Kenneth H. Swanson
T M J Instrument Co., Thousand Oaks , California
The T M J Articulator can be classified as a "scribing articulator". Scribing articulators have generally been considered to be those with functionally generated guide controls. The articulators have scribing assemblies that usually consist of two or three receptacles to hold the scribing material with corresponding tracing devices. The receptacles are filled with a soft moldable material and the tracing devices function to displace the soft material before it solidifies. Hand-manipulating the upper member against the lower member of the articulator by following an intraoral stereographic record (also known as, "functionally generated path" or "chew-in" is the technique that is used to generate the custom guide paths. The T M J is considered a fully adjustable or gnathological instrument. It was designed with all the attributes of an arcon instrument with custom molded glenoid fossae that reproduce both the inclination and curvatures of the eminentiae. It also had side shift controls at the fossa site as well as custom incisal guide control. There are provisions for intercondylar distance adjustment and for location of the hinge axis.
Dr. Edgar N. Starcke's articles in the Journal of Prosthodontics have more information on the history of articulators.