The interrelationship of TMJ morphology, craniofacial structure, and airway dimensions in patients with disc displacement

This study aimed to comprehensively analyse the interrelationships between temporomandibular joint (TMJ) morphology, craniofacial skeletal patterns, and oropharyngeal airway dimensions in patients with TMJ disc displacement (TMJ DD). Based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and subsequent MRI confirmation, this retrospective study included 91 adult patients with TMD DD. These patients were then categorized into three groups.: Bilateral Normal disc position (BN, n = 36), Disc Displacement with Reduction (DDR, n = 25), and Disc Displacement without Reduction (DDWR, n = 30). All participants underwent cone-beam computed tomography (CBCT) and cephalometric analysis of craniofacial structure and three-dimensional assessment of TMJ morphology (including joint spaces, fossa dimensions, and condylar inclination) and oropharyngeal airway volume (OPV) and area (OPA). Statistical analyses included one-way ANOVA/Kruskal–Wallis tests for group comparisons, Spearman's correlation to assess bivariate relationships, and multiple linear regression (MLR) to identify independent predictors of airway dimensions while controlling for confounders. Significant differences were observed in craniofacial, TMJ characteristics, and oropharyngeal airway dimensions among the groups. The DDWR group exhibited a retrognathic and hyperdivergent skeletal pattern (larger ANB, smaller SNB, higher FMA; p < 0.05). The DDR group demonstrated a significantly steeper anterior condylar inclination and a more posteriorly positioned condyle. Crucially, oropharyngeal dimensions were significantly smaller in the DDR group compared to the BN group (OPV: 7688.56 ± 1770.14 mm3 vs. 10,562.47 ± 4185.89 mm3, p = 0.029; OPA: 410.76 ± 77.65 mm2 vs. 513.44 ± 145.21 mm2, p = 0.018). Correlation and MLR analyses revealed that a constricted airway was associated with mandibular retrognathism, specific TMJ features, and reduced vertical facial dimensions. Notably, glenoid fossa height was a significant positive predictor for both OPV and OPA. TMJ DD is associated with specific craniofacial patterns and reduced oropharyngeal airway dimensions. These findings underscore a significant association within the TMJ-craniofacial-airway complex, advocating for an integrated clinical approach in diagnosing and treating temporomandibular disorders and airway compromise.