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

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

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.

Study Overview

• Status: Completed
• Conditions: Malocclusion; Alveolar Bone Loss; Dental Crowding
• Intervention / Treatment: Device: Fixed orthodontic appliance; Device: Clear aligners

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt, 11865
    • Faculty of Oral and Dental Medicine, Future University in Egypt (Department of Orthodontics)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Fixed appliances (Group FA); Conventional pre-adjusted edgewise fixed appliance (0.022-inch slot, MBT prescription) bonded from first molar to first molar; levelling and alignment with a sequence of nickel-titanium and stainless-steel archwires over approximately six months.	Device: Fixed orthodontic appliance; 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)
Experimental: Clear aligners (Group CA); Three-dimensionally printed, thermoformed clear aligners with bonded attachments and interproximal reduction as indicated; worn ~22 hours/day and changed per the digital staging, with clinical review every four weeks over approximately six months	Device: Clear aligners; 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in alveolar bone level	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.	Baseline (T0) and end of alignment phase (T3)) (approximately 6 months)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in alveolar bone thickness	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.	Baseline (T0) and end of alignment phase (≈ 6 months)
Change in mandibular incisor inclination (torque)	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.	Baseline (T0) and end of alignment phase (≈ 6 months)
Rate of alignment (Little's Irregularity Index)	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.	Baseline (T0), 8 weeks (T1), 16 weeks (T2) and end of alignment (T3, ≈ 24 weeks / 6 months)

Collaborators and Investigators

• Sponsor: Future University in Egypt
• Investigators: Principal Investigator: ahmed mohamed hesham elzoghary, Faculty of Oral and Dental Medicine, Future University in Egypt

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2024
• Primary Completion (Actual): July 25, 2025
• Study Completion (Actual): April 15, 2026

Study Registration Dates

• First Submitted: July 15, 2026
• First Submitted That Met QC Criteria: July 15, 2026
• First Posted (Actual): July 21, 2026

Study Record Updates

• Last Update Posted (Actual): July 21, 2026
• Last Update Submitted That Met QC Criteria: July 15, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: adults; cone-beam computed tomography; torque; clear aligners; fixed orthodontic appliances; Little's Irregularity Index; alveolar bone level; alveolar bone thickness; incisor inclination; rate of alignment; non-extraction treatment
• Additional Relevant MeSH Terms: Bone Resorption; Bone Diseases; Musculoskeletal Diseases; Periodontal Atrophy; Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Tooth Diseases; Behavior; Spatial Behavior; Alveolar Bone Loss; Malocclusion; Crowding; Dentistry; Orthodontic Appliances; Orthodontics; Orthodontic Appliances, Fixed
• Other Study ID Numbers: FUE.REC (18)/7-2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No