Comparison of Ertty Gap III and Facemask Therapy for Skeletal Class III Correction

NCT07771660 | Completed

• 1 other identifier: ERTTY-FM-CLASSIII-02
• Study Type: interventional
• Target: 42
• Locations: 1 country
• Sites: 1

Brief Summary

This single-center, parallel-group randomized clinical trial compared 2 orthopedic treatment approaches in growing patients with skeletal Class III malocclusion associated predominantly with maxillary deficiency: the Ertty Gap III appliance and facemask therapy. Forty-two participants were randomly allocated in a 1:1 ratio to Ertty Gap III or facemask therapy. The primary objective was to compare the short-term skeletal effects of the 2 treatment protocols, with the ANB angle designated as the primary outcome. Skeletal, dentoalveolar, and soft-tissue outcomes were assessed using standardized lateral cephalometric radiographs obtained before treatment and at treatment completion.

Conditions

Skeletal Class III Malocclusion

Keywords

Skeletal Class III Malocclusion; Maxillary Protraction; Ertty Gap III; Facemask Therapy; Premaxillary-Maxillary Suture; Orthopedic Treatment

Outcome Measures

Primary Outcomes (1)

• Change in ANB Angle

  Change in the ANB angle (degrees) from baseline to completion of orthopedic treatment, assessed on standardized lateral cephalometric radiographs. The ANB angle represents the sagittal skeletal relationship between the maxilla and mandible. A positive change indicates improvement in the sagittal maxillomandibular relationship.

  Baseline to completion of orthopedic treatment (approximately 13 months; treatment continued until achievement of a positive overjet)

Secondary Outcomes (9)

• Change in Sella-Nasion-Point A Angle (SNA)

  Baseline to completion of orthopedic treatment or the corresponding observation period (approximately 13 months)

• Change in Sella-Nasion-Point B Angle (SNB)

  Baseline to completion of orthopedic treatment or the corresponding observation period (approximately 13 months)

• Change in Gonion-Gnathion/Sella-Nasion Angle (GoGn/SN)

  Baseline to completion of orthopedic treatment or the corresponding observation period (approximately 13 months).

• Change in Maxillary Incisor-to-Palatal Plane Angle (U1-PP)

  Baseline to completion of orthopedic treatment or the corresponding observation period (approximately 13 months).

• Change in Incisor Mandibular Plane Angle (IMPA)

  Baseline to completion of orthopedic treatment or the corresponding observation period (approximately 13 months).

Study Arms (2)

Ertty Gap III Group

EXPERIMENTAL

Participants assigned to this arm received orthopedic treatment with the Ertty Gap III appliance. The treatment protocol involved maxillary protraction using an intraoral appliance designed to apply orthopedic forces to the maxillary complex. Treatment was continued until correction of the anterior crossbite and achievement of a positive overjet.

Device: Ertty Gap III Appliance

Facemask Group

ACTIVE COMPARATOR

Participants assigned to this arm received conventional orthopedic maxillary protraction with facemask therapy. Treatment was continued until correction of the anterior crossbite and achievement of a positive overjet.

Device: Facemask Therapy

Interventions

Ertty Gap III Appliance DEVICE

The Ertty Gap III appliance is an intraoral orthopedic appliance designed for maxillary protraction in growing patients with skeletal Class III malocclusion. The maxillary component consists of a sagittally oriented 90° inverted Hyrax expansion screw with an acrylic pad extending from the palatal rugae toward the premaxillary region and posterior occlusal build-ups. The mandibular component consists of a lip bumper-lingual arch assembly supported by the mandibular first permanent molars. Bilateral 5/16-inch, 8-ounce Class III intermaxillary elastics are applied between the maxillary first-molar region and the mandibular lip-bumper notches. The sagittal Hyrax screw is activated once weekly with two consecutive quarter-turns. Patients are instructed to wear the appliance and intermaxillary elastics full time, except during meals, oral hygiene, and contact sports. Patients are monitored at 4-week intervals.

Ertty Gap III Group

Facemask Therapy DEVICE

Conventional maxillary protraction was performed using a Petit-type facemask in combination with a 0.80-mm full-coverage vacuum-formed maxillary splint covering all maxillary teeth. Hooks were incorporated into the splint in the premolar region for attachment of bilateral protraction elastics. Maxillary expansion was not performed in order to isolate the effects of maxillary protraction. Bilateral protraction elastics delivered approximately 350 g of force per side, with the force vector directed approximately 30° downward from the occlusal plane. The applied force was verified using a force gauge at appliance delivery and at each follow-up visit. Participants were instructed to wear the facemask and elastics full time except during meals, oral hygiene, and contact sports. Follow-up visits were scheduled at 4-week intervals to assess appliance integrity, reinforce compliance, verify elastic force levels, and make necessary adjustments.

Facemask Group

Eligibility Criteria

• Age: 9 Years - 12 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Age between 9 and 12 years.
• Late mixed or early permanent dentition.
• Skeletal Class III malocclusion characterized by an A point-Nasion-B point (ANB) angle ≤ 0° and a Class III molar relationship.
• Maxillary deficiency confirmed by clinical and cephalometric assessment, including evaluation of the Sella-Nasion-Point A (SNA) angle according to Steiner analysis (82° ± 2° as the reference) and clinical evidence of perinasal or midfacial deficiency.
• In participants with associated mandibular prognathism, maxillary retrognathia was required to be the predominant skeletal component of the Class III discrepancy.
• Anterior crossbite or an edge-to-edge incisal relationship.
• No previous orthodontic or orthopedic treatment.

You may not qualify if:

• Completed skeletal growth.
• Skeletal Class III malocclusion attributable solely to mandibular prognathism without clinical or cephalometric evidence of maxillary retrognathia.
• Presence of systemic disease.
• Craniofacial syndromes or congenital craniofacial anomalies.
• Temporomandibular joint disorders.
• Congenital absence of maxillary lateral incisors.
• Palatally displaced permanent canines.
• Missing, extracted, or prematurely lost permanent first molars.

Sponsors & Collaborators

• Ankara University: lead

Study Sites (1)

Ankara University, Faculty of Dentistry, Department of Orthodontics

Ankara, Ankara, 06560, Turkey (Türkiye)

Location

Related Publications (2)

• de Souza RA, Rino Neto J, de Paiva JB. Maxillary protraction with rapid maxillary expansion and facemask versus skeletal anchorage with mini-implants in class III patients: a non-randomized clinical trial. Prog Orthod. 2019 Sep 2;20(1):35. doi: 10.1186/s40510-019-0288-7.

  PMID: 31475309 BACKGROUND

• Foersch M, Jacobs C, Wriedt S, Hechtner M, Wehrbein H. Effectiveness of maxillary protraction using facemask with or without maxillary expansion: a systematic review and meta-analysis. Clin Oral Investig. 2015 Jul;19(6):1181-92. doi: 10.1007/s00784-015-1478-4. Epub 2015 May 19.

  PMID: 25982454 BACKGROUND

Study Officials

• Ayse T Altug, DDS, PhD, Professor

  Ankara University, Faculty of Dentistry, Department of Orthodontics

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Because of the nature of the interventions, participants and the treating investigator could not be blinded to treatment allocation. Cephalometric measurements were performed by the treating investigator who delivered the treatments; therefore, the outcome assessor was not blinded. The statistician was blinded to treatment allocation, with the 2 study groups coded as A and B during the statistical analyses.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Assistant

Model Details: Forty-two participants were randomly allocated in a 1:1 ratio to either Ertty Gap III therapy or facemask therapy using a parallel-group design. Participants remained in their assigned treatment group throughout the study.

Study Record Dates

• First Submitted: August 11, 2026
• First Posted: August 18, 2026
• Study Start: May 25, 2024
• Primary Completion: December 9, 2025
• Study Completion: December 9, 2025
• Last Updated: September 15, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)