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Completed

NCT Number: NCT07236775

Treatment Outcome of Clear Aligner and Traditional Fixed Appliances in Four Premolar Extraction Cases

Patients with severe crowding requiring the extraction of four premolars will be enrolled in this study. The degree of apical root resorption associated with using the clear aligner technique compared with vestibular fixed appliances in the treatment of severe crowding malocclusion cases requiring the extraction of first premolars will be evaluated using cone beam computed tomography (CBCT) volumes.

There are two groups:

First group (Experimental): the patients in this group will be treated using clear aligners.

Second group (Control): the patients in this group will be treated using fixed appliances.

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Key information

Conditions

Malocclusion, Class I/II Crowding, Tooth Malocclusion Stomatognathic Diseases Tooth Diseases

Age range

18 year–25 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Orthodontics, Faculty of Dentistry, University of Damascus

Damascus, Syria

About this study

With the increasing number of young adults requesting esthetic orthodontic treatment, clear aligners have continued to gain widespread use, driven by greater consideration of esthetic aspects and oral health-related quality of life compared to traditional fixed orthodontic appliances. Recently, clear aligners have been used in more complex malocclusion cases that require premolar extraction. Teeth root resorption occurs due to physiological or pathological causes that lead to loss of tooth structure. Apical root resorption (ARR) is a common side effect of orthodontic treatment that requires careful investigation of its location and frequency.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Adult patients aged 18-25 years.
  • Class I malocclusion with severe dental crowding.
  • Tooth size-arch discrepancy more than 6 mm.
  • No congenitally missing or extracted teeth (except for the wisdom teeth).
  • No history of previous trauma to the maxillofacial region or surgical interventions.

Exclusion criteria

  • Previous orthodontic treatment.
  • Presence of previously occurred ARR.
  • Patients with psychological abnormalities or systemic diseases.
  • Patients with known allergies to latex or plastic materials.

Treatment and study plan

Clear aligners

Device

In-house 3D-fabricated clear aligners will be used.

Traditional fixed appliances

Device

The ordinary metallic braces will be used in a conventional manner.

Primary outcomes

  1. Change in root length

    Time frame: First assessment: one day before the commencement of treatment (i.e., initiating orthodontic tooth movement). Second assessment: one day following the end of treatment (which is expected to occur within 12 to 18 months).

    The maximum linear lengths between the root apex and incisal edges (for the anterior teeth) or the cusp tips (for the posterior teeth) will be measured on the cone-beam computed tomography (CBCT) images.

    Differences between the measurements of each tooth before and after treatment provided the amount of apical root resorption in mm.

    The variable will be measured for each tooth (from the central incisors to the first molars) and on both jaws.

Sponsors and collaborators

Lead sponsor

Damascus University

Other

Registry information

Official study title

Evaluation of the Apical Root Resorption in Young Adults Caused by Orthodontic Treatment of Class I Severe Crowding Cases Using Clear Aligners Versus Traditional Fixed Appliances: A Randomized Controlled Clinical Trial

Important dates

Study start
2019
Primary completion
2021
Study completion
2022
First posted
Nov 19, 2025
Registry last updated
Nov 19, 2025

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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