A device for treatment of sleep apnea or snoring of a user comprises an upper oral splint adapted for an upper jaw of the user, and a lower oral splint (20) adapted for a lower jaw of the user. At least one of the oral splints comprises adjustment devices with a fixation device for adjustable and detachable fixation of an abutment element. Since the abutment elements are adjustable and detachable, a flexible device is provided wherein the setting can be adjusted and parts can be replaced when needed.
