Effectiveness of Clear Aligner Systems in Mixed Dentition Maxillary Transverse Deficiency

Summary

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.

Conditions

• Maxillary Transverse Deficiency

Interventions

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.

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.

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.

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.

Sponsors & Collaborators

• TC Erciyes University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

7 Years

Max Age

10 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-05-26

Primary Completion

2026-05-31

Completion

2026-07-31

Countries

• Turkey (Türkiye)

Study Locations