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NCT Number: NCT07716007

Bone Level Changes Using Clear Aligners Compared to Fixed Appliances in Non-Extraction Treatment of Adults

This study compares two common ways of straightening teeth in adults who have mild-to-moderate crowding of the lower front teeth and do not need any teeth removed: clear aligners and traditional fixed braces.

The main aim is to find out whether the two methods differ in how they affect the bone that surrounds the teeth. Using three-dimensional X-ray scans (cone-beam CT) and digital models of the teeth taken before and during treatment, the researchers measure the level and thickness of the bone around the lower front teeth, the tilt (inclination) of the lower front teeth, and how quickly the crowding is corrected.

Adults are randomly assigned to receive either clear aligners or fixed braces, and the same measurements are compared between the two groups over about six months.

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Key information

Conditions

Dental Crowding Alveolar Bone Loss Behavior Bone Diseases Bone Resorption Crowding Malocclusion Mouth Diseases Musculoskeletal Diseases Periodontal Atrophy Periodontal Diseases Spatial Behavior Stomatognathic Diseases Tooth Diseases

Age range

18 year–25 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Faculty of Oral and Dental Medicine, Future University in Egypt (Department of Orthodontics)

Cairo, 11865, Egypt

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Adults 18-25 years of age, of both sexes.
  • Mild-to-moderate mandibular anterior crowding (2-6 mm).
  • Angle Class I molar relationship with normal overjet (1-3 mm) and overbite (1-2 mm).
  • Full permanent dentition with a healthy periodontium.
  • Normal anteroposterior and vertical skeletal pattern.

Exclusion criteria

  • Any local or systemic condition, or trauma, capable of affecting craniofacial growth and development.
  • History of previous orthodontic or interceptive treatment.
  • Loss of periodontal attachment.
  • Craniofacial anomalies, facial asymmetry or skeletal discrepancy.

Treatment and study plan

Fixed orthodontic appliance

Device

Brackets bonded first-molar-to-first-molar; alignment sequence 0.014" NiTi → 0.016" NiTi → 0.016 × 0.022" NiTi → 0.017 × 0.025" stainless steel. Interproximal reduction performed on assigned contacts where indicated.

Other names: Conventional labial brackets, pre-adjusted edgewise appliance (0.022 MBT)

Clear aligners

Device

Digital intraoral scan and staging (3Shape Ortho Analyzer); 3D-printed models thermoformed into aligners; attachments bonded where planned; sequential aligners worn ~22 h/day. Interproximal reduction per contact from canine-to-canine is done.

Other names: sequential clear aligners, Thermoformed removable aligners

Primary outcomes

  1. Change in alveolar bone level

    Time frame: Baseline (T0) and end of alignment phase (T3)) (approximately 6 months)

    Change (mm) in the distance from the cemento-enamel junction to the alveolar crest on the labial and lingual aspects of the mandibular central incisors, lateral incisors and canines, measured on CBCT (OnDemand software), calculated as the difference between baseline and end-of-alignment values.

Secondary outcomes

  1. Change in alveolar bone thickness

    Time frame: Baseline (T0) and end of alignment phase (≈ 6 months)

    Change (mm) in labial and lingual alveolar bone thickness measured at 3 mm and 6 mm from the CEJ and at the root apex of the mandibular central incisors, lateral incisors and canines on CBCT (OnDemand software), from baseline to end of alignment.

  2. Change in mandibular incisor inclination (torque)

    Time frame: Baseline (T0) and end of alignment phase (≈ 6 months)

    Change (degrees) in the inner angle between the long axis of each mandibular central incisors, lateral incisors and canines and the mandibular plane, measured on the sagittal view of CBCT (Invivo/Anatomage software), from baseline to end of alignment.

  3. Rate of alignment (Little's Irregularity Index)

    Time frame: Baseline (T0), 8 weeks (T1), 16 weeks (T2) and end of alignment (T3, ≈ 24 weeks / 6 months)

    Reduction in mandibular anterior crowding quantified by Little's Irregularity Index (mm) - the sum of the displaced anatomic contact points from canine to canine - measured on serial digital models; the change across time points and the percentage improvement from baseline describe the rate of alignment.

Sponsors and collaborators

Lead sponsor

Future University in Egypt

Other

Registry information

Official study title

Evaluation of Bone Level Changes Using Clear Aligners Compared to Fixed Appliances in Non-extraction Treatment of Adult Patients: A Randomized Clinical Trial

Important dates

Study start
2024
Primary completion
2025
Study completion
2026
First posted
Jul 21, 2026
Registry last updated
Jul 21, 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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