Measurement of masticatory movement by a new jaw tracking system using a home digital camcorder.

The aim of this study was to confirm the precision of our simple and inexpensive jaw tracking system which combined the use of a digital camcorder and a motion capture software developed lately. A marker was attached to the mandibular incisors of the subject, and a mirror was assembled beside the subject's face to detect antero-posterior movement during chewing. Jaw movements, including the mirror images, were recorded by a digital camcorder. The movements were traced by a motion capture software and translated into 3D data using original handmade software. To confirm the beneficial performance of our system in measuring masticatory movement, the masticatory movements of five subjects were simultaneously recorded together with a conventional jaw tracking system. Trajectories obtained from both systems were similar, and the correlation coefficient values by simple regression analysis between both trajectories were 0.9 or higher for all subjects. It was confirmed that our system could record masticatory movement with sufficient precision equivalent to that of a conventional jaw tracking system.