ORTHOPEDIC JAW MOVEMENT OBSERVATIONS .5. TRANSVERSAL CONDYLAR SHIFT IN PROTRUSIVE AND RETRUSIVE MOVEMENT

Unguided protrusive and retrusive mandibular movement was investigated in 76 asymptomatic volunteers and temporomandibular joint (TMJ) patie nts using computerized axiography. In 38 of these subjects, guided pro -/retrusion was also recorded. Measurements were performed in a three- dimensional Cartesian coordinate system (x = anteroposterior; y = tran sversal, toward the hinge axis; z = craniocaudal). Transversal shift ( y) was measured and evaluated as well as the distance ''s'' and horizo ntal condylar inclination (HCl) at the point of maximum transversal de viation. The patterns of the tracings were analyzed with a view to dia gnostic improvements. The objective of this study was to evaluate tran sversal shift and to examine the postulate of symmetrical behavior of the TMJs in pro-/retrusion. The mean mandibular shift was 0.15 mm to t he left. This maximum deviation was seen in a mean distance ''s'' of 7 .42 mm in relation to the Cartesian coordinate system in reference pos ition. These results suggest a functional dominance of the right part of the mandible in protrusive and retrusive movement.