Association between nasal cavity anatomical variations and palatal dimensions in pediatric patients: a CBCT study

Abstract

Background

This retrospective cross-sectional study aimed to evaluate the associations of nasal septum deviation (NSD), concha bullosa (CB), and inferior turbinate hypertrophy (ITH) with palatal dimensions using cone-beam computed tomography (CBCT).

Methods

CBCT images of patients younger than 18 years obtained between January 2021 and May 2025 were retrospectively evaluated. A total of 108 eligible subjects were included and categorized into four groups based on the presence of NSD and CB. Maxillary palatal arch angle (MPAA), palatal interalveolar length (PIL), and palatal depth (PAD) were measured. Group comparisons were performed using age-adjusted ANCOVA, and associations between palatal measurements, deviated septal curve angle (DSCA), and age were analyzed using correlation and regression analyses.

Results

Unadjusted analyses revealed significant age differences among the groups. After age adjustment, no significant differences were observed in MPAA, PIL, or PAD (p > 0.05). A weak positive correlation was found between DSCA and MPAA (r = 0.219; p = 0.023), whereas no significant correlations were detected for PIL or PAD. Regression analysis showed that age was the only significant predictor of palatal measurements.

Conclusion

Age was the only significant predictor of palatal measurements in this pediatric sample. Within the CBCT-based anatomical variables evaluated, NSD, CB, and ITH were not independently associated with palatal dimensions after adjustment for age. These findings should not be generalized to functional nasal obstruction or respiratory patterns, which were not assessed in this study.

Introduction

Nasal breathing is the primary physiological pathway for air intake, and its role in craniofacial development has received increasing attention in recent years. According to functional matrix theory, the vertical movement of the palate and lateral expansion of the maxilla are stimulated by the continuous airflow passing through the nasal cavities, indicating a close relationship between nasal breathing and dentofacial anatomy [1]. However, due to obstructive pathologies or habits, mouth breathing may replace nasal breathing, adversely affecting dentofacial structures [2, 3]. These alterations may result in moderate to severe maxillary narrowing, posterior crossbite, increased overjet, and increased palatal depth are changes observed in the oral cavity. Extraorally, an adenoid face, convex facial profile, and increased lower height may develop [4]. Among the anatomical factors associated with mouth breathing, hypertrophic adenoids, maxillary sinusitis, concha bullosa (CB), nasal septal deviation (NSD), and inferior turbinate hypertrophy (ITH) have been reported as common causes of nasal obstruction [5].

In the developmental process, the nasal septum functions like a growth plate, playing an important role in adjacent bones and facial skeletal structures [6]. It also maintains the structural integrity of the nasal cavity, dividing it into two parts and regulating airflow [7]. Due to its central location, the nasal septum is exposed to stress from maxillopalatine structures. Mechanical forces transmitted from the maxillopalatine structures may predispose the nasal septum to deviation [8]. NSD is reported to have an incidence of up to 80–90%, can be congenital or acquired, and may affect facial skeletal development [9]. The inferior, middle, and superior turbinates located on the lateral wall of the nasal cavity are significant components of the sinonasal structure. Among these structures, concha pneumatization, in particular, has been described in the literature as an anatomical variation associated with NSD [10]. An increase in the deviation angle of the NSD may increase the pneumatization of the middle concha [11].

Accurate radiological evaluation of these anatomical variations is important for understanding their potential relationship with dentofacial morphology and for supporting individualized diagnosis and treatment planning. Although panoramic and lateral cephalometric radiographs are generally sufficient for early orthodontic assessment, Cone beam computed tomography (CBCT) may be indicated for the evaluation of jaw developmental anomalies, cleft palate, the upper airway, and the temporomandibular joint [12].

This retrospective study investigates the associations of anatomical variations and related conditions of the nasal cavity, such as NSD, CB, and ITH with palatal depth and length using CBCT. The null hypothesis was that these nasal cavity features (NSD, CB, and ITH) would have no significant association with palatal dimensions (MPAA, PIL, and PAD).

Materials and methods

Ethical approval

The study protocol of this retrospective observational study was reviewed and approved by the Clinical Research Ethics Committee of *** University, Faculty of Medicine (Approval No: XXX). All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008. The requirement for informed consent was waived due to the retrospective nature of the study.

Sample size calculation

Based on a one-way fixed-effects ANOVA and the parameters reported by Shetty et al. [13], the required sample size was estimated as 108 subjects using G*Power software (version 3.1.9.7), with α = 0.05, statistical power = 95%, and an effect size of 0.385.

CBCT image acquisition

The CBCT examinations were performed using a Kavo OP 3D Vision system (Imaging Sciences International LLC, USA). Imaging conditions included 90–120 kVp, 3–8 mA, and exposure times of 4.8–26.9 s. The field of view (FOV) dimensions ranged from 6 × 16 cm to 17 × 23 cm, and voxel resolution was between 200 and 600 μm.

Study design and patient selection

This retrospective cross-sectional observational study was conducted using CBCT images of patients aged 18 years and younger who applied for various dental treatments at the Faculty of Dentistry of *** University between January 2021 and May 2025. A total of 659 CBCT scans were retrospectively screened. CBCT scans in which the nasal septum and maxilla were completely included within the field of view were eligible for evaluation. After applying the inclusion and exclusion criteria, 108 subjects aged between 6 and 18 years were included in the final analysis. The age range of 6–18 years was deliberately selected to include pediatric and adolescent subjects during the active period of craniofacial and maxillary development. The patient selection process is illustrated in Fig. 1.

Fig. 1.

Flowchart illustrating patient selection and study inclusion process

Images with motion or metal artifacts and unsatisfactory quality were excluded from the study (n = 11). Patients with bone lesions (n = 12), fractures (n = 5), cleft palate (n = 3), orthodontic treatment or orthognathic surgery (n = 17), and adenoid hypertrophy (n = 2) were also excluded from the study.

Image interpretation

The CBCT data were analyzed with OnDemand3D software (CyberMed, Seoul, Republic of Korea) on 27-inch Dell Precision T3620 medical monitors (Dell, Round Rock, TX, USA) featuring a resolution of 1920 × 1200 pixels and 64-bit color. Coronal and sagittal sections were generated with an interslice distance of 0.175 mm.

Based on the presence or absence of NSD and CB, the patients were categorized into four groups.

• Group 1: NSD and CB absent

• Group 2: NSD present

• Group 3: CB present

• Group 4: NSD and CB present

CB was defined as the presence of an air-filled pneumatized cavity within the middle nasal concha, surrounded by thin bony walls on coronal CBCT sections. ITH was defined as enlargement of the inferior nasal concha on coronal sections, characterized by increased bony and/or mucosal thickness with narrowing of the corresponding inferior nasal airway. CB and ITH were recorded as absent, unilateral, or bilateral (Fig. 2). These assessments were performed qualitatively on CBCT images without further severity grading.

Fig. 2.

The asterisk represents inferior turbinate hypertrophy, and the arrow shows concha bullosa

After CB and ITH assessment, deviated septal curve angle (DSCA), deviated septal length (DSL), maxillary palatal arch angle (MPAA), palatal interalveolar length (PIL), and palatal arch depth (PAD) were measured as detailed below:

DSCA was measured between the following three points in the coronal section.

1. The point where the nasal septum intersects the floor of the nasal cavity.

2. Crista galli.

3. The outermost part on the convexity of the deviated septum.

The septum was defined as deviated when DSCA was less than 150°, as reported by Akbay et al. [14] (Fig. 3a). This method was preferred because it provides a standardized, reproducible, and objective angular assessment of nasal septum deviation on CBCT images and has been previously validated in the literature.

Fig. 3.

Anatomical landmarks and measurements used in the study. (a) DSCA, deviated septal curve angle; (b) DSL, deviated septal length; (c) MPAA, maxillary palatal arch angle; (d) PIL, palatal interalveolar length; and (e) PAD, palatal arch depth. Point P represents the intersection of the vertical reference line extending from the crista galli with the palate. The anatomical landmarks used for MPAA, PIL, and PAD measurements are indicated in the figure

DSL was defined as the horizontal distance from the apex of septal deviation to the perpendicular reference axis (Fig. 3b).

In the coronal sections, the point where the vertical reference line extending inferiorly from the crista galli intersected the palate was defined as Point P. The right and left alveolar midpoints were identified at the level of the maxillary first molars. MPAA was calculated as the angle formed by the lines connecting Point P to the bilateral alveolar midpoints (Fig. 3c). PIL was measured as the linear distance between the bilateral alveolar midpoints (Fig. 3d). PAD was defined as the perpendicular distance from Point P to the interalveolar line connecting the bilateral alveolar midpoints (Fig. 3e) [14].

All measurements were performed by an experienced dentomaxillofacial radiologist (M.Ç.) with nine years of experience. To minimize measurement bias, standardized anatomical landmarks based on validated methodologies were used. The examiner was not blinded during image evaluation because the assessments were performed retrospectively using archived CBCT images. To assess intraobserver reliability, the examiner re-evaluated a subset of 27 CBCT scans (representing 25% of the total sample) after a three-week interval.

Statistical analysis

All statistical procedures were carried out in SPSS (version 27; SPSS Inc., Chicago, IL). Agreement within the observer was quantified through Cohen’s kappa coefficient for categorical data and intraclass correlation coefficients for continuous data. In addition, the Dahlberg error was calculated for all continuous measurements to quantify the magnitude of random measurement error using the formula √(Σd²/2n), where d represents the difference between repeated measurements and n represents the number of repeated measurements. The normality of the data was assessed using the Shapiro–Wilk test. The distributions of CBCT acquisition parameters, including FOV and voxel size, were compared among the study groups using the chi-square test. The differences between genders in the measurements were analyzed by independent sample t-test. Group comparisons of MPAA, PIL, and PAD were performed using analysis of covariance (ANCOVA). Since age differed significantly among the study groups, age was included as a covariate to control for its potential confounding effect. Before interpreting the ANCOVA models, the homogeneity of regression slopes assumption was evaluated by testing the interaction between age and study group for each dependent variable. Effect sizes were reported as partial eta squared, and age-adjusted estimated marginal means with 95% confidence intervals were calculated. One-way ANOVA was used to analyse the differences between the MPAA, PIL and PAD values in the ITH and CB subtypes. Correlation of hard palate measurements with DSCA and age was assessed using Pearson correlation test. The association between DSL and hard palate measurements was evaluated using Spearman correlation analysis in patients with nasal septum deviation. DSCA was analyzed as a continuous variable in both the correlation and multiple linear regression analyses. Multiple linear regressions were performed to analyze the predictive value of age, gender, DSCA, ITH and CB on MPAA, PIL and PAD values. Before interpreting the regression models, the assumptions of multiple linear regression were evaluated. Residual normality was assessed using histograms and normal probability (P–P) plots, homoscedasticity was evaluated by visual inspection of standardized residual versus standardized predicted value plots, multicollinearity was assessed using tolerance and variance inflation factor (VIF) values, and independence of residuals was evaluated using the Durbin–Watson statistic. Statistical significance was set at p < 0.05.

Results

Intra-observer agreement was excellent for all continuous measurements (ICC range: 0.908–0.997, p < 0.001) [15]. The corresponding Dahlberg errors were 1.08° for DSCA, 0.44 mm for DSL, 1.33° for MPAA, 0.64 mm for PIL, and 0.59 mm for PAD, indicating low random measurement error. For qualitative assessments, Cohen’s kappa values indicated almost perfect intra-observer agreement for NSD (κ = 1.000), right CB (κ = 0.931), left CB (κ = 0.882), right ITH (κ = 0.852), and left ITH (κ = 1.000) (p < 0.001) [16].

In total, 108 consecutively evaluated subjects between the ages of 6 and 18 years (mean, 13 ± 3.3 years) were assessed. No statistically significant difference was observed in gender distribution among the groups. Groups 1–3 comprised 14 females and 13 males, and group 4 comprised 15 females and 12 males. The mean ages were 13.4 ± 2.9 years for females and 12.6 ± 3.8 years for males, showing no significant difference (p = 0.293). Group 4 exhibited a significantly greater mean age than the other groups, with overall age differences reaching statistical significance (Table 1). The distribution of CBCT acquisition parameters was also evaluated among the study groups. Voxel size distribution did not differ significantly between the groups (χ² test, p = 0.075), whereas FOV distribution showed a significant difference (χ² test, p = 0.001).

Table 1.

The comparison of the mean age of the four groups

	Group 1	Group 2	Group 3	Group 4	F	p*
Age	12.3 ± 3.2a	12.6 ± 3.5a	12 ± 3.1a	15.1 ± 2.9b	5.449	0.002

*ANOVA, a-b: No difference between groups with the same letter for each row

MPAA values ranged from 104.6 ± 12.1 in group 4 to 110.0 ± 11.0 in group 3 (Table 2). Mean PAD values were highest in group 4 (13.1 ± 2.4) (Table 2). Unadjusted comparisons revealed significant differences in age among the study groups (p < 0.05). Therefore, ANCOVA was performed to adjust for the potential confounding effect of age. Before interpreting the ANCOVA models, the assumption of homogeneity of regression slopes was evaluated by testing the age × group interaction for each dependent variable. No significant age × group interaction was observed for MPAA, PIL, or PAD (p > 0.05), indicating that this assumption was satisfied. After adjustment for age, no statistically significant differences were found among the study groups with respect to MPAA, PIL, or PAD (p > 0.05; Table 3). Age-adjusted estimated marginal means and their corresponding 95% confidence intervals are presented in Table 4. The 95% confidence intervals of the age-adjusted estimated marginal means overlapped among the study groups for all palatal measurements.

Table 2.

Descriptive statistics of MPAA, PIL, and PAD measurements according to study groups

	Group 1 (n = 27)	Group 2 (n = 27)	Group 3 (n = 27)	Group 4 (n = 27)
MPAA	109.8 ± 13.4	105.9 ± 9.9	110 ± 11	104.6 ± 12.1
PIL	33.6 ± 3.7	33.8 ± 2.7	34.4 ± 3	34.3 ± 3.2
PAD	12 ± 3.2	12.4 ± 2.2	12 ± 2.7	13.1 ± 2.4

Table 3.

Age-adjusted ANCOVA results for palatal measurements and homogeneity of regression slopes

Measurement	Effect	F	P	Partial η²
MPAA	Age	34.97	< 0.001	0.253
	Group	0.69	0.563	0.020
	Age x Group	0.62	0.603	0.018
PIL	Age	16.21	< 0.001	0.136
	Group	0.71	0.546	0.020
	Age x Group	0.43	0.735	0.013
PAD	Age	73.36	< 0.001	0.416
	Group	0.46	0.711	0.013
	Age x Group	1.21	0.309	0.035

ANCOVA analysis of covariance, η² eta squared; Age × Group, interaction term used to test the homogeneity of regression slopes assumption. Age was included as a covariate, and study group was included as a fixed factor. p < 0.05 was considered statistically significant

Table 4.

Age-adjusted estimated marginal means and 95% confidence intervals of palatal measurements according to study groups

Measurement	Group	Adjusted Mean	95% CI
MPAA	Group 1	108.065	104.073–112.056
	Group 2	105.294	101.369–109.219
	Group 3	108.463	104.348–112.579
	Group 4	108.413	103.557–113.269
PIL	Group 1	33.797	32.639–34.954
	Group 2	33.935	32.797–35.074
	Group 3	34.830	33.637–36.024
	Group 4	33.699	32.291–35.108
PAD	Group 1	12.531	11.742–13.320
	Group 2	12.573	11.797–13.349
	Group 3	12.556	11.743–13.370
	Group 4	12.229	11.269–13.188

Values are presented as estimated marginal means adjusted for age. Confidence intervals represent 95% confidence intervals obtained from the ANCOVA models. CI confidence interval

In study patients with unilateral ITH, bilateral ITH and absence of ITH, there was no significant difference between the mean MPAA, PIL and PAD values (Table 5). MPAA was higher in bilateral CB patients (108.2 (79.8–128.2)). PIL and PAD were higher in unilateral CB patients (34.9 (29.2–42.4) and 13.3 (8.9–17.4), respectively). Unilateral, bilateral CB and non-CB patients had no significant difference in palatal measurements (p > 0.05).

Table 5.

MPAA, PIL, and PAD measurements according to ITH status

	ITH
	Absent (n = 14)	Unilateral (n = 84)	Bilateral (n = 10)	F	p*
MPAA	108.7 ± 7.4	107.6 ± 12.8	105.8 ± 6.7	0.166	0.848
PIL	33.6 ± 1.7	34.1 ± 3.3	33.8 ± 3.1	0.206	0.814
PAD	12 ± 1.8	12.4 ± 2.9	12.6 ± 1.2	0.156	0.856

*ANOVA

In this study, a weak positive correlation was observed between DSCA and MPAA (r = 0.219; p = 0.023), whereas no significant correlation was found between DSCA and PIL or PAD (respectively: r=-0.079; p = 0.414 and r=-0.147; p = 0.128). Age showed a weak but statistically significant negative correlation with NSD angle (r = − 0.279, p = 0.003). Additional correlation analyses were performed to investigate the relationship between DSL and hard palate measurements in patients with NSD. Spearman correlation analysis demonstrated no significant correlations between DSL and MPAA (r = − 0.203, p = 0.141), PIL (r = 0.062, p = 0.658), or PAD (r = 0.266, p = 0.052). Diagnostic evaluation revealed no substantial violations of the assumptions of multiple linear regression in any of the three models. Residuals were approximately normally distributed according to histogram and normal probability (P–P) plots, scatterplots demonstrated homoscedasticity, tolerance values ranged from 0.871 to 0.970, VIF values ranged from 1.031 to 1.149, and Durbin–Watson statistics ranged from 1.882 to 2.002, indicating independence of residuals. Furthermore, when DSCA was entered into the multiple linear regression models as a continuous variable, it was not identified as an independent predictor of MPAA, PIL, or PAD after adjustment for age and other covariates. Age was the only variable significantly associated with MPAA, PIL, and PAD (p < 0.05), whereas gender, DSCA, ITH, and CB showed no significant associations (Table 6). Overall, the age-adjusted analyses consistently demonstrated that NSD, CB, ITH, and their combinations were not independently associated with MPAA, PIL, or PAD, whereas chronological age remained the only significant predictor of palatal morphology.

Table 6.

Multiple linear regression of predictors for MPAA, PIL, and PAD

		B(95% CI)	Beta	t	p	Zero order	Partial
MPAA	Constant	125.441 (100.092 - 150.791)		9.815	0.000
	Age	-1.804 (-2.433 - -1.174)	-0.513	-5.680	0.000	-0.519	-0.490
	Gender	0.323 (-3.66 - 4.307)	0.014	0.161	0.872	0.068	0.016
	DSCA	0.036 (-0.103 - 0.175)	0.045	0.512	0.610	0.190	0.051
	CB	1.241 (-2.906 - 5.388)	0.053	0.594	0.554	-0.023	0.059
	ITH	-0.598 (-4.963 - 3.767)	-0.024	-0.272	0.786	-0.054	-0.027
PIL	Constant	26.024 (18.775 - 33.272)		7.121	0.000
	Age	0.362 (0.182 - 0.542)	0.389	3.991	0.000	0.358	0.368
	Gender	0.891 (-0.248 - 2.03)	0.143	1.552	0.124	0.093	0.152
	DSCA	0.017 (-0.023 - 0.057)	0.082	0.862	0.391	-0.037	0.085
	CB	0.306 (-0.88 - 1.492)	0.049	0.512	0.610	0.105	0.051
	ITH	0.099 (-1.15 - 1.347)	0.015	0.157	0.876	0.021	0.015
PAD	Constant	2.961 (-2.045 - 7.967)		1.173	0.243
	Age	0.543 (0.418 - 0.667)	0.689	8.652	0.000	0.652	0.651
	Gender	0.386 (-0.401 - 1.172)	0.073	0.972	0.333	-0.010	0.096
	DSCA	0.014 (-0.013 - 0.042)	0.081	1.037	0.302	-0.119	0.102
	CB	-0.187 (-1.005 - 0.632)	-0.036	-0.452	0.652	0.069	-0.045
	ITH	0.108 (-0.754 - 0.97)	0.019	0.248	0.805	0.052	0.025

Discussion

CBCT is associated with higher radiation exposure compared with two-dimensional imaging methods. Due to children’s increased sensitivity to radiation and longer life expectancy, the cumulative effects of radiation are critical in justifying the use of CBCT. Therefore, CBCT imaging should be performed with dose optimization in accordance with the ALADAIP (As Low As Diagnostically Acceptable being Indication-oriented and Patient-specific) principle, taking into account the patient’s age and clinical indication [17]. Importantly, no CBCT scans were acquired specifically for this study; only previously obtained clinically indicated archival images were retrospectively evaluated. Nevertheless CBCT offers higher resolution, lower radiation exposure, and cost-effectiveness compared to Computed tomography (CT). Also, CBCT provides the ability to evaluate structures in three dimensions, revealing asymmetries and minor morphological differences [18]. These advantages allow for a detailed and accurate assessment of sinonasal variations and palatal dimensions [19]. This retrospective CBCT-based study evaluated the associations of anatomical variations and related conditions of the nasal cavity with palatal dimensions. The results showed that NSD, CB, and ITH did not demonstrate a statistically significant association with palatal depth or length in the study population. Patients with adenoid hypertrophy were excluded to minimize the influence of major upper airway obstruction factors and to better isolate the potential contribution of NSD, CB, and ITH to palatal morphology. Nevertheless, the retrospective design and sample-specific characteristics may have limited the detection of potential associations; therefore, the null hypothesis was not rejected within the constraints of this study.

As a result of NSD, airway obstruction, nasal dysfunction, and morphological changes in the maxillary structure may be observed. The narrowing of the maxillary arch and the increase in palatal depth are among the main consequences of NSD; moreover, a greater palatal depth contributes to a further increase in the severity of septal deviation [20]. In the study by Akbay et al. [14], a positive correlation was reported between NSD and palatal arch depth. The combination of CB and NSD may lead to further variations in the depth and length of the palatine bone [21].

In this study, MPAA values were lowest in group 4 (104.6 ± 12.1), while PAD values were highest in group 4 (13.1 ± 2.4). However, after adjustment for age using ANCOVA, no statistically significant differences were observed among the groups in MPAA, PIL, and PAD measurements (p > 0.05). Although some numerical differences were observed among the groups, particularly for MPAA and PAD, their clinical relevance should be interpreted cautiously. After age adjustment, the estimated marginal means and 95% confidence intervals showed considerable overlap among the groups. In addition, predefined clinically meaningful cutoff values for MPAA, PIL, or PAD were not available or used in the present study. Therefore, although these numerical differences may suggest a possible trend, the present findings do not provide sufficient evidence to confirm a clinically relevant independent association of NSD, CB, or their combination with palatal morphology after controlling for age.

From a clinical perspective, these findings suggest that isolated anatomical variations such as NSD or CB should not be considered reliable indicators of altered palatal morphology or be used alone when assessing maxillary development. Rather, evaluation of palatal morphology should be based on a comprehensive assessment that includes the patient’s age, overall craniofacial growth pattern, and functional clinical findings. The small effect sizes observed for the group factor in the ANCOVA models (partial η² = 0.013–0.020) further support this interpretation, indicating that NSD, CB, and their combination explained only a very small proportion of the variability in palatal measurements after adjustment for age. Consequently, although subtle numerical differences were observed, these anatomical variations appear to have limited independent clinical influence on palatal morphology within the pediatric population evaluated in the present study.

Similarly, Kajan et al. [21] reported that the decrease in PIL and MPAA in subjects with NSD and CB was not statistically significant. In contrast, Shetty et al. [13] reported that MPAA, PIL, and PAD measurements were significantly higher in the group without NSD and CB compared to the other groups. Differences among studies may be attributable to variations in age distribution, ethnicity, imaging protocols, and classification criteria, as well as differences in the severity of nasal cavity anatomical variations, study populations, and the inclusion of functional airway assessments. Importantly, anatomical variations such as NSD or CB do not necessarily correspond to clinically significant nasal airway obstruction or altered breathing patterns. The functional consequences of these anatomical findings depend on multiple factors, including the severity of the variation, compensatory anatomical adaptations, and the overall nasal airway condition. Therefore, the present findings should be interpreted as reflecting anatomical relationships identified on CBCT rather than functional nasal obstruction or respiratory impairment. Furthermore, previous studies have used heterogeneous methodologies and different definitions of NSD, CB, and ITH, making direct comparison difficult.

Inconsistencies between previous studies and the present findings may also reflect differences in study design and interpretation. For example, although both Shetty et al. [13] and Kajan et al. [21] evaluated the relationship between NSD, CB, and palatal morphology using CBCT, Shetty et al. [13] reported significant differences in MPAA, PIL, and PAD, whereas Kajan et al. [21] found no significant reductions in PIL or MPAA in subjects with NSD and CB.

Akbay et al. [14] reported in their study investigating the maxilla development according to NSD severity that MPAA and PAD measurements increased significantly as the degree of deviation increased, but no significant difference was found between PIL measurements. However, Savio and Nagesh [22] concluded that there was no significant change in PAD and PIL measurements as septal deviation increased, and that there was only a weak positive correlation with PAD. Similarly, in another study comparing palate measurements of subjects with and without NSD, no significant difference was found between the groups in the measurements of PIL and PAD [20]. In this study, a positive and significant correlation was found between DSCA and MPAA (r = 0.219; p = 0.023), while no significant relationship was observed between DSCA and PIL and PAD (r = -0.079; p = 0.414 and r = -0.147; p = 0.128, respectively). This finding suggests that the angle of septal deviation may be associated with the MPAA, while indicating that its relationship with PIL and PAD may be limited. Although a positive correlation was observed between the degree of nasal septal deviation and the MPAA, this association lost statistical significance in the multivariate regression model, suggesting that the observed relationship may be confounded by other variables included in the analysis. In addition to DSCA, DSL was evaluated to further characterize the extent of septal deviation among patients with NSD. DSL was not significantly correlated with MPAA, PIL, or PAD. Although a weak positive tendency was observed between DSL and PAD, this association did not reach statistical significance and should therefore be interpreted cautiously. Differences among studies may also be related to variations in the age distribution of the study populations. Because palatal morphology undergoes continuous developmental changes throughout childhood and adolescence, the inclusion of subjects between 6 and 18 years of age was considered appropriate to encompass the active period of maxillary growth. Histological and CBCT-based studies have demonstrated that midpalatal suture maturation continues throughout adolescence with considerable individual variability, and maxillary development is generally completed around 16 years in females and 17–18 years in males [23–25]. Therefore, restricting the sample to a narrower age range could have excluded part of the active developmental period. Nevertheless, craniofacial growth is not strictly linear during childhood and adolescence. To minimize the potential confounding influence of developmental variability, chronological age was incorporated as a continuous covariate in the ANCOVA models and as an independent variable in the multiple linear regression analyses, where age emerged as the only significant predictor of MPAA, PIL, and PAD. However, skeletal maturation indicators were not available because of the retrospective study design, and the sample size did not permit meaningful age-stratified subgroup analyses. These factors should be considered when interpreting the present findings.

In the present study, no significant differences in palatal measurements were observed among subjects with unilateral ITH, bilateral ITH, and the absence of ITH. Similarly, Shetty et al. [13] reported that the presence of ITH may be associated with palatal measurements, but whether it is unilateral or bilateral does not significantly influence these measurements. The other studies have shown that ITH can narrow the nasal airway independently of age and gender, modifying maxillofacial skeletal and, consequently, palatal development [26, 27]. The same degree of nasal airway narrowing may not develop in all cases of ITH. Moreover, the presence of other variations and the severity of ITH may also change their role in palatal development. These factors can be regarded as potential explanations for the absence of significant differences in palatal measurements in the present study. Furthermore, anatomical variations and related conditions do not necessarily reflect the degree of functional nasal impairment. Therefore, anatomical findings alone may not adequately represent the functional consequences of nasal cavity variations, which may account for the discrepancies between the present results and previous reports.

A limited number of studies in the literature investigated the relationship between CB and palatal measurements. According to the results of this study, there was no statistically significant difference in palatal measurements among the absence of CB, unilateral CB, and bilateral CB groups. Shetty et al. [13] demonstrated a significant association between CB and palatal measurements; in contrast, no statistically significant differences in palatal dimensions were observed between subjects with unilateral and bilateral CB. Previous studies have indicated that, even in the presence of bilateral CB, the conchae typically exhibit asymmetry, with one side being markedly larger than the other, and that NSD is more frequently observed on the side contralateral to the dominant CB [28–30]. This may account for the lack of statistically significant differences in palatal measurements observed in individuals with unilateral and bilateral CB.

Multiple regression analysis has revealed that age significantly associated with MPAA, PIL, and PAD, supporting the decisive role of growth and development processes in determining maxillary arch width, palatal length, and palatal depth. As age increases, MPAA decreases while PIL and PAD values increase. No significant association of gender, DSCA, CB, and ITH with these measurements was observed. While age during growth appears to be a significant factor in maxillary development, the potential contribution of anatomical variations and related conditions in the nasal cavity to palatal measurements could not be clearly demonstrated in this study. Although age-related craniofacial growth is an expected determinant of palatal morphology, the present findings suggest that isolated nasal cavity anatomical variations and related conditions alone may not be sufficient to alter palatal dimensions in growing individuals. These findings may help distinguish physiological growth-related changes from alterations potentially associated with localized anatomical variations. Because the proposed biological mechanism linking nasal cavity anatomical variations and related conditions to craniofacial development is thought to involve altered nasal function, the absence of functional and volumetric airway assessments limits the biological interpretation of the present findings. Therefore, the lack of significant associations observed in this study should be interpreted cautiously and only within the context of the anatomical variables evaluated.

In this study, a statistically significant difference in FOV distribution was observed among the groups (p = 0.001), primarily driven by the retrospective design and strict inclusion criteria, which led to the exclusion of a substantial number of CBCT scans. While this imbalance could theoretically pose a risk for selection bias, its impact on our primary outcomes is considered minimal. All measurements were performed on clearly defined, reliable skeletal landmarks that remain structurally unaffected by the scan’s outer boundaries, provided the hard palate is fully visualized. Furthermore, because all scans were acquired using the same CBCT device and voxel sizes were homogeneous across groups (p = 0.075), measurement standardization was strictly maintained. Regarding external validity, the varying FOV sizes reflect routine clinical practice in a university hospital setting, ensuring that our findings represent real-world clinical conditions rather than an artificial, strictly controlled experimental environment.

This study has several limitations that should be considered. Due to its retrospective design, functional and clinical parameters such as tongue position, nasal airflow, airway resistance, breathing pattern, mouth breathing habits, functional nasal obstruction, and airway volume could not be evaluated. Therefore, the present findings should be interpreted as being limited to CBCT-based anatomical variables, including NSD, CB, and ITH, and should not be generalized to functional nasal obstruction or respiratory patterns. In addition, a substantial number of CBCT examinations were excluded because the field of view did not completely include the anatomical structures required for the planned measurements. Although this exclusion criterion was necessary to ensure measurement accuracy and methodological consistency, it may have introduced selection bias by preferentially including examinations with adequate image coverage. Consequently, the external validity and generalizability of the present findings should be interpreted with caution. In addition, age distribution among the groups was not fully homogeneous, which may have influenced palatal measurements during growth. Furthermore, chronological age was used as a surrogate for developmental status because skeletal maturation indicators were not available in this retrospective dataset. Therefore, developmental stage-specific analyses could not be performed and residual developmental heterogeneity may still have influenced the observed associations. CBCT acquisition parameters were also not fully homogeneous because of the retrospective design. Although FOV distribution differed among the study groups, voxel size distribution did not; since all scans were obtained using the same CBCT system and measurements were based on clearly identifiable skeletal landmarks, the potential influence on measurement accuracy was considered limited, but cannot be completely excluded. Furthermore, NSD and CB were classified primarily according to their presence or absence, and ITH was categorized as absent, unilateral, or bilateral without further severity grading. Therefore, potential dose–response relationships between the severity of these anatomical variations and palatal morphology could not be evaluated. Future studies using larger, age-balanced cohorts, standardized severity classifications for NSD, CB, and ITH, together with functional and volumetric airway assessments, are needed to better clarify the relationship between nasal cavity anatomical variations, nasal function, and palatal development. In addition, due to the retrospective nature of the study, detailed information regarding previous nasal/pharyngeal treatments and genetic or ethnic variability, which may potentially influence craniofacial morphology, could not be comprehensively evaluated. Finally, all image evaluations were performed by a single calibrated observer. Although excellent intra-observer agreement and low measurement error were demonstrated, inter-observer reliability was not assessed. Therefore, the potential influence of observer-related variability cannot be completely excluded.

Conclusion

Within the limitations of this retrospective CBCT-based anatomical study, no significant independent associations were detected between nasal septum deviation, concha bullosa, inferior turbinate hypertrophy, and MPAA, PIL, or PAD in pediatric patients after adjustment for age. Age was the main significant predictor of palatal measurements in this sample. However, because functional parameters such as nasal airflow, airway resistance, breathing pattern, mouth breathing habits, and airway volume were not assessed, these findings should be interpreted as limited to the anatomical variables evaluated and should not be generalized to functional nasal obstruction or respiratory patterns.

Authors’ contributions

NDŞ: Resources, Data Curation, Writing - Original Draft, Writing - Review & EditingMÇ: Conceptualization, Methodology, Formal analysis, Writing - Original Draft, Writing - Review & Editing, Visualization, SupervisionAll authors reviewed the manuscript.

Funding

The research was not supported.

Data availability

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Human rights statements: All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008.Ethics Committee Approval: XXX University Faculty of Medicine Clinical Research Ethics Committee, 23-KAEK-235).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.