This study aimed to assess the upper airway measurements in adult patients without prior orthodontic treatment, categorized equally according to their skeletal classification. Methods: In this retrospective cross-sectional investigation, lateral cephalometric radiographs from adults seeking orthodontic consultation were analyzed. Cephalometric tracings were carried out using specialized software, and descriptive statistics were computed for each parameter. Comparisons of cephalometric values across skeletal classes were performed, followed by linear regression analyses examining the relationship between airway dimensions, cephalometric variables, sex, and age. A p-value of < 0.05 was considered statistically significant. Results: Radiographs from 120 subjects were evaluated. The nasopharyngeal length (NL) and depth (PD) were markedly shorter in individuals with skeletal class III patterns (p < 0.05). The superior pharyngeal airway space (SPAS) was significantly reduced in class III compared to class II participants (p < 0.05), while class I subjects showed a smaller mean airway space (MAS) than those in class II (p < 0.05). Palatal length (PL) was notably greater in class I (p < 0.05). Regression analysis revealed that both the sella-nasion-A point angle (SNA) and Riedel’s A–N–B angle (ANB) significantly influenced NL and PD values (p < 0.05). Conclusions: Individuals with class III skeletal patterns present shorter nasopharyngeal dimensions, indicating that sagittal skeletal variations may be associated with changes in upper airway anatomy.
