N-butanol olfactory threshold and nasal patency before and after palatal expansion in children. A preliminary study

Objectives: Olfaction is based on the function of the nasal olfactory receptors. Children can well detect and respond to odors in order to have information about food and environment. Rapid maxillary expansion seems to improve dental class and increase nasal patency correcting oral respiration in children. Nevertheless, there are no studies demonstrating that expansion in pediatric patients could influence olfactory sensitivity. The aim of this study was to evaluate olfactory threshold and nasal patency in children aged from 6 to 12 years before and after rapid maxillary expansion. Method: N-butanol olfactory thresholds, anterior active rhinomanometry, and peak nasal inspiratory flow were measured in 12 children (6-12 years) before (TO), 20 days (T1), and 6 months after rapid maxillary expansion application (T2). Results: A significant lower olfactory threshold was found comparing T2 and TO N-butanol olfactory threshold values (p = 0.038). Peak nasal inspiratory flow showed a significant improvement both at T1 and T2, with respect to TO values (p = 0.043 and p = 0.0001, respectively). T2 nasal resistances showed a trend towards a significant reduction when compared with TI values (p = 0.15). Conclusion: This pilot study suggested that rapid maxillary expansion may lead to improved N-butanol olfactory thresholds, at least 6 months after palatal expansion. Furthermore, rapid maxillary expansion seems to improve peak nasal inspiratory flow values, and finally although with lower sensitivity, reduce nasal resistances as measured by rhinomanometry. (C) 2014 Elsevier Ireland Ltd. All rights reserved.