Trajectories of condylar points during nonworking side and protrusive movements of the mandible.

STATEMENT OF PROBLEM: During lateral excursive and protrusive jaw movements, condylar points are distant from any instantaneous rotational center. Therefore, it is likely that different condylar points would follow similar trajectories during these movements. PURPOSE: This study evaluated the effect of changes in condylar point location on trajectories of condylar points on the nonworking side and during a protrusive jaw movement and compared these changes with the effects described for open-close and working-side condylar movements in the same group of subjects. METHODS: The movements of 5 clinically determined condylar points were recorded in 44 subjects during a contralateral excursion and during protrusion (7 radiographically determined condylar points in 2 subjects). RESULTS: During any single jaw movement, the trajectory of each condylar point was similar in form and dimension to the other condylar points within that subject. CONCLUSION: Changes in condylar point location had little effect on the trajectories of condylar points on the nonworking side and during protrusive jaw movement.