A comparison between arbitrary and kinematic mandibular hinge axis location in full mouth rehabilitation patients : an in vivo study

Abstract EN

Background : casts are often transferred to the adjustable articulator by arbitrary means because the method of locating the mandibular terminal hinge axis is thought to be complicated and time-consuming.

The aim of this study was to compare between the arbitrary and kinematic location of the hinge axis in full mouth rehabilitation patients.

Materials and methods : arbitrary hinge axis was marked at eleven mm from the superior border of the tragus of the ear on both sides of fifty full mouth rehabilitation patients.

Terminal hinge axis of each patient was located using the TMJ kinematic hinge axis locator.

Position differences between the arbitrary and terminal hinge axes were recorded.

Results : results indicated that 28% of the patients possessed terminal hinge axes located in an anterior-inferior position to their arbitrary hinge axes from the superior border of the tragus of the ear.

Conclusion : careful location of the terminal hinge axis as the posterior reference point instead of depending upon an arbitrary marking is recommended to avoid potential sources of error in mounting casts on the adjustable articulator thus preventing statistically different articulator settings.