To investigate the correlation between clinical dysfunction index (Di) and condylar bony changes, glenoid fossa bony changes and joint space changes.
Clinical data and cone beam computed tomography (CBCT) images of 240 patients with temporomandibular joint osteoarthritis (TMJ OA) were analyzed. The patients were assigned a score of Helkimo's clinical Di ranging from 1 to 25 and thereafter divided into 3 groups by the degree of Helkimo's Di. The condylar bony changes observed with CBCT were graded by the classification method of Koyama et al. Glenoid fossa bony changes and joint space changes were both classified as "positive" or "negative". Spearman's rank correlation test was used to correlate the score or degree of Helkimo's Di with the maximum condylar bony changes, glenoid fossa bony changes, and joint space changes.
There was a significant correlation between the Helkimo's Di score and the maximum condylar bony changes (P ≤ 0.0001) and glenoid fossa bony changes (P ≤ 0.0001), and there was a poor correlation between the Helkimo's Di score and joint space changes (P = 0.184). Furthermore, there was a significant correlation between the degree of Helkimo's Di and the maximum condylar bony changes (P ≤ 0.0001) and glenoid fossa bony changes (P ≤ 0.0001), but there was a poor correlation between the degree of Helkimo's Di and joint space changes (P = 0.346).
Both the score and degree of Helkimo's Di were highly correlated with maximum condylar changes and glenoid fossa bony changes, but not with joint space changes.