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.
