Dental crowding and a narrow palate can reduce airway size; in select cases

https://www.scribd.com/document/999458283/Types-of-Sleep-Apnea-Oral-Appliances-Which-One-Fits-Your-Needs-228544

Dental crowding and a narrow palate can reduce airway size; in select cases, palatal expansion may improve airflow and reduce snoring and apneas.