The “Universal” articulator represents Hall's second endeavor in designing articulators according to the theory that articulators more accurately record the positional (static) relations than the functional relations (movements) of the mandible. The “Universal” is essentially a simple hinge articulator; however, on the lower member is attached a “record cup” for mounting the lower cast in individual positional relationships. The technique involves arbitrarily mounting the maxillary cast and tapering and soaping the mandibular cast. Check-bite records are made (centric, right and left lateral and protrusive) and the mandibular cast and the prepared mandibular casts placed in the plaster filled “record cup” for each check-bite record, thereby securing four positional mandibular records. The teeth are initially set in centric occlusion with the mandibular cast in the centric record and then all other relations are set and adjusted by replacing the mandibular cast in each appropriate eccentric record. According to Hall, the “Universal” Articulator can be converted to a grinding machine by interposing double thickness of rubber dam between the bearing points of the screws forming the hinge joint and, with carborundum applied to the teeth, hand grind the teeth according to the plaster records of the positional relations of the mandible.
Dr. Edgar N. Starcke's articles in the Journal of Prosthodontics have more information on the history of articulators.