[Zonograms of temporomandibular joints in patients with anterior displacement of the disc without reduction].

Zonogram investigations were made of 86 temporomandibular joints in 81 patients who were diagnosed by video-fluoroarthrogram as having anterior disc displacement without reduction. Comparisons between of condylar shape and movement, clinical phenomena, and disc perforation were made. Results 1. Condylar deformity on zonograms was classified into 3 types: flattening, osteophyte, and concavity. Condylar deformity was much higher in patients than in normal volunteer controls. 2. Condylar movement patterns were classified into 3 types: coordinated, uncoordinated, and limited. Coordinated movement was frequently observed in normal volunteers, and limited movement was common in the patients group. 3. In the patients group, condylar deformity was observed in both the displaced and the non-displaced sides, although it occurred with extremely high frequency in the displaced side. Condylar deformation was more common when the disc was perforated than when it was unperforated. A correlation between condyle deformity and pain on the non-displaced side was suggested; but no correlation existed between condylar deformity and such elements as age, joint sounds, mouth opening range, and locking term. 4. Limited condylar movement occurred more frequency in the displaced than in the non-displaced side. Consequently values for limited movement without joint sounds were high for the displaced side; and coordinated movement without joint sounds was frequent in the non-displaced side. There was no correlation between condylar movement and such elements as mouth opening range, locking term, and disc perforation. 5. Comparisons of condylar deformity and movement with clinical phenomena and disc perforation showed no instances of high (greater than or equal to 0.5) correlation. These results suggest that, in the temporomandibular joint, changes occur in both hard and soft tissues and that these changes take place on both the displaced and non-displaced sides.