Effectiveness of Clear Aligner Systems in Mixed Dentition Maxillary Transverse Deficiency

May 10, 2026 updated by: Celal Irgin, TC Erciyes University

Comparison of the Effectiveness of Different Clear Aligner Systems in Patients With Maxillary Transverse Deficiency During the Mixed Dentition Period: An In-Vivo Randomized Controlled Clinical Trial

he primary aim of this study is to compare the dentoalveolar and skeletal effects of arch expansion using an in-house clear aligner system, produced chairside with an indirect manufacturing technique, and commercially available clear aligner systems (Invisalign) in patients during the mixed dentition period.

Participants will be allocated into five groups: Group A-In-house aligners (5-day activation protocol), Group B-In-house aligners (2-day activation protocol), Group C-Invisalign First aligners, Group D-Invisalign Palatal Expander, and Group E-untreated control group.

Before treatment, demographic data, dental models, intraoral and extraoral photographs, radiographic images, and clinical measurements will be collected. Skeletal measurements, including maxillary and nasal widths, will be evaluated using posteroanterior cephalometric radiographs. Digital models of the maxilla and mandible will be obtained using an intraoral scanner and used for dental measurements before and after treatment.

Secondary outcomes include evaluation of facial soft tissue changes using stereophotogrammetry (3DMD), assessment of white spot lesions using quantitative light-induced fluorescence (QLF), and analysis of patient compliance using the Orthodontic Patient Cooperation Scale. In addition, changes in body mass index (BMI), maxillary-mandibular transverse discrepancies, and appliance wear time will be evaluated.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

75

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)
    • Kayseri
      • Talas, Kayseri, Turkey (Türkiye), 38039
        • Erciyes University Faculty of Dentistry

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 in the early mixed dentition period;
  • Maxillary intermolar width ≤ 31 mm;
  • Presence of at least 5 mm transverse discrepancy between the maxillary and mandibular arches;
  • Normal vertical growth pattern (Sn-GoGn: 32 ± 6°);
  • Eruption of permanent first molars and central incisors;
  • Presence of at least two primary posterior teeth in each quadrant;
  • Posterior teeth with a clinical crown height of at least 4 mm;
  • Patients aged between 7 and 10 years;
  • Absence of any craniofacial anomalies;
  • Good oral hygiene status; Healthy periodontal tissues.

Exclusion Criteria:

  • Patients with the loss of more than one primary tooth
  • Presence of stainless steel crowns on the maxillary permanent first molars, primary first molars, or primary second molars
  • Patients with systemic or syndromic conditions
  • Presence of palatal exostoses or morphological anomalies of the palatal surface
  • Presence of active temporomandibular joint disorders
  • Children with poor compliance
  • History of allergy to any dental material
  • Patients with multiple and/or advanced caries, tooth agenesis, or supernumerary teeth
  • Patients with skeletal asymmetry

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: Control Group
Experimental: Invisalign Palatal Expander
Device: Invisalign Palatal Expander Therapy
In patients treated with the Invisalign Palatal Expander (IPE) (Align Technology, Santa Clara, CA), three-dimensional digital models were obtained using an intraoral scanner (iTero Lumina™, Align Technology). Individualized maxillary expansion amounts were prescribed based on clinical objectives. Unlike conventional aligner therapy, the IPE system does not involve full digital treatment simulation; expansion was defined by the planned transverse increase. Following approval, customized IPE appliance sets were manufactured and delivered. Patients were instructed to wear the appliance full-time, including during meals, removing it only for oral hygiene procedures. The activation protocol consisted of appliance changes every 2 days, providing 0.25 mm transverse expansion per stage. After completion of expansion, retention was achieved using Invisalign Palatal Holder appliances fabricated from new digital scans.
Experimental: In-House Aligner (2-Day Protocol)
Device: In-House Clear Aligner Therapy (2-Day Protocol)
In-house clear aligners were fabricated using a fully digital workflow. Digital impressions were obtained with an intraoral scanner (3Shape TRIOS), and maxillary models were processed in CAD software for segmentation and attachment planning. Buccal retention attachments were placed on primary canines, primary molars, and permanent first molars. Maxillary models were digitally expanded in 0.2 mm increments per stage, generating sequential STL files. Models were 3D-printed and thermoformed to fabricate aligners, which were then trimmed, polished, and labeled. Patients received five aligners at each visit and were instructed to change them every 2 days. Follow-up visits were scheduled at 10-day intervals. At each visit, treatment progress was assessed, and the next series of aligners was provided.
Experimental: In-House Aligner (5-Day Protocol)
Device: In-House Clear Aligner Therapy (5-Day Protocol)
In-house clear aligners were fabricated using a fully digital workflow. Digital impressions were obtained with an intraoral scanner (3Shape TRIOS), and maxillary models were processed in CAD software for segmentation and attachment planning. Buccal retention attachments were placed on primary canines, primary molars, and permanent first molars to enhance retention and support transverse expansion. Models were digitally expanded in 0.2 mm increments per stage and converted into sequential STL files. These models were 3D-printed (Asiga MAX UV) and thermoformed (MINISTAR S) to produce aligners. The appliances were trimmed, polished, and labeled with sequence numbers. Patients received five aligners per visit and were instructed to change them every 5 days. Follow-up visits were scheduled at 25-day intervals, during which treatment progress was evaluated and new aligners were delivered.
Active Comparator: Invisalign First Aligner
Device: Invisalign First Aligner Therapy
In patients treated with Invisalign First (Align Technology, Santa Clara, CA), three-dimensional digital models were obtained using an intraoral scanner (3Shape TRIOS). Intraoral, extraoral photographs and radiographs were collected and uploaded to the ClinCheck digital treatment planning platform. Individualized treatment objectives were defined, and expansion was planned without concurrent tooth movement to isolate maxillary transverse effects. After achieving the desired expansion, comprehensive orthodontic treatment was continued. Virtual treatment plans were reviewed and revised when necessary before approval. Attachments were placed on posterior teeth to enhance retention and support expansion. Enamel surfaces were etched, bonded, and light-cured using standard orthodontic protocols. Patients were instructed to wear aligners 20-22 hours daily,and aligners were replaced every 5 days.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Maxillary Transverse Dentoalveolar Dimension
Time Frame: 20 weeks
20 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
White spot lesion incidence
Time Frame: 20 weeks
20 weeks

Collaborators and Investigators

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

Sponsor

TC Erciyes 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)

May 26, 2025

Primary Completion (Estimated)

May 1, 2026

Study Completion (Estimated)

July 1, 2026

Study Registration Dates

First Submitted

May 3, 2026

First Submitted That Met QC Criteria

May 10, 2026

First Posted (Actual)

May 14, 2026

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 10, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025/189

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

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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