Disclosed herein are mandibular advancement devices comprising an upper splint and a lower splint, where the upper splint comprises one or more upper fins, where each upper fin is located at a distance UD from back of the upper splint; the lower splints comprise one or more lower fins, where each lower fin is located at a distance LD from back of the lower splint; where the position of the upper and lower fins is unchangeable. Also disclosed are methods of reducing partial constriction of airway during sleep for a patient, the method comprising identifying a patient in need thereof; and administering to the patient the disclosed mandibular advancement device. Also disclosed are methods of manufacturing a mandibular advancement device, the method comprising obtaining measurements from a patient's dentition; digitally designing a mandibular advancement device; and milling the mandibular advancement device.