[Geometric-mathematical analysis of errors during transfer to the articulator and their practical consequences. II]

With the aid of a computer faults are examined which result in the occlusal surfaces when several articular parameters are simultaneously wrongly applied in laterotrusion. The calculations which are derived from the geometrical relations of the Dentatus articulator refer to a circular field of 3 mm radius on a molar tooth. Vertical deviations, which are caused by faulty setting up of a preferred articulator size, evidently depend on the angle of the joint on the balancing side and depend on the working side on the sagittal position of the model in relation to the condylar axis and on the length of the condylar axis. In the most unfavourable case, errors of the order of 1.3 mm on the balancing side and of 0.75 mm on the working side were demonstrated. As regards horizontal deviations, all articulator sizes were shown to be independent of one another. The effects of faulty setting up on periodontal strain is presented in a practical example.