Leaf Expander Versus Hyrax Expander in Mixed Dentition Patients With Posterior Crossbite.

March 16, 2026 updated by: Noura Mohamed Hamza Hassan Saleh, Cairo University

Evaluation of the Effects of the Leaf Expander Versus Hyrax Expander in Mixed Dentition Patients With Posterior Crossbite: A Randomized Clinical Trial.

Design: Two-arm parallel randomized clinical trial in mixed dentition (6-12 years).

Arms: (1) 9 mm, 900 g leaf expander; (2) 9 mm Hyrax expander. Follow-up: From appliance insertion → completion of intended expansion → 6-month retention.

Primary outcome: Pain perception during the first 7 days post-insertion (daily patient-reported scale).

Secondary outcomes: Skeletal and dental changes on CBCT.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Participants receive a banded maxillary expansion appliance cemented to maxillary first permanent molars, assigned to:

Leaf expander arm: Nickel-titanium leaf-spring expander, 9 mm screw, delivering force of ~900 g.

Hyrax expander arm: Conventional tooth-borne jackscrew expander, 9 mm screw. Standard activation: two turns per week.

Retention: Both appliances kept passively in situ for 6 months of retention following achievement of planned expansion.

Study Type

Interventional

Enrollment (Estimated)

30

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

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:

  • Male and female patients
  • Mixed dentition stage
  • Unilateral or bilateral posterior crossbite.
  • Patients in prepubertal stage with cervical vertebral maturation stage 1-3.
  • Fully erupted maxillary and mandibular permanent first molars.
  • Skeletal class I or II.

Exclusion Criteria:

  • Previous orthodontic treatment.
  • Missing teeth.
  • Inadequate oral hygiene.
  • Patients with bad oral habits.
  • Patients with medical conditions.
  • Patients with cleft lip and palate.

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Banded Leaf expander supported on the maxillary first permanent molars
9mm leaf expander delievering 900 gm force will be supported on the upper first permanent molars with the appliance arm extending to the canines
Device: The Leaf expander
The Leaf expander incorporates Nickel Titanium springs that will not require the patients' home activation
Active Comparator: Banded Hyrax expander supported on the maxillary first permanent molars
9mm Hyrax expander will be supported on the upper first permanent molars with the appliance arm extending to the canines
Device: Hyrax expander
Hyrax expander incorporates a screw that requires the patients' home activation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain perception
Time Frame: first week after appliance insertion
Pain perception during the first week after insertion using Wong-Becker faces scale with minimum value of zero and maximum value of ten, ten score represents the worst pain percieved.
first week after appliance insertion

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
skeletal expansion
Time Frame: 6 months post expansion
skeletal expansion using Cone Beam Computed Tomography skeletal expansion: linear distances of the midpalatal suture opening measured in mm between the pre- and post-axial cuts of the CBCT
6 months post expansion
dental tipping
Time Frame: 6 months post-expansion
Angular measurement of upper first molars angulation measured in degrees between pre- and post-coronal cuts of the CBCT
6 months post-expansion

Collaborators and Investigators

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

Sponsor

Cairo 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)

October 1, 2025

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

March 1, 2027

Study Registration Dates

First Submitted

November 21, 2025

First Submitted That Met QC Criteria

December 23, 2025

First Posted (Actual)

December 24, 2025

Study Record Updates

Last Update Posted (Actual)

March 18, 2026

Last Update Submitted That Met QC Criteria

March 16, 2026

Last Verified

October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 24619942

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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