Quantitative measurements of the articular areas of mandibular condyles with temporomandibular joint disorders using magnetic resonance imaging

Objective: The authors sought to clarify the variation in the condylar anterior functional surface (AFS) of patients with temporomandibular joint (TMJ) disorders using quantitative measurements by magnetic resonance imaging (MRI). Methods: MR images of 68 joints (2 males, 32 females) were used. The subjects were classified into three groups: with/without defects of cortical bone groups and a combination group without defects. The AFS was measured as the length between the protrusive point and the apex of the condyle on MRI (4-mm-thick slices), and the quad value of the length was defined as the area on the slice. The summed quad values of all slices were used as the AFS area. Differences in the areas among the three groups were compared by one-way analysis of variance (ANOVA). Results: The non-defect group had significantly larger AFS areas than the defect group. Conclusions: Quantitative measurement on MR images clarified the changes in the condylar sagittal appearance.