Axiographic tracings of temporomandibular joint movements

Three-dimensional condylar movements of 49 symptomatic and asymptomatic volunteers were recorded with a hinge axis tracing system axiograph during maximal opening, protrusion, and mediotrusion. The tracings displayed in sagittal and frontal planes were measured to evaluate biomechanics of the temporomandibular joint. The only differences in condylar tracings between symptomatic and asymptomatic groups were in the right joint, recorded in the sagittal plane during maximal opening, and the Bennett angle. The symptomatic group had a significantly longer condylar path and a smaller Bennett angle compared with the asymptomatic group. The results were interpreted as indications of adaptive morphologic instead of pathologic changes. The alterations in condylar tracings as an indicator of joint pathology should be considered cautiously.