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NCT Number: NCT07053683

Efficacy of RME and Facemask Therapy for Class III Malocclusion

This multicenter randomized controlled trial compares the efficacy of Rapid Maxillary Expansion (RME) combined with facemask (FM) protraction versus FM protraction alone in treating growing children with skeletal Class III malocclusion. The study aims to evaluate the differences in vertical skeletal changes and Oral Health-Related Quality of Life (OHRQoL) between the two treatments.

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Key information

Conditions

Skeletal Class III Malocclusion Malocclusion Malocclusion, Angle Class III Stomatognathic Diseases Tooth Diseases

Age range

7 year–12 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Wuhan No.1 Hospital

Wuhan, Hubei, 430000, China

About this study

Skeletal Class III malocclusion is a challenging craniofacial anomaly, particularly prevalent in Asian populations. Early orthopedic intervention aims to correct the discrepancy and guide favorable growth. While facemask (FM) protraction is a standard treatment, its efficacy can be enhanced by Rapid Maxillary Expansion (RME), which is thought to disarticulate the circummaxillary sutures and facilitate a better orthopedic response. This prospective, multicenter, randomized controlled trial was designed to rigorously compare the combined RME+FM therapy against FM therapy alone. The study's primary objective was to assess the impact of these interventions on vertical skeletal dimensions, a key concern in Class III treatment. The secondary objective was to evaluate the patient-centered outcome of Oral Health-Related Quality of Life (OHRQoL). Eligible patients aged 7-12 were randomly assigned to one of two treatment groups. Cephalometric and OHRQoL data were collected at baseline and after 12 months of active treatment to determine if the combined approach offers superior clinical outcomes.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Skeletal Class III malocclusion (ANB angle ≤ 0°) with a Wits appraisal ≤ -2 mm.
  • Maxillary deficiency (SNA angle ≤ 80°).
  • Prepubertal stage of skeletal development (Cervical Vertebral Maturation Stage CS1-CS3).
  • Age between 7 and 12 years.
  • Anterior crossbite or edge-to-edge incisor relationship.
  • Angle Class III or end-on molar relationship.
  • No previous orthodontic treatment.

Exclusion criteria

  • Functional Class III malocclusion with no centric relation-centric occlusion discrepancy.
  • Congenital craniofacial anomalies (e.g., cleft lip/palate).
  • Severe systemic diseases.
  • History of maxillofacial trauma.

Treatment and study plan

Combined RME and Facemask Therapy

Device

This intervention involves two components. First, a tooth-borne Hyrax-type rapid maxillary expander is banded to the maxillary first permanent and deciduous molars. The screw is activated twice daily until posterior crossbite is overcorrected. Second, immediately following expansion, a Petit-type facemask is used to apply orthopedic protraction forces to the maxilla.

Facemask Therapy Alone

Device

This intervention involves the use of a Petit-type facemask to apply orthopedic protraction forces (400-500g per side, 12-14 hours/day) to the maxilla. A removable mandibular occlusal splint (flat bite plane) is used concurrently to facilitate anterior crossbite correction.

Primary outcomes

  1. Change in Vertical Linear Cephalometric Measurements

    Time frame: Baseline, 12 Months

    Measured from standardized lateral cephalograms and Cone-Beam Computed Tomography (CBCT) scans. Key measurements include overbite (mm), maxillary molar vertical position (PP-Ms distance, mm), and maxillary anterior position (X-A distance, mm).

  2. Change in Angular Cephalometric Measurements

    Time frame: Baseline, 12 Months

    Measured from standardized lateral cephalograms and CBCT scans. Key measurements include sagittal jaw relationship (ANB angle, degrees), mandibular plane angle (SN-MP, degrees), and palatal plane angle (SN-PP, degrees).

Secondary outcomes

  1. Change in Dental Positional Measurements

    Time frame: Baseline (T0) and 6-month follow-up (T1).

    Change in cephalometric measurements assessing the position and inclination of the incisors, including the UI-NA angle, UI-LI angle (upper to lower incisor angle), UI-NA distance (upper incisor protrusion), and LI-NB distance (lower incisor position). These are measured in degrees or millimeters as appropriate.

  2. Change in Dental Cephalometric Measurements

    Time frame: Baseline, 12 Months

    Measured from lateral cephalograms to assess changes in the inclination of the maxillary and mandibular incisors.

Sponsors and collaborators

Lead sponsor

Wuhan Integrated Traditional Chinese and Western Medicine Hospital

Other

Registry information

Official study title

Enhanced Efficacy of Early Orthopedic Intervention With Rapid Maxillary Expansion and Facemask Protraction on Skeletal and Quality of Life Outcomes in Class III Malocclusion: A Multicenter Randomized Controlled Trial

Important dates

Study start
2019
Primary completion
2023
Study completion
2023
First posted
Jul 8, 2025
Registry last updated
Aug 22, 2025

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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