Long-Term Outcomes of Class III Malocclusion Interception With Maxillary Expansion and Protraction: A 9-Year...

This case report presents the successful long-term management of a Class III malocclusion in an 8-year-old male patient treated with maxillary protraction facemask therapy (MPFM) combined with Hyrax-type maxillary expansion (HME), followed by a 9-year follow-up period. The patient presented with a Class III malocclusion (Angle classification), anterior and posterior crossbite, maxillary hypoplasia, and compromised facial esthetics. The treatment protocol consisted of 12 months of MPFM with HME, followed by retention using a modified Type III activator and chin cup, and subsequent fixed orthodontic therapy for final occlusal refinement. Cephalometric evaluation demonstrated significant skeletal improvements, with the ANB angle increasing from -1.0° to 3.1°, the SNA angle increasing from 82.0° to 84.2°, and the SNB angle decreasing from 83.0° to 81.1°. A marked increase in maxillary incisor inclination was observed, with the U1-NA angle increasing from 24.5° to 33.8°. Mandibular incisors exhibited minor linear positional changes (L1-NB, millimeters) and a reduction in angular inclination (L1.NB), indicating dentoalveolar adaptation during treatment. The overjet correction was particularly notable, improving from -1.7 to 3.4 mm, whereas enhanced lip support contributed to improved facial esthetics. The 9-year follow-up examination revealed excellent stability in maxillomandibular relationships, with maintained molar and incisor positions as well as stable overjet and overbite measurements. This case demonstrates that early intervention combining HME and MPFM can effectively correct Class III malocclusion with maxillary hypoplasia and mandibular prognathism. However, the importance of continued growth monitoring following active treatment cannot be overstated, as residual growth patterns may influence long-term stability. These findings support the use of interceptive orthopedic approaches in growing Class III patients while emphasizing the need for extended follow-up through the remaining growth period. This stability is interpreted considering growth-related drift: the postpubertal reduction in ANB and overjet reflects residual mandibular growth rather than relapse, whereas stable incisor proclination contributed to occlusal maintenance.