Abstract: There is disclosed an improvement for dental articulators of the Arcon type. The improvement comprises spacer plates adapted to be mounted to the upper and lower frame members of the articulator by the mounting screw of the articulator so that the dental casts with reduced vertical dimension can be mounted between spacers thereby allowing the overall vertical dimension of the dental casts to be reduced to save material and storage space. The improvement also maintains the positional relationship between the frame members and the dental cast by duplicating on the opposing surfaces of the spacers positioning posts in the same position as the positioning posts found on the upper and lower frames. The improvement allows smaller, less costly, more easily stored dental casts to be used without losing any of the capacity of the articulator to duplicate the manipulation of the human mandible.