Effect of rapid maxillary expansion on nasal cavity assessed with cone-beam computed tomography.

INTRODUCTION: Rapid maxillary expansion (RME) is assumed as a well established procedure; although, some effects on facial complex are not yet fully understood. OBJECTIVE: The aim of this research was to verify, using cone-beam computed tomography, the effect on linear dimensions of the nasal cavity. METHODS: Sample consisted of twenty patients aged 7 to 16 years, with skeletal deformity that justified the use of CT scans, and who required the RME as part of the orthodontic treatment planning. Scans were taken before clinical procedures were performed (T0) and after stabilizing the expander screw (T1). Dolphin Imaging v. 11.5 3D software was used to measure six areas on nasal cavity: three at the anterior portion (upper, middle, and lower) and other three at the posterior portion (also upper, middle, and lower). Data were statistically treated using Shapiro-Wilk test to verify normality. Differences between T0 and T1 were calculated using the Spearman correlation and paired Student's t-test, with a significance level of 5%. RESULTS: All linear measurements presented a significant increase (p< 0.05) after RME, both in the anterior and posterior regions, suggesting some parallelism on the opening pattern, especially at the lower portion (p< 0.001). CONCLUSIONS: RME was able to significantly modify the internal dimensions of the nasal cavity.