[Kinetic radiography and functional analysis of the temporomandibular joint (TMJ)].

To develop a method of kinetic radiography and a computer-aided diagnosis (CAD) system for quantitative evaluation of the temporomandibular joint (TMJ), dynamic images of the TMJ from one healthy volunteer were obtained by fluoroscopy in the lateral view on the right and left sides. The accumulated image subtraction technique extracted the condyle in each image. A sequential similarity detection algorithm (SSDA) was employed to trace the movement path and the velocity of the condyle. The shape of the path of the right condyle was smoother than that of the left condyle. The size of the maximum vertical and horizontal movements of the condyle were 4.6+/-0.1 mm and 15.0+/-0.2 mm, respectively. The velocity of the movement of the condyle was higher in the area close to the articular eminence than in any other area during the opening and closing of the mouth. This CAD system will contribute to the kinetic analysis of the TMJ for screening, follow-up study, and informed consent, providing speed, quantitation, and cost-effectiveness.