Evaluation of nasal capacity before and after rapid maxillary expansion

BACKGROUND: This study analyzed the effects of orthodontic maxillary expansion on the nasal cavity dimensions measured by acoustic rhinometry. METHODS: A prospective study was performed. Fifty patients (27 male and 23 female patients) who had maxillary hypoplasia in relation to the mandible were studied. Patients presented either deciduous or mixed dentition, with age ranging from 4 to 14 years old. Twenty patients (11 male and 9 female patients) between the ages of 4 and 11 years, who also had deciduous or mixed dentition but without maxillary hypoplasia, served as a control group. A modified Biederman appliance was used for approximately 20 days to achieve the maxillary expansion in the treatment group. Acoustic rhinometry, with measurements of the right and the left nasal cavity, was performed before starting the maxillary expansion (T1) and at its conclusion (T2). This procedure was conducted also at a comparable time interval in the control group. RESULTS: The treated group showed a significant increase in the majority of the values of transversal areas and nasal volumes when compared with the nontreated group. CONCLUSION: In children with maxillary hypoplasia, rapid maxillary expansion can not only move the maxilla and alveolar arches laterally but it can also increase the size of the nasal cavities.