Effects of Invisalign Palatal Expander vs Rapid Palatal Expander With Facemask in Growing Class III Patients

March 16, 2026 updated by: Mahidol University

Effects of the Invisalign® Palatal Expander (IPE) vs. Rapid Palatal Expander With Facemask in Growing Skeletal Class III Patients: A CBCT Randomized Clinical Trial

The goal of this clinical trial is to compare two types of palatal expanders used with a facemask in children who have skeletal Class III and a narrow upper jaw. The study will compare the Invisalign Palatal Expander (IPE) and the Rapid Palatal Expander (RPE). Researchers want to learn how these devices affect jaw bones and tooth position. They also want to learn about children's and parents' experiences during treatment.

The main questions this study aims to answer are:

Do IPE and RPE widen the upper jaw differently?

Do they cause different changes in tooth position?

How do children and parents describe their treatment experience?

Participants will be children aged 8 to 12 years who have skeletal Class III and a narrow upper jaw. Children with craniofacial conditions, previous upper jaw expansion, or medical conditions that prevent orthodontic treatment will not take part. Parents and children must give consent before joining the study.

Participants will:

Be assigned to receive either IPE or RPE

Expand the upper jaw to 7 mm (0.25 mm per day)

After expansion, wear a facemask for at least 12 hours per day for 6 to 8 months

Have cone-beam computed tomography (CBCT) scans taken before expansion, after expansion, and after facemask treatment

Take part in an interview with a parent after expansion

Researchers will use CBCT images to measure changes in jaw bones and tooth position. The main outcomes are changes in jaw bones and tooth position. Secondary outcomes include children's and parents' experiences during treatment.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

24

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

  • Thailand
      • Bangkok, Thailand, 10700
        • Faculty of Dentistry, Mahidol University
        • Contact:
        • Contact:
          • Chaisomsukrudee, DDS
          • Phone Number: +662007813

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 aged between 8 and 12 years
  • Patients in the mixed dentition or early permanent stage have at least three stable teeth per quadrant, good oral hygiene, and healthy periodontal tissues
  • Patients with maxilla-mandibular discrepancies; skeletal class III is indicated by an ANB angle < 0 degrees or a Wits appraisal value that is negative, and Maxillary constriction is characterized by posterior crossbite teeth or having a maxillary width below the norm value.

Exclusion Criteria:

  • Patients with craniofacial anomalies such as cleft lip and palate
  • Patient with a prior history of maxillary expansion.
  • Patients who have systemic conditions that contraindicate orthodontic treatment.

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
Experimental: Invisalign Palatal Expander (IPE) group
Device: Invisalign Palatal Expander (IPE)
Participants will be treated with an Invisalign palatal expander. Participants will be instructed to wear the appliance full-time, except when brushing and flossing their teeth, and to change the device daily (0.25 mm) until the planned transverse width (7 mm.) is achieved.
Active Comparator: Rapid Palatal Expander (RPE) group
Device: Rapid Palatal Expander (RPE)
Participants will be treated with a bonded RPE. Their parents are instructed to activate the screw once per day (0.25 mm) until the expansion screw reaches 7 mm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maxillary skeletal change
Time Frame: T0: Baseline (Day 0) - before initiation of maxillary expansion T1: Post-expansion - after completion of 7 mm expansion with RPE or IPE T2: Post-protraction - after 6 months of active maxillary protraction
  • Anterior and posterior midpalatal suture width
  • Anterior apical base width inferior
  • Anterior apical base width superior
  • Posterior apical base width
  • Anterior width at mid-alveolar level
  • Posterior width at alveolar crest level
T0: Baseline (Day 0) - before initiation of maxillary expansion T1: Post-expansion - after completion of 7 mm expansion with RPE or IPE T2: Post-protraction - after 6 months of active maxillary protraction
Maxillary dental change
Time Frame: T0: Baseline (Day 0) - before initiation of maxillary expansion T1: Post-expansion - after completion of 7 mm expansion with RPE or IPE T2: Post-protraction - after 6 months of active maxillary protraction
  • Intermolar width at occlusal surface
  • Intermolar width at palatal root apices
  • Right first molar angulation
  • Left first molar angulation
T0: Baseline (Day 0) - before initiation of maxillary expansion T1: Post-expansion - after completion of 7 mm expansion with RPE or IPE T2: Post-protraction - after 6 months of active maxillary protraction

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Functional and perceptual experiences and parental involvement associated with the use of Rapid Palatal Expander (RPE) and Invisalign Palatal Expander (IPE).
Time Frame: Single assessment at 28 days (± 5 days) after appliance insertion
The functional and perceptual experiences of pediatric patients and their parents, as well as parental involvement in appliance management, will be evaluated through semi-structured face-to-face interviews. Interviews will take place at the Orthodontic Clinic, Faculty of Dentistry, Mahidol University, using a topic guide developed from the study conceptual framework. The interviews will explore appliance-related factors, functional impacts on the child (pain, speech, mastication, and oral hygiene), emotional and perceptual responses of both children and parents, parental involvement in appliance management, treatment compliance, and perceived treatment outcomes. Each interview will last approximately 30 minutes, with audio recording and field notes used for qualitative analysis.
Single assessment at 28 days (± 5 days) after appliance insertion

Collaborators and Investigators

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

Sponsor

Mahidol University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

March 1, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

October 1, 2027

Study Registration Dates

First Submitted

March 2, 2026

First Submitted That Met QC Criteria

March 16, 2026

First Posted (Actual)

March 20, 2026

Study Record Updates

Last Update Posted (Actual)

March 20, 2026

Last Update Submitted That Met QC Criteria

March 16, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • MU-DT/PY-IRB 2025/095.2312

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

IPD will not be shared due to information that could compromise the privacy of research participants.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

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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