Relation of the Wits appraisal to the ANB angle: a statistical appraisal.

The hypothesis that the relationship between the ANB angle and the Wits appraisal can be expressed by measuring the individual variations in their reference systems and by constructing a model of regression between them and a few parameters describing the reference systems was tested with material consisting of 30 lateral cephalometric radiographs of untreated orthodontic patients with different types of skeletal and/or dentoalveolar malocclusions. The results indicated that approximately 93% of the variation of the Wits appraisal could be explained by the variation of the ANB, NSL/OL, and SNA angles. The study also showed that the results given by different measurements with different reference systems, such as the ANB angle and the Wits appraisal, cannot be directly compared. To obtain comparable interpretations, one should correct the results of both measurements in relation to the variations in their reference systems.