Pharyngeal Airway Changes After Functional Orthodontic Treatment in Growing Class II Patients: A Retrospective Cephalometric Comparison of Twin Block, RPE and AMCOP®

Pharyngeal airway morphology is closely linked to craniofacial development, and children with Class II malocclusion—often characterized by mandibular retrusion—may present reduced airway dimensions and a higher risk of obstructive sleep apnea. This retrospective single-center study evaluated whether functional orthodontic appliances can improve pharyngeal airway space by promoting mandibular advancement during growth. Fifty patients aged 6–12 years with skeletal Class II malocclusion (ANB > 4◦) were treated with a Twin Block appliance (n = 18), Rapid Palatal Expander (RPE; n = 16), or AMCOP® elastodontic device (n = 16). Pre- and post-treatment lateral cephalograms were analyzed to assess skeletal (SNA, SNB, ANB, Co–Gn), dentoalveolar (overjet, overbite, IMPA), and pharyngeal airway variables (SPAS, MAS, PAS). Intra-group changes were tested with paired t-tests and inter-group differences with one-way ANOVA and Tukey post hoc tests (α = 0.05). All appliances produced statistically significant increases in pharyngeal airway dimensions. The Twin Block group showed the greatest improvements, with mean increases of 2.1 mm in SPAS (p < 0.001), 1.8 mm in MAS (p < 0.001 ), and 1.5 mm in PAS (p < 0.001 ), together with a significant mandibular advancement (∆SNB = +1.7◦; ∆ANB = −1.5◦) and elongation of mandibular length (∆Co–Gn = +3.3 mm). RPE and AMCOP® induced more moderate, yet significant, skeletal and airway changes (RPE: SPAS +1.4 mm, p = 0.006 ; MAS +0.9 mm, p = 0.009; PAS +0.8 mm, p = 0.022; AMCOP®: SPAS +0.9 mm, p = 0.034; MAS +0.9 mm, p = 0.041; PAS +0.6 mm, p = 0.037). Within the limitations of this small, retrospective single-center sample, the findings indicate that functional orthodontic treatment during growth may be associated with increases in pharyngeal airway dimensions in Class II patients. Among the appliances evaluated, the Twin Block showed the most pronounced skeletal and morphological airway changes.