Displacement analysis of the temporomandibular condyle from magnetic resonance images.

A technique was developed to investigate the condylar displacement of the human temporomandibular joint. Condylar displacement was analyzed from magnetic resonance images of the joint. Fourteen static images were obtained during incremental jaw closure. Landmarks were identified on the magnetic resonance images and reference points were digitized. The condylar displacement was calculated based on an optimization algorithm. The technique was proven to be reproducible based on two feasibility tests. The results provided quantitative descriptions of the condylar displacement as a function of a prescribed jaw movement. The displacement was characterized by a translation of an anatomical point on the condyle and a rotation of the mandible. The condylar displacement was 6 mm at a mouth opening of 17 mm. Maximum rotation of the mandible was 12.3 degrees C. The motion of the condyle produced by the mechanical guidance system used in this study may be characterized as a small forward translation at the beginning of jaw opening, followed by a combination of translation and rotation.