Fixed Versus Conventional Twin Block Appliances for Skeletal Class II Malocclusion

NCT07687927 | Completed

• 1 other identifier: AzharOrtho-TwinBlock-25
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Skeletal Class II Malocclusion; Mandibular Retrognathia

Keywords

Twin Block Appliance; Mandibular Advancement; Functional Appliance; Cone Beam Computed Tomography; Temporomandibular Joint; Growing Patients; Class II Malocclusion

Outcome Measures

Primary Outcomes (1)

• 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 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 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 at baseline (pre-treatment) and at the end of active treatment (approximately 12-18 months, based on actual treatment duration)

Study Arms (2)

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.

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

Device: Conventional Twin Block Appliance

Interventions

Conventional Twin Block Appliance DEVICE

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

Conventional Twin Block Group; Fixed twin block group

Eligibility Criteria

• Age: 11 Years - 15 Years
• Gender Eligibility Details: Male patients
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Al-Azhar University: lead

Study Sites (1)

Faculty of Dental Medicine, Al-Azhar University

Cairo, Cairo Governorate, 11765, Egypt

Location

MeSH Terms

Conditions

Micrognathism; Overbite

Condition Hierarchy (Ancestors)

Jaw Abnormalities; Jaw Diseases; Musculoskeletal Diseases; Maxillofacial Abnormalities; Craniofacial Abnormalities; Musculoskeletal Abnormalities; Stomatognathic Diseases; Stomatognathic System Abnormalities; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Malocclusion, Angle Class II; Malocclusion; Tooth Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: M.Sc. Candidate, Department of Orthodontics, Faculty of Dental Medicine, Al-Azhar University

Model Details: Two parallel groups: fixed Twin Block appliance versus conventional Twin Block appliance.

Study Record Dates

• First Submitted: June 30, 2026
• First Posted: July 7, 2026
• Study Start: November 8, 2023
• Primary Completion: December 23, 2025
• Study Completion: December 24, 2025
• Last Updated: July 7, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

EG (1)