Efficacy of Skeletally Anchored Modified Leaf Expander in Maxillary Molar Distalization

NCT07534072 | Completed

• 1 other identifier: #R-ORTH-08-25-3220
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Background: Distalization in orthodontics is one of conservative treatment modalities that result in gaining space especially in dental orthodontic cases of class ΙΙ molar relationship. Aim: This study aimed to compare the distalization effects of the skeletally anchored modified Leaf Expander versus the skeletally anchored modified conventional Hyrax Expander. Patients and Methods: Thirty patients (15-18 years) requiring maxillary molar distalization were randomly allocated into two groups (n = 15 each). Group 1 received the modified skeletally anchored self-activated Leaf Expander, and Group 2 received the modified skeletally anchored conventional Hyrax Expander. Pre- and post-distalization lateral cephalometric radiographs and digital dental models were analyzed for skeletal, dental, and arch dimensional changes. Treatment duration and adverse events were also recorded. Statistical analysis included paired t-tests and independent t-tests, with Bonferroni correction (α = 0.0045) applied for multiple comparisons. Effect sizes (Cohen's d) were calculated to assess clinical relevance. .

Conditions

Orthodontic Patients

Keywords

Maxillary molar, Distalization

Outcome Measures

Primary Outcomes (5)

• Arch length

  Arch length in millimetres

  six months

• Inter-canine width

  Inter-canine width in millimetres

  six months

• Inter-first premolar width

  Inter-first premolar width in millimetres

  six months

• Inter-second premolar width

  Inter-second premolar width in millimetres

  six months

• Inter-first molar width

  Inter-first molar width in millimetres.

  six months

Secondary Outcomes (8)

• SNA angle

  six months

• SNB angle

  six months

• ANB angle

  six months

• FH-MP angle

  six months

• overjet

  six months

Study Arms (2)

skeletally anchored Modified Leaf Expander

ACTIVE COMPARATOR

The Leaf Expander (Leaf Expander®, Leone SpA, Sesto Fiorentino, Florence, Italy) resembles a rapid palatal expander but incorporates Nickel Titanium MEMORIA leaf springs that provide continuous force. It consists of two body parts connected by rods over which the leaf springs slide. The springs are held compressed by staples on each side of the body parts. The superelastic nickel-titanium leaf springs deliver a controlled, continuous force once the staples are removed. Two types of Leaf Expanders are available, delivering either 450 or 900 grams of force; the 450-gram/ 6 mm in length version was used in this study.

Device: skeletally anchored Modified Leaf Expander

Skeletally anchored inverted hyrax

EXPERIMENTAL

Fabrication of the Modified Palatally Anchored Expander Appliance The positions of the screws for skeletal anchorage were determined on the model within a safe square on the anterior palatal area. Four lines were drawn (9): * The first line, 8 mm distal to the incisive papilla, marked the anterior boundary. * The second line, parallel to the first, passed through the distal surfaces of the second premolars to mark the posterior boundary. * Two additional lines, each 8 mm lateral to the median palatal raphe, were drawn perpendicular to the first two lines.

Device: skeletally anchored Modified Leaf Expander

Interventions

skeletally anchored Modified Leaf Expander DEVICE

Intervention Elastic separators were placed mesial and distal to the maxillary first molars bilaterally for 3 days to create space for band placement (19). Appropriate bands were selected and fitted to the molars. An alginate impression was taken with the bands in place, then the bands were removed and repositioned in the impression. The impression was poured in stone to fabricate the working model. Fabrication of the Modified Palatally Anchored Expander Appliance The positions of the screws for skeletal anchorage were determined on the model within a safe square on the anterior palatal area. Four lines were drawn (9): * The first line, 8 mm distal to the incisive papilla, marked the anterior boundary. * The second line, parallel to the first, passed through the distal surfaces of the second premolars to mark the posterior boundary. * Two additional lines, each 8 mm lateral to the median palatal raphe, were drawn perpendicular to the first two lines. The four-point support expander was

Also known as: Modified Conventional Hyrax

Skeletally anchored inverted hyrax; skeletally anchored Modified Leaf Expander

Eligibility Criteria

• Age: 15 Years - 18 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Class II molar relation.
• Patients aged between 15 and 18 years.
• Overjet less than 6 mm
• ANB angle between 5° and 7°.
• Non-extraction treatment plan with molar distalization.
• Horizontal or normal growth pattern with symmetrical, balanced facial appearance.
• Minimal crowding in the mandibular arch.

You may not qualify if:

• Congenitally missing teeth
• Congenital anomalies
• Systemic diseases
• Previous orthodontic treatment

Sponsors & Collaborators

• Al-Azhar University: lead

Study Sites (1)

Al- Azhar University

Cairo, Nasr City, 4450113, Egypt

Location

Study Officials

• Nouran Eissa, Ass. lect

  Tanta University

  STUDY CHAIR

• Mohamed Elbialy, Lecturer

  El mansoura University

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate professor, Department of orthodontics - Faculty of Dental medicine (Boys, Cairo) - Al-Azhar University

Study Record Dates

• First Submitted: April 2, 2026
• First Posted: April 16, 2026
• Study Start: January 15, 2024
• Primary Completion: July 14, 2025
• Study Completion: August 12, 2025
• Last Updated: April 16, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

EG (1)