[Analysis on deformity of disk associated with internal derangement of TMJ]

Internal derangement of temporomandibular joint has been studied mainly arthrographically about disk position, but it was reported that morphologic alterations and histo-chemical changes of disk were frequently observed in joints with internal derangement. The aim of this investigation was to study the relationship between deformity of disk and the kind of internal derangement of TMJ (anterior disk displacement with or without reduction). We analysed arthrographically the configuration of anterior displaced disk according to the criteria of Westesson. Deformity of disk was seen in 35 joints in 60 joints (58.3%) associated with anterior disk displacement with reduction, and 51 joints in 66 joints (77.3%) without reduction. Statistically significant difference existed between the distribution of disk configuration in with-reduction and without-reduction. We analysed the relationship between distribution of disk configuration and age, clicking period and locking period. In cases long suffering from clicking and locking, no-deformed disk were seen, and any certain type of deformed disk did not increase. From above results it was suggested that there was a strong relationship between distribution of disk configulation and types of anterior disk displacement (with or without reduction).