Assesment of the effects of rapid maxillary expansion on olfactory function

The aim of our study was to evaluate the effect of rapid maxillary expansion (RME) treatment on nasal airway with anterior rhinomanometry (ARM) and Nasal Obstruction Symptom Evaluation Scale (NOSE) and on olfactory function with "Sniffin" Sticks test. Our study consisted 48 patients aged between 12 and 16 years who applied to our clinic for orthodontic treatment. Group B comprised 17 patients that required RME treatment and who were nasal breathers, while group A consisted of 16 patients who also required RME but who were both nasal and oral breathers. 15 patients who did not have transverse maxillary deficiency and who were nasal breathers were included in the control (K) group. In the treatment groups, tooth-tissue-borne full coverage acrylic bonded rapid maxillary expander was used for RME. ARM, NOSE and Sniffin Sticks measurements were performed before RME treatment (T0), at the end of active treatment (T1) and at the end of treatment (T2). The measurements were also performed simultaneously in the control group. Repeated measures ANOVA and Friedman analysis with Post-hoc Holm-Sidak and Bonferroni-corrected Wilcoxon tests were used for the intra-group comparisons while One-way ANOVA and Post-hoc Tukey tests were used for inter-group comparison. No significant difference was observed in the ARM, NOSE and Sniffin Sticks measurements of the control group between T0, T1 and T2 (p> 0.05). Significant decreases in nasal resistances were recorded after treatment in groups A and B, in terms of ARM and NOSE measurements (p<0.001). In treatment groups, "Sniffin" Sticks " values increased significantly and olfactory function was observed (p <0.001). When ARM measurements were compared between groups, the changes in group A and B were significantly higher than group K (p <0.05). When olfactory function was compared, between groups the increases in group A and B were significantly higher than group K in T2-T1 and T2-T0. As a result of our study, improvement in nasal airway has been achieved with RME treatment. Relief of nasal respiration decreased the symptoms of nasal obstruction and increased quality of life. The amount of air reaching the olfactory region and carried odor molecules increased with the alleviation of nasal congestion. An improvement in the olfactory function was observed with the decrease in the transport-type olfactory disorder.