Influence of nasal septum deviation on fluctuating asymmetries of the nasomaxillary complex: A cross-sectional study

An important parameter in diagnostic analysis and treatment planning of different biological areas is facial symmetry, and several etiological factors have been attributed to skeletal facial asymmetry. Although causality cannot be determined, previous studies have reported a relationship between the anatomical deviation of the nasal septum and facial development. Diagnosis is critical for patients in growth stages due to the association between nasal septum deviation (NSD) and abnormal growth of the nasomaxillary complex. To understand this relationship, this study aimed to investigate the influence of nasal septum deviation on fluctuating asymmetries (FA) of the nasomaxillary complex at different stages of skeletal maturation. Another goal was to determine whether an association exists between the degrees of septal deviation severity and asymmetry of the nasomaxillary complex. This was a retrospective, cross-sectional observational study comprising 60 selected cone-beam computed tomography (CBCT) scans that were divided into four groups (n = 15) according to the degree of septal deviation and skeletal maturation: mild deviation (MD; <10°), moderate to severe deviation (MSD; ≥10°), early group (EG), and late group (LG). The angle and area of deviation were measured for the greatest NSD, and a geometric morphometric approach was used to evaluate the nasal septum (NS) shape. The morphology of the nasomaxillary complex and the presence of fluctuating asymmetries were evaluated using 23 two-dimensional landmarks on the nasomaxillary complex (nasal, lateral, and palatal regions) with Procrustes ANOVA and Mann-Whitney test. Additionally, Spearman's correlation and multivariate regression were used to correlate the NSD with asymmetries in these regions. No significant differences were observed in the Procrustes FA scores of the nasomaxillary complex between the MD-EG × MSD-EG and MD-LG × MSD-LG (p > 0.05). However, the results of the multivariate regression revealed more specific aspects of asymmetry (asymmetry component), there was a positive correlation between the NSD angle and the palatal regions (p = 0.035 and p = 0.047, middle and posterior, respectively), and the nasal septum shape and anterior palatal regions (p = 0.039). The nasal and lateral regions did not correlate with the NSD angle in the multivariate regression analysis (p > 0.05). The results of this study indicate that there were no significant differences in the fluctuating asymmetry of the nasomaxillary complex between the mild and moderate to severe nasal septum deviation groups, in both early and late skeletal maturation stages. However, a positive correlation was observed in the degree of nasal septum deviation angle and asymmetry components of the middle and posterior palatal regions, likewise between the nasal septum shape and asymmetry components of the anterior palatal region. The diagnosis of nasal septum deviation by both physicians and dentists is important, as a relationship was observed with fluctuating asymmetry component of the palatal region. This information can guide the decision of the treatment planning for these individuals, and should be considered, especially in cases of severe septum deviation, due to the great anatomical proximity of these structures.