Ryusuke Nakai1, 2, Takashi Azuma3, Keiji Shigeno1, Osamu Takizawa4, Hiroo Iwata1
1Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan; 2Kokoro Research Center, Kyoto University, Kyoto, Japan; 3National Institute of Information and Communications Technology, Suita, Osaka, Japan; 4Siemens Japan K.K., Tokyo, Japan
We analyzed trajectories of the mandibular condyles and articular disks during mouth opening and shutting movements using multi-section dynamic imaging. The conditions of masseter muscles were examined based on high-resolution 3D-images, the DTI technique, and T1 and T2 values; and the relationships among mandibular movement, articular disks, and the conditions of the masseter muscles were determined. In the present investigation of mandibular movement, articular disks, and masseter muscles, MRI revealed relationships among mandibular trajectories, disorder in articular disks, and the condition of the masticatory muscles. This study shows the importance of the MRI technique for identifying causes of temporomandibular-joint disease.