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NCT Number: NCT07404488

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

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.

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Key information

Conditions

Orthodontic Appliance

Age range

10 year–15 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Sapienza University of Rome

Rome, Rm, 00161, Italy

About this study

This is a prospective, randomized, parallel-group clinical trial performed at the Department of Oral and Maxillofacial Sciences, Sapienza University of Rome (Nov 2021 - Sep 2024). Inclusion criteria included age under 16 years, late mixed or permanent dentition, and maxillary transverse deficiency ≥ 8 mm. Exclusion: poor oral hygiene; previous orthodontic treatment; craniofacial syndromes; cleft lip/palate; genetic/congenital diseases. After consent, eligible participants (N=36) were randomized (1:1:1) to: Group A - two-miniscrew bone-borne expander (paramedian screws near 1st-2nd premolar region); Group B - four-miniscrew bone-borne expander (two paramedian + two parapalatine); Group C - Hyrax tooth-borne expander banded to upper first molars. Miniscrews (Benefit system; PSM Medical Solutions) were placed using a CAD-CAM surgical guide planned from CBCT and digital models (Easy Driver). Activation: Hyrax click 10 mm screw; four quarter-turns at insertion then three quarter-turns/day for 12 days (0.20 mm/turn; ~0.6 mm/day) until 8 mm achieved. CBCT scan acquisition: Scanora 3Dx (Soredex). Measurements performed on Simplant v17 on defined landmarks (MaxBas, MaxAlv, MaxAlvPre, Ns, ZigMax, IntermCo, IntermoAp, molar angles, periodontal bone thickness measures, nasopalatine foramen width). Primary outcome: change in maxillary basal width (MaxBas) T0 to T1 measured on CBCT.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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.

Treatment and study plan

Miniscrew supported expander application

Device

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

4 miniscrews supported rapid maxillary expansion application

Device

Four palatal miniscrews with custom bone-borne expansion appliances.

Conventional tooth-borne Hyrax expander (comparator)

Device

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

Primary outcomes

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

    Time frame: at 6 months

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

Sponsors and collaborators

Lead sponsor

University of Roma La Sapienza

Other

Registry information

Official study title

Prospective Randomized Controlled Study Comparing Dentoalveolar, Skeletal, Periodontal and Nasal/Airway Effects of a Two-miniscrew Bone-borne Expander, a Four-miniscrew Bone-borne Expander, and a Conventional Tooth-borne Hyrax Expander in Adolescents.

Important dates

Study start
2021
Primary completion
2024
Study completion
2024
First posted
Feb 11, 2026
Registry last updated
Feb 11, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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