Relationship between the temporomandibular joint and pantographic tracings of mandibular movements

Lateral polytomography of the TMJ and pantographic tracings of mandibular movement were performed in 30 patients with TMJ pain-dysfunction syndrome. The condyles were classified as rounded or flattened. The articular eminences were classified as convex or flattened. Two types of immediate side shift, progressive side shift and vertical protrusive tracing, were observed. Type A was curved, Type B was straight. A significant relationship was found between the shape of the TMJ and the tracing pattern. Type A immediate side shift (when present), progressive side shift, and vertical protrusive tracings were more typical of patients with rounded condyles and convex articular eminences. Type B was typical of patients with flattened condyles and, to a lesser extent, flattened articular eminences. Superior displacement of the rotating condyle was found only in patients with flattened condyles.