Abstract
Obstructive sleep apnea (OSA) is a prevalent disorder characterized by repeated upper airway collapse during sleep, significantly impacting quality of life. Orthodontists are increasingly recognized for their role in screening and managing anatomical factors contributing to airway obstruction. One such intervention is rapid maxillary expansion (RME), originally developed to address transverse maxillary deficiencies but now also studied for its influence on nasal and oropharyngeal airway dimensions. This literature review evaluates the effects of maxillary palatal expansion on airway volume and respiratory function. Evidence consistently shows increases in nasal cavity volume and reductions in nasal airway resistance, particularly in patients treated before the peak of skeletal growth. Some studies reported improvements in sleep outcomes and enhanced oxygen saturation following MARPE in adults with OSA. Results regarding changes in oropharyngeal volume were more variable, with several studies showing significant expansion. Factors influencing outcomes include patient age, skeletal maturity, appliance type, and aging modality. Hybrid and bone-borne expanders generally demonstrated greater skeletal effects compared to tooth-borne devices, though statistical significance was not always reached. While MARPE has shown promising results in non-obese adults with OSA, long-term stability of airway improvements and translation into consistent functional respiratory benefits remain uncertain. Overall, maxillary expansion demonstrates measurable skeletal and airway changes, with the greatest respiratory improvements in growing patients and selected adult populations. Incorporating patient-reported outcomes and standardized polysomnographic measures in future trials will be critical to determine whether these structural gains consistently translate into durable improvements in sleep-disordered breathing and quality of life.