Condylar movements of temporomandibular disorder patients with intermittent lock: a pilot study

The purpose of this study was to clarify which direction of the condylar path is advantageous for releasing TMJ intermittent lock. The subjects were ten patients with temporomandibular disorders (TMD) and intermittent lock caused by anterior displacement of disks without obvious medial or lateral displacement. The patients could not open their mouths fully in habitual opening but could open fully in an intentional winding opening with reduction of the anteriorly displaced disks (winding opening). The two kinds of movement at the kinematic condylar point were measured in each subject and compared. The length of the condylar path in winding opening was significantly larger than that in habitual opening. The affected side condyle of winding opening traced medio-inferior paths in the early part of the condylar translation in comparison with habitual opening. From the viewpoint of the condylar path, the medio-inferior direction of condylar translation is thought to be advantageous for releasing intermittent lock.