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Completed

NCT Number: NCT07454694

Comparison Of The Effects Of Clear Aligners And Twinblock Appliances In Functional Treatment Of Class II Malocclusion

This prospective clinical study aimed to compare the skeletal and dentofacial effects of Twin Block (TWB) and clear aligners with mandibular advancement, and to evaluate mandibular trabecular bone changes through fractal analysis (FA).

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Key information

Conditions

Class II Malocclusion Malocclusion Malocclusion, Angle Class II Mandibular Retrognathism Overbite Stomatognathic Diseases Tooth Diseases

Age range

10 year–14 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Bezmialem Vakif University

Istanbul, Fatih, 34093, Turkey (Türkiye)

About this study

A total of 34 patients with dentoskeletal Class II malocclusion were included in the study: 16 patients in the Invisalign® Mandibular Advancement (MA) group and 18 patients in the TWB group .Panoramic and lateral cephalometric radiographs were obtained at baseline(T0) and after functional treatment(T1). Skeletal, dental, and soft tissue structures were evaluated on the pretreatment and posttreatment radiographs using cephalometric analysis, while trabecular bone architecture was assessed by fractal analysis.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients with Angle Class II molar and canine relationship
  • Overjet greater than 6 mm
  • Patients in the growth spurt period

Exclusion criteria

  • History of orthodontic treatment
  • Missing teeth
  • Patients in mixed dentition period
  • Systemic diseases affecting growth or bone metabolism

Treatment and study plan

Invisalign Clear Aligners

Device

Functional appliances are used for mandibular advancement in the treatment of mandibular retrognathia in orthodontics. The Twinblock is a conventional functional appliance, and nowadays mandibular advancement can also be achieved with clear aligners. In this study, these two appliances were used.

Twinblock Functional Appliance

Device

Functional appliances are used for mandibular advancement in the treatment of mandibular retrognathia in orthodontics. The Twinblock is a conventional functional appliance, and nowadays mandibular advancement can also be achieved with clear aligners. In this study, these two appliances were used.

Primary outcomes

  1. Change from Baseline in Cephalometric Measurements (mm and degrees) After Functional Appliance Therapy

    Time frame: Baseline and after completion of functional appliance therapy (approximately 7-13 months)

    Cephalometric measurements will be evaluated on lateral cephalometric radiographs using a customized analysis derived from Steiner, McNamara, Tweed, Ricketts, and Arnett analyses.

    A total of 47 skeletal, dental, airway, hyoid, and soft tissue parameters will be assessed. Linear measurements will be recorded in millimeters (mm) and angular measurements in degrees. Landmarks will be manually identified on digital lateral cephalometric radiographs.

  2. Change from Baseline in Mandibular Bone Fractal Dimension Values After Functional Appliance Therapy

    Time frame: Baseline and after completion of functional appliance therapy (approximately 7-13 months)

    Fractal dimension values will be calculated using the box-counting method on panoramic radiographs (mandibular condyle, angulus, and corpus) and lateral cephalometric radiographs (symphysis).

    Fractal dimension is a unitless numerical value used to evaluate trabecular bone complexity. Higher values indicate greater trabecular complexity, whereas lower values indicate reduced trabecular structure.

Sponsors and collaborators

Lead sponsor

Bezmialem Vakif University

Other

Registry information

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Mar 6, 2026
Registry last updated
Mar 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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