T1)
4
Change in temporomandibular joint spaces assessed using CBCT
Timeframe: Baseline (T0) and after 7 months of treatment (T1)