Impact of 3D airway geometry on airflow in adults with different skeletal classes: A CFD analysis

The relationship between craniofacial pattern and upper airway function remains incompletely understood.

This study investigated differences in upper pharyngeal airway morphology and airflow characteristics among young adults with skeletal Classes I, II, and III according to the ANB angle. Three-dimensional (3D) models were reconstructed from CBCT images. Morphological parameters, including total airway volume and minimum cross-sectional area (mCSA), were measured. Computational fluid dynamics simulations were performed to evaluate airflow velocity and maximum pressure within the human upper airway (HUA).

Class II subjects exhibited significantly reduced airway volume and mCSA, compared with Class I and Class III subjects. These anatomical differences were associated with higher airflow velocity and increased airway suggesting greater airflow resistance. In contrast, individuals with Class III demonstrated larger airway spaces with lower airflow velocity and pressure.

Skeletal pattern significantly influences both airway morphology and airflow behavior. Class II individuals exhibit narrower airways and higher resistance, whereas Class III individuals present more favourable airway characteristics.