Observation of the practical application of the arbitrary face bows inspired the question, if the sagittal positioning of the face bow and its reproducibility depends on the force applied to the nasion support. In this case, a novel nasion support with an integrated stress-braker should limit the forces applied and thus allow better for reproducibility. Objectives: Hence, the aim of this study was to determine whether the novel nasion support increases reproducibility of arbitrary face bow transfers. Methods: 22 undergraduate dental students participated in a study based on a crossover-design. No participant had prior practical experience in mounting the arbitrary face bow. All participants received the same instruction about the use of arbitrary face bows. The face bow (Artex, Girrbach Dental Systems, Germany) was mounted for all experiments on one patient only. Each participant performed two face-bow transfers consecutively: one time, the standard nasion support was used, the other time, a novel nasion support was used. Following every face-bow registration, the informations was transferred by mounting prefabricated dye cast in an articulator (Artex, Girrbach, Germany). The orientation of all models in the articulator was measured with a 3D-Digitizer (Gamma, Klosterneuburg, Austria) using three predetermined sites (between the first incisors and on right and left second molar). The difference between mean and specific positions (x,y,z) was calculated and the standard deviations were computed. Tests on significancy were performed using Student's t-Test. Results: Reproducibility of the new nasion support was improved when looking on sagittal (SD new/old 1,3684/2,0519; p<0,01) and vertical (SD new/old 0,7539/1,0284; p<0,01) coordinates. In the horizontal plane reproducibility (SD new/old 1,8449/1,7786) did not change significantly (p>0,05). Conclusion: Use of the novel nasion support increases the reproducibility of face bow transfers significantly in two planes.

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