The Measurement of Mandibular Movement by Experimental Jaw Tracking Device using Two Magnetic Fields in Quadrature Phase.

The purpose of this research was to evaluate the manipulation of the newly developed six degrees of freedom jaw tracking device using magnetic fields in quadrature phase. Jaw movements were recorded by this device in 15 female subjects. Further the jaw movement data was compared to that of 15 male subjects recorded by digital jaw tracking device (MM-JI). None of the subjects showed any clinical signs of craniomandibular disorder.The results were as follows:1. Manipulation of this device has been improved dramatically compared to the digital jaw tracking device (MM-JI), however it still needs improvement, such as the ability of jaw movement recording range.2. The maximal jaw opening movement recorded in male subjects was significantly greater in comparison with that in female subjects (p<0.01).The maximal condylar movement and mandibular rotation in male subjects were also greater than those in females. However, no significant difference was observed between males and females (p>0.05).3. The influence of measuring point on the mandible or sex differences was found to be minimal in determining maximal mandibular rotation and therefore, it can be regarded as an important parameter of movement to the temporomandibular joint.