Abstract
Objective
To assess positional and morphological characteristics of the glenoid fossa in patients with and without craniofacial asymmetry using cone-beam computed tomography (CBCT), and to identify structural adaptations associated with temporomandibular joint (TMJ) compensation.
Methods
An observational study analyzed CBCT scans from 47 patients: 36 with facial asymmetry and 11 symmetric controls. Morphometric measurements (vertical, anteroposterior, and transverse positions; angular and depth parameters) were taken in sagittal, coronal, and axial planes using standardized anatomical references. Statistical analyses included independent and t-tests, Wilcoxon signed-rank tests, multivariate analysis of variance (MANOVA), and Pearson correlations.
Results
Asymmetric patients showed significantly greater anteroposterior displacement of the glenoid cavity (anteroposterior location of the glenoid cavity in millimeters (APCGmm): 8.42 ± 8.01 mm vs. 4.19 ± 2.41 mm, p = 0.011) and reduced axial angulation (axial angulation of the glenoid cavity in degrees (AAGC°): 62.96° ± 8.24° vs. 66.01° ± 4.18°, p = 0.032) compared with symmetric controls. Transverse angular variation (transverse angulation of the glenoid cavity in degrees (TMGC
Conclusion
CBCT-based evaluation reveals distinct morphological adaptations in the glenoid fossa of asymmetric patients, including anterior displacement, rotational shifts, and contralateral deepening. These findings support the concept of compensatory TMJ remodeling in response to craniofacial imbalance. The integration of three-dimensional morphometric and angular data enhances diagnostic precision and can inform orthodontic and surgical planning.
Keywords
Introduction
Craniofacial asymmetry is a multifactorial condition resulting from developmental anomalies, trauma, or skeletal–dental discrepancies, often linked to abnormal growth of the condyle or mandibular ramus.1–4 These asymmetries activate compensatory dentoalveolar, skeletal, and neuromuscular mechanisms to preserve function and aesthetics. 5 Over time, such adaptations are reflected in the morphology of the temporomandibular joint (TMJ) and glenoid fossa.5–8
Accurate morphometric analysis relies on stable cranial landmarks—such as the infraorbital margin, posterior clinoid processes, and crista galli—due to their embryological stability and minimal remodeling during growth.9–11 The glenoid fossa exhibits morphological plasticity in response to mandibular positioning, with asymmetry-related depth differences up to 2.4 mm reported between sides.12–14 Additionally, vertical facial pattern, skeletal class, and malocclusion influence condylar position and fossa shape.15–18
TMJ remodeling occurs in both symptomatic and asymptomatic patients. Mandibular repositioning may relieve temporomandibular disorder (TMD) symptoms and promote structural changes, supporting its use as a preventive measure during growth.19–24 Detailed evaluation of condyle–fossa relationships using angular and dimensional parameters has advanced understanding of skeletal asymmetries.25–28
Recent advances in three-dimensional (3D) imaging and artificial intelligence-assisted diagnostics have enhanced the precision of evaluating TMD and craniofacial asymmetry.29–32 This study uses cone-beam computed tomography (CBCT) to assess and compare the morphometric characteristics of the glenoid fossa in symmetric and asymmetric patients. It focuses on measuring dimensions and angular orientation on both the affected and unaffected sides in asymmetric individuals, compared to both sides in symmetric controls. Accurate and standardized assessment may improve diagnosis, guide personalized treatment in orthodontics and maxillofacial surgery, and support the management of TMJ-related pain through optimized, evidence-based interventions.33–36
Methods
Study design
This was an observational, cross-sectional, descriptive, and comparative study designed to evaluate the morphological and positional characteristics of the glenoid fossa in symmetric and asymmetric patients using CBCT. The study was conducted at the Centro de Estudios Superiores en Ortodoncia (CESO), Mexico. Patients were consecutively selected and divided into two groups: those with facial asymmetry (asymmetric group) and those without (symmetric group), based on standardized clinical and radiographic evaluations.
The study was conducted in accordance with the principles of the current Helsinki Declaration of 1975, as revised in 2024, as well as local, regional, and international regulations pertaining to clinical research, including Mexican Law on Biomedical Research. Ethical approval was obtained from the Medical Ethics Committee of the CESO, Mexico (code: 12.2024_C.E.S.O). All personal data of patients have been deleted. This was a retrospective study, and informed consent was not required. The reporting of this study conforms to STROBE guidelines. 37
Patient selection
CBCT records from a total of 47 patients were included. Patients were assigned to the asymmetric (n = 36) or symmetric group (n = 11) by two expert orthodontists using consensus-based criteria assessing facial asymmetry via Menton deviation and radiographic evidence. The criteria for eligibility were described in Supplemental Table 1, and variables used in the study are described in Supplemental Table 2. The sample had a mean age of 17.6 years (range: 10–50), with a predominance of late adolescents and young adults; age stratification was not performed. Facial asymmetry was defined as a Menton deviation of ≥3 mm from the midsagittal plane, confirmed both clinically and radiographically, and/or the presence of angular discrepancies >2° or linear discrepancies >2 mm between hemi-faces.
Imaging protocol
CBCT scans were obtained using a Sirona Galileos Comfort unit (Sirona Dental Systems, Bensheim, Germany), located at CESO (Mexico), under the following parameters:
Field of view: 15 × 15 cm Voxel size: 0.25 mm Voltage: 120 kV Current: 5–8 mA Acquisition time: 20 s Positioning: Natural head position, with the Frankfort horizontal plane parallel to the floor and centric occlusion.
All images were exported in Digital Imaging and Communications in Medicine format and analyzed using Galileos Viewer software, calibrated to a 1:1 pixel ratio.
Reference planes and anatomical landmarks
Anatomical reference planes were selected based on embryologic stability and clinical relevance (Supplemental Figure 1):
Infraorbital plane Crista galli line Posterior clinoid processes
These planes allowed for accurate 3D measurements in axial, sagittal, and coronal views.
The infraorbital plane (the lowest point of the orbits) and a perpendicular to the crista galli in the coronal plane were used. In the sagittal view, the reference vertical plane was located behind the posterior clinoid processes. A unilateral reference was set by placing the intersection of the vertical and horizontal lines in the sagittal and coronal planes at the deepest part of the glenoid cavity.
Definition of the side of asymmetry: Rather than classifying by shorter or deviated sides, the term “side of asymmetry” was used to reflect the hemisphere demonstrating morphologic deviation—acknowledging the complexity of growth-related deviations that could result from elongation, height discrepancy, or transverse shift.
Image processing and measurements: Measurements were performed in sagittal, coronal, and axial planes by two calibrated examiners. Spatial referencing enabled simultaneous three-plane localization. The following positional and morphological measurements of the glenoid fossa were recorded (Table 1):
Morphometric Differences in Glenoid Fossa by Group.
ACGmm: glenoid cavity height in millimeters; APCGmm: anteroposterior location of the glenoid cavity in millimeters; TCGmm: transverse location of the glenoid cavity in millimeters; PCGmm: posterior displacement of the glenoid cavity in millimeters; ATCG°: anterotilt of the glenoid cavity in the sagittal plane; TMGC°: transverse angulation of the glenoid cavity in degrees; AAGC°: axial angulation of the glenoid cavity in degrees.
Linear measurements (in mm): Two calibrated examiners independently repeated measurements on a random 20% subsample. Intraclass correlation coefficients for intra- and inter-examiner agreement exceeded 0.90 across all variables, indicating excellent reproducibility.
Vertical position of glenoid cavity Anteroposterior location of the glenoid cavity in millimeters (APCGmm) (anteroposterior position) TPGCmm (transverse position) VMGCmm (vertical morphology)
Angular measurements (in degrees)
AMGC° (anteroposterior morphology)
Medial rotation of the glenoid cavity in the transverse plane (transverse angulation of the glenoid cavity in degrees (TMGC°)) (transverse morphology)
Axial angulation of the glenoid cavity relative to the cranial base (axial angulation of the glenoid cavity in degrees (AAGC°)) (axial angulation)
Measurements were bilateral in symmetric patients (right and left) and unilateral in asymmetric patients (side of asymmetry vs. contralateral).
Step-by-step workflow of the study: The study followed a systematic stepwise protocol:
Selection of eligible patients through clinical and radiographic screening. Acquisition of high-resolution CBCT scans under standardized conditions. Anatomical landmark identification and image orientation using validated reference planes. Positional and morphological measurements of the glenoid cavity performed by two calibrated examiners. Statistical analysis and interpretation of results. An a priori power analysis (effect size 0.8, α = 0.05) indicated a minimum of 26 participants; the final sample (n = 47) exceeded this requirement.
Positional parameters in millimeters indicate linear measurements in vertical, anteroposterior, and transverse planes. Morphological and angular parameters in degrees reflect the orientation and angulation of the glenoid fossa. In symmetric patients, measurements were recorded for both right and left sides. In asymmetric patients, data were taken from the asymmetry side and the contralateral side.
Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics software (Version 27.0; IBM Corp., Armonk, NY, USA). Descriptive statistics, including means, standard deviations, and ranges, were calculated for each morphometric variable. Descriptive statistics: mean, standard deviation, and range for each variable. Normality of the data distribution was assessed using the Shapiro–Wilk test. For inter-group comparisons between symmetric and asymmetric subjects, unpaired Student's t-tests were employed when data followed a normal distribution; otherwise, Wilcoxon signed-rank tests were applied. For intra-group comparisons within the asymmetric group (asymmetry side vs. contralateral side), paired samples t-tests were used for normally distributed variables, and Wilcoxon signed-rank tests for non-normal data. In addition, a multivariate analysis of variance (MANOVA) was performed to assess global differences across multiple dependent variables simultaneously, considering the asymmetry condition as the independent factor. All statistical tests were two-tailed, and a p-value <0.05 was considered statistically significant
Results
This study was conducted with a sample of 47 patients, 36 in the asymmetric group (76.6%) and 11 in the symmetric group (23.4%). Among the asymmetrical patients, 28 were female (77.8%) and eight were male (22.2%); in the symmetric group, eight were female (72.7%) and three were male (27.3%). The mean age of the entire cohort was 17.6 years, with a range from 10 to 50 years. Facial asymmetry was more frequently observed on the right side (n = 18, 51.4%) than on the left side (n = 17, 48.6%). All patients underwent high-resolution CBCT imaging under standardized conditions. Measurements were obtained using SIRONA software with 1:1 calibration, and the dataset was divided and analyzed according to group, side of asymmetry, and contralateral correspondence. Morphometric analysis of the glenoid fossa showed significant group differences in positional and angular measurements, as detailed in Table 1.
Graphical representation
Bar plots and box plots were generated to visually compare means and variances for each variable across symmetric and asymmetric groups. These plots confirmed the greater dispersion in the asymmetric group for anteroposterior location of the glenoid cavity (APCGmm) and AAGC°, supporting the hypothesis of altered positioning and angulation in patients with facial asymmetry.
Interpretation of findings
Significant anteroposterior differences of APCGmm suggest that the glenoid cavity is more anteriorly displaced in asymmetric patients. Additionally, variations in transverse and axial angulation (TMGC° and AAGC°) point to rotational adaptations of the fossa that may reflect compensatory remodeling.
These results align with theories of skeletal plasticity and remodeling associated with functional shifts in occlusion and mandibular deviation. Importantly, the absence of significant vertical differences suggests that asymmetry manifests more prominently in horizontal and axial planes than in vertical positioning. All statistical tests were two-tailed, and a p-value <0.05 was considered statistically significant.
Glenoid cavity
Glenoid cavity height in millimeters (ACGmm): A greater range was observed in asymmetrical patients compared to symmetrical ones, particularly on the side opposite the asymmetry (Supplemental Table 3 and Figures 2 and 3). The highest average was found in asymmetrical patients on the side opposite the asymmetry.
APCGmm: Results indicate a higher average, range, and standard deviation in asymmetrical patients (Supplemental Table 4 and Figures 4 and 5).
Transverse location of the glenoid cavity in millimeters (TCGmm): In asymmetrical patients, a greater range is observed in the transversal location, especially further from the midline on the side opposite the asymmetry (Supplemental Table 5 and Figures 6 and 7).
Depth of the glenoid cavity (posterior displacement of the glenoid cavity in millimeters (PCGmm)): The range in asymmetrical patients is greater, particularly on the side opposite the asymmetry, indicating a deeper cavity in these patients (Supplemental Table 6 and Figures 8 and 9).
Anteroposterior angulation of the glenoid cavity (APCG°): The cavity is flatter in the anterior zone and more vertical in the posterior zone on the side opposite the asymmetry (Supplemental Table 7 and Figures 10 and 11).
Transversal angulation of the glenoid cavity (anterotilt of the glenoid cavity in the sagittal plane (ATCG
Axial angulation of the glenoid cavity(AAGC°): A greater angulation was observed on the side of the asymmetry in asymmetrical patients, indicating a more external position of this side of the mandibular condyle (Supplemental Table 9 and Figures 14 and 15).
Quantitative analysis of glenoid cavity morphometrics: Comparative visualization and multivariate correlation
To better understand the morphometric alterations of the glenoid cavity in asymmetric versus symmetric patients (Supplemental Table 10). We conducted a series of complementary visual and statistical analyses, including bar plots, boxplots, Pearson correlation matrices, and hierarchical clustering.
Groupwise comparison of morphometric means
A comparative bar plot summarizes the mean values of seven morphometric parameters between symmetric and asymmetric patients: vertical position (ACGmm), anteroposterior position (APCGmm), transverse position (TCGmm), posterior cavity depth (PCGmm), and angular measurements including sagittal (ATCG°), transverse (TMGC°), and axial (AAGC°) orientations.
APCGmm and AAGC° emerged as the most distinguishing variables between groups, showing marked increases in anteroposterior displacement and axial angulation among asymmetric patients. Conversely, ACGmm presented minimal differences, suggesting that vertical positioning of the glenoid cavity is less sensitive to asymmetrical growth patterns. This plot highlights the primary morphometric dimensions affected by craniofacial asymmetry and reinforces their potential diagnostic value. Figure 1 illustrates the differences in mean glenoid fossa morphometric measurements between symmetric and asymmetric groups.

Comparison of glenoid fossa measurements by group.
To explore the interdependencies among glenoid fossa measurements, a Pearson correlation heatmap was constructed (Figure 2). Strong positive correlations were observed between APCGmm and AAGC°, suggesting that anteroposterior advancement of the glenoid cavity may be biomechanically offset by increased axial angulation. Furthermore, ATCG° and TMGC° demonstrated moderate to strong positive correlations, implying an interlinked sagittal-transverse adaptation. ACGmm, in contrast, showed minimal correlation with other dimensions, reinforcing its relative independence from asymmetry-induced changes. These findings support the hypothesis that asymmetry primarily affects horizontal displacement and rotational remodeling rather than vertical structure.

Pearson correlation heatmap revealing interdependencies among glenoid fossa measurements, highlighting compensatory axial and transverse angular adaptations in response to horizontal displacement.
A focused scatter plot analysis within the asymmetric cohort revealed a moderate inverse correlation between APCGmm and AAGC° (Figure 3). As the anteroposterior displacement increased, axial angulation tended to decrease. This trend may reflect a rotational compensation mechanism to preserve joint congruency and functional load distribution. Such inter-variable interactions suggest a complex adaptive architecture within the TMJ responding to craniofacial imbalance. Together, these multivariate and graphical analyses reinforce the structural complexity and diagnostic significance of glenoid cavity alterations in facial asymmetry, supporting the use of CBCT-based morphometrics in orthodontic and maxillofacial evaluation.

Inverse correlation between anteroposterior displacement and axial angulation in asymmetric patients, suggesting compensatory rotational adaptation of the glenoid cavity.
Discussion
This study found significant differences in the morphometric characteristics of the glenoid cavity and condylar positioning associated with craniofacial asymmetry. Notable discrepancies were observed in the APCGmm and angular variables (TMGC° and AAGC°), both between deviated and non-deviated sides and between asymmetric and symmetric groups. Given the observational, descriptive, cross-sectional design, causal inference cannot be established; therefore, AAGC° may represent a cause, a consequence, or an adaptive marker of asymmetry.
These findings are consistent with the previous literature reporting positional and morphological alterations in the TMJ of patients with facial asymmetry. Several studies have demonstrated adaptive displacement of the glenoid fossa and the mandibular condyle in the anteroposterior direction under asymmetric conditions. For instance, in patients with mandibular deviation, the glenoid fossa on the deviated side is significantly more posterior and inferior compared to the contralateral side and symmetric controls.38,39 Our study similarly found a posterior displacement of the glenoid cavity in the deviated side, consistent with findings in patients with unilateral condylar hyperplasia, where the hypertrophic condyle displaces the glenoid fossa backward.40,41
Katsavrias and Halazonetis also reported sagittal condylar positional differences depending on skeletal class, where in class III discrepancies, the condyle tends to be positioned more centrally, whereas in class II division 2, it is located more posteriorly. 42 Collectively, these findings and ours suggest that the TMJ undergoes remodeling to accommodate unilateral growth patterns, thereby contributing to craniofacial asymmetry.
In terms of angular adaptations, our results showed significant differences in condylar and glenoid cavity angles (TMGC° and AAGC°) between deviated and contralateral sides, which aligns with recent 3D studies documenting angular disparities in asymmetric patients. Oh et al. 38 found that both axial condylar and fossa angles are greater on the deviated side, indicating rotational adaptation.16–43 These angular shifts are considered compensatory mechanisms in response to mandibular deviation, helping maintain joint congruency.
Functionally, condylar trajectories and sagittal inclinations differ significantly between sides in asymmetric individuals. Previous research has shown that the sagittal condylar path is steeper on the deviated side, while transverse inclination may not differ significantly. 44 Our study supports this, with broader dispersion and variability in angular parameters in the asymmetric group, which reflects compensatory adaptation. Although some discrepancies exist in the literature depending on sample characteristics, such as skeletal class, the general trend supports our observation of increased variability and rotation in angular parameters among asymmetric patients. 45
Statistical analyses in our study also align with prior morphometric reports showing bilateral differences in condyle and glenoid fossa size, surface area, and anterior-posterior length in asymmetric individuals. 46 For example, the volume and surface area of the glenoid fossa are typically smaller on the deviated side, and the articular eminence on that side exhibits a steeper angle. These findings are supported by our observation of reduced APCG and increased TMGC in the deviated group.
Furthermore, several studies have identified morphological differences in the condyles themselves. For instance, asymmetric patients often have a larger condyle on the deviated side, with an anteriorly flattened and posteriorly convex shape. 47 These differences appear to be directly correlated with asymmetry development.45–47 Such incongruencies may reduce joint surface contact and increase mechanical stress, ultimately inducing remodeling. This trend is reflected in our boxplots, which show consistent unilateral dominance and broader value dispersion.45–47
Another novel contribution of this study is the exploration of correlations between articular morphology and mandibular function. The correlation heatmap, which demonstrated moderate inverse relationships between APCGmm and AAGC°. This implies that as the glenoid cavity moves anteriorly, axial tilt compensates to maintain functional congruity.35–40 Similar associations have been discussed in studies of protrusive movements and fossa shape. Previous research has shown that smaller glenoid fossae on the deviated side are associated with steeper sagittal condylar paths, and smaller condyles with longer protrusive movements. 44 We found similar relationships, suggesting that the TMJ adapts kinematically to compensate for structural discrepancies. These dynamics were confirmed using MANOVA, which showed significant global differences between symmetric and asymmetric groups.
Clinically, these structural adaptations may affect joint loading and long-term joint health. Prior reports show narrower joint spaces and more anterior condyle positions in asymmetric patients, possibly predisposing them to disc displacement or joint sounds.39,40 Nonetheless, the TMJ has a strong remodeling capacity. Under unilateral loads, adaptive changes in both the condyle and fossa can preserve function.48,49 For instance, Petronis et al. 50 describe the remodeling process as a balance-preserving mechanism. Our findings, including the absence of major dysfunction in most cases, support the notion of functional compensation.
From a therapeutic standpoint, awareness of such asymmetries is critical. Surgical or orthodontic treatments must anticipate possible post-treatment remodeling. The literature shows that condylar direction changes during orthognathic surgery affect resorption and apposition patterns, which necessitate long-term monitoring. 51 Therefore, integrated TMJ evaluation is essential for optimal management.
Our findings corroborate and extend prior research, incorporating rare angular measurements and multivariate analysis. The study reinforces the biomechanical complexity of asymmetry, showing consistent trends with well-cited works. Future research should include larger, stratified samples and long-term follow-up to better understand adaptive trajectories. The diagnostic value of 3D imaging in evaluating facial asymmetries. A detailed morphometric analysis of the glenoid fossa can inform more precise treatment planning in orthodontics and orthognathic surgery, particularly in cases involving mandibular deviation and TMJ dysfunction. Future work should incorporate longitudinal and dynamic imaging to establish temporal relationships, evaluate the predictive value of preoperative metrics for surgical relapse, define clinically meaningful angular cutoffs, and leverage artificial intelligence for automated glenoid fossa segmentation.
Limitations
A key limitation of this study is the small sample size, particularly within the symmetric group. This may limit the generalizability of the findings and reduce the statistical power to detect subtle differences across some variables. Furthermore, the cross-sectional design precludes evaluation of how these morphological characteristics evolve over time or in response to treatment. Future studies should include larger, more balanced samples and consider longitudinal designs to validate and expand upon these findings. The incorporation of machine learning models could also enhance detection and prediction of asymmetry-related joint adaptations. The wide age range of participants (10–50 years) may have introduced growth-related variability, despite the predominance of late adolescents and young adults. As the cohort was asymptomatic, morphology–symptom correlations could not be evaluated. CBCT offers static morphological assessment and does not capture dynamic joint function. The cross-sectional design precludes causal inference, and the lack of post-treatment follow-up limits the ability to assess the predictive value for surgical relapse. In some cases, delineating the thin cortical border of the fossa was challenging; however, the use of digital magnification, stable cranial landmarks, and examiner consensus helped minimize measurement error.
Conclusion
This study performed a 3D assessment of the glenoid cavity in 47 patients with and without craniofacial asymmetry using CBCT imaging. In asymmetric patients, significant differences were observed in anteroposterior displacement as well as in axial and transverse angles, suggesting adaptive remodeling secondary to mandibular imbalance. Greater variability was also noted in height, depth, and angular orientation, accompanied by structural compensation on the contralateral side. Multivariate analyses confirmed global morphometric differences, while correlation maps demonstrated biomechanical interdependence among spatial axes. These results underscore the importance of individualized morphometric evaluation to ensure accurate diagnosis and personalized treatment planning in patients with craniofacial asymmetry.
Supplemental Material
sj-docx-1-sci-10.1177_00368504251381557 - Supplemental material for Tomographic assessment of glenoid fossa morphology and position in symmetric and asymmetric patients
Supplemental material, sj-docx-1-sci-10.1177_00368504251381557 for Tomographic assessment of glenoid fossa morphology and position in symmetric and asymmetric patients by Arturo Arbelaez-Ramirez, Eduardo Tuta-Quintero and Daniel Botero-Rosas in Science Progress
Footnotes
Acknowledgements
The authors are most thankful for the Universidad de La Sabana and the Centro de Estudios Superiores en Ortodoncia.
Ethics approval statement
The study was conducted in accordance with the principles of the current Helsinki Declaration of 1975, as revised in 2024, as well as local, regional, and international regulations pertaining to clinical research, including Mexican Law on Biomedical Research. Ethical approval was obtained from the Medical Ethics Committee of the CESO, Mexico (code: 12.2024_C.E.S.O).
Consent to participate
This is a retrospective database analysis study, and consent to participate was waived by the institutional review board.
Author contributions
AAR, ETQ, and DBR contributed to the conception and design. They also supervised the whole process, data collection, analysis, and interpretation of the patient data. ETQ and DBR wrote major parts of the manuscript, and AAR revised it. All authors read and approved the final manuscript.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Universidad de La Sabana (Grant: MEDPHD-76-2025) and Centro de Estudios Superiores en Ortodoncia.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data availability statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Supplemental material
Supplemental material for this article is available online.
References
Supplementary Material
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