Changes in the Upper Airway Dimension Following the Use of Functional Appliances in Children with Obstructive Sleep Apnea: A Systematic Review

Introduction: Obstructive Sleep Apnea Syndrome (OSAS) is a sleep-related breathing disorder common in children, often linked to craniofacial anomalies like retrognathic mandibles in Class II malocclusions. Functional appliances (FAs) have been proposed as non-invasive treatments to improve OSAS symptoms by modifying upper airway dimensions. Objective: this systematic review evaluates the effectiveness of functional appliances in improving upper airway structures in children with OSAS. Materials and Methods: the study was conducted according to PRISMA guidelines, analyzing studies published between 2004 and 2024 on PubMed, Scopus, Web of Science, Embase, and Cochrane Library databases. Inclusion criteria focused on growing patients (≤14 years) with OSAS and Class II skeletal malocclusions treated with FAs. Results: Of 1298 articles screened, four studies met the inclusion criteria. All studies reported a significant increase in upper airway dimensions of approximately 21% after treatment with FAs. Specifically, the cephalometric and tomographic evaluations revealed a clear enlargement of the superior posterior airway space of about 0.5 mm and a consequent improvement of the respiratory function. Discrepancies arose regarding changes in soft palate length and hyoid bone position, perhaps due to the measurement methods’ variation. Conclusions: Functional appliances appear effective in improving upper airway dimensions and alleviating OSAS symptoms in children. However, the limited number of studies, small sample sizes, and short follow-up periods emphasize the need for further research to confirm long-term efficacy and standardize evaluation protocols.