Evaluating the sagittal base relationship in an Egyptian population sample using the beta angle

Cephalometric analysis using the ANB angle and the “Wits appraisal” to diagnose sagittal base relationship can be very deceiving due to the many factors affecting these measurements and camouflaging the real relationship. The Beta angle is independent on any cranial land marks and gives a better picture of the sagittal base relationship. The aim of this study was to find the mean and cut off points of this angle (previously developed at Tufts university) in an Egyptian Population sample. 120 patient’s files were selected and screened on the base of 3 criteria: angle ANB, “Wits appraisal” and XY axis to differentiate between classes I , II and III Skeletal patterns. Using ANOVA and Posthox analysis the mean value of Beta angle for class I was 32.21 degrees for class II 25.1 degrees and for class III 41.8 degrees. The Receiving Operator Characteristic curve analysis showed that the cut off point between skeletal classes I and II was 29o and between skeletal classes II and III was 34 degrees.