How effective are the oral appliances in treating snoring and sleep apnea?

Oral appliances are about 85-90% effective when the problem is limited to snoring.

When treating obstructive sleep apnea, oral appliances are 60-80% effective, depending on the severity.

While oral appliances tend to be more effective for treating mild to moderate obstructive sleep apnea, they may be successful in patients with severe apnea as well.