[The discriminatory force of 3 sagittal measurement relations of the jaw bases].

The angle ANB relates the apical base not only to each other but also to point nasion and the profile. Furthermore, it is influenced by prognathism and inclination of the maxillo-mandibular complex. Both the angle AB/Occlusal plane and the "Wits" appraisal are based on elements within the maxillo-mandibular complex and not influenced by structures outside this complex. Cephalograms of 4 groups of 25 cases each comprising ideal occlusion, class-II/1, class-II/2 and class-III malocclusions were collected. Angle ANB, angle AB/Occlusal plane and "Wits" appraisal in 10 variations using points A and B according to Downs, As and Bs according to Herren and the occlusal plane using Incsup., Incinf. and Incinter and the molar point Mo (Hügli) were determined. By means of a discriminant analysis the discriminatory power of these variations were calculated. Variations using the points As and Bs and point Mo gave better results in separating 100 cases according to their relation of the apical bases. The results of the stepwise discriminant analysis reveal a high percentage of "right" classification. It is possible to draw borderlines in the continuum of values, allowing with high probability a classification of each case according to Angles classification when more than one measurement is utilized.