A device (1) for treatment of sleep apnea or snoring of a user comprises an upper oral splint (10) 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 (25) with a fixation device (30) for adjustable and detachable fixation of an abutment element. Since the abutment elements (40a, 40b) are adjustable and detachable,a flexible device is provided wherein the setting can be adjusted and parts can be replaced when needed.
