A Study of the Fischer's Angle

Abstract

Based on the results measured by the extraoral tracing device such as mechanical pantograph, it has been widely believed that sagittal lateral condylar path is longer in length and steeper in inclination than sagittal protrusive condylar path. The difference of the angle between sagittal lateral and protrusive condylar path has been known as Fischer's angle and its value is to be 5° in average.
In this study, the various data of sagittal condylar path inclinations measured electronically were recalibrated to the same horizontal reference plane, and compared. As the result, it was shown that the average value of Fischer's angle is -0.1°. Therefore, it is concluded that Fischer's angle is zero.
Fischer's angle is observed by mechanical pantograph measurement. Tracings are drawn on the recording table which is placed outside of the condyles. Thus, the inclinations of lateral condylar paths are drawn apparently longer than protrusive paths, although the both paths are not different in inclination. Through this study, it is concluded that the difference between lateral and protrusive condylar path inclinations is not necessary to reproduce on the articulator.