The wits appraisal using three reference planes and its interaction with the ANB angle among a sub-set of Nigerians"

Abstract

Aims: Conjoint analysis of orthodontic patients using the Subspinale (A-point) Nasion-Supramentale (B-point) (ANB) angle and the Wits appraisal is popular in many practices. This study aimed to present reference values for the Wits appraisal among Nigerians using three horizontal reference planes namely the bisected occlusal plane (BOP), the functional occlusal plane (FOP) and the maxillo-mandibular angle bisector (MM°bisector) plane. It also assessed the relationship of the Wits appraisal with the ANB angle and its interaction with clinical measures of sagittal skeletal relations among subjects with malocclusion. Methodology: One hundred participants with normal occlusion and 120 with malocclusion were recruited in the study. Cephalometric radiographs were taken for all participants. Each radiograph was manually traced on a 0.003 matted cellulose acetate tracing paper using a sharpened 2H pencil. The Wits appraisal and ANB angle were determined. Data was analyzed using SPSS version 19. Results: The mean age was 20.7±4.9 years for those with normal occlusion and 18.8±6.5 years in the malocclusion group. There were 91 (41.4%) males and 129(58.6%) females. Mean values for the Wits appraisal using the BOP as reference, was - 1.27±2.91 mm, with the FOP, it was -3.54±3.24mm, while with the MM° bisector plane, it was - 4.75±2.94mm. The ANB angle showed highest correlation with the MM° bisector plane Wits value(P<0.001)