What does Wits appraisal measure?

• A. AP skeletal discrepancy on the occlusal plane using A- and B-points; independent from cranial base; supports diagnosis when SNA/SNB ambiguous.
• B. Vertical jaw relationship.
• C. Airway dimension.
• D. Tooth enamel thickness.

Answer: (A)

Wits appraisal focuses on the anteroposterior relationship between the jaws, using the occlusal plane as a reference so the measurement isn’t swayed by cranial base length or orientation. On a cephalogram, you identify the A point (subspinale) and the B point (supramentale), drop perpendiculars from each onto the occlusal plane, and measure the distance between the projected points A' and B' along that plane. The size and sign of this distance reflect the sagittal jaw discrepancy: a larger positive value points to a Class II pattern (maxilla ahead of mandible), a negative value points to a Class III pattern (mandible ahead), and near-zero suggests Class I.

This method is especially useful when the standard SNA/SNB angles give ambiguous results or are confounded by the cranial base, because it assesses jaw relationships in a way that is less dependent on base length or angle. It does not assess vertical jaw relationships, airway dimensions, or enamel thickness, which explains why those options aren’t what Wits appraisal measures.