Assessment of the Effect of Rapid Maxillary Expansion on Nasal Respiratory Function and Obstructive Sleep Apnea Syndrome in Children: A Systematic Review.

: Obstructive sleep apnea syndrome (OSAS) and impaired nasal breathing are common in children and are frequently linked to maxillary constriction. Rapid maxillary expansion (RME) is an orthopedic treatment used to increase upper airway dimensions and improve respiratory function. It has been hypothesized that RME could contribute to improvements in behavior and cognition, possibly through enhanced sleep and respiratory function. It also promotes the shift from oral to nasal breathing, supporting craniofacial development and neuromuscular stability, and it is increasingly recognized as a multidisciplinary intervention that can improve pediatric health outcomes. With increasing evidence supporting its efficacy, RME should be considered not only for its orthodontic benefits but also as a multidisciplinary treatment option within pediatric care protocols. This underscores the importance of integrated care among orthodontists, ENT specialists, and pediatricians. To systematically assess the impact of RME on nasal respiratory parameters and sleep-disordered breathing, particularly OSAS, in pediatric patients. Following PRISMA guidelines, a systematic review was conducted using 12 clinical studies evaluating anatomical and functional respiratory changes after RME in children with mouth breathing or OSAS. Parameters included airway volume (CBCT, cephalometry), nasal resistance (rhinomanometry), and polysomnography (PSG) data. RME consistently resulted in significant increases in nasal cavity volume and upper airway dimensions. Multiple studies reported reductions in the apnea-hypopnea index (AHI), improved oxygen saturation, and better subjective sleep quality. Longitudinal studies confirmed the stability of these benefits. However, variability in study protocols limited meta-analytical comparison. RME is effective in enhancing nasal breathing and mitigating OSAS symptoms in children. While results are promising, further high-quality randomized controlled trials are needed to validate these findings and guide standardized treatment protocols.