Abstract: An instrument and method to measure the position of the occlusal plane of the mouth with reference to the structural features of the cranium. The instrument includes a vertical face bow, positioned on the nasal bridge and the forward edge of the base of the chin. The device employs light beams to make measurements of the patient's occlusal plane and the nose-to-chin distances. The device utilizes an internal processor to make the necessary calculations, provides direct numerical readouts, is battery powered and self-calibrating. The entire device is sealed to permit cold sterilization by liquids.