Skeletal Class III Malocclusion
Conditions
Keywords
Palatal Expansion Technique, Extraoral Traction Appliances, Malocclusion, Angle Class III, Cephalometry, Rapid Maxillary Expansion, Oral Health-Related Quality of Life
Brief summary
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.
Detailed description
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.
Interventions
DEVICECombined RME and Facemask Therapy
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.
DEVICEFacemask Therapy Alone
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.
Sponsors
Wuhan Integrated Traditional Chinese and Western Medicine Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
7 Years to 12 Years
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Vertical Linear Cephalometric Measurements | 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). |
| Change in Angular Cephalometric Measurements | 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
| Measure | Time frame | Description |
|---|---|---|
| Change in Dental Positional Measurements | 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. |
| Change in Dental Cephalometric Measurements | Baseline, 12 Months | Measured from lateral cephalograms to assess changes in the inclination of the maxillary and mandibular incisors. |
Countries
China
Outcome results
None listed