Aim: To evaluate the effects of rapid maxillary expansion (RME) on nasal patency in mouth breathing (MB) children with maxillary atresia due to or not due to allergic rhinitis (AR) associated with asthma.
Methods: Fifty-three MB children/adolescents (aged 7–14 years) with mixed or permanent dentition and maxillary atresia participated, with or without unilateral or bilateral crossbite. They formed the groups: RAD (AR + asthma; clinical treatment, RME); RAC (AR + asthma; clinical treatment, no RME); and D (mouth breathers; RME only). RAD and RAC patients received topical nasal corticosteroid and/or systemic H1 antihistamine (continuous use) and environmental exposure control. All were evaluated before RME (T1) and 6 months after (T2) with the CARATkids score, acoustic rhinometry, and nasal cavity computed tomography (CT). Patients RAD and D underwent RME (Hyrax® orthopedic appliance).
Results: A significant reduction in the CARATkids score occurred in the RAD (−4.06; p < 0.05), similarly when patient and parent/guardian scores were evaluated (−3.28 and −3.16, respectively). Acoustic rhinometry (V5) showed increased nasal volume in all groups, significantly higher in RAD patients than in RAC and D (0.99 × 0.71 × 0.69 cm3, respectively). CT of the nasal cavity documented increased volume in all three groups, with no significant differences between them.
Conclusion: In MB patients with AR, asthma, and maxillary atresia, RME increased nasal cavity volume and improved respiratory symptoms. However, it should not be used as the only treatment for managing patients with respiratory allergies.