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

March 2, 2026 updated by: Bezmialem Vakif University
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).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

34

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Fatih
      • Istanbul, Fatih, Turkey (Türkiye), 34093
        • Bezmialem Vakif University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Clear Aligner Group
Mandibular advancement with clear aligners
Device: Invisalign Clear Aligners
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.
Experimental: Twinblock Group
Mandibular Advancement with Twinblock Functional Appliance
Device: Twinblock Functional Appliance
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Baseline and after completion of functional appliance therapy (approximately 7-13 months)
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.
Baseline and after completion of functional appliance therapy (approximately 7-13 months)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bezmialem Vakif University

Investigators

  • Study Chair: Ezgi Sunal Akturk, Assistant Professor, Saglik Bilimleri Universitesi
  • Study Chair: Gokmen Kurt, Professor, Bezmialem Vakif University
  • Principal Investigator: Ahsen Irem Toktas, Research Assistant, Bezmialem Vakif University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 1, 2023

Primary Completion (Actual)

July 22, 2025

Study Completion (Actual)

August 1, 2025

Study Registration Dates

First Submitted

August 25, 2025

First Submitted That Met QC Criteria

March 2, 2026

First Posted (Actual)

March 6, 2026

Study Record Updates

Last Update Posted (Actual)

March 6, 2026

Last Update Submitted That Met QC Criteria

March 2, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 118118

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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