This controlled prospective clinical trial aims to evaluate the effectiveness of different maxillary expansion methods in children with maxillary transverse deficiency. A total of 60 participants will be included: 20 patients will receive Invisalign Palatal Expander (IPE), 20 will receive acrylic cap splint Rapid Maxillary Expansion (RME), and 20 will serve as an untreated control group. Three-dimensional (3D) intraoral and extraoral scans will be taken at the end of expansion, at 3 months, and at 6 months. Primary outcomes include maxillary arch width, first molar angulation, palatal surface area, and palatal volume. Secondary outcomes include soft tissue changes in the facial region. This study provides a direct comparison between a traditional and a modern digital expansion method, generating evidence for clinical decision-making in pediatric orthodontics.

Maxillary transverse deficiency is a common craniofacial problem that often presents with posterior crossbite and dental crowding. Rapid Maxillary Expansion (RME) achieves sutural separation and bone remodeling, typically activated at 0.5 mm per day. Invisalign® Palatal Expander (IPE) is a modern digital system using 3D printing to produce removable nylon expanders adapted to palatal curvature, with 0.25 mm activations, simplifying oral hygiene and eliminating screw activation.

This controlled prospective clinical trial will recruit 60 children with maxillary transverse deficiency. Participants will be assigned to three groups: IPE (n=20), RME (n=20), and untreated control (n=20). Intraoral scans will be obtained at the end of expansion, at 3 months, and at 6 months to create three-dimensional digital models. Maxillary dental arch widths, first molar angulations, palatal surface areas, and volumes will be measured. Extraoral 3D facial scans will evaluate soft tissue changes, including nasal tip, alar width, and interzygomatic distance.

Statistical analyses will be performed using SPSS, applying t-tests for intra- and inter-group comparisons. The study aims to provide comparative data on a traditional (RME) and a contemporary digital (IPE) maxillary expansion method. No prior studies have directly compared these two techniques in children.

Inclusion Criteria:

• Children aged 6-12 years
• Good oral hygiene and adequate patient cooperation
• No previous orthodontic expansion treatment

Exclusion Criteria:

• Systemic diseases affecting growth, bone metabolism, or craniofacial development
• Craniofacial syndromes or congenital anomalies
• Severe behavioral or cooperation problems
• Previous orthodontic or orthopedic maxillary expansion
• Patients undergoing medications that affect bone metabolism

De-identified individual participant data (IPD) from this study, including intraoral and extraoral 3D scans, radiographs will be made available to other researchers upon reasonable request. All data will be anonymized to protect patient confidentiality. Access requests will be reviewed by the principal investigator, and researchers will be required to sign a data use agreement to ensure appropriate and secure use of the data.

Data will be available beginning 6 months after publication of the study results, for a period of 5 years.

De-identified individual participant data (IPD), including intraoral and extraoral 3D scans, radiographs along with the study protocol, statistical analysis plan, and analytic code, will be available to qualified researchers. Access will be granted upon reasonable request, reviewed by the principal investigator. Researchers must submit a proposal and sign a data use agreement to ensure confidentiality and appropriate use of the data. Data will be shared through a secure repository after publication of the primary results.