Follow-up study of condylar bony changes using helical computed tomography in patients with temporomandibular disorder

We investigated condylar bone changes in 1032 joints from 516 subjects in order to clarify the incidence and type of bone changes in the temporomandibular joint (TMJ), and alteration of the change during follow-up, in patients with temporomandibular disorders (TMD).We classified condylar bone change into five types on multiplanar reformatted (MPR) images of helical CT: N, no bone change; F, flattening; E, erosion with or without roughening; D, deformity; S, deformity accompanied by erosion with or without roughening. In 51 of 516 subjects, follow-up CT examination was performed and transition of condylar bone change was observed.Condylar bone change was seen in 617 (63.7%) of 1032 joints and in 70 (68.6%) of 102 follow-up joints. The number of joints of Types D and S increased at follow-up, but those of Types N, F and E decreased.In this study, the main direction of transition of condylar bone change in joints with TMD was absorptive bone change to absorptive with sclerotic (proliferative) bone change and further to sclerotic (proliferative) bone change. Our classification of condylar bone change was thought to be convenient for the evaluation of bone change in TMD.