Skeletal Class III MalocclusionNCT07485478
Effects of Invisalign Palatal Expander vs Rapid Palatal Expander With Facemask in Growing Class III Patients
A study testing Invisalign Palatal Expander (IPE) and Rapid Palatal Expander (RPE) in people with Skeletal Class III Malocclusion and Transverse Maxillary Deficiency, run by Mahidol University at 1 site in Thailand.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 8 to 12 years
- Conditions the study is for
- Skeletal Class III Malocclusion, Transverse Maxillary Deficiency
- What is being tested?
- Invisalign Palatal Expander (IPE) and Rapid Palatal Expander (RPE)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteThailand
- Study dates
- Mar 2026to Oct 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 8 to 12 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Thailand1 site
Faculty of Dentistry, Mahidol University
Bangkok, 10700
Nakornnoi, DDS PhD, +662007813, theerasak.nak@mahidol.ac.th
Chaisomsukrudee, DDS, +662007813
About this study
Official title: 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:
Read more
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.
- Being tested
- Invisalign Palatal Expander (IPE), Rapid Palatal Expander (RPE)
- Keywords
- Invisalign Palatal Expander, Rapid Palatal Expansion, Facemask, CBCT, Retrognathic maxilla
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Invisalign Palatal Expander (IPE)Device
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.
Rapid Palatal Expander (RPE)Device
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.
| Study group | Role | What they receive |
|---|---|---|
| Invisalign Palatal Expander (IPE) group | Experimental | Not described Receives: Device: Invisalign Palatal Expander (IPE) |
| Rapid Palatal Expander (RPE) group | Active comparator | Not described Receives: Device: Rapid Palatal Expander (RPE) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maxillary skeletal change
- 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
Measured: 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
- Intermolar width at occlusal surface
- Intermolar width at palatal root apices
- Right first molar angulation
- Left first molar angulation
Measured: 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 outcomes (1)
Functional and perceptual experiences and parental involvement associated with the use of Rapid Palatal Expander (RPE) and Invisalign Palatal Expander (IPE).
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.
Measured: Single assessment at 28 days (± 5 days) after appliance insertion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Mar 2026
- Study startMar 2026 (estimated)
- Primary completionJun 2027 (estimated)
- Study completionOct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Skeletal Class III MalocclusionStudies of the same condition, open and under way.
- More trials run by Mahidol UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mahidol University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07485478
- Sponsor's protocol ID
- MU-DT/PY-IRB 2025/095.2312
- Status last verified
- Mar 2026
- First submitted
- 2 Mar 2026
- Last updated
- 20 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No: IPD will not be shared due to information that could compromise the privacy of research participants.
Publications
Weissheimer A, de Menezes LM, Mezomo M, Dias DM, de Lima EM, Rizzatto SM. Immediate effects of rapid maxillary expansion with Haas-type and hyrax-type expanders: a randomized clinical trial. Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):366-76. doi: 10.1016/j.ajodo.2010.07.025.
PubMed 21889081
Study at a glance
From the registry record, last updated by the sponsor on 20 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of the Invisalign® Palatal Expander (IPE) vs. Rapid Palatal Expander With Facemask in Growing Skeletal Class III Patients: A CBCT Randomized Clinical Trial
- ClinicalTrials.gov ID
- NCT07485478
- Acronym / sponsor ID
- MU-DT/PY-IRB 2025/095.2312
- Keywords
- Invisalign Palatal Expander, Rapid Palatal Expansion, Facemask, CBCT, Retrognathic maxilla
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- Mahidol UniversityUniversity, hospital or other
- Study start
- Mar 2026 (estimated)
- Primary completion
- Jun 2027 (estimated)
- Study completion
- Oct 2027 (estimated)
- First posted
- 20 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Invisalign Palatal Expander (IPE) group | Experimental | Device: Invisalign Palatal Expander (IPE) |
| Rapid Palatal Expander (RPE) group | Active comparator | Device: Rapid Palatal Expander (RPE) |
Who may qualify
- Ages
- 8 to 12 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (3 listed)
- 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.
Key exclusion criteria (3 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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. | Device | Invisalign Palatal Expander (IPE) group |
| 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. | Device | Rapid Palatal Expander (RPE) group |
Primary outcome
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
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
1 secondary outcome
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
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Mar 2026.
- Background: PubMed 21889081Weissheimer A, de Menezes LM, Mezomo M, Dias DM, de Lima EM, Rizzatto SM. Immediate effects of rapid maxillary expansion with Haas-type and hyrax-type expanders: a randomized clinical trial. Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):366-76. doi: 10.1016/j.ajodo.2010.07.025.
- Individual participant dataSharing planned: No. IPD will not be shared due to information that could compromise the privacy of research participants.
Related trials for Skeletal Class III Malocclusion
Not yet recruiting
Clinical and Radiographic Evaluation of Low Sagittal Medial Ramus Osteotomy for Treatment of Skeletal Class II and Class III Malocclusion
Skeletal Class II Malocclusion, Skeletal Class III Malocclusion
Enrolling by invitation
Skeletal and Dentoalveolar Effects of Functional Clear Aligner Therapy in Growing Patient With Skeletal Class III Malocclusion
Skeletal Class III Malocclusion
Not yet recruiting
Comparison of Maxillary Protraction Using Tooth-borne Facemask Versus Skeletal Anchorage Chin-plate in Class III Growing Patients
Skeletal Class III Malocclusion
Enrolling by invitationPhase 1
Management of Skeletal Class III Malocclusion With Digital Bonded Reverse Twin Block in Mixed Dentition
Skeletal Class III Malocclusion
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Invisalign Palatal Expander (IPE) and Rapid Palatal Expander (RPE) in people with Skeletal Class III Malocclusion and Transverse Maxillary Deficiency, run by Mahidol University at 1 site in Thailand.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 20 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Thailand. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07485478, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Mar 2026.