[Morphological analysis for kinetic X-ray images of the temporomandibular joint]

The purpose of this study was to develop a screening technique for temporomandibular disorders (TMD) and assist dentists in objectively observing and evaluating pre/post-treatment status. Dynamic images of the temporomandibular joint (TMJ) from one healthy volunteer were obtained by digital fluoroscopy in the lateral view on both right and left sides. Outlines of the glenoid fossa and the condyle were extracted, respectively, by using sobel operator (7x7) thresholding and labeling. Morphological parameters in time-sequence, such as fossa ratio, area, and distance of the joint space, were then analyzed. There were no differences between manual and computer analysis in extracting the outline of the glenoid fossa and the condyle. Deformity of the outline of the glenoid fossa and the condyle was not identified in this subject. The fossa ratio was 0.30+/-0.01 on the right and 0.29+/-0.02 on the left. The area and distance of the joint space in the post-glenoid fossa were slightly larger than those in the articular eminence on both sides. These morphological parameters were useful for screening and pre- and post-treatment evaluation of TMD patients.