Skeletal Class II MalocclusionNCT07687927
Fixed Versus Conventional Twin Block Appliances for Skeletal Class II Malocclusion
A study testing Conventional Twin Block Appliance in people with Skeletal Class II Malocclusion and Mandibular Retrognathia, run by Al-Azhar University at 1 site in Egypt.
Trial summary
This study compares two types of dental appliances a fixed Twin Block appliance and a conventional (removable) Twin Block appliance used to treat a bite problem called skeletal Class II malocclusion in growing children and teenagers. In this condition, the lower jaw is positioned further back than the upper jaw. Read more about this study
- Who is it for?
- Ages 11 to 15 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Skeletal Class II Malocclusion, Mandibular Retrognathia
- What is being tested?
- Conventional Twin Block Appliance
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteEgypt
- Study dates
- 8 Nov 2023to 24 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 11 to 15 years
- Men only
- Healthy volunteers accepted
- Child
Who may be able to join
- Growing male patients (as judged from clinical examination and confirmed later by (CVM)
- Skeletal class II with retrognathic mandible.
- Healthy compliant and motivated patient.
- No Previous orthodontic treatment.
- No Severe facial asymmetry determined by clinical or radiographic examination.
- No Systemic diseases that may affect the treatment results.
- No tmj disorders.
Who cannot join
- Previous orthodontic treatment.
- Poor oral hygiene.
- Severe facial asymmetry determined by clinical or radiographic examination.
- Systemic disease that may affect the treatment results. 5. TMJ disorders.
Trial locations and contacts
1 site in 1 country.
Egypt1 site
Faculty of Dental Medicine, Al-Azhar University
Cairo, Cairo Governorate, 11765
About this study
Official title: Dentoskeletal and Condylar Evaluation of Skeletal Class II Malocclusion by Fixed Twinblock Appliance Versus Conventional Twin Block Appliance Cone Beam Computed Tomography Study
This study compares two types of dental appliances a fixed Twin Block appliance and a conventional (removable) Twin Block appliance used to treat a bite problem called skeletal Class II malocclusion in growing children and teenagers. In this condition, the lower jaw is positioned further back than the upper jaw. Both appliance types work by guiding the lower jaw forward during growth. The study uses 3D imaging (cone beam computed tomography, or CBCT) before and after treatment to measure how each appliance affects the bones of the jaw, the teeth, the soft tissue profile of the face, and the jaw joint (temporomandibular joint). The goal is to determine whether the fixed or the conventional version of the appliance produces better treatment outcomes.
Read the detailed description
This comparative clinical study evaluates the skeletal, dentoalveolar, soft-tissue, and condylar/temporomandibular joint (TMJ) effects of fixed versus conventional Twin Block appliances in growing patients diagnosed with skeletal Class II malocclusion due to mandibular retrognathia. Participants were allocated to receive treatment with either a fixed or a conventional (removable) Twin Block appliance. Pre-treatment and post-treatment cone beam computed tomography (CBCT) scans were obtained to assess sagittal jaw relationships, mandibular advancement, dentoalveolar changes (including overjet and overbite correction), soft-tissue profile changes, and condylar position/remodeling within the glenoid fossa, including TMJ disc space measurements. Outcomes between the two appliance groups were compared to evaluate differences in skeletal and dental effects, as well as any differences in condylar/TMJ adaptation associated with each appliance design.
- Being tested
- Conventional Twin Block Appliance
- Keywords
- Twin Block Appliance, Mandibular Advancement, Functional Appliance, Cone Beam Computed Tomography, Temporomandibular Joint, Growing Patients, Class II Malocclusion
- Medical subject headings
- Micrognathism, Overbite
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Conventional Twin Block ApplianceDevice
A removable functional appliance consisting of upper and lower acrylic occlusal bite blocks used to advance the mandible and correct skeletal class II malocclusion in growing patients
| Study group | Role | What they receive |
|---|---|---|
| Fixed twin block group | Experimental | Patients treated with a fixed (bonded) Twin Block appliance for correction of skeletal Class II malocclusion due to mandibular retrognathia. Receives: Device: Conventional Twin Block Appliance |
| Conventional Twin Block Group | Active comparator | Patients treated with a conventional (removable) twin block appliance for correction of skeletal class II malocclusion due to mandibular retrognathia Receives: Device: Conventional Twin Block Appliance |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Sagittal Skeletal Relationship (ANB Angle)
Measured using cone beam computed tomography (CBCT), the ANB angle reflects the anteroposterior relationship between the maxilla and mandible. Pre-treatment and post-treatment values will be compared between the fixed and conventional Twin Block appliance groups to assess skeletal correction of Class II malocclusion.
Measured: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)
Secondary outcomes (2)
Change in Sagittal Skeletal Relationship (ANB Angle)
Measured using cone beam computed tomography (CBCT), the ANB angle reflects the anteroposterior relationship between the maxilla and mandible. Pre-treatment and post-treatment values will be compared between the fixed and conventional Twin Block appliance groups to assess skeletal correction of Class II malocclusion.
Measured: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)
Change in Condylar Position and TMJ Disc Space
Measured using cone beam computed tomography (CBCT), condylar position within the glenoid fossa will be assessed by evaluating anterior, superior, and posterior joint spaces. TMJ disc space measurements will also be recorded to evaluate condylar remodeling and adaptation. Pre-treatment and post-treatment values will be compared between the fixed and conventional Twin Block appliance groups.
Measured: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Jul 2026
- Study start8 Nov 2023
- Primary completion23 Dec 2025
- Study completion24 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Skeletal Class II MalocclusionStudies of the same condition, open and under way.
- More trials run by Al-Azhar UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- Two parallel groups: fixed Twin Block appliance versus conventional Twin Block appliance.
- Masking
- None (open label)
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Al-Azhar University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Omneya mohamed abo el yazeed, Al-Azhar University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07687927
- Sponsor's protocol ID
- AzharOrtho-TwinBlock-25
- Status last verified
- Jun 2026
- First submitted
- 30 Jun 2026
- Last updated
- 7 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dentoskeletal and Condylar Evaluation of Skeletal Class II Malocclusion by Fixed Twinblock Appliance Versus Conventional Twin Block Appliance Cone Beam Computed Tomography Study
- ClinicalTrials.gov ID
- NCT07687927
- Acronym / sponsor ID
- AzharOrtho-TwinBlock-25
- Keywords
- Twin Block Appliance, Mandibular Advancement, Functional Appliance, Cone Beam Computed Tomography, Temporomandibular Joint, Growing Patients, Class II Malocclusion
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Al-Azhar UniversityUniversity, hospital or other
- Study start
- 8 Nov 2023 (actual)
- Primary completion
- 23 Dec 2025 (actual)
- Study completion
- 24 Dec 2025 (actual)
- First posted
- 7 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study compares two types of dental appliances a fixed Twin Block appliance and a conventional (removable) Twin Block appliance used to treat a bite problem called skeletal Class II malocclusion in growing children and teenagers. In this condition, the lower jaw is positioned further back than the upper jaw. Both appliance types work by guiding the lower jaw forward during growth. The study uses 3D imaging (cone beam computed tomography, or CBCT) before and after treatment to measure how each appliance affects the bones of the jaw, the teeth, the soft tissue profile of the face, and the jaw joint (temporomandibular joint). The goal is to determine whether the fixed or the conventional version of the appliance produces better treatment outcomes.
Detailed description
This comparative clinical study evaluates the skeletal, dentoalveolar, soft-tissue, and condylar/temporomandibular joint (TMJ) effects of fixed versus conventional Twin Block appliances in growing patients diagnosed with skeletal Class II malocclusion due to mandibular retrognathia. Participants were allocated to receive treatment with either a fixed or a conventional (removable) Twin Block appliance. Pre-treatment and post-treatment cone beam computed tomography (CBCT) scans were obtained to assess sagittal jaw relationships, mandibular advancement, dentoalveolar changes (including overjet and overbite correction), soft-tissue profile changes, and condylar position/remodeling within the glenoid fossa, including TMJ disc space measurements. Outcomes between the two appliance groups were compared to evaluate differences in skeletal and dental effects, as well as any differences in condylar/TMJ adaptation associated with each appliance design.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Two parallel groups: fixed Twin Block appliance versus conventional Twin Block appliance.
| Arm | Type | Receives |
|---|---|---|
| Fixed twin block group | Experimental | Device: Conventional Twin Block AppliancePatients treated with a fixed (bonded) Twin Block appliance for correction of skeletal Class II malocclusion due to mandibular retrognathia. |
| Conventional Twin Block Group | Active comparator | Device: Conventional Twin Block AppliancePatients treated with a conventional (removable) twin block appliance for correction of skeletal class II malocclusion due to mandibular retrognathia |
Who may qualify
- Ages
- 11 to 15 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (7 listed)
- Growing male patients (as judged from clinical examination and confirmed later by (CVM)
- Skeletal class II with retrognathic mandible.
- Healthy compliant and motivated patient.
- No Previous orthodontic treatment.
- No Severe facial asymmetry determined by clinical or radiographic examination.
Key exclusion criteria (4 listed)
- Previous orthodontic treatment.
- Poor oral hygiene.
- Severe facial asymmetry determined by clinical or radiographic examination.
- Systemic disease that may affect the treatment results. 5. TMJ disorders.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Conventional Twin Block ApplianceA removable functional appliance consisting of upper and lower acrylic occlusal bite blocks used to advance the mandible and correct skeletal class II malocclusion in growing patients | Device | Conventional Twin Block Group, Fixed twin block group |
Primary outcome
Change in Sagittal Skeletal Relationship (ANB Angle)
Time frame: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)
Measured using cone beam computed tomography (CBCT), the ANB angle reflects the anteroposterior relationship between the maxilla and mandible. Pre-treatment and post-treatment values will be compared between the fixed and conventional Twin Block appliance groups to assess skeletal correction of Class II malocclusion.
2 secondary outcomes
Change in Sagittal Skeletal Relationship (ANB Angle)
Time frame: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)
Change in Condylar Position and TMJ Disc Space
Time frame: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Jul 2026.
- Individual participant dataSharing planned: No
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Modified Versus Clear Twin Block for Skeletal Class II Malocclusion
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"Sliding Jigs vs Retraction Hooks for Maxillary Dentition Distalization Using IZC Miniscrews"
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Conventional Twin Block Appliance in people with Skeletal Class II Malocclusion and Mandibular Retrognathia, run by Al-Azhar University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Sagittal Skeletal Relationship (ANB Angle) (time frame: Measured at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jul 2026; AzTrials last refreshed its copy on 1 Nov 2026.