Comparison of Two Miniscrew Bone-borne Expanders (2 vs 4 Screws) Versus Conventional Hyrax Expander in Adolescents

NCT07404488 | Completed

• 1 other identifier: URomLS_RME
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

Rapid maxillary expansion (RME) is used to correct transverse deficiencies of the maxilla. This randomized controlled trial compares three RME devices in adolescents (age 10-15) with at least 8 mm maxillary transverse deficiency: (1) bone-borne expander supported by two palatal miniscrews, (2) bone-borne expander supported by four palatal miniscrews, and (3) conventional tooth-borne Hyrax expander. Devices were placed using static computer-guided miniscrew insertion (where applicable). All participants received the same activation protocol to reach 8 mm expansion. Cone-beam CT scans were obtained pre-treatment (T0) and at 6 months post-treatment (T1). The trial assesses skeletal, dentoalveolar, periodontal, and nasal/airway outcomes. Enrollment: 36 subjects. Study sites: Sapienza University of Rome.

Conditions

Orthodontic Appliance

Outcome Measures

Primary Outcomes (1)

• Change in maxillary basal width (MaxBas) from baseline (T0) to 6 months post-treatment (T1)

  Measurement method: CBCT (Simplant software) distance between alveolar/basal points (points 5-6 as per Podesser/Garib protocol).

  at 6 months

Study Arms (3)

Arm 1 (Group A) - Two-miniscrew bone-borne expander

EXPERIMENTAL

one-borne rapid maxillary expander anchored on two palatal miniscrews inserted in paramedian palatal vault (near first-second premolar area). Miniscrews: self-tapping titanium (Benefit system; PSM Medical Solutions). Placement planned via CBCT-guided CAD/CAM surgical guide (Easy Driver). Activation protocol: Hyrax click 10 mm screw: 4 quarter-turns at placement then 3 quarter-turns/day for 12 days (0.20 mm/turn) until \~8 mm expansion.

Device: Miniscrew supported expander application

Arm 2 (Group B) - Four-miniscrew bone-borne expander

EXPERIMENTAL

Bone-borne rapid maxillary expander anchored on four palatal miniscrews (two paramedian + two parapalatine). Same guided insertion workflow and activation protocol as Group A.

Device: 4 miniscrews supported rapid maxillary expansion application

Arm 3 (Group C) - Conventional tooth-borne Hyrax expander

ACTIVE COMPARATOR

Tooth-borne Hyrax expander banded on upper first permanent molars (conventional Hyrax). Same activation protocol as Groups A/B.

Device: Conventional tooth-borne Hyrax expander (comparator)

Interventions

Conventional tooth-borne Hyrax expander (comparator) DEVICE

Hyrax-type tooth-borne expander with bands cemented on upper first molars (Hyrax click 10 mm).

Arm 3 (Group C) - Conventional tooth-borne Hyrax expander

Miniscrew supported expander application DEVICE

Two palatal miniscrews with custom bone-borne expansion framework (device transmits forces to palatal bone; no tooth bands).

Arm 1 (Group A) - Two-miniscrew bone-borne expander

4 miniscrews supported rapid maxillary expansion application DEVICE

Four palatal miniscrews with custom bone-borne expansion appliances.

Arm 2 (Group B) - Four-miniscrew bone-borne expander

Eligibility Criteria

• Age: 10 Years - 15 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Age 10 to 15 years (under 16 at enrollment).
• Late mixed or permanent dentition.
• Maxillary transverse deficiency ≥ 8 mm (unilateral or bilateral).
• Parent/guardian able to provide written informed consent; participant assent where applicable.

You may not qualify if:

• Poor oral hygiene.
• Prior orthodontic treatment.
• Craniofacial syndromes.
• Cleft lip and/or palate.
• Genetic or congenital diseases likely to affect craniofacial growth or bone quality.
• Inability/unwillingness to attend scheduled follow-up visits.

Sponsors & Collaborators

• University of Roma La Sapienza: lead

Study Sites (1)

Sapienza University of Rome

Rome, Rm, 00161, Italy

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor, DDS, PhD

Study Record Dates

• First Submitted: February 4, 2026
• First Posted: February 11, 2026
• Study Start: November 1, 2021
• Primary Completion: September 1, 2024
• Study Completion: September 1, 2024
• Last Updated: February 11, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)