We recommend CPAP if you have already tried an oral appliance, and didn't get used to it, or it was ineffective. We also recommend CPAP if you have ongoing dental treatment such as braces, aligners, or dental implants. Your teeth and gums must be in good shape when using an oral appliance, and we recommend you have visited your dentist in the past year, and have no active dental issues. If that is NOT the case, then we recommend CPAP. If your sleep apnea is extremely severe, we also suggest you try CPAP first, unless you are opposed to it, or have claustrophobia, or have failed CPAP treatment in the past.