A magnetic field generator which provides greater control over the magnetic field is provided. One method embodiment includes receiving a three-dimensional data set including a first jaw and a second jaw of a three-dimensional digital dental model and receiving a two-dimensional data set corresponding to at least a portion of the first jaw and the second jaw. The diameter of the cannula first portion is smaller than the diameter of the cannula second portion and the cannula first and second portions join at an annular shoulder which limits the partial insertion of the cannula. The pushing blade includes cross-shaped pushing blade single bodies having a predetermined height juxtaposed in a plurality of rows, with each pushing blade single body being capable of entering a blade space defined between the longitudinal receiving blades and the transverse receiving blades in the receiving blade. The measuring cell is characterized in that the electrode is electrically connected through the base body and that the measuring chamber has a smooth surface in the contact zone, said surface having a contact pin that is guided in a bore through the base body.