Evaluation of Cephalometric Indices in Patients with Obstructive Sleep Apnea in Comparison with Healthy Individuals

Study objectives: This study aimed to evaluate the cephalometric parameters related to obstructive sleep apnea (OSA). Methods: Twenty-four patients with OSA diagnosis and Apnea-Hypopnea Index (AHI) ≥15 in overnight polysomnography were recruited. A similar number of control participants were selected based on the absence of OSA clinical presentations through evaluation with the Epworth Sleepiness Scale and STOP-Bang questionnaires. Two groups were matched for age, sex, and body mass index. The standardized upright lateral cephalograms of all participants were obtained; afterward, skeletal and soft tissue landmarks were traced and digitized. Results: We observed that in patients with OSA, mandibular ramus length was significantly bigger (p = 0.02), and the mandibular plane made a greater angle with the line passing through the nasion and the sella (p < 0.001). They had a retro-positioned mandible (p < 0.001), and the hyoid bone was placed inferiorly (p < 0.001) compared to control participants. Regarding the differences related to soft tissue, they had elongated tongue (p < 0.001) and soft palate (p < 0.001). The ANB angle was negatively correlated with diseases severity (r = −0.49, p = 0.013). Among different cephalometric measurements, the H-MP and TL with the cut-off values of 14 and 67 mm had the highest power to predict OSA. Conclusions: The patients with OSA exhibited longer soft palate and tongue, inferiorly positioned hyoid bones, and retruded and longer mandible. The disease severity was mainly related to the retruded mandible. Moreover, hyoid bone position and tongue length were the most reliable measures to predict OSA.