Efficacy of van Beek headgear activator in adolescents with UARS and hyperdivergent skeletal class II malocclusion: dentofacial morphology, airway, and growth

BACKGROUND: This study aimed to evaluate the comprehensive efficacy of van Beek Headgear Activator (VB) in treating adolescent Upper Airway Resistance Syndrome (UARS) patients with mouth breathing-induced high-angle skeletal Class II malocclusion. METHODS: Patients were divided into a VB group and a control group. Lateral cephalometric radiographs taken at baseline (T0) and post-treatment (T1) were analyzed for craniofacial changes. Upper airway morphology and function were evaluated using the lateral cephalometric adenoid-to-nasopharyngeal length ratio (A/N), polysomnography results (PSG), and OSA-18 scores. Cone-beam computed tomography was used to assess transverse discrepancies (T-W: maxillary width - mandibular width - 5 mm). And the distribution of height and weight percentiles was compared between the two groups. RESULTS: A total of 48 subjects were enrolled in this study, with 30 in the VB group and 18 in the control group. In the VB group, SNA (mean decrease: 1.62°) and FH-NA (median decrease: 1.55°) showed significant pre-post reductions, and these changes were significantly different from those in the control group (all p < 0.001). Additionally, mandibular growth was moderately stimulated in the VB group, with Co-Go length showing a statistically significant median increase of 3.70 mm (p < 0.001). VB appliance therapy significantly improved transverse discrepancy, with a mean increase of 4.47 mm in the T-W value (p < 0.001). Over the observation period, both groups showed highly significant improvements in all airway outcomes and quality-of-life outcomes (A/N, AHI, minimum SpO₂, and OSA-18 scores; all p ≤ 0.01), with significantly greater improvements in the VB group across all parameters (all p < 0.001). A significant increase in height and weight percentiles was observed in the VB group (p < 0.001), whereas no changes were observed in the control group. CONCLUSIONS: In a subset of children with conditional UARS who do not meet typical surgical indications, after the use of the VB functional appliance, improvements in sagittal jaw relationship and increases in transverse maxillary width were observed. Compared with the control group, the VB group showed certain improvements in airway-related parameters, sleep respiratory indices, and growth and development metrics, thereby providing preliminary evidence supporting non‑surgical intervention for this condition.