Interception of Class III malocclusion with facemask therapy: A retrospective cohort study

Abstract

Background: Class III malocclusion, characterized by maxillary retrusion or mandibular prognathism, poses significant challenges in orthodontic treatment. Early intervention with facemask therapy aims to correct skeletal discrepancies, but outcomes vary. This study evaluates the efficacy of rapid palatal expansion (RPE) and facemask therapy in improving maxillomandibular relationships in growing children with Class III malocclusion. Material and Methods: A retrospective cohort study was conducted on 37 patients (mean age 7.5 ± 1.1 years) treated with RPE and Petit facemask therapy. Cephalometric radiographs were analyzed at treatment onset (T0) and completion (T1). Patients were divided into Group 1 (favorable outcome, ANB angle increase) and Group 2 (unfavorable outcome, ANB unchanged/decreased). Statistical analysis included dependent and independent t-tests to compare skeletal and dental changes. Results: Group 1 (62.2% of patients) showed significant improvements in ANB angle (1.85° increase), maxillary position (SNA, A-Nperp), and cranial base dimensions (S-N, S-Ar). Group 2 (37.8%) exhibited worsening maxillomandibular relationships (ANB decrease of 1.0°). Key differences included cranial base angle (NSAr), maxillary sagittal position, and mandibular prognathism (Pog-Nperp). Vertical growth increased in both groups, with no significant rotational changes in the mandible or maxilla. Conclusions: Facemask therapy with RPE effectively improved skeletal Class III malocclusion in 62.2% of cases, primarily through maxillary advancement and cranial base adaptation. Unfavorable outcomes were associated with larger initial ANB angles and mandibular prognathism. Early intervention during prepubertal growth stages is recommended for optimal results. <b>Key words:</b>Class III malocclusion, Orthopedic fixation devices, Maxillary expansion, Cephalometry, Retrospective studies.