Correlation Between Severity of Obstructive Sleep Apnea and Dental Arch Form in Adults

Objectives: This study examines the relationship between maxillary morphology and the severity of obstructive sleep apnea (OSA) in adults, with a focus on intermolar distance (IMD) and palatal height (PH) as predictive factors. Methods: A retrospective observational study was conducted at private orthodontic practices in Sydney, Australia. A total of 100 adults (50 OSA patients and 50 controls) were included. OSA diagnosis and severity were confirmed via hospital-based polysomnography. Digital maxillary models were analyzed using the Medit Link software (version 3.2.0; Medit Corp., Seoul, Republic of Korea), and IMD and PH were measured. Statistical analyses included one-way ANOVA and linear regression modeling, with adjustments for age and sex. Results: The OSA group exhibited significantly narrower IMD (28.96–35.01 mm) and higher PH (21.68–29.56 mm) compared to the control group (IMD: 36.35–41.50 mm; PH: 18.57–23.51 mm). A negative correlation was observed between IMD and PH across all groups. Linear regression analysis demonstrated a strong association between these craniofacial parameters and OSA severity (R2 = 0.76, p < 0.001). IMD was negatively correlated with the Apnea-Hypopnea Index (AHI) (p = 0.003), while PH was positively correlated (p < 0.001). The inclusion of demographic variables did not significantly enhance the predictive model. Conclusions: Maxillary morphology associates with OSA severity, with narrower IMD and greater PH linked to higher AHI.