Effects of symmetric and asymmetric rapid maxillary expansion treatments on pharyngeal airway and sinus volume: A cone-beam computed tomography study

Objective: To evaluate pharyngeal airway and maxillary sinus volumes following symmetric rapid maxillary expansion (RME) and asymmetric rapid maxillary expansion (ARME) treatment using cone-beam computed tomography (CBCT). Materials and Methods: The study consisted of 60 patients presenting to the orthodontics clinic with an indication that they required symmetric or asymmetric rapid maxillary expansion treatment. Individuals were included if they were aged 12-15 years and had symmetric (RME group; 14 girls, 16 boys) or asymmetric (ARME group; 16 girls, 14 boys) maxillary deficiency. Maxillary sinus volume (mm(3)) and pharyngeal airway volume (upper, lower, and total; mm(3)) were evaluated using CBCT records. The parameters were compared before treatment (T1) and after 3 months in retention (T2). Results: All measurements at T2 were increased significantly compared with T1 in the RME group (P < .05). In the ARME group, changes in the lower pharyngeal airway and the nonaffected maxillary sinus volumes (non-affected side of maxillary sinus volumes) were not significant; however, the other measurements increased significantly from T1 to T2 (P < .05). Intergroup comparisons revealed that total pharyngeal airway volume and total maxillary sinus volume changes were significantly greater in the RME group. Conclusions: Pharyngeal airway and maxillary sinus volumes increased with both RME and ARME treatment. Both were found to be effective for treating transverse maxillary deficiency.