An analytic method for evaluating condylar position in the TMJ and its application to orthodontic patients with...

The purpose of this study was to develop a new method for evaluating the three-dimensional position of the mandibular condyle relative to the glenoid fossa and further to investigate its clinical application to orthodontic patients with temporomandibular disorders (TMD). A three-dimensional configuration of the temporomandibular joint was constructed by 108 triangles for the condyle and 180 triangles for the glenoid fossa. The shortest distance between the condyle and glenoid fossa (CGFD) was calculated in the model along a line perpendicular to the center of gravity of a triangle on the condyle. The CGFD was determined in the anterior, posterior, middle, lateral, and medial areas on the condyle. Preliminary investigation revealed that the present technique is accurate, regardless of condylar rotation and/or inclination to the tomographic table. The technique was applied to the diagnosis of orthodontic patients with painful clicking and TMD. It is shown that the present approach provides a method for evaluating the positional relationship between the mandibular condyle and glenoid fossa in patients with TMD.