NCT07404488

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

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.

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 36 (actual)
• Sponsor: University of Roma La Sapienza · Academic / Other
• Sex: All
• Age: 10 Years – 15 Years
• Healthy volunteers: Not accepted

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.

Detailed description

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.

Conditions

• Orthodontic Appliance

Interventions

Type	Name	Description
DEVICE	Miniscrew supported expander application	Two palatal miniscrews with custom bone-borne expansion framework (device transmits forces to palatal bone; no tooth bands).
DEVICE	4 miniscrews supported rapid maxillary expansion application	Four palatal miniscrews with custom bone-borne expansion appliances.
DEVICE	Conventional tooth-borne Hyrax expander (comparator)	Hyrax-type tooth-borne expander with bands cemented on upper first molars (Hyrax click 10 mm).

Timeline

• Start date: 2021-11-01
• Primary completion: 2024-09-01
• Completion: 2024-09-01
• First posted: 2026-02-11
• Last updated: 2026-02-11

Locations

1 site across 1 country: Italy