Olfactory Threshold Changes Following Rapid Maxillary Expansion in Adolescents: A Prospective Sniffin’ Sticks (PEA) Study

Abstract

Background: This study aims to evaluate the effects of rapid maxillary expansion (RME) treatment on olfactory threshold.

Methods: The study included 31 adolescents (18 females, 13 males; 12.7 ± 0.7 years) undergoing RME. Olfactory threshold was evaluated at 3 time points—before RME (T0), immediately after completion of the activation protocol (T1), and 6 months post treatment (T2)—using the Sniffin’ Sticks Threshold Test with phenylethyl alcohol (Burghart, Wedel, Germany). The mean of the last 4 reversal points was recorded as the threshold score. Data were analyzed using Friedman’s test due to non-normal distribution (Shapiro–Wilk, P < .05).

Results: Mean olfactory threshold values showed minimal variation across time points (T0: 8.46 ± 1.48; T1: 8.58 ± 1.34; T2: 8.48 ± 1.39), with no significant overall difference (Friedman test, P=.122). Sex-based comparisons also revealed no significant differences at any time point (T0: P=.488; T1: P=.424; T2: P > .05).

Conclusion: Rapid maxillary expansion treatment did not result in statistically significant changes in olfactory threshold scores. Additionally, no significant differences were observed between genders in terms of olfactory function.

Cite this article as: Çifçi-Özkan E, Gürel HG, Ağaoğluu-Mogul E. Olfactory threshold changes following rapid maxillary expansion in adolescents: A prospective sniffin’ sticks (PEA) study. Essent Dent. 2026, 5, 0069, doi:10.5152/EssentDent.2026.25069.