In this study the compensating angle on the Hanau XP-51 articulator was found to be proportional to the magnitude of the intercondylar distance. Further, eccentric movement of the Hanau 130-7, the Hanau XP-51, and the Whipmix articulators, at the cusp level, followed that displayed by the control articulator when guided by straight condylar elements. For restoration to function harmoniously in the patient's mouth they must be made on an instrument that can accurately reproduce selected movements of the mandible. The choice of articulator depends upon the precision with which the dentist wishes to work. The mechanisms of articulators should be precise, easy to adjust, and simple to understand.